Latin name of the genus: Echinaceae purpureae radix
Botanical name of plant: Echinacea purpurea (L.) Moench.
English common name of herbal substance: Purple Coneflower Root
1.1. Description of the herbal substance(s), herbal preparation(s) or combinations thereof
Echinaceae purpureae radix (European Pharmacopoeia monograph reference 01/2008: 1824)
Echinaceae purpureae radix consists of the whole or cut, dried underground parts of Echinacea purpurea (L.) Moench. It contains not less than 0.5% for the sum of caftaric acid (C13H12O9; Mr 312.2) and cichoric acid (C22H18O12; Mr 474.3) in dried drug.
Constituents (Barnes et al., 2005; Barnes et al., 2007; Bauer and Remiger, 1989; Bradley, 2006; ESCOP, 2009; Bauer and Liersch, 1993; Mazza and Cottrell, 1999; Wolters Kluwer Health, 2004; PDR, 2007):
−Alkamides (0.01-0.7%): mainly isobutylamides of straight-chain fatty-acids with olefinic and/or acetylenic bonds e.g. isomeric dodeca-2E,4E,8Z,10E/Z-tetraenoic isobutylamide. Undeca-2Z,4E– diene-8,10-diynoic acid isobutylamide is also prominent. Isobutylamides contain mainly 2,4- dienoic units.
−Caffeic acid derivatives (2.0-2.8%): principally cichoric acid (2,3-O-dicaffeoyltartaric acid, 1.7- 2.4%) and caftaric acid (2-O-caffeoyltartaric acid, ca. 0.2-0.8%) also echinacoside, verbascoside, caffeoylechinacoside, chlorogenic and isochlorogenic acids.
−Polysaccharides and glycoproteins: arabinogalactans, and an arabinogalactan-containing glycoprotein with a sugar component consisting of arabinose (64-84%), galactose (2-5%) and galactosamine (6%).
−Volatile oil (0.1%): caryophyllene, caryophyllene oxide, humulene, α-phellandrene, limonene, camphene, aldehydes and dimethyl sulphide.
−Other constituents: small amounts of polyacetylenic compounds polyynes (0.01 mg/100 g including trideca-1-en-3,5,7,9,11-pentaine, trideca-1,11-dien-3,5,7,9,-tetraine, trideca-8,10,12- triene-2,4,6-triine)
−Non toxic pyrrolizidine alkaloids: tussilagine, isotussilagine.
Baiciunaite et al. (2015) evaluated the protein content in dried roots of Echinacea purpurea after homogenization of roots with liquid nitrogen, extraction in 0.01 mol /L phosphate-buffered saline (PBS) and purification followed by fractionation of proteins using gel filtration chromatography. Total concentration of proteins was measured using the Bradford method, and evaluation of the molecular mass of proteins was accomplished by applying the SDS-PAGE gel electrophoresis. The Bradford assay revealed that the highest concentration of proteins in fractions collected after gel filtration chomatography was 4.66-6.07 mg/ml.
Comminuted herbal substance for decoctions and galenic preparations (PDR, 2007; Blumenthal et al., 2000; ESCOP, 2009)
Dry extract (6.5:1), extraction solvent: ethanol 45% (V/V).
Dry extract (5.5-7.5:1), extraction solvent: ethanol 45% (V/V).
Tincture (1:5), extraction solvent: ethanol 55% (V/V) (ESCOP, 2009; Blumenthal et al., 2000; Bräunig et al., 1992; Barrett et al., 1999; Melchart et al., 1994).
•Combinations of herbal substance(s) and/or herbal preparation(s) including a description of vitamin(s) and/or mineral(s) as ingredients of traditional combination herbal medicinal products assessed, where applicable.
1.2. Search and assessment methodology
For the research, the databases of PubMed, ScienceDirect, Cochrane Database of Systematic Reviews and TOXLINE were used.
The research in PubMed contained the keywords “Echinacea purpurea radix” (42 results) and “Echinacea purpurea root” (53 results). All articles from 12 March 2010 to 05 April 2016 were included and then assessed due to their value for medicinal use of Echinacea purpurea radix. Articles with a reference to Echinacea’s health-related processes were included, whereas articles without any reference to physiological processes (e.g. the development of a new validation method) were excluded.
For the research in ScienceDirect, the keywords “Echinacea purpurea root” were used, including articles from 2010 to 08 April 2016. Therefore, 220 results were recommended and assessed as described above.
The same procedure was followed with EMBASE (3 results, 13 April 2016), BioMed Central (22 results, 13 April 2016) and Micromedex (0 result, 13 April 2016).
Reviews were searched in Cochrane Database of Systematic Reviews, typing in “Echinacea purpurea root”. One result was obtained (13 April 2016).
For toxicological data, the advanced search in TOXLINE was carried out under the following conditions:
Search term: singular/plural, records with all of the words, all fields, “Add chemical synonyms and CAS numbers to search”, “Include PubMed records”, maximum records returned: 50 000, year of publication 2010 through 2016, all languages, all TOXLINE components except of PubMed. Three results were found (13 April 2016).
The articles were divided up first into clinical and non-clinical, in vitro and in vivo and then into more specific data, e. g. Echinacea’s immunomodulatory, anti-inflammatory and anti-infective effects (primary pharmacodynamics), its influence on other health-related processes (secondary pharmacodynamics, e.g antioxidant activity), pharmacokinetics, toxicological effects and interactions with other drugs.
Additionally, the research was about “Echinacea purpurea root” in WHO monographs (2 results, but before 2010), Health Canada monographs (1 result, “Echinacea purpurea”) and UKPAR (all 13 April 2016).
Search engines used: Google
Scientific databases: PubMed, ScienceDirect, Embase
Medical databases: Medline, PubMed, ScienceDirect, BioMed Central, Micromedex
Toxicological databases: TOXLINE
Pharmacovigilance resources: UKPAR, WHO, Canadian monograph
Data from EU and non-EU regulatory authorities: UKPAR, WHO, Canadian monograph
Other resources: Library of the Faculty of Pharmacy of Ljubljana
2. Data on medicinal use
2.1. Information about products on the market
2.1.1. Information about products on the market in the EU/EEA Member States
Information on medicinal products marketed in the EU/EEA
Table 1: Overview of data obtained from marketed medicinal products
This overview is not exhaustive. It is provided for information only and reflects the situation at the time when it was established.
Information on relevant combination medicinal products marketed in the EU/EEA
Several combination products wit Echinacea purpurea herba, Baptisiae rhizoma, E. pallidae radix; Thujae occidentalis herba and/or S. officinalis folium are authorised/registered in serveral MS. The indications are: “… prevention and supportive treatment of common cold …”.
Information on other products marketed in the EU/EEA (where relevant)
No data availble.
2.1.2. Information on products on the market outside the EU/EEA
2.2. Information on documented medicinal use and historical data from literature
Herbal teas and tincture prepared of Echinaceae purpureae radix are mentioned in the literature.
Table 2: Overview of historical data
There is no evidence of 30-year of medicinal use of the comminuted or powdered dried roots and of the tincture in the EU. These preparations are therefore not included in the monograph on Echinaceae purpureae radix.
2.3. Overall conclusions on medicinal use
Two herbal preparations with sufficient documentation for 30 years of traditional use are reported:
Table 3: Overview of evidence on period of medicinal use
At the time of the preparation of the first monograph on Echinacea purpurea root in 2010, the product on the market with documented 30 years of medicinal use in Sweden had DER 6.5:1. Production of dry a extract with a fixed DER (without any range) is not techicaly possible. Thereforeit was decided in 2010 to extend the DER to 5.5-7.5:1, to cover other comparable preparations that were on the market at that time. The HMPC confirmed the MLWP proposal.
3. Non-Clinical Data
3.1. Overview of available pharmacological data regarding the herbal substance(s), herbal preparation(s) and relevant constituents thereof
Many pharmacological investigations were performed with extract made from 95% aerial parts and 5% roots of Echinacea purpurea. They are presented in the assessment report of the Echinacea purpurea herba (EMA /HMPC/48704/2014 Corr).
3.1.1. Primary pharmacodynamics
In vitro experiments
An ethanolic extract (strength of ethanol and DER not reported) of purple coneflower root enhanced phagocytosis by 33% in the granulocyte smear test at a concentration of 10-4 mg/ml. Aqueous and lipophilic fractions from the ethanolic extract showed immunostimulatory activity (Bauer et al., 1989).
Using an older human adult model of influenza vaccination, peripheral blood mononuclear cells were collected from subjects 6 months post-vaccination and stimulated in vitro with the two Type A influenza viruses contained in the trivalent 2004-2005 vaccine with a 50% ethanol tincture prepared from the roots of E. purpurea. Before being processed the roots had been stored under dry conditions for sixteen months. Cells were cultured for 48 hours; following incubation, supernatants were collected and assayed for IL-2, IL-10, and IFN-γ production, cytokines important in the immune response to viral infection. E. purpurea augmented IL-10 production, diminished IL-2 production, and had no effect on IFN-γ production. The results indicate that dried Echinacea roots stored for sixteen months maintain cytokine-modulating capacities (Senchina et al., 2006).
An extract of Echinacea purpurea roots (50% alcoholic tincture, DER 1:9 w/v) was tested for immunomodulation in rhinovirus-infected and uninfected epithelial cells. Since immune modulation has been reported for similar extracts, cytokine antibody arrays were used to investigate the changes in the pro-inflammatory cytokines and chemokines released from a cultured line of human bronchial epithelial cells exposed to rhinovirus 14 and the chemically characterized Echinacea extract. Virus infection stimulated the release of at least 31 cytokine-related molecules, including several important chemokines known to attract inflammatory cells. Most of these effects were reversed by simultaneous exposure to the Echinacea extract. Furthermore, a number of these cytokines were stimulated by the same Echinacea preparation in uninfected cells (Sharma et al., 2006).
The immunomodulatory properties of an Echinacea tincture from E. purpurea root (DER 1:9, ethanol strength: 50% V/V) after being stored at -20°C for 2 years was tested. The roots of other Echinacea species were tested separately for comparison. Two experimental techniques were employed using human peripheral blood mononuclear cells (PBMCs). In the first set of experiments, PBMCs were stimulated in vitro with tincture alone and assayed for proliferation and production of IL-10, IL-12, and
TNF-α. In the second set of experiments, subjects were immunized with influenza vaccine. PBMCs from vaccinated individuals were stimulated in vitro with the tincture and influenza virus; cytokine production (IL-2, IL-10, and IFN-γ was compared prevaccination and postvaccination. In the first experiments, E. purpurea stimulated only IL-10. In the second experiment, the tincture did not diminished influenza-specific IL-2, and did not influenced influenza-specific IL-10 or IFN-γ. (McCann et al., 2007).
The effects of Echinacea and several of its phytochemical components on NFκB expression by Jurkat cells (a human T-cell line) were investigated in vitro. In the absence of stimulation, Echinacea and its components exerted no significant effect on basal NFκB expression levels. In the presence of endotoxin lipopolysaccharide (LPS), NFκB expression was decreased. However, this decrease was significantly reversed by treatment with cichoric acid, an Echinacea root extract (prepared from both E. angustifolia and E. purpurea; 1:2 extraction solvent ethanol 60%) and the alkylamide fraction derived from this combination. For the phorbol myristate acetate stimulation of Jurkat cells, effects on NFκB expression were mixed. Depending on the concentration, cichoric acid and a 2,4-diene alkylamide significantly induced NFκB levels, whereas a 2-ene alkylamide caused a significant inhibition. In contrast, both the Echinacea and the mixed alkylamide fraction exerted no effect. The alkylamide results indicate that the two basic forms of these compounds present in Echinacea may have opposing effects. These opposing effects demonstrate the importance of knowledge, not only of the phytochemical make-up of a herbal preparation, but also of the actions of each component and the consequences of differing relative amounts in the preparation being investigated (Matthias et al., 2008).
Todd et al. (2015) evaluated the effects of a 75% ethanolic root extract of Echinacea purpurea, prepared in accord with industry methods, on cytokine and chemokine production from RAW 264.7 macrophage-like cells. It was found that the extract displayed dual activities; the extract could itself stimulate production of the cytokine TNF-α, and also suppress production of TNF-α in response to stimulation with exogenous lipopolysaccharide LPS. Liquid: liquid partitioning followed by normal-phase flash chromatography resulted in separation of the stimulatory and inhibitory activities into different fractions, confirming the complex nature of this extract. The role of alkylamides in the suppressive activity of this E. purpurea extract was also studied. The fractionation method concentrated the alkylamides into a single fraction, which suppressed production of TNF-α, CCL3, and CCL5; however fractions that did not contain detectable alkylamides also displayed similar suppressive effects. Alkylamides, therefore, likely contribute to the suppressive activity of the extract but are not solely responsible for that activity. From the fractions without detectable alkylamides, xanthienopyran was purified, a compound not previously known to be a constituent of the Echinacea genus. Xanthienopyran suppressed production of TNF-α suggesting that it may contribute to the suppressive activity of the crude ethanolic extract. The authors ascertain that ethanolic extracts prepared from E. purpurea plants grown under sterile conditions and from sterilized seeds, do not contain LPS and do not stimulate macrophage production of TNF-α, supporting the hypothesis that the macrophage-stimulating activity in E. purpurea extracts can originate from endophytic bacteria. The findings indicate that ethanolic E. purpurea extracts contain multiple constituents that differentially regulate cytokine production by macrophages.
It was reported that with the increasing popularity of herbal medicines, many people make their own Echinacea extracts at home and storing them at refrigerator (4°C) temperatures. A hypothesis is that Echinacea extracts made using homemade methods change in immunomodulatory efficacy with storage at 4°C over a 4-day period. Three extract types (50% ethanol tincture, cold water infusion, hot water infusion) from the roots of 5 different species (E. angustifolia, E. pallida, E. purpurea, E. sanguinea, E. tennesseensis) were prepared. Four in vitro immune assays (monocyte secretion of TNF- α, IL-10, and IL-12 and PBMC proliferation) using human blood was used to test extract efficacy at days 1 and 4 post-extraction. Two statistical analyses, traditional ANOVA and several statistical models
that account for endotoxin effects were used. Endotoxin was found to significantly impact immune outcomes only in 4-day old cold water infusions and not in all assays. Extracts showed the greatest stimulation in TNF-α assays. By extract type, 50% ethanol tinctures produced the most immune stimulation. By species, extracts from Echinacea angustifolia extracts were the most efficacious in the assays; extracts from Echinacea sanguinea showed the least activity overall (Senchina et al., 2005).
Similarities and differences in immune response among Echinacea species, which are commonly used to treat upper respiratory infections were compared and investigated. The investigation involved two components: acquisition of immunomodulatory data reported for the first time according to the authors, and combined phenetic analysis of these data along with previous reports. Experimental data were obtained by stimulating human PBMC in vitro with extracts from Echinacea spp. and assaying production of three cytokines (IL-1β, IL-2, and TNF-α). Phenetic analyses were employed to compare responses across the entire data set, including UPGMA (Unweighted Pair Group Method with Arithmetic Mean) and neighbor-joining methods. In the immune experiments conducted for this investigation, E. angustifolia, E. paradoxa, E. purpurea, E. simulata, and E. tennesseensis extracts prepared from roots significantly augmented IL-1β and TNF-α production, whereas no extracts significantly modulated IL-2. All phenetic methods produced similar dendrograms, revealing two species pairs (E. angustifolia + E. simulata and E. pallida + E. sanguinea) where both species cluster tightly and have similar immune- response profiles. These two species-pairs are maximally dissimilar from each other. The remaining species (E. paradoxa, E. purpurea, and E. tennesseensis) occupy intermediate positions in the dendrogram. The authors concluded that the results suggest that Echinacea spp. act heterogeneously on immune function (Senchina et al., 2008).
Alcaline-water extracts of Echinacea purpurea (plant part not reported) polysaccharide fractions with molecular weights in the range of 25000 to 500 000 and higher have been isolated, which, according to the granulocytes- and carbon clearance tests, showed significant immunostimulating activities. They stimulated the activity of mouse macrophages; this activation included enhanced secretion of interleukin-1 (IL-1). The isolated compounds belong to the group of water-soluble, acidic heteroglycanes (Wagner et al., 1984, Beuscher et al., 1990).
Purple coneflower root powders and various extracts obtained from the market (details not reported) showed a macrophage activating capacity. Extracts standardised to 4% of phenolic compounds (such as chlorogenic and cichoric acid) or to alkylamides were inactive with respect to induction of macrophage cytokine production (Rininger et al., 2000).
The research made by Benson et al. (2010) focused on defining the effects of Echinacea purpurea extracts in dendritic cells (DCs), which generate innate and adaptive immune responses. They hypothesized that E. purpurea extracts would enhance murine bone marrow-derived DC (BMDC) activation leading to increased immune responses. The fate and function of DCs that were obtained from C57Bl/6 mice was evaluated following 48h exposure to E. purpurea root and leaf extracts. The leaves were extracted with 75% ethanol, while the root extraction was aqueous. Flow cytometry revealed that the polysaccharide-rich root extract increased the expression of major histocompatibility complex (MHC) class II, CD86, and CD54 surface biomarkers whereas the alkylamide-rich leaf extract inhibited expression of these molecules. Production of IL-6 and TNF-alpha increased in a concentration- dependent manner with exposure to the root, but not leaf, extract. In contrast, the leaf but not root extract inhibited the enzymatic activity of cyclooxygenase-2. While both extracts decreased the uptake of ovalbumin by BMDCs, the leaf but not root extract inhibited the antigen-specific activation of naïve CD4(+) T cells from OT II/Thy1.1 mice. Collectively, these results suggest that E. purpurea can be immunostimulatory, immunosuppressive, and/or anti-inflammatory depending on the portion of the plant and extraction method.
Fast et al. (2015) describe the anti-inflammatory effect of a water extract of Echinacea purpurea roots (EPRW) that inhibited Pam3Csk4 stimulated production of TNFα by human monocytic THP-1 cells. The polyphenols and alkylamides typically found in Echinacea extracts were absent in EPRW suggesting that the anti-inflammatory component(s) was a polysaccharide. This anti-inflammatory activity was shown to be mediated by the phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway as chemical inhibition of PI3K abolished the EPRW anti-inflammatory effect. Demonstration of phosphorylation of Akt and ribosomal S6 proteins, downstream targets of PI3K confirmed EPRW-mediated activation of this pathway. This result suggests that non-alkylamide/non-polyphenolic phytochemicals from Echinacea may contribute in part to some of the anti-inflammatory therapeutic effects such as reduced severity of symptoms that have been observed in vivo in the treatment of upper respiratory tract infections with Echinacea. But low bioavailability of polysaccharides in humans is not taken into account by the author.
The study carried out by Pugh et al. (2013) determined total bacterial load within E. purpurea samples (aerial and root plant parts) and ranged from 6.4 × 10(6) to 3.3 × 10(8) bacteria/g of dry plant material. To estimate total bacterial load, a PCR-based quantification method that circumvents the problems associated with nonviable/nonculturable cells (which precludes using plate counts) or the coamplification of mitochondrial or chloroplast DNA with the use of universal bacterial primers (which precludes the use of qPCR) was developed. Differences in total bacterial load within Echinacea samples were strongly correlated with the activity (NF-κB activation in THP-1 cells) and content of bacterial lipopolysaccharides within extracts of this plant material. These results add to the growing body of evidence that bacteria within Echinacea are the main source of components responsible for enhancing innate immune function.
The study by Rizzello et al. (2013) aimed at investigating the capacity of selected lactic acid bacteria to enhance the antimicrobial, antioxidant and immune-modulatory features of E. purpurea with the prospect of its application as functional food, dietary supplement or pharmaceutical preparation.
E. purpurea suspension (5%, w/v) in distilled water, containing 0.4% (w/v) yeast extract, was fermented with Lactobacillus plantarum POM1, 1MR20 or C2, previously selected from plant materials. Chemically acidified suspension, without bacterial inoculum, was used as the control to investigate functional features. Echinacea suspension fermented with Lactobacillus plantarum C2 exhibited a marked antimicrobial activity towards Gram-positive and -negative bacteria. Compared to control, the water-soluble extract from Echinacea suspension fermented with Lactobacillus plantarum 1MR20 showed twice time higher radical scavenging activity. Almost the same was found for the inhibition of oleic acid peroxidation. The methanol extract from Echinacea suspension had inherent antioxidant features but the activity of extract from the sample fermented with strain 1MR20 was the highest. The antioxidant activities were confirmed on Balb 3T3 mouse fibroblasts. Lactobacillus plantarum C2 and 1MR20 were used in association to ferment Echinacea suspension, and the water-soluble extract was subjected to ultra-filtration and purification through RP-FPLC. The antioxidant activity was distributed in a large number of fractions and proportional to the peptide concentration. The antimicrobial activity was detected only in one fraction, further subjected to nano-LC-ESI-MS/MS. A mixture of eight peptides was identified, corresponding to fragments of plantaricins PlnH or PlnG. Treatments with fermented Echinacea suspension exerted immune-modulatory effects on Caco-2 cells. The fermentation with Lactobacillus plantarum 1MR20 or with the association between strains C2 and 1MR20 had the highest effect on the expression of TNF-α gene.
Purified polysaccharides (EPS) prepared from the herb and root of Echinacea purpurea are shown to strongly activate macrophages. Macrophages activated with these substances develop pronounced
extracellular cytotoxicity against tumour targets. The activation is brought about by EPS alone and is independent of any cooperative effect with lymphocytes. Also the production and secretion of oxygen radicals and interleukin-1 (IL-1) by macrophages is increased after activation with EPS. Cells of the macrophages lineage seem to be the main target for the action of these polysaccharides. EPS has no effect on T lymphocytes. B lymphocytes show a comparatively modest proliferation after incubation with E. purpurea EPS (Stimpel et al., 1984).
A high molecular weight fraction (Mr>10,000 D) containing polysaccharides and glycoproteins from purple coneflower root enhanced the proliferation of mouse spleen cells; stimulated the production of cytokines such as interferon (IFNα/β) in spleen cell cultures, and IL-1, interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) in mouse macrophage cultures; increased immunoglobulin M production and the number of antibody-producing cells, and increased nitric oxide (NO) production of macrophages (Beuscher et al., 1995, Bodinet, 1999). Incubation of this fraction with human monocytes also enhanced the production of IL-1, IL-6 and TNF-α (Bodinet, 1999).
Isolated alkamide dodeca-2Z,4E-diene-8,10-diynoic acid isobutylamide from E. purpurea and E. pallida roots exerted inhibition on lipopolysaccharide (LPS)-mediated activation of a murine macrophage line, RAW264.7 (Chen et al. 2005).
In vivo experiments
In contrast to the extensive body of research supporting the immunomodulatory effect of Echinacea preparations, some recent work has reported a lack of effect. No evidence of NK cell activity or antibody formation was found in studies involving rats fed various preparations of Echinacea, including an alcoholic extract of E. purpurea root and an alcoholic extract of the roots of E. angustifolia and E. pallida in their diet (South and Exon, 2001).
Production of the cytokines IL-1 and IL-6 in mice was enhanced by intravenous doses (50, 100 and 500 µg/animal) of a purified high molecular weight fraction containing glycoproteins and polysaccharides from purple coneflower root (Bodinet and Beuscher, 1991, Beuscher et al., 1995). Oral administration of this fraction to mice significantly enhanced antibody production in Peyer’splaque cells (Bodinet, 1999).
Using male Sprague-Dawley rats (425–475 g), a study was conducted to examine the immunomodulatory effects of preparations of Echinacea purpurea. Cichoric acid, polysaccharide and alkylamide fractions were obtained from Echinacea purpurea plants by water-ethanol extraction of the roots or the aerial parts. The fractions were purified to ca. 95% purity and were used to make 4 extracts in 50% ethanol containing its components cichoric acid, polysaccharides and alkylamides in different concentrations. The rats were gavaged orally with these preparations two times daily for 4 days. Phagocytic activity of alveolar macrophage was increased with increasing concentrations of the Echinacea components. A trend of increase in TNF-α and NO release by the alveolar macrophages following an in vitro stimulation with LPS was also evident. An enhanced release of cytokines (such as TNF-α and IFN-γ) in response to Echinacea components, was also apparent in rat’s spleen macrophage, but at higher concentrations. Among the components, alkylamides at the dose level of 12 mg/kg body weight/day significantly increased the phagocytic activity as well as phagocytic index of the alveolar macrophages. None of the components at any concentration had any effect on the release of TNF-α, IFN-γ and IL-2 by the splenocytes. These results suggest that the Echinacea preparations containing cichoric acid, polysaccharides and alkylamides are potentially effective in stimulating an in vivo, non- specific immune response in normal rats and that the alkylamides at a dose level of approximately 12
mg/kg body weight/day effectively stimulate alveolar macrophage function in healthy rats. The immunomodulatory effects of alkylamides appear to be more pronounced in lungs than in spleen (Goel et al., 2002a, Goel et al., 2002b).
Echinacea purpurea dry root powder (containing 1.5% total polyphenols, calculated as chlorogenic acid) increased the resistance of splenic lymphocytes to apoptosis; splenic lymphocytes were obtained from mice administered the Echinacea preparation orally at dosages of 30 or 100 mg/kg daily for
14 days (Di Carlo et al., 2003).
The debate is still on-going with respect to the efficacy of ingesting Echinacea purpurea preparation intermittently, continuously, or only at the beginning of an affliction. It was sought, therefore, to find out if mice, receiving dietary Echinacea daily (commercial purple coneflower root extract, extraction solvent not reported), throughout life, from youth until late middle-age, demonstrated any longevity/survival differences, and/or any differences in their various populations of immune/hemopoietic cells. Sustained and/or high levels of these cells are crucial for longevity. Some mice were maintained on a regular chow diet to which was added Echinacea purpurea daily
(2 mg/mouse), from puberty (7 week) until just beyond 13 months of age (late middle-age in mice). Control mice, identically housed and maintained, received identical chow without the herbal preparation. Mice consuming untreated diet had a 79% survival by 10 months of age, while those consuming Echinacea daily in the diet were still 100% alive by 10 months. At approximately 13 months of age, mice consuming untreated diet had a 46% survival rate while those consuming Echinacea, were 74% alive at this time. Moreover, the key immune cells, acting as the first line of defence against developing neoplasms in mice and humans, i.e. NK cells, were significantly elevated in absolute number both in their bone marrow production site, as well as in the major organ to which they traffic and function, i.e. the spleen. The cells of the myeloid/granulocyte lineages remained steadfastly at control levels in both the bone marrow and spleen in Echinacea-consuming mice. Thus, the authors concluded that it appears that regular intake of Echinacea may indeed be beneficial/prophylactic, if only for the reason that it maintains in an elevated state, NK cells, prime elements in immunosurveillance against spontaneous-developing tumours, a phenomenon which increases in frequency with progressive aging (Brousseau and Miller, 2005).
The research of Uluışık et al. (2012) determined the effect of ginseng and echinacea on the mRNA expression of IL-10, TNF-α, and TGF-β1 in healthy rats. Six-week-old male Fischer 344 rats (n= 48) were used. The animals were divided into three equal group: control; ginseng; echinacea. While the control group was fed a standard rat diet (Purina) ad libitum for a period of 40 days, the ginseng and echinacea groups animals received the same diet containing 0.5 g/kg of Panax ginseng root powder and 0.75 g/kg of E. purpurea root powder, respectively. Blood samples were obtained from 8 rats in each group after 20 and 40 days of treatment, and the mRNA expression of IL-10, TNF-α, and TGF-β1 was determined. After 20 days of treatment, the expression of IL-10 mRNA in the ginseng group was different from the control group (P< 0.05); however, after 40 days of treatment, there was no difference between the groups. There was no difference after 20 and 40 days of treatment between the groups with respect to the expression of TGF-β1 mRNA. After 20 days of treatment, the expression of
TNF-α mRNA in the echinacea group was higher (P< 0.05) than the control group. After 40 days of treatment, the expression of TNF-α mRNA was similar in all of the groups.
Barbour et al. (2015) evaluated an experimental Salmonella enteritidis (SE) bacterin and an indirect ELISA system to assess quantitatively the acquired immunity in Awassi ewes to the vaccine and/or E. purpurea dried roots. Four treatments of the ewes were included in the experimental design, with
6 ewes/treatment. The first treatment (T1) had the controls that were non-vaccinated and non-treated with E. purpurea. The T2 ewes were only treated with E. purpurea. The T3 and T4 ewes were
vaccinated at D1 (initiation of trial) and D10, while the T4 ewes were additionally administered the E. purpurea dried roots. Blood was collected from the jugular vein of all ewes at D1, D10, D21 and
D45. The construction of the vaccine and the ELISA are detailed within the manuscript. The ELISA was able to detect quantitatively the significant acquired primary and secondary immunity to the vaccine in T3 and T4 ewes, compared to their low level of background immunities at initiation of the experiment (p< 0.05). In addition, the ELISA detected the absence of seroconversion at all blood sampling times (p> 0.05) in T1 control ewes, and in the T2 ewes that were given only the (EP) (p> 0.05). ELISA was able to uncover the significant seroconversion of secondary immune response in T4 ewes at D21 compared to that at D10 (p< 0.05), and the absence of significant seroconversion of secondary response in T3 ewes. The study reports the need to supplement the vaccination by the experimental SE bacterin with daily oral intake of 250 mg of E. purpurea dried roots, effective the first vaccination day and up to 21 days, for obtaining a statistically significant seroconversion.
Oral administration of 0.45 mg/day of commercial purple coneflower root extract (extraction solvent not reported) to 7-week-old mice for 2 weeks resulted in a doubling of the number of NK cells and monocytes in the bone marrow, and in the spleen (Sun et al., 1999). Oral administration of the same amount of root extract to ageing mice (15-16 months old, with an average life span of 21 months) stimulated the production of new NK cells, leading to 30% increase in the absolute number of NK cells and a 20% increase in the total functional activity of NK cells in the spleen as measured by the lysis of lymphoma cells in vitro (Currier and Miller, 2000). Moreover, oral administration of the powdered root to mice injected with leukaemia cells increased their survival time compared to controls (Currier and Miller 2001). Powdered root also exhibited strong adjuvant effect on vaccination with inactivated leukaemia cells (Currier and Miller, 2002).
The combination preparation, comprising aqueous ethanolic extracts of Echinacea purpurea and E. pallida root, Baptisia tinctoria root and Thuja occidentalis herb, administered orally via the diet or drinking water to mice for 7 days enhanced the antibody response to sheep red blood cells (sRBC) (Bodinet and Freudenstein, 1999).
A phytopharmaceutical containing an extract of Echinacea purpurea and Glycyrrhiza glabra root was investigated for its suggested immunostimulating potential, using several in vitro tests and the in vivo carbon-clearance model in mice. In the in vitro phagocytosis test with human granulocytes, combination extract showed a 44-53% stimulating effect at a concentration of 100 µg/ml. Whereas in the chemoluminescence test at a concentration of 1.25 µg/ml, combination extract exhibited a moderate enhancing effect only, a remarkable stimulating activity (30-50%) was observed in the T- lymphocyte CD69 bioassay at a concentration of 100 µg – 1 µg/ml. The highest immunological efficacy could be assigned to as revealed by the in vivo carbon clearance model in mice. With RCt/RCc-values of 2.0, exhibited a very high carbon elimination rate at oral administration. Because the Echinacea and Glycyrrhiza monoextracts alone showed lower RCt/RCc-values (1.3-1.7), a potentiating synergistic effect of the extract mixture was postulated by the authors (Wagner and Jurcic, 2002).
El-Ashmawy et al. (2015) described the effect of Echinacea purpurea whole plant extract (extraction solvent 100% methanol) on the generation of immature dendritic cells (DCs) from monocytes, as well as its effect on DC differentiation. In addition, an in vivo experiment was conducted to investigate whether treatment of mice with extracts derived from E. purpurea has immunomodulatory effect on murine splenic DCs. Immature DCs were generated by incubating peripheral blood monocytes with cytokine cocktail (GM-CSF + IL-4) and matured by tumor necrosis factor-α (TNF-α). The cells were randomized to 5 groups to investigate E. purpurea effect in different stages. Phenotypic analysis of cell marker CD83-expressed on DCs was performed by flow cytometry. Mice were randomly divided into 3 groups; control, E. purpurea treated and E. purpurea-TNF-α treated group. The murine splenic DCs
were isolated and phenotyped for CD83 and CD11c by flow cytometry. Treatment of monocytes with E. purpurea prior to addition of the maturation factor TNF-α resulted in a significant decrease in the yield of DC expressing CD83. On the other hand, immature DCs generated in the culture in the presence of GM-CSF and IL-4, when treated simultaneously with E. purpurea and TNF-α, exhibited an insignificant change in the yield of CD83-expressing DCs compared with untreated control. The in vivo experiments showed that splenic DCs obtained from mice treated with E. purpurea with or without TNF-α did not exhibit significant changes in CD83 or CD11c compared with those obtained from control mice.
In vitro antimicrobial and antifungal activity
Antibacterial activity against Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and
Staphylococcus aureus has been demonstrated for a multi-herbal preparation containing Echinacea purpurea root extract, although it was stated that the observed antibacterial effects were most likely attributable to one of the ingredients, extract of onion (Westendorf, 1982).
Different commercialy available extracts of different species and different parts of Echinacea (including roots of E. purpurea ) and their fractions exhibited near UV-mediated phototoxic antifungal activity, measured by inhibition of the growth of Candida spp. and Saccharomyces cerevisiae; the activity was attributed primarily to ketoalkenes and ketoalkynes (Binns et al., 2000).
Antifungal activity was tested against Cryptococcus neoformans, two Candida albicans isolates (D10 and CN1A), Trichophyton tonsurans, T. mentagrophytes, Microsporum gypseum and Pseudallescheria boydii. Root extracts (extraction solvent 95 % ethanol, DER 1:10) of eight Echinacea taxa, including E. purpurea showed antifungal activity against most of the pathogenic fungi (Merali et al., 2003).
In vitro antiviral activity
Using mouse fibroblasts it was demonstrated that incubation with methanolic and aqueous extract of Echinacea purpurea root resulted in resistance to influenza A2, herpes, and vesicular stomatitis virus infection for 24 hours (Wacker and Hilbig, 1978).
A high molecular weight fraction (Mr >10,000 D) containing polysaccharides and glycoproteins from purple coneflower root exhibited antiviral activity against Herpes simplex virus (HSV) and influenza virus (Beuscher et al., 1995).
A decoction and a 30% ethanolic extract of purple coneflower root inhibited the propagation of ECHO9 Hill virus in monkey kidney cell cultures (Skwarek et al., 1996).
Extracts of 8 taxa of the genus Echinacea were found to have antiviral activity against HSV Type I in vitro when exposed to visible and UV-A light. n-Hexane extracts of roots containing alkenes and amides were more active in general than ethyl acetate extracts containing caffeic acids. The most potent inhibitors of HSV were E. pallida var. sanguinea crude (70 % ethanol) inflorescence extract (MIC = 0.026 mg/ml), cichoric acid (MIC = 0.045 mg/ml) and E. purpurea n-hexane root extract (MIC = 0.12 mg/ml) (Binns et al., 2002).
In vitro anti-inflammatory activity
Another study determined whether extracts and isolated alkylamides from E. purpurea would be useful for prevention of the inflammatory response that accompanies infections with H1N1 influenza A. Seventeen extracts and 4 alkylamides were tested for the ability to inhibit production of cytokines, chemokines, and PGE2 from RAW 264.7 macrophage-like cells infected with the H1N1 influenza A strain PR/8/34. The alkylamides undeca-2Z,4E-diene-8,10-diynic acid isobutylamide, dodeca-
2E,4E,8Z,10E/Z-tetraenoic acid isobutylamide, dodeca-2E,4E-dienoic acid isobutylamide, and undeca- 2E-ene-8,10-diynoic acid isobutylamide suppressed production of TNF-α and PGE2 from infected cells. Dodeca-2E,4E-dienoic acid isobutylamide was especially effective at inhibiting production of these mediators and also strongly inhibited production of G-CSF, CCL2/MCP-1, CCL3/MIP-1α and CCL5/RANTES. In contrast, the ethanol extracts (75%), which were prepared from dormant roots of E. purpurea grown in different locations throughout North Carolina, displayed a range of effects from suppression to stimulation of mediator production. Precipitation of the extracts with ethanol removed the stimulatory activity, however, even after precipitation; many of the extracts did not display any suppressive activity. Analysis of the extracts revealed slight variations in concentration of alkylamides, caftaric acid, and cichoric acid, but the activity of the extracts did not strongly correlate with concentrations of these compounds (Cech et al., 2010).
In vivo anti-inflammatory activity
The anti-inflammatory and wound healing activities of echinacoside, compared with the ones of the total dry ethanolic root extract of Echinacea purpurea and E. pallida, were examined in rats, after topical application of gel containing 100 mg/ml of the extract. The tissues of the treated animals were evaluated after 24, 48 and 72 hours treatment and excised for histological observation at the end of the experiment. Results confirm the good anti-inflammatory and wound healing properties of E. pallida and of its constituent echinacoside, with respect to E. purpurea and control (E. purpurea was more effective over the first 24 hours but inferior at 48-72 hours). This activity probably resides in the antihyaluronidase activity of echinacoside (Speroni et al., 2002).
5-lipoxygenase-inhibiting activity of root extracts (extraction solvent 95 % ethanol, DER 1:10) of five wild and three commercially used species of the genus Echinacea were investigated to characterise anti-inflammatory activity of Echinacea. The inhibition of the 5-lipoxygenase (5-LOX) enzyme of the arachadonic acid pathway was determined by high-performance liquid chromatography (HPLC) detection of a direct metabolic product (LTB4) of 5-LOX derived from stimulated rat basophilic cells. Root extracts of the three commercial species of Echinacea (E. purpurea, E. pallida var. angustifolia, E. pallida var. pallida) inhibited the 5-LOX enzyme (Merali et al., 2003).
Inhibition of prostaglandin E(2) (PGE(2)) production in LPS-stimulated RAW264.7 mouse macrophage cells was assessed with an enzyme immunoassay following treatments with Echinacea extracts (extraction solvent: ethanol (70, 95, or 100%), water, chloroform (100%), hexane (100%), or sequential extractions) or synthesized alkamides. Results indicated that ethanol extracts diluted in media to a concentration of 15 µg/ml from the roots of E. angustifolia, E. pallida, E. simulata, and E. sanguinea significantly inhibited PGE2 production. In further studies, PGE2 production was significantly reduced by all synthesized alkamides assayed at 50 µM, by Bauer alkamides 8, 12A analogue, and 14, Chen alkamide 2, and Chen alkamide 2 analogue at 25 µM and by Bauer alkamide 14 at 10 µM. Cytotoxicity did not play a role in the noted reduction of PGE2 production in either the Echinacea extracts or synthesized alkamides. HPLC analysis identified individual alkamides present at concentrations below 2.8 µM in the extracts from the six Echinacea species (15 µg/ml crude extract). Because active extracts contained <2.8 µM of specific alkamide and the results showed that synthetic alkamides must have a minimum concentration of 10 µM to inhibit PGE2, it is likely that alkamides may contribute toward the anti-inflammatory activity of Echinacea in a synergistic or additive manner (LaLone et al., 2007).
Alcohol extracts from the roots (sequential extraction wtih 100% ethanol, 95% ethanol, chloroform and hexane, followed by solvent evaporation and dissolving in 95 % ethanol) of E. angustifolia, E. pallida, and E. purpurea, were investigated for immunomodulating properties. The three Echinacea
species demonstrated a broad difference in concentrations of individual lipophilic amides and hydrophilic caffeic acid derivatives. Mice were gavaged once a day (for 7 days) with one of the Echinacea extracts (130 mg/kg) or vehicle and immunized with sheep red blood cells (sRBC) 4 days prior to collection of immune cells for multiple immunological assays. The three extracts induced similar, but differential, changes in the percentage of immune cell populations and their biological functions, including increased percentages of CD49+ and CD19+ lymphocytes in spleen and NK cell cytotoxicity. Antibody response to sRBC was significantly increased equally by extracts of all three Echinacea species. Concanavalin A-stimulated splenocytes from E. angustifolia– and E. pallida-treated mice demonstrated significantly higher T cell proliferation. In addition, the Echinacea treatment significantly altered the cytokine production by mitogen-stimulated splenic cells. The three herbal extracts significantly increased IFN-α production, but inhibited the release of TNF-γ and IL-1β. Only E. angustifolia– and E. pallida-treated mice demonstrated significantly higher production of IL-4 and increased IL-10 production. Taken together the authors concluded thatthese findings demonstrated that Echinacea is a wide-spectrum immunomodulator that modulates both innate and adaptive immune responses. In particular, E. angustifolia or E. pallida may have more anti-inflammatory potential (Zhai et al., 2007a).
The effect of the same alcohol extracts as in previous paragraph on the production of inflammatory mediators (nitric oxide (NO), TNF-α and IL-1β) in both LPS-stimulated RAW264.7 macrophages in vitro and murine peritoneal exudate cells (PECs) in vivo were investigated. As macrophages produce these inflammatory mediators in response to pathogenic infection, parallel cultures of macrophages were studied for phagocytosis and intracellular killing of Salmonella enterica. E. pallida and E. purpurea in vitro inhibited NO production and TNF-α release in a dose-dependent manner. RAW264.7 cells treated with E. angustifolia or E. purpurea showed decreased killing over 24 h, although E. angustifolia enhanced bacterial phagocytosis. Upon bacterial infection, RAW264.7 cells produce high levels of NO; however, an Echinacea-mediated decrease in NO production was observed. Echinacea alcohol extracts administered orally at 130 mg/kg per day for seven days had a weak effect on NO production and phagocytosis by LPS-stimulated PECs. The results indicated that all Echinacea species significantly decreased inflammatory mediators in vitro, however, only E. angustifolia and E. purpurea reduced bacterial killing. Oral administration of Echinacea alcohol extracts did not adversely affect the development and anti-bacterial function of inflammatory PECs in vivo; however, NO production was decreased during bacterial infection of PECs (Zhai et al., 2007b).
Polyunsaturated isobutylamides have been shown to exert anti-inflammatory activity in the 5- lipoxygenase assay (Wagner et al. 1989, Müller-Jakic et al. 1994). A fraction from purple coneflower root consisting of ten polyunsaturated isobutylamides had an inhibitory effect on 5-lipoxygenase of 92.5% at 60 µM (calculated for a mean relative molecular mass of 220) (Wagner et al. 1989).
A study made by Hou et al. (2010), demonstrates that the three most used medicinal Echinacea species, E. purpurea, E. pallida, and E. angustifolia, can be classified by the distribution and relative content of metabolites. Mixed alkamides and the major component, dodeca-2E,4E,8Z,10Z(E)- tetraenoic acid isobutylamides, were isolated from E. purpurea root extracts for further bioactivity elucidation. In macrophages, the alkamides significantly inhibited cyclooxygenase 2 (COX-2) activity and the lipopolysaccharide-induced expression of COX-2, inducible nitric oxide synthase and specific cytokines or chemokines [i.e., TNF-α, interleukin (IL)-1α, IL-6, MCP-1, MIP-1β] but elevated heme oxygenase-1 protein expression. Cichoric acid, however, exhibited little or no effect. The results of high-performance liquid chromatography/electron spray ionization/mass spectrometry metabolite profiling of alkamides and phenolic compounds in E. purpurea roots showed that specific compound contents changed under certain post-harvest or abiotic treatment.
The study of Hou et al. (2011) was about the anti-inflammatory and hepatoprotective effect of the major alkamides dodeca-2E,4E,8Z,10Z(E)-tetraenoic acid isobutylamides (Alk-8/9), isolated from E. purpurea roots (in the article it is not specified how they are isolated), against acute fulminant
hepatitis induced by lipopolysaccharide/D-galactosamine (LPS/D-GalN) in mice. The results show that Alk-8/9 dose-dependently induced heme oxygenase (HO)-1 protein expression in LPS-stimulated murine macrophages that was likely regulated by the JNK-mediated pathway through increasing SAPK/JNK phosphorylation, c-jun protein expression, and phosphorylation, and transcription factor AP- 1 binding consensus DNA activity. The HO-1 inhibitor or CO scavenger significantly reversed the inhibitory effect of Alk-8/9 on TNF-α expression, whereas N-acetyl-L-cysteine was observed to reduce Alk-8/9-induced HO-1 expression in LPS-treated macrophages. Furthermore, Alk-8/9 markedly induced c-jun and HO-1 protein expression and suppressed serum aminotransferase activities, TNF-α expression, and hepatocyte damage in liver tissues of LPS/d-GalN-treated mice.
Echinacea purpurea (dry root powder) and Hypericum perforatum L. were evaluated for their anti- inflammatory activity against carrageenan-induced paw oedema in mice. Each drug was administered orally to mice at 30 and 100 mg/kg, twice daily. Only the higher dose significantly inhibited, time dependently, the formation of oedema, evaluated as area under the curve (Echinacea P< 0.01; Hypericum P< 0.05). Western blot analysis showed that in vivo treatment with these extracts could modulate lipopolysaccharide (LPS) and IFN-γ induced cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression in peritoneal macrophages. In particular, treatment with 100 mg/kg Hypericum inhibited both iNOS and COX-2 expression, whereas treatment with 100 mg/kg Echinacea down-regulated only COX-2 expression. The present study suggests that the anti-inflammatory effect of these extracts could be in part related to their modulation of COX-2 expression (Raso et al. 2002). Further exploration suggested that the observed effect may be due to down-regulation of COX-2 expression by the Echinacea preparation. In vitro inhibition of COX-1 and, to lesser extent, COX-2 has been described to alkamides isolated from E. purpurea roots (Clifford et al. 2002).
Table 4: Overview of the main non-clinical data/conclusions
3.1.2. Secondary pharmacodynamics
In vitro antioxidant activity
The protective effect of caffeoyl derivatives (echinacoside, chlorogenic acid, cichoric acid, cynarine, and caffeic acid, typical constituents of Echinacea species) on the free radical-induced degradation of Type III collagen has been investigated. The results indicate that this representative class of polyphenols of Echinacea species protects collagen from free radical damage through a scavenging effect on reactive oxygen species and/or C-, N-, S-centered secondary radicals, and provides an indication for the topical use of extracts from Echinacea species for the prevention/treatment of photodamage of the skin by UVA/UVB radiation, in which oxidative stress plays a crucial role (Maffei Facino et al., 1995).
In the study of methanol extracts of freeze-dried roots of Echinacea species (E. angustifolia, E. pallida, and E. purpurea) on free radical scavenging capacities and antioxidant activities it was demonstrated that the mechanisms of antioxidant activity of extracts derived from Echinacea roots included free radical scavenging and transition metal chelating (Hu and Kitts, 2000).
Alcoholic extracts of the roots and leaves of three Echinacea species (E. purpurea, E. angustifolia and E. pallida) were found to have antioxidant properties in a free radical scavenging assay and in a lipid peroxidation assay. Cichoric acid and verbascoside predominated in extracts of E. purpurea (Sloley et al., 2001).
The radical scavenging activity of Echinacea methanolic extracts was evaluated in vitro with a spectrophotometric method based on the reduction of an alcoholic DPPH (1, 1diphenyl-2-picryl hydrazyl) radical solution at 517 nm in the presence of a hydrogen donating antioxidant. As for pure compounds, echinacoside had the highest capacity to quench DPPH radicals (EC50 = 6.6 µM), while caftaric acid had the lowest (EC50 = 20.5 µM). The average EC50 values for E. purpurea, E. pallida and E. angustifolia were 134, 167 and 231 µg/ml, respectively. The radical scavenging activity of Echinacea root extracts reflected their phenolic composition (Pellati et al., 2004).
After extraction, fractionation, and isolation, the antioxidant activity of three extracts, one alkamide fraction, four polysaccharide-containing fractions, and three caffeic acid derivatives from Echinacea purpurea root was evaluated by measuring their inhibition of in vitro Cu(II)-catalyzed oxidation of human low-density lipoprotein. The order of antioxidant activity of the tested substances was cichoric acid > echinacoside > derivative II > caffeic acid > rosmarinic acid > derivative I. Among the extracts the 80% aqueous ethanolic extract exhibited a 10 times longer lag phase prolongation (LPP) than the 50% ethanolic extract, which in turn exhibited a longer LPP than the water extract. Following ion- exchange chromatography of the water extract, the majority of its antioxidant activity was found in the latest eluted fraction (H2O-acidic 3). The antioxidant activity of the tested Echinacea extracts, fractions, and isolated compounds was dose-dependent. Synergistic antioxidant effects of Echinacea constituents were found when cichoric acid (major caffeic acid derivative in E. purpurea) or echinacoside (major caffeic acid derivative in E. pallida and E. angustifolia) were combined with a natural mixture of alkamides and/or water extract containing the high molecular weight compounds. This contributes to the hypothesis that the physiologically beneficial effects of Echinacea are exerted by the multitude of constituents present in the preparations (Dalby-Brown et al., 2005).
The antioxidant activity of extracts of the stems, leaves, and roots of Echinacea purpurea was compared with the antioxidant activity of purified cichoric acid and alkamides, both constituents of E. purpurea. The antioxidant activity was determined using different methods: effect on oxygen consumption rate of a peroxidating lipid emulsion, and scavenging of radicals, i.e. DPPH, measured by two different techniques. The efficacy of the extracts in the reaction with DPPH correlated well with the amount of cichoric acid present in the various extracts. The alkamides alone showed no antioxidant
activity in any of the tests. Alkamides present in the extract increased, however, the antioxidative effect of cichoric acid in the peroxidating lipid emulsion. The activity was further compared with that of rosmarinic acid, a well-characterised antioxidant, and the extracts as well as cichoric acid were found to be efficient scavengers of radicals with an activity comparable to that of rosmarinic acid. Cichoric acid was found to have a stoichiometric factor of 4.0 in scavenging DPPH and to react in a second- order reaction with DPPH with a rate constant of 40 L/mol/s at 25°C in methanol (Thygesen et al., 2007).
Fibroblast-populated collagen lattice was used to study the influence of purple coneflower extracts on the collagen contracting ability of C3H10T1/2 mouse fibroblasts. An ethanolic extract (65% V/V) of purple coneflower root showed a dose-dependent inhibition of collagen gel contraction when added at the time of preparation of the gel. A corresponding amount of ethanol showed no influence. With increase of elapsed time between gel preparation and addition of extract, there was less inhibition of elongation of fibroblasts and of the processes leading to collagen linking. No effect was observed when the extract was added one hour after gel preparation (Zoutewelle and Van Wijk, 1990).
Serial dilutions of 21 commercial ethanolic herbal extracts and tinctures, and 13 related pure plant compounds have been analyzed for their in vitro cytochrome P450 3A4 (CYP3A4) inhibitory capability via a fluorometric microtitre plate assay. Roughly 75% of the commercial products and 50% of the pure compounds showed significant inhibition of CYP3A4 metabolite formation. Echinacea purpurea root extract showed moderate inhibitory activity (IC50 > 5% and < 10% full strength) (Budzinski et al., 2000).
In the study of the effect of Echinacea purpurea root extract (prepared with 50% aqueous ethanol, DER was not specified) on the weight of prostates in rats as well as on alterations of histological structure and separate blood cells with 3-month old male Wistar rats, it was observed a significantly important decrease of prostate weight of investigated rats, an increase in the number of lymphocytes as well as the alterations of histological structures after using Echinacea extract for 8 weeks (Skaudickas et al., 2003).
The effect of Echinacea purpurea extract (prepared with 50% aqueous ethanol, DER was not given) on a rat testicle and epididymis was examined, the mass of these organs was determined, the proportion between the mass of the organ and the mass of a body was calculated, the changes in histological structures were evaluated in the study with the Wistar line 3-month old male rats. The histological structural changes were traced after 4 weeks of using the preparation; however they became more obvious after 8 weeks. Results of the study enabled to determine statistically significant reduction in the percentage of a testicle and the body mass, as well as changes in histological structures after 8 weeks of consuming extract of E. purpurea (Skaudickas et al., 2004).
It was shown that the alkylamides dodeca-2E,4E,8Z,10Z-tetraenoic acid isobutylamide (A1) and dodeca-2E,4E-dienoic acid isobutylamide (A2) bind to the CB2 receptor more strongly than the endogenous cannabinoids. Molecular modelling suggests that alkylamides bind in the solvent- accessible cavity in CB2, directed by H-bonding and π–π interactions. In a screen with 49 other pharmacologically relevant receptors, it could be shown that A1 and A2 specifically bind to CB2 and CB1. A1 and A2 elevated total intracellular Ca2+ inCB2-positive but not in CB2-negative promyelocytic HL60 cells, an effect that was inhibited by the CB2 antagonist SR144528. At 50 nM A1, A2, and the endogenous cannabinoid anandamide (CB2 Ki >200 nM) up-regulated constitutive IL-6 expression in human whole blood in a seemingly CB2-dependent manner. A1, A2, anandamide, the CB2 antagonist SR144528 (Ki <10 nM), and also the non-CB2-binding alkylamide undeca-2E-ene-8,10-diynoic acid isobutylamide all significantly inhibited LPS-induced TNF-α, IL-1β, and IL-12p70 expression (5–500
nM) in a CB2-independent manner. Alkylamides and anandamide also showed weak differential effects on anti-CD3- versus anti-CD28-stimulated cytokine expression in human whole blood. Overall, alkylamides, anandamide, and SR144528 potently inhibited LPS-induced inflammation in human whole blood and exerted modulatory effects on cytokine expression, but these effects are not exclusively related to CB2 binding (Raduner et al., 2006).
Potential in vitro cytotoxic and pro-apoptotic properties of hexanic root extract of the three medicinal
Echinacea (Asteraceae) species (E. pallida (Nutt.) Nutt., E. angustifolia DC. var. angustifolia, E. purpurea (L.) Moench) were studied on the human pancreatic cancer MIA PaCa-2 and colon cancer COLO320 cell lines. The authors concluded that it was demonstrated, for the first time, that all the three species reduced cell viability in a concentration- and time-dependent manner (Chicca et al., 2007).
The n-hexane extracts of the roots of three medicinally used Echinacea species exhibited cytotoxic activity on human cancer cell lines. Cytotoxic effects were assessed on human pancreatic MIA PaCa-2 and colonic COLO320 cancer cell lines. Cell viability was evaluated by the WST-1 assay and apoptotic cell death by the cytosolic internucleosomal DNA enrichment and the caspase 3/7 activity tests (Chicca et al., 2008).
One likely mode of action is that alkamides from Echinacea bind to cannabinoid type 2 (CB2) receptors and induce a transient increase in intracellular Ca2+. The study of E. purpurea root extracts and constituents as potential regulators of intracellular Ca2+ levels made by Wu et al. (2010) shows that unidentified compounds from Echinacea purpurea induce cytosolic Ca2+ elevation in non-immune- related cells, which lack CB2 receptors and that the Ca2+ elevation is not influenced by alkamides. The data indicate that as yet unidentified constituents from Echinacea stimulate an IP3 receptor and phospholipase C mediation of cytosolic Ca2+ levels in non-immune mammalian cells. This pathway is distinct from that induced in immune associated cells via the CB2 receptor.
Multiple chromatographic separations of the CHCl3-soluble extract of the roots of Echinacea purpurea led to the isolation of 19 compounds. Four natural products, three alkamides and nitidanin diisovalerianate, were identified, and five further compounds were detected for the first time in this species. Additionally, 10 known Echinacea purpurea metabolites were isolated. The bioactivity of the isolated compounds was studied in [³⁵S] GTPγS-binding experiments performed on rat brain membrane preparations. Both partial and inverse agonist compounds for cannabinoid (CB1) receptors were identified among the metabolites, characterized by weak to moderate interactions with the G- protein signaling mechanisms. The G-protein-modulating activities of the Echinacea compounds are rather far from the full agonist effects seen with the CB1 receptor agonist reference compound arachidonyl-2′-chloroethylamide (ACEA). However, upon coadministration with ACEA, a number of them proved capable of inhibiting the stimulation of the pure agonist, thereby demonstrating cannabinoid receptor antagonist properties (Hohmann et al., 2011).
The study made by Shin et al. (2014) was conducted to investigate the effects of an ethanol extract of Echinacea purpurea root and herb material and its constituents on the insulin-induced adipocyte differentiation of 3T3-L1 preadipocytes. When adipocyte differentiation was induced with insulin plus 3- isobutyl-1-methylxanthine and dexamethasone, the accumulation of lipid droplets and the cellular triglyceride content were significantly increased by Echinacea purpurea. The expressions of PPARγ and C/EBPα in adipocytes treated with Echinacea purpurea were gradually increased as compared with control cells. Fat accumulation and triglyceride content of adipocytes treated with dodeca-2(E),4(E)- dienoic acid isobutylamide were significantly increased as compared with control cells. The expressions of PPARγ and C/EBPα in adipocytes treated with dodeca-2(E),4(E)-dienoic acid isobutylamide were significantly higher than in control cells. These results suggest Echinacea purpurea promotes the
adipogenesis that is partially induced by insulin and that dodeca-2(E),4(E)-dienoic acid isobutylamide appears to be responsible for enhanced adipocyte differentiation.
The purpose of the study carried out by Kotowska et al. (2014) was to identify the bioactive compounds responsible for the potential antidiabetic effect of the dichloromethane extract of E. purpurea roots using a bioassay-guided fractionation approach. Two novel isomeric dodeca-
2E,4E,8Z,10E/Z-tetraenoic acid 2-methylbutylamides together with two known C12-alkamides and α- linolenic acid were isolated from the active fractions. The isomeric C12-alkamides were found to activate peroxisome proliferator-activated receptor γ, to increase basal and insulin-dependent glucose uptake in adipocytes in a dose-dependent manner, and to exhibit characteristics of a peroxisome proliferator-activated receptor γ partial agonist.
3.1.3. Safety pharmacology
No data available.
3.1.4. Pharmacodynamic interactions
No data available.
There are only a few publications where pharmacological tests were performed with preparations related to the Echinacea purpurea roots’ preparations of the monograph. In most articles extracts prepared with 50% ethanol were tested, but the monograph describes the extract prepared with 45% ethanol. This does not present an issue regarding plausibility of the efficacy of the preparations concerned since a comparable composition of the extract is expected with so small difference in ethanol concentration as extraction solvent.
In many experiments concentrations are not available in the published reports. However, all researches refer to potential effects on different immunological parameters which indicate immunomodulatory effect.
The data obtained from other preparations differ, but show in most cases positive immunomodulatory effects.
Anti-inflammatory effects are described in several in vitro and in vivo experiments, but they were observed with preparations which are not comparable to the preparations of the monograph.
According to the literature both the immunomodulatory and the anti-inflammatory effects are attributed mainly to alkamides. The mechanism of action might be the inhibition of COX-1, COX-2 and 5-LO.
Less data are available for antibacterial, antiviral (mainly HSV and influenza virus) and antifungal effects. The data available allow only very limited conclusions on the contribution of the observed effects to the plausibility of the therapeutic effects of the preparations of the monograph.
3.2. Overview of available pharmacokinetic data regarding the herbal substance(s), herbal preparation(s) and relevant constituents thereof
Absorption, distribution, metabolism, elimination
Studies of transport of alkamides trough a cultured monolayer of colonic cells were performed on human adenocarcinoma colonic cell line Caco-2 (ATCC) as a model to assess the epithelial transport of dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamides. 30 minutes after apical loading of 25 µg/ml, about 15% of these alkamides were detectable on the basolateral side. Close monitoring of the transport during 6 hours revealed a nearly complete transport to the basolateral side after 4 hours and no significant metabolism was observable. Transport experiments performed at 4 °C showed only a slight decrease in transport, which is a strong hint that dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamides cross biological membranes by passive diffusion. Nearly the same results were obtained after preincubation of the Caco-2 cells with LPS or phorbol 12-myristate-13-acetate to mimic an inflammatory status. These results support the assumption that the alkamides can be easily transported from the intestine and hence may contribute to the in vivo effects of Echinacea preparations (Jager et al., 2002).
Transport of 12 alkamides and 5 caffeic acid conjugates from a product which contains 60% ethanol extract of E. angustifolia root (200 mg/ml) and E. purpurea root (300 mg/ml) was studied on Caco-2 monolayers. Almost all of the caffeic acid conjugates permeated poorly through the Caco-2 monolayers: their uptake was no better than that of control (mannitol). By contrast, both 2,4-diene and 2-ene alkamides readily diffused through the monolayers. These findings suggest that alkamides would be bioavailable following oral administration (Matthias et al., 2004).
The metabolism by human liver microsomes of the alkylamide components from an Echinacea preparation as well as that of pure synthetic alkylamides was investigated. No significant degradation of alkylamides was evident in cytosolic fractions. Time- and NADPH-dependent degradation of alkylamides was observed in microsomal fractions suggesting they are metabolised by cytochrome P450 (CYP450) enzymes in human liver. There was a difference in the susceptibility of 2-ene and 2,4- diene pure synthetic alkylamides to microsomal degradation with (2E)-N-isobutylundeca-2-ene-8,10- diynamide (1) metabolised to only a tenth the extent of (2E,4E,8Z,10Z)-N-isobutyldodeca-2,4,8,10- tetraenamide (3) under identical incubation conditions. Markedly less degradation of 3 was evident in the mixture of alkylamides present in an ethanolic Echinacea extract, suggesting that metabolism by liver P450s was dependent both on their chemistry and the combination present in the incubation. Co- incubation of 1 with 3 at equimolar concentrations resulted in a significant decrease in the metabolism of 3 by liver microsomes. This inhibition by 1, which has a terminal alkyne moiety, was found to be time- and concentration-dependent, and due to a mechanism-based inactivation of the P450s. Alkylamide metabolites were detected and found to be the predicted epoxidation, hydroxylation and dealkylation products. These findings suggest that Echinacea may affect the P450-mediated metabolism of other concurrently ingested pharmaceuticals (Matthias et al., 2005a).
The study made by Ardjomand-Woelkart et al. (2011) assessed the absolute and relative bioavailabilities of dodeca-2 E,4 E,8 Z,10 E/ Z-tetraenoic acid isobutylamides (tetraenes), the main bioactive constituents in Echinacea, administered as pure compounds or in the form of an Echinacea purpurea root extract preparation (extracted with 60 % ethanol) in rats. Tetraenes were administered orally by gavage or intravenously in a dose of 0.75 mg/kg. The extract was administered orally in a dose of 158.6 mg/kg which corresponds to the same amount of tetraenes. Pharmacokinetic parameters of tetraenes were calculated by non-compartmental analysis. Mean dodeca-2 E,4 E,8 Z,10 E/ Z- tetraenoic acid isobutylamide dose-normalized plasma area under the concentration-time curve (AUC – ∞/dose) was 3.24 ± 0.32 min · ng/ml/µg and 0.95 ± 0.16 min · ng/ml/µg after iv and oral administrations, respectively, and 1.53 ± 0.18 min · ng/ml/µg after oral administration of the Echinacea root extract. The absolute oral bioavailability of dodeca-2 E,4 E,8 Z,10 E/ Z-tetraenoic acid isobutylamides was 29.2 ± 2.3 %, which was increased to 47.1 ± 7.2 % (1.6-fold) by administration of the Echinacea extract. Administration of an Echinacea extract increased blood exposure with no impact
on Cmax, but prolonged the elimination half-life to 123.3 ± 15.7 min in comparison to 35.8 ± 6.5 min after administration of the pure dodeca-2 E,4 E,8 Z,10 E/ Z-tetraenoic acid isobutylamides.
The six commonly used trade herbal products, St. John’s wort, common valerian, common sage, Ginkgo biloba, Echinacea purpurea and horse chestnut, and ethanol, were investigated for their in vitro inhibitory potential of cytochrome P450 2D6 (CYP2D6)-mediated metabolism. Herbal components were extracted from commercially available products in a way that ensured the same composition of constituents in the extract as in the original trade products. c-DNA baculovirus expressed CYP2D6 was used with dextromethorphan as substrate. Quinidine was included as a positive control inhibitor. A validated HPLC methodology was used to quantify the formation of dextrorphan (product of dextromethorphan O-demethylation). Ethanol showed a biphasic effect on CYP2D6 metabolism, increasing initially the CYP2D6 activity with 175% of control up to a concentration of 1.1%, where after ethanol linearly inhibited the CYP2D6 activity. All the investigated herbs inhibited CYP2D6 activity to some extent, but only St. John’s wort, common sage and common valerian were considered possible candidates for in vivo clinically significant effects. They showed IC50 values of 0.07 +/- 7 x 10(-3) mg/ml, 0.8 +/- 0.05 mg/ml and 1.6 +/- 0.2 mg/ml, respectively. St. John’s wort inhibited CYP2D6- mediated metabolism in an uncompetitive manner, while common valerian and common sage in a non- competitive manner demonstrated interherb differences in inhibition patterns and differences when compared to the more homogenous competitive inhibitor quinidine. Common valerian was the only herb that showed a mechanistic inhibition of CYP2D6 activity and attention should be paid to a possible toxicity of this herb (Hellum and Nilsen, 2007).
The n-hexane root extracts from Echinacea pallida, E. angustifolia and E. purpurea were evaluated for inhibition of the multidrug transporter P-glycoprotein (Pgp) activity, the product of the ABCB1 gene, involved in cancer multidrug resistance (MDR) and in herb-drug or drug-drug interactions. The biological assay was performed using the human proximal tubule HK-2 cell line that constitutively expresses ABCB1. The n-hexane extracts of all three species reduced the efflux of the Pgp probe calcein-AM from HK-2 cells two-fold in a concentration-dependent manner, and E. pallida was found to be the most active species. For the first time, two polyacetylenes and three polyenes, isolated from the n-hexane extract of E. pallida roots by a bioassay-guided fractionation, were found to be able to reduce Pgp activity. Pentadeca-(8Z,13Z)-dien-11-yn-2-one was the most efficient compound, being able to decrease the calcein-AM efflux about three-fold with respect to the control at 30 µg/ml (Romiti et al., 2008).
Assessor’s overall conclusions on pharmacokinetics
In pharmacokinetic studies only alkamides and caffeic acid conjugates were investigated. It was shown that alkamides (in contrast with caffeic acid conjugates) readily diffuse through the monolayers of Caco-2 cells. This supports the assumption that the alkamides can be easily transported from the intestine and hence may contribute to the in vivo effects of Echinacea preparations. Administration of an Echinacea purpurea root extract increased blood exposure with no impact on Cmax, but prolonged the elimination half-life after administration of the pure dodeca-2 E,4 E,8 Z,10 E/ Z-tetraenoic acid isobutylamides in rats.
Study of metabolism suggests that alkamides of Echinacea are metabolised by cytochrome P450 and may affect the CYP450-mediated metabolism of other concurrently ingested pharmaceuticals. However, effects of E. purpurea root preparations on CYP450 were only shown in vitro.
3.3. Overview of available toxicological data regarding the herbal substance(s)/herbal preparation(s) and constituents thereof
3.3.1. Single dose toxicity
In general, animal studies with different preparation and fractions of Echinacea species have indicated low toxicity (Barrett, 2003).
Acute toxicity of Echinacea purpurea root extract was >3000 mg/kg after p.o. application to NMRI mice. Specifications for the extract are not available (Bauer and Liersch, 1993).
3.3.2. Repeat dose toxicity
No relevant data available.
No relevant data available.
No relevant data available.
3.3.5. Reproductive and developmental toxicity
No relevant data available.
3.3.6. Local tolerance
No relevant data available.
3.3.7. Other special studies
No relevant data available.
In general, the toxicity of E. purpurea is considered to be low. However, the data on toxicity are limited and findings are sometimes difficult to interpret since there is a lack of details regarding the tested preparation or the part of the plant of E. purpurea. Tests on acute and chronic toxicity, reproductive toxicity, genotoxicity and carcinogenicity have not been performed on the dry ethanolic extract covered by the European Union herbal monograph.
3.4. Overall conclusions on non-clinical data
Non-clinical data on purple coneflower root activity supports the traditional use of Echinacea purpurea root dry extracts as traditional herbal medicinal product for the relief of symptoms of common cold.
The traditional use of Echinacea purpurea root dry extracts as traditional herbal medicinal product used for the relief of spots and pimples due to mild acne is not directly supported by relevant non-clinical data.
Specific data on pharmacokinetics and interactions are not available.
Non-clinical information on the safety of purple coneflower root is scarce.
As there is no information on reproductive and developmental toxicity, the use during pregnancy and lactation cannot be recommended.
Based on long experience of use, oral administration of Echinacea purpurea root dry extracts can be regarded as safe at traditionally used doses.
Tests on reproductive toxicity, genotoxicity and carcinogenicity have not been performed, therefore a List Entry is not proposed.
4. Clinical Data
4.1. Clinical pharmacology
4.1.1. Overview of pharmacodynamic data regarding the herbal substance(s)/preparation(s) including data on relevant constituents
Five placebo-controlled randomized studies investigating the immunomodulatory activity of preparations containing extracts of Echinacea in healthy volunteers were reviewed by Melchart et al., (1995). A total of 134 (18 female and 116 male) healthy volunteers between 18 and 40 years of age were studied. Two studies (2 and 3a) tested oral ethanolic extracts of roots of E. purpurea, (study 2: ethanolic extract, corresponding to 333 mg of roots, study 3a: 380 mg of dried extract made with 50% ethanol (V/V)). Test and placebo preparations were applied for four (study 5) or five (studies 1-4) consecutive days. The primary outcome measure for immunomodulatory activity was the relative phagocytic activity of polymorphonuclear neutrophil granulocytes (PNG), measured in studies 1 and 2 with a microscopic method and in studies 3, 4, and 5 with two different cytometric methods. The secondary outcome measure was the number of leukocytes in peripheral venous blood. Safety was assessed by a screening program of blood and other objective parameters as well as by documentation of all subjective side effects. In studies 1 and 2 the phagocytic activity of PNG was significantly enhanced compared with placebo [maximal stimulation 22.7% (95% confidence interval [CI] 17.5- 27.9%) and 54.0% (8.4-99.6%), respectively], while in the other studies no significant effects were observed. Analysis of intragroup differences revealed significant changes in phagocytic activity during the observation periods in five test and three control groups. Leukocyte number was not influenced significantly in any study. Side effects due to the test preparations could not be detected. The study showed immunomodulatory activity of the E. purpurea radix extract tested in study 2. The negative results of the other 3 studies are difficult to interpret due to the different methods for measuring phagocytosis, the relevant changes in phagocytic activity within most placebo and treatment groups during the observation period, and the small sample sizes. Further studies should be performed on patients rather than healthy volunteers and use standardized or chemically defined monopreparations of Echinacea (Melchart et al., 1995).
In a double-blind study, 24 healthy male volunteers took three times 30 drops of an ethanolic extract of purple coneflower root (detailed specifications of the extract are not given) or placebo daily for
5 days. By day 5 a significant increase in phagocytosis of 120% was observed in the verum group, compared to 20% in the placebo group. The effect was transient and phagocytotic activity returned to normal within 6 days (Jurcic et al., 1989).
The effect of Echinacea tablets containing 675 mg of E. purpurea root extract and 600 mg ofEchinacea angustifolia root extract, prepared by ethanol extraction (the concentration of ethanol is not declared in the article) on the expression of leucocyte heat shock protein 70 (hsp70), erythrocyte haemolysis, plasma antioxidant status, serum chemistry, haematological values and plasma alkylamide
concentrations. Eleven healthy individuals (26–61 years of age) were evaluated at baseline (day 1) and on day 15 after consuming two commercially blended Echinacea tablets daily for 14 days. Echinacea supplementation enhanced the fold increase in leucocyte hsp70 expression after a mild heat shock
(P = 0.029). White cell counts (WCC) were also increased (P = 0.043). A preventative effect against free radical induced erythrocyte haemolysis (P = 0.006) indicative of an antioxidant effect was also observed. The authors suggest that Echinacea may invoke an immune response through altered expression of hsp70 and increased WCC (Agnew et al., 2005).
Echinacea extract or placebo was administered to volunteers at the onset of their cold for a period of 7 days, with 8 doses (5 ml/dose) on day 1 and 3 doses on subsequent days. Extract was prepared by extraction of herb and root of Echinacea purpurea by water and ethanol (concentration not reported in the article), followed by purification of alkamides, cichoric acind and polysaccharides to >95 % puritiy and their dissolution in 40 % ethanol to a final concentration of 0.25, 2.5 and 25.5 mg/ml respectively. Fasting blood samples were obtained before and during their colds. The decrease in total daily symptomatic score was more evident in the Echinacea group than in the placebo group. These effects of Echinacea were associated with a significant and sustained increase in the number of circulating total white blood cells, monocytes, neutrophils and NK cells. In the later part of the cold, the Echinacea treatment suppressed the cold-related increase in superoxide production by the neutrophils. The authors suggested that this extract, by enhancing the non-specific immune response and eliciting free radical scavenging properties, may have led to a faster resolution of the cold symptoms (Goel et al., 2005).
Table 5: Overview of pharmacodynamic data
Assessment report on Echinacea purpurea (L.) Moench, radix
Assessor’s overall conclusions on pharmacodynamics
Increased phagocytosis was observed in two studies on purple coneflower root extract as a single ingredient, while detailed composition of extracts is not available. In studies where a combination herbal product was investigated it is difficult to interpret which plant or part of E. purpurea was responsible for the effect (leucocyte hsp70 expression, increased WCC, preventative effect against free radical induced erythrocyte haemolysis, antioxidant effect, suppressed cold-related increase in superoxide production by the neutrophils).
4.1.2. Overview of pharmacokinetic data regarding the herbal substance(s)/preparation(s) including data on relevant constituents
Serial plasma samples from 9 healthy volunteers who ingested 4 Echinacea tablets, each containing extract equivalent to 675 mg of E. purpurea root plus 600 mg of E. angustifolia root prepared from the dried ethanolic extracts (concentratin of ethanol is not given in the article), immediately after a standard high fat breakfast were examined. Caffeic acid conjugates could not be identified in any plasma sample at any time after tablet ingestion. Alkamides were rapidly absorbed and were measurable in plasma 20 min after tablet ingestion and remained detectable for up to 12 h. Concentration-time curves for 2,4-diene and 2-ene alkamides were determined. The maximum concentrations for the sum of alkamides in human plasma were reached within 2.3 hours post ingestion and averaged 336±31 ng eq/ml plasma. No obvious differences were observed in the pharmacokinetics of individual or total alkamides in 2 additional fasted subjects who took the same dose of the Echinacea preparation (Matthias et al., 2005b).
The relative oral bioavailability of alkylamides from two different Echinacea dosage forms (liquid and tablet) were compared in a small two-way crossover study in humans (n = 3). The liquid preparation investigated contained a mixture of E. purpurea root (300 mg/ml) and E. angustifolia root (200 mg/ml) extracted in 60% ethanol. The tablet preparation investigated was also a mixture of E. purpurea root (675 mg/tablet) and E. angustifolia root (600 mg/tablet), but was prepared from the dried 60% ethanolic extracts of these two Echinacea species. Alkylamides were found to be rapidly absorbed and measurable in plasma from both preparations. No significant differences in the tetraene alkylamide pharmacokinetic parameters for T1/2, AUCt-lin and Cmax in the two different preparations were found.
Tmax increased from 20 min for the liquid to 30 min for the tablet, which is not unexpected as the tablet required time for disintegration before absorption could occur. These results suggested that there was no significant difference in the bioavailability of alkylamides from the liquid and tablet Echinacea formulations. Furthermore, the results also indicated that the absorption site and any alkylamide loss due to digestive processes were similar in both preparations (Matthias et al., 2007).
The study made by Moltó et al. (2011) investigated the potential of E. purpurea to interact with the boosted protease inhibitor darunavir-ritonavir. Fifteen HIV-infected patients receiving antiretroviral therapy including darunavir-ritonavir (600/100 mg twice daily) for at least 4 weeks were included.
E. purpurea root extract capsules were added to the antiretroviral treatment (500 mg every 6 h) from days 1 to 14. Darunavir concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, and 12 h after a morning dose of darunavir- ritonavir on days 0 (darunavir-ritonavir) and 14 (darunavir-ritonavir plus echinacea). Individual darunavir pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14. The median age was 49 (range, 43 to 67) years, and the body mass index was 24.2 (range, 18.7 to 27.5) kg/m(2). Echinacea was well tolerated, and all participants completed the study. The geometric mean ratio for darunavir coadministered with echinacea relative to that for
darunavir alone was 0.84 (90% CI, 0.63-1.12) for the concentration at the end of the dosing interval, 0.90 (90% CI, 0.74-1.10) for the area under the concentration-time curve from 0 to 12 h, and 0.98 (90% CI, 0.82-1.16) for the maximum concentration. In summary, coadministration of E. purpurea with darunavir-ritonavir was safe and well tolerated. Individual patients did show a decrease in darunavir concentrations, although this did not affect the overall darunavir or ritonavir pharmacokinetics. Although no dose adjustment is required, monitoring darunavir concentrations on an individual basis may give reassurance in this setting.
The aim of an open-label, fixed-sequence study made by Moltó et al. (2012) was to investigate the potential E. purpurea to interact with etravirine, a nonnucleoside reverse transcriptase inhibitor of HIV. Fifteen HIV-infected patients receiving antiretroviral therapy with etravirine (400 mg once daily) for at least 4 weeks were included. E. purpurea root/extract-containing capsules were added to the antiretroviral treatment (500 mg every 8 h) for 14 days. Etravirine concentrations in plasma were determined by HPLC immediately before and 1, 2, 4, 6, 8, 10, 12, and 24 h after a morning dose of etravirine on day 0 and etravirine plus E. purpurea on day 14. Individual etravirine pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14. The median age was 46 years (interquartile range, 41 to 50), and the median body weight was 76 kg (interquartile range, 68 to 92). Echinacea was well tolerated, and all participants completed the study. The geometric mean ratio for etravirine coadministered with E. purpurea relative to etravirine alone was 1.07 (90% CI, 0.81 to 1.42) for the maximum concentration, 1.04 (90% CI, 0.79 to 1.38) for the area under the concentration-time curve from 0 to 24 h, and 1.04 (90% CI, 0.74 to 1.44) for the concentration at the end of the dosing interval. The coadministration of E. purpurea with etravirine was safe and well tolerated in HIV-infected patients; the data suggest that no dose adjustment for etravirine is necessary.
Table 6: Overview of pharmacokinetic data
Assessor’s overall conclusions on pharmacokinetics
Evidence were provided that alkamides are orally available from liquid extracts and tablets and that their pharmacokinetics is in agreement with the daily regimen already recommended for Echinaceae purpureae radices extracts and there was no significant difference in the bioavailability of alkylamides from the liquid and tablet Echinacea formulations. In contrast, caffeic acid conjugates could not be identified in any plasma sample; therefore their oral bioavailability is questionable.
In vivo, coadministration of E. purpurea with the protease inhibitor darunavir-ritonavir and the nonnucleoside reverse transcriptase inhibitor etravirine was safe and well-tolerated. Further pharmacokinetic testing is necessary to evaluate possible pharmacokinetic interactions of E. purpurea root preparations.
4.2. Clinical efficacy
Several reviews on studies of the effects of Echinacea purpurea herbal products (aerial parts, roots and combinations) in clinical trials have been published (Barnes et al., 2005; Barnes et al., 2007; Barrett, 2003; Bradley, 2006; ESCOP, 2003 and 2009; PDR, 2007; Blumenthal et al., 2000; Bauer and Liersch, 1993; Karsch-Völk et al., 2014, Linde et al., 2006; Melchart et al., 1994; Melchart et al., 2004; Schoop et al., 2006; Shah et al., 2007). They all review the same studies, which are listed also in this AR and in the AR of E. purpurea herba.
4.2.1. Dose response studies
In a double-blind, placebo-controlled study, 180 patients (18-60 years old) with influenza, randomized into three groups of 60, were given a tincture of purple coneflower root made with 55% ethanol (V/V) at daily dosages corresponding to 450 mg or 900 mg of dried root, or placebo. After 3-4 days and 8-10 days, there was no statistical difference in symptoms between the group taking the 450 mg dose and the placebo group. In contrast, the group taking the 900 mg dose showed a highly significant reduction in symptom score at both time points (p < 0.0001). An effect from the higher dose was seen after 3 to 4 days, but the full effect was not seen for 8-10 days (Bräunig et al., 1992). This trial is frequently referred to as a plausible evidence of the efficacy of preparations of E. purpurea root, for the treatment of symptoms associated with common cold (Blumenthal et al., 2000; Melchart et al., 1994; Barrett et al., 1999).
Table 7: Dose- response clinical studies on humans
4.2.2. Clinical studies (case studies and clinical trials)
Echinacea purpurea radix as a single ingredient
289 volunteers from four military establishments and one industrial plant participated in a double- blind, placebo-controlled study to investigate the efficacy of Echinacea extracts in the prevention of upper respiratory tract infections. Randomised groups were instructed to take twice daily for 12 weeks 50 drops (ca. 1 ml) of one of three trial preparations: ethanolic extract (1:11, ethanol 30%) of purple coneflower root (Group A, n = 99) or E. angustifolia root (Group B, n = 100), or an ethanolic placebo solution (Group C, n = 99). 244 participants fully conformed with the protocol: 85, 84 and 75 in Groups A, B and C, respectively. The average time until occurrence of first upper respiratory tract infections was 69, 66 and 65 days, and 29%, 32% and 37% of participants had at least one upper respiratory tract infection, in Groups A, B and C, respectively. Although these results show a trend of relative reduction in risk of infection of 20% for purple coneflower root compared to placebo, the results were not statistically significant (Melchart et al., 1998).
Echinacea purpurea radix in combination with other herbal drugs
In a randomized, double-blind, placebo-controlled study the efficacy and safety of different doses and preparations of Echinacea purpurea in the treatment of common cold. 246 of 559 recruited healthy, adult volunteers caught a common cold and took 3 times daily 2 tablets of either 6.78 mg of Echinacea purpurea dry extract from 95% herba and 5% radix, (extraction solvent not reported in this article), Echinacea purpurea concentrate (same preparation at 7 times higher concentration), special Echinacea purpurea radix preparation (dry extract from root of Echinacea purpurea, 29.6 mg per tablet, extraction solvent not reported in this article) or placebo until they felt healthy again but not longer than 7 days. The primary endpoint was the relative reduction of the complaint index defined by 12 symptoms during common cold according to the doctor’s record. Echinacea purpurea dry extract from 95% herba and 5% radix and its concentrated preparation were significantly more effective than the special Echinacea extract or placebo. All treatments were well tolerated. Among the Echinacea groups the frequency of adverse events was not significantly higher than in the placebo group. Therefore, Echinacea concentrate as well as Echinacea purpurea dry extract from 95% herba and 5% radix represent a low-risk and effective alternative to the standard symptomatic medicines in the acute treatment of common cold (Brinkeborn et al., 1999).
A double-blind randomized placebo-controlled trial was performed on 263 patients to evaluate the use of commercially available fixed combination herbal remedy containing ethanolic-aqueous extracts of
Herba thujae occidentalis, Radix echinaceae (purpureae + pallidae = 1 + 1) and Radix baptisiae, 2, 7.5 and 10 mg per tablet, respectively. The aim of the study was to verify clinical efficacy shown in recent studies under (i) good clinical practice (GCP) quality assurance and (ii) common situations at family doctors. Patients attending one of 15 study centres (practitioners) as a result of an acute common cold were randomised to the double-blind placebo-controlled study. Three tablets of study medication were applied t.i.d. for 7 to 9 days. Patients daily documented the intensity of 18 cold symptoms, as well as the cold overall, using a 10-point scale and estimated their general well-being using the Welzel-Kohnen colour scales. Additionally, the severity of illness was assessed by the physician on days 4 and 8 (CGI- 1). The main and confirmatory outcome measure was expressed as a total efficacy value. This was gauged from the z-standardised AUC values of the primary endpoints (rhinitis score, bronchitis score, CGI-1 and general well-being). Adverse events, overall tolerability, vital signs and laboratory parameters were documented. For safety analysis, all patients were used. 259 patients were evaluable for primary efficacy analysis (ITT). Results were confirmed analysing only the 238 valid cases (VCs). The primary efficacy parameters showed the superiority of the herbal remedy over placebo (p < 0.05). Effect size was 20.6% of the standard deviation (90% CI: 0.04-41.1%; ITT) and 23.1% (1.7-44.5%;
VC). In relation to the general well-being, the effect size was 33.9% of the standard deviation (12.5- 55.3%; VC). Patients who suffered from at least moderate symptom intensity at baseline showed response rates (at least 50% improvement of the global score, day 5) of 55.3% in the herbal remedy group and 27.3% in the placebo group (p = 0.017; NNT = 3.5). In the subgroup of patients who started therapy at an early phase of their cold, the efficacy of the herbal remedy was most prominent (p = 0.014 for the primary efficacy parameter). The therapeutic benefit of the herbal remedy had already occurred on day 2 and reached significance (p < 0.05) on day 4, and continued until the end of the treatment in the total score of symptoms, bronchitis score and rhinitis score, as well as in the patients’ overall rating of the cold intensity. At that time, equal levels of improvement were reached three days earlier in the verum group than in the placebo group. In 26 patients receiving the herbal remedy and 23 patients receiving placebo, adverse events were reported. Adverse drug reactions were suspected in 2 patients in the verum group and in 4 patients in the placebo group. Serious adverse events did not occur. This study shows that the herbal remedy is effective and safe. The therapeutic benefit consists of a rapid onset of improvement of cold symptoms. If patients with colds are able to start the application of the herbal remedy as soon as practical after the occurrence of the initial symptoms, the benefit would be expected to increase (Henneicke-von Zepelin et al., 1999).
The aim of another study was to determine the efficacy of an Echinacea compound herbal tea preparation comprising E. purpurea herb and extract of E. purpurea root equivalent to 1275 mg dried herb and root per tea bag, (futher details about the product are not reported in the article) given at early onset of cold or flu symptoms in a random assignment double-blind placebo-controlled study. A total of 95 subjects with early symptoms of cold or flu (runny nose, scratchy throat, fever) were randomly assigned to receive Echinacea compound herbal tea 5 to 6 cups per day titrating to 1 over 5 days or placebo in a double-blind situation. Each participant completed a questionnaire 14 days after beginning the program. The efficacy, number of days the symptoms lasted and number of days for change were measured with a self scoring questionnaire. The study period was 90 days (1 January 1999 to 30 March 1999). There was a significant difference between the experimental group (Echinacea compound herbal tea preparation) and control group (placebo) for all 3 questions measured: p < 0.001. There were no negative effects reported by any of the subjects in either group. Treatment with Echinacea compound herbal tea at early onset of cold or flu symptoms was effective for relieving these symptoms in a shorter period of time than a placebo (Lindenmuth and Lindenmuth, 2000).
The efficacy of dried, encapsulated, whole-plant Echinacea as early treatment for the common cold in a randomised, double-blind, placebo-controlled community-based trial was assessed, on 148 students with common colds of recent onset was assessed. Each active capsule contained a dried mixture of E. angustifolia root (50% [123 mg]), E. purpurea root (25% [62 mg]), and E. purpurea herb (25% [62 mg]). Echinacea capsules also contained thyme (49 mg) and peppermint (31 mg) to disguise taste and flavour, as well as citric acid (3 mg) as a preservative. The placebo capsules contained 333 mg of alfalfa. The patients took 4 capsules 6 times during the first 24 hours of the study, and 4 capsules 3 times each day thereafter until symptoms resolved, for a maximum of 10 days. Severity and duration of self-reported symptoms of upper respiratory tract infection were recorded. No statistically significant differences were detected between the Echinacea and placebo groups for any of the measured outcomes. Trajectories of severity over time were nearly identical in the 2 groups. Mean cold duration was 6.01 days in both groups as a whole, 5.75 days in the placebo group, and 6.27 days in the Echinacea group (between-group difference, -0.52 day [95% CI, -1.09 to 0.22 days]). After controlling for severity and duration of symptoms before study entry, sex, date of enrolment, and use of nonprotocol medications, researchers found no statistically significant treatment effect (adjusted hazard ratio, 1.24 [CI, 0.86 to 1.78]). Multivariable regression models assessing severity scores over
time failed to detect statistically significant differences between the Echinacea and placebo groups (Barrett et al., 2002).
A formulation containing alkamides, cichoric acid, and polysaccharides at concentrations of 0.25, 2.5, and 25 mg/ml, respectively, was prepared from freshly harvested Echinacea purpurea herb and root. The objective of this study was to test the efficacy of this highly standardized formulation in reducing the severity and duration of symptoms of a naturally acquired common cold. In a randomized, double- blind, placebo-controlled trial, 282 subjects aged 18-65 years with a history of two or more colds in the previous year, but otherwise in good health, were recruited. The subjects were randomized to receive either Echinacea or placebo. They were instructed to start the Echinacea or placebo at the onset of the first symptoms related to a cold, consuming 10 doses the first day and 4 doses per day on subsequent days for 7 days. Severity of symptoms (10-point scale: 0, minimum; 9, maximum) and dosing were recorded daily. A nurse examined the subjects on the mornings of days 3 and 8 of their cold. A total of 128 subjects contracted a common cold (59 Echinacea, 69 placebo). The total daily symptom scores were found to be 23.1% lower in the Echinacea group than in placebo in those who followed all elements of the study protocol (P < 0.01). Throughout the treatment period, the response rate to treatments was greater in the Echinacea group. A few adverse event profiles were observed in both groups. Early intervention with a standardized formulation of Echinacea resulted in reduced symptom severity in subjects with naturally acquired upper respiratory tract infection. Further studies with larger patient populations appear to be warranted (Goel et al., 2004).
Barrett et al. (2010) designed a randomized, controlled trial with the aim to assess the potential benefits of Echinacea as a treatment of common cold. There were 719 patients included, aged 12 to 80 years, with new-onset common cold. Patients were assigned to 1 of 4 parallel groups: no pills, placebo pills (blinded), Echinacea pills (blinded), or Echinacea pills (unblinded, open-label). Echinacea groups received the equivalent of 10.2 g of dried Echinacea root during the first 24 hours and 5.1 g during each of the next 4 days. Indistinguishable placebo tablets contained only inert ingredients.. Echinacea tablets contained the equivalent of 675 mg of E. purpurea root and 600 mg of E. angustifolia root, each standardized to 2.1 mg of alkamides. The primary outcome was the area under the curve for global severity, with severity assessed twice daily by self-report using the Wisconsin Upper Respiratory Symptom Survey, short version. Secondary outcomes included interleukin-8 levels and neutrophil counts from nasal wash, assessed at intake and 2 days later. Of the 719 patients enrolled, 713 completed the protocol. Mean age was 33.7 years, 64% were female, and 88% were white. Mean global severity was 236 and 258 for the blinded and unblinded Echinacea groups, respectively; 264 for the blinded placebo group; and 286 for the no-pill group. A comparison of the 2 blinded groups showed a 28-point trend (95% CI, -69 to 13 points) toward benefit for Echinacea (P = 0.089). Mean illness duration in the blinded and unblinded Echinacea groups was 6.34 and 6.76 days, respectively, compared with 6.87 days in the blinded placebo group and 7.03 days in the no-pill group. A comparison of the blinded groups showed a nonsignificant 0.53-day (CI, -1.25 to 0.19 days) benefit (P = 0.075). Median change in interleukin-8 levels and neutrophil counts were also not statistically significant (30 ng/L and 1 cell/high-power field [hpf] in the no-pill group, 39 ng/L and 1 cell/hpf in the blinded placebo group, 58 ng/L and 2 cells/hpf in the blinded Echinacea group, and 70 ng/L and 1 cell/hpf in the open-label Echinacea group). Higher-than-expected variability limited power to detect small benefits. Illness duration and severity were not statistically significant with Echinacea compared with placebo. These results do not support the ability of this dose of the Echinacea formulation to substantively change the course of the common cold.
Jawad et al. (2012) investigated the safety and efficacy of E. purpurea extract in the prevention of common cold episodes in a large population over a 4-month period creating a randomized, double- blind and placebo-controlled study. Therefore, 755 healthy subjects were allocated to receive either placebo or an alcohol extract from freshly harvested E. purpurea. Extract was prepared by alcoholic
(57.3% m/m) extraction from freshly harvested E. purpurea with a combination of 95% herba
(DER = 1:12) and 5% roots (DER = 1:11). The sample was microbiologically tested and proven to be free of endotoxins. The batch used in this study (027643) was standardized to contain 5 mg/100 g of dodecatetraenoic acid isobutylamide, based on high performance liquid chromatography measurements. Participants were required to record adverse events and to rate cold-related issues in a diary throughout the investigation period. Nasal secretions were sampled at acute colds and screened for viruses. A total of 293 adverse events occurred with Echinacea and 306 with placebo treatment. Nine and 10% of participants experienced adverse events, which were at least possibly related to the study drug (adverse drug reactions). Thus, the safety of Echinacea was noninferior to placebo. Echinacea reduced the total number of cold episodes, cumulated episode days within the group, and pain-killer medicated episodes. Echinacea inhibited virally confirmed colds and especially prevented enveloped virus infections (P < 0.05). Echinacea showed maximal effects on recurrent infections, and preventive effects increased with therapy compliance and adherence to the protocol. Compliant prophylactic intake of E. purpurea over a 4-month period appeared to provide a positive risk to benefit ratio.
Tiralongo et al. (2012) examined whether a standardised Echinacea formulation (tablets containing 112.5 mg E. purpurea 6:1 root extract and 150 mg E. angustifolia 4:1 root extract, extraction solvent is not reported in the article) is effective in the prevention of respiratory and other symptoms associated with long-haul flights. Therefore, 175 adults participated in a randomised, double-blind placebo-controlled trial travelling back from Australia to America, Europe, or Africa for a period of 1-5 weeks on commercial flights via economy class. Participants took Echinacea (root extract, standardised to 4.4 mg alkylamides) or placebo tablets. Participants were surveyed before, immediately after travel, and at 4 weeks after travel regarding upper respiratory symptoms and travel-related quality of life. Respiratory symptoms for both groups increased significantly during travel (P<0.0005). However, the Echinacea group had borderline significantly lower respiratory symptom scores compared to placebo (P = 0.05) during travel. Supplementation with standardised Echinacea tablets, if taken before and during travel, may have preventive effects against the development of respiratory symptoms during travel involving long-haul flights.
The study by Barth et al. (2015) was performed with an oral solution (KJ) containing a fixed combination of aqueous ethanolic extracts of Justicia adhatoda L. leaf, E. purpurea root, and Eleutherococcus senticosus (Rupr. & Maxim.) Harms root. The KJ solution contained 9 mg/ml genuine extract (in 55% ethanol) from 23–63 mg dried root of Echinacea purpurea radix, 14 mg/ml genuine extract (in water) from 49–70 mg dried leaves of Justicia adhatoda folium and 2mg/ml genuine extract (in 70 % ethanol) from 34–60 mg dried root of Eleutherococcus senticosus radix. The solution base comprised sorbitol, aroma, ginger extract, peppermint oil, dark syrup, benzoate and water. The preparation was standardized on contents of vasicine (0.2mg/ml), chicoricacid (0.8mg/ml), and eleutherosides B and E (0.03 mg/ml). It is approved in Scandinavia as an herbal medicinal product for respiratory tract infection treatment. The clinical trial aimed to compare the antitussive effect of KJ with placebo (PL) and bromhexine (BH) among patients of 18-65 years old with non-complicated upper respiratory infections (URI). The study performed a parallel-group, randomized, double-blinded, placebo-controlled trial in 177 patients with acute URI over a 5 day period. It investigated the antitussive effects of a KJ (30 ml/day; 762 mg genuine extracts with standardized contents of 0.2 mg/ml vasicine, 0.8 mg/ml chicoric acid, and 0.03 mg/ml eleutherosides B and E), bromhexine hydrochloride (24 mg/30 ml/day) and PL on cough and blood markers. The primary outcome was cough relief, which was assessed as the change of cough frequency from baseline (cough index). Secondary outcomes were safety with regards to reported adverse events (AEs) and hematological data. Both KJ and BH relieved cough more effectively than placebo. On the third and fourth days of treatment, faster improvement in the group receiving KJ compared to in the groups receiving BH
(100%) or PL (100%) was observed, indicating a slightly shorter recovery time in the KJ group. KJ showed a good tolerability and safety profile. KJ exerted significant antitussive effects in URI.
Rauš et al. (2015) performed a randomized, double-blind, double-dummy, multicenter, controlled clinical trial in which they compared Echinacea with the neuraminidase inhibitor oseltamivir. Following informed consent, 473 patients with early influenza symptoms (≤48 hours) were recruited in primary care in the Czech Republic and randomized to either 5 days of oseltamivir followed by 5 days of placebo, or 10 days of an E. purpurea-based hotdrink formulation. The hotdrink contained the ethanolic extract (65% V/V) of freshly harvested E. purpurea. The tinctures from herba (drug extraction ratio, DER 1:12) and from the roots (DER 1:11) are combined at a ratio of 95% to 5%. 240 mg of above active ingredient was concentrated to extractum spissum, which was supplemented with 276.5 mg of Sambucus fructus succus recentis (elderberry) and excipients were added sufficient to give 1 ml ofhotdrink. The proportion of recovered patients (influenza symptoms rated as absent or mild in the evening) was analyzed for noninferiority between treatment groups using a generalized Wilcoxon test with significance level α = 0.05 (2-sided) and using a CI approach in the per-protocol sample. Recovery from illness was comparable in both treatment groups at 1.5% versus 4.1% after
1 day, 50.2% versus 48.8% after 5 days, and 90.1% versus 84.8% after 10 days of treatment with E. purpurea-based hotdrink formulation and oseltamivir, respectively. Noninferiority was demonstrated for each day and overall (95% CI, 0.487–0.5265 by generalized Wilcoxon test). Very similar results were obtained in the group with virologically confirmed influenza virus infections and in a retrospective analysis during the peak influenza period. The incidence of complications was lower with E. purpurea– based hotdrink formulation than with oseltamivir (2.46% vs 6.45%; P = 0.076) and fewer adverse events (particularly nausea and vomiting) were observed with E. purpurea-based hotdrink formulation. In this study it was demonstrated that E. purpurea-based hotdrink formulation was as effective as oseltamivir in the early treatment of clinically diagnosed and virologically confirmed influenza virus infections with a reduced risk of complications and adverse events.
Table 8: Clinical studies on humans with Echinaceae purpureae radix and its combinations
4.3. Clinical studies in special populations (e.g. elderly and children)
No data available.
4.4. Overall conclusions on clinical pharmacology and efficacy
Echinacea purpurea root extract was not statisticaly significant superior than placebo in preventing of upper respiratory tract infection in one double-blind, placebo-controlled study (Melchart et al., 1998). In only one double-blind, placebo-controlled study on patients with influenza, a tincture of purple coneflower root (1:5, ethanol 55%) showed significant reduction in symptom score at both time points (after 3-4 and 8-10 days) and the effect was dose-dependent (Bräunig et al., 1992).
In many double-blind, placebo-controlled trials Echinacea purpurea root in combination with other herbal drugs (Echinacea purpurea herb, E. angustifolia root or other plant species) was reported to be efficient in reducing the severity of symptoms of common cold or flu. One placebo-controlled, double- blinded and randomized trial found that Echinacea purpurea root in combination with other herbal drugs could reduce the total number of cold episodes. Another PCR trial attributed benefits in prevention of upper respiratory infections (URI) to a combination including Echinacea purpurea root and one in treatment of an URI. There were no significant differences between placebo and verum group in two double-blind, placebo-controlled trials in reducing the severity of common cold or flu. The results are difficult to interpret, it is difficult to say which component is the active one, and the pharmacological effects are probably achieved by synergistic effect.
The clinical evidence of efficacy is not sufficient for Echinacea purpurea root extract to be considered as well-established medicinal product but it supports plausibility of efficacy of the relief of symptoms of common cold based on the long standing traditional use.
Threre are no clinical evidence on the efficacy of Echinacea purpurea root dry extracts for the relief of spots and pimples due to mild acne.
5. Clinical Safety/Pharmacovigilance
5.1. Overview of toxicological/safety data from clinical trials in humans
A systematic review, based on clinical studies, case reports and surveillance programmes of national medicines regulatory authorities and WHO, concluded that Echinacea products have a good safety profile when taken in the short term, while data on long-term use is not available. If adverse events occur they tend to be transient and reversible, the most common being gastrointestinal or skin related (Huntley et al., 2005).
No adverse events were reported in a clinical study in which 180 patients randomised in 3 groups of 60 patients with influenza received oral treatment daily for 10 days with a tincture of purple coneflower root made with ethanol 55% (V/V), equivalent to 450 mg or 900 mg of dried root; the preparation was well tolerated (Bräunig et al., 1992).
In a clinical study, 10 out 99 subjects who took 2 times 50 drops (2 times 1 ml) of a ethanolic extract of purple coneflower root (detailed specifications of the extract are not given) daily for 12 weeks reported adverse effects, compared to 11 out of 90 subjects in the placebo group; none of the adverse effects were serious or required therapeutic action (Melchart et al., 1998).
Table 9: Clinical safety data from clinical trials
Table 10: Pharmacovigilance reports from Member States (causality has not been evaluated)
5.2. Patient exposure
Data obtained from 2935 patients, tested for safety during clinical trials described above, showed the following results: Only few minor adverse events were reported, e. g. pruritus, diarrhea or headache, and no serious adverse events occurred. Some articles do not specify adverse events reported.
According to these data, preparations of Echinacea purpurea radix in combination with other botanical preparations can be assessed as safe.
Aside from data about the presence of many products containing Echinacea purpurea radix on the market and data from studies, there are no concrete data concerning patient exposure.
5.3. Adverse events, serious adverse events and deaths
In rare cases hypersensitivity reactions e.g. skin reactions may occur (ESCOP 2009, Bauer and Liersch 1993, Blumenthal et al. 2000, Mullins 1998). Individuals with allergic tendencies, particularly those with known allergy to other members of the Asteraceae family should be advised to avoid Echinacea (Barnes et al., 2007, Bauer and Liersch, 1993).
In an analysis of the Australian Adverse Drug Reactions Advisory Committtee’s database of events of IgE-mediated hypersensitivity reactions, 51 reports were found to be related to Echinacea use. 26 reactions including urticaria, angio-oedema, asthma and anaphylaxis were confirmed to be IgE- mediated reactions to Echinacea. More than half of the affected patients had a history of asthma, allergic rhinitis or atopic dermatitis. Four persons required hospitalization due to their reactions and no deaths occurred. In 94% of patients, the symptoms appeared within 24 hours of Echinacea ingestion. 80% of the patients included were female and the medium age was 32 years (PDR, 2007, Mullins & Heddle, 2002).
Six major herbal references published from 1996 to 2000 were selected to evaluate the adequacy of their toxicological information in light of published adverse events. To identify herbs most relevant to toxicology, herbal-related calls to regional California Poison Control System, San Francisco division (CPCS-SF) in 1998 were reviewed and 12 herbs were identified (defined as botanical dietary supplements) most frequently involved in these CPCS-SF referrals. Medline was searched (1966 to 2000) to identify published reports of adverse effects potentially related to these same 12 herbs. Each herbal reference text was scored on the basis of information inclusiveness for the target 12 herbs, with a maximal overall score of 3. The herbs, identified on the basis of CPCS-SF call frequency were: St John’s wort, ma huang (Ephedra spp.), echinacea, guarana, ginkgo, ginseng, valerian, tea tree oil, goldenseal (Hydrastis canadensis), arnica, yohimbe (Pausinystalia johimbe) and kava kava (Piper methysticum). The overall herbal reference scores ranged from 2.2 to 0.4 (median 1.1). The Natural Medicines Comprehensive Database received the highest overall score and was the most complete and useful reference source. All of the references, however, lacked sufficient information on management of herbal medicine overdose, and several had incorrect overdose management guidelines that could negatively impact patient care. The authors concluded that current herbal reference texts do not contain sufficient information for the assessment and management of adverse health effects of botanical therapies (Haller et al., 2002).
Reports to poison control centers (PCCs) were characterised involving two widely used herbal dietary supplements (HDSs), Echinacea, and St. John’s wort (SJW). METHODS: Data were purchased from the American Association of Poison Control Center’s (AAPCC) toxic exposure surveillance system (TESS(R)) on reports made to PCCs in 2001 involving Echinacea or SJW. Analyses were limited to those cases in which Echinacea or SJW were the only associated products, and in which these HDSs were deemed primary to observed adverse effects. Descriptive statistics were generated for selected demographic
and exposure-related variables. During 2001, PCCs were contacted regarding 406 exposures involving Echinacea and 356 exposures involving SJW. Most of the reported exposures for both HDSs occurred among children 5 years and younger, and the majority of exposures were coded as unintentional. For both HDSs, exposures among patients >/=20 years old were more likely to be associated with adverse effects. Intentional exposures accounted for 21% of SJW cases and 3% of Echinacea cases, with 13% of SJW exposures reported as ‘suspected suicidal’. TESS represents a potentially important means of assessing and characterizing HDS-related adverse effects. It was concluded that detailed studies validating the clinical events and outcomes of a sample of exposures reported to TESS(R) might offer substantial insights into adverse events that could be systematically studied with other, established pharmacoepidemiological study designs (Gryzlak et al., 2007).
Goel et al. (2004) mention that there were “a few adverse event profiles” observed in both groups of their trials, but they are not further specified in their article.
In the clinical trial by Jawad et al. (2012), 755 healthy subjects received either an ethanolic extract from freshly harvested E. purpurea or placebo and were requested to report adverse events. Echinacea preparation was prepared by ethanolic (57.3% m/m) extraction from freshly harvested E. purpurea with a combination of 95% herba (DER = 1:12) and 5% roots (DER = 1:11). The sample was microbiologically tested and proven to be free of endotoxins. The batch used in this study (027643) was standardized to contain 5 mg/100 g of dodecatetraenoic acid isobutylamide, based on highperformance liquid chromatography measurements. A total of 293 adverse events occurred with Echinacea and 306 with placebo treatment. Nine and 10% of participants experienced adverse events, which were at least possibly related to the study drug. In the article it is not announced which kind of adverse events appeared.
The clinical trial by Rauš et al. (2015) mentions particularly nausea and vomiting as adverse events. The Echinacea preparation was associated with a reduced risk of complications and adverse events compared to oseltamivir.
Barth et al. (2015) tested an oral solution combination containing E. purpurea radix. Two out of 66 patients in the Echinacea group reported minor adverse events (pruritus, diarrhea, abdominal pain, skin rash), but proportion of patients reporting adverse events did not significantly differ between groups. Although it is not specified which minor adverse events were observed in the Echinacea group, the oral solution was assessed as well-tolerated.
Serious adverse events and deaths: None reported.
5.4. Laboratory findings
Barth et al. (2015) examined hematologic parameters between verum (Echinacea purpurea radix in combination) and placebo group, but did not found any statistically significant differences.
5.5. Safety in special populations and situations
5.5.1. Use in children and adolescents
There are no sufficient data on safety of purple coneflower root preparations in children; therefore the use of Echinacea purpurea root and preparations thereof is not recommended. This appears as a warning in the monograph and not as a contraindication in accordance with the ‘Guideline on the Summary of Product Characteristics’ dated September 2009.
Godwin et al. (2013) determined how common it is for parents to give natural health products (NHPs) to their children, A total of 53.4% of the 378 eligible parents who were contacted completed the
survey. This represented 333 children. Mean (SD) age of the children was 5.1 (3.3) years. Overall, 28.7% of parents reported using nonvitamin NHPs for their children: teas (primarily chamomile and green teas), Echinacea, fish or omega-3 oils, and a large category of “other” products. These NHPs were most commonly used to improve general health, improve immunity, and prevent colds and infections. Approximately half of the parents (51.7%) believed their children had benefited from taking NHPs, and 4.4% believed their children had experienced adverse side effects.
In case of hypersensitivity to the active substance or to other plants of the Asteraceae (Compositae) family the use is contraindicated. No other concerns requiring a contraindication were identified.
5.5.3. Special warnings and precautions for use
Based on the assumption that Echinacea purpurea radix has immunomodulatory effects, some authors declared, that its use is contraindicated in progressive systemic diseases such as tuberculosis, diseases of the white blood cells system, collagenoses, multiple sclerosis, AIDS, HIV infections, and other immune diseases (Barnes et al., 2005; Barnes et al., 2007; ESCOP 2003 and 2009; Bauer and Liersch, 1993; Blumenthal et al., 2000). None of them, however, had made a thorough assessment on this issue.
At present there is a lack of reliable clinical evidence to support the immunomodulatory effects of Echinacea, but in the view of the seriousness of the conditions listed above it is appropriate to avoid use in these disorders until further information is available (Barnes et al., 2005; Barnes et al., 2007).
In accordance with the ‘Guideline on the Summary of Product Characteristics’ dated September 2009, the statement that Echinacea purpurea radix is not recommended in progressive systemic disorders, autoimmune diseases, immunodeficiencies, immunosupression and diseases of the white blood cell system appears in the section ‘Warnings and precautions for use’ of the monograph on Echinaceae purpureae radix (not as a contraindication).
There is a possible risk of allergic reactions in sensitive individuals. Those patients should consult their doctor before using Echinacea.
Atopic patients and those with asthma should be cautious since rare allergic reactions have been reported (Barnes et al., 2005; Barnes et al., 2007; Huntley et al. 2005). None of these references presented any details on these patients with allergic reactions. There is a possible risk of anaphylactic reactions in atopic patients. Atopic patients should consult their doctor before using Echinacea.
5.5.4. Drug interactions and other forms of interaction
The effect of Echinacea (Echinacea purpurea root) on CYP activity in vivo was assessed by use of the CYP probe drugs caffeine (CYP1A2), tolbutamide (CYP2C9), dextromethorphan (CYP2D6), and midazolam (hepatic and intestinal CYP3A). Twelve healthy subjects (6 men) completed this 2-period, open-label, fixed-schedule study. Caffeine, tolbutamide, dextromethorphan, and oral and intravenous midazolam were administered before and after a short course of Echinacea (400 mg 4 times a day for 8 days) to determine in vivo CYP activities. Echinacea administration significantly increased the systemic clearance of midazolam by 34%, from 32 +/- 7 L/h to 43 +/- 16 L/h (P =0.003; 90% CI, 116%-150%), and significantly reduced the midazolam area under the concentration-time curve by 23%, from 127 +/- 36 microg. h/L to 102 +/- 43 microg. h/L (P =0.024; 90% CI, 63%-88%). In contrast, the oral clearance of midazolam was not significantly altered (P =0.655; 90% CI, 75%- 124%), 137 +/- 19 L/h compared with 146 +/- 71 L/h. The oral availability of midazolam after
Echinacea dosing was significantly increased (P =0.028; 90% CI, 108%-153%), from 0.23 +/- 0.06 to 0.33 +/- 0.13. Hepatic availability (0.72 +/- 0.08 versus 0.61 +/- 0.16; P =0.006; 90% CI, 73%- 90%) and intestinal availability (0.33 +/- 0.11 versus 0.61 +/- 0.38; P =0.015; 90% CI, 125%-203%) were significantly altered in opposite directions. Echinacea dosing significantly reduced the oral clearance of caffeine, from 6.6 +/- 3.8 L/h to 4.9 +/- 2.3 L/h (P =0.049; 90% CI, 58%-96%). The oral clearance of tolbutamide was reduced by 11%, from 0.81 +/- 0.18 L/h to 0.72 +/- 0.19 L/h, but this change was not considered to be clinically relevant because the 90% CIs were within the 80% to 125% range. The oral clearance of dextromethorphan in 11 CYP2D6 extensive metabolizers was not affected by Echinacea dosing (1289 +/- 414 L/h compared with 1281 +/- 483 L/h; P =0.732; 90% CI, 89%- 108%). Echinacea (E. purpurea root) reduced the oral clearance of substrates of CYP1A2 but not the oral clearance of substrates of CYP2C9 and CYP2D6. Echinacea selectively modulates the catalytic activity of CYP3A at hepatic and intestinal sites. The type of drug interaction observed between Echinacea and other CYP3A substrates will be dependent on the relative extraction of drugs at hepatic and intestinal sites. The authors recommended that caution should be used when Echinacea is co- administered with drugs dependent on CYP3A or CYP1A2 for their elimination (Gorski et al., 2004).
The review by Freeman and Spelman (2008) assessed the occurrence of drug interactions with one of the top selling botanical remedies, Echinacea including E. angustifolia, E. pallida, and E. purpurea. Only eight papers containing primary data relating to drug interactions were identified. Herbal remedies made from E. purpurea appear to have a low potential to generate cytochrome P450 (CYP450) drug– herb interactions including CYP 450 1A2 (CYP1A2) and CYP 450 3A4 (CYP3A4). Currently there are no verifiable reports of drug–herb interactions with any Echinacea product. The authors concluded that given the findings, the estimated risk of taking Echinacea products (1 in 100 000), the number of Echinacea doses consumed yearly (> 10 million), the number of adverse events (< 100) and that the majority of use is short term, E. purpurea products (roots and/or aerial parts) do not appear to be a risk to consumers (Freeman and Spelman, 2008).
A report on possible drug-herbal interaction between Echinacea (details of drug administration not stated) and etoposide was published in 2012 (Bossaer & Odle, 2012). A 61-year-old man newly diagnosed with nonsmall cell lung cancer began concurrent chemoradiation with cisplatin and etoposide. He was admitted to the hospital on day 8 of his first cycle and found to be thrombocytopenic. His platelet count eventually reached a nadir of 16 × 10(3)/l, requiring platelet transfusion support. Upon admission, it was discovered that he was taking vitamin B12, vitamin E, vitamin D, vitamin C, Echinacea and ‘vitamin B17’ (laetrile-apricots kernel), which were discontinued. He received his next cycle of chemotherapy without taking herbal products and vitamins and with the addition of pegfilgrastim. His platelet count decreased to a nadir of 44 × 10(3)/l, but he did not require platelet transfusions. Since the patient stopped taking Echinacea after cycle 1, subsequent therapy during cycle 2 served as a control to test hypothesis that Echinacea (documented in in vitro studies to as a cytochrome P450 3A4 inhibitor) interacted with etoposide. As the patient also stopped taking laetrile and his other vitamins after cycle 1, a potential interaction between laetrile and etoposide or cisplatin cannot be fully excluded. Authors of the report concluded that since the exact preparation of Echinacea and corresponding plant extract constituents, was unknown, the interaction remains equivocal. Cautions should be exercised in patients receiving chemotherapy including CYP3A4 substrates (antracyclines, etoposide, vinca alcaloids, taxanes) while taking Echinacea (Bossaer & Odle, 2012).
Assessor’s comment: In a pharmacological study it was found that Echinacea purpurea radix inhibits intestinal CYP3A4 and induces hepatic CYP3A4 (Gorski et al., 2004). Due to unknown formulation and dosages of Echinacea preparation in this case interaction with etoposide could be considered as a signal for interaction between Echinacea purpurea radix preparations and etoposide and other CYP3A4
substrates in spite of the fact that there are no other verifiable reports of drug–herb interactions with any Echinacea product. Further pharmacokinetic testing is necessary before conclusive statements can be made about Echinacea interaction with other drugs.
5.5.5. Fertility, pregnancy and lactation
A review on safety of Echinacea during pregnancy and lactation was published (Perri et al., 2006). They searched 7 electronic databases and compiled data according to the grade of evidence found. They found good scientific evidence from a prospective cohort study that oral consumption of Echinacea during the first trimester does not increase the risk for major malformations. Low-level evidence based on expert opinion shows that oral consumption of Echinacea in recommended doses is safe for use during pregnancy and lactation. They concluded that Echinacea is non-teratogenic when used during pregnancy. Using Echinacea during lactation is not recommended until further high quality human studies can determine its safety.
The outcome ‘pregnancy’ in women that used Echinacea during pregnancy was studied to evaluate the safety of Echinacea. There is no specification which species of Echinacea was evaluated. Since at least half of all pregnancies are unplanned, many women inadvertently use Echinacea in their first trimester. The study group consisted of 206 women who were prospectively followed up after contacting the Motherisk Program regarding the gestational use of Echinacea, 112 women used the herb in the first trimester. This cohort was disease-matched to women exposed to non-teratogenic agents by maternal age, alcohol, and cigarette use. Rates of major and minor malformations between the groups were compared. There were a total of 195 live births, including 3 sets of twins, 13 spontaneous abortions, and 1 therapeutic abortion in the Echinacea group. Six major malformations were reported, including one chromosomal abnormality, and 4 of these malformations occurred with Echinacea exposure in the first trimester. In the control group, there were 206 women with 198 live births, 7 spontaneous abortions, and 1 therapeutic abortion. Seven major malformations were reported. There were no statistical differences between the study and control groups for any of the endpoints analysed. The authors concluded that gestational use of Echinacea during organogenesis is not associated with an increased risk for major malformations (Gallo et al., 2000). The study has several limitations, particularly the small sample size, meaning that the study would have the statistical power only to detect common malformations, and self-report of exposure, since it is possible that misclassification have occurred. In addition participants used a range of different preparations of Echinacea at different dosage regimens, so the study does not provide adequate evidence for any specific preparation (Barnes et al., 2007).
In a survey among 400 Norwegian women (Nordeng & Haven 2004) 36% used herbal drugs during pregnancy with an average of 1.7 products per woman. Echinacea was used by 23% of pregnant woman and was by far the mostly used herb. No information about the plant species, plant part or type of preparation or duration of intake/trimester is given in the article.
Perri et al. (2006) searched 7 electronic databases and compiled data according to the grade of evidence found. Good scientific evidence from a prospective cohort study was found: oral consumption of Echinacea during the first trimester did not increase the risk for major malformations (study performed by Gallo et al. 2000). Low-level evidence based on expert opinion shows that oral consumption of Echinacea in recommended doses is safe for use during pregnancy and lactation. The authors concluded that Echinacea is non-teratogenic when used during pregnancy. Caution is advised using Echinacea during lactation until further high quality human studies can determine its safety.
Nordeng et al. (2011) investigated the use of herbal drugs by pregnant women in relation to concurrent use of conventional drugs, delivery, and pregnancy outcome. Six hundred women at
Stavanger University Hospital Norway were interviewed using a structured questionnaire within five days after delivery. Medical birth charts were reviewed with respect to pregnancy outcome. 39.7% of the women reported the use of herbal drugs during pregnancy, most commonly ginger, iron-rich herbs, Echinacea (7.5%) and cranberry. No information about the Echinacea species, plant part or type of preparation or duration of intake/trimester is given in the article. Although 86.3% of the women reported to have used conventional drugs during pregnancy there were few potential interactions between herbal drugs and conventional drugs. Except for birth weight, there were no significant differences between users and non-users of herbal drugs in general in any of the pregnancy outcomes investigated. Mean birth weight was higher among the users of herbal drugs during pregnancy (3,663 g vs. 3,508 g). There was a significant association between the use of iron-rich herbs during pregnancy and high birth weight, and use of raspberry leaves and caesarean delivery.
The study of Cuzzolin et al. (2010) explored the use of herbal products among Italian pregnant women and the possible influence of herbal consumption on pregnancy outcome. It was conducted over a 10- month period (2 days a week, from January to October 2009) at the Maternity wards of Padua and Rovereto Hospital. Data were collected through a face-to-face interview on the basis of a prestructured questionnaire including socio-demographic characteristics of the enrolled subjects, specific questions on herbal use, information about pregnancy and newborn. In total, 392 interviews were considered. 109 out of 392 women (27.8%) reported to have been taking one or more herbal products during pregnancy, in the 36.7% of cases throughout all pregnancy. The most frequently herbs were chamomile, liquorice, fennel, aloe, valerian, Echinacea (9.2%), almond oil, propolis, and cranberry. No information about the Echinacea species, plant part or type of preparation or duration of intake/trimester is given in the article. Four out of 109 women (3.7%) reported side-effects: constipation after a tisane containing a mix of herbs, rash and itching after local application of aloe or almond oil. Users were more often affected by pregnancy-related morbidities and their neonates were more frequently small for their gestational age. A higher incidence of threatening miscarriages and preterm labours was observed among regular users of chamomile and liquorice.
Holst et al. (2011) performed a survey at the antenatal clinic at Norfolk and Norwich University Hospital between November 2007 and February 2008 among 578 expectant mothers at least 20-weeks pregnant. 57.8% of them used one or more herbal remedies. The most commonly used herbal preparations during pregnancy were ginger, cranberry, raspberry leaf, chamomile, peppermint and Echinacea. No information about the Echinacea species, plant part or type of preparation is given in the article.
In the absence of sufficient data, the use during pregnancy and lactation is not recommended.
No fertility data are available.
No case of overdose has been reported.
5.5.7. Effects on ability to drive or operate machinery or impairment of mental ability
No data available.
5.5.8. Safety in other special situations
5.6. Overall conclusions on clinical safety
The oral administration of Echinacea purpurea root extracts can be regarded as safe for intended use, taking into account recommended contraindications, warnings and precautions for use.
Hypersensitivity reactions e.g. skin reactions were observed. Even though the frequency is not known individuals with allergic tendencies particularly those with known allergy to other members of the Asteraceae (Compositae) family should avoid Echinacea purpurea preparations. Atopic patients and those with asthma should be cautious since rare allergic reactions have been reported. They should consult their doctor before using Echinacea.
Based on the assumption that Echinacea purpurea has immunomodulatory effects, its use is not recommended in cases of progressive systemic disorders, autoimmune diseases, immunodeficiencies, immunosuppression and diseases of the white blood cell system.
There are no sufficient data on safety of purple coneflower root preparations in children under 12 years of age; therefore the use of Echinacea purpurea root and preparations thereof is not recommended.
Due to unreliable studies the use during pregnancy and lactation is not recommended in accordance with general medical practice.
Herbal remedies made from Echinacea purpurea appear to have a low potential to generate cytochrome P450 (CYP450) drug–herb interactions including CYP 450 1A2 (CYP1A2) and CYP 450 3A4 (CYP3A4). Currently there are no verifiable reports of drug–herb interactions with any Echinacea product.
6. Overall conclusions (benefit-risk assessment)
Well-established use of Echinacea purpurea root preparations for the relief of symptoms of common cold is not possible, due to insufficient clinical data. Well-established use of Echinacea purpurea root preparations is also not possible for the relief of spots and pimples due to mild acne, due to the absence of clinical data.
Traditional use of dry extract of Echinacea purpurea root (5.5-7.5:1), extraction solvent ethanol 45% (V/V) for the relief of symptoms of common cold is possible based on it’s longstanding safe use. Traditional use of dry extract of Echinacea purpurea root (4:1), extraction solvent water for the relief of spots and pimples due to mild acne is possible based on its longstanding safe use.
There are data on pharmacological effects of Echinacea purpurea root preparations on immune system of adults but the pharmacological mechanisms and active compounds still remain mainly unclear. So far the only compounds for which the oral availability has been established are alkamides.
Safety and plausible efficacy in children under 12 years of age has not established, therefore the use in this age group is not recommended.
Toxicological data are limited. However a certain level of safety could be expected due to the longstanding use of Echinacea purpurea root preparations with no serious side effects reported.
If patients with known hypersensitivity to Echinacea, or other plants of the Asteraceae (Compositae) family are excluded (contraindication), a traditional use is possible if administration follows the instructions as specified in the monograph.
Tests on reproductive toxicity, genotoxicity and carcinogenicity have not been performed. An European Union list entry is not supported due to lack of adequate data.
Therapeutic areas for browse /search at the EMA website:
Indication 1: Cough and cold
Indication 2: Skin disorders and minor wounds
List of references