Plantago – Ribwort Plantain (Plantaginis lanceolatae folium)

Latin name of the genus:Plantago
Latin name of herbal substance:Plantaginis lanceolatae folium
Botanical name of plant:Plantago lanceolata l.
English common name of herbal substance:Ribwort plantain
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Latin name of the genus: Plantago
Latin name of herbal substance: Plantaginis lanceolatae folium
Botanical name of plant: Plantago lanceolata L.
English common name of herbal substance: Ribwort Plantain

Plantago - Ribwort Plantain - Plantago lanceolata L.

2.2.Information on traditional/current indications and specified substances/preparations . 13

2.3.Specified strength/posology/route of administration/duration of use for relevant

Table of Contents

1. Introduction

1.1. Description of the herbal substance(s), herbal preparation(s) or combinations thereof

Herbal substance(s)

Definitions of the herbal substance

European Pharmacopoeia 6th ed. 2010 (6.7): ‘Plantaginis lanceolatae folium – Ribwort plantain’ ‘Whole or fragmented, dried leaf and scape of Plantago lanceolata L.s.l.’

Deutsches Arzneibuch 2005 (DAB 2005 – German Pharmacopoeia): ‘Spitzwegerichkraut’ ‘The whole or cut, dried herb of Plantago lanceolata L.’

The monograph for ribwort plantain herb, which had appeared in the German Pharmacopoeia, has been replaced by the monograph for ribwort plantain leaf, published in the European Pharmacopoeia. Ribwort plantain herb mainly consists of leaves, therefore the title ‘Plantaginis lanceolata, folium’ has been chosen.

ESCOP Monographs 2nd ed. 2003: ‘Plantaginis lanceolatae folium/herba – Ribwort plantain leaf/herb’

‘Ribwort plantain leaf consists of the dried leaves of Plantago lanceolata L.’

‘Ribwort plantain herb consists of the dried flowering aerial parts of Plantago lanceolata L.’

Österreichisches Arzneibuch (ÖAB 90 – Austrian Pharmacopoeia 1991): ‘Folium Plantaginis, Spitzwegerichblatt’

‘The dried leaf of Plantago lanceolata L.’

Pharmacopoea Helvetica VII (Swiss Pharmacopoeia): ‘Plantaginis folium’

‘Ribwort plantain leaf consists of the dried leaf of Plantago lanceolata L. sensu latiore’

Name

Plantago lanceolata L. is a species of the genus Plantago in the Plantaginaceae botanical family, known by the following common names:

German: Spitzwegerich, Heilwegerich, Wundwegerich (Wichtl 2004);

English: Ribwort plantain, Ribwort, English plantain, Narrow-leaf plantain, Lance-leaf plantain, Ribgrass (Wichtl 2004), Tinker-tailor grass, Buckhorn plantain, Lancell, Windles (Bond et al. 2007);

French: Feuilles (herbe) de plantain (Blaschek et al. 2008);

Italian: Piantaggine (Blaschek et al. 2008).

Occurrence

Plantago lanceolata L. is a common perennial weed of arable fields and grassland (Bond et al. 2007), abundant throughout Europe, North- and Central Asia (Wichtl 2002). It is native in grassy places on neutral or basic soils (Bond et al. 2007). The herb is a common roadside plant (Bond et al. 2007) and is found in lawns (Sagar and Harper 1964). It is relatively drought resistant and is able to grow on dry sites such as embankments and chalk grassland (Bond et al. 2007).

Biology

Plantago lanceolata L. has a slight, unspecific odour similar to hay and a slightly salty and faintly bitter taste (Blaschek et al. 2008). The plant is a rosette-forming perennial herb, achieving a tallness of 5-50 cm, with a thick short rhizome and with a leafless, hairy flower stem. The basal rosette consists of 20 cm long and linear-lanceolate leaves with parallel venation. The brownish, inconspicuous flowers appear in cylindrical spikes on long stalks, protruding from the leaves. Conspicuous are the spreading, yellowish white stamens (Wichtl 2004).

Plantago lanceolata L. generally flowers from May to August (Bond et al. 2007) but flowering may begin in April and continue till the first frost (Sagar and Harper 1964). Flowers are wind pollinated although insects visit to collect pollen (Warwick and Briggs 1979).

Adulteration and confusion

Confusion with leaves of Plantago major, Plantago media or Digitalis lanata is possible (Blaschek et al.

2008).

Principal components of the herbal substance

Iridoid glycosides:

The herbal substance contains about 2-3% iridoid glycosides with aucubin and catalpol as the main compounds, as well as asperuloside, globularin and desacetylasperuloside-acid methylester. The iridoid content depends on the maturity of the leaves. Young leaves contain up to 9%, while in the older ones, iridoids are present only in traces. In young leaves, catalpol is the dominant constituent, and in older leaves, aucubin is the major compound (Wichtl 2004). Depending on the time of harvesting the content of aucubin and catalpol varies. Before the flowering period, the content of aucubin is very low in every organ and reaches its maximum in autumn (Blaschek et al. 2008), with aucubin at levels of 1- 3% and catalpol up to 1% (Long 1995, Wichtl 2004). After harvesting, the herb has to be dried directly to avoid fermentative processes. After hydrolysis, aucubin is converted to dark brown polymers, which are responsible for the dark colouration of improperly dried drug material (Wichtl 2004).

The herbal substance is commonly dried at temperatures of 40-50°C. During this process the content of aucubin decreases. Drying at room temperature results in aucubin contents twice as high (Blaschek et al. 2008).

Mucilage:

Other drug constituents include 2-6.5% mucilage. An arabinogalactan, a glucomannan and a rhamnogalacturonan with an arabinogalactan side-chain as well as a rhamnoarabinogalactan and a linear (1-6)-α-D-glucan have been isolated (Wichtl 2004).

Flavonoids:

Flavonoids include apigenin and luteolin as well as their derivatives with the main compounds apigenin- 6,8-di-C-glucoside and luteolin-7-O-glucuronide, luteolin-7-O-glucoside and 7-O-glucuronide-3′- glucoside, in addition to the 7-O-glucuronyl-glycosides of apigenin and luteolin, as well as apigenin-7- O-glucoside and 7-O-glucuronide (Wichtl 2004).

Other constituents:

The herbal substance also contains 6.5% tannins, phenolic carboxylic acids including p- hydroxybenzoic-, protocatechuic, gentisinic-, chlorogenic- and neochlorogenic acid, among others. The coumarin aesculetin, the xanthophyll decomposition product loliolide and small amounts of a hemolytic

and antimicrobial saponin are also present, as well as volatile oil. Inorganic constituents include 1% silicilic acid and mineral salts with a high proportion of zinc and potassium (Wichtl 2004).

Herbal preparation(s)

A rather broad spectrum of different herbal preparations has been marketed so far. According to the overviews of the market in the Member States of the European Union, there were herbal preparations with a well-established use status and also herbal preparations under traditional use (details from the overviews seen below). With respect to the overall evaluation of the existing data on efficacy, the monograph addresses only the traditional use (see sections 1.2 and 4.3). The following list summarises the herbal preparations from both reported categories, which fulfil the criteria for traditional use laid down in Directive 2004/24/EC and which are included in the monograph (the reference to the respective herbal preparation in the monograph is given in parenthesis). Due to the broad spectrum of existing herbal preparations, they were pooled to build a single entry if justified, because of their similarity.

Herbal preparations which have been reported to be marketed so far under well-established use:

Herbal preparations which have been reported to be traditionally used:

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.

In many countries, Plantaginis lanceolatae folium is used in combinations with other herbal substances/herbal preparations usually administered for the treatment of complaints associated with colds, or for the treatment of inflammations of the mouth and throat. The main combination substances are Thymi herba, Foeniculi fructus, Salviae folium, Primulae radix, Sambuci nigrae flos, Tiliae flos, Liquiritiae radix, Matricariae flos, Menthae piperitae herba, Althaeae radix, Rubi fruticosi folium, Lupuli flos, Serpylli herba, Salviae officinalis herba, Polygonii avicularis herba, Urticae herba, Farfarae folium, Verbasci flos, Cynosbati fructus sine semine, Gentianae radix, Pini montanae turioni, Menthae piperitae aetheroleum, Foeniculi aetheroleum and Anisi aetheroleum. This monograph refers exclusively to Plantaginis lanceolatae folium.

1.2. Information about products on the market in the Member States

According to the information provided by the National Competent Authorities the following herbal substances and herbal preparations have been on the European market. The data are derived from the overview of marketed products in Europe.

Austria:

In Austria, a syrup is prepared from Plantago lanceolata leaf according to the instructions of ÖAB 2009 is commonly used. It is administered for the treatment of catarrhs of the upper airways at a dosage of 1 tablespoon 3-4 times per day. In children a dosage of 1 teaspoon is given (BGB 1, II 2004).

As a traditional use of at least 30 years is given, this preparation was included in the monograph.

Germany:

In Germany, for herbal preparations of Plantago lanceolata both a traditional and a well-established use have been documented. Considering the requirements established by the HMPC, the data are not sufficient to support a well-established use in the monograph. Nevertheless, a traditional use of 30 years is documented for all preparations and thus all of them were included in the monograph. The only exception is the dry extract (DER 3-5:1) with the extraction solvent ethanol 20% (m/m). This extract has been on the German market only since 2004. Since the soft extract (DER 1.5-1.7:1) with the extraction solvent ethanol 20-40% (V/V), however, can be regarded as the direct precursor of this extract, it was included in the monograph as well.

Herbal preparations:

ethanol 20% m/m

8)liquid extract (1:1); extraction solvent: ethanol 24.6% V/V

9, 10, 11)

expressed juice from fresh Plantaginis lanceolatae herba (1:0.6-0.9)

12, 16)

dry extract (3-6:1); extraction solvent: water

13)soft extract (1.5-1.7:1); extraction solvent: ethanol 20% m/m

15)liquid extract (1:1); extraction solvent: ethanol 40% V/V

19)Plantaginis lanceolatae herba, cut

20)liquid extract (1:0.9-1.1); extraction solvent: ethanol 40% V/V

Since when are the preparations on the market

Indications

Poland:

Traditional use: In Poland, various herbal preparations containing Plantago lanceolata with a traditional indication are on the market. None of them, however, fulfil the requirement of a medicinal use for at least 30 years and thus inclusion in the monograph was not possible.

Regulatory status overview

MA: Marketing Authorisation TRAD: Traditional Use Registration

Other TRAD: Other national Traditional systems of registration Other: If known, it should be specified or otherwise add ’Not Known’

This regulatory overview is not legally binding and does not necessarily reflect the legal status of the products in the MSs concerned.

1.3. Search and assessment methodology

A literature research on Plantago lanceolata was performed by DIMDI and LIDOS in August 2008. The key words were “Plantago lanceolata” and “Spitzwegerich”. The literature research was updated in April 2010. Additional literature was provided by the EMA.

The regulatory status of Plantago lanceolata preparations in the EU Member States was requested on 14 October 2008. In Germany, these data were obtained by means of AMIS.

2. Historical data on medicinal use

2.1. Information on period of medicinal use in the Community

See 1.2.

2.2. Information on traditional/current indications and specified substances/preparations

The following traditional uses and posologies have been recorded for Plantago lanceolata:

Monograph Plantaginis lanceolatae herba of the German Commission E (1985)

Indications for the internal administration are catarrhs of the respiratory tract and inflammation of oral and pharyngeal mucosa. Externally applied it is used for inflammation of the skin.

The mean daily dosage is 3-6 g of the herbal substance or equivalent preparations.

ESCOP Monograph Plantaginis lanceolatae folium/herba (2003)

Indications for the oral administration are catarrhs of the respiratory tract and temporary, mild inflammations of the oral and pharyngeal mucosa.

The average daily dose in adults and elderly is 3-6 g of the herbal substance or equivalent preparations. The average daily dose for children is 1-2 g for the age 1-4 years, 2-4 g for the age 4-10 years, and 3-6 g for the age 10-16 years.

German standard registration “Spitzwegerichkraut” (1996)

For a tea from the herb of Plantago lanceolata indications are the same as listed in the monograph Plantaginis lanceolatae herba of the German Commission E.

The dosage for the tea is 3-4 cups per day. An infusion for a cup of tea is prepared with 150 ml hot water and 1.4 g of the herb which is stirred for 10-15 minutes.

For rinsing and gargling, as well as for compresses, a cold macerate is prepared 3-4 times a day, with 150 ml cold water and 1.4 g of the herb, which is stirred for 1-2 hours.

Based on literature and on the results of a survey in physicians according to Madaus (1976), Plantago lanceolata is administered in medical practise for the strengthening of mucosa and skin. It is given with very high success in diseases of the respiratory tract with severe mucous production and is also administered in diseases of the urinary bladder and gastrointestinal tract. Furthermore, its use as haemostypic and local application in wounds and ulcers has been described. The usual dosage is 3 g of

the herb for a cold macerate or hot infusion, 2-3 spoons of the juice or ½ teaspoon of the fresh plant comminution 3 times per day.

Use of Plantago lanceolata in folk medicine:

The use of Plantago lanceolata for the treatment of wounds in folk medicine extensively described by Brøndegaard (1963). Loew et al. (1997) mention Plantago lanceolata as mucilage drug which can be used against dry cough caused by pharyngitis. According to Hoppe (1975) Plantago lanceolata is used as a mucilage drug and mild expectorans. In folk medicine it is administered in catarrhs of the upper respiratory tract. Due to its positive benefit-risk-ratio Plantago lanceolata is recommended by Wegener and Kraft (1999) even for children for the treatment of moderate chronic irritative cough. Büechi and Wegener (2005) recommend the administration in moderate irritative cough as well as its topical application in cases of inflammation of the skin and mucosa.

There are further reports of the use of Plantago lanceolata in folk medicine:

In Turkey, fresh Plantago lanceolata leaves are applied to abscess to promote suppuration (Sezik et al. 2001).

In Guatemala, the herbal substance is administered in conjunctivitis/eye irritation and for the treatment of wounds, ulcers, bruises and sores (Cáceres et al. 1987).

In North-West Greece, infusions of Plantago lanceolata leaves are used for curing stomach spasms (sedative action) (Tammaro and Xepapadakis 1986).

2.3. Specified strength/posology/route of administration/duration of use for relevant preparations and indications

See 1.2. and 2.2.

3. Non-Clinical Data

3.1. Overview of available pharmacological data regarding the herbal substance(s), herbal preparation(s) and relevant constituents thereof

Plantago lanceolata has traditionally been regarded as a mucilage drug. The mucilage polysaccharides, mainly arabinose and galactose (Bräutigam and Franz 1985), are not resorbed and cover the mucosa with a protective layer against local irritations (Franz 1989, Müller-Limmroth 1980). Schmidgall et al. (2000) were the first to show moderate adhesive effects of polysaccarides from Plantago lanceolata extracts on mucus membranes by means of an ex vivo system based on porcine buccal membranes.

Beyond this, pharmacological effects are attributed to the following constituents of Plantago lanceolata (Blaschek et al. 2008, Marchesan et al. 1998a):

Iridoid glycosides: mainly aucubin and catalpol

Mucilage polysaccharides

Flavonoids: mainly apigenin and luteolin

Phenylethanoids: acteoside, plantamajoside

Phenol carboxylic acids

Tannins

In vitro and in vivo pharmacological investigations have been performed with the total extract and with isolated agents from the total extract. When not specified, the plant part is not known.

Anti-inflammatory, antioxidant, antibacterial, immunostimulant, epithelising, antitoxic and pro- coagulant effects have been observed for extracts from Plantago lanceolata (Paper and Marchesan 1999, Büechi and Wegener 2005). In addition, spasmolytic and antiviral effects have been described by the authors for pure compounds of Plantago lanceolata.

Other effects reported for isolated agents of Plantago lanceolata include anthelmintic and cytotoxic properties.

Anti-inflammatory and antioxidant effects

The anti-inflammatory efficacy of extracts from Plantago lanceolata has been investigated by means of the modified hen’s egg chorioallantoic membrane test (HET-CAM) (Marchesan et al. 1998b). Four different freeze-dried liquid extracts (28% ethanol) were used. At a 10-fold higher concentration

(500 μg/pellet vs. 50 μg) the anti-inflammatory activity of the extracts was comparable to that of hydrocortisone, phenylbutazone and sodium diclofenac.

The effects of extracts from Plantago lanceolata (leaves, flowers, roots) on mediators of inflammation have been investigated in vitro in murine macrophages (Vigo et al. 2005). They inhibited the production of nitric oxide in this cell line and significant scavenging of nitric oxide radicals. Pre- treatment with these extracts did not affect COX-1 mRNA production, COX-2 mRNA and PGE2 levels induced by lipopolysaccharide/interferon-γ challenge. The authors assume that the anti-inflammatory effects of Plantago lanceolata extracts are based on the inhibition of nitric oxide and not a reduced prostaglandin production.

Herold et al. (2003a) investigated in vitro if a standardised hydroalcoholic extract from Plantago lanceolata leaves can suppress in cell-free systems the activities of 5-lipoxygenase and COX-2 which are key enzymes in the formation of pro-inflammatory eicosanoids from arachidonic acid. The Plantago lanceolata extract displayed significant efficacy concerning a dose-dependent inhibition of COX-2 activity.

In vivo studies with dried frozen extracts from Plantago lanceolata leaves showed that in Wistar–Albino mice, the inflammatory effects caused by carrageenan and prostaglandin E1 were reduced (Shipochliev et al. 1981). In Wistar rats, an 80% ethanol extract from dried Plantago lanceolata leaf reduced carrageenan-induced foot oedema by 11% (Mascolo et al. 1987).

Anti-inflammatory properties have also been established for single compounds of Plantago lanceolata by means of in vivo and in vitro experiments. The phenylethanoids acteoside and plantamajoside (Murai et al. 1995, Ravn et al. 1990, Hausmann et al. 2007, Hayashi et al. 1994, Molnár et al. 1989) and the iridoidglycosides catalpol and aucubin (Recio et al. 1994) showed anti-inflammatory activity (in vitro and in vivo investigations). For flavonoids, anti-inflammatory effects have been described too (Spilková and Hubík 1988, Mascolo et al. 1988, Tordera et al. 1994).

In connection with the anti-inflammatory activity of Plantago lanceolata, its antioxidant properties have also been studied, since free radicals may play a role in inflammatory diseases.

Herold et al. (2003b) investigated the possible mode of action of the antioxidant potential of a hydroalcoholic extract from Plantago lanceolata leaves standardised to mucilaginous substances. The antioxidant property was measured using a colorimetric assay and the free radical scavenging potential by means of activated human polymorphonuclear neutrophils (PMNs). For the extract, a minor antioxidant status and the capacity of scavenging free radicals released by activated PMNs were observed.

The antioxidant activity of a methanol extract from the aerial parts of Plantago lanceolata was studied by Gálvez et al. (2005) using the DPPH scavenging test and lipid peroxidation inhibition assay, in which this extract was found to be the most active as compared to methanol extracts from other Plantago species.

Antioxidant effects have also been observed for single compounds such as acteoside (Ji et al. 1993, Pan and Hori 1996, Wang et al. 1996; Li et al. 1996, Hausmann et al. 2007), various polysaccharides (Kardosová and Machová, 2006) and flavonoids (Catapano 1997, van Acker et al. 1996, Fraga et al. 1987).

Antibacterial effects

In vitro investigations with pressed juice and aqueous extracts of Plantago lanceolata showed antibacterial effects against Staphylococcus aureus, Streptococcus β-hemolyticus, Proteus vulgaris, Salmonella, Shigella, Pseudomonas aeruginosa, Klebsiella pneumoniae and Bacillus subtilis (Haznagy 1970, Felklova 1958, Elich 1962). An ethanolic maceration showed an in vitro inhibition of

Staphylococcus aureus (Cáceres et al. 1987).

It is assumed that aucubigenin is responsible for the in vitro antibacterial effects of Plantago lanceolata (Elich 1962, Hänsel 1966, Elich 1966, Elich 1961), as aqueous extracts with inactivated β-glucosidase showed to be ineffective (Elich 1966, Elich 1961). β-glucosidase is the relevant enzyme which splits aucubin into glucose and aucubigenin.

The antibacterial and antifungal activity of an ethanolic extract from Plantago lanceolata were also investigated by Orhan et al. (2002) by agar diffusion and microdilution methods using E. coli, Proteus mirabilis, Enterococcus faecalis, Acinetobacter baumanni, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumonia, Candida albicans, Candida kruzei and Candida parapsilosis. Antibacterial or antifungal effects were not observed for Plantago lanceolata.

Regarding single compounds of Plantago lanceolata acteoside exerted only weak antibacterial effects on E. coli (Molnár et al. 1989). The isolated compounds aucubin and saponin and extract of the Plantago lanceolata leaves showed antibiotic effect. Extract of Plantago lanceolata leaves and aucubin had antibiotic effects on Streptococcus aureus 209 P and Micrococcus flavus, whereas the antibiotic activity of the saponin compound was limited to Micrococcus flavus (Tarle et al. 1981).

Spasmolytic effects

An ethanolic extract from Plantago lanceolata herba (DER 1:1) (Fleer et al. 1997) and an ethanolic (20%) soft extract of Plantago lanceolata (Fleer and Verspohl 2007) inhibited the ileum contractions caused by acetylcholine, histamine, potassium and barium ions and barium induced tracheal contractions in guinea-pigs. These effects were comparable to those of atropine and papaverine.

Spasmolytic activity has been attributed to the iridoids aucubin and catalpol (Urbina et al. 1994) and acteoside (Schapoval et al. 1998). Fleer and Verspohl (2007) observed antispasmodic effects for luteolin, acteoside, plantamajoside and catalpol peracetate.

Antiviral effects

Abdin (2006) observed positive effects of tea from Plantago lanceolata leaves in one patient with AIDS- related complex and suggests that further research might explore a possible role for Plantago lanceolata in the treatment of HIV-infection.

Antiviral effects on Aujezky virus (Molnár et al. 1989) and RS-virus (Kernan et al. 1998) were observed for acteoside. Aucubin, as a prodrug for aucubigenin, inhibited in vitro DNS-replication of hepatitis B

virus (Chang 1997). Catalpol showed to be active against hepatitis B virus antigens (HBsAg) in HBsAg positive serum (Mehrotra et al. 1990). For caffeic acid and chlorogenic acid (Chattopadhyay et al. 2008, Zanon et al. 1999, Chiang et al. 2002) as well as saponins and tanning agents (Büechi 1998, Büechi 1996) antiviral activity was shown, too.

Antitoxic effects

Protective effects have been attributed to Plantago lanceolata. It has been reported that pressed juice from Plantago lanceolata had antitoxic effects on the damaging effects of 5-fluoruracil on the mucosa in mice with Ehrlich-tumours (Zueva and Yaremenko 1989, Borovskaya et al. 1987). Celik and Aslantürk (2006) also observed in vitro anti-mitotic and anti-genotoxic effects with aqueous extracts from Plantago lanceolata leaves.

Antitumor activity was observed in vitro for acteoside and seems to be due at least in part to inhibition of protein kinase C (Herbert and Maffrand 1991). Flavonoids were shown to inhibit tumour promoter- induced histamine release in a concentration-dependent manner (Middleton et al. 1987) and to inhibit hyaluronidase (Kuppusamy et al. 1990) and cyclic AMP phosphodiesterase (Kuppusamy and Das 1992).

The hepatoprotective activity of an ethanolic extract from Plantago lanceolata leaves was investigated using pentobarbital-induced hypnosis model in mice treated with carbon tetrachloride as hepatotoxin. Significant hepatoprotective effects (25.5% inhibition) were observed (Deliorman et al. 1999). In a study performed in rats, however, the extract from Plantago lanceolata leaves showed no protective efficacy in hepatotoxicity caused by carbon tetrachloride (Aktay et al. 2000). In another in vitro investigation by Aktay et al. (2001), an ethanolic extract from Plantago lanceolata leaves showed no inhibition of lipid peroxidation, which is implicated as a molecular mechanism in the pathogenesis of several chronic diseases.

Hepatoprotective effects were observed for aucubin (Chang et al. 1984a, Chang et al. 1984b, Chang and Yamaura 1993), acteoside (Xiong et al. 1998, Yamahara et al. 1990, Pan and Hori 1996) and catalpol (Garg et al. 1994).

Immunostimulant effects

In vitro and in vivo, an aqueous extract from Plantago lanceolata leaves caused a significant increase of antibody formation and release of angiogenesis factor in lymphocytes of man and mouse (Strzelecka et al. 1995). An aqueous decoction of Plantago lanceolata leaves stimulated the production of interferon in mice (Plachcinska et al. 1984).

Immunomodulatory effects were shown for several compounds of Plantago lanceolata: polysaccharides derived from Plantago lanceolata leaves (Bräutigam 1985, Ebringerová et al. 2003), aucubin and chlorogenic acid (Chiang et al. 2003), catalpol (Wegener and Kraft 1999, Garg et al. 1994) and acteoside (Marchesan et al. 1998). For acteoside, immunosuppressive effects were reported by Sasaki et al. (1989).

Epithelising effects

Aqueous extracts from Plantago lanceolata are said to promote epithelising and scaring of wounds and to reduce hyperemia (Blaschek 2008, Heil and Kammerer 1993). According to Pahlow (1984) fresh ground Plantago lanceolata leaves are effective in inflammation or irritation of the skin caused by insect stings (Brøndegaard 1963).

Müller-Limmroth and Fröhlich (1980) report that aucubin supports the epithelisation of defects in bronchial mucosa, whereas the mucopolysaccharides contained in Plantago lanceolata cover epithelial defects in the hypopharynx which are responsible for triggering the cough reflex.

Pro-coagulant effects

Aqueous extracts increased coagulation in vitro and in vivo (Blaschek et al. 2008, Keeser 1939). An extract (1:1) stimulated the coagulation of blood in rabbits, a 1:10 infus. reduced coagulation time in dilutions of 1:5 to 1:40. Following injection into the femoral vein (v. femoralis) of the cat, an acceleration of coagulation was observed.

Anthelmintic effects

Ethanolic and aqueous extracts from Plantago lanceolata leaves displayed significant anthelmintic activity against pinworms in mice (Kozan et al. 2006).

Cytotoxic effects

Cytotoxic effects for single compounds of Plantago lanceolata have been observed by Gàlvez et al. (2003). Methanolic extracts from Plantago lanceolata leaves showed growth inhibitory and cytotoxic effects in vitro on breast adenocarcinoma and melanoma tumoral cell lines, which might be due to the cytotoxic activity of the flavone luteolin-7-O-β-glucoside, a major flavonoid in Plantago species. According to the authors, topoisomerase-mediated DNA damage is the possible mechanism of cytotoxicity.

In an in vitro investigation in rat hepatoma cells, an increased breaking of DNA chains as well as increased proapoptoctic effects occurred following luteolin concentrations > 100 μM (Steffan 2005). In contrast to this observation for flavonoids, anticancerogenic effects have been described after in vitro concentrations of 0.1-1 mM (Watzl and Rechkemmer 2001).

A saponin substance (not identified) isolated from the leaves of Plantago lanceolata showed haemolytic activity (Tarle et al. 1981).

Effects on mucociliary transport

Mucociliary transport was investigated by viscosimetry using a ciliated epithelium preparation of a frog. A 4.6% extract from Plantago lanceolata did not increase mucociliary activity (Müller-Limmroth and Fröhlich 1980).

3.2. Overview of available pharmacokinetic data regarding the herbal substance(s), herbal preparation(s) and relevant constituents thereof

There is a report on the pharmacokinetics of aucubin in rats (Suh et al. 1991). Linear kinetics were observed following the intravenous administration of 40-400 mg/kg bodyweight. Post-distributional half-life t1/2,β was 43 minutes. Binding capacity to plasma proteins was 9%. For a dose of 100 mg/kg bodyweight, bioavailability was 83.5% (hepatoportal application), 76.8% (intraperitoneal application) and 19.3% (oral application). Investigations regarding the stability of pH at a temperature of 37°C showed a fast degradation of aucubin at pH values of 1.2, 1.6 and 2.0 with half-lives of 5.1, 5.8 and 14.8 h. The authors thus assume that the low bioavailability of aucubin may be explained by its instability at a low pH, the low gastrointestinal absorption and an intensive first-pass metabolism.

In rabbits, aucubigenin accumulates in urine when fed with the drug (Freerksen 1950).

3.3. Overview of available toxicological data regarding the herbal substance(s)/herbal preparation(s) and constituents thereof

No acute or chronic toxicity tests were performed on any of the herbal preparations of Plantago lanceolata included in the monograph.

Acute toxicity

Aucubin can cause gastroenteritis and central palsy following oral administration (Blaschek et al. 2008).

Following maximum aucubin doses of 900 mg/kg bodyweight, no deaths occurred in mice (Chang 1985).

Chronic toxicity

Maximum aucubin doses of 800 mg/kg bodyweight 4 times a week did not cause significant changes of liver transaminases, alkaline phosphatase, triglycerides, glucose, blood urea nitrogen and total protein. Liver biopsies did not reveal relevant changes (Chang 1985).

Mutagenicity and cancerogenicity

An Ames-test was performed with a tincture (1:5) from Plantago lanceolata (70% ethanol). Both with and without metabolic activation by the S-9 fraction, mutagenic effects were not observed with the Salmonella typhimurium TA 98 and TA 100 (Schimmer et al. 1994).

Ruiz et al. (1996) screened several plants for genotoxic activity by means of induction of somatic segregation in Aspergillus nidulans. A fluid extract from Plantago lanceolata (40% ethanol) showed no statistically significant increase in the frequency of segregant sectors per colony and thus no genotoxic effects.

Cytotoxicity

Cytotoxic effects of a methanol extract from Plantago lanceolata were observed by Gàlvez et al. (2003); haemolytic activity was described by Tarle et al. (1981) for a saponin substance isolated from the leaves of Plantago lanceolata. In an in vitro investigation in rat hepatoma cells, an increased breaking of DNA chains as well as increased proapoptoctic effects occurred following luteolin concentrations > 100 μM (Steffan 2005) (see section 3.1).

Local tolerance

In an investigation with 1000 dogs, Plantago lanceolata caused atopic dermatitis in > 15% of the animals (Mueller et al. 2000).

3.4. Overall conclusions on non-clinical data

Pharmacology

A variety of pharmacological effects have been reported for Plantago lanceolata extracts and other preparations and for its compounds. Most of the investigations are quite old, while more recent investigations have mainly been performed with isolated compounds of the plant. As so far, only the concentration of the iridoid glycosides aucubin and catapol has been determined (Long et al. 1995, Jurisic et al. 2004), it is not possible to assess to which extent the different reported effects of Plantago lanceolata extracts could be attributed to these single compounds.

The pharmacological effects described in literature, however, support both the oral and oromucosal traditional use of herbal preparations of Plantago lanceolata as a demulcent for the symptomatic treatment of irritations of oral and pharyngeal mucosa with associated dry cough.

Pharmacokinetics

So far, pharmacokinetic investigations have only been performed with aucubin and not with the total extract.

Data on pharmacokinetics in man are not available. Due to the low bioavailability of aucubin, it is unclear to which extent the pharmacological effects observed in vitro and in vivo experiments contribute to the efficacy of the total extract and are of clinical relevance.

Toxicology

There are no data available on the toxicity tests with preparations from Plantago lanceolata. No reproduction or developmental toxicity tests have been performed. An administration of Plantago lanceolata thus cannot be recommended during pregnancy and lactation. The investigation of genotoxiciy by Schimmer et al. (1994) is assessed as insufficient, as the Ames test performed included only 2 stems of Salmonella typhimurium instead of 5 as required.

Regarding the cytotoxic effects observed for luteolin, it is supposed that there is no risk in man, as the bioavailability of flavonoids following oral administration is only poor and only low concentrations of the mutagenic active flavonoids can be found (Teuscher et al. 2004). The luteolin concentration used in the in vitro experiments thus is not reached under physiological conditions.

With regard to the potential toxicity of aucubin, its minimum lethal dose in mouse of > 0.9 g have to be taken into account so that aucubin is regarded as a low toxic substance (Chang et al. 1983). Due to the low content of aucubin in Plantago lanceolata, the safety of the herbal substance does not seem to be affected when used in clinical practice and intoxications with Plantago lanceolata have not been observed.

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

No human data available.

4.1.2. Overview of pharmacokinetic data regarding the herbal substance(s)/preparation(s) including data on relevant constituents

No human data available.

4.2. Clinical Efficacy

4.2.1. Dose response studies

Dose response studies have not been performed.

4.2.2. Clinical studies (case studies and clinical trials)

There is only one post-marketing study conducted by Kraft (1997). The aim of this prospective, multicenter study was to obtain data on the administration of a cough syrup (100 ml syrup contains 20 g fluid extract from Plantago lanceolata herb, DER 1:1, extraction solvent ethanol) and to assess its efficacy and safety in patients with unspecific acute respiratory diseases. For the assessment of therapeutic course, subjective symptoms, efficacy and tolerability were rated by the patient and the doctor by means of scores from 0-5.

A total of 593 patients (mean age 42 years, range 1-88 years) were included, in 15% of the patients age was < 18 years. The main diagnoses were acute respiratory infections (32% of the patients), acute bronchitis (28%) and irritative cough following acute respiratory infections (18%). The mean duration of administration of the cough syrup was 10 days with a mean daily dose of about 30 ml of the syrup corresponding to about 6 g of the herbal substance.

After 3-14 days of treatment intensity and frequency of coughing was reduced by 67% and 66%, respectively. Thoracal pain decreased by 80%, irritative cough and dyspnea by 69%. Subjective finding and general condition as assessed by the doctor improved by 43% and 37%, respectively. Global efficacy was assessed as good by the doctor in 62% of the patients, and as excellent by 26% of the patients. Moderate to insufficient efficacy was reported by about 13% of the patients, whereby the assessments by patients and doctors showed great similarity.

As controlled clinical trials with extracts from Plantago lanceolata have not been performed a well- established use cannot be accepted. The results of the post-marketing study and references in literature, however, support the traditional use of Plantago lanceolata.

4.2.3. Clinical studies in special populations (e.g. elderly and children)

The results of the post-marketing study by Kraft (1997) were analysed separately for the subgroup of 91 patients with an age < 18 years (Kraft 1998). Twenty children were ≤7 years, 38 children had an age between 8 and 12 years and 33 children were adolescents between 13 and 17 years old. The mean daily dosage in this group was 22.4 ml of the syrup (corresponding to about 4.5 g of the herbal substance), the mean duration of administration 9 days. As compared to baseline symptoms decreased by 58% on average. The patients’ and doctors’ final assessments of efficacy were comparable to those of the adults.

A dosage recommendation for children is given by the Kooperation Phytopharmaka (1998) and was calculated on basis of the dosage for adults which correspond to the dosage as defined in the monograph of the Commission E. The mean daily dose of the herbal substance for children is as follows (internal administration):

Age (years)

0-1:

 

>1-4:

1-2 g

 

<4-10:

2-4 g

 

>10-16:

3-6 g

The mean daily dose for children based on the results obtained by a survey in 31 doctors are as follows (internal administration):

In children only data for the oral administration are available.

4.3. Overall conclusions on clinical pharmacology and efficacy

Controlled clinical studies, which might support a well-established use, have not been performed with

Plantago lanceolata.

The traditional use, however, is well documented. Apart from the results of one post-marketing study in 593 patients mainly with acute respiratory infections, among them 91 children and adolescents below 18 years of age (58 and 33 respectively), there is sufficient evidence in literature for the traditional internal use of Plantago lanceolata as a mucilage in the treatment of irritations of oral and pharyngeal mucosa and associated dry cough. Since the mucilage polysaccharides are not resorbed and most probably do not reach the trachea or bronchi, the medicinal use only in the upper departments of the respiratory tract seems plausible. The data available support a safe oral administration in adults and children older than 3 years. Due to the lack of sufficient data and safety considerations (see chapter 3.4), the oral use in children younger than 3 years cannot be recommended. There is also sufficient evidence in literature on the traditional oromucosal use of Plantago lanceolata in adults; for children and adolescents no data are available. Thus, the oromucosal administration should be limited to adults.

In literature there is also evidence of a traditional use of Plantago lanceolata for the external treatment of irritations of the skin, but so far only one medicinal product has been registered in Poland. This preparation, however, does not fulfil the requirement of a traditional use for at least 30 years.

5. Clinical Safety/Pharmacovigilance

5.1. Overview of toxicological/safety data from clinical trials in humans

In the post-marketing study by Kraft (1997), tolerability of the syrup from Plantago lanceolata (see chapter 4.2.2) was assessed as excellent by 49% of the patients and 51% of the doctors. The assessment “moderate” was given by about 2% of the patients and doctors. Adverse events were rare and of low severity. In 7 patients (1%), adverse events were recorded, 5 of them were diarrhoea – among them one child (age 10 years) – occurring in one centre only. In 6 cases, a causal relationship of the adverse event with the medication was assumed. Allergic reactions were not reported. Since all cases of diarrhoea occurred in one centre only the investigator suspected that this adverse event had an infectious cause.

So far, side-effects with Plantago lanceolata have not been reported in literature. Neither the monograph of the Commission E (1985) nor the ESCOP monograph (2003) mentions adverse reactions.

Nevertheless, for Plantago lanceolata a high risk of sensitisation is reported by Blaschek et al. (2008). About 30% of patients with pollinosis are allergic to pollen from Plantago lanceolata (Wüthrich et al. 1977, Horak and Jäger 1980). Twenty-eight percent of the 82 patients, with a clinical history of seasonal, respiratory allergy, were skin test positive to plantain pollen extract, 34% of serum samples of 354 similar patients showed positive RAST (radio-allergo-sorbens-test) results (Mehta and Wheeler 1991). Since extracts from Plantago lanceolata do not contain pollen and the preparations are not inhaled, allergic reactions due to these preparations are unlikely.

One report of an allergic adverse event was received by the German Health Authority. Following the intake of a medicinal product containing Plantago lanceolata, a 35-year old patient developed angio- oedema, swelling of eyes and lips and urticaria. As several medications were administered to the patient, the causal relation cannot be assessed definitely.

5.2. Patient exposure

Apart from its medicinal use, Plantago lanceolata is also available on the food-market in form of e.g. sweets and teas. It is also used in cosmetics. There is no information available on the extent of its use in the general population.

5.3. Adverse events and serious adverse events and deaths

See chapter 5.1.

5.4. Laboratory findings

None reported for Plantago lanceolata.

5.5. Safety in special populations and situations

See chapter 5.1.

5.6. Overall conclusions on clinical safety

The oral and oromucosal administration of Plantago lanceolata is generally recognised as safe. Due to the lack of adequate data, however, its use cannot be recommended during pregnancy and lactation. In children younger than 3 years, Plantago lanceolata and preparations thereof should not be used, as there are only limited data on the oral use in children. In addition, in relation to children of this age, a doctor should be consulted to make a diagnosis before the start of treatment, otherwise there is a risk that severe infectious diseases of the upper respiratory tract, such as laryngitis, are misinterpreted as a common cold. Data on a safe oromucosal application in children and adolescents are missing, too.

The cutaneous use of Plantago lanceolata is not recommended at all, since data on the topical application are completely missing.

6. Overall conclusions

The use of Plantago lanceolata as demulcent in the symptomatic treatment of oral and pharyngeal irritations and associated dry cough fulfils the requirement of at least 30 years of medicinal use (including at least 15 years with the European Union) according to the traditional use provisions of Directive 2001/83/EC as amended.

There is sufficient evidence in literature for the traditional oral and oromucosal use in the above mentioned indication. Although various pharmacological effects have been described for the total extract of Plantago lanceolata and constituents thereof, these effects have never been verified in controlled clinical studies. A well-established use of the herbal substance thus cannot be postulated.

The oral administration has been investigated in a post-marketing study in 598 patients which confirms the safe use in elderly, adults, adolescents and children between 3 and 12 years of age. As there are only limited data on the use of Plantago lanceolata in children < 3 years and due to their special medical conditions, oral use is not recommended for this age group.

The oromucosal administration is recommended only for elderly and adults, as data in children and adolescents are completely missing.

Due to the lack of data of its safe administration during pregnancy and lactation, this patient group should also be excluded from administration.

An incomplete Ames-test is only available for a tincture of Plantago lanceolata. The inclusion of the preparations of Plantago lanceolata in the Community list of herbal substances, preparations and combinations thereof for use in traditional herbal medicinal products thus cannot be recommended.

Annex

List of references

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