Taraxacum – Dandelion Leaf (Taraxaci folium)
|Latin name of the genus:||Taraxacum|
|Latin name of herbal substance:||Taraxaci folium|
|Botanical name of plant:||Taraxacum officinale weber ex wigg.|
|English common name of herbal substance:||Dandelion leaf|
Latin name of the genus: Taraxacum
Latin name of herbal substance: Taraxaci folium
Botanical name of plant: Taraxacum officinale Weber ex Wigg.
English common name of herbal substance: Dandelion Leaf
- 1. Introduction
- 2. Historical data on medicinal use
- 3. Non-Clinical Data
- 3.1. Overview of available pharmacological data regarding the herbal substance(s), herbal preparation(s) and relevant constituents thereof
- 3.2. Overview of available pharmacokinetic data regarding the herbal substance(s), herbal preparation(s) and relevant constituents thereof
- 3.3. Overview of available toxicological data regarding the herbal substance(s)/herbal preparation(s) and constituents thereof
- 3.4. Overall conclusions on non-clinical data
- 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
- 4.1.2. Overview of pharmacokinetic data regarding the herbal substance(s)/preparation(s) including data on relevant constituents
- 4.2. Clinical Efficacy
- 4.2.1. Dose response studies
- 4.2.2. Clinical studies (case studies and clinical trials)
- 4.2.3. Clinical studies in special populations (e.g. elderly and children)
- 4.3. Overall conclusions on clinical pharmacology and efficacy
- 5. Clinical Safety/Pharmacovigilance
- 6. Overall conclusions
1.1. Description of the herbal substance(s), herbal preparation(s) or combinations thereof
Dandelion leaf consists of the dried leaves of Taraxacum officinale Weber, Compositae, collected before flowering (Bradley PR 1992).
Dandelion leaf consists of the dried leaves of Taraxacum officinale Weber collected before flowering (British Herbal Pharmacopoeia 1996).
Dandelion leaf consists of the dried leaves of Taraxacum officinale Weber s.l., collected before the flowering period (ESCOP monographs 2003).
In ethanolic extracts prepared in a Soxhlet apparatus, ca. 0.59% of
– sitosterol (Kuusi et al. 1985) also were found.
Two sesquiterpenes, taraxinic
T. officinale leaves contain a high potassium concentration. In a
Trace metals, determined in wild growing plants from 29 sites in USA by inductively coupled plasma atomic emission spectrometry
– 3916, Mn 21.70 – 276.95, Ni 2.15 – 38.02, Pb 0.50 – 45.00, and Zn 18.60 – 261.40 (Keane B et al. 2001).
In another study, in samples from 13 sites in Poland, levels (mg/kg) of Cd 0.04 – 0.27, Cu 1.5 – 8.7, Pb 3.3 – 175.3 and Zn 7.9 – 103.6 were determined by FAAS (Królak E 2003).
519 mg/l of potassium were found in an infusion (prepared by using 5 g of dandelion leaves from Spain in 200 ml of water at 70°C during 2 hrs) by
a)dried leaves (British Herbal Pharmacopoeia 1996)
b)liquid extract (1:1) extraction solvent ethanol 25% (V/V) (British Herbal Pharmacopoeia 1996)
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. Information about products on the market in the Member States
Regulatory status overview
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
The electronic databases of Pubmed, Scopus and International Pharmaceutical Abstracts were searched with the search terms ‘Taraxacum officinale’ combined with ‘human’, ‘clinical trial’ , ‘Randomised Controlled Trial’ and ‘Review’.
2. Historical data on medicinal use
2.1. Information on period of medicinal use in the Community
The monograph Taraxaci folium is discussed in HagerROM 2006. However, the synonyms Taraxaci herba and Herba taraxaci (according German Commission E – Blumenthal M et al. 1998) are mentioned, too. In the later reference, dandelion herb consists of the fresh or dried
Three preparations from Taraxaci folium could be found in literature. A period of at least 30 years in medical use as requested by Directive 2004/24 EC for qualification as a traditional herbal medicinal product is fulfilled for Taraxaci folium.
In parallel to the medicinal use, dandelion inflorescences, leaves and roots are processed into different food products. Young leaves of cultivated or wild species are consumed fresh as salad. Additionally, extracts are used as flavour components in various food products, including alcoholic beverages and soft drinks, frozen dairy desserts, candy, baked goods, gelatins and puddings and cheese (Rivera- Núňez 1991; Leung and Foster 1996).
Type of tradition, where relevant
2.2. Information on traditional/current indications and specified substances/preparations
The following indications have been reported for Taraxaci folium:
As an adjunct to treatments where enhanced urinary output is desirable, e.g. rheumatism and the prevention of renal gravel (Weiss RF 1991).
Water retention due to various causes, insufficient production of bile (Bradley PR 1992).
2.3. Specified strength/posology/route of administration/duration of use for relevant preparations and indications
Evidence regarding the specified posology
Dried leaves daily
Evidence regarding the route of administration
The oral administration is the only route for Taraxaci folium preparations in the recommended traditional indications.
Evidence regarding the duration of use
No restriction on the duration of use has been reported for Taraxaci folium. As clinical safety studies are lacking, the duration of use is limited to 2 weeks.
Assessor’s overall conclusion on the traditional medicinal use
Preparations from Taraxaci folium have been used for diuresis stimulation. The traditional medicinal use is made plausible by pharmacological data.
3.1. Overview of available pharmacological data regarding the herbal substance(s), herbal preparation(s) and relevant constituents thereof
According to the British Herbal Pharmacopoeia (1996), a diuretic action is described for the leaves.
The diuretic action of aqueous extracts obtained from dandelion leaves was reported to be more pronounced than that from the root extracts (administered through a gastric tube to male rats at a dose of 50 ml/kg body weight). The highest diuretic and saluretic indices corresponded to 8 g dried herb/kg body weight. Comparable diuretic and saluretic indices were reached with furosemide at 80 mg/kg body weight. The very high saluretic index concerning potassium excretion may be due to the high (4.25%) potassium content
Theoretically, patients on lithium therapy who use herbal preparation wit a diuretic action (e.g. dandelion) may experience dehydration and resulting lithium toxicity (Harkness R and Bratman S 2003).
After intraduodenal administration water decoction from Taraxacum leaves in rats, the bile volume per hour increased by a maximum of 40% (Böhm K 1959).
A decoction from 5 g of dried leaves resulted, after intravenous administration to dogs, in a twofold increase of the bile volume during a
Extract of Taraxacum officinale methanol leaf exhibited a 69% inhibition, in the
Per os (p.o.) administration of a decoction from aerial parts of Taraxacum officinale (10 mg/kg), followed by 75 µg/kg cholecystokinin (CCK) octapeptide injected subcutaneously three times after 1, 3 and 5 h for 5 days significantly decreased the pancreatic weight/body weight ratio in CCK octapeptide- induced acute pancreatitis. The treatment also increased the pancreatic levels of HSP60 and HSP72, and decreased the secretion of
An ethanolic extract (ethanol 70%) from dried aerial parts produced a
The opposite effect, an increase of NO production through an increased amount of inducible NO synthase protein was observed after stimulation of mouse peritoneal macrophages with water decoction from the aerial parts of Taraxacum officinale after the treatment of recombinant interferon- (rIFN- ). The increased production of NO from rIFN- plus
A water extract from aerial parts of Taraxacum officinale is reported to inhibit
A water infusion from a
A possible insulin release from
No effect on ADP
Effects of dandelion water lyophilisates on Wistar rats liver microsomes were studied (Hagymási K et al. 2000a). The malondialdehyde products were decreased by folium extracts, in a
The same authors described also the
Antioxidant effects of flower, leaf, stem and root were observed for all dandelion extracts investigated by measuring liposomal lipid peroxidation induced by Fe2+ and ascorbic acid, with the exception of the ethyl acetate extract from flowers, in combination with CCl4, the chloroform and aqueous extract from stems, either alone or in combination with CCl4, and the aqueous extract from roots, either alone or in combination with CCl4. Fullerenol exhibited an
The same authors studied inhibition of hydroxyl radical production by different dandelion extracts. Pronounced inhibitory effects were obtained using chloroform and ethyl acetate extracts of leaves (Kaurinovic B et al. 2003).
Pharmacological activities of some constituents
Taraxinic acid (an aglycone from taraxinic
A high intake of chlorogenic acid may be associated with markedly lower risk for diabetes by a decrease of carbohydrate absorption and an inhibition of intestinal glucose transport (Welsch CA et al. 1989, Johnston KL et al. 2003). Chlorogenic acid inhibits
Bitter principles are reported to enhance excretion from salivary and stomach glands by reflectory irritation of bitter receptors (Wagner H and Wiesenauer M 1995). Taraxinic acid
Assessor’s overall conclusions on pharmacology
Pharmacological activities of leaves extracts contribute to support the traditional use of preparations containing Taraxaci folium in the proposed indication.
3.2. Overview of available pharmacokinetic data regarding the herbal substance(s), herbal preparation(s) and relevant constituents thereof
No data available.
3.3. Overview of available toxicological data regarding the herbal substance(s)/herbal preparation(s) and constituents thereof
The effects of unspecified part(s) of dandelion on tumours was investigated in mice with subcutaneously transplanted tumours (Ehrlich adenocarcinoma, Lewis lung carcinoma – LLC). The effects of chemotherapy with cyclophosphamide was evaluated by tumour weight, percentage of tumour growth inhibition (GI), number of metastases in lungs and their area, and incidence of
metastasing by index of metastases inhibition (IMI). Dandelion extract did not modify metastatic process when it was used alone (IMI = 57%, GI = 21%), but increased the efficiency of cytostatic therapy (IMI = 77%, GI = 30%). Effects for extract without cyclophosphamide were negligible (IMI = 4%, GI = 11%). In the LLC model, dandelion extract decreased the number of animals with metastases from 100% to 67%, and the number of metastatic nodes in the lungs per animal from 34.4 to 4.1. Water soluble polysaccharides were identified as potentially active substances (Goldberg ED et al. 2004, Lopatina KA et al. 2007).
In another study, aqueous extract was prepared from the leaves of Taraxacum officinale, and investigated on tumour progression related processes such as proliferation and invasion. The results showed that the water extract of dandelion leaf (DLE) decreased the growth of
No visible signs of acute toxicity were identified after oral administration of
Different types of extracts presented low toxicity when administered: a fluid herb and root extract showed intraperitoneal LD50 of 28.8 and 36.6 g/kg body weight, respectively, in mice
Hyperkalemia related issues
Under normal physiological conditions, potassium balance is maintained by mechanisms that match potassium excretion to potassium intake mainly through the kidney. In healthy adults, the serum potassium level is controlled within the narrow range of 3.5 to 5.0 mEq/l, irrespective of the dietary potassium intake. Potassium is excreted very rapidly after large intake, e.g. 200 mmol/day, when given orally with only a small increase in plasma potassium (He FJ and MacGregor GA 2008).
Hyperkalemia may occur when the regulatory mechanisms are impaired, particularly in patients with impaired renal function or in some patients with diabetes (Evans KJ and Greenberg A 2005). The development of hyperkalemia requires the concomitant malfunction at least of one of the mechanisms that maintain potassium homeostasis. The factors that can affect these homeostatic mechanisms and result in hyperkalemia can be divided into four categories:
1.decrease in kidney potassium excretion due to acute or chronic renal failure, adrenal insufficiency, burns, bleeding into gastrointestinal tract, hyporeninemic hypoaldosteronism, potassium therapy, secretion tissue injury, suppression of insulin
2.transcellular potassium movement (acute tumour lysis, exercise, hyperglycemia, hyperkalemic familial periodic paralysis, insulin deficiency, intravascular hemolysis, metabolic acidosis, rhabdomyolysis)
4.increase in potassium load – the recommended intake of potassium for healthy adolescents and adults is 4,700 mg/day. Recommended intakes for potassium for children 1 to 3 years of age is
3,000 mg/day, 4 to 8 years of age is 3,800 mg/day, and 9 to 13 years of age is 4,500 mg/day (Dietary Guidelines for Americans 2005).
However, an increase in plasma potassium to levels above 5.5 mM is uncommon until over 90% of the renal function is lost and glomerular filtration rate is less than 20 ml/min. The incidence of hyperkalemia in the general population is unknown. In hospitalised patients, the incidence ranges from 1.3% to 10%. Impaired kidney function is the major risk factor for development of hyperkalemia and is present in 33% to 83% of all cases (Evans KJ and Greenberg A 2005).
In addition to renal function, there are several other factors that also influence plasma potassium, e.g.
Severe hyperkalemia that develops during
According to the guidelines for the diagnosis and treatment of chronic HF, potassium levels should be < 5 mmol/l to warrant the addition of
Cardiac glycosides are indicated in atrial fibrillation and any class of symptomatic HF. Hyperkalemia depolarizes the myocytes and strengthens the suppressive effect of digoxin on the atrioventricular node (Macdonald JE and Struthers AD 2004).
Hyperkalemia may be due to digitalis toxicity, and it is believed to result from inhibition of the
Patients with HF are at high risk of thromboembolic events. Heparin can cause hyperkalemia by blocking the synthesis of aldosterone. However, severe hyperkalemia occurs in the presence of additional factors affecting potassium homeostasis. While the principle of the treatment is to discontinue the heparin, it is first recommended to discontinue other
Diabetes is a well known condition that increases the risk of hyperkalemia. Extracellular potassium is taken up intracellularly by insulin action. In diabetes in which the insulin action is insufficient or deficient, the serum potassium level increases (Jarman PR et al. 1995; Ahuja TS et al. 2000). Additionally, about 40% of patients with type 1 or type
519 mg/l of potassium were found in an infusion prepared by using 5 g of dandelion leaves from Spain in 200 ml of water at 70°C during 2 hrs (Queralt I et al. 2005).
For the proposed posology – up to 10 g of dandelion leaves, 3 times daily as tea (British Herbal Pharmacopoeia 1976) – the daily intake up to 3114 mg of potassium could be possible. This intake represents about 66% of the recommended intake for healthy adolescents and adults, 103% for children 1 to 3 years of age, 82% for children 4 to 8 years of age, and 69% for children 9 to 13 years
of age, calculated for limits in Dietary Guidelines for Americans 2005. In the case of hyperkalemia, taking in account the relatively slow
3.4. Overall conclusions on
Reliable data on acute toxicity are only available for whole crude drug and some extracts. Oral administration of preparations from Taraxaci folium can be regarded as safe at traditionally used doses with the exception of patients with renal failure and/or diabetes, and/or heart failure. Toxicological data on dandelion are very limited, but neither the European traditional use nor known constituents suggest that there is a potential serious risk associated with the dandelion leaves use. Due to the lack of data on genotoxicity, mutagenicity, carcinogenicity, reproductive and developmental toxicity, a list entry for Taraxaci folium cannot be recommended.
4. Clinical Data
Clinical studies could not been found. Therefore, only the use as a traditional herbal medicinal product is proposed.
4.1. Clinical Pharmacology
No data are available.
4.1.1. Overview of pharmacodynamic data regarding the herbal substance(s)/preparation(s) including data on relevant constituents
No specific data are available.
4.1.2. Overview of pharmacokinetic data regarding the herbal substance(s)/preparation(s) including data on relevant constituents
No specific data are available.
4.2. Clinical Efficacy
No studies for clinical efficacy were found.
4.2.1. Dose response studies
There are no dose response studies available.
For information about posology and duration of use, see section 2.3.
4.2.2. Clinical studies (case studies and clinical trials)
No published data available.
4.2.3. Clinical studies in special populations (e.g. elderly and children)
No published data available.
4.3. Overall conclusions on clinical pharmacology and efficacy
In absence of clinical studies well established use cannot be supported.
The traditional use of Taraxacum officinale Weber ex Wigg., folium, as a herbal tea or hydroalcoholic extract, or juice for the increase of the amount of urine to achieve flushing of the urinary tract as an adjuvant in minor urinary complaints is documented in handbooks. The traditional use is supported by some pharmacological data.
5. Clinical Safety/Pharmacovigilance
5.1. Overview of toxicological/safety data from clinical trials in humans
No specific data are available.
5.2. Patient exposure
No data available.
5.3. Adverse events and serious adverse events and deaths
Anaphylaxis and pseudoallergic contact dermatitis is possible due sesquitepene lactones, e.g. taraxinic acid
Serious adverse events and deaths
No data available.
5.4. Laboratory findings
No data available.
5.5. Safety in special populations and situations
Intrinsic (including elderly and children)/extrinsic factors
No data available.
Theoretically, patients on lithium therapy who use herbal preparations with diuretic activity (e.g. dandelion) may experience dehydration and resulting lithium toxicity (Harkness R and Bratman S, 2003).
Use in pregnancy and lactation
No data available. In accordance with general medical practice, the product should not be used during pregnancy or lactation without medical advice.
No case of overdose has been documented.
No data available.
Withdrawal and rebound
No data available.
Effects on ability to drive or operate machinery or impairment of mental ability
No data available.
Occlusion of the bile ducts,
Hypersensitivity to the active substance(s) or to plants of the Asteraceae (Compositae) family.
5.6. Overall conclusions on clinical safety
Clinical safety data are almost lacking. However, up to now no serious side effects have been reported. Furthermore the chemical composition of dandelion does not give reasons for safety concerns, apart those mentioned in section 3.3.
As there is no information on reproductive and developmental toxicity, the use during pregnancy and lactation cannot be recommended.
Data on use in children or adolescents are not available.
6. Overall conclusions
The positive effects of Taraxaci folium for the diuresis stimulation (increase the amount of urine to achieve flushing of the urinary tract as an adjuvant in minor urinary complaints) have long been recognised empirically. There are no data available from clinical studies using herbal preparations containing Taraxaci folium.
Its medicinal use has been documented in relevant handbooks. Taraxaci folium preparations fulfil the requirements of Directive 2004/24 EC for use in traditional herbal medicinal products. Their use in the
The diuretic action of preparations from Taraxaci folium may be associated with high potassium content.
Reliable data on acute toxicity are only available for whole crude drug and some extracts. Oral administration of preparations from Taraxaci folium can be regarded as safe at traditionally used doses with the exception of patients with renal failure and/or diabetes, and/or heart failure. Toxicological data on dandelion are very limited, but neither the European traditional use nor known constituents suggest that there is a potential risk associated with the dandelion leaf use. Due to the lack of data on genotoxicity, mutagenicity, carcinogenicity, reproductive and developmental toxicity, a list entry for Taraxaci folium cannot be recommended.
In absence of clinical studies, a
The traditional use of Taraxacum officinale Weber ex Wigg., folium, as a herbal tea or hydroalcoholic extract, or juice for the increase of the amount of urine to achieve flushing of the urinary tract as an adjuvant in minor urinary complaints is sufficiently documented in handbooks.
Taraxaci folium preparations can be regarded as traditional herbal medicinal products.
There are no clinical safety data on extracts of Taraxaci folium. In the documentation of the traditional medicinal use within the European Union no serious adverse effects have been reported.
Due to lack of data, Taraxaci folium preparations cannot be recommended for children and adolescents below the age of 12 years, in pregnancy and lactation and must not be used in case of obstructions of bile ducts, cholangitis, liver diseases, gallstones, active peptic ulcer and any other biliary diseases.
Hypersensitivity to the Asteraceae sesquiterpene lactones or other active substances from Taraxaci folium is also regarded as a contraindication.
Preparations for the diuresis enhancement – ATC level C03.