Taraxcum: a review.
Dandelions (Physiological aspects)
Materia medica, Vegetable (Health aspects)
Materia medica, Vegetable (Usage)
Plant extracts (Health aspects)
Plant extracts (Usage)
|Publication:||Name: Australian Journal of Medical Herbalism Publisher: National Herbalists Association of Australia Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2007 National Herbalists Association of Australia ISSN: 1033-8330|
|Issue:||Date: Spring, 2007 Source Volume: 19 Source Issue: 1|
|Geographic:||Geographic Scope: Australia Geographic Code: 8AUST Australia|
Schultz K, Carle R, Schieber A. 2006. Taraxacum--A review on its
phytochemical and pharmacological profile. J Ethnopharmacol 107;313-23.
The Taraxacum genus is a member of the daisy family (Asteraceae). Dandelion (Taraxacum off.) root and leaf have been used since antiquity in many cultures for the treatment of various ailments. The word Taraxacum derives from the Greek word 'taraxis' for inflammation and 'akeomai' for curative. Arabian physicians used the plant to treat liver and spleen aliments and Native Americans for kidney disease and dyspepsia. In Mexico and Turkey dandelion is used to aid in the control of diabetes, while in TCM the root is used to 'drain heat' in skin, urinary and febrile and upper respiratory tract diseases. Apart from therapeutic use dandelion leaves can be consumed in salads and the root can be used as a coffee substitutes.
German Commission E and European Scientific Cooperative for Phytotherapy (ESCOP) list the therapeutic indications of dandelion for restoration of the hepatic and biliary function, dyspepsia, loss of appetite and to support urinary secretion in conditions such as rheumatism and renal gravel. Aside from Commission E, ESCOP endorsement and global traditional use, no human clinical studies currently exist, which is surprising due to the wealth of empirical evidence.
Taraxacum species are rich in bitter principles due to the sesquiterpenes. Other constituents include various triterpenes and phytosterols, phenolic compounds, coumarins and flavonoids. Dandelion leaf is rich in potassium with levels of inulin ranging from 2% in the spring and 40% in autumn.
Dandelion is commonly prescribed by phytotherapists for choleretic, cholagogue, laxative, diuretic, anti-inflammatory, antirheumatic and hypoglycemic (Turkey and Mexico) activity. Taraxacum leaf is used over the root part to evoke diuresis due to its high potassium content, although animal studies have demonstrated conflicting results regarding diuretic activity. One study that did not show diuretic activity used the root and another negative study administered the preparation intraperitoneally. Choleretic activity has not been explored to the extent that Cynara spp. has been studied. A 40% increase in bile secretion occurred in rats after intraduodenal administration of a whole plant dandelion extract. Anti-inflammatory action has been demonstrated in a variety of in vitro and animal models. Inhibition of TNF-[alpha], interleukin-6, leukotriene B4, TPA-induced edema and carrageenan-induced oedema has been shown in mice. Antioxidant activity has also been demonstrated, dandelion extracts scavenging reactive oxygen species, hydroxyl radical species, cyclo-oxygenase-2, bacterial lipopoly-saccharide-activated mouse macrophage RAW264.7 cells.
Taraxacum spp. isolated constituents have shown in vitro anticarcinogenic activity. Taraxerol and taraxasterol exhibited strong inhibition of skin tumours. A dried aqueous extract of dandelion induced apoptosis in human hepatoma cell lines. Taraxinic acid has demonstrated significant cytotoxicity against human leukaemia derived H-60 cells. In a hot plate test 100 mg/kg of dry ethanolic dandelion extract administered intraperitoneally enhanced reaction time and reduced the writhing response. Anti-allergic activity was demonstrated by the sesquiterpene desacetylmatricarin via the attenuation of hexoaminidase, which occurs with histamine release when mast cells are activated.
Dandelion has demonstrated a hypoglycemic effect in a variety of animal and in vitro models. Administered to alloxan induced diabetic mice in a concentration of 20 mg/kg dandelion extract significantly reduced glucose and fructosamine levels. Dandelion root has demonstrated ADP induced platelet aggregation in vitro. Prebiotic activity has been shown after intestinal bacteria was incubated with an aqueous dandelion root extract. Growth of six beneficial intestinal bacterial strains occurred due to presence of oligofructans, Bifido adolesentis, Bifido bifidum, Bifido catenulatum, Bifido longum. Taraxacum spp. due to the absence of alkaloids have low toxicity, with a fluid herb and root extract showing LD50 of 28.8 and 36.6 g/kg body weight. Rabbits treated orally with whole dried dandelion plants at 3-6 g/kg body weight showed no visible signs of acute toxicity.
Comment: Taraxacum root and leaf has been and still is a commonly used hepatic in herbal medicine practice. It is therefore surprising and unfortunate that the only data presently existing are in vitro and animal studies. Human trials studying the diuretic action of the leaves and the hepatoprotective and choleretic action of the root would be relatively inexpensive and could potentially elevate the phytomedicine to the same clinical regard as St. Mary's thistle (Silybum marianum) and globe artichoke (Cynara scolymus).
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