Dandelion: Background. Actions

2010

Historical Note

Dandelion grows throughout the world as a weed and has a long history of medicinal and culinary use. Dandelion leaves are added to salads, providing a good source of minerals, and the roasted root is used as a coffee substitute. Dandelion leaves are traditionally used as a diuretic, and the root is used as a liver tonic.

Other Names

Blowball, cankerwort, common dandelion, lion’s tooth, priest’s crown, puff ball, swine snout, taraxacum, wild endive, white endive

Botanical Name / Family

Taraxacum officinale; synonyms: Leontodon taraxacum, Taraxacum vulgare (family Compositae [Asteraceae])

Plant Parts Used

Leaf and root

Chemical Components

Dandelion leaf and root contain slightly different constituents.

Overall, dandelion is a rich source of minerals, particularly potassium, as well as iron, magnesium, zinc, potassium, manganese, copper, choline, selenium, calcium, boron and silicon, and a rich source of vitamins A, C, D and B complex (US Department of Agriculture 2003). The relatively high protein, fibre and linoleic acid content of dandelion leaves has led to suggestions that dandelion is a nutritious and underutilised food source. Dandelion’s constituents also include triterpenes, flavonoid glycosides and various phenolic acids, as well as phytosterols, sugars and mucilage. The many phenolic acids and flavonoids include chicoric acid (dicaffeoyltartaric acid) and quercetin glycosides.

Main Actions

DIURETIC

Dandelion leaf has been found to have a greater diuretic effect than the roots, with activity comparable to that of frusemide, without causing potassium loss because of the leaves’ high potassium content. A study using an infusion of dandelion root found that dandelion did not significantly increase diuresis in rats, and no secondary metabolites showing major diuretic activity were found.

CHOLERETIC

The bitter constituents in dandelion root are believed to be responsible for increasing bile production and flow, as well as contributing to the root’s mild laxative effects.

HEPATIC ENZYME INDUCTION

In vivo studies have demonstrated decreased activity of CYP1A2 and CYP2E enzymes and dramatic increases in levels of the phase II detoxifying enzyme UDP-glucuronosyl transferase in liver microsomes of rats receiving dandelion tea. The same study found that dandelion tea had no effect on the activities of CYP2D and CYP3A.

ANTI-INFLAMMATORY AND ANTIOXIDANT ACTIVITY

Dandelion extract was shown to exhibit a mild analgesic and anti-inflammatory effect in mice, and an aqueous dandelion extract was found to prevent diabetic complications due to lipid peroxidation and free radicals in diabetic rats. Dandelion extract has also been found to have a protective effect against CCK octapeptide-induced acute pancreatitis in rats and dandelion flower extract demonstrated marked antioxidant activity that has been attributed to its phenolic content, with suppression of reactive oxygen species and nitric oxide. Extracts of dandelion flowers, roots and stem have been found to have significant OH-radical scavenging activity.

Other Actions

There is preliminary scientific evidence from animal and in vitro studies that suggests the roots of Taraxacum japonicum may have a cancer preventative effect. The extract has been shown to induce cytotoxicity through TNF-alpha and IL-1 -alpha secretion in vitro.

Traditionally, dandelion root is understood to have laxative activity and to stimulate digestion, whereas dandelion leaf has antirheumatic effects. Dandelion root infusion, which contains oligofructans, has been found to stimulate the growth of multiple strains of bifidobacteria, suggesting its use as a probiotic.

Dandelion may have antidiabetic actions, because ethanolic extracts of whole dandelion exhibited insulin secretagogue activity and dandelion in conjunction with various other herbal extracts has been shown to have an antihyperglycaemic effect in mice.