Herb-Drug Interactions: Dandelion

Taraxacum officinale Weber (Asteraceae)

Synonym(s) and related species

Lion’s tooth, Taraxacum.

Leontodon taraxacum L., Taraxacum densleonis Desf., Taraxacum palustre (Lyons) Lam & DC.

Taraxacum mongolicum Hand.-Mazz. is used in Chinese medicine.

Constituents

The root and leaf of dandelion contain sesquiterpene lactones including: taraxinic acid, dihydrotaraxinic acid, taraxacoside, taraxacolide and others; caffeic, chlorogenic and cichoric acids; the natural coumarins cichoriin and aesculin; and flavonoids based on luteolin. The phytosterols sitosterol, stigmas terol, taraxasterol and homotaraxasterol, the triterpenes beta-amyrin, taraxol and taraxerol, carotenoids, and vitamin A are also found.

Use and indications

Dandelion has been widely used as a diuretic, and also for its purported laxative, anti-inflammatory, choleretic (to increase bile secretion) and blood-glucose-lowering activity. Some of these activities have been demonstrated in some, but not all, animal studies, and no human studies appear to have been published. Dandelion has been used as a foodstuff (the leaf in salads, and the ground root as a coffee substitute). A prebiotic effect has been suggested for the root.

Pharmacokinetics

In a study in rats pre-treated for 4 weeks with a dandelion tea solution 2%, the solution inhibited the cytochrome P450 isoenzymes CYP1A2 and CYP2E by 85% and 52%, respectively, when compared with a control group, but did not change CYP2D and CYP3A activity. An increase in UDP-glucuronyl transferase activity of 244% was also reported in the rats given dandelion tea. The findings of animal studies cannot be directly extrapolated to humans, but positive findings such as these suggest that clinical studies are required. For information on the pharmacokinetics of individual flavonoids present in dandelion, see under flavonoids.

Interactions overview

No interactions specific to dandelion, although there is limited evidence from animals that Taraxacum mongolicum (the species used in Chinese medicine) might alter the absorption of ciprofloxacin. For information on the interactions of individual flavonoids present in dandelion, see under flavonoids.

Dandelion + Ciprofloxacin

The interaction between Taraxacum mongoUcum and ciprofloxacin is based on experimental evidence only.

Clinical evidence

No interactions found.

Experimental evidence

In a study in rats, an aqueous extract of Taraxacum mongolicum (2 g crude drug/kg) significantly reduced the maximum concentration of a single 20-mg/kg oral dose of ciprofloxacin by 73% when compared with administration of oral ciprofloxacin alone. The overall tissue distribution and half-life were also increased, although the AUC was not different. The Taraxacum mongolicum extract used was analysed and found to have a high concentration of magnesium, calcium and iron.

Mechanism

Cations such as magnesium, calcium and iron are known to chelate with ciprofloxacin and modestly reduce its overall absorption. However, in this study, the overall absorption of ciprofloxacin was unchanged. The reason for the reduced maximum level and prolonged elimination half-life is uncertain.

Importance and management

The general significance of this animal study is unclear, especially as the overall absorption of ciprofloxacin did not appear to be affected. Further study is required to discover if, and under what circumstances, dandelion might interact with ciprofloxacin in clinical use. Also, study is needed to see whether the effects of the dandelion species used in this study (Taraxacum mongolicum) apply to Taraxacum officinalis.

Dandelion + Food

No interactions found.

Dandelion + Herbal medicines

No interactions found.