Artemisia dracunculus L. (tarragon): A critical review of its traditional use, chemical composition, pharmacology and safety.

Abstract

Artemisia dracunculus L. (tarragon) has a long history of traditional use as a spice and natural remedy. Two well-described 'cultivars' of the species (Russian and French) are most widely used and differ in ploidy level, morphology and chemistry. Their most important groups of biologically active secondary metabolites are essential oils (0.15-3.1%), coumarins (> 1%), flavonoids, and phenolcarbonic acids. Diverse in vivo studies, particularly from Russian sources, highlight potential anti-inflammatory, hepatoprotective and antihyperglycaemic effects. However, pharmacological potential was mainly evaluated in rodents and only one study involved healthy men in a randomized double-blind trial. Despite concerns about toxic effects of two of its main constituents, estragole (up to 74%) and methyl eugenol (up to 35%), no acute toxicity or mutagenic activity has been reported at doses relevant for human consumption. Water extracts of A. dracunculus contain very low amounts of estragole and methyl eugenol and are therefore considered to pose a very limited risk. Overall, a stronger focus on clinical studies and precise taxonomic and phytochemical definition of the source material will be essential for future research efforts.