Recent concerns about the potential carcinogenicity of estragole and methyleugenol led a number of regulatory bodies to call for restrictions on the use of herbs that contain these constituents. A number of medicinal plants produce essential oils that contain estragole and methyleugenol, including Artemisia dracunculus L. (tarragon). Previous studies have proven the antidiabetic properties of tarragon. In order to address the safety concerns of estragole containing tarragon extracts, an extraction procedure was developed to minimize the estragole and methyleugenol content in tarragon extracts and the ethanol versus aqueous extracts from two Artemisia dracunculus cultivars (French and Russian tarragon) were tested for blood glucose lowering effects in rats. It could be demonstrated that aqueous extracts of both Artemisia cultivars did not contain detectable amounts of estragole and methyleugenol, whereas ethanol extracts (60% v/v) of the French cultivar contained higher levels of the aforementioned compounds than those of the Russian cultivar. Further testing revealed that Russian tarragon lowered blood glucose levels in rats after glucose challenge, with the ethanol extract being as active as the aqueous extract. The results suggest that by using adequate production procedures the amount of potentially harmful compounds in extracts can be limited without affecting the overall pharmacological activities of these preparations.
Copyright © 2011 John Wiley & Sons, Ltd.