Antioxidant activity and three phenolic compounds from the roots of Taraxacum gracilens Dahlst

Background and Aims: The genus Taraxacum is a member of the family Asteraceae. Taraxacum species are widely distributed in the warmer temperate zones of the Northern Hemisphere. The aim of this study was to evaluate the phenolic contents and antioxidant activity of the ethanol extract and its chloroform and ethyl acetate fractions from the roots of Taraxacum gracilens Dahlst. and isolate some of its phenolic compounds. Methods: The roots of T. gracilens Dahlst. werefirst macerated with EtOH and fractionated to obtain chloroform and ethyl acetate fractions, and then phenolic compounds were isolated by column chromatography. The polyphenolic contents and antioxidant activities of the fractions were evaluated by measuring their abilities to inhibit lipid peroxidation induced by Fe (3+) ascorbate, their reducing powers, and their hydrogen-donor activities. Results: Three phenolic compounds [vanillic acid (1), caffeic acid (2) and luteolin (3)] were isolated from the roots of T. gracilens Dahlst. The ethyl acetate fraction from the ethanol extract of T. gracilens Dahlst. roots showed the highest antioxidant activity due to its richest phenolic contents, whereas the ethanol extract containing the least phenolics was the weakest in activity. Conclusion: The fractions have potential to act as antioxidant agents. T. gracilens Dahlst. roots were investigated for the first time in literature data in terms of phenolic contents and antioxidant activity. Keywords: Taraxacum gracilens dahlst., Root, Phenolic compounds, Antioxidant activity