Quantification of genistein and daidzein in two endemic Genista species and their antioxidant activity

Abstract

In the current research, the total and free genistein and daidzein contents were determined in two endemic Genista species (G. sandrasica and G. vuralii) by an HPLC method. The highest amount of total genistein and total daidzein was found in G. sandrasica, 0.582 % and 0.113 %, respectively, whereas only the free daidzein content of G. sandrasica was higher than that of G. vuralii. The antioxidant activity of the crude methanol and hydrolyzed extracts of these species was evaluated by three in vitro methods; namely DPPH free radical scavenging, ferrous ionchelating and ferric-reducing antioxidant power (FRAP) tests at 0.25, 0.50, and 1.0 mg ml. The hydrolyzed extracts of both species displayed greater antioxidant activity than the crude methanol extracts in all tests. Total phenol and flavonoid contents in the extracts were determined via the Folin-Ciocalteau and AlCl3 reagents, respectively. G. vuralii was richer in terms of total phenol and flavonoid contents compared to G. sandrasica.