갈화에서 분리한 이소플라본의 항산화 및 세포보호효과

Antioxidative and Cytoprotective Effects of Isoflavones Isolated from Pueraria thunbergiana Flowers

Antioxidative and cytoprotective effects of tectorigenin and glycitein isolated from the Pueraria thunbergiana and its derivative, genistein, were determined. Among these three compounds, tectorigenin and glycitein bearing 6-methoxyl groups in both isoflavones showed significant free radical scavenging activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and xanthine/xanthine oxidase (XOD) generating superoxide anion radical. Tectorigenin only showed a slight inhibitory effect on XOD. We further studied the inhibitory effects of these isoflavones on the lipid peroxidation in rat liver microsomes induced by enzymatic and non-enzymatic methods. Each of them exhibited inhibitory effect on both ascorbic acid/Fe2+- and ADP/NADPH/Fe+3-induced lipid peroxidation. Moreover, tectorigenin exhibited the highest protection of hydrogen peroxide damage on HepG2 and Vero cells among the three isoflavones, in the cytoprotective assay. It was suggested that the pattern of antioxidative and cytoprotective effect of isoflavones could by crucially changed by the aromatic substitution of oxygen-containing groups.