Inhibitory effects of isoflavones on lipid peroxidation by reactive oxygenspecies

Possible inhibitory effects were investigated for four isoflavones, biochan in A, daidzein, formononetin and genistein on lipid peroxidation by reactiv e oxygen species. Biochanin A, formononetin and genistein inhibited lecithi n peroxidation which was induced by hydroxy radical generation, by interact ion of haemoglobin and hydrogen peroxide. Daidzein and formononetin inhibit ed lecithin peroxidation which was induced by superoxide anion generation b y xanthine-xanthine oxidase. These results demonstrated that the difference s in antioxidant activities of isoflavones are dependent on the relation be tween their chemical structures and reactive oxygen species. Copyright (C) 1999 John Whey & Sons, Ltd.