Antioxidant and antipromotional effects of the soybean isoflavone genistein.Author: Wei H et al. Publication: Proc Soc Exp Bio Med 1995 Jan; 208(1)124-130.
This research was done at the Department of Environmental Health Sciences, University of Alabama (Birmingham). The purpose of this study was to investigate the antioxidant and antipromotional effects of the soybean isoflavones. The test were done with HL-60 cells and the mouse skin tumorigenesis model.
The levels of hydrogen peroxide (H2O2), a strong oxidant, was measured in 12-O-tetradecanoylphorbol-13- acetate (TPA) activated HL-60 cells and superoxide anion generation by xanthine/xanthine oxidase.
Results of TPA test: of all tested isoflavones, genistein has the strongest antioxidant effect, followed by daidzein. Apigenin and biochanin A show little effect.
Results of oxidase test: genistein, apigenin and prunectin are equally potent in inhibiting O2- generation by xanthine/xanthine oxidase. Daidzein showed only moderate effect and biochanin A exhibiting no antioxidant effect. These results suggest that the antioxidant properties of isoflavones are structurally related.
Mice fed with 250 ppm genistein for 30 days showed increases activities of antioxidant enzymes in the skin and small intestine. In another study low levels of genistein significantly prolong tumor latency and decrease tumor multiplicity by approximately 50%.