Growth inhibition of human endothelial cells by the phyto-oestrogen biochanin A, a metabolite of genistein.

This study examined the growth regulatory effects of a phyto-oestrogen, biochanin A, on a transformed human endothelial cell line ECV304 in vitro. Biochanin A was found to inhibit cell proliferation in a dose-dependent fashion and this effect was influenced by the concentration of serum present in the culture medium. In the absence of serum, the calculated IC50 of biochanin A was 0.18 +/- 0.1 microm compared to an IC50 of m at 10% serum. At low cell density, the growth inhibitory effects of biochanin A were more evident than at high cell density. Co-administration of a synthetic oestrogen diethylstilboestrol with biochanin A did not suppress the growth regulatory effects of biochanin A treatment. We conclude that biochanin A inhibits the cell proliferation of human endothelial cells at concentrations that are physiologically achievable in vivo and that this effect may play an important role in the cancer-preventing activity of the phyto-oestrogens.