Oestrogenic potency of genistin and daidzin in mice.

The oestrogenic activity of genistin and daidzin was investigated in the B6D2F1 strain of mouse. Diethylstilboestrol and genistein were used as positive controls. The oestrogenic response to 1.5 mg genistin was equivalent to that of 1 mg genistein, giving a 1:1 molar relationship in oestrogenic activity between genistin and genistein. The oestrogenic response to 3.8 mg daidzin was equivalent to that of 1 mg genistein. Analysis of the blood obtained from the mice in this experiment failed to reveal any free genistein or daidzein in the plasma.