Isoflavones inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase in vitro.

Isoflavones identified as inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in soybean paste were assayed using the catalytic portion of Syrian hamster HMG-CoA reductase, and the kinetic values were measured using HMG-CoA and NADPH. The inhibition of HMG-CoA reductase by these inhibitors was competitive with HMG-CoA and noncompetitive with NADPH. Ki values for genistein, daidzein, and glycitein were 27.7, 49.5, and 94.7 microM, respectively.