Isoflavones enhance plasma cholesterol-lowering activity of 7S protein in hypercholesterolemia hamsters
Previous study has shown that 7S-protein is the active ingredient responsible for plasma cholesterol-lowering activity of soybean. It is hypothesized that isoflavone in soybean could enhance blood cholesterol-lowering activity of 7S protein. Forty-eight hamsters were divided into six groups fed a non-cholesterol diet or one of five high-cholesterol diets containing 12.1% 7S protein with 0-15.62 mg/g isoflavones. Results showed that addition of isoflavones into diets dose-dependently enhanced plasma total cholesterol-lowering activity of 7S protein. Addition of isoflavone in 7S protein-based diets significantly reduced hepatic cholesterol accumulation by 12.6-26.1%, compared with HCD diet. Isoflavones could also facilitate excretion of neutral sterols in a dose-dependent manner. Supplementation of Isoflavones in diets favourably modulated mRNA expression and protein mass of HMG-CoA Reductase. It was concluded that the enhancing effect of isoflavones on blood cholesterol-lowering activity of 7S protein was mediated by inhibiting the cholesterol absorption and de novo cholesterol synthesis in hypercholesterolemia hamsters.