Effects of group B soyasaponins and soyasapogenol B on cholesterol levels

Elevated blood cholesterol levels are associated with the development of heart disease. Soyasaponins have been suggested as a factor capable of decreasing plasma lipid concentrations. Soyasaponins are naturally occurring triterpenoids found in soybeans, and their sugars are cleaved from soyasaponins in the digestive tract leaving the aglycone form - soyasapogenol B. The objectives of this study are to determine cholesterol-lowering efficacy and bioavailability of soyasapogenol B and group B soyasaponins. Forty-eight hamsters were assigned to one of four dietary treatment groups and fed for 4 weeks; 1) low fat control (LFC), 2) high fat control (HFC), 3) high fat diet with soyasapogenol B (SPG, 0.5 mmol/kg diet), and 4) high fat diet with group B soyasaponins (SSP, 1.5 mmol/kg diet). Compared to the HFC, SSP and SPG treatments were shown to decrease total cholesterol and triglyceride cholesterol levels, but the decrease was not significant. Fecal bile acid excretion was also not significantly different among dietary groups. SPG and SSP groups showed increased fecal neutral sterol excretion compared to the HFC, but only the SSP group was significantly greater (P<0.05). Hamsters in the SPG group showed a significantly greater bioavailability than the SSP group (P<0.05).