Tartary buckwheat sprout powder lowers plasma cholesterol level in rats

Abstract

We examined the effects of different types of buckwheat sprouts on the plasma cholesterol concentration, fecal steroid excretion and hepatic mRNA expression related to cholesterol metabolism in rats. Rats were fed a cholesterol-free diet with 5 g of Kitawasesoba common buckwheat sprout powder (KS)/100 g, 5 g of Hokkai T no. 8 tartary buckwheat sprout powder (HS-8)/100 g or 5 g of Hokkai T no. 9 tartary buckwheat sprout powder (HS-9)/100 g of diet for 4 wk. Control rats were fed a diet with α-cornstarch instead of sprout powder for 4 wk. There were no significant differences in food intake, body weight, liver weight or cecal contents among the groups. Plasma total cholesterol concentrations in the HS-8 and HS-9 groups were significantly lower than in the control group, whereas there was no significant difference between the KS and control groups. Fecal bile acid excretion and cecal short-chain fatty acid concentrations in the KS, HS-8 and HS-9 groups were significantly greater than in the control group. Furthermore, fecal matter excretion in the KS, HS-8 and HS-9 groups tended to be increased compared to the control group, with that in the HS-8 group being significantly higher than in the control group. Hepatic cholesterol 7α-hydroxylase mRNA expression in the KS, HS-8 and HS-9 groups and hepatic HMG-CoA reductase mRNA expression in the HS-9 group were significantly higher than in the control group. The results suggest that tartary buckwheat sprout powder has a serum cholesterol-lowering function by enhancing fecal bile acid excretion through increased fecal matter excretion or the upregulation of hepatic cholesterol 7α-hydroxylase mRNA expression in rats.