Effects of buckwheat sprouts on plasma and hepatic parameters in type 2 diabetic db/db mice

We examined the effects of buckwheat sprouts (BS) (Fagopyrum esculentum Moench) on lipid and carbohydrate metabolism and on in vivo oxidative stress in type 2 diabetic mice. Mice (C57BL/KsJ-lepr(db)/lepr(db), db/db) were fed a diet containing 0%, 5%, or 10% BS based on AIN-93G for 21 d. Plasma parameters, such as total cholesterol, arteriosclerotic index, thiobarbituric acid reactive substances (TBARS), and the HbA1c concentration of whole blood in the diabetic BS-fed groups were lower than those in the diabetic control (AIN-93G) group. Concentrations of hepatic parameters, such as lipids, total cholesterol, triglyceride, and TBARS levels in BS-fed groups, were lower than those in the diabetic control group. Although gene expressions of the hepatic lipid regulation enzymes such as 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoAR) and cholesterol 7α-hydroxylase (CYP7A1) in diabetic BS-fed groups were higher than in the diabetic control group, the elevation of mRNA level of CYP7A1 was greater than that of HMG-CoAR. In addition, concentration of bile acids in feces was higher in the diabetic BS-fed groups than in the diabetic control group. These results suggest that BS have various in vivo activities in relation to antidiabetic effects in type 2 diabetic mice, especially for improvement in lipid metabolism. It was deduced that excretion of bile acids in feces by feeding the BS diet would contribute to the suppression of the cholesterol concentration in the plasma and liver tissues of mice.