Effects of Black Rice Containing Anthocyanins on Plasma and Hepatic Parameters in Type 2 Diabetic db/db Mice

We examined the effects of black rice (BR) (Oryza sativa L.) grains and an anthocyanin (AC) extract of the grains on lipid and carbohydrate metabolism and in vivo oxidative stress in type 2 diabetic mice. Mice (C57BL/KsJ-lepr(db)/lepra(db), db/db) were fed an AIN-93G based diet containing 20% (w/w) boiled BR grains or the AC extract (0.015% or 0.03%, w/w) for 21 days. TBARS levels in the liver tissues of the BR-and AC-diet groups were lower than those of the diabetic control (DC) group. Concentrations of other parameters, such as plasma arteriosclerotic index, hepatic lipids, and total cholesterol in liver tissues in the AC-diet fed group were lower than those in the DC group, and tended to be lower in the BR-diet group than in the DC group. Fecal concentrations of bile acids and cholesterol were higher in the BR-and AC-diet fed groups than in the DC group. These results suggest that compounds in the AC extract contribute to the improvement of lipid metabolism and suppression of in vivo oxidative stress by ingestion of BR grains.