Type 2 antidiabetic activity of bergenin from the roots of Caesalpinia digyna Rottler

Abstract

Bergenin, a major constituent of Caesalpinia digyna Rottler (Leguminosae) was isolated from its roots and was characterized by comparing its melting point and spectroscopic data (IR, 1H, 13C, Mass Spectra) with standard bergenin. Isolated bergenin was then evaluated for antidiabetic (Type 2) activity in streptozotocin (STZ)-nicotinamide induced diabetic rats. Bergenin was administered at doses of 2.5, 5, and 10 mg/kg; p.o. to normal rats which were subjected to oral glucose tolerance test (OGTT). Bergenin at same dose level was given to diabetic rats and fasting blood glucose level was estimated on 0th, 7th and 14th day of treatment while plasma lipids, antioxidant enzymes and liver glycogen level in diabetic rats were estimated on 14th day of treatment followed by histopathological studies of pancreas. Bergenin at 10 mg/kg; p.o. was found to reduce blood glucose level significantly in OGTT (P < 0.01) while it showed a significant reduction in fasting blood glucose level in diabetic rats at same dose level only on 14th day of treatment. Bergenin in all dose levels reversed plasma lipid (reduced elevated TC, LDL-C and increased HDL-C level) profile to normal values except TG. However, bergenin showed no significant effect on liver glycogen at all dose level. The decrease in lipid peroxides and increase in superoxide dismutase (SOD) and catalase (CAT) in liver illustrated the antioxidant potential of bergenin. Histopathological studies demonstrated the regenerative effect of bergenin on pancreatic β cells. Hence, bergenin isolated from C. digyna possesses significant antidiabetic, hypolipidemic and antioxidant activity in Type 2 diabetic rats.