Antidiabetic activity of cycloart-23-ene-3β, 25-diol (B2) isolated from Pongamia pinnata (L. Pierre) in streptozotocin-nicotinamide induced diabetic mice

The aim of the present investigation was to evaluate the antidiabetic activity of cycloart-23-ene-3 beta, 25-diol (called as B2) isolated from stem bark of Pongamia pinnata in streptozotocin-nicotinamide induced diabetic mice. Diabetes was induced in mice by injecting streptozotocin (200 mg/kg, i.p.)after 15 min nicotinamide (110 mg/kg, i.p.). The mice were divided into following groups; I - nondiabeteic. II - diabetic control, III - glybenclamide (10 mg/kg, p.o.), IV - B2 (1 mg/kg, p.o.) and V - B2 (3 mg/kg, p.o., only for acute study). Serum glucose was determined periodically. Body weight, food and water intake were recorded daily. Oral glucose tolerance test was performed on day 28. Biochemical and enzyme antioxidant parameters were determined. Histology of pancreas was performed. B2 and glybenclamide treatment reduced serum glucose in acute study. However in chronic study, increase in body weight and decrease in food and water intake was observed. Increased glucose utilization was observed in oral glucose tolerance test. Both glybenclamide and B2 increased serum and pancreatic insulin. Glycosylated haemoglobin, serum cholesterol, triglycerides, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, globulin, bilirubin, lactate dehydrogenase, urea and uric acid were decreased significantly after B2 treatment. B2 treatment decreased liver malondialdehyde but increased superoxidase dismutase and reduced glutathione. Histologically, focal necrosis was observed in the diabetic mouse pancreata but was less obvious in treated groups. The mechanism of B2 appears to be due to increased pancreatic insulin secretion and antioxidant activity. (C) 2010 Elsevier B.V. All rights reserved.