Antidiabetic mechanisms of Saponins of Momordica cymbalaria

Antidiabetic properties of Momordica cymbalaria is reported but not the mechanism of action. In the present study an attempt is made to study the possible mechanism of action. Saponins were separated from the Ethanolic extract, HPTLC fingerprinting was taken and used for the study. Diabetes was induced in 16 h fasted male Wistar rats by intraperitoneal injection of STZ (65 mg/kg).After 31 days treatment serum was analyzed for glucose, triglycerides, cholesterol, HDL-cholesterol, Insulin. The liver was analyzed for glycogen, mevalonate, HMG CoA, LPO, GSH, CAT and SOD. A portion of the pancreas was subjected to histopathology studies. In another batch of study Hyperinsulinemia was induced by feeding fructose rich diet for 15 days. After 15 days treatment serum was analyzed for glucose, triglycerides, cholesterol, and HDL-cholesterol; and Insulin. The liver was analyzed for HMG CoA and mevalonate. Alpha adrenergic antagonistic activity was studied on isolated rat’s aortic strip and on anconccygeous muscle. The concentration of the drug required to bring rightward shift of NA concentration curve with suppression of maxima was observed. Diabetic rats treated with saponins fractions of MC showed significant decrease in serum glucose, cholesterol, triglyceride level where as significant increase in serum insulin and liver glycogen level. HMG CoA reductase activity also showed significant increase. They also exhibited significant reduction in lipid peroxidation or MDA content in the heart and significantly increased the reduced glutathione content, catalase activity and SOD activity in the liver as compared to Streptozotocin control group Histopathological sections of the pancreatic islets in MC treated rats showed increase in the number of pancreatic cell islets which were similar to that of healthy pancreatic islets. Treating FRD fed rats with saponins of MC; the serum glucose, Cholesterol, triglyceride level significantly decreased and significantly increased the ratio of HMG CoA vs Mevalonate. Saponins of MC displayed significant rightward shift of NA concentration curve with suppression of maxima on isolated rat’s aortic strip and anconccygeous muscle preparation. The drug may act by reversing the atrophy of the pancreatic islets of β-cells, as a result may increase insulin secretion, increases hepatic glycogen level and attenuates Hyperinsulinemia. α-adrenergic blocking effect might contribute to insulin secretion and sensitizing effect