Hypoglycaemic effect of Coccinia indica (ivy gourd) leaves and its interaction with glibenclamide in diabetic rats

Abstract

The present study was undertaken to assess the hypoglycemic, hypolipidemic, antioxidant effect, interactive effects with glibenclamide and toxicity of ethanolic extract of Coccinia indica leaves. The experiment was conducted in seven groups of eight adult Sprague-Dawley rats each. Group I served as the normal control. All the groups except normal control were made diabetic by subcutaneous injection of alloxan at the dose rate of 130 mg/kg body weight and group II was kept as diabetic control. The groups III and IV were administered with the extract of C. indica at the dose rate of 200 mg/kg and glibenclamide at the dose rate of 0.25 mg/kg respectively for 45 days. The groups V, VI and VII were administered with a combination of C. indica at the dose rate of 100, 150 and 200 mg/kg respectively with glibenclamide at the dose rate of 0.125 mg/kg body weight for 45 days. Blood glucose, serum cholesterol and serum triglyceride and body weight were noted on day zero, 16th, 30th, 45th and 60th day and liver glycogen on 60th day. The antioxidant effect was assessed by estimation of reduced glutathione and lipid peroxides in pancreas and liver. Representative samples of pancreas were also subjected to histopathological examination. The diabetic control showed significant increase in the level of blood glucose, serum cholesterol and serum triglyceride level and also a significant reduction in body weight. All the other groups showed a gradual increase in body weight after 30 days of treatment. The groups III and IV restored the blood glucose levels after 45 days. The serum cholesterol, serum triglyceride, reduced glutathione and lipid peroxide levels in pancreas and liver were also restored indicating the hypolipidemic and antioxidant effect of the treatments. The groups V, VI and VII, in which the combinations of C. indica with glibenclamide were used, regained the blood glucose levels in 45 days of treatment. Group VII showed most marked effect and is found to be better than group III. The combination treatments produced a marked reduction in serum cholesterol and triglyceride levels and there was restoration of lipid peroxides and reduced glutathione in pancreas and liver. The ethanolic extract of C. indica leaves were screened for acute oral toxicity and sub acute toxicity. The administration of the extract upto 2000 mg/kg body weight (OECD guidelines 423) did not show any acute oral toxicity in mice. The sub acute toxicity studies conducted in wistar rats, did not show any toxic symptoms like mortality, change in biochemical, hematological parameters. The results revealed that C. indica did not possess any sub acute toxicity. These toxicity studies indicated the safety of ethanolic extract of C. indica as a drug in the treatment of diabetes. From the study it can be concluded that C. indica at the dose of 200 mg/kg body weight produced better hypoglycemic effect when compared with glibenclamide at the dose rate of 0.25 mg/kg body weight. Further the combination of C. indica ( 200 mg/kg ) with glibenclamide (0.125 mg/kg) showed a more effective hypoglycemic, hypolipidemic and antioxidant effect than C. indica or glibenclamide alone and the combination can be safely used in the treatment of diabetes.