Comparative study of the hypoglycemic effect of Azadirachta indica (Neem),Ocimum sanctum Tulsi) and Tinospora cordifolia (Chittamruthu) and their combination in diabetic rats

Abstract

The present study was undertaken to assess and compare the hypoglycemic effects of alcoholic extracts of Azadirachta indica and Ocimum sanctum leaves and Tinospora cordifolia vines and their combination at 200 mg/kg dose rate in alloxan diabetic rats and to compare their efficacy with standard oral hypoglycemic drug, glibenclamide. The experiment was conducted in forty eight alloxan induced diabetic rats of either sexes for a period of 37 days. Rats were divided into six groups of eight each. Group I was administered alcoholic extract of Azadirachta indica at 200mg/kg for 30 days from 7th day onwards, Group II received Ocimum sanctum alcoholic extract at the same dose rate and Group III was given Tinospora extract at 200 mg/kg. A combination of alcoholic extracts of Azadirachta, Ocimum and Tinospora was fed to Group IV at 200 mg/kg body weight. Group V received glibenclamide at 0.5 mg/animal/day for 30 days and Group VI served as diabetic control. Blood glucose level was estimated on zero day, 7th, 15th, 21st, 30th and 37th day. Body weight was taken at weekly intervals. Serum cholesterol, serum triglyceride and liver glycogen were estimated at 37th day of the experiment. All the treatment groups (I, II, III and IV) showed a gradual increase in body weight during the experimental period, but it was seen that the body weights never returned to their original weights before the commencement of the experiment. Among the treatment Groups I, II and III, Group I given Azadirachta extract had the maximum decrease in blood glucose level. Group IV which received a combination of the three drugs had a higher reduction compared to Group I, II and III. Results suggested a synergistic effect of the combination. However, the effect was comparatively lower than that of glibenclamide. Significant reduction in serum cholesterol level was seen in Group I, II and III. Highest cholesterol level was seen in Group II and the lowest serum cholesterol level was seen in Group IV. Serum triglyceride level was highest in Group II and III. Group I had a comparatively lower serum triglyceride level. Lowest triglyceride level was shown by Group IV treated with combination. Treatment with all the three drugs resulted in no significant change in the liver glycogen levels. Combination treatment also failed to produce any significant alteration in the reduced liver glycogen levels. Group I, II and III had a liver glycogen levels comparable to that of the control Group VI. From the study, it can be concluded that among the three drugs, Azadirachta has the highest hypoglycemic and hypolipidemic effect. The combination treatment produced a comparatively higher effect than that of the three drugs, suggesting a synergistic action. However, the effects of the three drugs and their combination are less when compared to that of glibenclamide and the mechanism of action of the three plants are different from that of glibenclamide.