comparative study of effects of gymnema sylvestre extract, tolbutamide and metformin on blood lactic acid levels of normoglycaemic and hyperglycemic rabbits

ABSTRACT

To study the possible mechanism of hypoglycaemic action of Gymnema sylvestre, the the effects of the administration of its watery extract in doses of 50, 100, 150 and 200 mg/kg body weight, on blood lactic acid levels of normoglycaemic and hyperglycaemic rabbits were studied blood lactic acid levels were estimated before and after two, four and six hours of administration. The results were compared with the effects produced by tolbutamide [250 and 500 M/ kg] and metformin [50 and 100 mg/kg]. Gymnema sylvestre and tolbutamide did not produce any significant effect on blood lactic, 1-7L -ls. Metformin, however, produced a significant rise [P < 0.05] in blood lactic acid levels -nuglycaemic and hyperglycaemic rabbits. The obseruation that Gymnema sylvestre did not produce any significant effect on blood lactic acid levels suggests that its mechanism of action is different from that of oral comic agents of biguanide group like metformin. Thus it may be indirectly -red that hypoglycaemic action of Gymnema sylvestre is due to a mechanism of action similar to that sulfonylureas like tolbutamide, which involves release of insulin from pancreatic beta cells of islets of Langerhan. However further controlled studies including S of blood insulin levels are needed to arrive at any definite conclusion: