Objective: To study the hypoglycemic effect and its action mechanism of water extract of Gymnema sylvestre fruit. Method: Acute toxicity was studied by using modified Karber's method. Diabetic mice and rats induced by alloxan were used as the models

and metformin was used as the positive control drug. In the experiment

glucose peroxidase method (GOD-POD) was used to determine the blood glucose in mice and rats

and observe the hypoglycemic effect of high

medium and low dose water extract of fruit of G. sylvestre. The superoxide dismutase (SOD) activity

total cholesterol

triglyceride

and glucose tolerance were detected in rats before and after treatment by using SOD activity kit

total cholesterol kit (COD-CE-PAP)

triglyceride kit (GPO-PAP) method

and GOD-POD method respectively; pathological state of pancreatic tissues before and after treatment was compared in hyperglycemic rats and mice

and then the hypoglycemic mechanism of water extract of fruit of G. sylvestre was explored. Result: The lethal concentration of 50%(LD50) of water extract was 66.65 g·kg-1

and as compared with normal group

blood glucose of the model group was decreased significantly (P<0.01)

and the water extract could decrease the blood glucose of the diabetic mice and rats induced by alloxan (P<0.01). As compared with the model group

various treatment groups had significantly different blood glucose (P<0.01)

improved the SOD activity

decreased triglyceride

improved pancreas and increased the amount of islets in rats

but it did not affect the glucose metabolism. Conclusion: The water extract of fruit of G. sylvestre had low toxicity and better hypoglycemic effect. Its mechanism is associated with the antioxidant capacity

regulation of the lipid metabolism and glucose metabolism

this paper can provide scientific basis for defining the hypoglycemic effect substance of fruit of G. sylvestre.