The protective effects of Olive leaf extract on Type 2 diabetes, the expression of liver superoxide dismutase and total antioxidant capacity of plasma in rats

Olive leaf has medicinal benefits in type 2 diabetes. the aim of this cross-sectional study was to evaluate the effects of the olive leaf extract on the prevention of type 2 diabetes induced by streptozotocin and nicotinamide, assessment of the expression of liver superoxide dismutase enzyme gene and total antioxidant capacity of plasma in rats. in this study 28 healthy, mature, sprague-dawely male rats with the initial weight of 250 ± 50 g were divided into 4 equal groups (group 1: healthy control; group 2: healthy trial; group 3: diabetic control; group 4: diabetic trial). fasting blood glucose in all rats was measured every week with the glucose oxidase method. at the end of our study, the animals were sacrificed and blood and liver were collected and all needed parameters were measured. fasting blood glucose was not significantly differente in the group 4 (439±47mg/dl) and group 3 (445±33 mg/dl), but with group 1 (85±11 mg/dl) significant difference was observed. there was no significant difference between total antioxidant activity and nitric oxide metabolites in groups but the expression of superoxide dismutase gene was significantly increased in group 2 and group 3 (p<0.05). histopathological results of the liver in group 4 showed macrophage accumulation, mild inflammation, apoptosis in comparison with other groups. the extract of olive leaf with a dosage of 100 mg/kg did not reduce blood glucose in diabetic rats. therefore, traditional methods used to treat diabetes type 1 and 2 do not only prevent but also diminish the ability to reduce blood sugar and can also cause damage to hepatocytes and other complications.