Evaluation of antihyperglycaemic and antihyperlipidemic activity of Citrus sinensis peel extract on streptozotocin-induced diabetic rats

The present study was aimed to evaluate the antihyperglycaemic and antihyperlipidemic activity potential of Citrus sinensis ethanolic peel extract in normal and streptozotocin (STZ)-induced diabetic rats. The dose-dependent effects of 28-day oral treatment with ethanolic peel extract (250 and 500 mg/kg) from the plant of C. sinensis on blood glucose, glycosylated haemoglobin (HbA(1)c), plasma insulin, carbohydrate-metabolizing enzymes (hexokinase, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, glycogen phosphorylase), glycogen levels and lipid levels were determined after oral administration of a dose of C. sinensis (250 and 500 mg/kg body weight) in diabetic groups. A significant decrease in blood glucose, glycosylated haemoglobin and lipid levels was observed in diabetic rats treated with C. sinensis. The activities of carbohydrate-metabolizing enzymes such as hexokinase were significantly increased whereas glucose-6-phosphatase was significantly decreased by the administration of C. sinensis in diabetic rats. A two-fold increase in insulin levels was observed, suggesting that the peel extract has an insulin secretory activity. The findings suggest that C. sinensis peel extract has potent antidiabetic activity in STZ-induced diabetic rats.