Hypoglycaemic effect of Ipomoea batatas aqueous leaf and stem extract in normal and streptozotocin-induced hyperglycaemic rats

Abstract

Background: Among the Yoruba herbalists (South-west Nigeria), hot water infusion of the whole plant of Ipomoea batatas continues to be highly valued in the local management of diabetes because of its effectiveness in the control of blood glucose. Therefore, the present study investigates the blood glucose lowering effect of graded oral doses of the extract in normal and streptozotocin (STZ)-induced diabetic rats as a way of validating its folkloric use in the local management of diabetes mellitus. Materials and Methods: 100, 200 and 400 mg/kg/day of the aqueous whole plant extract of Ipomoea batatas (IB) were administered to normal and STZ-induced hyperglycemic rats as single, daily oral treatment for 14 days and their effects on the fasting blood glucose (FBG) was evaluated. In addition, the acute oral toxicity and preliminary phytochemical studies of IB were also conducted. Results: These showed that oral administration of IB for 14 days caused signifi cant dose related reductions (P<0.05, P<0.001) in FBG of both normal and STZinduced hyperglycemic rats. Oral treatment with 400 mg/kg/day IB also signifi cantly attenuated (P<0.05) body weight gain in the treated rats. The oral LD 50 for IB was estimated to be 12 g/kg while the phytochemical analysis of the extract showed the presence of alkaloids, fl avonoids, tannins, saponin, anthraquinones and reducing sugars in the extract. Conclusions: The data generated in this study validate the folkloric use of the hot infusion of the whole plant of IB in the local management of diabetes.