Antidiabetic Activities of Aqueous Stem Bark Extract of Strychnos henningsii Gilg in Streptozotocin-nicotinamide Type 2 Diabetic Rats

Strychnos henningsii Gilg is recommended among other remedies for the treatment of diabetes in traditional medicine of Southern Africa. The antidiabetic effect of oral administration of aqueous bark extract of the plant at 125, 250 and 500 mg/Kg body weight was investigated in diabetic rats induced with streptozotocin-nicotinamide for 15 days. The extract decreased the blood glucose level, feed and water intake as well as triacylglycerol at the three doses investigated while the best result was obtained at 250 mg/Kg. Similarly, the extract was able to lower the cholesterol level appreciably at 500 mg/Kg while the remaining doses did not have any significant effect as compared with diabetic untreated groups. In addition, the weight loss of diabetic-treated rats was markedly normalized at all doses. The glucose tolerance level of diabetic animals was effectively reduced to near normal level after 90 min of extract administration especially at the dose of 250 and 500 mg/Kg. The phytochemical screening of S. henningsii revealed the presence of flavonoids, tannins and saponins which have been reported to increase the insulin secretion. The results obtained from this study demonstrated that the aqueous extract of S. henningsii possess antihyperglycemic and antilipidemic properties and thus could prevent various complications of diabetes. Generally, this study has validated the traditional use of this plant for the treatment of diabetes mellitus.