Pteleopsis suberosa Engl. and Diels (Combretaceae) aqueous stem bark extract extenuates oxidative damage in streptozotocin-induced diabetic Wistar rats

Context: Pteleopsis suberosa Engl. and Diels (Combretaceae) is an ethnomedicinally valued deciduous shrub with significant therapeutic application against diabetes in West Africa. Aims: This study evaluated the hypoglycaemic and antioxidant activity of its aqueous stem bark extract (PSAE) over a 15-day experimental period in streptozotocin (STZ)-challenged diabetic rats. Methods and Material: STZ-induced diabetic rats were administered 50, 100 and 200 mg/kg body weight of the extract once daily and the blood glucose levels were monitored for 15 days. The bioactive constituents of PSAE were analyzed using Gas Chromatography- Mass Spectrometry (GC-MS) technique. Results: Treatment with PSAE markedly (p< 0.05) ameliorated the concentrations of blood glucose and improved the lipid metabolism imbalance in the diabetic animals. Also, while PSAE significantly (p<0.05) improved glycogen and glutathione (reduced) levels as well as glucose-6-phosphate dehydrogenase, superoxide dismutase and catalase activities, the concentrations of glucose and malondialdehyde coupled with the activity of α-amylase were significantly reduced in the liver of PSAE-administered diabetic animals when compared with those of the normal control and untreated diabetic groups. The observed improvements could be associated with the phytoconstituents of PSAE as evident from the results of the GC-MS analysis. Put together, the elicited effects compared favorably well with metformin (a standard hypoglycemic drug) and are suggestive of antidiabetic and antioxidant capabilities of the extract. Conclusion: The scope of the data presented in this study indicates that the extract ameliorated streptozotocin-induced diabetes in rats and it is suggested to be mediated via antioxidant and concerted blood glucose lowering actions.