Antidiabetic and Antioxidant Activities of Ethyl Acetate Extract of Terminalia superba in Streptozotocin-Nicotninamide Induced Type 2 Diabetic Rats

Abstract

The antidiabetic and antioxidant effect of ethyl acetate extract of Terminalia superba (combretaceae) was investigated in streptozotocin-nicotinamide induced type 2 diabetes. Diabetes was induced in adult male wistar rats by intraperitoneal injection of 110 mg/kg of nicotinamide, 15 min before an intravenous injection of 65 mg/kg of streptozotocin. The effects of the plant extract were evaluated on serum glucose, lipid profile, some parameters of oxidative stress, hepatic and renal function. The effects of plant extract on blood pressure were also monitored. Daily administration of the plant extract provoked a significant (P< 0.01) dose dependent reduction in serum glucose levels. At the end of treatment the percentages of reduction were 34.10% and 42.02% at the doses of 75 and 150 mg/kg respectively. Oral administration of the plant extract for 28 days showed a significant improvement in lipid profile and a significant reduction of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST). Treatment with the plant extract significantly provoked a reduction of aorta, liver and kidney malondialdehyde, and induced a significant improvement in reduced glutathione, superoxide dismutase activity when compared with diabetic control. Blood pressure measurement revealed that, at all doses (75 mg/kg and 150 mg/kg), the plant extract prevented (15.33% and 15.39% of reduction) the rise in mean blood pressure observed in diabetic control rats. These results suggest that ethyl acetate extract of T. superba lowers blood glucose and hyperlipidemia, prevents oxidative stress and reduces blood pressure in diabetic conditions, thus justify its traditional use for the management of diabetes and hypertension.

Keywords: Antidiabetic, antioxidant, streptozotocin-nicotinamide induced diabetes, Terminalia superba