Anti-diabetic potentials of stem-bark extracts of Terminalia avicennioides on alloxan-induced diabetic rats

Abstract

This study evaluated the extracts of Terminalia avicennioides stem-bark for their effect on alloxan-induced diabetes mellitus in male wistar rats. The powdered stembark of the plant was extracted with 70% methanol to yield crude methanol extract (CME). The CME was dissolved in distilled water to obtain the aqueous methanol (AME), then partitioned using ethyl acetate and hexane to obtain ethyl acetate (EAE) and hexane (HEX) extracts respectively. Fifty five alloxan induced diabetic rats were randomly divided into 11 groups of five rats each. Rats in groups1 and 2 received distilled water (DW) and 1% Tween 80 (TW80) at 5 ml/kg, respectively. Rats in group 3 received glibenclamide (GLB) 10 mg/kg. Rats in groups 4, 5, 6 and 7 were administered with 100 mg/kg of CME, AME, EAE and HEX,  respectively. Similarly, rats in groups 8, 9, 10 and 11 were given the extracts at 200 mg/kg, respectively. In addition, three normoglycaemic rats were used as non-diabetic non-treated control (group 12). All treatments and diabetic inductions were done intraperitoneally. Treatments started 72 hours after induction of diabetes which served as day 1, then on day 4, 7, 14 and 21. Blood glucose level in all the rats was monitored weekly for three weeks. All animals were sacrificed by jugular venipuncture and serum levels of total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL) and triglycerides (TGL) were determined. The extracts significantly (p<0.05) decreased the levels of blood glucose, serum total cholesterol, serum triglyceride and serum low density lipoprotein in diabetic rats when compared with the negative controls. However, HDL level was significantly (p<0.05) increased in the HEX, EAE and CME (100 mg/kg) treated rats. In conclusion, the extracts exhibited an anti-hyperglycaemic and anti-hyper lipidaemic effect which validates the use of the plant in traditional treatment of diabetes mellitus.

Keywords: Alloxan, anti-diabetic, extracts, rats, Terminalia avicennioides