Acute toxicity and hypoglycemic properties of ethanolic root extract of Vernonia amygdalina (bitter leaf) in alloxan- induced diabetic rats

Diabetes mellitus is a group of metabolic disease characterized by chronic hyperglycemia due to defective insulin secretion, insulin action, or both, resulting to impaired carbohydrate, lipid, and protein metabolism. The qualitative analyses of Vernonia amygdalina root extract were carried out using standard methods. Acute toxicity of the extract was determined. Adult male albino rats were induced intraperitoneally with alloxan. The rats were grouped into six groups of five animals per group: Group A rats are not induced with alloxan, Group B animals serve as the negative control, Group C animals serve as positive control and were treated with glibenclaimide, Group D, E and F animals were treated with 200, 400 and 600 mg/kg body weight of ethanolic root extract of V. amygdalina respectively. The extracts were administered to the animals orally for 14 days. The animal’s blood sugar levels were assayed using blood glucose test strips and Accu-chek active glucometer. The lipid profiles and oxidative stress parameters were assayed using standard methods. The phytochemical analysis of Vernonia amygdalina root extract shows the presence of secondary metabolites like saponin, tannin, anthraquinone, reducing sugar, phenol, anthocyanine, steroid and terpenoid. The histopathological studies show that the extract is not toxic and safe for human consumption. The animals administered with 200, 400 and 600 mg/Kg B.W of extract showed significant decrease (P<0.05) in blood sugar level compared to the untreated animals. The decrease in the blood glucose level of the animals following the administration of the plant extract suggested that the plant extract possesses hypoglycemic effects in alloxan- induced diabetic rats. The extract of V. amygdalina produces hypolipidaemic effect and this is evident as there are significant decrease in plasma total cholesterol,triglycerides, low density lipoprotein-cholesterol and an increase in plasma high density lipoprotein-cholesterol in the treated groups compared to the untreated group. The extract significantly increases (P<0.005) superoxide dismutase, catalase, reduced glutathione and also reduces malondialdehyde values in the liver homogenate, an indication that the extract possess antioxidant properties.