The effect of extract of bitter leaf (Vernonia amygdalina) on blood glucose levels of diabetic rats

Abstract

Twenty-four (24) adult albino Wistar rats (twelve males and twelve females) were used for the study. The animals were divided into six groups of four rats in each. Proximate analysis was carried out on the plant sample with the following results: crude protein 22.45 ± 0.01%; crude fat (3.45 ± 0.0%); crude fiber (16.0 ± 0.0%) and Ash (9.95 ± 0.2%). Quantitative phytochemical analysis revealed the presence of flavonoids (0.85 ± 0.11 mg), tannins (0.37 ± 0.2 mg), saponins (2.2 ± 0.0 mg), polyphenol (0.35 ± 0.11 mg), alkaloids (2.13 ± 0.10 mg) and HCN (12.25 ± 0.10 mg). Some of the vitamins analyzed included: Vitamin A 345.50 ± 0.0 IU), Vitamin C (228.40 ± 0.0 mg), Vitamin E (37.30 ± 0.01 mg), Vit.B1 (1.0 ± 0.00 mg), Vit.B2 (3.10 ± 0.00 mg), Fe (11.0 ± 0.0 mg) and Niacin (0.41 ± 0.0 mg) respectively. Hyperglycemia was induced in the rats using alloxan. The plant extract of Vernonia amygdalina (bitter leaf) was administered to the rats orally at concentrations of 2%, 4%, 6%, 8% and 10% before meals for 5, 10 and 15 days respectively after which, blood samples were collected from the animals and analyzed for glucose levels using enzymatic methods. There was a remarkable decrease in blood glucose level from the mean value of 4.44 ± 0.2 to 1.66 ± 0.2 mmol/L. The decrease in the blood glucose level of the rats following the administration of the plant extract suggests that the plant extract possesses anti-diabetic, anti-hyperglycemic and hypoglycemic effects on alloxan induced diabetic rats. The presence of phytochemicals, vitamins and other nutrients such as proteins, lipids, carbohydrates, ash and other
components in the extract must have acted synergistically to potentiate the anti-diabetic role of the plant extract.

Keywords: Diabetes mellitus, hyperglycemia, diabetic rats, Vernonia amygdalina.