EVALUATION OF HYPOGLYCEMIC EFFECT AND PHYTOCHEMICAL CONSTITUENTS OF VERNONIA AMYGDALIN DEL. FAM. ASTERACEAE

Purpose: Leaf of Vernonia amygdalin Del Fam. Asteraceae has been shown to have hypoglycemic activity. This work was designed to identify the secondary metabolites present in the plant leaf, test their lethality, and then determine the best solvent system for their extraction. Methodology: One kilogram of crushed leaves of the plant Vernonia amygdalin was extracted with 5.0 L of methanol using Sohlex extractor. The solvent systems used in thin layer chromatography were petroleum ether, N-hexane, diethyl ether, dichloromethane and methanol. The dichloromethane/Methanol fraction which showed the highest TLC separation was fractionated in a column packed with silica gel G254 and eluted gradiently at various ratio. Fractions that showed similar TLC characteristics on analysis were subjected to antidiabetic studies using Wister albino rats. LD50 was determined using Lorke,s method. Alloxan was used for hyperglycemic induction. Glibenclamide was used as the standard drug 1. Five groups of five rats per group were used. Blood glucose levels were determined using Accu check glucometer. Data was analyzed using analysis of variance with a randomized design at p<0.05. Result: Preliminary phytochemical analysis showed the plant contains alkaloids, saponins, flavonoids, terpenes, steroids. The LD50 of the extract is above 5000 mg/kg. The administration of Alloxan increased significantly p<0.05 the blood glucose level of rats. The crude methanol extract at the doses of 100 mg/kg and 200mg/kg gave percentage reductions of 60.53% and 53.08% of hyperglycemia within 24 h. Gglibenclamide gave 51.8% reduction. Methylene: methanol extract (7:3) gave the best separation. Conclusion: The findings showed that the extracts of Vernonia amygdalin have hypoglycemic activity.