Fatty Acid Alkyl Esters from Vernonia amygdalina Leaf Extract as Potent Antibacterial Agents

Abstract

Isolation and identification of some medicinally active compounds from the crude extract of Vernonia amygdalina leaf was carried out. Phytochemicals in the crude ethanolic extract from the leaf of this plant were subjected to polarity based separation using column chromatographic technique. The purity of the eluates obtained was determined using Thin Layer chromatography. Microbial activities of the five pure eluates were tested against some randomly selected bacteria (Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Shigella sp. and Streptococcus pyogenes) and fungi (Aspergillus flavus, Aspergillus niger, Aspergillus tamari and Aspergillus nomius). The pure hexane eluate showed potent antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Shigella sp. and moderate antifungal activity against Aspergillus nomius. This eluate also had a broad spectrum bactericidal activity. Gas chromatography separation and identification of the constituent compounds in the eluate showed that it was composed of 86 % fatty acid alkyl esters, 10.6 % oleic acid, 2.3 % 1,2-15,16-diepoxyhexadecane and 1.1 % Methoxycitronellal. Keywords: Vernonia amygdalina, Eluate, Hexane, Fatty acid alkyl ester, Oleic acid, Gas chromatography