Evaluation of the bioactive compounds of Vernonia amygdalina Delile extracts and their antibacterial potentials on water-related bacteria

Abstract

Abstract Background This study focused on the evaluation of the bioactive compounds of Vernonia amygdalina Del. leaf extracts and their antibacterial potential on some water-related bacterial isolates. The bacterial isolates were confirmed using standard microbiological test. The leaves of V. amygdalina were subjected to extraction using the Maceration method with water and ethanol as the extraction solvents. Gas chromatography–mass spectroscopy (GC–MS) was carried out on extracts. Antibacterial susceptibility test of V. amygdalina extracts on isolates was carried out. Results Aqueous extract of V. amygdalina had a higher percentage yield (11.89%) than the ethanol extract (5.37%). The GC–MS carried out revealed the presence of butanoic acid, squalene, palmitaldehyde, octadecanoic acid, Z-hexadecanoic acid ethyl ester, oxirane, tetradecyl, 3- methyl-2-phenylindole, n-heneicosane, phytol, methyl-2-O-benzyl-d-arabinofuranoside, cholest-5-en-3-ol acetate; with hexadecanoic acid ethyl ester and 1,1-diethoxy-3methylbutane having the highest percentage composition of 24.37% and 13.42% in aqueous and ethanol extract, respectively, aqueous extract highly inhibited Escherichia coli with an inhibition zone of 10.333 ± 0.882 and 36.667 ± 0.882 for 25 mg/ml and 100 mg/ml, respectively, while the ethanol extracts inhibited most of the isolates with an inhibition range of 7.000 ± 1.155 to 30.333 ± 0.882. The minimum inhibitory concentration for both extracts on the isolates varies from 25 to 50 mg/ml. Conclusions The ethanol extract of V. amygdalina had a higher inhibitory activity on the bacterial isolates than water. These findings indicate the potential of ethanol extract of V. amygdalina leaf in the treatment of water borne infections.

Keywords

• Bacteria
• Vernonia amygdalina
• Antibacterial
• Surface water