Assessment of Phytochemical Screening of Vernonia amgydalina Lin Leaves and its Antibacterial Potential on Salmonella typhi and Staphylococcus aureus

Abstract

The phytochemical screening of Vernonia amygdalina Lin leaves and its antibacterial potential on Salmonella typhi and Staphylococcus aureus were investigated using standard methods. The Wattman No 1 sterilized paper discs (6mm in diameter) impregnated with Vernonia amygdalina ethanolic and aqueous extracts at the concentrations of 20 mg/ml, 10 mg/ml, 5 mg/ml and 2.5 mg/ml were tested on Salmonella typhi and Staphylococcus aureus. The zones of inhibition shown by the extracts at different concentrations against different strains, the turbidity of broth culture (susceptibility), Minimal Inhibitory Concentration (MIC) and bacterial growth Minimal Bactericidal Concentration (MBC) of the test organisms were studied. Susceptibility test revealed that VAEE have antimicrobial activities for Salmonella typhi and Staphylococcus aureus (clinical, reference and environmental strains). There was significantly higher difference with respect to the zones of inhibitions produced among the various extract concentrations against the test organisms (ANOVA P<0.05). The strains of S. typhi and S. aureus showed MIC and MBC at the extract concentrations of 10 mg/ml and 20 mg/ml respectively. The findings of this study suggested ethanol to be a good solvent for the extraction of the antibacterial substances in VA. Furthermore, some constituents; saponin tannin, flavonoid and alkaloid were shown to be presence in the leaves of VA, hence could be isolated and developed in to effective antimicrobial agents.