Assessment of Antibacterial and Antifungal Effects of Extracts of Four Plants

Abstract

The objective of this study was the determination of the antimicrobial activity of ethanolic, aqueous and petroleum ether extracts of four native plants [Acacia nilotica (Algrad) fruits, Psidum guajava (Guava) leaves, Lawsonia inermis(Henna) leaves and Capparis decidua (Tundub) shoot] against five bacterial and two fungalspecies. The bacterial species were Bacillus subtilis,Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosaand Klebsiela pneumoniae; and the fungal species were Aspergillus nigerand Candida albicans. Using the cup-plate agar diffusion method, the antimicrobial activity of the plant extracts (5%, 10%, 15% and 20% concentrations) was determined. Acacia nilotica extracts showed the highest antimicrobial activity, followed by those ofPsidum guajava, then Lawsonia inermis; and the extracts of Capparis deciduawere the least active. Ethanolic extracts of the four plant species showed the highest activity followed by aqueous extracts. Petroleum ether extracts were almost inactive against all organisms tested. The antibacterial activity of all extracts was far superior to their antifungal activity. B. subtilis was the most susceptible bacterium followed by S. aureusand then E. coli. Of the two fungal species, C. albicanswas much more susceptible than A. niger, which showed susceptibility only to ethanolic and aqueous extracts of Acacia nilotica. When the antibacterial activity of the plant extracts was compared with that of known antibacterial agents, the plant extracts werein most cases more v active. However, the antifungal activity of the plant extracts was more inferior to that of known antifungal agents.