<em>In-vitro </em>antibacterial activity of <em>Boerhavia diffusa</em> leaf extract against <em>Staphylococcus aureus </em>and<em> Escherichia coli</em>

Abstract

Plants are playing a significant role in maintaining human health and improving the wealth of human life and are a better alternative to synthetic drugs that display negative side effects, such as sensitization reactions, and disruption of the metabolic processes in the body via interaction with the body system. The main objective of this study was to evaluate the in-vitro antibacterial activity of Green Leafy Vegetable (GLVs), namely Boerhavia diffusa. Fully matured fresh leaf samples were collected from different localities in the Western Province, Sri Lanka. The acetone, ethanol and aqueous extracts of leaf samples were tested for antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), by using agar well diffusion method at the test concentrations of 0.25, 0.50 and 0.75 mg/μL. The maximum inhibitory effect was observed in the ethanol extracts of leaf samples against both bacterial strains at 0.75 mg/μL concentration. Ethanol extract of B. diffusa showed the maximum inhibition effect (17.8±0.3 mm) against S. aureus and it was the most susceptible bacteria than E. coli in plant extracts of all three solvents. All three extracts of B. diffusa showed most effective antibacterial activity against both bacterial strains, tested. The MIC values obtained from plants exhibited antibacterial activity ranged between 0.0625 and 0.25 mg/μL. The lowest MIC values were given by the ethanol extracts. Thus, the ethanol extract of this plant leaf sample was the most effective extract, which exhibited strong antimicrobial activity on both bacterial strains. Presence of bioactive compounds in these plant extracts could be the reason to indicate high antibacterial activity.