Antimicrobial Activity of Xerophytic Plant (Cotula cinerea Delile) Extracts Against Some Pathogenic Bacteria and Fungi

In the present investigation, an Algerian commonly available plant namely Cotula cinerea, found throughout sandy desert grounds, was screening for antimicrobial activity against five different human pathogenic microbes namely, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. The antimicrobial activity was evaluated using the agar disc diffusion method. Aerial parts of C. cinerea were subjected to extraction using four solvents of different polarity (70% ethanol, n-butanol, ethyl acetate and petroleum ether). Petroleum ether and n-butanol extracts had the most effective antimicrobial activity with Gram-negative K. pneumoniae demonstrating the highest susceptibility. Linear regression analysis was performed to find correlations between extract concentrations and inhibition activity. Results showed a significant increase in mean diameter of inhibition zone with increasing extract concentrations of all solvents except n-butanol. Two-way ANOVA test was used to compare the effect of C. cinerea extracts on the antimicrobial properties. All plant extracts have shown significant differences in their actions as antimicrobial agents. Indeed, the n-butanol extract at a low concentration of 0.25 mg mL-1 indicated a potent antimicrobial activity of C. cinerea extracts.