ANTIBACTERIAL ACTIVITY OF THE ETHANOLIC EXTRACT OF LEAVES OF Citrus maxima (Burm.) Merr. ON ESCHERICHIA COLI AND PSEUDOMONAS AERUGINOSA

Objective: The objective of the study was to evaluate the antibacterial activity of the ethanolic extracts of leaves of Citrus maxima (Burm.) Merr. (EECM) on Escherichia coli and Pseudomonas aeruginosa. Methods: The ethanolic extract of leaves of Citrus maxima (Burm.)Merr.(EECM) was prepared by percolation method. Pathological isolates Escherichia coli and Pseudomonas aeruginosa were obtained from the Department of Microbiology, Assam Medical College & Hospital. Disc diffusion method for antimicrobial susceptibility testing was performed according to the Kirby-Bauer method. The whatman-1 filter paper discs of 6mm sizes impregnated with the plant extract were placed on Mueller-Hinton agar plates seeded with bacterial cultures of 0.5 Mc Farland standards. The antibacterial activities were assessed by the presence or absence of inhibition zones after incubating the plates at 37 0 c for 24 hours. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of EECM for the selected pathogens were determined by broth macrodilution method. Results: Maximum zone of inhibition in antibacterial susceptibility test was shown by Pseudomonas aeruginosa. MIC value of the extract for Pseudomonas aeruginosa (0.312mg/ml) was found to be lower than Escherichia coli but MBC value (1.25mg/ml) was found to be the same for both the bacteria. Conclusion: The plant extract of Citrus maxima (Burm.) Merr showed significant antibacterial activity against Escherichia coli and Pseudomonas aeruginosa. Keywords: Pseudomonas aeruginosa, Escherichia coli, MIC, MBC, Citrus maxima .