COMPARATIVE ANTIMICROBIAL ACTIVITIES OF NEEM AND CURRY LEAF EXTRACTS AND THEIR SYNERGISTIC EFFECT AGAINST SELECTED PATHOGENIC BACTERIA AND FUNGUS

Abstract

There is a growing demand today for naturally derived drugs and medicine in place of synthetic drugs that are more commercially available. Such drugs derived from indigenous plants are effective as they contain potent therapeutically active compounds of the plants that show antimicrobial activity against a variety of pathogens that cause common diseases. Such diseases as periodontitis and oral candidiasis are a growing concern these days. This study was undertaken to investigate the antimicrobial activity of two indigenous Indian plants, Azadirachta indica and Murraya koenigii and their synergistic effect, if any, against three pathogenic microorganisms associated with oral diseases and one pathogenic bacteria known to be a nosocomial causative agent. Three bacterial species (Streptococcus mutans, Streptococcus gordonii, Pseudomonas aeruginosa) and one fungal species (Candida albicans) were selected for antimicrobial assays. Both ethanolic and methanolic extracts were prepared from the leaves of the two plant species in addition to an aqueous extract of A. indica and an n-hexane extract of M. koenigii. Antibacterial and antifungal assay was done using agar well diffusion method under standard culture conditions. Inhibitory activity was observed for all extracts against P. aeruginosa while A. indica and M. koenigii showed ineffectiveness in inhibiting growth of C. albicans and S. mutans respectively. C. albicans and S. mutans were selected for study of synergistic effect based on the results of the initial assay, however there was no synergistic activity observed for any combination of extract mixtures.