ABSTRACT:
The antimicrobial activity of leaf extracts of four indigenous medicinal plants (Cassia auriculata, Psidium guajava, Carica papaya, and Adathoda vasica, of families Caesalpinaceae, Solanaceae, Caricaceae and Acanthaceae) were evaluated on four bacterial strains (staphylococcus aureus (MTCC 96), Escherichia coli (MTCC 738), Enterobacter aerogenes (MTCC 2990) and Serratia marscens (MTCC 2645)). The Methanol, Ethyl acetate and Aqueous extracts were obtained by soxhlet apparatus and antimicrobial activity was found using disc diffusion method. Results of phytochemical analysis indicated that out of 12 extracts (from four plants and three solvents) ethyl acetate extract of Adathoda vasica exhibited maximum antimicrobial activity against all the four tested microorganisms. Ethyl acetate extract of Adathoda vasica showed maximum inhibition (31mm) zone towards the microorganism staphylococcus aureus and 23mm, 18mm, 15mm zones of inhibition against Enterobacter aerogenes, Serratia marscens and Escherichia coli respectively. Methanol extracts of Psidium guajava and Carica papaya also found to be effective against E. coli with zones of inhibition 27mm and 25 mm respectively. The antibacterial activity of active extracts was compared with the antibiotic, Streptomycin. Comparative studies with antibiotic streptomycin showed that ethyl acetate extract of Adathoda vasica against S. aureus, methanolic extracts of psidium guajava and Carica papaya against E.coli were found to be more effective compared to streptomycin. This study demonstrates potentials of all above plants as source of antimicrobial activities that could be harness for use in the health care delivery process.