Antimicrobial Activities of Two Medicinal Plants used by Ethnic Communities of Assam Against Some Clinically Significant Human Pathogens

Abstract

In the present investigation antimicrobial activity of two medicinal plants used by ethnic communities of Assam was undertaken. Altogether, three organic solvents namely ethanol, methanol and petroleum ether were used to obtain the plant extracts. Antimicrobial activity of the extracts was determined by Agar Diffusion methods against some clinically significant human pathogens. The leaf extracts obtained in different organic solvents of L. chinensisshowed considerable antimicrobial activity against the test pathogens. The result indicated that both methanol and ethanol extracts showed better activity than petroleum ether extract. Significant zone of inhibition was showed against the fungal pathogens namely C. albicans and C. krusie. Similarly, the bacterial pathogens were also found to be susceptible to the ethanol extract. Highest zone of inhibition was observed against Staphylococcus aureusfollowed by Shigellaflexneri. No zone of inhibition was observed in aqueous extract. A similar result was also obtained in the solvent extracts of Streblus asper. The crude organic solvents inhibited both bacterial and fungal pathogens in varying degree. Promising zone inhibition was showed against C. krusei and C. albicans in the ethanol extract. Similarly, the bacterial pathogens were also found to be susceptible to the ethanol extract. Highest zone of inhibition was observed against Staphylococcus aureusfollowed by Pseudomonas aeruginosa. The aqueous extracts of both plant species did not show any activity against the test pathogens. The study indicated that medicinal plants used by ethnic communities could be explored for effective antimicrobial agents to combat drug resistant pathogenic microorganisms.