Antimicrobial activity and GC-MS analysis of some ethno medicinal plants used by Santali tribe of Assam

Abstract

The increasing occurrence of antimicrobial resistance has become a major global threat, calling for the exploration of alternative antimicrobial agents derived from natural resources, including ethnomedicinal surveys of plants. This study evaluated the comparative antimicrobial activity of crude ethanolic extracts of the following ethnomedicinal plants used by Santali tribe of Kokrajhar district of Assam, India- Clerodendrum infortunatum, Piper nigrum, Psidium guajava, Camellia sinensis, Andrographis paniculata and Murraya koenigi against three bacterial pathogens, Staphylococcus aureus, Escherichia coli (non pathogenic), Salmonella typhi and two fungal pathogens, Candida albicans and Aspergillus fumigatus. Antimicrobial activity was evaluated using the agar cup/disk diffusion method, and inhibition zones were statistically analyzed by using mean data and standard deviation. C. sinensis showed highest antimicrobial activity (22.33±0.93 mm against E. coli) followed by P. guajava (20±1.63 mm against E. coli) and A. paniculata (19±0.81mm against S. aureus). P. nigrum and M. koenigi showed moderate inhibition while C. infortunatum exhibited comparatively lower activity. GC-MS analysis revealed several bio active compounds, including piperine, hexamethyl cyclotrisiloxane, methyl thiophene-2-carboxylate and tetradecamethyl cycloheptasiloxane. The results support ongoing efforts to identify alternative natural, plant-derived agents to tackle antimicrobial resistance.