The objective of this research is to investigate the in vitro antimicrobial activity of two species of lichen isolated from the Similipal Biosphere Reserve (SBR), Parmotrema andium and Dirinaria applanata. Two test species were extracted with the solvents, methanol and acetone, and the extracts were tested against four human pathogenic bacteria and fungi. The antimicrobial activity was carried out by agar well diffusion method along with determination of minimum inhibitory concentration (MIC) by broth microdilution method. The study results revealed that the solvent extracts of both the lichen species showed highest antimicrobial activity against Vibrio cholerae with larger zone of inhibition (20 ± 0.85 mm). The antibacterial activity was found to be more promising than the antifungal activity. Among the lichen species, D. applanata was found to have better antimicrobial activity as compared to P. andium as evidenced from the size of zone of inhibition. In terms of antimicrobial properties, solvent extracts of lichens were more active, with MICs ranging from 62.5 to 500 μg/ml.
Key words: Antimicrobial, extract, lichen, MIC, phytochemicals
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