Antimicrobial potentials of Mentha longifolia by disc diffusion method

This study was conducted for the assessment of the antimicrobial activities of different solvents extracted samples from the aerial parts of Mentha longifolia against ten microbial species through the disc diffusion assay using two different concentrations of 1 and 2 mg disc1. All extracts from Mentha longifolia showed different ranges of antimicrobial activities. Butanol and ethyl acetate fractions showed inhibitory activities against all microbial species. Methanol fraction showed inhibitory effects against all the tested microbial species except Salmonella typhi. Salmonella typhi was also not controlled by methanol, petroleum ether and dichloromethane extracted samples. The most susceptible gram positive bacteria was Bacillus atropheus and Bacillus subtilis and were inhibited by all extracts and Staphylococus aureus was least susceptible among gram positive bacteria. Klebsiella pneumoniae was the most susceptible gram negative bacterium and Salmonella typhi was highly resistant among the gram negative bacteria. Erwinia carotovora and Agrobacterium tumefaciene were susceptible to all fractions. All fractions showed antifungal activities against Candida albicans except water extracted samples.