Microbiology Research Journal International

This research was aimed to contribute to the previous knowledge of combating pathogens by using local medicinal plants in Bangladesh. In the present work, the antibacterial activity of Paan (Piper betel leaves) and Black cumin (Nigella sativa seeds) extracts in water as well as in various organic solvents (namely methanol and ethanol) were analyzed against food and waterborne pathogenic bacteria (both gram-positive and gram-negative) viz. Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and Bacillus subtilis, all of which were previously found to be resistant to different antibiotics. Methanol extracts of Piper betel was the best extract in inhibiting the growth of gram-positive bacteria, secondly aqueous and ethanol extracts were less effective as antibacterial agents except against S. aureus while gram-negative bacteria, only S. typhi and P. aeruginosa were found to be sensitive to aqueous extracts. Methanol extracts of Black cumin was effective against gram-negative where ethanol extracts were effective against gram-positive but S. typhi was sensitive to both ones. When extracts were compared with the traditional antibiotics, this activity was especially competent against S. aureus followed by B. cereus and B. subtilis. When Betel extracts were compared with the traditional antibiotics, this activity was especially competent against E.coli followed by S. typhiand P. aeruginosa. The broth dilution assay revealed that the bactericidal values for both the plant extracts fall in the range of 1125 to 2250 µg/ml. These results suggest that betel leaves and black cumin seeds have potential antibacterial activity against multiple antibiotic-resistant bacteria.