Abstract

This study was conducted to investigate the antimicrobial activities of the methanolic extract of Rothmannia longiflora and Canna indica leaves against 10 pathogenic bacterial and fungal strains. The methanolic extract from the two plants were screened for their minimum inhibitory concentration (MIC) against the microbial growth of Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhi, Klebsiella pneumonia, Candida albicans, Aspergillus niger, Phjapus stolometer and Penicillium notatum. The results show that inhibition of microbial growth decreased with decreasing concentrations of the plant extracts. While concentrations of 200 and 100 mg/ml completely inhibited microbial growth, lower concentrations (50 and 25 mg/ml) showed partial inhibition, extracts at lower concentrations than these had no effects on microbial growth of microorganisms tested. Comparatively, R. longiflora gave better results than C. indica. This study confirmed the effectiveness of methanolic extracts of the two plants as inhibitory effect to microbial growth of several pathogenic microorganisms and testified to the basis of the ethnomedicinal uses of these two plants against several microbial infections. 

Key words: Antimicrobial potential, Rothmannia longiflora, Canna indica, bacteria, fungi, Nigeria, methanolic extract.