Evaluation of Antimicrobial Activity of Anogeissus leiocarpus and Terminalia avicennioides against Infectious Diseases Prevalent in Hospital Environments in Nigeria

The crude methanol extracts of the two plants selected on the basis of ethnobotanical uses were phytochemically screened and found to contain saponins, steroids, tannins, terpenes, anthraquinone and carbohydrates. The crude methanolic extracts exhibited broad growth inhibition against Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa, Neisseria gonorrhoea and Candida albicans. The Minimum Inhibition Concentration (MIC) of Anogeissus leiocarpus methanol extract was found to be 0.4 mg/mL against S. aureus, St. pyogenes, P. aeruginosa and N. gonorrhoea, while B. subtilis has the MIC of 0.3 mg/mL. The rest of the microorganisms were resistant to Anogeissus leiocarpus methanol extract. Terminalia avicennioides methanol extract has the MIC of 0.4 mg/mL on S. aureus, S. typhi, E. coli, P. aeruginosa, N. gonorrhoea and C. albicans. Both S. pyogenes and B. subtilis have the MIC of 0.3 mg/mL against Terminalia avicennioides methanol extract. The rest of the microorganisms were resistant. Both Corynebacterium ulcerans and Klebsiella pneumoniae were resistant to the two plant extracts. The present investigation justify the use of these extracts in the treatment of infectious diseases particularly those caused by S. pyogenes having the highest zone of inhibition as well as the lowest MIC (0.3 mg/mL) for the two plants. Further purification of the most promising extracts is currently being undertaken.