Methanol Extract of Three Medicinal Plants from Samburu in Northern Kenya Show Significant Antimycobacterial, Antibacterial and Antifungal Properties

Abstract

We determined the antimycobacterial, antibacterial, and antifungal potential of medicinal plants used by the Samburu Community of Northern Kenya, following an ethnobotanical survey. Using BACTEC MGIT 960 system, we assessed plant extract effects on four mycobacterial strains, i.e., Mycobacterium tuberculosis, M. Kansasii, M. fortuitum, and M. smegmatis. For Candida albicans, Salmonella typhi, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumonia, we determined zones of inhibition, Minimum Inhibitory Concentrations (MICs) and minimum bactericidal/fungicidal concentrations (MBCs/MFCs) using standard procedures. Preliminary phytochemistry on the extracts was also carried out using standard procedures. The extracts from Scadoxus multiflorus and Acacia nilotica gave strong antimycobacterial activity (zero GUs) against slow growing mycobacteria strains in all the concentrations tested. Scadoxus multiflorus was also active against M. tuberculosis. Boscia angustifolia was active against M. tuberculosis (183 GUs). Acacia nilotica showed strong antimicrobial activity against E. coli (with of MIC 4.69 mg mL-1 and MBC of 18.75 mg mL-1), P. aeruginosa (with both MIC and MBC of 18.75 mg mL-1), K. pneumoniae, and C. albicans (with MIC of 9.38 mg mL-1 and MBC of 18.75 mg mL-1). Thylachium africanum showed good antimicrobial activity against S. aureus (with MIC of 18.75 mg mL-1 and MBC of 37.5 mg mL-1) and P. aeruginosa (with both MIC and MBC of 4.69 mg mL-1). Preliminary phytochemistry identified six phytochemicals to which tannins was common to all plant extracts. The data suggests that methanolic extracts of at least three plant species could be a rich source of antimicrobial agents. These results provide an indication of merit in their ethnomedicine use by the local communities.