Evaluation of Antibacterial Activities and Cytotoxicity of Three Medicinal Plants Used for the Management of Mycobacterium tuberculosis and Staphylococcus aureus Infections in the North-West Region of Cameroon

Abstract

Introduction: Chemotherapy is used to combat tuberculosis, and other microbial infections. Unfortunately, resistance has been reported to a vast majority of currently use drugs. The objective of this study was to search for new therapies from plant products for the sustainable management of tuberculosis and S. aureus infections. Materials and Methods: Crude extracts were obtained by sequential maceration of dry powdered plant material in three solvents; hexane, dichloromethane and methanol. Phytochemical screening to identify active constituents in the crude extracts was done by conventional methods. The antimycobacterial and antimicrobial activity on M. tuberculosis control strain H37Ra and a clinical isolate of S. aureus respectively, was evaluated at eight different concentrations using the microplatealamar blue assay. Cytotoxicity of the active extracts was evaluated on monkey kidney epithelial cells and assessed using the MTT/formazan assay. Results: Twelve crude extracts were obtained, the hexane extract of Sanseviera liberica rhizomes (P3rH) showed antimycobacterial activity with a minimum inhibitory concentration (MIC) of 1 mg/mL. The hexane and methanol extracts of Emilia coccinea, P2H and P2M respectively, showed antimicrobial activity with MICs of 500 μg/mL and 1000 μg/mL respectively. P2M and P2H had selectivity indices of respectively, 0.1046 and 0.2336. Conclusion: This study validates the use of S. liberica and E. coccinea for the traditional management of tuberculosis and S. aureus infections, respectively. Furthermore, it provides a base for the purification of the active extracts and generation of leads in the search of alternative drugs for the management of these microbial infections.