Inhibitory activities of selected South West Nigerian medicinal plants against Mycobacterium tuberculosis

Abstract

Introduction: Tuberculosis (TB), an infectious disease prevalent in the tropics especially in Africa and Asia is one of the highest causes of morbidity and mortality and a global concern. With increasing resistance of the pathogen, to existing anti-tuberculosis drugs and the synergy between TB infection and acquired immune deficiency syndrome (AIDS), the need for development of new drugs to cope with the infection is urgent. Objective: Extracts from 16 plants identified and selected from the ethnomedicine of the Ijebus in Southwestern Nigeria as remedies for tuberculosis were evaluated for activity against Mycobacterium tuberculosis, in vitro. Methodology: Plant extracts were screened against clinical isolate of Mycobacterium tuberculosis using agar plate method on Middlebrook 7H11 medium and observed for 12 weeks. Results: The crude aqueous methanol extracts. showed varying degrees of activity at concentrations of 0.025 - 100 mg/mL. Ocimum grattisimum (leaf) demonstrated the highest activity with minimum inhibitory concentration (MIC) of 0.025 mg/mL. Two standard anti-tuberculosis drugs; rifampicin and isoniazid, included in the assay had MIC values of 0.01 mg/mL and 0.0005 mg/mL, respectively. Conclusion: The results of the study confirm the ethnopharmacological uses of some of the plants for TB indicating their potential as sources for the discovery of anti-tuberculosis drugs.