In vitro antimicrobial activity of crude ethanol extracts and fractions of Terminalia catappa and Vitex doniana.

BACKGROUND: The spread of microorganisms resistant to some antimicrobial agents necessitates the need to search for novel and effective antimicrobial agents. In this study, the antimicrobial activity of Terminalid catappa Linn. (Combretaceae) and Vitex doniana Sweet. (Verbenaceae), two Nigerian medicinal plants used in folk medicines for the management of various ailments related to microbial infections were evaluated. OBJECTIVES: To evaluate the antimicrobial activity of the crude ethanol extracts and fractions of the leaves and stem bark of T. catappa and V. doniana. METHODOLOGY: Four crude ethanol extracts and 16 (n-hexane, ethylacetate, n-butanol and aqueous) fractions of leaves and stem bark of T. catappa and V doniana were evaluated for in vitro antimicrobial activity against fifteen (15) strains of bacteria and fungi. The antimicrobial activity was determined in a 96-well plate using a resazurin based broth microdilution method. Two standard antimicrobial drugs ampicillin and nystatin were included as positive control. RESULTS: The butanoL fraction of stem bark of T. catappa and ethanol crude extract of leaf of V don iana displayed the highest antibacterial activity with similar minimum inhibitory concentration (MIC) value of 93.75 microg/mL against S. aureus and B. subtilis. Furthermore, the ethyl acetate fraction of stem bark of T. catappa showed the highest antifungal activity with MIC of 187.5 microg/mL against A. sydowi. Amp icillin had MIC of 15.6 and 31.3 microg/mL against S. aureus and B. subtili, respectively while nystatin produced MIC of 3.9 microg/mL against A. sydowi. CONCLUSION: Termninalia catappa and Vitex doniana may serve as useful sources of plant derived antimicrobial agents.

Inhibitory activities of selected south west Nigerian medicinal plants against mycobacterium tuberculosis.

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 antituberculosis 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.