Evaluation of anti-Mycobacterium tuberculosis activity of fractions from selected medicinal plants used traditionally for treating cough and respiratory disorders in South West of Nigeria

Tuberculosis is a contagious airborne infection that mostly affects the lungs. The causative agent of tuberculosis in human is Mycobacterium tuberculosis. The emergence and dissemination of M. tuberculosis isolates that are resistant to multiple antimicrobial drugs represent a growing public health threat. Fractions from Alafia barteri, Chasmanthera dependence, Chrysophyllum albidum, Emilia coccinea, Mezoneuron benthamianum, Phyllanthus muellerianus, Secamoni afzeli, Senna alata, Xylopia aethiopica and Acalypha fimbriata were screened for activity against drug susceptible M. tuberculosis H37Rv and the local isolates using proportion and nitrate reduction methods. The organisms used were M. tuberculosis H37Rv strain and the local isolates from TB patients. The standard antitubercular drugs used were isoniazid and rifampicin. No fractions from A. barterii, C. dependens, E. coccinea, S. afzeli, S. alata and X. aethiopica showed sensitivity against the M. tuberculosis strains. The hexane fraction of C. albidum, butanol fraction of M. benthamianum, ethyl acetate fraction of P. muellerianus and ethyl acetate fraction of A. fimbriata showed sensitivity with minimum inhibition concentration of 0.5 mg/ml. The ethylacetate and hexane fractions of M. benthamianum together with hexane fraction of P. muellerianus showed sensitivity with MIC value of 1.25 mg/ml. The highest MIC value of 2.5 mg/ml was obtained from hexane fraction of A. fimbriata. Thus, C. albidum, M. benthamianum, P. muellerianus and A. fimbriata possessed antimycobacterium tuberculosis activity and further research work would be required to assess possible antitubercular agents present in the four medicinal plants. Key words: Tuberculosis, anti-mycobacterium, fractions, sensitivity and inhibition.