DETERMINATION OF ANTI-TUBERCULAR ACTIVITY OF FOUR INDIAN MEDICINAL PLANTS AGAINST MYCOBACTERIUM TUBERCULOSIS BY BROTH MICRO DILUTION METHOD

Tuberculosis is one of the oldest killer diseases of mankind. It is an airborne communicable disease caused by transmission of aerosolized droplets of Mycobacterium tuberculosis. The increasing incidence of MDR- and XDR-TB worldwide highlighted the urgent need to search for newer anti-tuberculosis compounds/drugs.The World Health Organization (WHO) estimated that approximately 80% of world population relies mainly on traditional medicines, mostly plant drugs in their health care. The higher plant extracts are promising sources of novel anti-TB leads. Screening and estimation of lyophilised aqueous, aqueous ethanol and ethanolic extracts of four traditional Indian medicinal plants Acalypha indica, Adhatoda vasica, Allium cepa and Allium sativum for anti-tubercular activity tostandard strain H37Rv, clinical isolate of Isoniazid mono resistant and poly resistant isolates by the sensitive and reliable Broth Microdilution Method (BMM). Inhibition of M. tuberculosis isolates was observed for two of the four medicinal plants. All the three extracts of Allium sativum were found to be active in broth dilution assays with MIC of 500µg/ml and higher against the tested strains. The ethanolic extract of Allium cepa was found to be active with MIC of 500µg/ml against the tested strains. While the extracts of A. vasica and A. indica did not inhibit the growth of M. tuberculosis even at 500 µg/ml.  The extracts active against M. tuberculosis were evaluated for cytotoxicity. The maximal toxic free concentration on Vero cells were at 500μg/ml showing that the extracts were not toxic to Vero cells in the concentrations tested.