IN-VITRO INHIBITION OF MYCOBACTERIA BY RWANDESE MEDICINAL-PLANTS

A series of 15 Rwandese medicinal plants used by traditional healers t o treat pulmonary diseases were screened for anti-Mycobacterium tuberc ulosis activity. Three plant extracts showed activity at 1000 mug/mL: Bidens pilosa (leaves), Pentas longiflora (roots) and Tetradenia ripar ia (leaves). These plant extracts were studied further against several mycobacterial species: M. tuberculosis, M. avium complex, M. simiae a nd a new simiae like Mycobacterium species (SLM). None of the plant ex tracts showed activity against M. avium and SLM at 1000 mug/mL. M. sim iae was sensitive to T. riparia and P. longiflora extracts (1000 mug/m L) and M. tuberculosis towards T. riparia (500 mug/mL) and B. pilosa ( 100 mug/mL). The active principle of T. riparia, 8(14), 15-sandaracopi maradiene-7alpha, 18-diol, was also evaluated for its antimycobacteria l activity and the concentration required for inhibiting M. tuberculos is ranged from 25 mug/mL to 100 mug/mL. The extract of the leaves of T . riparia can be used as a differentiation test (at 1000 mug/mL in the medium) for M. simiae and SLM.