Antimycobacterial activity of 5-arylidene aromatic derivatives of hydantoin.

Various 5-(chlorobenzylidene)-2-isoniazido and 5-(chlorobenzylidene)-2-amino substituted derivatives of imidazoline-4-one were synthesized and evaluated in the primary assay for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv. Eight of them exhibited > 90% inhibition in the primary screening at 12.5 microg/ml. For these primarily selected compounds the actual MIC and IC50 values were determined. Two of the isoniazid derivatives, for which MIC < 3.13 microg/ml and SI > 10, were selected for further screening and investigated for efficacy in vitro in a TB-infected macrophage model. The most promising compound, 5-(3-chlorobenzylidene)-2-(isonicotinoylhydrazino)-imidazoline-4-one, with activity in vitro comparable with rifampin (MIC = 0.8 microg/ml. SI > 78) was tested in vivo in the animal tuberculosis model but exhibited insignificant activity. For several compounds the primary screening of antimycobacterial activity against Mycobacterium avium (ATCC 25291) was conducted as well, but none of them demonstrated satisfactory activity.