In vitro antimycobacterial activity and interaction profiles of diarylthiourea-copper (II) complexes with antitubercular drugs against Mycobacterium tuberculosis isolates.

The activity of several halogenated copper (II) complexes of 4-chloro-3-nitrophenylthiourea derivatives has been tested against Mycobacterium tuberculosis strains and strains of non-tuberculous mycobacteria. The compounds were 2-16 times more potent than current TB-drugs against multidrug-resistant M. tuberculosis 210. The 3,4-dichlorophenylthiourea complex (5) was equipotent to ethambutol (EMB) towards M. tuberculosis HRv and 192 strains. All derivatives acted 2-8 times stronger than isoniazid (INH) against nontuberculous isolates. In the presence of chosen coordinates, the 2-64 times reduction of MIC values of standard drugs was denoted. The synergistic interaction was found between the complex 4 and rifampicin (RMP), and additivity of 1-5, 8 in pairs with EMB and/or streptomycin (SM) against M. tuberculosis 800 was established. All coordination compounds in combination with at least one drug showed additive activity towards both HRv and 192 isolates. In 67% incidences of indifference, the individual MIC of a drug decreased 2-16-fold. One can conclude that the novel thiourea chelates described here are potent hits for further developments of new agents against tuberculosis.