3,5-dinitrobenzoylhydrazone derivatives as a scaffold for antituberculosis drug development.

Background: The development of drugs is essential to eradicate tuberculosis. Materials & methods: Sixteen 3,5-dinitrobenzoylhydrazone (2-17) derivatives and their synthetic precursors 3,5-dinitrobenzoylhydrazide (1) and methyl ester (18) were screened for their anti-Mycobacterium tuberculosis (Mtb) potential. Results: Twelve compounds had minimum inhibitory concentration (MIC) ranging from 0.24 to 7.8 µg/ml against the Mtb strain. The activity was maintained in multidrug-resistant Mtb clinical isolates. Only compound (17) showed activity against nontuberculous mycobacteria. The compounds exhibited a limited spectrum of activity, with an MIC >500 µg/ml against Gram-positive and -negative bacteria. Compounds (2), (5) and (11) showed a synergistic effect with rifampicin. An excellent selectivity index value was found, with values reaching 583.33. Conclusion: 3,5-dinitrobenzoylhydrazone derivatives could be considered as a scaffold for the development of antituberculosis drugs.

Hydrazone, benzohydrazones and isoniazid-acylhydrazones as potential antituberculosis agents.

Aim: To evaluate the potential of three benzohydrazones (1-3), four acylhydrazones derived from isoniazid (INH-acylhydrazones) (4-7) and one hydrazone (8) as antituberculosis agents. Materials & methods: Inhibitory and bactericidal activities were determined for the reference Mycobacterium tuberculosis (Mtb) strain and clinical isolates. Cytotoxicity, drug combinations and ethidium bromide accumulation assays were also performed. Results: The tested compounds (1-8) presented excellent antituberculosis activity with surprisingly inhibitory (0.12-250 µg/ml) and bactericidal values, even against multidrug-resistant Mtb clinical isolates. Compounds showed high selectivity index, with values reaching 1833.33, and a limited spectrum of activity. Some of the compounds (2 & 8) are also great inhibitors of bacillus efflux pumps. Conclusion: Benzohydrazones and INH-acylhydrazones may be considered scaffolds for the development of new anti-Mtb drugs.