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

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