Novel isoniazid derivative as promising antituberculosis agent.

Background: A major focus of tuberculosis drug discovery is aimed at the development of novel antibiotics with activity against drug-resistant strains of Mycobacterium tuberculosis. Results: We have synthesized ten isoniazid derivatives and investigated for antibacterial activity toward M. tuberculosis H37Rv and isoniazid-resistant strain SRI 1369. It was revealed that only one compound, isonicotinic acid (1-methyl-1H-pyrrol-2-ylmethylene)-hydrazide (1), is active toward isoniazid-resistant strain with minimum inhibitory concentration value of 0.14 µM. This compound is not cytotoxic toward human liver cells (HepG2; IC50 >100 µM), demonstrates good permeability in Caco-2 cells. Accordingly to the results of plasma protein binding assay, unbound fraction of compound 1, which potentially exhibits pharmacologic effects, is 57.9%. Conclusion: Therefore, isonicotinic acid (1-methyl-1H-pyrrol-2-ylmethylene)-hydrazide is a promising compound for further preclinical studies.

Benzaldehyde thiosemicarbazone derivatives against replicating and nonreplicating Mycobacterium tuberculosis.

In this article, we report a series of benzaldehyde thiosemicarbazone derivatives possessing high activity toward actively replicating Mycobacterium tuberculosis strain with minimum inhibitory concentration (MIC) values in the range from 0.14 to 2.2 µM. Among them, two compounds-2-(4-phenethoxybenzylidene)hydrazine-1-carbothioamide (13) and 2-(3-isopropoxybenzylidene)hydrazine-1-carbothioamide (20) also demonstrate submicromolar antimycobacterial activity against M. tuberculosis under hypoxia with MIC values of 0.68 and 0.74 µM, respectively. The activity of compounds 13 and 20 toward five investigated isoniazid-, rifampicin-, and fluoroquinolone-resistant M. tuberculosis isolates is similar to commercially available antituberculosis drugs. The compounds 13 and 20 possess good ADME properties and have low cytotoxicity toward human liver cells (HepG2). Therefore, 2-(4-phenethoxybenzylidene)hydrazine-1-carbothioamide (13) and 2-(3-isopropoxybenzylidene)hydrazine-1-carbothioamide (20) are valuable candidates for further preclinical studies.