Design, synthesis and biological evaluation of novel quinoline-based carboxylic hydrazides as anti-tubercular agents

In this study, seventeen novel quinoline-based carboxylic hydrazides were designed as potential anti-tubercular agents using molecular hybridization approach and evaluated in-silico for drug-likeness behavior. The compounds were synthesized, purified, and characterized using spectral techniques (like FTIR, (1) H NMR, and Mass). The in-vitro anti-tubercular activity (against Mycobacterium tuberculosisH37Ra) and cytotoxicity against human lung fibroblast cells were studied. Among the tested hydrazides, four compounds (6h, 6j, 6l, and 6m) exhibited significant anti-tubercular activity with MIC values below 20 μg/mL. The two most potent compounds of the series, 6j and 6m exhibited MIC values 7.70 and 7.13 μg/mL, respectively, against M. tuberculosis with selectivity index >26. Structure-activity relationship studies were performed for the tested compounds in order to explore the effect of substitution pattern on the anti-tubercular activity of the synthesized compounds.