Antitubercular activity of new coumarins

The present article describes a series of 21 N '-benzylidene-2-oxo-2H-chromene-3-carbohydrazides 4a-4v, which were synthesized and evaluated for their cell viabilities in non-infected and Mycobacterium bovis Bacillus Calmette-Guerin-infected macrophages. Subsequently, the non-cytotoxic compounds 4c, 4g, 4h, 4j, 4l and 4t were assessed against Mycobacterium tuberculosis ATCC 27294 using the microplate Alamar Blue assay and the activity expressed as the minimum inhibitory concentration in μg/mL. These compounds exhibited a significant activity (50-100 μg/mL) when compared to the first-line drugs, such as pyrazinamide (PZA >100 μg/mL). These results could be considered a good starting point for further studies to develop new lead compounds to treat multidrug-resistant tuberculosis.