Antitubercular, Cytotoxicity, and Computational Target Validation of Dihydroquinazolinone Derivatives

Abstract

A series of 2,3-dihydroquinazolin-4(1<i>H</i>)-one derivatives (<b>3a</b>-<b>3m</b>) was screened for in vitro whole-cell antitubercular activity against the tubercular strain H37Rv and multidrug-resistant (MDR) <i>Mycobacterium tuberculosis</i> (MTB) strains. Compounds <b>3l</b> and <b>3m</b> with di-substituted aryl moiety (halogens) attached to the 2-position of the scaffold showed a minimum inhibitory concentration (MIC) of 2 µg/mL against the MTB strain H37Rv. Compound <b>3k</b> with an imidazole ring at the 2-position of the dihydroquinazolin-4(1<i>H</i>)-one also showed significant inhibitory action against both the susceptible strain H37Rv and MDR strains with MIC values of 4 and 16 µg/mL, respectively. The computational results revealed the mycobacterial pyridoxal-5'-phosphate (PLP)-dependent aminotransferase (BioA) enzyme as the potential target for the tested compounds. In vitro, ADMET calculations and cytotoxicity studies against the normal human dermal fibroblast cells indicated the safety and tolerability of the test compounds <b>3k</b>-<b>3m</b>. Thus, compounds <b>3k</b>-<b>3m</b> warrant further optimization to develop novel BioA inhibitors for the treatment of drug-sensitive H37Rv and drug-resistant MTB.