For instance, compound (39) exhibited MIC90 of 6.16 μM against an MDR-TB isolate and low cytotoxicity against mouse macrophage (RAW264.7) cell lines with IC50 of 222.92 μM. In addition, the authors performed docking studies on the mycobacterial pantothenate synthetase enzyme and compound (39) showed a good interaction in the enzyme active site with docking score of −9.2 kcal/mol . This enzyme is involved in the biosynthesis of coenzyme A and acyl carrier protein . The benzo[b]thiophene (40) also exhibited potent antituberculosis activity against a multidrug-resistant strain with MIC90 of 8.3 μM. Docking studies on the DprE1 enzyme were performed and compound (40) showed a docking score of −8.7 kcal/mol, suggesting that this enzyme could be the potential molecular target . Likewise, compound (41) showed a promising antitubercular activity against an MDR-TB strain with MIC90 of 2.4 μM. In vitro microsome stability study exhibited a T1/2 of 14.4 h and low inhibition of two isoforms of cytochrome P450, namely CYP3A4 and CYP2D6. Moreover, the authors suggested that compound (41) might act through inhibition of mycobacterial DNA-dependent RNA polymerase . The benzoxazole derivative (42) also showed to be a promising antituberculosis agent. The MIC90 evaluated for this compound was 3.2 μM against XDR-TB strains and it demonstrated in vivo activity similar to that of RMP in a mouse model infected with the selectable marker-free autoluminescent Mtb strain H37Ra .