Isoniazid-isatin hydrazone derivatives: Synthesis, antitubercular activity and molecular docking studies

This study examined the synthesis of isoniazid-isatin hydrazone derivatives 5-7, followed by an investigation on the in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv and molecular docking. A yield of 81-92% of these compounds was achieved, with structural characterization by spectroscopic methods (FTIR, NMR, HRMS). The in vitro antitubercular activity was evaluated against M. tuberculosis H37Rv, and the highest effect was observed in compound 7, with a minimum inhibitory concentration (MIC) of 0.017 mM, lower than rifampicin (MIC 0.048 mM), which served as the positive control. In addition, the molecular docking of 5-7 was performed to visualize the interaction of isoniazid-isatin hydrazone derivatives with the active site of InhA receptor, which was in agreement with the experimental data. The hydrogen bonding with Ser94 and π-π interaction with Phe41 and/or Phe97 on the InhA active site was pivotal for the antitubercular activity.