Schiff base of isoniazid and ketoprofen: synthesis, X-ray crystallographic, spectroscopic, antioxidant, and computational studies

摘要

Ketoprofen and isoniazid together are a potential combination of a nonsteroidal antiinflammatory drug and an antitubercular medicine to treat tuberculosis and associated symptoms like fever and fatigue. The Schiff base of isoniazid with ketoprofen is synthesized in this research. Infrared spectroscopy (IR) and X-ray diffraction (XRD) analysis of the crystal packing proved the formation of the Schiff base and the existence of N-H$cdot cdot cdot $O hydrogen bonds between the hydrogen-bonded dimer of the Schiff base. The complete geometrical optimization of the monomer and hydrogen-bonded dimer of the Schiff base is performed utilizing M06-2X/6-31G(d,p) level theory and compared with the experimental data to optimize the molecular structure. The effect of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity shows that the synthesized Schiff base has improved antioxidant activity. Molecular docking studies against Mycobacterium tuberculosis (Mtb) RNA polymerase-related targets with PDB codes 2M6O and 4KBJ and lung surfactant protein A (SP-A) with PDB ID 5FFT suggest that it can be screened as a potent drug against Mtb infection of the lungs. Frontier orbital theory analysis shows a high energy gap between the HOMO and LUMO, which suggests that the reported Schiff base might be a bioactive compound. Different experimental (XRD, IR, thermal gravimetric analysis, differential scanning calorimetry) and computational studies correlate and validate findings related to this novel Schiff base.