Quantum computational, spectroscopic investigation, molecular docking, and in vitro pharmacological studies of sulfonamide Schiff base

Abstract

A new Schiff base, (E)-4-((3,5-dibromo-2-hydroxybenzylidene)amino)-N-(5-methylisoxazol-3-yl)benzenesulfonamide was synthesized and characterized by various physico-chemical, X-ray crystallography and DFT methods. The experimental findings were compared with the computed data. The characteristic azomethine band was found at 1616 cm−1 in the experimental FTIR spectrum. The double bond distance between C7=N1 was 1.277(5) Å. Single X-ray crystallography data indicated that the crystal system of the compound was monoclinic with space group P21/c. The experimental values were well correlated with the computed ones. The kinetic stability of the compound was high due to the larger HOMO-LUMO energy gap. Molecular docking and POM (Petra/Osiris/Molinspiration) investigation of the compound were also performed. POM analysis identified one antibacterial and two antitumor pharmacophore sites in the compound. It exhibited higher binding energy than the reference drug in molecular docking study. The compound followed Lipinski's rule of five and exhibited promising drug-like character and drug score. Moreover, in vitro anticancer, antibacterial, antifungal, anti-inflammatory and antioxidant properties of the compound were also carried out. It showed good antibacterial effects against S. aureus and S. typhi strains. In case of antifungal activity, the compound showed moderate inhibitory activity against both A. niger and A. flavus strains. Besides, it has the capability to stabilize the human red blood cell membrane in hypotonic solution and protect hemolysis. The highest cytotoxic activity of the compound with IC50 value of 65.344 μg/mL was observed against A549 lung cancer cells. Finally, the compound showed moderate antioxidant activity with IC50 value of 4.25 μM.