New perspectives on old drugs: Bioactive potentials of pyridazine sulfa drug Schiff bases and copper(II) complexes.

Integrating various bioactive structural components into a single molecule typically enhances the overall pharmacophoric efficacy. In this study, a new series of pyridazine sulfa drug Schiff bases and their copper(II) complexes was synthesized. All molecules were investigated for their in-vitro and in-silico antioxidant and DNA binding properties. The binding of the compounds with ct-DNA was investigated using absorption spectroscopy and fluorescence quenching. Oxidoreductase, antioxidant enzyme, and DNA targets were used in the molecular docking studies. Compound 2a exhibited good efficacy among Schiff bases in in-vitro antioxidant (71.04 % ± 0.94 DPPH scavenging) and DNA binding (fluorescence quenching, KSV: 2.71 × 10-2 μM-1) studies, as confirmed by molecular docking simulations with oxidoreductase and antioxidant enzymes (Eb: -10.61 and - 5.28 kcal/mol, respectively). Compound Cu(2a)2 showed efficient bioactivity between the complexes in in-vitro antioxidant (DPPH scavenging: 62.81 % ± 1.89) and DNA binding (fluorescence quenching, KSV: 1.3 × 10-2 μM-1) studies, and in molecular docking simulations with antioxidant enzyme and ct-DNA of 1BNA (Eb: -5.23 and - 5.58 kcal/mol, respectively). ADME/T investigations were conducted, establishing a correlation between the biological, electronic, and physicochemical properties of sulfa drug 1, Schiff base 2a, and copper(II) complex Cu(2a)2.