Tautomerism and antioxidant power of sulfur-benzo[h]quinoline: DFT and molecular docking studies

Abstract

In this work, a systematic quantum chemical investigation of antiradical activity of sulfur-benzo[h]quinolone was performed in physiological environments. DFT analysis revealed that sulfur-benzo[h]quinolone exhibits strongly solvent-dependent tautomerism. The reactions of the tautomeric and different acid-base species toward hydroperoxyl (HOO) radical were considered following the formal hydrogen atom transfer (FHT) mechanism and the single electron transfer (SET) mechanism. It was found that the antioxidant activity of NH form in lipid medium is higher than that of the reference antioxidants Trolox and ascorbic acid with the rate constant k = 3.2 × 105 M−1s−1. Molecular docking analysis illustrated that sulfur-benzo[h]quinolone is also a potential inhibitor of the pro-oxidant action of cytochrome P450, myeloperoxidase, NADPH oxidase, and xanthine oxidase enzymes.