Antioxidant activity of novel quinazolinones bearing sulfonamide: Potential radiomodulatory effects on liver tissues via NF-κB/ PON1 pathway

In order to discover new antioxidants, fifteen novel quinazolinone derivatives bearing benzenesulfonamide moiety with variable heterocyclic tail, were synthesized and their structures were established on the basis of spectral data. All the synthesized compounds were screened for their antioxidant potential using DPPH assay in comparison to ascorbic acid. The N-(pyrazin-2-yl)-2-[(4-oxo-3-(4-sulfamoylphenyl)-3,4-dihydroquinazolin-2-yl)thio]acetamide 16 was the most active scaffold in this series with greater scavenging activity than that of ascorbic acid. In vivo acute toxicity study of compound 16 indicates its relative safety with a median lethal dose of 200 mg/kg. The possible antioxidant and hepatoprotective activities of compound 16 were evaluated in irradiated mice. Compound 16 caused mitigation of gamma radiation-induced oxidative stress verified by the decline in MDA, ROS and NF-κB levels. Moreover, SOD and PON1 activities, as well as Zn²⁺ levels, were improved in liver tissues. Furthermore, molecular docking of compound 16 inside the active site of SOD and PON1 demonstrated the same binding interactions as that of the co-crystallized ligands considering the binding possibilities and energy scores. These findings support that compound 16 may represent a structural lead for developing new antioxidants and hepatoprotective agents.