CAT and gastric ulcer: Regarding quercetin, the most potent antioxidant flavonoid, studies demonstrated that it has a beneficial effect in attenuating indomethacin-induced gastric ulcers in rats by increasing the antioxidants enzymes activity (Catalase, SOD, and GPX).91,94 The mechanisms behind the antioxidant activity are scavenging oxygen radicals, protecting against lipid peroxidation, and chelating metal ions.115–119