Exploring Chain-Breaking Antioxidants Profile Dependent at Various pH and co-Antioxidants

Abstract

Understanding towards chain-breaking antioxidants as potent inhibitors of lipid peroxyl radicals, high-throughput efforts have been investigated for antioxidant behaviour of 6-bromo-3,3-dimethyl-8 hexadecyltelluro [1,3]dioxepino[5,6-c]pyridin-9-ol and 2-methyl-2,3-dihydrobenzo[b]selenophene-5-ol in the two phase (chlorobenzene/water) lipid peroxidation model system at various pH 1-7 and mild co-antioxidants such as (glutathione, dithiothreitol, ascorbic acid, sodium ascorbate, and potassium hexacyanoferrate(II) trihydrate, sodium metasulfite, and tris(2-carboxyethyl)phosphine hydrochloride). The key chain-breaking mechanism profile was attributed towards the first oxygen transfer atom from the lipid peroxyl radical to the Se/Te atoms and then hydrogen atom transfer from the nearby phenolic group by the alkoxyl radical due to the weak O-H bond dissociation energy in the solvent cage. Finally, the regeneration could take place by the presence of aqueous soluble co-antioxidants that increased the inhibition time of antioxidants more efficiently than α-tocopherol. Tellurium analouge at pH 2-5 in presence of N-acetylcysteine offered better protection for chain-breaking capacity than the selenium analouge. In the presence of aqueous soluble N-acetylcysteine at pH 1-7, both antioxidants in the present study behaved very good inhibitors of lipid peroxyl radicals.