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Antioxidant action of a lipophilic nitroxyl radical, cyclohexane‐1‐spiro‐2′‐(4′‐oxyimidazolidine‐1′‐oxyl)‐5′‐spiro‐1″‐cyclohexane, against lipid peroxidation under hypoxic conditions
Author(s) -
Shimakawa Shuichi,
Yoshida Yasukazu,
Niki Etsuo
Publication year - 2003
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-003-1055-3
Subject(s) - nitroxyl , chemistry , ascorbic acid , antioxidant , lipid peroxidation , radical , organic chemistry , medicinal chemistry , photochemistry , food science
Nitroxyl radicals are known to act as radical scavenging antioxidants. In the present study, a lipophilic nitroxyl radical, cyclohexane‐1‐spiro‐2′‐(4′‐oxyimidazolidine‐1′‐oxyl)‐5′‐spiro‐1″‐cyclohexane (nitroxyl radical I) was synthesized and its antioxidant capacity was assessed in comparison with a hydrophilic nitroxyl radical, 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐ N ‐oxyl (Tempol). Both nitroxyl radical I and Tempol inhibited methyl linoleate oxidation induced by free radicals, and the efficacy increased with decreasing partial pressure of oxygen, the effect being more pronounced for nitroxyl radical I than Tempol. Their hydroxylamines inhibited lipid peroxidation more effectively than their corresponding parent nitroxyl radicals. In liposomal membranes, a synergistic effect was observed in the combination of nitroxyl radical I with ascorbic acid, whereas only an additive effect was observed between Tempol and ascorbic acid. The present study suggests that nitroxyl radical I and its hydroxylamine may act as potent antioxidants, especially in combination with ascorbic acid under hypoxic conditions.