title: An update on products and mechanisms of lipid peroxidation.
abstract: The free radical reaction of polyunsaturated fatty acids with molecular oxygen leads to hydroperoxides as the first stable products. From linoleic acid the two conjugated diene hydroperoxides at carbons 9 and 13 were considered the only primary products until the recent discovery of the bis-allylic 11-hydroperoxide. The 11-carbon is the site of the initial hydrogen abstraction, and the 11-hydroperoxide is formed without isomerization of the 9,10 and 12,13 cis double bonds. In the autoxidation reaction, bis-allylic hydroperoxides are obtained only in the presence of an efficient antioxidant, for example, alpha-tocopherol. The antioxidant functions as a hydrogen atom donor, necessary to trap the fleeting bis-allylic peroxyl radical intermediate as the hydroperoxide. Understanding of the mechanism of formation of bis-allylic hydroperoxides has led to increased appreciation of the central role of the intermediate peroxyl radical in determining the outcome of lipid peroxidation.
authors.affiliation: Division of Clinical Pharmacology, Department of Pharmacology, Vanderbilt University Medical School, Nashville, TN 37232-6602, USA. claus.schneider@vanderbilt.edu
authors.forename: Claus
authors.initials: C
authors.lastname: Schneider
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry; D007700:Kinetics; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000737:chemistry*; D010545:Peroxides / Q000737:chemistry; D013816:Thermodynamics; D024502:alpha-Tocopherol / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005231:Fatty Acids, Unsaturated; D008054:Lipid Peroxides; D010545:Peroxides; C027369:octadecadienoic acid; C049375:perhydroxyl radical; D024502:alpha-Tocopherol