title: Formation of isoprostane bicyclic endoperoxides from the autoxidation of cholesteryl arachidonate.
abstract: Autoxidation of polyunsaturated fatty acids and esters leads to a complex mixture containing hydroperoxides and cyclic peroxides. Prostaglandin bicyclic endoperoxides have been detected from the autoxidation of cholesteryl arachidonate by LC-MS and GC-MS techniques. All four possible types (I-IV) of bicyclic endoperoxides have been found starting from different regioisomeric hydroperoxides of cholesteryl arachidonate. Furthermore, the stereochemistry of Type IV bicyclic endoperoxides has been determined by conversion to pentafluorobenzyl (PFB) ester, trimethylsilyl (TMS) derivatives, and comparison with synthetic standards by the use of GC-MS. All eight possible diastereomers of the derivatized isoprostanes were observed and were separated by gas chromatography. The bicyclic endoperoxides with the two alkyl chains syn on the cyclopentane ring were formed preferentially to those with anti configuration, a result anticipated from earlier work. Substantial amounts of the anti-substituted isoprostanes, including PGF(2)(alpha), were, however, observed in the product mixture.
authors.affiliation: Department of Chemistry, Medicine and Pharmacology, Center in Molecular Toxicology, Vanderbilt University, Nashville, TN 37235, USA.
authors.forename: Huiyong
authors.initials: H
authors.lastname: Yin
authors.forename: Christine M
authors.initials: CM
authors.lastname: Havrilla
authors.forename: Jason D
authors.initials: JD
authors.lastname: Morrow
authors.forename: Ned A
authors.initials: NA
authors.lastname: Porter
mesh_terms: D001095:Arachidonic Acids; D002788:Cholesterol Esters / Q000737:chemistry* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D028421:Isoprostanes / Q000138:chemical synthesis* / Q000737:chemistry; D015289:Leukotrienes / Q000737:chemistry; D008054:Lipid Peroxides / Q000737:chemistry; D010084:Oxidation-Reduction; D010545:Peroxides / Q000138:chemical synthesis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D001095:Arachidonic Acids; D002788:Cholesterol Esters; D028421:Isoprostanes; D015289:Leukotrienes; D008054:Lipid Peroxides; D010545:Peroxides; C029382:cholesteryl arachidonate; C025086:15-hydroperoxy-5,8,11,13-eicosatetraenoic acid