title: Arachidonate geometrical isomers generated by thiyl radicals: the relationship with trans lipids detected in biological samples.
abstract: The presence of trans fatty acids in mammalians is attributed to exogenous sources; nevertheless, trans isomers could be easily formed by free radical-catalyzed isomerization processes in vivo. The isomerization of methyl arachidonate (all-cis isomer) catalyzed by thiyl radical is proposed as a methodology applicable in biochemical laboratories, which produces mono- and di-trans isomers. Carbon-13 nuclear magnetic resonance spectroscopy shows that the carbon atom in position 15 is characteristic for each mono- and di-trans isomer. Antioxidants, such as alpha-tocopherol and all-trans-retinol acetate, inhibited the isomerization process. Trans phospholipids are formed in erythrocyte membranes by exposing blood to gamma-irradiation in the presence of thiols, which is in contradiction with the known role of these compounds as radioprotectors. Trans isomers are also analyzed in tissues harvested from breast cancer patients and compared to the adipose breast tissue taken a few centimeters from the edge of the tumor from the same patient. This work is generally aimed at contributing to the debate on trans fatty acids and stimulating a reconsideration of the current view on the exclusive presence of cis double bonds in cell membranes by studying radical processes that could affect or protect this natural configuration.
authors.affiliation: ISOF, Consiglio Nazionale delle Ricerche, Bologna, Italy. cferreri@area.bo.cnr.it
authors.forename: Carla
authors.initials: C
authors.lastname: Ferreri
authors.forename: M Rosaria
authors.initials: MR
authors.lastname: Faraone Mennella
authors.forename: Cesare
authors.initials: C
authors.lastname: Formisano
authors.forename: Laura
authors.initials: L
authors.lastname: Landi
authors.forename: Chryssostomos
authors.initials: C
authors.lastname: Chatgilialoglu
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D016718:Arachidonic Acid / Q000737:chemistry* / Q000378:metabolism; D001943:Breast Neoplasms / Q000473:pathology; D002244:Carbon / Q000737:chemistry; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D004307:Dose-Response Relationship, Radiation; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D005609:Free Radicals; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D008956:Models, Chemical; D020033:Protein Isoforms; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013997:Time Factors
chemical_list: D005227:Fatty Acids; D005609:Free Radicals; D008055:Lipids; D020033:Protein Isoforms; D013438:Sulfhydryl Compounds; D016718:Arachidonic Acid; D002244:Carbon