title: Identification of the oleic acid ethanolamide (OEA) isomer cis-vaccenic acid ethanolamide (VEA) as a highly abundant 18:1 fatty acid ethanolamide in blood plasma from rats and humans.
abstract: The endocannabinoid system is important in various physiological pathways, especially the regulation of food intake. It consists of endocannabinoids like 2-arachidonoyl-glycerol (2-AG) or the fatty acid ethanolamide archachidonoyl-ethanolamide (AEA) with binding affinity to cannabinoid receptors. Further, fatty acid ethanolamides (FAEAs) influence the endocannabinoid system without affecting cannabinoid receptors by using independent physiological pathways. Among FAEAs, oleic acid ethanolamide (OEA) gained importance because of its promising ability to reduce food intake. By ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS), we detected a chromatographically separated molecule in plasma samples from rats and humans with identical mass and fragmentation patterns as those of OEA. Via synthesis and extensive analysis of ethanolamides of different cis/trans- and position isomers of oleic acid (cis9-18:1), we could identify the unknown molecule as vaccenic acid (cis11-18:1) ethanolamide (VEA). In this study we identified VEA as the most abundant 18:1 FAEA in rat plasma and the second most abundant 18:1 FAEA in human plasma.
authors.affiliation: Food Chemistry Unit, Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Schuhstr. 19, 91052, Erlangen, Germany.
authors.forename: Waldemar
authors.initials: W
authors.lastname: Röhrig
authors.affiliation: Medicinal Chemistry Unit, Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Schuhstr. 19, 91052, Erlangen, Germany.
authors.forename: Reiner
authors.initials: R
authors.lastname: Waibel
authors.affiliation: Food Chemistry Unit, Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Schuhstr. 19, 91052, Erlangen, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Perlwitz
authors.affiliation: Food Chemistry Unit, Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Schuhstr. 19, 91052, Erlangen, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Pischetsrieder
authors.affiliation: Food Chemistry Unit, Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Schuhstr. 19, 91052, Erlangen, Germany. foodchem@fau.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Hoch
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D063388:Endocannabinoids / Q000032:analysis / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D007536:Isomerism; D008297:Male; D009829:Oleic Acids / Q000032:analysis / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D063388:Endocannabinoids; D009829:Oleic Acids; C488250:oleoylethanolamide; C065593:cis-vaccenic acid
keywords: Endocannabinoid system; Fatty acid ethanolamides; LC–MS/MS; OEA; VEA