title: Arsenic-containing lipids are natural constituents of sashimi tuna.
abstract: Arsenic occurs naturally in many types of seafood as water- and fat-soluble organoarsenic compounds. Although water-soluble compounds have been well characterized, the fat-soluble compounds, so-called arsenolipids, have until recently remained unknown. We report that sashimi-grade tuna fish, with a total arsenic content of 5.9 microg of As/g dry mass, contains approximately equal quantities of water- and fat-soluble arsenic. The water-soluble arsenic comprised predominantly arsenobetaine (>95%) with a trace of dimethylarsinate. Two fat-soluble compounds, which together accounted for about 40% of the lipid-arsenic, were isolated and characterized. The first was identified as 1-dimethylarsinoylpentadecane [(CH(3))(2)As(O)(CH(2))(14)CH(3)] by comparison of HPLC/mass spectrometric data and accurate mass data with those of an authenticated synthesized standard. The second arsenolipid was postulated as 1-dimethylarsinoyl all-cis-4,7,10,13,16,19-docosahexane from mass spectrometric data and analogy with non-arsenic-containing lipids found in fish. The remaining fat-soluble arsenic consisted of less polar arsenolipids of currently unknown structure. This is the first identification of arsenolipids in commonly consumed seafood.
authors.affiliation: Institute of Chemistry, Karl-Franzens University Graz, 8010 Graz, Austria.
authors.forename: Mojtaba S
authors.initials: MS
authors.lastname: Taleshi
authors.forename: John S
authors.initials: JS
authors.lastname: Edmonds
authors.forename: Walter
authors.initials: W
authors.lastname: Goessler
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Ruiz-Chancho
authors.forename: Georg
authors.initials: G
authors.lastname: Raber
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Jensen
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Francesconi
mesh_terms: D000818:Animals; D001151:Arsenic / Q000032:analysis* / Q000737:chemistry*; D001152:Arsenicals / Q000032:analysis / Q000737:chemistry; D002101:Cacodylic Acid / Q000032:analysis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D008055:Lipids / Q000032:analysis* / Q000737:chemistry*; D013058:Mass Spectrometry; D017747:Seafood / Q000032:analysis*; D014413:Tuna
chemical_list: D001152:Arsenicals; D008055:Lipids; D002101:Cacodylic Acid; D001151:Arsenic; C038992:arsenobetaine