High-performance liquid chromatography—thermospray mass spectrometry of epoxy polyunsaturated fatty acids and epoxyhydroxy polyunsaturated fatty acids from an incubation mixture of rat tissue homogenate

Naturally occurring monoepoxides of eicosapentaenoic acid and docosahexaenoic acid are bioactive antihyperalgesic lipids

“…These standards CYP enzymes, CYP2J and CYP2C in particular, produce a number of bioactive epoxy-fatty acids ( 10,13 ). Hepatic and renal cytochrome P-450 epoxygenases react equally well with EPA, DHA, and ARA to yield, respectively, multiple epoxyeicosatetraenoic (EpETE), epoxydocosapentaenoic (EpDPE), and epoxyeicosatrienoic (EET) acid regioisomers ( 5,(13)(14)(15)(16)(17). In many cases, the n-3 epoxy-fatty acids demonstrate a similar breadth of activities to the corresponding n-6 fatty acid metabolites although exceptions are likely to exist.…”

“…Several studies established that DHA and EPA can be oxygenated by CYP enzymes in a manner parallel to oxygenation of arachidonic acid ( 5,(14)(15)(16)(17). This prompted us to hypothesize that EpDPEs and EpETEs occur in mammalian tissues.…”

Simultaneous determination by GC‐MS of epoxy and hydroxy FA as their methoxy derivatives

“…The 9,10-dimethoxy C 18 was resolved from the 12,13-dimethoxy and 15,16-dimethoxy C 18 isomers. The 10-methoxy C 19 was partially resolved from the 9,10-dimethoxy C 18 , whereas the 14-methoxy C 19 and the 12,13-dimethoxy C 18 were not resolved. The ions for these coeluting isomers were unique; therefore, each could be determined by MS.…”

“…Epoxy FA have been analyzed directly by GC-MS using less harsh on-column injection techniques (16,17) or by HPLC with MS detection (18). As intermediates in biosynthetic pathways, epoxy FA derived from arachidonic acid have been studied intensively (12,13,(16)(17)(18). The identification of biologically active epoxy FA derived from linoleic acid has increased the interest in these compounds (11).…”

“…Although the mass spectrum gives limited structural information (14,15), the formation of chlorohydrin adducts facilitates the identification of the epoxy group (15). Epoxy FA have been analyzed directly by GC-MS using less harsh on-column injection techniques (16,17) or by HPLC with MS detection (18). As intermediates in biosynthetic pathways, epoxy FA derived from arachidonic acid have been studied intensively (12,13,(16)(17)(18).…”