title: Structure and biosynthesis of novel conjugated polyene fatty acids from the marine green alga Anadyomene stellata.
abstract: Novel polyunsaturated fatty acids with four conjugated double bonds were found in extracts of the green macroalga, Anadyomene stellata. The isolation of five of these with different chain lengths and varying degrees of unsaturation--16:5, 18:4, 20:5, 20:6, and 22:7--was accomplished by organic extraction followed by a combination of vacuum and high-performance liquid chromatography. One of these that was a novel substance (22:7) was characterized as 4Z,7Z,9E,11E,13Z,16Z,19Z-do cosaheptaenoic acid and assigned the trivial name stellaheptaenoic acid. The structure of this new compound, isolated as its methyl ester derivative, was deduced from detailed nuclear magnetic resonance, gas chromatography/mass spectrometry (GC/MS), and other spectroscopic methods. Incubation of a chloroplast preparation, isolated from a crude algal homogenate by differential centrifugation, with six unsaturated fatty acids (palmitoleic, 6Z,9Z,12Z,15Z-octadecatetraenoic acid, arachidonic acid, eicosapentaenoic acid, 7Z,10Z,13Z,16Z-docosatetraenoic acid, and 4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoi c acid) resulted in substantially increased synthesis of unique tetraene compounds as detected by ultraviolet spectrophotometry and tentatively identified by GC/MS.
authors.affiliation: Marine Science Institute, University of California, Santa Barbara 93106, USA.
authors.forename: M V
authors.initials: MV
authors.lastname: Mikhailova
authors.forename: D L
authors.initials: DL
authors.lastname: Bemis
authors.forename: M L
authors.initials: ML
authors.lastname: Wise
authors.forename: W H
authors.initials: WH
authors.lastname: Gerwick
authors.forename: J N
authors.initials: JN
authors.lastname: Norris
authors.forename: R S
authors.initials: RS
authors.lastname: Jacobs
mesh_terms: D000460:Chlorophyta / Q000737:chemistry* / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis* / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011090:Polyenes / Q000737:chemistry*; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005231:Fatty Acids, Unsaturated; D011090:Polyenes