title: Two new monogalactosyl diacylglycerols from brown alga Sargassum thunbergii.
abstract: Two new monogalactosyl diacylglycerols (MGDGs) along with two known glycolipids were isolated from the moderate polar fraction of the methanolic extract of the brown alga Sargassum thunbergii by using reversed silica flash chromatography. Two new MGDGs were identified as (2S)-1-O-(5Z,8Z,11Z,14Z,17Z-eicosapentaenoyl)-2-O-(9Z,12Z,15Z-octadecatrienoyl)-3-O-beta-D-galactopyranosyl-sn-glycerol (1) and (2S)-1-O-(9Z,12Z,15Z-octadecatrienoyl)-2-O-(6Z,9Z,12Z,15Z-octadecatetraenoyl)-3-O-beta-D-galactopyranosyl-sn-glycerol (2) by FAB tandem mass spectrometry, NMR techniques, and specific enzyme-catalyzed hydrolysis of the sn-1 fatty acyl linkage. The regiochemical attachment of the acyl chains in the glycerol moiety was established by 2D NMR correlations and confirmed by enzymatic hydrolysis.
authors.affiliation: Proteomics Team, Korea Basic Science Institute, 52 Eoun-Dong Yuseong-Gu, Daejeon, 305-333, South Korea.
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Kim
authors.forename: Eun-Hee
authors.initials: EH
authors.lastname: Kim
authors.forename: Chulhyun
authors.initials: C
authors.lastname: Lee
authors.forename: Mi-Hee
authors.initials: MH
authors.lastname: Kim
authors.forename: Jung-Rae
authors.initials: JR
authors.lastname: Rho
mesh_terms: D038983:Galactolipids / Q000032:analysis* / Q000737:chemistry* / Q000302:isolation & purification; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015394:Molecular Structure; D044647:Sargassum / Q000737:chemistry*; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: C523010:1-O-(5,8,11,14,17-eicosapentaenoyl)-2-O-(9,12,15-octadecatrienoyl)-3-O-galactopyranosyl-sn-glycerol; C523011:1-O-(9,12,15-octadecatrienoyl)-2-(6,9,12,15-octadecatetraenoyl)-3-O-galactopyranosyl-sn-glycerol; D038983:Galactolipids; C009909:monogalactosyldiacylglycerol