Isolation of the Molecular Species of Monogalactosyldiacylglycerols from Brown Edible Seaweed Sargassum horneri and Their Inhibitory Effects on Triglyceride Accumulation in 3T3-L1 Adipocytes

The chemical composition of monogalactosyldiacylglycerols (MGDGs) from brown alga Sargassum homeri and their inhibitory effects on lipid accumulation were investigated in this study. A total of 10 molecular species of MGDGs were identified using nuclear magnetic resonance, alkaline hydrolysis, gas chromatography flame ionization detector, and high-performance liquid chromatography tandem mass spectrometry methods. Individual molecular species of MGDGs, including (2S)-1-O-myristoyl-2-O-palmitoleoyl-3-O-beta-D-galactopyranosyl-sn-glycerol (1), (2S)-1-O-myristoyl-2-O-linoleyl-3-O-beta-D-galactopyranosyl-sn-glycerol (3), (2S)-1-O-palmitoyl-2-O-linolenoyl-3-O-beta-D-galactopyranosyl-sn-glycerol (5), (2S)-1-O-myristoyl-2-O-oleyl-3-O-beta-D-galactopyranosyl-sn-glycerol (7), (2S)-1-O-palmitoyl-2-O-palmitoleoyl-3-O-beta-D-galactopyranosyl-sn-glycerol (8), (25)-1-O-palmitoyl-2-O-linoleyl-3-O-beta-D-galactopyranosyl-sn-glycerol (9), and (2S)-1-O-palmitoyl-2-O-oleyl-3-O-beta-D-galactopyranosyl-sn-glycerol (10), were then furnished using semi-preparative high-performance liquid chromatography, and their inhibitory effects on triglyceride (TG) accumulation and free fatty acid (FFA) levels in 3T3-L1 adipocytes were evaluated. Compounds 3 and 9 showed inhibitory effects on TG and FFA accumulation, with TG levels of 1.568 +/- 0.2808 and 1.701 +/- 0.1460 mu mol/L and FFA levels of 0.149 +/- 0.0258 and 0.198 +/- 0.0229 mequiv/L, respectively, which were more effective than other compounds. The primary structure activity relationship suggested that linoleyl [18:2(omega-6)] in the sn-2 position played an important role on triglyceride accumulation inhibition.