In the ongoing study on polar ingredients of marine organisms, we have isolated six glycolipids (1-6): on the one hand, four glyceroglycolipids - a monogalactolipid, designated as monogalactosyldiacylglycerol MGDG (1), a digalactolipid designated as DGDG (2) and a sulfonoglycolipid diacylated designated as SQDG (3), all three obtained from the red alga Meristotheca senegalensis, and a sulfonoglycolipid monoacylated SGMG (4) from the red alga Caulacanthus ustulatus - and, on the other hand, two sphingoglycolipids - alpha-D-galactopyranosylceramide (5) and beta-D-glucopyranosylceramide (6), obtained from the cnidaria Alcyonium sp. Glycolipids are usually composed of homologues that differ by the length and the terminus (either ethyl or isopropyl) of the alkyl and acyl chains of the non-carbohydrate part of the molecule. We present herein the isolation and the structure elucidation through NMR (H-1, COSY, ROESY) and mass spectrometry (FAB) of glyceroglycolipids (1, 2, 3, 4) and sphingoglycolipids (5, 6). (C) 2004 Publie par Elsevier SAS pour Academie des sciences.
