Amphiceramide A and B, Novel Glycosphingolipids from the Marine Sponge Amphimedon compressa

Glycolipid analysis of the Caribbean sponge Amphimedon compressa has shown it to contain two novel glycosphingolipids, amphiceramide A (1a) and B (2a), which possess an unusual Δ6‐phytosphingosine. The saccharide chain of amphiceramide A is composed of a β‐glucose residue glycosylated at the 6‐position by an N‐acetyl‐β‐glucosamine and has never been found before in a natural product. The saccharide chain of amphiceramide B consists of an allolactose [Gal(1β→6)Glc] residue β‐linked to the ceramide and is found here for the first time in a natural glycosphingolipid. In addition, the sponge contains a new molecular species, acetamidoglucosyl ceramide (3a), and the known glucosyl ceramide 4a (halicerebroside A) and melibiosyl ceramide 5a (amphimelibioside C). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)