Structural Analysis of the Minor Cerebrosides from a Glass Sponge Aulosaccus sp.

Abstract
The minor cerebrosides from a Far-Eastern glass sponge Aulosaccus sp. were analyzed as constituents of some multi-component RP-HPLC fractions. The structures of eighteen new and one known cerebrosides were elucidated on the basis of NMR spectroscopy, mass spectrometry, optical rotation data and chemical transformations. These β-D-glucopyranosyl-(1→1)-ceramides contain sphingoid bases N-acylated with straight-chain (2R)-2-hydroxy fatty acids, namely, (2S,3S,4R,11Z)-2-aminoeicos-11-ene-1,3,4-triol, acylated with 15E-22:1, 16Z-21:1, 15Z-21:1, 15Z-20:1, 15E-20:1, 19:0, 18:0 acids, (2S,3S,4R)-2-amino-13-methyltetradecane-1,3,4-triol—with 19Z-26:1, 16Z-23:1, 23:0, 22:0 acids, (2S,3S,4R)-2-amino-14-methylpentadecane-1,3,4-triol—with 16Z-23:1, 16E-23:1, 15Z-22:1, 22:0 acids, (2S,3S,4R)-2-amino-14-methylhexadecane-1,3,4-triol, linked to 16Z-23:1, 15Z-22:1 acids, (2S,3S,4R)-2-amino-9-methylhexadecane-1,3,4-triol—to 16Z-23:1 acid, and (2S,3S,4R)-2-aminohexadecane-1,3,4-triol, attached to 15Z-22:1 acid. The 13-methyl and 9-methyl-branched trihydroxy sphingoid base backbones (C15 and C17, respectively) have not been found previously in sphingolipids. The ceramide parts, containing other backbones, present new variants of N-acylation of the marine sphingoid bases with the 2-hydroxy fatty acids. The combination of the instrumental and chemical methods used in this study improved the efficiency of the structural analysis of such complex cerebroside mixture...

Source: Lipids - October 16, 2015 Category: Lipidology Source Type: research