Biologically active glycosides from asteroidea, XIII. Glycosphingolipids from the starfish Acanthaster planci, 2. Isolation and structure of six new cerebrosides

Six new cerebrosides (ceramide monohexosides), acanthacerebroside A (1), B (2), C (3), D (4), E (5), and F (6) were isolated from the water‐insoluble lipid fraction of the chloroform‐methanol extract of the starfish Acanthaster planci. On the basis of chemical and spectral evidences, they were characterized as 1‐O‐(β‐D‐glucopyranosyl)‐substituted (1S,3S,4R)‐2‐[(2R)‐2‐hydroxytetracosanoylamino]‐1,3,4‐hexadecanetriol (1), (2S,3S,4R)‐2‐[(2R)‐2‐hydroxyhexadecanoylamino]‐1,3,4‐docosanetriol (2), (2S,3S,4R,13E)‐2‐[(2R)‐2‐hydroxyhexadecanoylamino]‐13‐docosene‐1,3,4‐triol (3), (2S,3R,4E,10E)‐2‐[(2R)‐2‐hydroxydocosanoylamino]‐4,10‐octadecadiene‐1,3‐diol (4), (2S,3R,4E,10E)‐2‐[(2R)‐2‐hydroxydocosanoylamino]‐4,10‐octadecadiene‐1,3‐diol (5), and (2S,3R,4E,10E)‐2‐[(2R)‐2‐hydroxytetracosanoylamino]‐4,10‐octadecadiene‐1,3‐diol (6). Reversed‐phase HPLC was effective to isolate these cerebrosides revealing the very close resemblance in structure. Negative FABMS spectrometry was useful in providing information on the molecular mass of the cerebrosides.