Biologically active glycosides from asteroidea, XXVIII. Glycosphingolipids from the starfish Asterias amurensis versicolor Sladen, 1. Isolation and structure of six new cerebrosides, asteriacerebrosides AF, and two known cerebrosides, astrocerebroside A and acanthacerebroside C

Six new cerebrosides, asteriacerebroside A ( 1 ), B ( 2 ), C ( 3 ), D ( 4 ), E ( 7 ) and F ( 8 ), have been isolated from the two cerebroside molecular species obtained from the less polar fraction of the chloroform/methanol extract of the starfish Asterias amurensis versicolor Sladen. The structures of these cerebrosides have been determined on the basis of chemical and spectroscopic evidences. Two known cerebrosides, astrocerebroside A ( 5 ) and acanthacerebroside C ( 6 ), have also been isolated and characterized. Reversed‐ and normal‐phase HPLC were effective in isolating these cerebrosides, showing the very close similarity in their structures. Mass spectrometry of dimethyl disulfide derivatives of the cerebrosides was useful for the determination of the double‐bond position in the cerebrosides.