Biologically active glycosides from asteroidea, XIX. Glycosphingolipids from the starfish <i>Acanthaster planci</i> 4. Isolation and structure of five new gangliosides

Abstract

Abstract Five new gangliosides — acanthaganglioside A ( 1 ), B ( 2 ), C ( 3 ), D ( 4 ) and E ( 5 ) — were purified from the water‐soluble lipid fraction of the chloroform/methanol extract of the starfish Acanthaster planci. Based on chemical and spectroscopic data, the structures of 1 – 5 were elucidated. The gangliosides consist of one homogeneous long‐chain base, five or six sugars and different fatty acids. Reversed‐phase HPLC using methanol/ammonia/water as solvent was effective in isolating these gangliosides, showing the very close similarity in their structures. Negative FAB mass spectrometry provided important information both on the structure of the sugar moiety and on the molecular mass of the gangliosides. Partial hydrolysis by hot pyridine/water or hot water was useful for structure elucidation of the complex oligosaccharide moieties.