Partial characterization of a biologically active steroid glycoside isolated from the starfish Marthasterias glacialis

Abstract

1. A steroid glycoside (M₂), which induces avoidance and other reactions in the mollusc Buccinum undatum, has been isolated from extracts of the starfish Marthasterias glacialis by ion-exchange chromatography. 2. The steroid glycoside was homogeneous by t.l.c. and contained glucose, quinovose, fucose and sulphate in the molar proportions 1:2:1:1, in addition to a water-insoluble aglycone. 3. The aglycone was identified as a cholestane derivative containing an unusual Δ²⁴-23-ketone system, two secondary hydroxyl groups and an olefinic double bond, and had the molecular formula C₂₇H₄₂O₃. 4. The rates of release of sugars and sulphate suggested that fucose was at the non-reducing end of the oligosaccharide, with glucose glycosidically linked to the steroid. The sulphate group appeared to be linked to the other hydroxyl group of the steroid.