Starfish saponins. 48. Isolation of fifteen sterol constituents (six glycosides and nine polyhydroxysteroids) from the starfish Solaster borealis

A complete steroid glycoside and polyhydroxysteroid anal. of the starfish S. borealis, collected at Mutsu Bay, Japan, is reported. The glycosides include a new pentaglycoside steroid sulfate (asterosaponin), designated solasteroside A (I), 2 new sulfated 24-O-diglycosides, both with the common 5α-cholesta-3β,6α,8,15α,24-pentaol aglycon, borealosides A (II) and B (III), 2 new 24-O-(3-O-methyl)xylosides, borealosides C (IV) and D (V), having the same aglycon with an addnl. hydroxy group at 4β-position in V, and the known amurenoside B, previously isolated from Asterias amurensis. Among the polyhydroxysteroid constituents, 4 are new, and 5 have previously been isolated from starfishes.