Biologically active glycosides from asteroidea, III. Steroid oligoglycosides from the starfish Acanthaster planci L., 2. Structures of two newly characterized genuine sapogenins and an oligoglycoside sulfate

Abstract

AbstractFrom the whole bodies of Acanthaster planci L. a genuine oligoglycoside which is an unstable type 20‐hydroxycholesten‐23‐one glycoside sulfate has been isolated in large quantities. Apart from the known 3β,6α‐dihydroxy‐5α‐pregn‐9(11)‐en‐20‐one (1) two new genuine aglycones were isolated by enzymatic hydrolysis of the crude oligoglycoside fraction for the first time. The structures were identified by chemical and spectroscopic evidence to be 3β,6α,20ζ‐trihydroxy‐5α‐cholest‐9(11)en‐23‐one (2) and 3β,6α,20ξ‐trihydroxy‐5α‐cholesta‐9(11),24‐dien‐23‐one (3), respectively. The structure of the newly characterized pentaglycoside sulfate Acanthaglycoside A was then determined to be 3β‐sodiosulfonatooxy‐6α,20ξ‐dihydroxy‐23‐oxo‐5α‐cholesta‐9(11),24‐dien‐6α‐ylO‐β‐D‐fucopyranosyl‐(1→2)‐O‐β‐D‐quinovopyranosyl‐(1→4)‐O‐[β‐D‐quinovopyranosyl‐(1→2)]‐O‐β‐D‐xylopyranosyl‐(1→3)‐O‐β‐D‐quinovopyranoside (4). Apart from conventional analytical methods, fast atom bombardment mass spectrometry (FAB‐MS) was successfully used for the first time for determination and confirmation of the structure of the natural oligoglycoside sulfate.