Saponin and Sapogenol. XXVI. Steroidal Saponins from the Starfish Acanthaster planci L. (Crown of Thorns). (2). Structure of the Major Saponin Thornasteroside A

Abstract

The major saponin named thornasteroside A (5) has been isolated from the whole body of starfish A canthaster planci L. (crown of thorns). In order to facilitate the structural study, thornasteroside A (5) has been converted to a pentaglycoside (designated as dsp-1), which corresponds to a desulfated pregnane-type derivative of 5. On the bases of chemical reactions and physicochemical evidence, the structure of dsp-1 has been elucidated as 10. Based on the accumulated evidence in this and the preceding papers, the structure of thornasteroside A has been established as 20-hydroxy-6α-O-{β-D-fucopyranosyl(l—>2)-β-D-galactopyranosyl(l—>4)-[β-d -quinovopyranosyl(l—>2)]-β-D- xylopyranosyl(l—>3)-β-d-quinovopyranosyl}-5α-cholest-9(ll)-en-23-on-3β-yl sodium sulfate (5). © 1978, The Pharmaceutical Society of Japan. All rights reserved.