摘要:
Three steroidal constituents having the rare cis-B/C ring junctions (8-alpha-OH, 9-alpha-H), named amalogenin A, amaloside A and amaloside B, were isolated from the vine of Amalocalyx yunnanesis. The structures were deduced by precise NMR studies and confirmed by X-ray diffraction for amaloside A. The structures were shown to be 3-beta,8-alpha-dihydroxy-8-alpha,9-alpha,14-beta,17-beta,20(R)-pregn-5-ene-14,20-epoxy-13-carboxylic-20-lactone (amalogenin A) amalogenin A 3-O-beta-D-diginopyranoside (amaloside A) and amalogenin A 3-O-beta-D-glucopyranosyl(1-4)-beta-D-diginopyranoside (amaloside B).