New acylated triterpene saponins from Polygala tenuifolia willd.

Two new acylated presenegenin glycosides E-onjisaponin H (5) and Z-onjisaponin (6) together with seven known saponins were isolated from the roots of Polygala tenuifolia Willd. Compounds 5 and 6 were obtained as a pair of isomers due to trans and cis-p-methoxycinnamoyl. Their structures were elucidated mainly by 2D-NMR techniques including 1H-1HCOSY, TOCSY, HSQC, HMBC as 3-O-(beta-D-glucopyranosyl) presenegenin 28-[O-beta-D-apiofuranosyl-(1 --> 3)-O-[beta-D-xylopyranosyl-(1 --> 4)]-O-alpha-L-rhamnopyranosyl-(1 --> 2)-O-[alpha-L-rhamnopyranosyl-(1 --> 3)]-4-O-[(E)-p-methoxycinnamoyl]-beta-D-fucopyranosyl] ester (5) and its (Z)-isomer (6).