New acylated triterpene saponins from Polygala tenuifolia willd

Abstract

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-(β-d-glucopyranosyl) presenegenin 28-{O-β-d-apiofuranosyl-(1 → 3)-O-[β-d-xylopyranosyl-(1 → 4)]-O-α-l-rhamnopyranosyl-(1 → 2)-O-[α-l-rhamnopyranosyl-(1 → 3)]-4-O-[(E)-p-methoxycinnamoyl]-β-d-fucopyranosyl} ester (5) and its (Z)-isomer (6).

Keywords:

• Polygala tenuifolia
• Triterpene saponin
• E-Onjisaponin H
• Z-Onjisaponin H