Structure elucidation and complete NMR spectral assignment of two triterpenoid saponins from Radix Hedysari

A new oleanane-type triterpenoid saponin with a carbonyl group at C-15, named polybosaponin A (1), together with a known triterpenoid saponin, dehydrosoyasaponin I (2), were isolated from Radix Hedysari. On the basis of one- and two-dimensional NMR and high resolution electrospray ionization mass spectrometry, the structure of 1 were elucidated and the (1)H and (13)C NMR spectral signals were assigned totally. In addition, the complete assignment of (1)H NMR signals and revision of incorrect assignment of (13)C NMR signals for 2 were also achieved based on one- and two-dimensional NMR spectrometry.