A pair of new nortriterpene saponin epimers from the roots of Gypsophila oldhamiana

A pair of new oleanane-type nortriterpene saponin epimers, neogypsoside A (1) and B (2) (F g. 1) with neogypsogenin A (3) and neogypsogenin B (4) as the two new aglycous, as well as the two known triterpene saponins 5 and 6 (Fig. 1), were isolated from the roots of Gypsophila oldhamiana. Their structures were determined by analysis of their NMR data. A possible biogenetic pathway to the nortriterpene saponins 1 and 2 is proposed (Scheme 2).