Gleditsiosides N-Q, new triterpenoid saponins from Gleditsia sinensis

The structures of gleditsiosides N, O, P, and Q (1-4), isolated from anomal ous fruits of Gleditsia sinensis, were characterized as novel complex bisde smosidic triterpenoid glycosides acylated with monoterpenoid units, by mean s of extensive 1D and 2D NMR studies. The four compounds shared a common st ructural feature with a trisaccharide [(beta-D-xylopyranosyl-(1 --> 2)-alph a-L-arabinopyranosyl-(1 --> 6)-beta-D-glucopyranoside)] affixed to C-3 and a tetrasaccharide [(beta-D-xylopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl ester)] atta ched to C-28. Gleditsioside P (3) is the first saponin of this type found t o date bearing three monoterpenoid units.