Gleditsiosides N-Q, new triterpenoid saponins from Gleditsia sinensis

The structures of gleditsiosides N, O, P, and Q (1-4), isolated from anomalous fruits of Gleditsia sinensis, were characterized as novel complex bisdesmosidic triterpenoid glycosides acylated with monoterpenoid units, by means of extensive 1D and 2D NMR studies. The four compounds shared a common structural feature with a trisaccharide [(beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-be ta- D-glucopyranoside)] affixed to C-3 and a tetrasaccharide [(beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L-r hamnopyranosyl-(1-->2)-beta-D-glucopyranosyl ester)] attached to C-28. Gleditsioside P (3) is the first saponin of this type found to date bearing three monoterpenoid units.