Saponarioside C, the first alpha-D-galactose containing triterpenoid saponin, and five related compounds from Saponaria officinalis

Six novel triterpenoid saponins, named saponariosides C-H, were isolated from the whole plants of Saponaria officinalis. Their structures were established as saponarioside C (1), 3-O-beta-D-xylopyranosyl-gypsogenic acid-28-O-alpha-D-galactopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-- >6)-beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranoside; saponarioside D (2), 3-O-beta-D-xylopyranosyl-gypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->6) -beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranoside; saponarioside E (3), 3-O-beta-D-glucopyranosyl-gypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->6) -beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranoside; saponarioside F (4), 3-O-beta-D-xylopyranosyl-16alpha-hydroxygypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->6) -beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranoside; saponarioside G (5), 3-O-beta-D-xylopyranosyl-16alpha-hydroxygypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->3 )]-beta-D-glucopyranoside; and saponarioside H (6), 3-O-beta-D-xylopyranosyl-gypsogenic acid-28-O-beta-D-glucopyranoside, by a combination of extensive NMR (DEPT, COSY, HOHAHA, HETCOR, HMBC, and NOESY) studies and chemical degradation.