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 fr om the whole plants of Saponaria officinalis. Their structures were establi shed 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-gluc opyranosyl-(1-->3)]-beta-D-glucopyranoside; saponarioside D (2), 3-O-beta-D -xylopyranosyl-gypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->2)-beta-D-gl ucopyranosyl-(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-glucopyranos yl-(1-->3)]-beta-D-glucopyranoside; saponarioside F (4), 3-O-beta-D-xylopyr anosyl-16 alpha-hydroxygypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->2)-b eta-D-glucopyranosyl-(1-->6)-[beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopy ranoside; saponarioside G (5), 3-O-beta-D-xylopyranosyl-16 alpha-hydroxygyp sogenic acid-28-O-beta-D-glucopyranosyl-(1-->6)-[beta-D-glucopyranosyl-(1-- >3)]-beta-D-glucopyranoside; and saponarioside H (6), 3-O-beta-D-xylopyrano syl gypsogenic acid-28-O-beta-D-glucopyranoside, by a combination of extens ive NMR (DEPT, COSY, HOHAHA, HETCOR, HMBC, and NOESY) studies and chemical degradation.