Junceosides A-C, new triterpene saponins from Arenaria juncea

Three novel triterpenoid saponins, junceosides A (1), B (2), and C (3), together with two known saponins have been isolated from the roots of Arenaria juncea. Their structures were elucidated using a combination of homo- and heteronuclear 2D NMR techniques (COSY, TOCSY, NOESY, HSQC, and HMBC) and by FAMBS. The new compounds were characterized as 3-O-α-L-arabinopyranosyl-(1→2)-[β-D-galactopyranosyl- (1→3)]-β-D-glucoronopyranosylgypsogenin-28-O-β- D-glucopyranosyl(1→3)-[β-D-xylopyranosyl- (1→4)]-α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranoside (1), 3-O-α-L-arabinopyranosyl-(1→2)- [β-D-galactopyranosyl- (1→3]-β-D-glucoronopyranosylgypsogenin- 28-O-β-D-xylopyranosyl-(1→3)-β-D-xylopyranosyl- (1→4)-α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranoside (2), and 3-O-β-D-xylopyranosyl-(1→3)-[β-D-galactopyranosyl- (1→2)]-β-D-glucoronopyranosylgypsogenin-28-O-β- D-xylopyranosyl-(1→4)]-α-L-rhamnopyranosyl- (1→2)-β-D-fucopyranoside.