New triterpene saponins from Acanthophyllum pachystegium

Four new triterpenoid saponins, pachystegiosides A (1), B (2), C (3), and D (4), were isolated from the roots of Acanthophyllum pachystegium K. H. Their structures were elucidated by means of a combination of homo- and heteronuclear 2D-NMR techniques (COSY, TOCSY, NOESY, HSQC, and HMBC) and by FABMS. The new compounds were characterized as 3-O-(O-beta-D-galactopyranosyl-(1 --> 2)-O-[beta-D-xylopyranosyl(1 --> 3)]-beta-D-glucuronopyranosyl)quillaic acid 28-(O-beta-D-xylopyranosyl-(1 --> 3)-O-beta-D-xylopyranosyI-(1 --> 4)O-alpha-L-rhamnopyranosyl-(1 --> 2)-O-[3,4-di-O-acetyl-beta-D-quinovopyranosyl-(1 --> 4)]-beta-D-fucopyranosyl)ester (1). 3-O-(O-beta-D-galactopyranosyl-(1 --> 2)-O-[beta-D-xylopyranosyI-(1 --> 3)]-beta-D-glucuronopyranosyl)quillaic acid 28-(O-beta-D-xylopyranosyl-(1 --> 3)-O-beta-D-xylopyranosyl-(1 --> 4)-O-alpha-L-rhamnopyranosyl-(1 --> 2)-O-[4-O-acetyl-beta-D-quinovopyranosyl-(1 --> 4)]-beta-D-fucopyranosyl) ester (2), 3-O-(O-beta-D-galactopyranosyl-(1 --> 2)-O-[beta-D-xylopyranosyl-(1 --> 3)]-beta-D-glucuronopyranosyl)quillaic acid 28-(O-beta-D-xylopyranosyl-(1 --> 4)-O-alpha-L-rhamnopyranosyl-(1 --> 2)-O-[4-O-acetyl-beta-D-quinovopyranosyl-(I --> 4)]-beta-D-fucopyranosyl) ester (3), and gypsogenic acid 28-[O-beta-D-glueopyranosyl-(1 --> 2)-O-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-galactopyranosyl] ester (4).