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-β-D-galactopyranosyl-(1 → 2)-0-[β-D-xylopyranosyl-(1 → 3)β-D-glucuronopyranosyl]quillaic acid 28-[O-β-D-xylopyranosyl-(1 → 3)-O-β-D-xylopyranosyl-(1 →4)-O-α-L-rhamnopyranosyl-(1 → 2)-O-[3,4-di-O-acetyl-β D-quinovopyranosyl-(1 → 4)]-β-D-fucopyranosyl] ester (1), 3-O-[O-β-D-galactopyranosyl-(1 → 2)-O-[β-D-xylopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl]quillaic acid 28-[O-β -D-xylopyranosyl-(1 → 3)-O-β-D-xylopyranosyl-(1 → 4)-O-α-L-rhamnopyranosyl-(1 → 2)-O-[4-O-acetyl-β -D-quinovopyranosyl-(1 → 4)]-β-D-fucopyranosyl] ester (2), 3-O-[O-β-D-galactopyranosyl-(1→2)-O-[β-D-xylopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl]quillaic acid 28-[O-β-D-xylopyranosyl-(1 → 4)-O-α-L-rhamnopyranosyl-(1 → 2)-O-[4-O-acetyl-β -D-quinovopyranosyl-(1 → 4)]-β-D-fucopyranosyl] ester (3), and gypsogenic acid 28-[O-β-D-glucopyranosyl-(1 → 2)-O-β -D-glucopyranosyl-(1 → 6)-O-β-D-glucopyranosyl-(1 → 3)-β-D-galactopyranosyl] ester (4).