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 FAB‐MS. The new compounds were characterized as 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 ‐[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 ).