Foetidissimosides C–F, Novel Glycosides from the Roots of Cucurbita foetidissima

Two novel echinocystic acid (=(3 β ,16 α )‐3,16‐dihydroxyolean‐12‐en‐28‐oic acid) glycosides, foetidissimosides C ( 1 ), and D ( 2 ), along with new cucurbitane glycosides, i.e. , foetidissimosides E/F ( 3 / 4 ) as an 1 : 1 mixture of the (24 R )/(24 S ) epimers, were obtained from the roots of Cucurbita foetidissima. Their structures were elucidated by means of a combination of homo‐ and heteronuclear 2D‐NMR techniques (COSY, TOCSY, NOESY, ROESY, HSQC, and HMBC), and by FAB‐MS. The new compounds were characterized as (3 β ,16 α )‐28‐{[ O ‐ β ‐ D ‐glucopyranosyl‐(1→3)‐ O ‐ β‐ D ‐xylopyranosyl‐(1→4)‐ O ‐6‐deoxy‐ α ‐ L ‐mannopyranosyl‐(1→2)‐ α ‐ L ‐arabinopyranosyl]oxy}‐16‐hydroxy‐28‐oxoolean ‐12‐en‐3‐yl β ‐ D ‐glucopyranosiduronic acid ( 1 ), (3 β ,16 α )‐16‐hydroxy‐28‐oxo‐28‐{{ O ‐ β ‐ D ‐xylopyranosyl‐(1→3)‐ O ‐[ β‐ D ‐xylopyranosyl‐(1→4)]‐ O ‐6‐deoxy‐ α ‐ L ‐mannopyranosyl‐(1→2)‐ α ‐ L ‐arabinopyranosyl}oxy}olean‐12‐en‐3‐yl β ‐ D ‐glucopyranosiduronic acid ( 2 ), and (3 β ,9 β ,10 α ,11 α ,24 R )‐ and (3 β ,9 β ,10 α ,11 α ,24 S )‐25‐( β ‐ D ‐glucopyranosyloxy)‐9‐methyl‐19‐norlanost‐5‐en‐3‐yl 2‐ O ‐ β ‐ D ‐glucopyranosyl‐ β ‐ D ‐glucopyranoside ( 3 and 4 , resp.).