Foefidissimosides C-F, novel glycosides from the roots of Cucurbita foetidissima

Two novel echinocystic acid (=(3β,16α)-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 (24R)/(24S) 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 (3β,16α)-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-β-D-glucopyranosiduronic acid (1), (3β,16α)-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 (3β,gβ,10α,11α,24R)- and (3β,9β,10α, 11α,24S)-25-(β-D-glucopyranosyloxy)-9-methyl-19-norlanost-5-en-3-yl 2-O-β-D-glucopyranosyl-β-D-glucopyranoside (3 and 4, resp.).