Cucurbitane and hexanorcucurbitane glycosides from the fruits of Cucurbita pepo cv dayangua

Phytochemical investigation of the fruits of Cucurbita pepo cv dayangua has led to the isolation of two cucurbitane glycosides: cucurbitacin L 2-O-beta-D-glucopyranoside (1), cucurbitacin K 2-O-beta-D-glucopyranoside (2) and two hexanorcucurbitane glycosides: 2,16-dihydroxy-22,23,24,25,26,27-hexanorcucurbit-5-en-11,20-dione 2-O-beta-D-glucopyranoside (3) and 16-hydroxy-22,23,24,25,26,27-hexanorcucurbit-5-en-11,20-dione 3-O-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranoside (4). Compounds 1, 2 and 3 were isolated from Cucurbita genus for the first time, while compound 4 is a new one. Their structures were determined on the basis of chemical and spectroscopic evidence.