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

Abstract

Phytochemical investigation of the fruits of Cucurbita pepo cv dayangua has led to the isolation of two cucurbitane glycosides: cucurbitacin L 2-O-β-d-glucopyranoside (1), cucurbitacin K 2-O-β-d-glucopyranoside (2) and two hexanorcucurbitane glycosides: 2,16-dihydroxy-22,23,24,25,26,27-hexanorcucurbit-5-en-11,20-dione 2-O-β-d-glucopyranoside (3) and 16-hydroxy-22,23,24,25,26,27-hexanorcucurbit-5-en-11,20-dione 3-O-α-l-rhamnopyranosyl-(1 → 2)-β-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.

Keywords:

• Cucurbita pepo cv dayangua
• Cucurbitane glycoside
• Hexanorcucurbitane glycoside
• Cucurbita

Acknowledgements

The authors are grateful to A. Zeper for mass spectra measurement, and Wen Li and Yi Sha for NMR measurement. Financial support is from the National Natural Science Foundation of China (No. 30371083).