Euphopubescenol and euphopubescene, two new jatrophane polyesters, and lathyrane-type diterpenes from Euphorbia pubescens.

ABSTRACT

The structures of euphopubescenol and euphopubescene, two new macrocyclic jatrophane diterpene polyesters, isolated from the whole dried plant of Euphorbia pubescens, were established as 5alpha,8alpha,15beta-triacetoxy-3alpha-benzoyloxy -4alpha-hydroxy -9,14-dioxo-13beta H-jatropha-6(17),11 E-diene ( 1) and 3beta,7beta,8beta,9alpha,14alpha,15beta-hexaacetoxy-2beta H-jatropha-5 E,11 E-diene ( 2) by 1D- and 2D-NMR (COSY, HMQC, HMBC and NOESY), IR, EI-MS and EI-FTICR-MS. Two known lathyrane derivatives, jolkinol A ( 3) and jolkinol A ( 4), whose (13)C-NMR spectra were assigned, were also isolated. Compounds 1 - 3 have been evaluated for their ability to inhibit the in vitro growth of three human tumour cell lines representing different tumour types, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and SF-268 (CNS cancer). They inhibited both MCF-7 and NCI-H460 cell lines, with GI50 values ranging between 40.9 microM and 95.3 microM, but were found to be ineffective as growth inhibitors of the SF-268 cell line.