Helioscopianoids A–Q, bioactive jatrophane diterpenoid esters from Euphorbia helioscopia

The EtOH extracts of the whole plants of Euphorbia helioscopia afforded 17 new jatrophane diterpenoid esters, helioscopianoids A–Q (1—17), along with eight known compounds (18–25). Their structures were elucidated by extensive spectroscopic methods and Mo(2)(OAc)(4)-induced ECD analysis, and the structures of compounds 1, 2, and 7 were confirmed by X-ray crystallography. Compounds 1–17 were evaluated for inhibitory effects on P-glycoprotein (P-gp) in an adriamycin (ADM)-resistant human breast adenocarcinoma cell line (MCF-7/ADR) and neuroprotective effects against serum deprivation-induced and rotenone-induced PC12 cell damage. Compounds 8 and 16 increased the accumulation of ADM in MCF-7/ADR cells by approximately 3-fold at a concentration of 20 μmol/L. Compound 8 could attenuate rotenone-induced PC12 cell damage, and compounds 2, 8, and 12 showed neuroprotective activities against serum deprivation-induced PC12 cell damage.