Unusual ingenoids from Euphorbia erythradenia Bioss. with pro-apoptotic effects.

Dichloromethane-acetone extract of Euphorbia erythradenia Bioss., a spurge endemic to the Iran, afforded four novel tetrahydroingenol diterpenes, one new myrsinane type diterpene, and two known triterpenes. Tetrahydroingenoids are novel compounds not only for the double bond reduction but also for their unique hydroxylation pattern at C-11 and C-13. The structures of these compounds were elucidated by spectroscopic methods, and especially 2D NMR measurements. The biological effects of the compounds were done by the MTT and Annexin V-FITC & PI staining assays on different cancer cell lines. The results obtained on EJ-138, CAOV-4, and OVCAR-3 cell lines suggested that tetrahydroingenanes inhibit cell proliferation through apoptosis in cancer cell lines. In conclusion, the new pattern of hydrogenation and hydroxylation of these compounds compared to other ingenoids, along with their apoptosis inducing properties on cancer cells, makes them of great interest for more investigation.