Discovery of Highly Oxidized Abietane Diterpenoids from the Roots of Euphorbia fischeriana with Anti‐tumor Activities.

Main observation and conclusion: Four previously undescribed ent‐abietane diterpenoids (1—4), along with eleven known analogues (5—15), were isolated from the roots of wild Euphorbia fischeriana. Their gross structures were determined via extensive spectroscopic data, and the absolute configurations were elucidated by means of single‐crystal X‐ray diffraction analysis, Rh2(OCOCF3)4‐induced CD spectrum and ECD calculations. Their cervical carcinoma inhibition activities counteract HeLa cells were screened by MTT assay, and the structure‐activity relationships were further examined. The results demonstrated that 2 (IC50 value at 3.75 μmol/L) was more potent than cisplatin. The underlying mechanism study revealed that 2 could distinctly induce apoptosis accompanied by increasing reactive oxygen species (ROS) production, Ca2+ influx and decreasing mitochondrial membrane potential. Furthermore, signal pathways including MAPKs/AKT might play a significant role in 2‐induced cervical cancer cells death. [ABSTRACT FROM AUTHOR]