Chemical constituents from Euphorbia stracheyi and their biological activities.

Three new diterpenoids, stracheyioids A-C (1-3), as well as 36 known compounds (4-39) were isolated from the whole plants of Euphorbia stracheyi. Compound 1 was a rare 13-deoxy tigliane diterpenoid and compound 2 was an ingenol diterpenoid characterized by an unique 2Z,4Z-decadienoyl acidic moieties. All the known compounds were isolated from E. stracheyi for the first time. Their structures were elucidated on the basis of extensive spectroscopic interpretation. Compounds 1-39 were tested for their cytotoxicity against five cancer cell lines (A-549, MCF-7, Hep G2, Hela and P388) and showed IC50 values in the range 6.64-42.86 μM. The antiangiogenic activities of the isolated compounds were also evaluated using a zebrafish model.