Chemical constituents from the aerial parts of Euphorbia sikkimensisand their bioactivities

Phytochemical investigation of the aerial parts of Euphorbia sikkimensisled to the isolation of one new diterpenoids, named sikkimenoid E (1), together with thirteen other known compounds (2–14). Their structures were established by means of spectroscopic methods. Compound 2was identified to be a trinortriterpenoid, and derived for the first time from a natural source. In this paper we reveal for the first time its comprehensive spectral data and NMR spectral assignment. Compound 4showed antiangiogenic activity with an IC50value of 5.66 µM in a zebrafish model, and compounds 5and 6exhibited cytotoxicity toward A549 cell line with IC50values of 12.12 and 6.45 µM, respectively.