Jatrophane diterpenoids with cytotoxic activity from the whole plant of Euphorbia heliosocpia L

Eight undescribed jatrophane diterpenoids, euphohelinoids A-H, along with 11 known analogues were isolated from the whole plant of Euphorbia heliosocpia L. Among them, euphohelinoids A and B contain a rare type of jatrophane diterpenoid skeleton with a 7,8-seco scaffold. To the best of our knowledge, only two such jatrophane diterpenoids have been reported. In addition, euphohelinoids G and H belong to a rare class of jatrophane diterpene possessing a beta-hydroxy group at C-11. Structure elucidation of these undescribed diterpenoids was performed by spectroscopic analysis, including NMR, HRESIMS, IR, electronic circular dichroism (ECD) and DP4+ analysis. The cytotoxicity of 17 abundant jatrophane diterpenes was evaluated against HepG2, HeLa, HL-60, and SMMC-7721 cell lines. Seven compounds presented potent cytotoxicity against the four tested cell lines with IC50 values from 8.1 to 29.7 mu M. Moreover, preliminary structure-activity relationships for these jatrophane diterpenoids were discussed.