The chemical investigation of whole plants Euphorbia stracheyi Boiss from China led to the isolation of one new ent-kaurane diterpene, ent-Kaurane-16β,17,19-triol-3-one (1), along with three known ent-kaurane diterpenoids (2-4) as ent-Kaurane-3α,16β,17-triol (2)，ent-16S,17-dihydroxy-kaurane-3-one (3) and ent-3S,16S,17-trihydroxy-kaurane-2-one (4). Their structures were elucidated by extensive spectroscopic analyses including 1D, 2D NMR, HR-ESI-MS, and by comparison with the literature. Compound 2 was a new natural product and firstly isolated from nature, while compounds (3-4) were isolated from E. stracheyi for the first time. All isolated compounds (1-4) were evaluated for their cytotoxic activities against five human cancer cell lines (including A-549, SMMC-7721, HL-60, MCF-7 and SW-480).
Keywords: Euphorbia stracheyi; diterpenoid; ent-kaurane.