Cytotoxic diterpenoids from the roots of Euphorbia stracheyi

Three new diterpenoids, euphstrachenols A-C (1, 2, and 11), together with nineteen known analogues were isolated from the roots of Euphorbia stracheyi. Compounds 1 and 2 were lathyrane-type diterpenoids with a decadienoyl acidic moiety. Compound 11 was an ingenane-type diterpenoid with a deca-2 '' E,4 '' E,6 '' E-trien-1-one moiety. Their structures were elucidated by comprehensive spectroscopic analyses. All the isolated compounds were evaluated in vitro for their cytotoxic activity against four human cancer cell lines and a murine cell line, and compounds 1, 2, 4, 5, 7, 9, and 11-14 exhibited moderate cytotoxicity against MV4-11 cell line with IC50 values from 3.48 to 30.02 mu M.