Chemical constituents of Euphorbia tangutica.

Sixteen known compounds isolated from the whole plants of Euphorbia tangutica, including phorbol-13-actate (1) previously synthesised and obtained from a natural source for the first time, were evaluated in vitro against a panel of human cancer cell lines using the MTT method. Among them, ergosterol (6) exhibited significant cytotoxic activity against HL-60 cell line with an IC50 value of 3.3 mu M, and 3 beta,5 alpha-dihydroxy-15 beta-cinnamoyloxy-14-oxolathyra-6Z,12 E-diene (7) also displayed moderate activity.