Three new sesquiterpenes with cytotoxic activity from Dobinea delavayi

Three new sesquiterpenes dobinins A-C (1-3), together with five known compounds, were isolated from the root of Dobinea delavayi. The structures of the three new compounds were determined on the basis of spectroscopic analysis including 1D-, 2D-NMR and MS techniques as well as by comparison of the spectral data with those of analogous compounds reported in the literatures. Compounds 1-3 were screened for antitumor activity in vitro and exhibited definite cytotoxic activity against the human tumor cell line HL-60 with IC50 levels of 8.0 × 10-5, 4.7 × 10-5, and 5.1 × 10-5 M, respectively.