Cytotoxic germacranolides and acyclic diterpenoides from the seeds of Carpesium triste

Four new highly oxygenated germacranolides (1, 4, 6, and 7) and four new acyclic diterpenes (8-11), along with three known germacranolides (2, 3, and 5), were isolated from the seeds of Carpesium triste. The structures of the new compounds were elucidated by spectroscopic methods including IR, HRESIMS, and 1D and 2D NMR experiments, and the absolute configurations of compounds 1 and 8-10 were established by CD and Mosher's methods, respectively. Compounds 1, 2, and 4-10 were evaluated for their in vitro cytotoxic activity against cultured SMMC-7721 (human hepatoma), HL-60 (human promyelocytic leukemia), and L02 (human hepatocyte) cell lines. Compounds 1, 2, and 4-7 exhibited significant cytotoxicity against HL-60 cells, and compound 10 exhibited cytotoxicity against SMMC-7721 cells.