Sesquiterpenes from the whole plants of Parasenecio roborowskii

Six eremophilane-type (parasenolide A–F) and an eudesmane-type (parasenin) sesquiterpenoids, along with eight known sesquiterpenes, were isolated from the whole plants of Parasenecio roborowskii. The structures and absolute configurations of new compounds were elucidated using extensive spectroscopic analysis, including HRESIMS, 1D and 2D NMR experiments, the CD exciton chirality methods, and single-crystal X-ray crystallography. All isolated compounds were evaluated for cytotoxicity against five human cancer (HeLa, HepG2, K562, MDA231, and NCI-H460) cell lines and a murine melanoma B16 F10 cell line by MTT assay. Compounds 1–15 showed cytotoxic activities, especially compounds 3, 4, 8, 10, and 12. These five compounds showed broad spectrum activities against all the tested cancer cell lines with IC50 ranging from 9.2 to 35.5 μM. The study supports that eremophilenolides and eudesmane-type sesquiterpenes occur mainly in the genus Parasenecio and can be used as a chemosystematic marker of the genus.

Graphical abstractSix new eremophilane-type and an eudesmane-type sesquiterpenoids were isolated from Parasenecio roborowskii. Structures were elucidated by spectroscopic data, X-ray crystallography and CD exciton chirality methods. The cytotoxicities of all isolated compounds against six selected cancer cell lines were evaluated.Figure optionsDownload full-size imageDownload high-quality image (77 K)Download as PowerPoint slide