Stelleraguaianone B and C, two new sesquiterpenoids from Stellera chamaejasme L

Two new sesquiterpenoids were isolated from Stellera chamaejasme L., known as the traditional Chinese herb 'Rui Xiang Lang Du'. The compounds were elucidated as stelleraguaianone B (1) and C (2) by comprehensive spectroscopic analysis, including 1D and 2D NMR as well as HRESIMS, and by comparing their NMR data with known compounds. In addition, the structure of 1 was further confirmed by single-crystal X-ray diffraction analysis. Both the compounds were evaluated for their cytotoxicity on common tumour cell lines in vitro, which revealed that compound 1 exhibits cytotoxic activity on A549 cells, while 2 has no activity.