Three new sesquiterpene lactones from Inula britannica.

One new 1,10-secoeudesmanolide (1), two eudesmanolides (2 and 3), together with nine known compounds (4-12) were isolated from the aerial parts of Inula britannica. The structures of the new compounds were elucidated by detailed spectroscopic analysis, including HRESIMS and 2D-NMR spectroscopic method. In addition, compounds 1-4 were tested for their inhibitory effects against LPS-induced NO production in RAW264.7 macrophages.