Abstract:Two new sesquiterpenoid lactones, namely eupalinilides K and L, were isolated from Eupatorium lindleyanum DC. Their structures were determined by spectral methods, including 1D- and 2D-NMR spectra. Cytotoxic evaluation showed that eupalinilide L exhibited potent cytotoxicity against P-388 and A-549 tumor cell lines with IC50 values of 0.17 and 2.60 μmol/L, respectively.(Author for correspondence.E-mail: jmyue@mail.shcnc.ac.cn)