Two new monoterpene lactones from Ligularia rumicifolia (J.R.Drumm.) S.W.Liu and their anti-proliferative activities

Abstract A phytochemical study of the EtOAc extract of Ligularia rumicifolia (J.R.Drumm.) S.W.Liu led to the isolation of two new monoterpene lactones ( 1 - 2 ) named (2 S ,3 S ,5 R )-5-ethyl-2,3-dimethyl-6-oxoterahydro-2 H -pyran-2-carboxylic acid and (2 S ,3 S ,5 R )-5-ethyl-2,3-dimethyl-6-oxoterahydro-2 H -pyran-2-carboxylic acid methyl ester, along with nine known compounds ( 3 - 11 ). All compounds were isolated from this species for the first time. Their structures were established on the basis of spectroscopic methods. The cytotoxic activity of Compound 2 was weak, with the lowest IC 50 value of 80.84 μM against MCF-7 cells. Compound 1 exhibited better anti-proliferative activities against MCF-7, T-24, HepG-2 and SKOV-3 cell lines than Compound 2 , with the lowest IC 50 value of 66.12 μM against MCF-7 cells.