Japonicones Q-T, four new dimeric sesquiterpene lactones from Inula japonica Thunb.

Abstract Four new dimeric sesquiterpene lactones (japonicones Q–T, 1 – 4 ) were isolated from the aerial part of Inula japonica Thunb., together with two known ones. Their structures were determined mainly by 1D and 2D NMR spectroscopic techniques including HSQC, 1 H–H COSY, HMBC, and NOESY. Herein, the inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages of 1 – 6 were evaluated; IC 50 values were tested as 8.5, 8.9, 4.3, 4.3, 4.2, and 9.2 μM, respectively.