Investigation of the ethanol extract of the whole plant of Ainsliaea yunnanensis led to the isolation of four new dimeric sesquiterpene lactones, ainsliadimer F-I (1-4), together with seven known dimeric sesquiterpene lactones (5-11) and ten sesquiterpenes (12-21). Their structures were elucidated by spectroscopic methods. The relative stereochemistry of ainsliadimer F was further confirmed by single crystal X-ray diffraction analysis. Compounds 1-21 were tested for the inhibition of nuclear factor kappa B (NF-κB) in the 293-NF-κB-luciferase reporter cell line induced by lipopolysaccharide (LPS), and Compounds 5, 18, 20 and 21 were further tested for the production of TNF-α, IL-1β, IL-6 and IL-10 in RAW 264.7 macrophages induced by LPS. Compounds 5, 18, 20 and 21 exhibited significant activity in anti-inflammatory activity assays.
Keywords: Ainsliaea; Ainsliaea yunnanensis; anti-inflammatory activity; sesquiterpenoid.