In the current study, two new flavones, 4'-O-geranyltricin (1) and 3'-O-geranylpolloin (2), and a new 2-(2-phenylethyl)-4H-chromen-4-one derivative, 7-hydroxyl-6-methoxy-2-(2-phenylethyl)chromone (3), have been isolated from the stem barks of A. sinensis, together with 21 known compounds 4-24. The structures of new compounds 1-3 were determined through spectroscopic and MS analyses. Compounds 2, 3, 5, 6, and 8-10 exhibited inhibition (IC50≤12.51 μM) of superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). Compounds 3, 6, 8, 10, and 19 inhibited fMLP/CB-induced elastase release with IC50 values≤15.25 μM. This investigation reveals bioactive isolates (especially 2, 3, 5, 6, 8, 9, 10, and 19) could be further developed as potential candidates for the treatment or prevention of various inflammatory diseases.
Keywords: 2-(2-phenylethyl)-4H-chromen-4-one; Aquilaria sinensis; Thymelaeaceae; anti-inflammatory activity; flavone; structure elucidation.