Flavones with anti-inflammatory activity isolated from the branches and leaves of Daphne retusa.

Daphne retusa belongs to the Daphne genus of Thymelaeaceae, which is widespread in northwest China, and its roots and stem bark are commonly used in Chinese folk medicine to treat rheumatism and congestion. In this study, four new (1-4) and eleven known (5-15) flavones were isolated from the branches and leaves of Daphne retusa, including six monomeric flavones (2-7) and nine dimeric flavones (1, 8-15). On the basis of chemical evidence and spectral data analysis (UV, ECD, NMR, and HR-ESI-MS), the structures of compounds 1-4 was elucidated. Furthermore, all compounds have been tested for their inhibitory effects on NO production in LPS-induced RAW 264.7 cells, and compounds 2 and 8 showed obvious inhibitory effect.