Anti-inflammatory dimeric furanocoumarins from the roots of Angelica dahurica.

Seven new dimeric furanocoumarins, dahuribiethrins A-G (1-7), were isolated from the roots of Angelica dahurica. Their structures were determined by chemical derivatization and extensive spectroscopic techniques, including (1)H NMR, (13)C NMR, HSQC, (1)H-(1)H COSY, HMBC, and NOESY experiments. Compounds 2, 3, 4, and 5 exhibited significant inhibition of nitric oxide production in the lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with IC50 values in the range of 8.8-9.8 μM.