Scopoletin: an inducible nitric oxide synthesis inhibitory active constituent from Artemisia feddei.

Bioassay-guided fractionation of an H 2 O extract of Artemisia feddei has furnished an inducible nitric oxide synthase (iNOS) inhibitory coumarin, scopoletin (1) and one of the inactive sesquiterpenes, achillin (2). Compound 1 showed inhibition of nitric oxide (NO) synthesis in a dose-dependent manner in murine macrophage-like RAW 264.7 cells stimulated with interferon-y (IFN-γ) plus lipopolysaccharide (LPS). The inhibition of NO synthesis of was due to suppression of iNOS mRNA and iNOS protein, as determined by Northern and Western blotting, respectively.