The CHCl3 soluble fraction of the 80% MeOH extract of the stems of Firmiana simplex strongly inhibited
nitric oxide production in lipopolysaccharide-activated BV-2 cells. A bioactivity-guided column chromatographic
separation yielded two new lignans, firmianols A and B (1–2) together with seventeen
known lignans (3–19). The structural elucidation of the new compounds was determined by spectroscopic
methods, including 1D, 2D NMR and HR-FAB-MS. All isolated lignans were evaluated for their
antineuroinflammatory effects on nitric oxide (NO) production in lipopolysaccharides (LPS)-activated
murine microglia BV2 cells. Among the isolated, compounds 14 and 15 showed potent inhibitory activity
against NO production (IC50 1.05 and 0.929 lM, respectively) without cell toxicity in murine microglia
BV-2 cells. Compounds 11–13 and 17 also exhibited strong inhibitory effects on NO production, with
IC50 values ranging from 7.07 to 15.28 lM.