This study was conducted to isolate the anti-neuroinflammatory component(s) in the 80% EtOH extract of P. tinctoria, and to investigate underlying molecular mechanism of the anti-neuroinflammatory component(s) in LPS-induced BV2 microglial cells. To isolate the active component(s) in the extract, various chromatographic methods were employed, and the structures of the isolated secondary metabolites were determined mainly by analysis of spectroscopic data such as NMR and MS data. Tryptanthrin (1), isolated from P. tinctoria extract, significantly inhibited the protein expression of iNOS and COX-2, and reduced the levels of their products (NO and PGE