Antioxidative and anti-inflammatory effects of Saururus chinensis methanol extract in RAW 264.7 macrophages

Natural products are known to be sources of bioactive components exerting antioxidative and anti-inflammatory activities. We evaluated the suppressive effects of the methanol extract (0-45 microg/mL) of the aerial parts of Saururus chinensis (Lour.) Baill (Saururaceae) on lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production and oxidative stress buildup in the RAW 264.7 murine macrophages. Treatment of RAW 264.7 cells with S. chinensis methanol extract (SME) significantly reduced LPS-stimulated NO production in a concentration-dependent manner. Treatment with SME reduced thiobarbituric acid-reactive substances accumulation and enhanced glutathione levels and activities of antioxidative enzymes, including superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase, in LPS-stimulated macrophages compared with LPS-only treated cells. Expression of inducible NO synthase (iNOS) mRNA was also suppressed in SMEtreated cells. The specific DNA binding activities of nuclear factor kappaB (NFkappaB) on nuclear extracts from SME-treated cells were significantly suppressed. These results suggest that SME has antioxidative and anti-inflammatory activities by enhancing antioxidative defense systems and suppressing NO production via the down-regulation of iNOS expression and NFkappaB activity.