Polygoni Rhizoma Inhibits Inflammatory Response through Inactivation of Nuclear Factor‐kappaB and Mitogen Activated Protein Kinase Signaling Pathways in RAW264.7 Mouse Macrophage Cells

The objective of this study was to determine the antiinflammatory effects of Polygoni Rhizoma (PR), an Oriental medicinal herb, in interleukin 1 beta (IL‐1β) and lipopolysaccharide (LPS)‐stimulated RAW264.7 mouse macrophage cells. PR significantly reduced the production of pro‐inflammatory cytokines such as IL‐6, tumor necrosis factor alpha (TNF‐α) and pro‐inflammatory mediators such as inducible nitric oxide synthase (iNOS), nitric oxide (NO), cyclooxygenase 2 (COX‐2) and prostaglandin E2 (PGE2) even at a concentration of 1 µg/mL in the cells. In addition, PR inhibited the transcriptional activity of NF‐κB as well as the degradation and phosphorylation of inhibitory kappa B alpha (IκBα). Furthermore, PR suppressed the phosphorylation of extracellular signal regulated kinase 1/2 (ERK1/2), p38 and c‐Jun N‐terminal kinase 1/2 (JNK1/2) in IL‐1β and LPS‐treated RAW264.7. The results suggest that PR exerts an antiinflammatory property by inhibiting iNOS, COX‐2, TNF‐α and IL‐6 production in association with inactivation of the NF‐κB and MAPK signaling pathways in RAW 264.7 cells.