Kaempferol-3-O-β-rutinoside suppresses the inflammatory responses in lipopolysaccharide-stimulated RAW264.7 cells via the NF-κB and MAPK pathways

Kaempferol-3-O-β-rutinoside is one of the compounds isolated from tartary buckwheat (Fagopyrum tatricum), and its biological effects have not been studied yet. The present study examined the anti.inflammatory effects of Kaempferol-3-O-β-rutinoside and explore its regulatory mechanisms in lipopolysaccharide (LPS)-induced macrophage RAW264.7 cells. Kaempferol-3-O-β-rutinoside exhibited no cytotoxic effect in RAW 264.7 macrophage and 293 cell lines up to 300 μM. As the concentration of Kaempferol-3-O-β-rutinoside was increased, the activity of nitric oxide was inhibited in LPS-stimulated RAW264.7 cells. In addition, Kaempferol-3-O-β-rutinoside treatment downregulated the expression of inflammation-related cytokines tumor necrosis factor-α and interleukin-6 in LPS-stimulated RAW264.7 cells. Furthermore, Kaempferol-3-O-β-rutinoside treatment suppressed inflammatory-mediated factors, such as inducible nitric oxide synthase and cyclooxyganse-2. These inflammation-related proteins are known to be regulated by NF-κB and mitogen-activated protein kinase (MAPK) signaling, therefore the effect of Kaempferol-3-O-β-rutinoside on these pathways was investigated. The results demonstrated that Kaempferol-3-O-β-rutinoside decreased the expression of inhibitor of βB (IβB) protein and IβB kinases; as a result, the nuclear translocation and expression of NF-βB was inhibited in LPS-stimulated RAW264.7 cells. Furthermore, Kaempferol-3-O-β-rutinoside inhibited the phosphorylation of p38, extracellular signal-regulated kinase and stress-activated protein kinase in LPS-stimulated RAW264.7 cells. Thus, the present data demonstrated that Kaempferol-3-O-β-rutinoside suppressed inflammation-related gene expression through the NF-κB and MAPK pathways, and suggested that it may be a useful reagent in pharmacological research.