Anti-inflammatory Effects of Ethanol Extract of Korean Medicinal Plants at Hwaak Mountain in LPS-induced RAW 264.7 Macrophages

Objectives : This study was conducted to investigate candidate materials as anti-inflammatory agent from extracts of Korean medicinal plants in Hwaak mountain. Ligustrum obtusifolium (LO) is a Korea medicinal plants that commonly used for robustness and hemostasis. It has been reported that LO has exhibited anti-ischemic, anti-oxidative, anti-hypolipidemic, anti-tumor and hypoglycemic effects. However, LO has not been previously reported to have an anti-inflammatory effect. Therefore, we have evaluated the anti-inflammatory effects of LO and its underlying molecular mechanisms in LPS-induced RAW 264.7 macrophages. Methods : Cell viability was determined by MTT assay in RAW 264.7 macrophages. Nitric Oxide (NO) was measured with Griess reagent and pro-inflammatory cytokines were detected by ELISA in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Protein expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and p65 subunit of nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) were determined by Western blot analysis. Results : Among 15 extracts of Korean medicinal plants tested, Ligustrum obtusifolium (LO) showed the inhibition of NO production without cytotoxicity. LO reduced the expression levels of iNOS and COX-2 proteins in LPS-simulated RAW 264.7 macrophages in dose-dependent manner. Consistent with these data, LO inhibited the productions of $TNF-{\alpha}$, IL-6, and $IL-1{\beta}$ in LPS-simulated RAW 264.7 macrophages. Furthermore, LO attenuated the LPS-induced nuclear translocation of p65 $NF-{\kappa}B$ in RAW 264.7 macrophages involving suppression of $NF-{\kappa}B$ activation. Conclusions : Taken together, these results suggest that the anti-inflammatory effects of LO is associated with regulation of inflammatory mediators via inhibition of $NF-{\kappa}B$ activation in LPS-treated RAW 264.7 macrophages.