Anti-inflammatory effects of essential oils extracted from Chamaecyparis obtusa on murine models of inflammation and RAW 264.7 cells

Antimicrobial, antifungal and anti-inflammatory effects of essential oils extracted from Chamaecyparis obtusa (EOCO) have previously been reported. In the present study, the anti-inflammatory effects of EOCO were investigated in two murine models of inflammation: Carrageenan-induced paw edema and thioglycollate-induced peritonitis, and in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. The expression levels of proinflammatory cytokines were analyzed by ELISA, the expression of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were determined by western blotting, and nitrite concentration was measured using Griess reagent. In mice with carrageenan-induced edema, paw thickness and the expression levels of interleukin (IL)-1 beta and IL-6 in paw homogenates were significantly decreased in the EOCO (5 and 10 mg/kg) group, as compared with the control group. In mice with thioglycollate-induced peritonitis, treatment with EOCO (5 and 10 mg/kg) reduced the number of total cells and suppressed tumor necrosis factor-alpha (TNF-alpha), IL-1 beta and IL-6 levels in peritoneal fluid. In addition, EOCO reduced nitric oxide, TNF-alpha and IL-6 production, and suppressed iNOS and COX-2 expression in LPS-stimulated RAW 264.7 cells. These results suggest that EOCO may exert anti-inflammatory effects in vivo and in vitro, and that these effects may be associated with the inhibition of inflammatory mediators. Therefore, EOCO may be considered an effective therapeutic agent for the treatment of inflammatory diseases.