Chemical composition and anti-inflammatory activities of essential oil from Trachydium roylei

Abstract

Chemical composition, anti-inflammatory activity, and cytotoxicity of essential oils obtained from the aerial parts of Trachydium roylei were investigated in this study. The chemical composition of T. roylei essential oil was analyzed using gas chromatography mass spectrometry. Fifty-nine components, representing 98.87% of the oils, were characterized. The oils were predominated by aromatic compounds and monoterpene hydrocarbons, and the main components were myristicin (25.35%), β-phellandrene (22.95%), elemicine (7.69%), isoelemicin (5.48%), and cedrol (5.26%). The anti-inflammatory activity of the oil in lipopolysaccharide-stimulated murine RAW 264.7 cells was evaluated. The oils downregulated the production of proinflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-1β, and IL-6, and significantly increased the anti-inflammatory cytokine IL-10 levels. Results indicated that the oils effectively inhibited the secretion of nitric oxide and prostaglandin E2 in lipopolysaccharide-stimulated macrophages. Western blot analyses were performed to determine whether the inhibitory effects of the oils on proinflammatory mediators (nitric oxide and prostaglandin E2) were related to the modulation of inducible nitric oxide synthase and cyclooxygenase-2 expression. These findings suggest that T. roylei essential oils exert an anti-inflammatory effect by regulating the expression of inflammatory cytokines.

Keywords: Trachydium roylei; anti-inflammatory activity; chemical composition; essential oil.

Figure 1

Growth inhibitory effect of Trachydium roylei essential oil in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Values are expressed as mean ± standard deviation (n = 3). * p < 0.001 compared with the LPS-only treatment group. Ctrl = control.

Figure 2

(A) Effects of Trachydium roylei essential oil on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α production of RAW 264.7 macrophages; (B) effects of T. roylei essential oil on LPS-induced interleukin (IL)-1β production of RAW 264.7 macrophages; (C) effects of T. roylei essential oil on LPS-induced IL-6 production of RAW 264.7 macrophages; and (D) effects of T. roylei essential oil on LPS-induced IL-10 production of RAW 264.7 macrophages. Values are expressed as mean ± standard deviation (n = 3). * Indicates p < 0.001 compared with the control group. ** p < 0.01 compared with the LPS-only treatment group. *** p < 0.001 compared with the LPS-only treatment group.

Figure 3

(A) Effects of Trachydium roylei essential oil on lipopolysaccharide (LPS)-induced nitric oxide production of RAW 264.7 macrophages; and (B) effects of T. roylei essential oil on LPS-induced prostaglandin E2 (PGE2) production of RAW 264.7 macrophages. Values are expressed as mean ± SD (n = 3). * Indicates p < 0.001 compared with the control group. ** Indicates p < 0.001 compared with the LPS-only treatment group. Ctrl = control.

Figure 4

Inhibitory effect of T. roylei essential oil on protein expression of iNOS and COX-2 in LPS-stimulated RAW 264.7 cells. The results presented are representative of three independent experiments. Values are expressed as mean ± SD (n = 3). ### indicates p < 0.001 compared with the control group. **, and *** indicate p < 0.01, and p < 0.001, respectively, compared with the LPS-only treatment group. TREO=essential oil from Trachydium roylei; Ctrl=control.