Anti-inflammatory effect of essential oil and its constituents from 0 Cross Mark fingered citron (Citrus medica L. var. sarcodactylis) through blocking JNK, ERK and NF-κB signaling pathways in LPS-activated RAW 264.7 cells

We investigated the composition of essential oil from fingered citron (Citrus medica L. var. sarcodactylis) (FCEO) peels by GC-MS and its anti-inflammatory effects on lipopolysaccharide (LPS) - stimulated mouse macrophage (RAW 264.7) cells. Fifteen compounds, representing 98.97% of the essential oil, were tentatively identified; the main constituents were limonene (52.44%) and gamma-terpinene (28.41%). FCEO significantly inhibited nitric oxide (NO) and prostaglandin E2 (PGE2) by suppressing the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, respectively. Additionally, FCEO suppressed the production of tumor necrosis. factor-alpha (TNF-alpha), interleukin (IL)-1 beta, and IL-6. FCEO attenuated LPS-induced nuclear factor-kappa B (NF-kappa B) activation via inhibition of inhibitor KB-alpha phosphorylation. Furthermore, FCEO blocked activation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) but not that of p38 mitogen-activated protein kinase. These results indicate that FCEO inhibits LPS-stimulated inflammation by blocking the NF-KB, JNK, and ERIC pathways in macrophages, and demonstrate that FCEO possesses anti-inflammatory properties. (C) 2013 Elsevier Ltd. All rights reserved.