β-Patchoulene, isolated from patchouli oil, suppresses inflammatory mediators in LPS-stimulated RAW264.7 macrophages

beta-Patchoulene (beta-PAE) is a tricyclic sesquiterpene isolated from patchouli oil. According to our previous study, beta-PAE has anti-inflammatory activity in vivo; however, its anti-inflammatory response still remains unconfirmed in vitro. Therefore, this study is committed to demonstrate the anti-inflammatory effect of beta-PAE on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. According to our results, pre-treatment with beta-PAE significantly decreased the protein and messenger RNA (mRNA) levels of pro-inflammatory cytokines including tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, and IL-1 beta while increased the expressions of anti-inflammatory cytokines like IL-10 in a dose-dependent manner. In addition, real-time polymerase chain reaction (PCR) also revealed that beta-PAE could interrupt the mRNA expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and thus decreased the levels of nitric oxide (NO) and prostaglandin E-2 (PGE(2)) in LPS-stimulated RAW264.7 macrophages. In conclusion, these results indicated that beta-PAE exerted potent anti-inflammatory activity by maintaining the balance between pro- and anti-inflammatory cytokines as well as suppressing iNOS and COX-2 signaling pathways.