Comparison of anti-inflammatory effect between β-patchoulene epoxide and β-patchoulene in LPS-stimulated RAW264.7 macrophages

β-patchoulene (β-PAE) is one of the essential tricyclic sesquiterpenes of patchouli oil while β-patchoulene epoxide (β-PAO) is the oxidative product of β-PAE which can only be found in the oil with long storage period. Our previous researches demonstrated that both β-PAE and β-PAO exert potent anti-inflammatory activity in vivo, but which one is more valuable still remains uncertain. Therefore, this study adopts the model of LPS-stimulated RAW264.7 macrophages to compare β-PAO with β-PAE on the anti-inflammatory activity. According to our results, β-PAO was superior to β-PAE on anti-inflammation as evidence by lowering the protein and mRNA expressions of several pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-12 (IL-12), interleukin-1β (IL-1β), and monocyte chemotactic protein-1 (MCP-1). β-PAO was also better than β-PAE in reducing the productions of nitric oxide (NO) and prostaglandin E 2 (PGE 2 ) through inhibiting inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 signaling pathway. The results above provided experimental basis for the conclusion that β-PAO was more potent than β-PAE in anti-inflammatory activity in vitro.