Anti-inflammatory Effect Of P-cyneme

Sepsis is an important contributor to human and animal diseases, which causes huge financiallosses every year. There are various factors which give rise to sepsis, besides bacterial infection(which is the main reason). Many of the pathological consequences of sepsis are attributable toLipopolysaccharide (LPS), a conserved component of the Gram-negative bacterium’s outermembrane. It has been indicated that it stimulates macrophages releasing pro-inflammation, suchas tumor necrosis factor α (TNF-α), interleukin1β (IL-1β), IL-6, and anti-inflammatory factors,such as interleukin10(IL-10). These cytokines amplify the response of inflammation by mutualeffect, and disrupt it. Recently, the signaling pathways participating in LPS-induced macrophageactivation have been extensively characterized. NF-κB and MAPKs are the most classicalpathways. NF-κB is one of the most ubiquitous transcription factors and regulates the genesinvolved in cellular proliferation, inflammatory responses, and cell adhesion. NF-κB is regulatedby activation of IκB kinase (IKK) complex, which phosphorylates cytosolic IκB proteins.MAPKsare a family that includes ERK, p38and JNK.The mortality of sepsis is high, but there are few effective drugs to reduce the mortality.Someantibodies and other agents which were designed to target inflammatory mediators didn’t showmuch benefit for controlling sepsis and improving the survival of patients and animals rate.Inrecent years, research has focused on inflammation signaling pathways as targets to control sepsis,and some progress has been made.Antibiotics perform outstanding contributions to prevention andtreatment of sepsis and other infectious diseases, but their numerous applications increase bacterialresistance.That forces people to shift their focus towards resource-rich herbs instead of antibiotics.In our study, we found p-cymene and magnolol have anti-inflammatory potential. There have beensome reports about the anti-inflammatory activities of magnolia. In addition, magnolol showedcytotoxicity in doses of50μg/mL. Thus, we chose p-cymene, the main active ingredient ofmagnolia, as the subject of further study.The anti-microbial activity of p-cymene in vitro has beenconfirmed, but its anti-inflammatory activity was rarely reported.The purpose of this study was to investigate the anti-inflammatory effects and mechanism of p-cymene in vitro and in vivo, and to evaluate the protection of p-cymene on LPS-induced murinesepsis models. In preliminary experiments, we evaluated p-cymene cytotoxicity towardsRAW264.7cells by MTT assay. P-Cymene didn’t show visible cytotoxicity at doses0to428.64μg/mL. To investigate the effect of p-cymene on the secretion of cytokines involved in theinflammatory process, such as TNF-α, IL-1β, IL-6, and IL-10, we designed pathological model invitro and in vivo. Meanwhile, the mRNA levels of cytokine genes were analyzed throughsemi-quantitative RT-PCR analysis in vitro. p-Cymene showed significant inhibition on release ofTNF-α, IL-1β and IL-6in vitro and in vivo, and reduced the levels of the relative mRNAs in vitro.In addition, it increased the production of IL-10in vivo. In further studies, we detected p-cymeneinactivated IκB and MAPKs (ERK, JNK, P38) by Western blot. It also significantly suppressedERK, JNK, P38and IκB pathway activation. Based on above studies, murine sepsis models wereestablished to evaluate the protection of p-cymene on sepsis mice. p-Cymene improved thesurvival rate of mice challenged by LPS. These results suggest that p-cymene may haveanti-inflammatory effects by blocking MAPKs and NF-κB pathways.