The Anti-inflammatory Effects Of Alpinetin In Vitro And Vivo

Inflammation, characterized by redness, swelling, pain and asensation of heat, is one of the body’s self defence systems. This is aprotective mechanism of organisms to defense the injurious stimuli.While inflammation response has important role for host survival, it alsoleads to chronic inflammatory diseases. Chronic inflammation have beenreported to involved in the development of various diseases such asasthma, cancer, allergic rhinitis, rheumatoid arthritis and atopic dermatitis.Lipopolysaccharide (LPS), a main component of outer membrane ofGram-negative bacteria, has been referred as a key risk factor forGram-negative bacteria caused inflammation. It can lead to systemicinflammatory response ranging from shock, sepsis to multiple organ dysfunction, which cause great damage to the health of humans andanimals. Due to the increasing of antibiotic resistance in bacteria and theside effects of many chemical synthetic drugs, we are aiming at searchingdrugs with better curative effect and less side effects to treat inflammation.There are many advantages about traditional Chinese medicine such asless side effects and wider sphere of action. The effect of certaintraditional Chinese medicine on inflammation has been a topic of recentinterest. At present, a variety of traditional Chinese medicine has beenreported to have anti-inflammatory effects.Alpinetin, one of the main constituents of the seeds of Alpiniakatsumadai Hayata, belonging to flavonoids, has been known to exhibitantibacterial, anti-inflammatory and other important therapeutic activities.In the present research, the anti-infllammatory effects of alpinetin werestudied both in vitro and vivo. In Lipopolysaccharide (LPS) stimulated RAW264.7cells, the effects of alpinetin on pro-inflammatory cytokines(TNF-α, IL-6, and IL-1β) and signaling pathways (p65, p-p65, IκBα,p-IκBα, p38, p-p38, JNK, p-pJNK, ERK and p-ERK) were analyzed byenzyme-linked immunosorbent assay（ELISA）and Western blot. InLPS-induced vivo lung injury model, the concentrations of TNF-α, IL-6and IL-1β in the supernatants of the BALF were measured using ELISA.In addition, the number of inflammatory cells in BALF such asmacrophages and neutrophils, was analyzed by cell classificationnotation.The results showed that alpinetin markedly inhibited LPS-inducedTNF-α, IL-6and IL-1β production both in vitro and vivo. Furthermore,alpinetin blocked the phosphorylation of p65, IκBα protein, p38and ERKin LPS stimulated RAW264.7cells. In vivo study, pretreatment withalpinetin significantly decrease the number of total cells, neutrophils and macrophages. From in vivo study, it was also observed that alpinetinattenuated LPS-induced lung histopathologic changes in mouse models.These results suggest that alpinetin potentially decreases theinflammation in vitro and vivo, and might be a therapeutic agent againstinflammatory diseases.