Study On The Molecular Mechanism Of Mogroside V Inhibiting Inflammation In RAW264.7 Cells

Momordica grosvenori is a valuable plant resource with edible and medicinal purposes,by exerting effects on treating sore throat and relieving constipation.Therefore,it is widely used with a long history in medicated diets and Traditional Chinese Medicine in Southeast Asia.Mogroside V（MV）,the main bioactive component from Momordica grosvenori,is a triterpene glycoside being commonly applied as a natural sweetener.Recent pharmacological studies had implied that crude mogroside had potent anti-inflammatory property;however,the underlying molecular mechanism remains unclear.In the inflammatory response,macrophages play a key role in initiating inflammation.Activated macrophages produce tumor necrosis factor（TNF-α）,interleukin（IL-1,IL6）,prostaglandin E2（PGE₂）and other cytokines,and recruit other immune cells involved in the inflammatory response.Lipopolysaccharide（LPS）,also known as lipopolysaccharide and endotoxin,is a common inflammatory factor triggered by inflammation.After acting on the surface of macrophages,LPS binds to lipopolysaccharide binding protein（LBP）and CD14 to form LPS-LBP-CD14 complex,and then binds to the surface of Toll-like receptors 4（TLR4）to induce a series of inflammatory signaling cascades to induce a large number of inflammatory proteins and inflammatory factors production,thereby enhancing and amplifying the inflammatory response..In this paper,MV with 98%purity was used to study the molecular mechanism of the anti-inflammatory effect of MV in the LPS-stimulated RAW264.7 cell inflammatory model.The main results were shown as follows:1.Cytotoxicity,Western blot and enzyme-linked immunosorbent assay indicated that（1）the concentration of MV between 0-640μM was not significantly toxic to cells.In LPS-induced RAW264.7 inflammatory cells,（2）MV significantly inhibited the generation of PGE₂and the expression of COX-2 in a dose-dependent manner.In addition,MV had no effect on the release of nitrite and the expression of iNOS protein.2.Molecular mechanism of MV inhibits the expression of COX-2.In the LPS-induced RAW264.7 inflammatory cells,（1）MV increased the stability of NF-κB in the cytoplasm and reduced the expressions of NF-κB and C/EBPδin the nucleus.（2）MV markedly increased the protein level of IκB-αand decreased the phosphorylation of IκB-α.（3）MV dose-dependently inhibited the phosphorylation of p-38,JNK,MEK and AKT1 induced by LPS.（4）Treated with MAPKs and AKT1 inhibitors significantly inhibited the expression of COX-2,and only the phosphorylation trend of AKT1 was consistent with the trend of COX-2 expression in all inhibitor groups.In conclusion,we can speculate that MV reduces the phosphorylation of AKT1,and reduces the phosphorylation of IκB-α,thereby blocking the nuclear of translocation NF-κB and the expression of C/EBPδin the nucleus.3.The potential mechanism of MV to prevent LPS-induced ROS production:（1）MV markedly reduces the generation of intracellular ROS in a dose-dependent manner.（2）AKT1specific inhibitor LY294002 completely reversed the increase of intracellular ROS caused by LPS.In conclusion,MV is most likely to prevent the increase of intracellular ROS caused by LPS by inhibiting the phosphorylation of AKT1.4.the potential molecular mechanism of Mogroside V inhibiting HO-1 overexpression:（1）AKT-1 specific inhibitor LY294002 completely inhibited the high expression of HO-1induced by LPS,and further date indicated that which be mediated by the key transcription factor ap-1（p-c-jun）rather than the transcription factor Nrf2.（2）MV dose-dependently inhibited the high expression of HO-1 and the phosphorylation of c-jun.In conclusion,MV may prevent high expression of HO-1 caused by LPS through the AKT1/AP-1 pathway.The above research results show that in addition to the function of functional sweeteners,MV also has a very significant anti-inflammatory effect,which can be used to develop a series of functional foods,special medical foods,and even natural anti-inflammatory new drug that can improve immunity and anti-inflammatory effects.The content and conclusions of research will increase the utilization of Momordica grosvenori in nutrition intervention,significantly improve the economic benefits and added value of Momordica grosvenori industry,and vigorously promote the development of Momordica grosvenori industry towards high-tech health.