Research On The Anti-inflammatory Effect Of Burdock Fructo-oligsaccharide And The Underlying Mechanisms

Inflammation is the complex defense response of living organism with circulatory system to injury factors, but excessive inflammatory response can also damage the body. There are mainly two kinds of anti-inflammatory drugs used in clinical practice: non-steroidal anti-inflammatory drugs and steroidal anti-inflammatory drugs. Their clinical anti-inflammatory effect is significant, but large doses and long-time application of these drugs may bring series of side effects. The natural medicine is characterized by rich sources, low cost and less side effects. It has been reported that many kinds of natural medicines have anti-inflammatory effect. It is of great interest to find a novel natural anti-inflammatory medicine with high efficiency and low toxicity.Burdock, a biennial plant of the genus Arctium, is an excellent plant resource that has the concomitant function of both medicine and foodstuff. Burdock root has various biological activity and pharmacological effect. The burdock fructo-oligsaccharide (BFOS) is extracted and purified from Great Burdock root. It has been reported that BFOS has anti-fatigue and antitumor effects, and it can also improve immune function. But till now, there is no report related to the anti-inflammatory effect of BFOS.Our study focused on BFOS’s anti-inflammation effect. Inflammatory cell model was constructed on RAW264.7cell line stimulated by lipopolysaccharide (LPS). Our object is to investigate the anti-inflammatory effects of BFOS and to study the underlying mechanisms. [Background]Inflammation is defined as the defense reaction of organism to injury, which is a pathological process including damage and resistance to damage. Macrophage plays an important role in inflammation. LPS is an important inflammation-inducing factor, which can activate macrophages to release all kinds of cytokines leading to inflammation. LPS-treated macrophages are commonly used in the establishment of in vitro inflammation model. Nowadays more attention is paid on the anti-inflammatory effect of natural medicine because of its high efficiency, low toxicity and rich sources.Burdock is a typical kind of edible medical plants with wide pharmacological activity, while its side effects have not been reported. BFOS is the functional polysaccharides extracted from Burdock root. There has no report on its anti-inflammatory action till now. Our research is focused on the anti-inflammatory action of BFOS and the underlying mechanisms.[Objective]To investigate the anti-inflammatory effect and the possible mechanisms of burdock fructo-oligosaccharide, using the inflammatory model of RAW264.7cells.[Methods]Lipopolysaccharide was added to the medium of RAW264.7cell culture to establish the cell model of inflammation, and BFOS was used to observe its anti-inflammatory effect. The expression of Cyclooxygenase (COX-2), Nitric oxide synthases (iNOS), monocyte chemotactic protein-1(MCP-1) and Interleukin-6(IL-6) were detected by real-time PCR. The secretion of MCP-1and IL-6were determined by ELISA. The expression of COX-2, iNOS phosphorylated IκB, NF-κBp65, extracellular signal-regulated (Erk), P38and c-Jun N-terminal kinase (JNK) were detected by Western blot.[Results]1. Real-time PCR and ELISA results showed that the mRNA expression of IL-6, MCP-1and TNF-a and the secretion of MCP-1and IL-6were upregulated by LPS in RAW264.7cells; pretreatment with200、400、600μmol/L BFOS decreases the upregulation.2. Real-time PCR and Western blotting showed that the expression level of iNOS, COX-2were increased in RAW264.7stimulated by LPS, and the treatment of200、400、600μmol/L BFOS significantly decreased them.3. Western blotting showed that the phosphorylation expression level of NF-κBp65and IκB by LPS were increased in RAW264.7cells and this phosphorylation was inhibited by BFOS treatment.4. Western blot showed that LPS could up-regulate Erk, P38and JNK Phosphoryl-ation levels in RAW264.7cells and this phosphorylation was inhibited by BFOS treatment.[Conclusion]The expression level of iNOS, COX-2, MCP-1, IL-6and TNF-a were increased in RAW264.7stimulated by LPS, and the treatment of BFOS significantly decreased them. The results show that BFOS exerts anti-inflammatory effect on RAW264.7cells stimulated by LPS. In order to study the anti-inflammatory molecular mechanism of BFOS, we investigated the expressions of phosphorylated NF-κB p65, IκB, Erk, P38and JNK. Our results showed that the phosphorylation of these factors can be inhibited by BFOS treatment. These findings suggest that the anti-inflammatory effects of BFOS are mediated by suppression of NF-κB and MAPKs signal pathways.