Background Maillard reaction products (MRPs) are known to have antioxidant, antimutagenic and anticardiogenic activities. The antioxidant capacity of MRPs is comparable to those of commonly used food antioxidants; butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and a-tocopherol. Maillard reaction (MR) could produce non-enzymatically colored or colorless products such as glucose-tyrosine, glucose-lysine, fructose-lysine, ribose-lysine, xylose-arginine, xylose-glycine and xylose-tryptophanRecently, we synthesized (E)-2,4-bis(p-hydroxyphenyl)-2-butenal using tyrosine and fructose under a typical MR condition of high temperature and pressure.
Objectives Objective of this study was to assess anti-arthritis effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal and its action mechanisms.In the present study, we investigated whether (E)-2,4-bis(p-hydroxyphenyl)-2-butenal can have anti-inflammatory activity and anti-arthritic activities through inhibition of NF-kB/IKK and STAT3 pathways in cultured macrophage and synoviocytes, and collagen-induced arthritis (CIA) animal model.
Methods Nitric oxide (NO) and prostaglandin E2 assay, electrophoretic mobility shift assay, luciferase assay, Western blot, real-time PCR and pull-down assay were used for mechanism studies. Anti-inflammatory effect was done in cultured RAW 264.7 cells and synoviocytes, and collagen-induced arthritis model was used for evaluation of anti-inflammation and anti-arthritis effects in vivo. Binding target of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal was identified using pull-down assay and sol-gel biochip assay, and its binding site was proposed through a docking experiment.
Results (E)-2,4-bis(p-hydroxyphenyl)-2-butenal (2.5-10 mg/ml) inhibited lipopolysaccharides (1 mg/ml)-induced pro-inflammatory responses through downregulating IkB kinase b (IKKb)/nuclear factor-kapaB (NF-kB) and signal transducer and activator of transcription 3 (STAT3) pathways in RAW 264.7 cells and synoviocytes. (E)-2,4-bis(p-hydroxyphenyl)-2-butenal not only suppressed the collagen (100 mg/0.1ml)-induced arthritic responses through inhibition of IKKb/NF-kB and STAT3 activities but also reduced the extent of bone destruction and fibrosis in joint tissue. The population of white blood cells in blood and NO generation in murine splenic T cells of collagen-induced arthritic mice were significantly reduced by (E)-2,4-bis(p-hydroxyphenyl)-2-butenal. Sol-gel biochip analysis proved that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal directly binds to IKKb, and thus inhibit its activity. A docking experiment and pull-down assay indicate that IKKb might be a potential target of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal.
Conclusions These findings indicated that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal exerted its anti-inflammatory and anti-arthritic effects through inhibition of IKKb/NF-kB activity via direct binding to IKKb, and that it could be a useful agent for the treatment of arthritic diseases.
Hwang IG, Kim HY, Woo KS, Hong JT, Hwang BY, Jung JK, et al. Isolation and characterisation of an a-glucosidase inhibitory substance from fructose–tyrosine Maillard reaction products. Food Chemistry 2011;127:122–6.
Disclosure of Interest None Declared