Cyanidin-3-glucoside inhibits inflammatory activities in human fibroblast-like synoviocytes and in mice with collagen-induced arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint tissue inflammation. Cyanidin-3-glucoside (C3G) is a major component in the flavonoid family and has shown anti-inflammatory, anti-oxidant and anti-tumour activity. In this study, we investigated the effects of C3G on lipopolysaccharides (LPS)-induced inflammation on human rheumatoid fibroblast-like synoviocytes (FLS) and on collagen-induced arthritis (CIA) mice model. We treated FLS with C3G followed by LPS induction, the expressions of tumour necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta) and IL-6 and the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B) and mitogen-activated protein kinase (MAPK) signalling pathway were analyzed. CIA was induced in mice and the arthritic mice were treated with C3G for 3 weeks. The disease severity was compared between control and C3G treated mice. The serum levels of TNF-alpha, IL-1 beta and IL-6 were analyzed by ELISA. C3G inhibited LPS-induced TNF-alpha, IL-1 beta and IL-6 expression in FLS. Moreover, C3G inhibited LPS-induced p65 production and I kappa Ba, p38, ERK and JNK phosphorylation. Administration of C3G significantly attenuated disease in mice with CIA and decreased the serum level of TNF-alpha, IL-1 beta and IL-6. C3G inhibited LPS-induced inflammation in human FLS by inhibiting activation of NF-kappa B and MAPK signalling pathway. C3G exhibited therapeutic effects in mice with CIA.