Ligularia fischeri leaf extract suppresses proinflammatory mediators in SW982 human synovial cells.

Synovial hyperplasia is a hallmark of rheumatoid arthritis (RA) and is regarded as a major destructive element of articular bone and cartilage. This pathological process is accompanied by the production of proinflammatory cytokines and matrix metalloproteinases (MMPs) in synoviocytes. The present study was conducted to analyse the effects of Ligularia fischeri extract (LF) on inflammatory functions in the SW982 human synovial cell system. When cells were exposed to LF, LF had a significant inhibitory effect on the production of TNF-alpha, IL-6 and MMP-3 by SW982 cells (p < 0.05). The mitogen-activated protein kinases (MAPKs) represent an attractive target for RA because they can regulate MMP and cytokine expression. The effects of LF on the activation of MAPKs and transcription factors were also examined in SW982 cells by ELISA assay. IL-1beta-induced JNK and p38 activation was inhibited by LF, and LF significantly reduced the DNA-binding activity of transcription factors NF-kappaB and AP-1. Taken together, these results suggest that LF modulates the inflammatory process involved in arthritis by suppressing the expression of various genes by inhibiting NF-kappaB and/or AP-1 activities.