Cumulative therapeutic effects of phytochemicals in Arnica montana flower extract alleviated collagen-induced arthritis: inhibition of both pro-inflammatory mediators and oxidative stress

BACKGROUND: The plant Arnica montana is used in folk medicine to alleviate pain, inflammation and swelling of muscles and joints associated with rheumatoid arthritis and other inflammatory conditions. The present study aimed to investigate the therapeutic effects and mechanism of action of A. montana flower methanol extract (AMME) against both inflammation and oxidative stress in a collagen-induced arthritis (CIA) rat model. RESULTS: Oral administration of AMME was found to reduce clinical signs and improve the histological and radiological status of the hind limb joints. AMME-treated rats had lower expression levels of nitric oxide, tumor necrosis factor-beta, interleukins (IL-1 beta, IL-6 and IL-12) and titer of anti-type II collagen antibody compared with untreated CIA rats. Furthermore, by inhibiting these mediators, AMME also contributed towards the reversal of disturbed antioxidant levels and peroxidative damage. CONCLUSION: The alleviation of arthritis in rats was very likely due to the combined action of phenolic and flavonoid compounds, the major constituents identified by gas chromatography/mass spectrometry (GC/MS) analysis. The study also shed some light on mechanisms involved in diminution of inflammatory mediators and free radical-generating toxicants and enhancement of the antioxidant armory, thereby preventing further tissue damage, injury and synovial hyperproliferation in arthritis. (C) 2015 Society of Chemical Industry