Standardized ethyl acetate fraction from the roots of Brassica rapa attenuates the experimental arthritis by down regulating inflammatory responses and inhibiting NF-κB activation

•EABB is a standardized ethyl acetate fraction from the roots of Brassica rapa.•EABR reduced paw swelling, an arthritic index, serum RF, and RANKL/OPG ratio in AIA-induced arthritic rats.•EABR suppressed the productions of inflammatory mediators in arthritic rats and macrophages.•EABR attenuated the IKK- mediated IκBα degradation and subsequent NF-κB activation.•EABR exerts its anti-arthritic and anti-inflammatory properties via NF-κB inactivation.

This study was undertaken to investigate the anti-arthritic potential of a standardized ethyl acetate fraction from the roots of Brassica rapa (EABR) and to explore the molecular mechanisms in adjuvant-induced arthritic rats and macrophages. In AIA-induced arthritic rats, EABR significantly reduced paw swelling, an arthritic index, serum rheumatoid factor, and tissue expression ratio of RANKL/OPG versus vehicle-administered group. This was found to be well correlated with significant suppressions in productions of PGE2, NO, and pro-inflammatory cytokines and in activations of NF-κB in AIA-induced paw tissues and LPS-induced macrophages. EABR attenuated NF-κB activation by reducing the nuclear translocation and phosphorylation of the p65 NF-κB, which were accompanied by parallel reductions in the degradation and phosphorylation of IκBα after blocking the phosphorylation mediated IKK activation. The findings suggest EABR exerts its anti-arthritic and anti-inflammatory properties via NF-κB inactivation in vitro and in vivo, and that EABR is a potential therapeutic for the treatment of arthritis and inflammation-associated disorders.

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