Antiarthritic effects of Ethyl acetate fraction from Brassica rapa (EABR) through suppression of NF-κB

In an attempt to identify bioactive natural products with anti-inflammatory activity, we evaluated the anti-inflammatory and antiarthritic potential of Brassica rapa (Brassicaceae) in activated macrophages and an experimental arthritis rats model. Ethyl acetate fraction from B. rapa (EABR) was found to reduce the productions of PGE₂, NO, TNF-α, and IL-6, and expressions of COX-2, iNOS, TNF-α, and IL-6 in LPS-induced macrophages. EABR attenuated LPS-induced DNA-binding, transcriptional activities, nuclear translocation, and phosphorylation of NF-κB. These effects are paralleled with reduction in the degradation and phosphorylation of IκBα and IKK activation. In rats with acute inflammation, oral administration of EABR reduced paw swelling and release of PGE₂ and MPO in carrageenan-injected tissue. In rat with adjuvant-induced arthritis, ERBR significantly reduced the paw swelling and arthritic index compared with the vehicle group. Moreover, anti-arthritic effects of EABR correlated with significant decrease of inflammatory mediators and inhibition of NF-κB activation in paw homogenates. Hence, these results clearly indicate that EABR is a potential therapeutic agent for arthritis and inflammatory-associated disorders.