Biochanin-A, a phytoestrogen derived from herbal plants, protected from the IL-1 beta-induced loss of proteoglycans through the suppression of matrix degrading enzymes such as matrix metalloproteinase (MMP)-13, MMP-3, MMP-1, and ADAMTS-5 in primary rat chondrocytes and the knee articular cartilage. It also suppressed the expression of IL-1 beta-induced catabolic factors such as nitric oxide synthase 2, cyclooxygenase-2, prostaglandin E-2, and inflammatory cytokines. Furthermore, biochanin-A suppressed the IL-1 beta-induced phosphorylation of NF kappa B, and inhibited its nuclear translocation in primary rat chondrocytes. These results indicate that biochanin-A antagonizes the IL-1 beta-induced catabolic effects through its anti-inflammatory activity that involves the modulation of NF kappa B signaling. (C) 2016 Elsevier Inc. All rights reserved.