Botanical Extracts from Rosehip (Rosa canina), Willow Bark (Salix alba), and Nettle Leaf (Urtica dioica) Suppress IL-1𝜷-Induced NF-κB Activation in Canine Articular Chondrocytes

Figure 11

Inhibitory effects of botanical extracts on IL-1β-induced NF-κB activation in chondrocytes in vitro. IL-1β stimulates the IL-1β receptor, initiating an intracellular signal transduction cascade, which activates the cytoplasmic IκBα kinases (Iκκ)-α, Iκκ-β, and Iκκ-γ. These kinases phosphorylate inactive IκBα. Phosphorylated IκBα is then ubiquitinated and degraded by the proteasome and active NF-κB is released. NF-κB translocates to the nucleus, where it activates proinflammatory and proapoptotic gene production. In chondrocytes, botanical extracts inhibit the NF-κB signal transduction pathway, ubiquitination of phosphorylated IκBα and block translocation of activated NF-κB to the nucleus.