Mamani-Matsuda and colleagues have worked with rat models of arthritis, which correlates well to what happens in humans in terms of macrophage markers, and demonstrated that quercetin reduced the production of nitric oxide (NO), tumor necrosis factor (TNF-α), monocyte chemoattractant protein 1 (MCP-1), and interleukin 1 beta (IL-1β), which are the primary inflammatory and pro-arthritic mediators of macrophages [61]. Here, IL1B is linked to arthritic joint disease.