Quercetin and Its Role in Reducing the Expression of Pro-inflammatory Cytokines in Osteoarthritis

Osteoarthritis is the most common human joint disease in the world. It is also one of the most common skeletal muscle defects, destructive joint changes, and the leading cause of disability and reduced quality of life. Destructive changes in inflammatory joints are associated with a range of biochemical events, including the overproduction of inflammatory cytokines. Cytokines are protein compounds that play an essential role in causing and regulating inflammation. A balance between pro-inflammatory and anti-inflammatory cytokines is crucial in maintaining a stable body. In some inflammatory diseases, including osteoarthritis, the balance between these compounds is disturbed, and the balance shifts to pre-inflammatory cytokines. For this reason, researchers today are trying to find an effective way to reduce inflammation and treat osteoarthritis by using certain compounds. Current treatments for osteoarthritis, including nonsteroidal antiinflammatory drugs, glucocorticoids, and hyaluronic acid, are mainly based on reducing pain and inflammation. However, they have limited effects in controlling symptoms and improving the patient's quality of life. Also, due to the high level of side effects, synthetic drugs have led to the identification of compounds of natural origin to give patients a chance to use painkillers and antiinflammatory drugs with fewer side effects. This review study aimed to present the role of quercetin as a natural compound in reducing the expression of pro-inflammatory cytokines in osteoarthritis. This study also discusses the relationship between inflammation and cartilage destruction and other inflammation-related factors caused by cytokines.