When assessing rheumatoid arthritis progression with clinical scoring, as well as radiographic and histological examinations, collagen-induced arthritis rats administered with CA at a dose of 75 mg/kg BW daily by oral gavage for 21 days showed reduced swollen paw volume, joint swelling, bone erosion, destruction and arthritis severity, as well as reduced IL-6 levels in serum, compared to both control rats and collagen-induced arthritis rats administered orally with methotrexate (MTX), suggesting that CA could markedly ameliorate RA in rats to achieve enhanced joint protection. Here, IL6 is linked to rheumatoid arthritis.