Mechanisms involved in the therapeutic effects of Paeonia lactiflora Pallas in rheumatoid arthritis.

Paeonia lactiflora Pallas, also named Chinese Paeony, is a Chinese herb. A decoction of its root has been used to treat painful or inflammatory disorders in traditional Chinese medicine. A water/ethanol extract of Radix Paeoniae is known as total glycosides of paeony (TGP), of which paeoniflorin is the major active component. Preclinical studies show that TGP/paeoniflorin is able to diminish pain, joint swelling, synovial hypertrophy, and the severity of bone erosion and cartilage degradation in experimental arthritis. TGP/paeoniflorin suppresses inflammatory process by reducing the production of prostaglandin E2, leukotriene B4, nitric oxide, reactive oxygen species, proinflammatory cytokines and chemokines. TGP/paeoniflorin also inhibits the proliferation of lymphocytes and fibroblast-like synoviocytes, the formation of new blood vessels, and the production of matrix metalloproteinases. Clinical data show that TGP is effective to relieve the symptoms and signs of rheumatoid arthritis without significant adverse effects. Recently, TGP is widely used to treat rheumatoid arthritis in China.