UPLC-PDA determination of paeoniflorin in rat plasma following the oral administration of Radix Paeoniae Alba and its effects on rats with collagen-induced arthritis.

Rheumatoid arthritis (RA) is a chronic disabling autoimmune disease with characteristics of chronic, progressive inflammatory joint synovial damage, which mainly encroaches upon the synovium of the joint. The use of traditional medicine to treat RA slows the development of RA to a certain extent; however, it often has numerous side-effects. Therefore, the focus of RA research is the identification of a new, safe and effective medicine. The aim of the present study was to use an ultra performance liquid chromatography and photo diode array (UPLC-PDA) method to detect the paeoniflorin component in a Radix Paeoniae Alba decoction and in rat plasma following the oral administration of Radix Paeoniae Alba decoction. In addition, the effects of paeoniflorin on collagen-induced arthritis (CIA) in rats were investigated. The results indicate that a UPLC-PDA method for determining the presence of paeoniflorin in the Radix Paeoniae Alba decoction was successfully established. The method was fast, simple, sensitive, precise and valid. Paeoniflorin was shown to be a bioactive component of the Radix Paeoniae Alba decoction that was absorbed into rat plasma. Paeoniflorin significantly improved the disease resistant ability of RA rats and reduced the levels of the inflammatory cytokines, IL-1β and TNF-α, thereby inhibiting inflammation and bone erosion in the rats with CIA. The observations are likely to lay the foundation for further study of the mechanism of paeoniflorin in the treatment of RA.