Study on the compatibility effect and active constituents of Atractylodis Rhizoma in Ermiao Wan against Acute Gouty Arthritis

Ermiao Wan (EMW), composed of Atractylodis Rhizoma (AR) and Phellodendri Chinensis Cortex (PC), is a classical traditional Chinese medicine prescription having been used to treat the disease named “Tong Feng”, which is described as “ache in bones and joints” with the same symptom of modern disease named acute gouty arthritis for many years in TCM clinical practice. Besides, both PC and AR were considered to be effective in anti-inflammatory according to modern pharmacological research. Present study was undertaken to probe the compatibility rationality between the two herbs PC and AR in EMW and the active constituents of AR against acute gouty arthritis (AGA). Rat model of AGA was induced by intra-articular injection of monosodium urate (MSU) crystal suspension, and PC combined with or without different AR extracts were used for AGA treatment. Ankle joint swelling, proinflammatory cytokines in serum and pathological changes of synovium were investigated. Using the developed UHPLC-QQQ-MS method, the plasma concentrations of the primary alkaloids in PC, such as berberine, phellodendrine, magnoflorine, jatrorrhizine, berberrubine, palmatine, and tetrahydropalmatine, in AGA rat were determined, and pharmacokinetics properties were compared following oral administration of PC, PC combined with or without different AR extracts. PC, PC combined with AR volatile oil (VO) extract or PC combined with whole AR extract significantly attenuated the ankle joint swelling of AGA rats. Besides, the combination of PC and VO extract of AR showed superior efficacy than other groups in ameliorating ankle joint swelling, reducing the IL-6 expression in serum and improving tissue lesions of ankle joints. Furthermore, it turned out that the VO extract of AR increased the blood exposure level of PC related alkaloids than non-volatile oil (NVO) extract of AR, by comparing the pharmacokinetic results of each group. The VO components of AR were the key compatible materials to combine with PC in EMW for AGA treatment. Moreover, the enhanced anti-AGA activity of PC after combining with VO extract of AR may attribute to the influence of VO on the pharmacokinetics of PC. This study may provide useful information for elucidating the compatibility effects of AR in EMW against AGA.