Screening of effective parts of She Medicine Xiaoxianggou and studying its mechanism in the treatment of gouty arthritis
Authors: Huang Yulong , Lin Xiaohui , Lin Minhua , Aikebaier Reheman , Wang Yujia , Zhong Di , Xiao Bingying , Zhang Jiangyuan , Zhang Lingling , Chen Zichun , Nie Xuekun 
Published: February 2024

Abstract
The prevalence of gouty arthritis has been steadily rising over recent years, with a trend towards an earlier onset. Currently, the main drugs used in clinical practice for the treatment of gouty arthritis include non-steroidal anti-inflammatory drugs and glucocorticoids. However, these drugs come with certain limitations, including low efficacy, side effects, and a high risk of palindromia. Xiaoxianggou, a traditional medicine, is derived from the dried roots and stems of Ficus pandurata Hance var. angustifolia Cheng or Ficus pandurata Hance var. holophylla Migo. It has properties such as wind elimination, dampness removal, heat-clearing, and detoxification. Notably, Xiaoxianggou exhibits a superior therapeutic effect on gout arthritis, although its mechanism of action remains unclear. Objective To investigate the extraction process of Xiaoxianggou and improve its potential as a treatment for GA, it is essential to screen the active site and validate its effectiveness through cellular and animal studies to explore its potential mechanism. Method The ultrasonic-assisted extraction of total phenols from Xiaoxianggou was optimized using an orthogonal experimental design. The MTS method was employed to determine the optimum concentration of the anti-inflammatory drug in Xiaoxianggou. ELISA was utilized to assess the levels of IL-1β and TNF-α in a macrophage inflammation model and synovial tissue of rats. The therapeutic effect of Xiaoxianggou's ethyl acetate fraction on GA rats was evaluated based on joint swelling and gait behavior scores. Joint tissue pathologies in GA rats were observed through hematoxylin-eosin (HE) staining. The main chemical components of Xiaoxianggou's ethyl acetate fraction were analyzed using HPLC-MS/MS technology. The network pharmacology approach was employed to identify potential signaling pathways associated with the treatment of GA using Xiaoxianggou's ethyl acetate fraction. TLR4/MYD88 pathway-related mRNA expression in the RAW264.7 cell inflammatory model treated with Xiaoxianggou's ethyl acetate fraction was determined using real-time fluorescence quantitative PCR. Result The optimal extraction conditions for total phenols from Xiaoxianggou were determined to be a temperature of 70 ℃, an ethanol volume fraction of 60%, and a material-liquid ratio of 1:30. The ethyl acetate effective part of Xiaoxianggou demonstrated the ability to decrease the expression of TNF-α in RAW264.7 cells. Furthermore, it was found that Xiaoxianggou ethyl acetate effective part can reduce the expression of TNF-α and IL-1β in rats suffering from gouty arthritis, while also improving the histopathological structural changes in joint synovium. Moreover, the ethyl acetate effective parts of Xiaoxianggou reduced the mRNA expression of genes associated with the TLR4/MYD88 pathway in inflammatory cell models of RAW264.7. Conclusion The effective component of ethyl acetate, Xiaoxianggou, exhibits a specific therapeutic effect on GA. Its mechanism of action is correlated with the TLR4/MYD88 signaling pathway.