System pharmacology analysis to decipher the effect and mechanism of active ingredients combination from herb couple on rheumatoid arthritis in rats

Traditional herb couple Angelicae pubescentis radix (APR) and Notopterygii rhizoma et radix (NRR), composition of two traditional Chinese medicinal herbs, has been used clinically in China for the treatment of rheumatoid arthritis (RA) over years. APR and NRR contain coumarins and phenolic acids, which have been reported to have analgesic and anti-inflammatory activities.The active ingredients combination (AIC) and potential therapeutic mechanism of APR and NRR (AN) herb couple remain unclear. Therefore, the present study aimed to identify the AIC and elucidate the underlying mechanism of AIC on RA.Firstly, a novel strategy of in vitro experiments, computational analysis, UPLC-QTOF-MS and UPLC-QQQ-MS was established to confirm the optimum ratio of AN herb couple samples and identified the AIC. Then, the anti-arthritis effects of the optimal herb couple and AIC were studied with Collagen II induced rheumatoid arthritis (CIA) rats in vivo. Finally, an integrated model of network pharmacology, metabolomics, gut microbiota analysis and biological techniques were applied to clarify the underlying mechanism through a comprehensive perspective.AN7:3 herb couple was regarded as the optimal ratio of AN herbal samples, and AIC was screened as osthole, columbianadin, notopterol, isoimperatorin, psoralen, xanthotoxin, bergapten, nodakenin and bergaptol respectively. Additionally, AIC exerted similar therapeutic effects as AN 7:3 in CIA rats. Moreover, AIC ameliorated RA might via regulating MAPK signaling pathway, altering metabolic disorders and gut microbiome involved autoimmunity.our findings provided scientific evidence to support that AIC of AN herb couple could be used as a prebiotic agent for RA. Importantly, this research provided a systematic and feasible strategy to optimize the proportion of medicinal materials and screen AIC from multi-component traditional Chinese herb couples or Chinese medicine formulae. Moreover, it provided a comprehensive perspective to discover AIC, clarify the overall effects and understand the mechanisms for natural products through the perspective of database and multi-omics integration.