Carthamus tinctorius L. is widely used in traditional Chinese medicines for the treatment of cardiovascular disease. However, our current understanding of the molecular mechanisms supporting its clinical application still lags behind. In this study, a systems pharmacology approach integrating drug-likeness evaluation, oral bioavailability prediction, target exploration, GO enrichment analysis, KEGG pathway performance and network construction was adopted to explore its therapeutic mechanism. A total of 21 active ingredients contained in Carthamus tinctorius L. and 113 major proteins were screened out as effective players in the treatment of cardiovascular disease through some related pathways. And the association among the active ingredients, major hubs and main pathways was investigated, implying the potential biological progression of Carthamus tinctorius L. acting on cardiovascular disease. Importantly, the majority of hubs and pathways were found to be highly related with platelet activation process. Core genes that can be regulated by Carthamus tinctorius L. in platelet activation pathway were PRKACA, PIK3R1, MAPK1, PPP1CC, PIK3CA and SYK, and they may play a central role in suppressing platelet aggregation. The systems pharmacology approach used in this study may provide a feasible tool to clarify the mechanism of traditional Chinese medicines and further develop their therapeutic potentials.

Topiroxostat is a selective xanthine oxidoreductase (XOR) inhibitor for the management of hyperuricemia in patients with or without gout. In this work, we aim to employ the physiologically based pharmacokinetic (PBPK) model with the drug-target residence time model to predict and characterize both the pharmacokinetics (PK) and pharmacodynamics (PD) of topiroxostat in humans. The plasma concentration-time profile of topiroxostat was simulated based on drug properties and human physiology parameters. The predictive power of this PBPK model was then demonstrated by comparison of stimulated to observed pharmacokinetic parameters. The utility of the model was further demonstrated through predicting the oral absorption and disposition characteristics of topiroxostat in humans. Finally, by combining the PBPK model and the drug-target residence time model, we successfully predicted the target occupancy and built the relationship between PK and PD using in vitro, in vivo and in silico information. The results showed that topiroxostat exhibited significant in vivo pharmacological activity even after the complete clearance of this drug from the liver (target site), which may be due to the long residence time of the binary topiroxostat-XOR complex. This work may be helpful to guide future investigations of topiroxostat and also provides a novel strategy for PK/PD studies.