Folium Isatidis suppresses PCV2 replication and alleviates PCV2-induced lung injury by modulating the PI3K/AKT signaling pathway and TNF-α activity

Background Folium Isatidis (Da Qing Ye), a traditional Chinese medicine, exhibits broad-spectrum antiviral and immunomodulatory properties and has been widely used in treating respiratory diseases. Porcine circovirus type 2 (PCV2), a widespread swine virus, causes respiratory disease complex in piglets and leads to substantial economic losses in the global swine industry. This study aimed to evaluate the anti-PCV2 activity of Folium Isatidis . Materials and methods The anti-PCV2 activity of Folium Isatidis was first validated through both in vivo and in vitro experiments. Potential targets of Folium Isatidis were identified using TCMSP, BATMAN-TCM, and SwissTargetPrediction databases, and intersected with PCV2-related targets. Mechanism exploration involved PPI network analysis, GO annotation, and KEGG enrichment. Molecular docking analyzed component-target interactions, followed by experimental validation of the core component. Finally, the anti-PCV2 effect of the core component was verified through in vitro and in vivo experiments. Results A total of 135 overlapping targets between Folium Isatidis components and PCV2-related disease targets were identified. Key targets, including AKT1 and TNF-α, were implicated in the therapeutic effects of Folium Isatidis against PCV2. Isovitexin was identified to be the core component that directly binds to AKT1 and TNF-α, thereby inhibiting the PI3K/AKT signaling pathway and regulating TNF-α expression and activity to suppress PCV2 replication and alleviate PCV2-induced lung injury. Conclusions Our study reveals that Isovitexin, the core anti-PCV2 component of Folium Isatidis , exerts its effect by inhibiting the PI3K/AKT pathway and modulating TNF-α, thereby outlining a novel therapeutic strategy for combating PCV2 infection and associated respiratory injuries.