The Anti-PEDV Effects and Mechanisms of Forsythia Essential Oil Based on Network Pharmacology and Experimental Validation

Objective: Porcine epidemic diarrhea virus (PEDV), a member of the Coronaviridae, is responsible for acute diarrhea, vomiting, and dehydration, which can lead to high mortality in neonatal piglets. Previous research has indicated the antiviral potential of forsythia essential oil (FEO); however, its active components and mechanisms of action remain inadequately defined. This study aims to investigate the antiviral effects of FEO and elucidate its potential mechanisms for treating PEDV. Methods: The primary components of FEO were identified using gas chromatography-mass spectrometry (GC/MS) in conjunction with the National Institute of Standards and Technology Standard Spectrum (NIST) Database. Network pharmacology and weighting coefficients were employed to determine the key signaling pathways associated with PEDV-related diseases. Molecular docking simulations were conducted to explore the interactions between the active ingredients and their corresponding targets. The safety profile of FEO was assessed through cell viability assays utilizing the CCK8 method. Subsequently, immunofluorescence assays (IFA) and reverse transcription-quantitative polymerase chain reaction (RT-Q-PCR) were performed to provide evidence of the anti-PEDV effects. Additionally, the viral replication cycle was analyzed to identify the stages at which FEO exerts its antiviral effects. Finally, key targets were validated through RT-Q-PCR to further investigate the anti-PEDV mechanisms of FEO. Results: The IL-17 signaling pathway was identified as a critical pathway for the treatment of PEDV with FEO based on network pharmacology and weighting coefficient analyses. Furthermore, results from RT-Q-PCR and IFA demonstrated that FEO influenced the replication of PEDV during the attachment and internalization phases. Specifically, during the viral attachment phase, FEO significantly upregulated the expression of HSP90AA1 while downregulating MAPK14 expression, leading to a reduction in associated inflammatory factors. At the high dose of FEO, the expression of HSP90AA1 was higher than that of the model group by about 5-fold, and the expression of MAPK14 was lower than that of the model group by about 2-fold. Cell viability assay showed no significant cytotoxicity of FEO at 0.63 μL/mL, thus confirming its safety. Conclusion: The findings of this study suggest that FEO possesses potential antiviral properties against PEDV. Its novel mechanisms of action warrant further investigation, which may contribute to the development of effective therapeutic strategies for managing PEDV infections.