Antiviral effects of Codonopsis pilosula extract and its bioactive components against porcine epidemic diarrhea virus in vitro via the AMPK/mTOR pathway

BACKGROUND: Porcine Epidemic Diarrhea Virus (PEDV) frequently outbreaks across China, posing a significant economic threat to the swine industry. PEDV exhibits a high degree of variability and is associated with a high mortality rate in piglets. Currently, vaccines show limited efficacy against variant strains, making it critical to explore alternative treatments, particularly the potential of traditional Chinese medicine (TCM) in combating PEDV infection. RESULTS: This study aims to elucidate the antiviral mechanisms of Codonopsis pilosula (Dangshen) aqueous extract and its bioactive components, with a particular focus on the relationship between autophagy and antiviral effects, thereby providing theoretical support for the clinical application of TCM in treating PEDV infection. In this study, different concentrations of Codonopsis aqueous extract (1.25 mg/mL, 2.5 mg/mL, and 5 mg/mL) were applied to PEDV-infected IPEC-J2 cells. The results demonstrated that cells treated with the high-dose group exhibited well-preserved cellular structure, with minimal organelle damage. Furthermore, the high-dose treatment significantly reduced the expression of PEDV N, LC3, AMPK, and p-AMPK proteins in the infected cells. Additionally, it modulated the expression of key regulators in the AMPK/mTOR pathway, including mTOR, while upregulating the expression of AMPK and ATG13 mRNA. Moreover, five bioactive components of Codonopsis including β-sitosterol (SITO), quercetin (Que), 5-hydroxymethylfurfural (HMF), apigenin (APG), and nicotinic acid (NA), significantly decreased both the mRNA and protein expression of PEDV N and LC3. APG exhibits the strongest combined antiviral and anti-autophagic effects. SITO, QUE, APG, and NA reduced AMPK expression. QUE increased ATG13 levels, whereas the other four bioactive components significantly decreased ATG13 expression. CONCLUSIONS: Therefore, Codonopsis aqueous extract and its bioactive components can alleviate pathological damage in IPEC-J2 cells, inhibit PEDV replication, and modulate the expression of genes and proteins associated with the AMPK/mTOR pathway. This study provides new theoretical evidence for the potential clinical application of Codonopsis in the treatment of PEDV infection.