Paeonol Inhibits the Replication of Bovine Herpesvirus Type 1 In Vitro Through Regulating the PI3K/AKT Pathway.

The bovine herpesvirus type I (BHV-1) is a significant pathogen that poses a threat to the healthy development of the cattle industry and has a global prevalence. Paeonol is a phenolic constituent extracted from the dried root bark of peony in the buttercup family. Although paeonol has anti-inflammatory and antioxidant effects, its antiviral capacity remains unclear. Here, we conducted a cytotoxicity assay to screen the safe concentration of the paeonol using bovine turbinate (BT) cells as a model. Antiviral studies showed that paeonol inhibited BHV-1 gB gene and VP8 protein expression, and reduced cytopathic effect and viral titer. Furthermore, paeonol also demonstrated a potent effect on BHV-1 replication with an EC of 18.54 μg/mL and a Selectivity Index (SI) of 28.64. Mechanistic analysis revealed that the PI3K/AKT pathway might be involved in the antiviral mechanism of paeonol. Molecular docking combined with western blot assay further confirmed that paeonol was able to bind stably to the active sites of PI3K and AKT proteins, and significantly inhibited the activation of PI3K/AKT pathway. Interestingly, 740Y-P (a PI3K/AKT pathway agonist) significantly attenuated the anti-BHV-1 effect of paeonol. The above experiments are the first to confirm the inhibitory effect of paeonol on BHV-1 replication, which not only adds evidence to the biological function of paeonol as an antiviral agent, but also lays the foundation for the prevention and control of this disease and the development of feed additives.