In Vitro Antiviral Activity of the Fungal Metabolite 6-Pentyl-α-Pyrone Against Bovine Coronavirus: A Translational Study to SARS-CoV-2.

The recent COVID-19 pandemic has prompted the scientific community to prioritize the discovery of preventive methods and new therapeutics, including the investigation of natural compounds with antiviral potential. Fungal secondary metabolites (SMs) represent a promising source of antiviral drugs due to their structural diversity and intrinsic biocompatibility. Herein, the antiviral activity of 6-pentyl-α-pyrone (6PP) against bovine coronavirus (BCoV) has been evaluated in vitro. Considering that BCoV and SARS-CoV-2 are both members of the genus and share several key features, BCoV represents a valuable reference model for human coronavirus research. A non-cytotoxic dose of 6PP was used on MDBK cells to evaluate its antiviral activity against BCoV. Different experimental conditions were employed to examine cell monolayer protection both pre- and post-infection, as well as the potential inhibition of viral internalization. Overall, post-infection 6PP treatment reduced viral load and decreased viral internalization. Results were analyzed using viral titration and quantitative PCR, while data interpretation was performed by statistical software tools. This study presents a novel fluorescence quantification approach with high confidence demonstrated by its significant concordance with RT-qPCR results. These data suggest that 6PP could be an effective antiviral agent for BCoV, warranting further investigation of its role in coronavirus inhibition.