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

## TL;DR

This study shows that a fungal compound called 6-pentyl-α-pyrone can reduce bovine coronavirus in lab tests, suggesting it might be useful for treating coronaviruses like SARS-CoV-2.

## Contribution

The study introduces a novel fluorescence quantification method and demonstrates the antiviral potential of 6-pentyl-α-pyrone against bovine coronavirus.

## Key findings

- Post-infection treatment with 6-pentyl-α-pyrone reduced viral load and internalization in bovine coronavirus.
- A new fluorescence quantification method showed strong agreement with RT-qPCR results.
- 6-pentyl-α-pyrone was non-cytotoxic and effective under specific experimental conditions.

## Abstract

This study aimed to evaluate the activity of the fungal metabolite 6-pentyl-α-pyrone against bovine coronavirus in vitro. Recently, the COVID-19 crisis has highlighted the urgent need to investigate natural products and their derivatives as potential antiviral drugs. Moreover, bovine coronavirus is closely related to human coronaviruses, and it is often used as a virus model in preliminary antiviral research to avoid handling highly pathogenic human viruses. Herein, it was demonstrated that 6-pentyl-α-pyrone presents antiviral activity against bovine coronavirus under specific conditions, and further research is recommended to clarify its potential in coronavirus therapeutics.

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 Betacoronavirus 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.