Antiviral activity of Polygonum aviculare extract against murine norovirus as norovirus surrogate and its application in model food

Norovirus is a major cause of acute gastroenteritis, with vaccines or antiviral therapy yet to be approved. Polygonum aviculare is a medicinal plant with various physiological properties. In this study, the antiviral activity of Polygonum aviculare extract (PAE) was examined against murine norovirus (MNV-1), a human norovirus surrogate. Pre-treatment with PAE suppressed MNV-1, achieving a half-maximal inhibitory concentration (IC₅₀) of 78.4 μg/mL. TEM images revealed viral morphological changes following PAE treatment, indicating the antiviral effect of PAE. Treatment with 100 and 200 μg/mL PAE for 1 h significantly reduced the temperature-dependent antiviral PAE activity at all temperatures. Time-of-addition test results also demonstrated PAE antiviral activity in cell pre-, co-, and post-treatments, with slightly higher activity detected upon cell pre-treatment. HPLC analysis identified avicularin and myricitrin peaks, and LC-QTOF/MS determined phenolic acids and flavonoids as the main constituents. Our findings confirmed the antiviral efficacy of myricetin and quercetin at concentrations of 50 and 100 μM in co-treatment experiments. Upon inoculating the cabbage surface with MNV-1, PAE treatment at 4 or 25 °C reduced MNV-1 plaque formation. Collectively, our findings suggest that PAE could effectively inactivate norovirus and demonstrate promising potential as a natural antiviral agent for food safety.