<i>Cornus officinalis</i> extracts and fractions exhibit multi-targeting antiviral activity against influenza A virus <i>in vitro</i>

Influenza virus infection remains a significant public health threat, causing epidemics and pandemics.The rise of drugresistant strains and adverse effects linked to current antiviral treatments underscore the need for the development of novel antiviral agents.In this study, we explored the antiviral potential of extracts and organic solvent fractions derived from Cornus officinalis Sieb.et Zucc.(CO) against influenza A viruses in vitro.The noncytotoxic concentration range of the CO extracts and fractions was measured by in vitro cytotoxicity assay.CO extracts demonstrated strong virucidal activity against influenza A virus at noncytotoxic concentrations.The extracts inhibited influenza viral entry and release steps by targeting viral surface hemagglutinin (HA) and neuraminidase (NA) proteins.This multi-target antiviral action was further confirmed by time-of-addition experiments and cytopathic effect reduction assay.Organic solvent fractions of the CO water extract also displayed significant virucidal effects and NA inhibition against influenza A virus.Of the four solvent fractions, ethyl acetate and butanol fractions exhibited the most potent virucidal activity.While none of the fractions demonstrated HA inhibition, all showed substantial NA inhibition, with chloroform and butanol fractions displaying strong activity, yielding IC 50 values of 1.5 g/mL and 5.4 g/mL, respectively.The findings demonstrate that CO extracts and organic solvent fractions exhibit multi-target antiviral effects against influenza A viruses.These results suggest that CO offers promising avenues for the development of novel antiviral therapeutics against influenza A infections.