Identification of Anti-Viral Compounds from Toxicodendron vernicifluum Extract That Inhibit the Coronavirus Replication.

Coronavirus can cause diseases ranging from mild cough to severe COVID-19. Although vaccines and antiviral agents for coronaviruses are available, alternative strategies are still needed to address emerging variants in the future. Toxicodendron vernicifluum is known to be rich in flavonoids, which exhibit antioxidant, anti-inflammatory, anticancer, and antiviral activities. However, the antiviral activity of T. vernicifluum against coronaviruses has not been fully investigated. Here, we report that the T. vernicifluum ethanol extract (TVE) shows antiviral effects against human coronavirus. TVE treatment inhibited coronavirus replication as well as viral infectivity. To elucidate the active constituents responsible for this activity, comprehensive phytochemical profiling of TVE was performed using UPLC-Q-Orbitrap-MS, leading to the tentative identification of major phytochemicals. Based on this analytical profiling, individual compounds were isolated from TVE and evaluated for antiviral activity against coronavirus. We found that ethyl gallate, fisetin, butin, sulfuretin, and gallic acid exhibit antiviral activity against coronavirus.