Flavonoids Antiviral Effects: Focusing on Entry Inhibition of Influenza and Coronavirus

Influenza and coronavirus pneumonia have caused a significant healthcare burden globally, raising growing concerns. The crisis and burden on public health have prompted an urgent need to find and develop medications to reduce the destructive effects of these diseases. Recently, there has been intense interest in evaluating the potential benefits of herbal drugs for managing viral infections. Due to their antioxidant, anti-mutagenic, anti-inflammatory, and anti-cancer effects, flavonoids appear to be promising agents for treating patients infected with viruses. In the field of natural medicine, the inhibitory role of flavonoids in the fusion and entry of different viruses may offer a hopeful contribution against influenza and coronavirus. Therefore, in this review, we discuss the pathogenesis of influenza and coronavirus and the role of flavonoids during infection, focusing on how they prevent the attachment and entry of viruses into host cells. In this regard, we have summarized the most recent related literature to provide valuable information about the effects of flavonoids on virus-host fusion, virus entry, and other related downstream mechanisms. We hope that these natural compounds will be suitable and safe adjuncts to other therapeutic drugs and approaches.