Polyphenols have been extensively studied for their antiviral effects against respiratory virus infections. In this study, we evaluated the antiviral activity of polydatin (resveratrol glycoside) and a mixture of polyphenols and other micronutrients, named A5+ (SIRT500 Plus), against influenza virus and SARS-CoV-2 infections.

To this end, we infected Vero E6 cells and analyzed the replication of both respiratory viruses in terms of viral protein synthesis and viral titration. We demonstrated that A5+ showed greater efficacy in inhibiting both influenza virus and SARS-CoV-2 infections compared to polydatin alone. In fact, post-infection treatment significantly reduced viral protein expression and viral release, likely by interfering with any stage of the viral replication cycle.

Interestingly, treatment with A5+ significantly reduced IL-6 cytokine production in influenza virus-infected cells, suggesting its potential anti-inflammatory properties during infection. Overall, these results demonstrate the synergistic and innovative antiviral efficacy of the A5+ mixture, although