Nitrostilbenes: Synthesis and Biological Evaluation as Potential Anti-Influenza Virus Agents

Resveratrol (RSV) is a natural stilbene polyphenolic compound found in several plant species. It is characterized by antioxidant properties, and its role in controlling viral replication has been demonstrated for different viral infections. Despite its promising antiviral properties, RSV biological activity is limited by its low bioavailability and high metabolic rate. In this study, we optimized its structure by synthesizing new RSV derivatives that maintained the phenolic scaffold and contained different substitution patterns and evaluated their potential anti-influenza virus activity. The results showed that viral protein synthesis decreased 24 h post infection; particularly, the nitro-containing compounds strongly reduced viral replication. The molecules did not exert their antioxidant properties during infection; in fact, they were not able to rescue the virus-induced drop in GSH content or improve the antioxidant response mediated by the Nrf2 transcription factor and G6PD enzyme. Similar to what has already been reported for RSV, they interfered with the nuclear-cytoplasmic traffic of viral nucleoprotein, probably inhibiting cellular kinases involved in the regulation of specific steps of the virus life cycle. Overall, the data indicate that more lipophilic RSV derivatives have improved antiviral efficacy compared with RSV and open the way for new cell-targeted antiviral strategies.