Influenza A virus-IN-1, a dihydropyrrolidones derivative, is a highly effective inhibitor of various subtypes of influenza A virus (IAV) with IC 50 values ranging from 3.11 μM to 7.13 μM. It effectively suppresses IAV replication and enhances the expression of key antiviral cytokines, such as IFN-β, and the antiviral protein MxA.

A/PR/8/34 (H1N1) with NA-H274Y:6.48 μM (IC50), Influenza A virus 690 (H3):7.13 μM (IC50), A/FM-1/1/47 (H1N1):3.58 μM (IC50), A/Aichi/2/68 (H3N2):5.26 μM (IC50), A/Puerto Rico/8/34 (H1N1):3.11 μM (IC50)

Treatment with Influenza A virus-IN-1 (compound 5-2; concentrations ranging from 5-40 μM; for 24 hours; in MDCK cells) notably diminishes the yield of influenza viral nucleoprotein (NP) and the expression level of NP protein in a dose-dependent manner. Additionally, this compound lowers influenza hemagglutinin (HA) mRNA expression at all assessed time points. It effectively hampers Influenza A virus (IAV) replication and curtails the production of NDAPH oxidase NOX1 in MDCK cells. Western Blot analysis conducted on IAV-infected MDCK cells treated with varying concentrations (5 μM, 10 μM, 20 μM, 40 μM) for 24 hours corroborates the significant reduction in influenza viral NP yields, evidencing a dose-responsive effect.