Activity of isatine-sulfadimidine derivatives against 2009 pandemic H1N1 influenza virus in cell culture

Background: The development of antiviral drugs has provided crucial new means to mitigate or relieve the debilitating effects of many viral pathogens. New classes of inhibitors are essential to combat swine influenza viral infection. Methods: A series of isatine-sulfadimidine derivatives were screened for antiviral activity against swine influenza A/California/07/2009 (H1N1) virus in Madin–Darby canine kidney (MDCK) cell culture. Cytotoxicity of the synthesized compounds was also tested in uninfected MDCK cells. Results: All the compounds inhibit the influenza A (H1N1) in MDCK cells. The most active compounds, SPIII-5Br and SPIII-5H, inhibited virus-induced cytopathology by 50% at 27 and 30 μM, respectively, with 50% cytotoxicity occurring at a much higher dose (975–1,000 μM). The positive control compound ribavirin inhibits the replication of the virus at 18 μM and cytotoxic concentration was found to be >1,000 μM. Conclusions: SPIII-5Br and SPIII-5H exhibited potency in the same range as ribavirin and are suitable candidate molecules for further investigation.