Discovery and SAR Research for Antivirus Activity of Novel Butenolide on Influenza A Virus H1N1 In Vitro and In Vivo

Influenza viruses (IV) cause substantial morbidity and mortality through routine seasonal spread and epidemics. A novel series of butenolides were discovered to be able to inhibit influenza H1N1 activity in vitro, and the SAR for anti-influenza activity was investigated. By optimization of the hit compound, compound 37 was obtained with an EC50 of 6.7 μM against influenza A virus H1N1 as an inhibitor of NA and with low cytotoxicity on MDCK cells. Also, it can inhibit the expression of the influenza A virus gene in the lung of SPF KM mice to show antivirus activity in vivo. These results suggested that compound 37 could inhibit the influenza A virus H1N1 via targeting NA.