Antiviral activity of soybean GL 2626/96 (Glycine max) ethanolic extract against influenza A virus in vitro and in vivo

Influenza viruses cause respiratory infections in humans with high morbidity and mortality rates. Neuraminidase inhibitors such as oseltamivir and peramivir are the most commonly used drugs for influenza virus infections. However, the emergence of resistant viruses necessitates the urgent need to develop next-generation anti-influenza drugs. Soybean (Glycine max L. Merr.) is widely cultivated and used as food worldwide. In addition, soybean has long been used as a nutritional supplement and herbal medicine. However, the potential anti-influenza properties of the soybean cultivar “GL 2626/96″ (SG2626) are yet to be investigated. Herein, we determined whether the ethanolic extract of SG2626 (SG2626E) has anti-viral activity through performing SG2626E pre-, co-, and post-treatment assays, using the influenza green fluorescent protein (GFP)-tagged influenza A/PR/8/34 (A/PR/8/34-GFP) virus. SG2626E showed anti-influenza virus activity in pre- and co-treated cells in a dose-dependent manner, but not in post-treated cells. SG2626E imparted a considerable inhibitory effect on influenza A virus (IAV) infection through blocking viral attachment. SG2626E inhibited the activity of viral hemagglutinin, but not viral neuraminidase of the IAV. SG2626E inhibited IAV infection by reducing intracellular calcium levels in infected human lung epithelial A549 cells. Additionally, SG2626E reduced body weight loss, decreased mortality, and increased the survival rate through reducing viral replication in the lungs of IAV-infected mice. Overall, these results suggest that SG2626E inhibits IAV infection and is a potential novel anti-influenza agent. [Display omitted] •SG2626E inhibited IAV infection by blocking viral entry and being virucidal.•SG2626E inhibited hemagglutinin activity of IAV.•SG2626E reduced weight loss and decreased mortality in IAV-infected mice.