Identification of Diphenoxylate as an Antiviral Agent Against Severe Acute Respiratory Syndrome Coronavirus 2

This is the first report to show that diphenoxylate is highly active against SARS-CoV-2 with EC 50 of 1.4 μM, CC 50 over 100 μM and selectivity index over 71.4 after screening of 14 diphenyl derivatives. Our results with highly purified solid diphenoxylate confirmatively demonstrate that the viral S protein is reduced in the virus-infected cells in a dose-dependent manner. It could provide insights for antiviral treatment of COVID-19 with diphenoxylate or its chemical derivatives