GC-376 is primarily used as a potent inhibitor of proteases, particularly targeting the main protease (Mpro) of coronaviruses. Its application is significant in antiviral research, where it is studied for its potential to treat infections caused by viruses such as SARS-CoV-2, the virus responsible for COVID-19. By inhibiting the viral protease, GC-376 prevents the virus from replicating, making it a promising candidate for antiviral therapy. Additionally, it is utilized in biochemical studies to understand the mechanisms of viral protease function and inhibition, aiding in the development of new therapeutic strategies against viral diseases.