Saquinavir is an antiretroviral inhibitor of the human immunodeficiency virus. It potently inhibits HIV-1 (Ki=0.12nM) and HIV-2 (Ki<0.1nM) protease in vitro. HIV-1 protease is important for the replication of the virus within the cell and the release of mature viral particles from the infected cell. Formulations containing saquinavir have been used in combination with other inhibitors for the treatment of AIDS. Saquinavir shows other antimicrobial and antiviral activity. Potential SARS-CoV-2 replication inhibitor, responsible for COVID-19. Shows anti-cancer activity. Shown to induce apoptosis, autophagy and endoplasmic reticulum stress, which consequently leads to cancer cell death. Anti-inflammatory agent. Blocks cathepsin V and thereby inhibits disulfide HMGB1-induced TLR4 activation and cytokine production.