https://www.sciencedirect.com/science/article/pii/S0168170220310832?v=s5

• Plant derived toxin
• Used at low concentration to treat hypertension and cardiac arrhythmia
• Shown to inhibit SARS-2 and MERS replication in the nanomolar range
• Inhibit NA+ K+ pump
• A low dose can reduce inflammatory cytokine production in LPS treated rats: blocks nuclear translocation of NF-kB
• Can also promote interaction between the pump and AT1R and this receptor interacts directly with ACE2
• Potential con: very toxic at high doses
• Theory: very low concentrations of ouabain (possible digoxin) can cause the internalization of the pump in complex with AT1R and ACE2 reducing the cell surface expression levels of ACE2 hence preventing SARS-2 to enter the cell