Therapeutic potential of natural alkaloid emetine against emerging COVID-19 and future viral pandemics

The outbreak of COVID-19 pandemic caused by the infection of SARS-CoV-2, has become a global crisis, threatening public health and disrupting global economy. Until now, effective therapeutics against COVID-19 and other coronavirus diseases are in high demand. Several antiviral strategies of drug discovery have identified many small molecules with potent anti-COVID-19 activity. Emetine, one of the main alkaloids of Carapichea ipecacuanha, has been found to exhibit potent antiviral activity against SARS-CoV-2, and other human coronaviruses, multiple RNA and DNA viruses at low nanomolar concentrations in different cell lines. In silico analysis reveals that emetine directly disrupts the activities of SARS-CoV-2 S-protein with host ACE2, and of RdRp-, 3CL-, PL-,and N- proteins. Moreover, emetine shows potent anti-inflammatory and anti-pulmonary arterial hypertensive properties by down-regulating the ERK1/2, NF-κB and RhoA/Rho-kinase/CyPA/Bsg signaling pathways. At low doses, emetine is effective for treatment of COVID-19 patients and other viral infections in rodents. This review discusses the current findings on the antiviral efficacy of emetine against the emerging SARS-CoV-2 and other corona, RNA and DNA viruses, as well as its immunoregulatory pathways and clinical potential in COVID-19 infection for its development as antiviral prodrugs to treat current COVID-19 and future viral pandemics.