Background: The evolution of the pandemic has burdened the national healthcare systems worldwide
and at present, there is no preferred antiviral treatment for COVID-19. Recently, the SARS-Cov-2 protease
structure was released that may be exploited in in-silico studies in order to conduct molecular docking analysis.
Methods: In particular, we compared the binding of twoantimalarial drugs, already in use, (i.e. chloroquine and
hydroxychloroquine), which showed some potential clinical effects on COVID-19 patients, using ritonavir, lopinavir
and darunavir as positive control tree antiviral recognized compounds.
Results: Our results showed that hydroxychloroquine but not chloroquine exhibited a significant binding activity
to the main protease similar to that possessed by protease inhibitors tested for other viral infections.
Conclusion: Our data suggest that hydroxychloroquine may exert additional direct antiviral activity compared
to chloroquine. In the absence of clinical studies comparing the efficacy of these two compounds, hydroxychloroquine
may offer additional effects and may be considered as the first choice.