Background: The current pandemic outbreak of COVID-19 due to viral infections by SARS-CoV-2 is now
become associated with severe commotion on global healthcare and economy.
Objective: In this extreme situation when vaccine or effective new drugs against COVID-19 are not available, the only
quick and feasible therapeutic alternative would be the drug repurposing approach.
Method: In the present work, in silico screening of some antiviral and antiprotozoal drugs was performed based on docking
Results: Two known antiviral drugs sorivudine and noricumazole B are predicted to bind to the active site of the viral
proteases namely cysteine like protease or 3CL protease (3CLpro) and papain like protease (PLpro) respectively with a
highly favorable free energy of binding. Further, the promising molecules were subjected for checking their activity on other
molecular targets in SARS-CoV-2 like spike protein S1, RNA dependent RNA polymerase (RdRp) and angiotensin
converting enzyme 2 (ACE2) receptor. But the compounds were found non-effective on rest other molecular targets.
Conclusion: Sorivudine alone or a combination of sorivudine and noricumazole B may be administered to impede viral
replication though the predicted drug likeliness of noricumazole B is not very much satisfactory. These observations are
solely based on the results from blind docking with protein molecules and that need to be further corroborated with