Advances in developing small molecule SARS 3CL(pro) inhibitors as potential remedy for corona virus infection

Originated in China, coronavirus disease 2019 (COVID-19)- the highly contagious and fatal respiratory disease caused by SARS-CoV-2 has already infected more than 29 million people worldwide with a mortality rate of 3.15% (according to World Health Organization’s (WHO’s) report, September 2020) and the number is exponentially increasing with no remedy whatsoever discovered till date. But it is not the first time this infectious viral disease has appeared, in 2002 SARS-CoV infected more than 8000 individuals of which 9.6% patients died and in 2012 approximately 35% of MERS-CoV infected patients have died. Literature reports indicate that a chymotripsin-like cystein protease (3CL(pro)) is responsible for the replication of the virus inside the host cell. Therefore, design and synthesis of 3CL(pro) inhibitor molecules play a great impact in drug development against this COVID-19 pandemic. In this review, we are discussing the anti-SARS effect of some small molecule 3CL(pro) inhibitors with their various binding modes of interactions to the target protein.