Naturally occurring anthraquinones as potential inhibitors of SARS-CoV-2 main protease: an integrated computational study

The novel coronavirus disease (COVID-19) has spread throughout the globe, affecting millions of people. The World Health Organization (WHO) has declared this infectious disease a pandemic. At present, several clinical trials are going on to identify possible drugs for treating this infection. SARS-CoV-2 M-pro is one of the most critical drug targets for the blockage of viral replication. The aim of this study was to identify potential natural anthraquinones that could bind to the active site of SARS-CoV-2 main protease and stop the viral replication. Blind molecular docking studies of 13 anthraquinones and one control drug (Boceprevir) with SARS-CoV-2 M-pro were carried out using the SwissDOCK server, and alterporriol-Q that showed the highest binding affinity towards M-pro were subjected to molecular dynamics simulation studies. This study indicated that several antiviral anthraquinones could prove to be effective inhibitors for SARS-CoV-2 M-pro of COVID-19 as they bind near the active site having the catalytic dyad, HIS41 and CYS145 through non-covalent forces. The anthraquinones showed less inhibitory potential as compared to the FDA-approved drug, boceprevir. Among the anthraquinones studied, alterporriol-Q was found to be the most potent inhibitor of SARS-CoV-2 M-pro. Further, MD simulation studies for M-pro-alterporriol-Q system suggested that alterporriol-Q does not alter the structure of M-pro to a significant extent. Considering the impact of COVID-19, identification of alternate compounds like alterporriol-Q that could inhibit the viral infection will help in accelerating the process of drug discovery.

Automated summary

This study aimed to identify potential natural anthraquinones that could bind to the active site of SARS-CoV-2 main protease and stop viral replication. The results showed that several antiviral anthraquinones could be effective inhibitors for SARS-CoV-2 main protease of COVID-19. Among the anthraquinones studied, alterporriol-Q was found to be the most potent inhibitor.