Discovery of Some Antiviral Natural Products to Fight Against Novel Coronavirus (SARS-CoV-2) Using an In silico Approach

Background: Novel coronavirus is a type of enveloped viruses with a single-stranded RNA enclosing helical nucleocapsid. The envelope consists of spikes on the surface which are made up of proteins through which virus enters into human cells. Until now, there is no specific drug or vaccine available to treat COVID-19 infection. In this scenario, reposting of drug or active molecules may provide rapid solution to fight against this deadly disease. Objective: We selected 30 phytoconstituents from the different plants which are reported for antiviral activities against coronavirus (CoVs) and performed in silico screening to find out phytoconstituents which have potency to inhibit specific target of the novel coronavirus. Methods: We performed molecular docking studies on three different proteins of novel coronavirus, namely COVID-19 main protease (3CL pro), papain-like protease (PL pro) and spike protein (S) attached to ACE2 binding domain. The screening of the phytoconstituents on the basis of binding affinity compared to standard drugs. The validations of screened compounds were done using ADMET and bioactivity prediction. Results: We screened five compounds biscoclaurine, norreticuline, amentoflavone, licoricidin and myricetin, using in silico approach. All compounds were found safe in In silico toxicity studies. Bioactivity prediction reveals that these compounds may act through protease or enzyme inhibition. Results of compound biscoclaurine norreticuline were more interesting as this biscoclaurine had higher binding affinity for the target 3CLpro and PLpro targets and norreticuline had a higher binding affinity for the target PLpro and Spike protein. Conclusion: Our study concludes that these compounds could be further explored rapidly as it may have potential to fight against COVID-19.