Phytocompounds of Rheum emodi, Thymus serpyllum, and Artemisia annua Inhibit Spike Protein of SARS-CoV-2 Binding to ACE2 Receptor: In Silico Approach.

COVID-19, the disease caused by SARS-CoV-2, has been declared as a global pandemic. Traditional medicinal plants have long history to treat viral infections. Our in silico approach suggested that unique phytocompounds such as emodin, thymol and carvacrol, and artemisinin could physically bind SARS-CoV-2 spike glycoproteins (6VXX and 6VYB), SARS-CoV-2 B.1.351 South Africa variant of Spike glycoprotein (7NXA), and even with ACE2 and prevent the SARS-CoV-2 binding to the host ACE2, TMPRSS2 and neutrapilin-1 receptors. Since Chloroquine has been looked as potential therapy against COVID-19, we also compared the binding of chloroquine and artemisinin for its interaction with spike proteins (6VXX, 6VYB) and its variant 7NXA, respectively. Molecular docking study of phytocompounds and SARS-CoV-2 spike protein was performed by using AutoDock/Vina software. Molecular dynamics (MD) simulation was performed for 50ns. Among all the phytocompounds, molecular docking studies revealed lowest binding energy of artemisinin with 6VXX and 6VYB, with E_total -10.5 KJ mol^-1 and -10.3 KJ mol^-1 respectively. Emodin showed the best binding affinity with 6VYB with E_total -8.8 KJ mol^-1and SARS-CoV-2 B.1.351 variant (7NXA) with binding energy of -6.4KJ mol^-1. Emodin showed best interactions with TMPRSS 2 and ACE2 with E_total of -7.1 and -7.3 KJ mol^-1 respectively, whereas artemisinin interacts with TMPRSS 2 and ACE2 with E_total of -6.9 and -7.4 KJ mol^-1 respectively. All the phytocompounds were non-toxic and non-carcinogenic. MD simulation showed that artemisinin has more stable interaction with 6VYB as compared to 6VXX, and hence proposed as potential phytochemical to prevent SARS-CoV-2 interaction with ACE-2 receptor.

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Supplementary information: The online version contains supplementary material available at 10.1007/s40495-021-00259-4.