Docking Studies of Usnic Acid and Sodium Usnate on SARS CoV-2 Main Protease and Spike Protein RBD

SARS CoV-2 a pandemic influenza like infectious disease emerged in December 2019 has spread throughout the world within few months. Scientists are trying their best to find medicine and vaccine. Usnic acid and its derivatives as herbal supplements are widely used as mouth wash, cosmetics, antiviral agents. In this study, usnic acid and its derivative-sodium usnate in comparison with favipiravir are docked with main protease and spike protein RBD 6M0J of SARS Cov-2. Usnic acid and sodium usnate exhibit better binding affinities for main protease and spike RBD. The data has been compared with favipiravir. Favipiravir, usnic acid, sodium usnate shows binding affinity of -4.25, -8.05 and -8.55 kcal/mol respectively with main protease. While favipiravir, usnic acid and sodium usnate exhibit binding affinities of -4.25, -6.02 and -6.53 kcal/mol with spike RBD respectively. One of the interesting features is that the inhibition constant values of usnic acid is 1.27 µM and sodium usnate is 539.86 nM in comparison to favipiravir (764.13 µM) with main protease.