Terpenoids from Centella asiatica, a novel inhibitor against RNA-dependent-RNA polymerase activity of NSP12 of the SARS CoV-2 (COVID-19)

Abstract

Covid-19, the first case of which was reported in Wuhan (China) in December 2019 was found to be a strain of coronaviruses like SARS and MERS reported earlier. These viruses are positive strain RNA viruses composed of both structural as well as non-structural proteins. The enzyme RdRp (RNA dependent RNA polymerase) stands responsible for catalyzing the replication of this virus within the host cell. A disruption in the core catalytic subunit composed of nsp12, nsp7, and nsp8 may inhibit the replication of the same. Different drugs targeting different sites on the virus have been developed. In this context, some of the natural products of the plant Centella asiatica was lead for further drug development against the target proteins of RdRp protein (PDB ID: 6NUR) through molecular docking. These compounds are 2,3-dihydroxyurs-12-en-28-oic acid, corosolic acid and pomolic acid which are triterpenoids and have highest binding affinity against RdRp protein thereby arresting the viral replication. Several previous studies showed triterpenoids as pertinent mediators implicated in the in vitro immune response.