Natural Products as Inhibitors of Coronavirus: An Update

In the past couple of decades, several corona virus infections have alarmed the world claiming deaths of huge population over the globe. Effective anti-viral agents have been researched for treatment of COVID-19 infection. Vaccination has come up as an ultimate prevention against SARS-CoV-2virus as many vaccines have been recommended by WHO to be used for prevention from COVID-19. Alternative treatment strategies to combat infection include drug repurposing as well as supportive therapies. Traditional medicines being used from ancient times for different disease conditions provide a wealth of chemical diversity. Different classes of natural products are being utilized to study their antiviral properties and contributed in past for different viral diseases. The aim of current review is to enumerate different secondary metabolites and their pharmacophoric features against corona viruses that can be further optimized to develop more potent inhibitors specific to SARS-CoV-2. This review systematically evaluates natural products and their synthetic/ semisynthetic analogs belonging to terpenoids, polyphenols, saponins, and alkaloids having antiviral activity against coronaviruses. The information obtained from scope of Indian medicinal plants is also discussed which may be evaluated in future against SARS-CoV-2. Thus, it is proposed that the natural products may be used to develop potential inhibitors using the knowledge gained from similar studies to prevent morbidity and mortalities due to SARS-CoV-2.