Implementation of In-Silico Drug Design to Find Natural Product-Based SARS-CoV 2 Spike Protein Inhibitor

COVID-19 has been a threat to the whole world due to its massive amount of infectivity. The causative SARS- CoV virus has an extremely small biological footprint. However, it has the ability to bind with the host cell, which, in this case, the human upper respiratory tract, with the intervention of a minimal amount of enzymes and energy. For this anchoring, this virus uses a specially designed protein known as the spike protein or S-protein which also gives the virus its unique shape. Unfortunately, even after the discovery of the vaccine, the number of people getting it is still significant. This is due to the ability of the virus to prevaricate immunity through constant mutation. Therefore, the search for an antiviral drug is still necessary. While there are only a few identified targets of anti-SARS-CoV drug designing, the S-protein can be unique for two reasons; first, it can be both virostatic and can be used as a postexposure prophylaxis measure. Here, in this book chapter, we look into several drugdesigning techniques that can be utilized for designing a molecule that can prevent the first stage of infection, and that is to attach with the ACE receptor of the host cell using the S-protein. Both ligand-based and structure-based designs have been taken into consideration, with a special focus on lead molecules obtained from natural products.