Figure 1.

Proposed mechanisms to block the entry of SARS-CoV-2 into host cells.

Notes: The mechanism behind SARS-CoV-2 entry into the host cell is schematically represented. Three proposed models are depicted where COVID-19 infection can be abrogated by blocking the interaction of RBD of spike (S) protein and ACE2. In one of the approaches, ACE2-RBD interaction can be destabilized by small molecules. In the second approach, ACE2 can be blocked with RBD mimetics or single-chain antibody fragment (scFv) against ACE2. In the third approach, RBD of SARS-CoV-2 S-protein can be blocked using the ACE-2 extracellular domain. An Fc domain fused to ACE-2 would facilitate prolonged circulation of the biologic (ACE2-Fc). The observations made in this study support the strategy to block or weaken the interaction between RBD and ACE2 by using phytocompounds of natural origin.