ACE2 and COVID-19: The 3D protein structures were retrieved from the RCSB Protein Data Bank [42] for established and validated targets such as main protease (Mpro) (PDB ID 7K40), spike glycoprotein—ACE2 receptor binding domain (spike ACE2 RBD) (PDB ID 6M0J), RNA-dependent RNA polymerase (RdRp) (PDB ID 7BV2) for COVID-19, enoyl acyl carrier protein reductase (InhA) (PDB ID 4TZK), decaprenyl-phosphoryl-ribose 2′-epimerase (DprE1) (PDB ID 4P8N) for tuberculosis, epidermal growth factor receptor (EGFR) (PDB ID 3POZ), phosphoinositide 3-kinase gamma (PI3K) (PDB ID 3L54) and caspase-3 (PDB ID 3DEI) for cancer.