Fig. 4.

a Ligand-based virtual screening: in the drug design and discovery process, ligand-based virtual screening is the most crucial step, which comprises different steps as shown in the figure. The initial step consists of database screening and the 3-D structural model's prediction through the active site for a special target and X-ray structure of complexes. Later on, pharmacophore modeling of selected compounds with selected features is performed, followed by pharmacophore and docking-based virtual screening of compounds. The screened compounds are subjected to different toxicity and physiochemical properties for further analysis. Finally, the lead compounds are subjected to in vitro and in vivo bioassays for validation. b structure-based virtual screening: it is another type of virtual screening applied in the drug discovery process, where target structure preparation and chemical compound library preparation are initial steps. Afterward, structural analysis and binding site prediction are done, followed by molecular docking of compounds with the selected target. Later on, molecular dynamics simulation studies are carried out to validate the screened compounds in silico, followed by experimental validation through bioassays