For rigid docking, advanced and widely used molecular grid-based docking program Autodock4.2 was executed for screening purposes. Prior to docking, protein structure was edited by adding hydrogen atoms and gasteiger charges in autodocktools to create PDBQT files. The energy minimized ligand structures were further edited in autodocktools (ADT) by defining root center, aromatic carbons, and torsions. In grid selections, the whole receptor structure was selected for autogrid calculation with 0.375 Å spacing surrounding all possible binding sites to perform blind docking. Finally, docking studies were carried out using the Lamarckian Genetic Algorithm (LGA) based on the grid maps of all atoms present in the receptors and ligands. Parameters were set to an initial population of 150 randomly placed individuals, a maximum of 2.5x10 7 energy evaluations, cluster tolerance of 2 Å (rms), output level 0 and maximum generations of 2.7x10 4 numbers for total 10 numbers of conformations. After each docking execution, the 10 docked conformers were clustered by autodocktools based on thermodynamic parameters. The compounds exhibiting negative binding energy ≥ 9.8 Kcal / mol were chosen from this screening.