Page 155 - EJMO-9-1
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Eurasian Journal of Medicine and
            Oncology
                                                                               Potential of flavonoids against glioblastoma


            in cancer progression were selected for analysis. These   default parameters were maintained for site constraints,
            proteins included UPAR (PDB ID: 2FD6), P38 (PDB ID:   rotatable  groups,  and  excluded  volumes,  ensuring  an
            3ZYA), NRF (PDB ID: 4XMB), ERK (PDB ID: 5NHJ),     optimized environment for ligand docking. 24
            mTOR (PDB ID: 5OQ4), STAT (PDB ID: 6NUQ), BCL-XL
            (PDB ID: 6RNU), MMP-9 (PDB ID: 4WZV), NRAS (PDB    2.4.6. Molecular docking
            ID: 6ZIR), and AKT1 (PDB ID: 3O96). These targets were   Molecular docking was conducted to explore the interaction
            chosen  based  on  specific  criteria:  they  originate  from   dynamics between the ligands and their respective protein
            Homo sapiens, possess a resolution of less than 3 Å, and   targets.  This  was  accomplished  using  the  Glide  module
            are devoid of mutations, except for NRAS (PDB ID: 6ZIR).   within the Maestro interface of Schrodinger 2020-3. Both
            The proteins were downloaded in PDB format, while the   Compounds 1 and 2, along with the CCLs, were subjected
            co-crystal ligands (CCLs) of each protein were saved in   to flexible docking simulations using the energy-minimized
            SDF format for subsequent docking analyses.        conformations derived from the earlier steps. The docking
                                                               mode was set to extra precision (XP), which is designed
            2.4.3. Preparation of ligands
                                                               to yield highly reliable binding affinity predictions. In
            The ligands, including Compounds 1 and 2, along with the   addition,  the  root  mean  square  deviation  (RMSD)  was
            CCLs, were subjected to optimization using the Ligprep tool   calculated for the input ligand geometries to validate the
            within Maestro, Schrodinger 2020-3 (version  12.5.139).   accuracy of the docking procedure.  Finally, the top-
                                                                                             23
            The aim was to achieve energy-minimized 3D structures   scoring ligands were visualized in the BIOVA Discovery
            with  accurate chiralities  at a pH  level of 7.0  ± 2 while   Studio Visualizer (version  21.1.0.20298), enabling a
            maintaining default settings for consistency. To enhance   detailed examination of the molecular interactions within
            the  accuracy  of  the  molecular  modeling,  the  OPLS3e   the active site of each target protein and providing valuable
            (Optimized Potentials for Liquid Simulations) force field   insights into their binding mechanisms.
            was  employed  during  the ligand minimization  process,
            which significantly improved the conformational stability   2.4.7. Prediction of absorption, distribution,
            of the compounds. 22                               metabolism, and excretion properties
            2.4.4. Preparation of proteins                     Understanding the absorption, distribution, metabolism,
                                                               and excretion (ADME) characteristics of phytochemicals
            Protein preparation was conducted using the Protein   is a crucial step in the drug discovery process. These
            Preparation Wizard tool available in the Maestro interface   pharmacokinetic properties play a vital role in
            of Schrodinger 2020-3 (version 12.5.139). Initially, each   determining the effectiveness of a potential therapeutic
            protein was individually imported into the workspace   agent’s effectiveness, as many drug candidates fail due
            and underwent preprocessing, which involved filling in   to unfavorable ADME profiles, leading to issues in drug
            missing loops and chains using the Prime job module.   development and clinical outcomes.  To mitigate these
                                                                                             25
            Subsequent steps included the deletion of extra side   risks and ensure the viability of the compounds, we
            chains and the assignment of zero-order bonds to metal   conducted a comprehensive ADME analysis following the
            atoms. Optimization was carried out at a specific pH of   molecular docking studies.
            7.0  ±  2,  following the PROPKA predictions,  to ensure
            optimal ionization states. In addition, water molecules   For this purpose, we utilized SwissADME, an advanced
            located beyond 3 Å from the binding site were removed   tool specifically designed to assess the pharmacokinetic
            to refine the protein’s active site environment. The final   attributes  of  chemical  compounds.  The  2D molecular
            step involved energy minimization using the OPLS3e   structures  of  the  phytochemicals  were  transformed
            force field to ensure the protein’s stability for docking   into Simplified Molecular Input Line Entry System
            procedures. 23                                     (SMILES) strings, providing a simplified yet highly
                                                               precise representation of their chemical makeup. This
            2.4.5. Receptor grid generation                    conversion enabled a more rigorous and detailed analysis
            Receptor grid generation was a critical step in the   of the compounds’ potential drug-like properties. During
            docking process, executed using Maestro’s Receptor Grid   this  evaluation,  each  phytochemical  was  systematically
            Generation tool. The active binding site of each protein-  screened against Lipinski’s Rule of Five (LRF), a widely
            ligand complex was pinpointed, and the grid was centered   recognized standard that predicts the oral bioavailability of
            on the centroid of the CCL for each target protein. To refine   chemical entities based on key molecular parameters, such
            this grid, a scaling factor of 1.0 was applied to the van der   as molecular weight, lipophilicity, hydrogen bond donors,
            Waals radii alongside a partial charge cutoff of 0.25. The   and acceptors. 26


            Volume 9 Issue 1 (2025)                        147                              doi: 10.36922/ejmo.5768
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