Integrated Computational Evaluation of Natural Flavonoids as Potential GRK6 Inhibitors Using DFT, ADME, Docking, and Molecular Dynamics

ABSTRACT Flavonoids are natural polyphenolic compounds commonly known for a variety of biological activities, including enzyme inhibition and therapeutic effects. In this study, two flavonoids, toxifoline (NM1) and quercetin (NM2), are tested in the context of the inhibitory effect on G protein‐coupled receptor kinase 6 (GRK 6) using computational tools. The evaluation of ADME properties showed a satisfactory profile, with a favorable molecular mass, high GI absorption, zero Lipinski violations, and non‐P‐gp substrate status. Neither of the compounds can cross the blood–brain barrier, and NM1 does not inhibit potent CYP isoforms. The binding affinity of the compounds was found to be high with GRK6 protein, with a binding score of −9.042 and −9.614 kcal/mol for NM1 and NM2, respectively, demonstrating an interaction energy of −62.214 (NM1) and −57.907 kcal/mol (NM2). The results of the DFT calculations revealed that the HOMO‐LUMO energy gaps between NM1 and NM2 are almost similar, 3.603 and 3.537 eV, respectively, reflecting closed chemical reactivity. However, the chemical hardness (NM1 1.802, NM2 1.769) and softness (NM1 0.555, NM2 0.565) values reveal that NM2 is more reactive than NM1, which aligns with the docking values. A 50 ns molecular dynamics simulation was performed on Google Colab to measure the stability of NM1 in the binding pocket, which confirmed small RMSD (∼1.5–2.1 Å) values, low residue flexibility (< 2.5 Å in most regions), and stable interaction energies (−70 to −80 kcal/mol). The protein was maintained in a compact form (Rg ∼22 Å), where no significant conformational alterations took place, and stable interactions of NM1 with GRK6 were detected in a dynamic milieu. These findings indicate that NM1 and NM2 demonstrate favorable pharmacokinetic and electronic properties and possess potential inhibitory activity against GRK6, highlighting the need for further experimental validation.