Comprehensive Computational and In Vivo Approaches to Assess the Analgesic Activity of the Selected Flavonoids from the <i>Maclura</i> Plant Against the Mu‐Opioid Receptor

Abstract The Maclura plant and its active constituents have been reported for various biological activities including inflammation, cancer, and neurological disorders. The various flavonoids that are reported from the Maclura plant include Morin, Rutin, Quercetin, and Kaempferol. These constituents were evaluated in the present study against the central pain receptor, i.e., Mu‐opioid receptor, whose activation is associated with a significant reduction in pain responses. The computational studies showed that Morin and Rutin bind with the Mu receptor vividly and the highest binding score was noted with the Mu receptor. The docking studies of the top two compounds (Morin and Rutin) were subjected to assess the dynamic behavior of ligand‐receptor complexes using molecular dynamic simulation. The simulation studies showed marked stability of both Morin and Rutin with Mu receptor and no significant changes were noticed in the protein following binding with the receptor. The simulation studies were commenced by the free binding energies calculation using MM‐PBSA/GBSA analysis. The results of the simulation were validated by the free energy calculations and revealed favorable binding affinities of the Morin and Rutin with the Mu receptor. Furthermore, the PCA analysis and free energy landscape analysis further validated the results and exhibited dynamic stability of the complexes during the transition of the conformation. Additionally, the in vivo analgesic studies were performed to validate the result of the computational studies. The results of in vivo studies using acetic acid and Carrageenan model showed that the intervention of the Morin and Rutin markedly attenuated the pain responses.