Novel chalcone derivatives of ursolic acid as acetylcholinesterase inhibitors: Synthesis, characterization, biological activity, ADME prediction, molecular docking and molecular dynamics studies

Acetylcholinesterase (AChE) is a critical target in the prevention of Alzheimer's Disease (AD) progression. With the goal of developing potential acetylcholinesterase inhibitors, a new series chalcone derivatives of ursolic acid (4-11) were synthesized and characterized by means of their NMR, FTIR and HRMS spectral data. hAChE inhibition abilities of all compounds were tested in vitro. Compounds 10, 8 and 7 showed high hAChE inhibitory potential with the IC50 values of 1.82, 4.65 and 5.36 mu M respectively. When compared to the standard inhibitor (Galantamine, IC50= 1.96 mu M), compound 10 was the most potent derivative. After performing kinetic studies, KM constant and Vmax value of hAChE were determined as 0.059 mM and 0.052 EU/ml respectively. Inhibition type of compound 10 was found as competitive and Ki constant was calculated as 1.31 +/- 0.18 mu M. The inhibition mechanism of compounds was predicted by molecular docking, MM/GBSA analysis, molecular dynamics simulation and ADME studies. Molecular docking studies showed that compounds 10, 8, and 7 have highest binding scores (-9.235,-8.827,-8.645 kcal/mol, respectively), while the standard inhibitor galantamine exhibited binding score of-5.106 kcal/mol. According to the MM/GBSA analysis, compounds 10 and 7 displayed binding free energies of-46.19 and-49.19 kcal/mol, respectively, which were higher than the standard's binding free energy of-41.82 kcal/mol. Molecular dynamic simulations were confirmed successful placement of the compounds 10, 8 and 7 in the active site of AChE. The in silico ADME predictions indicated that compound 10 has acceptable potency as a drug in treatment of AD.