In silico molecular studies of natural compounds as possible anti-Alzheimer’s agents: ligand-based design

Abstract

Alzheimer disease (AD) is the most common form of dementia contributing to about 60–70% of cases. β-Site amyloid precursor protein cleaving enzyme-1 (BACE1) plays an important role in the onset of AD and has become one of the important drug targets for AD. This approach has led to the development of promising BACE1 inhibitors, many of which are going through different phases of clinical trials. Nonetheless, the high failure rate of lead drug candidates targeting BACE1 brought to the forefront the need for finding new drugs to uncover the mystery behind AD. This study focused on virtual screening of ~ 33,000 natural compounds to find potential BACE1 inhibitors. Multiple ligands pharmacophore model was generated using PHASE to screen retrieved compounds against a four-site (ADDR) hypothesis. Molecular docking was performed to predict the binding status of the natural compounds. Based on binding affinity, the top eight compounds were chosen for further analysis. The docked complexes were analyzed for binding free energy using PRIME MM/GBA calculation. The compounds were filtered for drug-likeness using ADME/TOX (absorption, distribution, metabolism, excretion and toxicity) prediction. AutoQSAR (automated quantitative structure activity relationship) was used to build a model for the prediction of compounds bioactivities. Despite retrieving a large number of compounds with favorable binding affinity, only a few were selected to be promising based on their ADME/TOX proprieties, binding free energy and predicted pIC50. This study identified four natural compounds (NPC469686, NPC262328, NPC29763 and NPC86744) as novel BACE1 inhibitors. The insights obtained from this study could be employed to produce next-generation drug for AD.