Anticholinesterase Agents For Alzheimer's Disease Treatment: An Updated Overview

Abstract

Background: Alzheimer's disease (AD) is a progressive neurodegenerative disease that compromises the cognitive system and causes dementia. In general, AD affects people over 65 years old, which implies a social impact if we consider future projections due to the increase in life expectancy. The drugs currently marketed only slow the progression of the disease. In this sense, the search for new drugs is a relevant topic in medicinal chemistry. The therapeutic strategy adopted herein is the cholinergic hypothesis, for which acetylcholinesterase enzyme (AChE) inhibitors constitute the main treatment for the disease. Objective: This review compiles research in synthetic and natural compounds with AChE inhibitory function. Methods: Data were collected based on investigations of AChE inhibitors in the last 5 years of the 2010 decade. Synthetic and natural compounds were investigated, for which Ligand Based Drug Design (LBDD) and Structure Based Drug Design (SBDD) strategies were performed to better understand the structure-activity relationship of promising therapeutic agents. Results: Prediction of physicochemical and pharmacokinetic properties used to calculate the bioavailability radar, lipophilicity, drug-likeness, and pharmacokinetics parameters (SwissADME) indicated that most active compounds are associated with the following characteristics: molecular weight above 377 g/mol; molar refractivity over 114; fraction Csp3 below 0.39 and TPSA above 43 Å2. The most active compounds had a lipophilicity parameter in the range between 2.5 and 4.52, a predominating lipophilic character. Atoms and bonds/interactions relevant for drug development were also investigated and the data pointed out the following tendencies: number of heavy atoms between 16 and 41; number of aromatic heavy atoms between 6 and 22; number of rotatable bonds between 1 and 14; number of H-bond acceptors between 1 and 11; number of H-bond donors below 7. Molecular docking studies indicated that all compounds had higher Goldscores than the drugs used as a positive control, indicating a stronger interaction with the enzyme. Conclusion: the selected compounds represent a potential for new anticholinesterase drugs and may be good starting-point for the development of new candidates. Also, design rules can be extracted from our analysis.