Heterocyclic Secretase Inhibitors for the Treatment of Alzheimer’s Disease: An Overview

Alzheimer's disease (AD) is the most common neurodegenerative disorder and demands approaches for prevention and delayed onset. The development of therapeutics for AD is based on the amyloid cascade hypothesis (vaccines, β- and γ-Secretase inhibitors), or targeting tau and neurofibrillary tangle formation, neuroinflammation, etc. Cholinesterase, BACE-1, amyloid-β 1-42, γ and β-Secretase, and Phosphodiesterase type IV (PDE4) inhibitors are the reported treatment options. Among these, the γ- and β-Secretase inhibitors can be clustered in several heterocyclic classes (imidazoles, thiazoles, indoles, benzaldehydes, pyrimidine, etc), with subsequent description of the structure-activity relationships, and extended to the pharmacological profile in order to evaluate their drug-likeness, with special attention to toxicity and bioavailability. This article discusses the approaches proposed by several research groups working on the synthesis of enzyme inhibitors, based on modelling studies and the way these findings were used to obtain new drugs for the treatment of AD.