Propargylamine-derived multi-target directed ligands for Alzheimer's disease therapy.

Current options for the treatment of Alzheimers disease have been restricted to prescription of acetylcholinesterase inhibitors or N-methyl-d-aspartate receptor antagonist, memantine. Propargylamine-derived multi-target directed ligands, such as ladostigil, M30, ASS234 and contilisant, involve different pathways. Apart from acting as inhibitors of both cholinesterases and monoamine oxidases, they show improvement of cognitive impairment, antioxidant activities, enhancement of iron-chelating activities, protect against tau hyperphosphorylation, block metal-associated oxidative stress, regulate APP and Aß expression processing by the non-amyloidogenic α-secretase pathway, suppress mitochondrial permeability transition pore opening, and coordinate protein kinase C signaling and Bcl-2 family proteins. Other hybrid propargylamine derivatives are also reported.

Exploring the structural basis of the selective inhibition of monoamine oxidase A by dicarbonitrile aminoheterocycles: role of Asn181 and Ile335 validated by spectroscopic and computational studies.

Since cyanide potentiates the inhibitory activity of several monoamine oxidase (MAO) inhibitors, a series of carbonitrile-containing aminoheterocycles was examined to explore the role of nitriles in determining the inhibitory activity against MAO. Dicarbonitrile aminofurans were found to be potent, selective inhibitors against MAO A. The origin of the MAO A selectivity was identified by combining spectroscopic and computational methods. Spectroscopic changes induced in MAO A by mono- and dicarbonitrile inhibitors were different, providing experimental evidence for distinct binding modes to the enzyme. Similar differences were also found between the binding of dicarbonitrile compounds to MAO A and to MAO B. Stabilization of the flavin anionic semiquinone by monocarbonitrile compounds, but destabilization by dicarbonitriles, provided further support to the distinct binding modes of these compounds and their interaction with the flavin ring. Molecular modeling studies supported the role played by the nitrile and amino groups in anchoring the inhibitor to the binding cavity. In particular, the results highlight the role of Asn181 and Ile335 in assisting the interaction of the nitrile-containing aminofuran ring. The network of interactions afforded by the specific attachment of these functional groups provides useful guidelines for the design of selective, reversible MAO A inhibitors.

Predicting targets of compounds against neurological diseases using cheminformatic methodology.

Recently developed multi-targeted ligands are novel drug candidates able to interact with monoamine oxidase A and B; acetylcholinesterase and butyrylcholinesterase; or with histamine N-methyltransferase and histamine H3-receptor (H3R). These proteins are drug targets in the treatment of depression, Alzheimer's disease, obsessive disorders, and Parkinson's disease. A probabilistic method, the Parzen-Rosenblatt window approach, was used to build a "predictor" model using data collected from the ChEMBL database. The model can be used to predict both the primary pharmaceutical target and off-targets of a compound based on its structure. Molecular structures were represented based on the circular fingerprint methodology. The same approach was used to build a "predictor" model from the DrugBank dataset to determine the main pharmacological groups of the compound. The study of off-target interactions is now recognised as crucial to the understanding of both drug action and toxicology. Primary pharmaceutical targets and off-targets for the novel multi-target ligands were examined by use of the developed cheminformatic method. Several multi-target ligands were selected for further study, as compounds with possible additional beneficial pharmacological activities. The cheminformatic targets identifications were in agreement with four 3D-QSAR (H3R/D1R/D2R/5-HT2aR) models and by in vitro assays for serotonin 5-HT1a and 5-HT2a receptor binding of the most promising ligand (71/MBA-VEG8).

Multicomponent Reactions for Multitargeted Compounds for Alzheimer`s Disease.

Alzheimer's Disease (AD) is a multifactorial and fatal neurodegenerative disorder affecting around 35 million people worldwide, which is characterized by decline of cholinergic function, deregulation of amyloid beta (Aß) oligomers formation and Aß fibril deposition. Multi-Target- Directed Ligands (MTDLs) have emerged as an original strategy for developing new therapeutic agents on AD. Multicomponent Reactions (MCRs) are a useful alternative to sequential multistep syntheses, allowing scaffold diversity and a rapid and easy access to biologically relevant compounds. The biological diversity of MCRs is very rich providing great possibilities for researchers interested in bioactive small molecular weight compounds. Since the MTDL strategy has been used to develop compounds endowed with the capacity to interact with different targets, versatile compound libraries may be obtained by MCRs according to the well established features of each target. Thus, either MTDLs or monotarget compounds have been developed by MCRs to address different factors implicated in AD. This work focuses on antioxidants, calcium channel modulators, both AChE and BuChE inhibitors, BACE1 inhibitors, and modulators of the nuclear factor (erythroid-derived 2)-like 2. First, we discuss the Biginelli reaction and its use for developing new interesting compounds for AD, followed by the contribution of Ugi reaction and, finally, the interest of other MCRs in the same topic.

Galanthamine, a natural product for the treatment of Alzheimer's disease.

(-)-Galanthamine is a selective, reversible competitive acetylcholinesterase inhibitor that has been recently approved for the symptomatic treatment of Alzheimer's disease. Galanthamine is a natural product belonging to the Amaryllidaceae family of alkaloids. The pharmacological history of galanthamine shows that the bioactive compound was discovered accidentally in the early 1950s, and the plant extracts were initially used to treat nerve pain and poliomyelitis. In addition, galanthamine had since been tested for use in anesthesiology, from facial nerve paralysis to schizophrenia. Galanthamine is a long-acting, selective, reversible and competitive AChE inhibitor that has recently been tested in AD patients and found to be readily absorbed, to be a performance enhancer on memory tests in some patients, and to be well tolerated, although some cholinergic side effects were observed. A number of total synthetic approaches have been reported, and a method for the industrial scale-up preparation of galanthamine is now being developed and patented. A variety of galanthamine derivatives have also been synthesized aiming to develop an agent free from cholinergic adverse effects. Galanthamine is a natural product that complements other synthetic drugs for the management of AD. In this account we will review the recent patent literature showing the most important advance on the chemistry of galanthamine.