lipocrine and Alzheimer-Disease

Multitarget agents directed at selected molecular targets involved in the pathogenic cascade of Alzheimer's disease (AD) have been increasingly sought after in recent years, with the aim of achieving enhanced therapeutic efficiency with respect to single-target drugs and drug candidates. At the same time, much attention has been devoted to identifying high quality pharmacological tools to help explore the molecular mechanisms underlying AD without being exposed to physicochemical challenges. Herein, we discuss several examples of both types of compounds, taken from our own research and derived from the leads memoquin, lipocrine and bis(7)tacrine.

Topics: Acetylcholinesterase; Alkanes; Alzheimer Disease; Amyloid beta-Peptides; Animals; Enzyme Inhibitors; Ethylamines; Humans; Ligands; Tacrine; Thioctic Acid

The multifunctional nature of Alzheimer's disease (AD) provides the logical foundation for the development of an innovative drug design strategy centered on multi-target-directed-ligands (MTDLs). In recent years, the MTDL concept has been exploited to design different ligands hitting different biological targets. Our first rationally designed MTDL was the polyamine caproctamine (1), which provided a synergistic cholinergic action against AD by antagonizing muscarinic M(2) autoreceptors and inhibiting acetylcholinesterase (AChE). Lipocrine (7) represented the next step in our research. Due to its ability to inhibit AChE catalytic and non-catalytic functions together with oxidative stress, 7 emerged as an interesting pharmacological tool for investigating the neurodegenerative mechanism underlying AD. Memoquin (9) is a quinone-bearing polyamine endowed with a unique multifunctional profile. With its development, we arrived at the proof of concept of the MTDL drug discovery approach. Experiments in vitro and in vivo confirmed its multimodal mechanisms of action and its interaction with different end-points of the neurotoxic cascade leading to AD. More recently, the MTDL approach led to carbacrine (12). In addition to the multiple activities displayed by 7, 12 displayed an interesting modulation of NMDA receptor activity. The pivotal role played by this target in AD pathogenesis suggests that 12 may be a promising new chemical entity in the MTDL gold rush.

Topics: Alkanes; Alzheimer Disease; Animals; Carbazoles; Cholinesterase Inhibitors; Drug Delivery Systems; Drug Design; Ethylamines; Humans; Ligands; Tacrine; Thioctic Acid

Alzheimer's disease (AD) is a chronic neurodegenerative disorder and one of the earliest sings of AD is deficit in short term memory. Till now, the pathogenesis of AD has not been elucidated and the present one-drug-one-target paradigm of anti-AD-drug treatment seems not to be effective in clinic. Multi-target-directed anti-AD-drugs are those agents that may act on two or more targets implicated in AD. Based on the brief introduction of progress in the development of present anti-AD-drugs, the paper mainly focused on the advances in the field of multi-target-directed drug development both home and abroad, especially those studies on selective estrogen receptor modulators.

Topics: Alzheimer Disease; Animals; Drug Combinations; Drug Delivery Systems; Drugs, Chinese Herbal; Humans; Indans; Indoles; Selective Estrogen Receptor Modulators; Tacrine; Thioctic Acid

Topics: Acetylcholinesterase; Alzheimer Disease; Amyloid beta-Peptides; Antioxidants; Binding Sites; Calcium Channel Blockers; Chelating Agents; Cholinesterase Inhibitors; Humans; Huntington Disease; Ligands; Multiple Sclerosis; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurotransmitter Agents; Parkinson Disease; Plaque, Amyloid

Redox impairment is a prominent feature of Alzheimer's disease (AD). It has led to the "oxidative stress hypothesis", which proposes antioxidants as beneficial therapeutic tools in AD treatment. To date, a wide variety of antioxidants have been examined as neuroprotectants. However, success has been elusive in clinical trials. Several factors have contributed to this failure, including the complexity of the redox system in vivo. Potentially critical aspects include the fine-tuned equilibrium between antioxidant defenses and free radical production, the lack of specific antioxidant target(s), and the inherent difficulty in delivering antioxidants where they are needed. Herein, we highlight significant progress in the field. Future directions of antioxidant research are also presented.

Topics: Alzheimer Disease; Antioxidants; Humans; Oxidative Stress

Lipoic acid (LA) is a natural antioxidant. Its structure was previously combined with that of the acetylcholinesterase inhibitor tacrine to give lipocrine (1), a lead compound multitargeted against Alzheimer's disease (AD). Herein, we further explore LA as a privileged structure for developing multimodal compounds to investigate AD. First, we studied the effect of LA chirality by evaluating the cholinesterase profile of 1's enantiomers. Then, a new series of LA hybrids was designed and synthesized by combining racemic LA with motifs of other known anticholinesterase agents (rivastigmine and memoquin). This afforded 4, which represents a step forward in the search for balanced anticholinesterase and antioxidant capacities.

Topics: Acetylcholinesterase; Alzheimer Disease; Amyloid beta-Peptides; Antioxidants; Butyrylcholinesterase; Cell Line; Cholinesterase Inhibitors; Drug Discovery; Humans; Ligands; Peptide Fragments; Protein Multimerization; Protein Structure, Secondary; Thioctic Acid

Novel multitargeted antioxidants 3-6 were designed by combining the antioxidant features, namely, a benzoquinone fragment and a lipoyl function, of two multifunctional lead candidates. They were then evaluated to determine their profile against Alzheimer's disease. They showed antioxidant activity, improved following enzymatic reduction, in mitochondria and T67 cell line. They also displayed a balanced inhibitory profile against amyloid-beta aggregation and acetylcholinesterase, emerging as promising molecules for neuroprotectant lead discovery.

Topics: Alkanes; Alzheimer Disease; Amyloid beta-Peptides; Antioxidants; Cell Line, Tumor; Drug Design; Electron Transport; Ethylamines; Humans; Ligands; Protein Binding; Reactive Oxygen Species; Submitochondrial Particles; Thioctic Acid; Ubiquinone

The coupling of two different pharmacophores, each endowed with different biological properties, afforded the hybrid compound lipocrine (7), whose biological profile was markedly improved relative to those of prototypes tacrine and lipoic acid. Lipocrine is the first compound that inhibits the catalytic activity of AChE and AChE-induced amyloid-beta aggregation and protects against reactive oxygen species. Thus, it emerged as a valuable pharmacological tool to investigate Alzheimer's disease and as a promising lead compound for new anti-Alzheimer drugs.

Topics: Acetylcholinesterase; Alzheimer Disease; Amyloid beta-Peptides; Antioxidants; Butyrylcholinesterase; Cell Line; Cholinesterase Inhibitors; Humans; Neurons; Nootropic Agents; Reactive Oxygen Species; Structure-Activity Relationship; Tacrine; Thioctic Acid