Alzheimer's disease (AD) is a progressive and incurable neurodegenerative disorder, with a dramatic socioeconomic impact. The progress of AD is characterized by a severe loss in memory and cognition, leading to behavioral changing, depression and death. During the last decades, only a few anticholinergic drugs were launched in the market, mainly acetylcholinesterase inhibitors (AChEIs), with indications for the treatment of initial and moderate stages of AD. The search for new AChEIs, capable to overcome the limitations observed for rivastigmine and tacrine, led Sugimoto and co-workers to the discovery of donepezil. Besides its high potency, donepezil also exhibited high selectivity for AChE and a very low toxicity. In this review, we discuss the main structural and pharmacological attributes that have made donepezil the first choice medicine for AD, and a versatile structural model for the design of novel AChEIs, in spite of multipotent and multitarget-directed ligands. Many recent data from literature transdue great efforts worldwide to produce modifications in the donepezil structure that could result in new bioactive chemical entities with innovative structural pattern. Furthermore, multi-potent ligands have also been designed by molecular hybridization, affording rivastigmine-, tacrine- and huperzine-donepezil potent and selective AChEIs. In a more recent strategy, structural features of donepezil have been used as a model to design multitarget-directed ligands, aiming at the discovery of new effective drug candidates that could exhibit concomitant pharmacological activities as dual or multi- enzymatic inhibitors as genuine innovative therapeutic alternatives for the treatment of AD.

Alzhei er's Disease: Characterizatio , Evolution and Implications of the Neuroinflammatory ProcessAbstract: álzhei e 'sàDiseaseà áD àisàaà eu odege e ativeàdisease characterized by a progressive memory loss and severe cognition decline, associated to degradation of cholinergic neurons in many areas of central nervous system (CNS), with a dramatic reduction in neurotransmitters, specially acetylcholine. The illness progression is also accompanied by behavior changes, leading to individual incapacity and depression, and evolving to dementia and death. AD is related to cerebral aging and located loss of neurons, mainly at hippocampus and basal pro-encephalic tissue. Pathohystologically, AD is characterized by extracellular deposits of senile plaques formed by insoluble fragments of amyloid protein precursor (A) and intracellular neurofibrillary tangles in the brain, constituted by fragments of hyperphosphorylated TAU protein, with a massive loss in neurons. Despite typical behavior aspects of AD installation, recent studies, especially from the last decade, have evidenced the occurrence of a complex inflammatory process in the neuronal tissue. The relevancy of neuroinflammation in the installation, progression and severity of AD, as well as the mechanisms of immune system activation and key cells in the initial shot of inflammatory cascade in CNS, as microglia and astrocytes, have been demonstrated by important reviews in the literature. Activation of microglia can lead to recruitment of astrocytes that increase the inflammatory response to the extracellular A deposits. This neuroinflammatory component of AD is additionally characterized by a local acute phase response mediated by cytokines, complement cascade activation and induction of an enzymatic inflammatory system, as induced NO synthase (iNOS) and generation of cyclooxygenase 2 (COX-2). Then, astrocytes participate of the degradation and remotion of A, acting as a protective barrier between A deposits and neurons. The multifactorial character of the inflammatory response is characterized by the occurrence of a wide diversity of pro-and anti-inflammatory mediators, some of them being responsible for promotion of neurodegenerative mechanisms, while others could limit the advance of inflammation or exert benefit neurotrophic effects. Therefore, it includes not only a single mediator, but a set of inflammatory agents that would determine the prevalence of benefic or deletery effects during AD progression.Keywords: álzhei e 'sàDisease;àNeu odege e atio ;àNeu oi fla atio . 287Rev. Virtual Quim. |Vol 3| |No. 4| |286-306| ResumoA Doença de Alzheimer (DA) é uma doença neurodegenerativa, caracterizada pela diminuição progressiva da memória e declínio severo da cognição, associados com a degradação de neurônios colinérgicos em muitas áreas do Sistema Nervoso Central (SNC), acompanhada de dramática redução de neurotransmissores, entre os quais a acetilcolina (ACh) é o mais importante. A evolução da doença é acompanhada de alterações comportamentais, que evoluem à in...

In the title compound, C13H19NO2, the piperidine ring has a chair conformation with the exocyclic N—C bond in an equatorial position. In the crystal, mol­ecules are linked head-to-tail by phenol O—H⋯O hydrogen bonds to hy­droxy­methyl­ene O-atom acceptors, forming chains which extend along [100]. These chains form two-dimensional networks lying parallel to (101) through cyclic hydrogen-bonding associations [graph set R 4 4(30)], involving hy­droxy O—H donors and piperidine N-atom acceptors.