Publications by authors named "Alexandre A De Castro"

Alzheimer's disease (AD) stands as the predominant contributor to dementia cases. The ongoing developments in our understanding of its pathogenesis have sparked the interest of researchers, driving them to explore innovative treatment approaches. Existing therapies incorporating cholinesterase inhibitors and/or NMDA antagonists have shown limited improvement in alleviating symptoms.

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  • Endocrine disruptors (EDCs) are complex contaminants that are tough to eliminate using traditional methods, leading researchers to explore adsorptive processes and eco-friendly enzyme-based approaches for their removal.
  • This paper discusses the occurrence, classification, and toxicity of EDCs, emphasizing the need for improved understanding of the adsorption mechanisms and interactions between enzymes and EDCs for effective mitigation.
  • It suggests that using computational tools like molecular docking and dynamics can enhance the development of new adsorbents and catalytic methods to better address the challenges posed by EDCs.
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Leishmaniasis, caused by protozoa of the genus , encompasses a group of neglected diseases with diverse clinical and epidemiological manifestations that can be fatal if not adequately and promptly managed/treated. The current chemotherapy options for this disease are expensive, require invasive administration and often lead to severe side effects. In this regard, our research group has previously reported the potent anti- activity of two coordination compounds (complexes) derived from 1,10-phenanthroline-5,6-dione (phendione): [Cu(phendione)].

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Organophosphorus compounds (OP) make up an important class of inhibitors, mostly employed as pesticides, even as chemical weapons. These toxic substances act through the inhibition of the acetylcholinesterase (AChE) enzyme, which results in elevated synaptic acetylcholine (ACh) levels, leading to serious adverse effects under the cholinergic syndrome. Many reactivators have been developed to combat the toxic effects of these AChE inhibitors.

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In this study, we systematically investigated the electronic structure, spectroscopic (nuclear magnetic resonance, infrared, Raman, electron ionization mass spectrometry, UV-Vis, circular dichroism, and emission) properties, and tautomerism of halogenated favipiravir compounds (fluorine, chlorine, and bromine) from a computational perspective. Additionally, the effects of hydration on the proton transfer mechanism of the tautomeric forms of the halogenated favipiravir compounds are discussed. Our results suggest that spectroscopic properties allow for the elucidation of such tautomeric forms.

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Understanding the effects of metabolism on the rational design of novel and more effective drugs is still a considerable challenge. To the best of our knowledge, there are no entirely computational strategies that make it possible to predict these effects. From this perspective, the development of such methodologies could contribute to significantly reduce the side effects of medicines, leading to the emergence of more effective and safer drugs.

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The development of bifunctional catalysts is of great interest in fine chemistry, since they are capable of promoting multicatalytic reactions involved in several important industrial processes. Iron oxyhydroxides have been identified as low-cost bifunctional catalysts. However, their applications are limited due to their weak acid character.

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A new and more aggressive strain of coronavirus, known as SARS-CoV-2, which is highly contagious, has rapidly spread across the planet within a short period of time. Due to its high transmission rate and the significant time-space between infection and manifestation of symptoms, the WHO recently declared this a pandemic. Because of the exponentially growing number of new cases of both infections and deaths, development of new therapeutic options to help fight this pandemic is urgently needed.

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Two new series of hitherto unknown dipeptides, containing an electrophilic nitrile or a non-electrophilic 2-amino-1,3,4-oxadiazole moiety were synthesized and evaluated in vitro as Cathepsin K (Cat K) inhibitors. From 14 compounds obtained, the oxadiazole derivatives 10a, 10b, 10e, and 10g acted as enzymatic competitive inhibitors with Ki values between 2.13 and 7.

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Organophosphorus (OP) compounds are used as both chemical weapons and pesticides. However, these agents are very dangerous and toxic to humans, animals, and the environment. Thus, investigations with reactivators have been deeply developed in order to design new antidotes with better efficiency, as well as a greater spectrum of action in the acetylcholinesterase (AChE) reactivation process.

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  • * The study found that HRP effectively removed these compounds, achieving higher efficiency for 4-bromophenol (93.87%) compared to 2,4-dichlorophenol (59.19%), with computational methods revealing 4-BP has a stronger binding affinity and lower activation energy in its reaction with HRP.
  • * Using techniques like density functional theory and molecular docking, researchers
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Acetylcholinesterase (AChE) is the key enzyme responsible for deactivating the ACh neurotransmitter. Irreversible or prolonged inhibition of AChE, therefore, elevates synaptic ACh leading to serious central and peripheral adverse effects which fall under the cholinergic syndrome spectra. To combat the toxic effects of some AChEI, such as organophosphorus (OP) nerve agents, many compounds with reactivator effects have been developed.

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Alzheimer's disease (AD) is a neurodegenerative disease that is usually accompanied by aging, increasingly being the most common cause of dementia in the elderly. This disorder is characterized by the accumulation of beta amyloid plaques (Aβ) resulting from impaired amyloid precursor protein (APP) metabolism, together with the formation of neurofibrillary tangles and tau protein hyperphosphorylation. The exacerbated production of reactive oxygen species (ROS) triggers the process called oxidative stress, which increases neuronal cell abnormalities, most often followed by apoptosis, leading to cognitive dysfunction and dementia.

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Elastase B (lasB) is a multifunctional metalloenzyme secreted by the gram-negative pathogen , and this enzyme orchestrates several physiopathological events during bacteria-host interplays. LasB is considered to be a potential target for the development of an innovative chemotherapeutic approach, especially against multidrug-resistant strains. Recently, our group showed that 1,10-phenanthroline-5,6-dione (phendione), [Ag(phendione)]ClO (Ag-phendione) and [Cu(phendione)](ClO).

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Studies with oximes have been extensively developed to design new reactivators with better efficiency, and greater spectrum of action. In this study, we aimed to analyze the influence of the Carbamoyl group position change in two isomeric oximes, K203 and K206, on the reactivation percentage of Mus musculus Acetylcholinesterase (MmAChE), inhibited by different nerve agents. Theoretical calculations were performed to assess the difference for the oxime activity with inhibited AChE-complexes and the factors that govern this difference.

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Organophosphorus compounds have been widely employed to the development of warfare nerve agents and pesticides, resulting in a huge number of people intoxicated annually, being a serious problem of public health. Efforts worldwide have been done in order to design new technologies that are capable of combating or even reversing the poisoning caused by these OP nerve agents. In this line, the bioremediation arises as a promising and efficient alternative for this purpose.

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The brain has a unique biological complexity and is responsible for important functions in the human body, such as the command of cognitive and motor functions. Disruptive disorders that affect this organ, e.g.

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Alzheimer's disease (AD) is the most common cause of dementia. Clinical progress in this pathogenesis field has drawn the attention of researchers, stimulating the investigation of novel treatment methods. Current therapies that deal with cholinesterase inhibitors and/or NMDA antagonists have shown a modest symptomatic potential, increasing the need for research into more efficient therapeutics.

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Pseudomonas aeruginosa is a non-fermentative, gram-negative bacterium that is one of the most common pathogens responsible for hospital-acquired infections worldwide. The management of the infections caused by P. aeruginosa represents a huge challenge in the healthcare settings due to the increased emergence of resistant isolates, some of them resistant to all the currently available antimicrobials, which results in elevated morbimortality rates.

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The serine/threonine protein phosphatase type 5 (PP5) is a promising target for designing new antitumor drugs. This enzyme is a member of the PPP phosphatases gene family, which catalyzes a dephosphorylation reaction: a regulatory process in the signal transduction pathway that controls various biological processes. The aim of this work is to study and compare the inhibition of PP5 by ten cantharidin-like inhibitors in order to bring about contributions relevant to the better comprehension of their inhibitory activity.

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Alzheimer's disease is known to be a chronic disease, with an estimated prevalence of about 10-30%, considering the population over 60 years of age. Most patients with this disorder (> 95%) present the sporadic form, being characterized by a late onset (80-90 years of age), and it is the consequence of the failure to clear the amyloid-β (Aβ) peptide from the interstices of the brain. Significant numbers of genetic risk factors for the sporadic disease have been researched.

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Organophosphorus compounds (OP) nerve agents are among the most toxic chemical substances known. Their toxicity is due to their ability to bind to acetylcholinesterase. Currently, some enzymes, such as phosphotriesterase, human serum paraoxonase 1 and diisopropyl fluorophosphatase, capable of degrading OP, have been characterized.

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The present work evaluates the action of nitroreductase enzyme immobilized on Tosylactivated magnetic particles (MP-Tosyl) on three disperse dyes which contain nitro and azo groups. The dyes included Disperse Red 73 (DR 73), Disperse Red 78 (DR 78), and Disperse Red 167 (DR 167). The use of a magnet enabled the rapid and easy removal of the immobilized enzyme after biotransformation; this facilitated the identification of the products generated using high-performance liquid chromatography with diode array detector (HPLC-DAD) and mass spectrometry (LC-MS/MS).

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Several rare or orphan diseases have been characterized that singly affect low numbers of people, but cumulatively reach ∼6%-10% of the population in Europe and in the United States. Human genetics has shown to be broadly effective when evaluating subjacent genetic defects such as orphan genetic diseases, but on the other hand, a modest progress has been achieved toward comprehending the molecular pathologies and designing new therapies. Chemical genetics, placed at the interface of chemistry and genetics, could be employed to understand the molecular mechanisms of subjacent illnesses and for the discovery of new remediation processes.

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Synthetic azo dyes have increasingly become a matter of great concern as a result of the genotoxic and mutagenic potential of the products derived from azo dye biotransformation. This work evaluates the manner in which reducing enzymes produced by Escherichia coli (E. coli) act on three disperse dyes bearing azo groups, namely Disperse Red 73 (DR 73), Disperse Red 78 (DR 78), and Disperse Red 167 (DR 167).

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