Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
1.
Arch Toxicol ; 97(1): 39-72, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36335468

RESUMO

Organophosphorus compounds (OP) are a constant problem, both in the military and in the civilian field, not only in the form of acute poisoning but also for their long-lasting consequences. No antidote has been found that satisfactorily protects against the toxic effects of organophosphates. Likewise, there is no universal cure to avert damage after poisoning. The key mechanism of organophosphate toxicity is the inhibition of acetylcholinesterase. The overstimulation of nicotinic or muscarinic receptors by accumulated acetylcholine on a synaptic cleft leads to activation of the glutamatergic system and the development of seizures. Further consequences include generation of reactive oxygen species (ROS), neuroinflammation, and the formation of various other neuropathologists. In this review, we present neuroprotection strategies which can slow down the secondary nerve cell damage and alleviate neurological and neuropsychiatric disturbance. In our opinion, there is no unequivocal approach to ensure neuroprotection, however, sooner the neurotoxicity pathway is targeted, the better the results which can be expected. It seems crucial to target the key propagation pathways, i.e., to block cholinergic and, foremostly, glutamatergic cascades. Currently, the privileged approach oriented to stimulating GABAAR by benzodiazepines is of limited efficacy, so that antagonizing the hyperactivity of the glutamatergic system could provide an even more efficacious approach for terminating OP-induced seizures and protecting the brain from permanent damage. Encouraging results have been reported for tezampanel, an antagonist of GluK1 kainate and AMPA receptors, especially in combination with caramiphen, an anticholinergic and anti-glutamatergic agent. On the other hand, targeting ROS by antioxidants cannot or already developed neuroinflammation does not seem to be very productive as other processes are also involved.


Assuntos
Síndromes Neurotóxicas , Intoxicação por Organofosfatos , Humanos , Acetilcolinesterase/metabolismo , Espécies Reativas de Oxigênio , Organofosfatos , Doenças Neuroinflamatórias , Síndromes Neurotóxicas/etiologia , Síndromes Neurotóxicas/prevenção & controle , Intoxicação por Organofosfatos/tratamento farmacológico , Intoxicação por Organofosfatos/prevenção & controle , Convulsões , Inibidores da Colinesterase/toxicidade
2.
Crit Rev Clin Lab Sci ; 59(8): 517-554, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35575431

RESUMO

Vitamin D has a well-known role in the calcium homeostasis associated with the maintenance of healthy bones. It increases the efficiency of the intestinal absorption of dietary calcium, reduces calcium losses in urine, and mobilizes calcium stored in the skeleton. However, vitamin D receptors are present ubiquitously in the human body and indeed, vitamin D has a plethora of non-calcemic functions. In contrast to most vitamins, sufficient vitamin D can be synthesized in human skin. However, its production can be markedly decreased due to factors such as clothing, sunscreens, intentional avoidance of the direct sunlight, or the high latitude of the residence. Indeed, more than one billion people worldwide are vitamin D deficient, and the deficiency is frequently undiagnosed. The chronic deficiency is not only associated with rickets/osteomalacia/osteoporosis but it is also linked to a higher risk of hypertension, type 1 diabetes, multiple sclerosis, or cancer. Supplementation of vitamin D may be hence beneficial, but the intake of vitamin D should be under the supervision of health professionals because overdosing leads to intoxication with severe health consequences. For monitoring vitamin D, several analytical methods are employed, and their advantages and disadvantages are discussed in detail in this review.


Assuntos
Raquitismo , Deficiência de Vitamina D , Humanos , Vitamina D/metabolismo , Vitamina D/uso terapêutico , Cálcio , Deficiência de Vitamina D/complicações , Deficiência de Vitamina D/tratamento farmacológico , Vitaminas , Raquitismo/complicações , Raquitismo/tratamento farmacológico , Cálcio da Dieta
3.
Opt Express ; 30(21): 37213-37223, 2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36258313

RESUMO

Squeezed states are an interesting class of quantum states that have numerous applications. This work presents the design, characterization, and operation of a bow-tie optical parametric amplifier (OPA) for squeezed vacuum generation. We report the high duty cycle operation and long-term stability of the system that makes it suitable for post-selection based continuous-variable quantum information protocols, cluster-state quantum computing, quantum metrology, and potentially gravitational wave detectors. Over a 50 hour continuous operation, the measured squeezing levels were greater than 10 dB with a duty cycle of 96.6%. Alternatively, in a different mode of operation, the squeezer can also operate 10 dB below the quantum noise limit over a 12 hour period with no relocks, with an average squeezing of 11.9 dB. We also measured a maximum squeezing level of 12.6 dB at 1550 nm. This represents one of the best reported squeezing results at 1550 nm to date for a bow-tie cavity. We discuss the design aspects of the experiment that contribute to the overall stability, reliability, and longevity of the OPA, along with the automated locking schemes and different modes of operation.

4.
Molecules ; 27(21)2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36364465

RESUMO

The synthesis of a tetrathiafulvalene (TTF) derivative, S-[4-({4-[(2,2'-bi-1,3-dithiol-4-ylmethoxy)methyl] phenyl}ethynyl)phenyl] ethanethioate, suitable for the modification of gold nanoparticles (AuNPs), is described in this article. The TTF ligand was self-assembled on the AuNP surface through ligand exchange, starting from dodecanethiol-stabilized AuNPs. The resulting modified AuNPs were characterized by TEM, UV-Vis spectroscopy, and electrochemistry. The most suitable electrochemical method was the phase-sensitive AC voltammetry at very low frequencies of the sine-wave perturbation. The results indicate a diminishing electronic communication between the two equivalent redox centers of TTF and also intermolecular donor-acceptor interactions manifested by an additional oxidation wave upon attachment of the ligand to AuNPs.


Assuntos
Ouro , Nanopartículas Metálicas , Ouro/química , Eletroquímica/métodos , Ligantes , Nanopartículas Metálicas/química
5.
Bioorg Med Chem Lett ; 51: 128374, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34555506

RESUMO

Alzheimers disease (AD) is the most common neurodegenerative disorder, characterized by neuronal loss and cognitive impairment. Currently, very few drugs are available for AD treatment, and a search for new therapeutics is urgently needed. Thus, in the current study, twenty-eight new derivatives of montanine-type Amaryllidaceae alkaloids were synthesized and evaluated for their ability to inhibit human recombinant acetylcholinesterase (hAChE) and butyrylcholinesterase (hBuChE). Three derivatives (1n, 1o, and 1p) with different substitution patterns demonstrated significant selective inhibitory potency for hAChE (IC50 < 5 µM), and one analog, 1v, showed selective hBuChE inhibition activity (IC50 = 1.73 ± 0.05 µM). The prediction of CNS availability, as disclosed by the BBB score, suggests that the active compounds in this survey should be able pass through the blood-brain barrier (BBB). Cytotoxicity screening and docking studies were carried out for the two most pronounced cholinesterase inhibitors, 1n and 1v.


Assuntos
Alcaloides/farmacologia , Doença de Alzheimer/tratamento farmacológico , Inibidores da Colinesterase/farmacologia , Isoquinolinas/farmacologia , Simulação de Acoplamento Molecular , Acetilcolinesterase/metabolismo , Alcaloides/síntese química , Alcaloides/química , Doença de Alzheimer/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Relação Dose-Resposta a Droga , Humanos , Isoquinolinas/síntese química , Isoquinolinas/química , Estrutura Molecular , Relação Estrutura-Atividade
6.
Bioorg Med Chem ; 41: 116209, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34015704

RESUMO

Hydrazide-hydrazones have been described as a scaffold with antimicrobial and cytotoxic activities as well as iodinated compounds. A resistance rate of bacterial and fungal pathogens has increased considerably. That is why we synthesized and screened twenty-two iodinated hydrazide-hydrazones 1 and 2, ten 1,2-diacylhydrazines 3 and their three reduced analogues 4 for their antibacterial, antifungal, and cytotoxic properties. Hydrazide-hydrazones were prepared by condensation of 4-substituted benzohydrazides with 2-/4-hydroxy-3,5-diiodobenzaldehydes, diacylhydrazines from identical benzohydrazides and 3,5-diiodosalicylic acid via its chloride. These compounds were investigated in vitro against eight bacterial and eight fungal strains. The derivatives were found potent antibacterial agents against Gram-positive cocci including methicillin-resistant Staphylococcus aureus with the lowest values of minimum inhibitory concentrations (MIC) of 7.81 µM. Four compounds inhibited also human pathogenic fungi (MIC of ≥1.95 µM). The derivatives had different degrees of cytotoxicity for HepG2 and HK-2 cell lines (IC50 values from 11.72 and 26.80 µM, respectively). Importantly, normal human cells exhibited lower sensitivity. The apoptotic effect was also investigated. In general, the presence of 3,5-diiodosalicylidene scaffold (compounds 1) is translated into enhanced both antimicrobial and cytotoxic properties whereas its 4-hydroxy isomers 2 share a low biological activity. N'-Benzoyl-2-hydroxy-3,5-diiodobenzohydrazides 3 have a non-homogeneous activity profile. Focusing on 4-substituted benzohydrazide part, the presence of an electron-withdrawing group (F, Cl, CF3, NO2) was found to be beneficial.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Hidrazinas/química , Hidrazonas/química , Antibacterianos/química , Antifúngicos/química , Antineoplásicos/química , Bactérias/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Descoberta de Drogas , Fungos/efeitos dos fármacos , Células Hep G2 , Humanos
7.
J Labelled Comp Radiopharm ; 64(7): 262-270, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-33818828

RESUMO

The key factors participating in angiogenesis include vascular endothelial growth factor (VEGF) and its receptors (VEGFRs), particularly VEGFR2. Angiogenesis suppression comprises the blocking of the VEGFR2 binding site by the monoclonal antibody ramucirumab (RAM). Our study focused on RAM radiolabelling with zirconium-89 along with subsequent in vitro and in vivo biological evaluation. RAM was conjugated with the bifunctional chelator p-SCN-Bn-deferoxamine (DFO) and subsequently radiolabelled with [89 Zr]Zr-oxalate. The binding affinity of [89 Zr]Zr-DFO-RAM to VEGFR2 was tested in vitro on prostate (PC-3) and ovary adenocarcinoma (SK-OV-3) cell lines. The positron emission tomography/computed tomography (PET/CT) imaging and ex vivo biodistribution experiments were performed in PC-3 and SK-OV-3 xenografted mice. The in vitro experiments revealed the preserved binding affinity of [89 Zr]Zr-DFO-RAM to VEGFR2. The obtained ex vivo biodistribution data showed the uptake in PC-3 and SK-OV-3 tumours at about 8.7 ± 0.2 and 12.1 ± 1.6%ID/g, respectively. The tumour-to-muscle ratio for 1, 3 and 6 days post injection was 3.9, 5.5 and 5.12 for PC-3 and 6.0, 8.0 and 8.82 for SK-OV-3 tumours, respectively. PET/CT images showed high radioactivity accumulation in the tumours starting already on the first day after tracer administration. The obtained results proved the potency of [89 Zr]Zr-DFO-RAM to target and image VEGFR2-positive tumours in vivo.


Assuntos
Radioisótopos , Zircônio
8.
Sensors (Basel) ; 21(12)2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34205763

RESUMO

Flocks of birds may cause major damage to fruit crops in the ripening phase. This problem is addressed by various methods for bird scaring; in many cases, however, the birds become accustomed to the distraction, and the applied scaring procedure loses its purpose. To help eliminate the difficulty, we present a system to detect flocks and to trigger an actuator that will scare the objects only when a flock passes through the monitored space. The actual detection is performed with artificial intelligence utilizing a convolutional neural network. Before teaching the network, we employed videocameras and a differential algorithm to detect all items moving in the vineyard. Such objects revealed in the images were labeled and then used in training, testing, and validating the network. The assessment of the detection algorithm required evaluating the parameters precision, recall, and F1 score. In terms of function, the algorithm is implemented in a module consisting of a microcomputer and a connected videocamera. When a flock is detected, the microcontroller will generate a signal to be wirelessly transmitted to the module, whose task is to trigger the scaring actuator.


Assuntos
Inteligência Artificial , Frutas , Animais , Aves , Redes Neurais de Computação
9.
Int J Mol Sci ; 22(15)2021 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-34361074

RESUMO

Alzheimer's disease (AD) is a multifactorial neurodegenerative condition of the central nervous system (CNS) that is currently treated by cholinesterase inhibitors and the N-methyl-d-aspartate receptor antagonist, memantine. Emerging evidence strongly supports the relevance of targeting butyrylcholinesterase (BuChE) in the more advanced stages of AD. Within this study, we have generated a pilot series of compounds (1-20) structurally inspired from belladine-type Amaryllidaceae alkaloids, namely carltonine A and B, and evaluated their acetylcholinesterase (AChE) and BuChE inhibition properties. Some of the compounds exhibited intriguing inhibition activity for human BuChE (hBuChE), with a preference for BuChE over AChE. Seven compounds were found to possess a hBuChE inhibition profile, with IC50 values below 1 µM. The most potent one, compound 6, showed nanomolar range activity with an IC50 value of 72 nM and an excellent selectivity pattern over AChE, reaching a selectivity index of almost 1400. Compound 6 was further studied by enzyme kinetics, along with in-silico techniques, to reveal the mode of inhibition. The prediction of CNS availability estimates that all the compounds in this survey can pass through the blood-brain barrier (BBB), as disclosed by the BBB score.


Assuntos
Acetilcolinesterase/química , Alcaloides de Amaryllidaceae/química , Butirilcolinesterase/química , Inibidores da Colinesterase/farmacologia , Simulação de Acoplamento Molecular , Neuroblastoma/tratamento farmacológico , Tiramina/análogos & derivados , Proliferação de Células , Inibidores da Colinesterase/química , Simulação por Computador , Humanos , Neuroblastoma/patologia , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Tiramina/química
10.
Molecules ; 25(7)2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32230728

RESUMO

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (Mtb), each year causing millions of deaths. In this article, we present the synthesis and biological evaluations of new potential antimycobacterial compounds containing a fragment of the first-line antitubercular drug pyrazinamide (PZA), coupled with methyl or ethyl esters of selected amino acids. The antimicrobial activity was evaluated on a variety of (myco)bacterial strains, including Mtb H37Ra, M. smegmatis, M. aurum, Staphylococcus aureus, Pseudomonas aeruginosa, and fungal strains, including Candida albicans and Aspergillus flavus. Emphasis was placed on the comparison of enantiomer activities. None of the synthesized compounds showed any significant activity against fungal strains, and their antibacterial activities were also low, the best minimum inhibitory concentration (MIC) value was 31.25 µM. However, several compounds presented high activity against Mtb. Overall, higher activity was seen in derivatives containing ʟ-amino acids. Similarly, the activity seems tied to the more lipophilic compounds. The most active derivative contained phenylglycine moiety (PC-ᴅ/ʟ-Pgl-Me, MIC < 1.95 µg/mL). All active compounds possessed low cytotoxicity and good selectivity towards Mtb. To the best of our knowledge, this is the first study comparing the activities of the ᴅ- and ʟ-amino acid derivatives of pyrazinamide as potential antimycobacterial compounds.


Assuntos
Aminoácidos/farmacologia , Antibacterianos/farmacologia , Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Pirazinamida/farmacologia , Tuberculose/tratamento farmacológico , Aminoácidos/química , Aspergillus flavus/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Células Hep G2 , Humanos , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Mycobacterium smegmatis/efeitos dos fármacos , Rotação Ocular , Pseudomonas aeruginosa/efeitos dos fármacos , Pirazinamida/química , Staphylococcus aureus/efeitos dos fármacos
11.
Vnitr Lek ; 66(6): 381-385, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33380144

RESUMO

Dieulafoy`s lesion is a rare condition characterized by bleeding into gastrointestinal tract from minimaly eroded submucous artery. Mostly is localized in stomach in elderly polymorbid men, but can occure in entire gastrointestinal tract, in both sexes, in every age. It should be thought off as one of possible causes of obscure bleeding. It is often massive, requiring fast diagnostics, treatment and multidisciplinary approach. The case report discusses patient with recurrent hemodynamicaly significant bleeding into jejunum. It pointed to combined diagnostic approach using both endoscopy and angiography. After failing endoscopically and angiografically due to hemodynamic instability, surgical intervention took place. Precise Dieulafoy`s lesion diagnosis has been determined eventually on histologic section. Diagnostic and therapeutic approach should be individual taking patient´s condition and capabilities of department into consideration. Surgical intervention remains golden standard when hemodynamic instability occures or when endoscopy and angiography fail.


Assuntos
Gastroenteropatias , Doenças Vasculares , Idoso , Angiografia , Feminino , Hemorragia Gastrointestinal/etiologia , Humanos , Jejuno/diagnóstico por imagem , Masculino
12.
Molecules ; 25(1)2019 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-31905775

RESUMO

We prepared a series of substituted N-(pyrazin-2-yl)benzenesulfonamides as an attempt to investigate the effect of different linkers connecting pyrazine to benzene cores on antimicrobial activity when compared to our previous compounds of amide or retro-amide linker type. Only two compounds, 4-amino-N-(pyrazin-2-yl)benzenesulfonamide (MIC = 6.25 µg/mL, 25 µM) and 4-amino-N-(6-chloropyrazin-2-yl)benzenesulfonamide (MIC = 6.25 µg/mL, 22 µM) exerted good antitubercular activity against M. tuberculosis H37Rv. However, they were excluded from the comparison as they-unlike the other compounds-possessed the pharmacophore for the inhibition of folate pathway, which was proven by docking studies. We performed target fishing, where we identified matrix metalloproteinase-8 as a promising target for our title compounds that is worth future exploration.


Assuntos
Anti-Infecciosos/síntese química , Anti-Infecciosos/farmacologia , Sulfonamidas/síntese química , Sulfonamidas/farmacologia , Anti-Infecciosos/química , Antituberculosos/síntese química , Antituberculosos/química , Antituberculosos/farmacologia , Fenômenos Químicos , Técnicas de Química Sintética , Testes de Sensibilidade Microbiana , Modelos Moleculares , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Relação Estrutura-Atividade , Sulfonamidas/química , Benzenossulfonamidas
13.
Phys Rev Lett ; 120(4): 040406, 2018 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-29437418

RESUMO

A Bell inequality is a fundamental test to rule out local hidden variable model descriptions of correlations between two physically separated systems. There have been a number of experiments in which a Bell inequality has been violated using discrete-variable systems. We demonstrate a violation of Bell's inequality using continuous variable quadrature measurements. By creating a four-mode entangled state with homodyne detection, we recorded a clear violation with a Bell value of B=2.31±0.02. This opens new possibilities for using continuous variable states for device independent quantum protocols.

14.
Molecules ; 23(9)2018 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-30231544

RESUMO

Three series of N-(pyrazin-2-yl)benzamides were designed as retro-amide analogues of previously published N-phenylpyrazine-2-carboxamides with in vitro antimycobacterial activity. The synthesized retro-amides were evaluated for in vitro growth inhibiting activity against Mycobacterium tuberculosis H37Rv (Mtb), three non-tuberculous mycobacterial strains (M. avium, M. kansasii, M. smegmatis) and selected bacterial and fungal strains of clinical importance. Regarding activity against Mtb, most N-pyrazinylbenzamides (retro-amides) possessed lower or no activity compared to the corresponding N-phenylpyrazine-2-carboxamides with the same substitution pattern. However, the active retro-amides tended to have lower HepG2 cytotoxicity and better selectivity. Derivatives with 5-chloro substitution on the pyrazine ring were generally more active compared to their 6-cloro positional isomers or non-chlorinated analogues. The best antimycobacterial activity against Mtb was found in N-(5-chloropyrazin-2-yl)benzamides with short alkyl (2h: R² = Me; 2i: R² = Et) in position 4 of the benzene ring (MIC = 6.25 and 3.13 µg/mL, respectively, with SI > 10). N-(5-Chloropyrazin-2-ylbenzamides with hydroxy substitution (2b: R² = 2-OH; 2d: R² = 4-OH) on the benzene ring or their acetylated synthetic precursors possessed the broadest spectrum of activity, being active in all three groups of mycobacterial, bacterial and fungal strains. The substantial differences in in silico calculated properties (hydrogen-bond pattern analysis, molecular electrostatic potential, HOMO and LUMO) can justify the differences in biological activities between N-pyrazinylbenzamides and N-phenylpyrazine-2-carboxamides.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Benzamidas/química , Benzamidas/farmacologia , Técnicas de Química Sintética , Desenho de Fármacos , Antibacterianos/síntese química , Benzamidas/síntese química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Relação Estrutura-Atividade
15.
J Labelled Comp Radiopharm ; 60(1): 80-86, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27966236

RESUMO

Radioimmunoassay belongs to the analytical method enabling highly specific and sensitive quantification of molecules. The verification of the real-time radioimmunoassay technology usefulness for ligand-quality characteristics evaluation such as concentration, influence of radiolabeling on binding affinity and stability was estimated. The anti-epidermal growth factor receptor antibody 131 I-cetuximab was employed as the ligand antibody. The concentration of 131 I-cetuximab was derived from the shape of binding curves coming from the ligand-receptor interaction. The binding curves also allowed the estimation of 131 I-cetuximab binding affinity for different radiolabeling procedures (incubation times 1, 5, and 10 minutes) in stability testing up to 96 hours at 4°C. The stability testing also included comparative analysis by size exclusion high-performance liquid chromatography. The assessment of cetuximab concentrations using real-time method showed acceptable accordance between real and calculated values. The real-time method revealed that 1-minute radiolabeling proved to be the optimal incubation time for direct radioiodination of cetuximab. Stability testing showed the significant change in radioligand affinity by one order at the longest incubation times (72 and 96 hours). Characterization of stability and binding behavior of radiolabeled monoclonal antibodies by the verified real-time method before use in other assays may be employed to eliminate variability and suboptimal antibody performance.


Assuntos
Antineoplásicos Imunológicos/química , Cetuximab/química , Radioisótopos do Iodo/química , Ensaio Radioligante/métodos , Compostos Radiofarmacêuticos/química , Antineoplásicos Imunológicos/farmacologia , Linhagem Celular Tumoral , Cetuximab/farmacologia , Humanos , Radioisótopos do Iodo/farmacologia , Ligantes , Radioimunoensaio/métodos , Radioimunoensaio/normas , Ensaio Radioligante/normas , Compostos Radiofarmacêuticos/farmacologia
16.
Molecules ; 22(9)2017 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-28925956

RESUMO

The resistance among microbes has brought an urgent need for new drugs. Thus, we synthesized a series of Schiff bases derived from the sulfa drug sulfadiazine and various salicylaldehydes. The resulting 4-[(2-hydroxybenzylidene)amino]-N-(pyrimidin-2-yl)benzene-sulfonamides were characterized and evaluated against Gram-positive and Gram-negative bacteria, yeasts, moulds, Mycobacterium tuberculosis, nontuberculous mycobacteria (M. kansasii, M. avium) and their cytotoxicity was determined. Among bacteria, the genus Staphylococcus, including methicillin-resistant S. aureus, showed the highest susceptibility, with minimum inhibitory concentration values from 7.81 µM. The growth of Candida sp. and Trichophyton interdigitale was inhibited at concentrations starting from 1.95 µM. 4-[(2,5-Dihydroxybenzylidene)amino]-N-(pyrimidin-2-yl)-benzenesulfonamide was identified as the most selective Schiff base for these strains with no apparent cytotoxicity and a selectivity index higher than 16. With respect to M. tuberculosis and M. kansasii that were inhibited within the range of 8 to 250 µM, unsubstituted 4-[(2-hydroxy-benzylidene)amino]-N-(pyrimidin-2-yl)benzenesulfonamide meets the selectivity requirement. In general, dihalogenation of the salicylic moiety improved the antibacterial and antifungal activity but also increased the cytotoxicity, especially with an increasing atomic mass. Some derivatives offer more advantageous properties than the parent sulfadiazine, thus constituting promising hits for further antimicrobial drug development.


Assuntos
Aldeídos/síntese química , Anti-Infecciosos/síntese química , Pirimidinas/síntese química , Bases de Schiff/síntese química , Sulfadiazina/análogos & derivados , Sulfadiazina/síntese química , Aldeídos/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células Hep G2 , Humanos , Testes de Sensibilidade Microbiana , Pirimidinas/farmacologia , Bases de Schiff/farmacologia , Relação Estrutura-Atividade , Sulfadiazina/farmacologia
17.
Molecules ; 22(10)2017 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-29065539

RESUMO

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) has become a frequently deadly infection due to increasing antimicrobial resistance. This serious issue has driven efforts worldwide to discover new drugs effective against Mtb. One research area is the synthesis and evaluation of pyrazinamide derivatives as potential anti-TB drugs. In this paper we report the synthesis and biological evaluations of a series of ureidopyrazines. Compounds were synthesized by reacting alkyl/aryl isocyanates with aminopyrazine or with propyl 5-aminopyrazine-2-carboxylate. Reactions were performed in pressurized vials using a CEM Discover microwave reactor with a focused field. Purity and chemical structures of products were assessed, and the final compounds were tested in vitro for their antimycobacterial, antibacterial, and antifungal activities. Propyl 5-(3-phenylureido)pyrazine-2-carboxylate (compound 4, MICMtb = 1.56 µg/mL, 5.19 µM) and propyl 5-(3-(4-methoxyphenyl)ureido)pyrazine-2-carboxylate (compound 6, MICMtb = 6.25 µg/mL, 18.91 µM) had high antimycobacterial activity against Mtb H37Rv with no in vitro cytotoxicity on HepG2 cell line. Therefore 4 and 6 are suitable for further structural modifications that might improve their biological activity and physicochemical properties. Based on the structural similarity to 1-(2-chloropyridin-4-yl)-3-phenylurea, a known plant growth regulator, two selected compounds were evaluated for similar activity as abiotic elicitors.


Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Pirazinas/farmacologia , Antituberculosos/síntese química , Antituberculosos/química , Proliferação de Células/efeitos dos fármacos , Fagopyrum/química , Células Hep G2 , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Reguladores de Crescimento de Plantas/síntese química , Reguladores de Crescimento de Plantas/química , Reguladores de Crescimento de Plantas/farmacologia , Pirazinamida/química , Pirazinamida/farmacologia , Pirazinas/síntese química , Pirazinas/química , Estresse Fisiológico/efeitos dos fármacos
18.
Chem Biol Interact ; 394: 110941, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38493910

RESUMO

The current study imposes a new class of organophosphorus (OP)-inhibited cholinesterase reactivators by conceptualizing a family of asymmetric bisoximes with various reactivating scaffolds. Several novel nucleophilic warheads were investigated, putting forward 29 novel reactivating options, by evaluating their nucleophilicity and ability to directly decompose OP compounds. Adopting the so-called zwitterionic strategy, 17 mono-oxime and nine bisoxime reactivators were discovered with major emphasis on the bifunctional-moiety approach. Compounds were compared with clinically used standards and other known experimentally highlighted reactivators. Our results clearly favor the concept of asymmetric bisoximes as leading reactivators in terms of efficacy and versatility. These top-ranked compounds were characterized in detail by reactivation kinetics parameters and evaluated for potential CNS availability. The highlighted molecules 55, 57, and 58 with various reactivating warheads, surpassed the reactivating potency of pralidoxime and several notable uncharged reactivators. The versatility of lead drug candidate 55 was also inspected on OP-inhibited butyrylcholinesterase, revealing a much higher rate compared to existing clinical antidotes.


Assuntos
Butirilcolinesterase , Reativadores da Colinesterase , Intoxicação por Organofosfatos , Oximas , Oximas/química , Oximas/farmacologia , Reativadores da Colinesterase/química , Reativadores da Colinesterase/farmacologia , Butirilcolinesterase/metabolismo , Butirilcolinesterase/química , Humanos , Intoxicação por Organofosfatos/tratamento farmacológico , Acetilcolinesterase/metabolismo , Antídotos/química , Antídotos/farmacologia , Cinética , Inibidores da Colinesterase/química , Inibidores da Colinesterase/farmacologia , Animais , Compostos Organofosforados/química
19.
Biomed Pharmacother ; 173: 116399, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38492439

RESUMO

The search for novel drugs to address the medical needs of Alzheimer's disease (AD) is an ongoing process relying on the discovery of disease-modifying agents. Given the complexity of the disease, such an aim can be pursued by developing so-called multi-target directed ligands (MTDLs) that will impact the disease pathophysiology more comprehensively. Herewith, we contemplated the therapeutic efficacy of an amiridine drug acting as a cholinesterase inhibitor by converting it into a novel class of novel MTDLs. Applying the linking approach, we have paired amiridine as a core building block with memantine/adamantylamine, trolox, and substituted benzothiazole moieties to generate novel MTDLs endowed with additional properties like N-methyl-d-aspartate (NMDA) receptor affinity, antioxidant capacity, and anti-amyloid properties, respectively. The top-ranked amiridine-based compound 5d was also inspected by in silico to reveal the butyrylcholinesterase binding differences with its close structural analogue 5b. Our study provides insight into the discovery of novel amiridine-based drugs by broadening their target-engaged profile from cholinesterase inhibitors towards MTDLs with potential implications in AD therapy.


Assuntos
Doença de Alzheimer , Inibidores da Colinesterase , Humanos , Inibidores da Colinesterase/farmacologia , Inibidores da Colinesterase/uso terapêutico , Inibidores da Colinesterase/química , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Butirilcolinesterase/metabolismo , Aminoquinolinas/uso terapêutico , Acetilcolinesterase/metabolismo , Ligantes
20.
RSC Med Chem ; 15(5): 1601-1625, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38784455

RESUMO

The investigation into human butyrylcholinesterase (hBChE) inhibitors as therapeutic agents for Alzheimer's disease (AD) holds significant promise, addressing both symptomatic relief and disease progression. In the pursuit of novel drug candidates with a selective BChE inhibition pattern, we focused on naturally occurring template structures, specifically Amaryllidaceae alkaloids of the carltonine-type. Herein, we explored a series of compounds implementing an innovative chemical scaffold built on the 3- and 4-benzyloxy-benzylamino chemotype. Notably, compounds 28 (hBChE IC50 = 0.171 ± 0.063 µM) and 33 (hBChE IC50 = 0.167 ± 0.018 µM) emerged as top-ranked hBChE inhibitors. In silico simulations elucidated the binding modes of these compounds within hBChE. CNS availability was predicted using the BBB score algorithm, corroborated by in vitro permeability assessments with the most potent derivatives. Compound 33 was also inspected for aqueous solubility, microsomal and plasma stability. Chemoinformatics analysis validated these hBChE inhibitors for oral administration, indicating favorable gastrointestinal absorption in compliance with Lipinski's and Veber's rules. Safety assessments, crucial for the chronic administration typical in AD treatment, were conducted through cytotoxicity testing on human neuroblastoma (SH-SY5Y) and hepatocellular carcinoma (HepG2) cell lines.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA