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1.
J Chromatogr A ; 1626: 461361, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797840

RESUMO

The alkaloid enantiomers are well-known to have different physiological and pharmacological effects, and to play an important role in enantioselectivity metabolism with enzymes catalysis in tobacco plants. Here, we developed an improved method for simultaneous and high-precision determination of the individual enantiomers of nornicotine, anatabine and anabasine in four tobacco matrices, based on an achiral gas chromatography-nitrogen phosphorus detector (GCNPD) with commonly available Rtx-200 column using (1S)-(-)-camphanic chloride derivatization. The method development consists of the optimization of extraction and derivatization, screening of achiral column, analysis of the fragmentation mechanisms and evaluation of matrix effect (ME). Under the optimized experimental conditions, the current method exhibited excellent detection capability for the alkaloid enantiomers, with coefficients of determination (R2) > 0.9989 and normality test of residuals P > 0.05 in linear regression parameters. The ME can be neglected for the camphanic derivatives. The limit of detection (LOD) and limit of quantitation (LOQ) ranged from 0.087 to 0.24 µg g - 1 and 0.29 to 0.81 µg g - 1, respectively. The recoveries and within-laboratory relative standard deviations (RSDR) were 94.3%~104.2% and 0.51%~3.89%, respectively. The developed method was successfully applied to determine the enantiomeric profiling of cultivars and curing processes. Tobacco cultivars had a significant impact on the nornicotine, anatabine, anabasine concentration and enantiomeric fraction (EF) of (R)-nornicotine, whereas the only significant change induced by the curing processes was an increase in the EF of (R)-anabasine.


Assuntos
Alcaloides/análise , Anabasina/análise , Cromatografia Gasosa/métodos , Nicotina/análogos & derivados , Piridinas/análise , Tabaco/química , Alcaloides/química , Anabasina/química , Hidrocarbonetos Aromáticos com Pontes/química , Cloretos/química , Lactonas/química , Nicotina/análise , Nicotina/química , Piridinas/química , Estereoisomerismo
2.
Nat Commun ; 11(1): 4249, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843618

RESUMO

Aberrant cell cycle machinery and loss of the CDKN2A tumor suppressor locus make CDK4/6 a potential target in pancreatic ductal adenocarcinoma (PDAC). However, a vast majority of PDAC cases do not harbor a durable response to monotherapy of CDK4/6 inhibitor. Utilizing remote loading to co-encapsulate CDK4/6 inhibitor palbociclib (PAL) and an autophagy inhibitor hydroxychloroquine (HCQ), we demonstrate a ratiometrically designed mesoporous silica nanoformulation with synergistic efficacy in subcutaneous and orthotopic PDAC mouse models. The synergism is attributed to the effective intratumoral buildup of PAL/HCQ, which otherwise exhibit distinctly different circulatory and biodistribution profile. PAL/HCQ co-delivery nanoparticles lead to the most effective shrinkage of PDAC compared to various controls, including free drug mixture. Immunohistochemistry reveals that PAL/HCQ co-delivery nanoparticles trigger anti-apoptotic pathway after repetitive intravenous administrations in mice. When combined with a Bcl inhibitor, the performance of co-delivery nanoparticles is further improved, leading to a long-lasting anti-PDAC effect in vivo.


Assuntos
Autofagia/efeitos dos fármacos , Carcinoma Ductal Pancreático/tratamento farmacológico , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Sistemas de Liberação de Medicamentos , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Modelos Animais de Doenças , Sinergismo Farmacológico , Humanos , Hidroxicloroquina/administração & dosagem , Hidroxicloroquina/química , Hidroxicloroquina/farmacologia , Camundongos , Nanopartículas/administração & dosagem , Nanopartículas/química , Piperazinas/administração & dosagem , Piperazinas/química , Piperazinas/farmacologia , Piridinas/administração & dosagem , Piridinas/química , Piridinas/farmacologia , Dióxido de Silício/administração & dosagem , Dióxido de Silício/química , Dióxido de Silício/farmacologia , Resultado do Tratamento
3.
J Chromatogr A ; 1625: 461303, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709346

RESUMO

The chromatographic performances of four coated and immobilized amylose phenylcarbamate-based chiral columns were evaluated and compared under normal phase (NP) elution conditions by using chiral 4,4'-bipyridine derivatives as analytes. n-Hexane/2-propanol 90:10 and n-hexane/2-propanol/methanol 90:5:5 mixtures were employed as mobile phases (MPs), and the effect of adding methanol in the MP on retention and selectivity was considered. The effect of temperature on retention and selectivity was also evaluated, and overall thermodynamic parameters associated with the analyte adsorption onto the CSP surface were derived from van't Hoff plots. Interesting cases of enantiomer elution order (EEO) reversal, which are dependent on the nature of polar modifier, analyte structure, column-type, and temperature, were observed. The impact of substitution pattern and electronic properties of analytes and selectors on the separation behaviour was investigated by correlating chromatographic parameters and molecular properties determined by using density functional theory (DFT) calculations. Both coated and immobilized amylose tris(3,5-dimethylphenylcarbamate) columns allowed for the baseline enantioseparation (2.0 ≤ RS ≤ 4.9) of all 4,4'-bipyridines considered in this study. These results appear particularly useful because both enantiomers of these 4,4'-bipyridine derivatives are currently under investigation as new inhibitors of transthyretin fibrillogenesis, a biochemical phenomenon which is implicated to cause amyloid diseases.


Assuntos
Amilose/química , Piridinas/química , 2-Propanol/química , Adsorção , Hexanos/química , Metanol/química , Modelos Moleculares , Fenilcarbamatos/química , Eletricidade Estática , Estereoisomerismo , Temperatura
4.
J Chromatogr A ; 1624: 461155, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540056

RESUMO

The topic in the present paper is to prepare molecularly imprinted polymer (MIP) using the template molecule with low purity. For the first time, a surrounding of macromolecular crowding was established to promote the formation of the complex of the template with functional monomer efficiently thus highly pure template molecule was unnecessary. In this study, the MIP monolith was synthesized using low purity lactucopicrin as template in place of highly pure one, and polystyrene was used as macromolecular crowding agent. 4-Vinylpyridine and ethyleneglycol dimethacrylate were used as functional monomer and crosslinker, respectively. Polymerization parameters, including the ratio of functional monomer/template, various template concentrations, and PS concentration on the affinity of the resulting MIP were systematically investigated. For the lactucopicrin MIP made with the purity of lactucopicrin of 92%, the imprinting factor can be up to 2.2. The resulting MIP was filled in solid phase extraction (SPE) cartridge to purify lactucopicrin from the crude extract of Cichorium glandulosum Boiss. et Huet. After two cycles of MIP SPE for the crude extract, the highest recovery and purity of lactucopicrin was 64.8% and 97.8%, respectively. The results indicated that the use of macromolecular crowding agent is an effective method for improving the performance of the MIP prepared with the template of low purity, particularly valuable to the cases in which the highly pure target molecule is hard to be obtained.


Assuntos
Impressão Molecular , Polímeros/química , Asteraceae/química , Reagentes para Ligações Cruzadas/química , Lactonas/química , Lactonas/isolamento & purificação , Metacrilatos/química , Polimerização , Poliestirenos/química , Piridinas/química , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Extração em Fase Sólida
5.
Exp Parasitol ; 215: 107933, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32525006

RESUMO

Schistosomiasis is still a public health problem. Praziquantel is the only drug available for treatment of all forms of human schistosomiasis. Although praziquantel is an effective drug against all species of human schistosomes, concerns about resistance have been raised, especially in endemic areas. A hybrid compound containing several pharmacophore within a single molecule is a promising strategy. Here, we described the anti-schistosomal effect of 4-(2-Chloroquinolin-3-yl)-2-oxo-6-(p-tolyl)-1,2-dihydropyridine-3-carbonitrile (PPQ-6), a hybrid drug based on quinoline and pyridine. PPQ-6 was given as two regimens (20 or 40 mg/kg). In both regimens, PPQ-6 significantly reduced liver and spleen indices, nitric oxide production, tissue egg load, hepatic granuloma size and count, immature eggs and total worm burden especially females. Our findings suggested that PPQ-6 is a promising anti-schistosomal agent; however more research is needed to elucidate its mechanism of action and report its activity on juvenile schistosomes and other species of human schistosomes.


Assuntos
Piridinas/farmacologia , Quinolinas/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Esquistossomose mansoni/tratamento farmacológico , Esquistossomicidas/farmacologia , Análise de Variância , Animais , Relação Dose-Resposta a Droga , Feminino , Fígado/parasitologia , Fígado/patologia , Masculino , Camundongos , Óxido Nítrico/análise , Piridinas/química , Piridinas/uso terapêutico , Quinolinas/química , Quinolinas/uso terapêutico , Distribuição Aleatória , Esquistossomicidas/química , Esquistossomicidas/uso terapêutico , Fatores Sexuais , Baço/parasitologia , Baço/patologia
6.
Mol Pharmacol ; 98(2): 168-180, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32474444

RESUMO

The two major nicotinic acetylcholine receptors (nAChRs) in the brain are the α4ß2 and α7 subtypes. A "methyl scan" of the pyrrolidinium ring was used to detect differences in nicotine's interactions with these two receptors. Each methylnicotine was investigated using voltage-clamp and radioligand binding techniques. Methylation at each ring carbon elicited unique changes in nicotine's receptor interactions. Replacing the 1'-N-methyl with an ethyl group or adding a second 1'-N-methyl group significantly reduced interaction with α4ß2 but not α7 receptors. The 2'-methylation uniquely enhanced binding and agonist potency at α7 receptors. Although 3'- and 5'-trans-methylations were much better tolerated by α7 receptors than α4ß2 receptors, 4'-methylation decreased potency and efficacy at α7 receptors much more than at α4ß2 receptors. Whereas cis-5'-methylnicotine lacked agonist activity and displayed a low affinity at both receptors, trans-5'-methylnicotine retained considerable α7 receptor activity. Differences between the two 5'-methylated analogs of the potent pyridyl oxymethylene-bridged nicotine analog A84543 were consistent with what was found for the 5'-methylnicotines. Computer docking of the methylnicotines to the Lymnaea acetylcholine binding protein crystal structure containing two persistent waters predicted most of the changes in receptor affinity that were observed with methylation, particularly the lower affinities of the cis-methylnicotines. The much smaller effects of 1'-, 3'-, and 5'-methylations and the greater effects of 2'- and 4'-methylations on nicotine α7 nAChR interaction might be exploited for the design of new drugs based on the nicotine scaffold. SIGNIFICANCE STATEMENT: Using a comprehensive "methyl scan" approach, we show that the orthosteric binding sites for acetylcholine and nicotine in the two major brain nicotinic acetylcholine receptors interact differently with the pyrrolidinium ring of nicotine, and we suggest reasons for the higher affinity of nicotine for the heteromeric receptor. Potential sites for nicotine structure modification were identified that may be useful in the design of new drugs targeting these receptors.


Assuntos
Nicotina/análogos & derivados , Piridinas/síntese química , Receptores Nicotínicos/metabolismo , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Animais , Sítios de Ligação , Masculino , Metilação , Simulação de Acoplamento Molecular , Estrutura Molecular , Nicotina/química , Piridinas/química , Piridinas/farmacologia , Ratos , Relação Estrutura-Atividade , Xenopus laevis
7.
J Infect Public Health ; 13(9): 1210-1223, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32561274

RESUMO

BACKGROUND: The rapidly enlarging COVID-19 pandemic caused by the novel SARS-corona virus-2 is a global public health emergency of an unprecedented level. Unfortunately no treatment therapy or vaccine is yet available to counter the SARS-CoV-2 infection, which substantiates the need to expand research efforts in this direction. The indispensable function of the main protease in virus replication makes this enzyme a promising target for inhibitors screening and drug discovery to treat novel coronavirus infection. The recently concluded α-ketoamide ligand-bound X-ray crystal structure of SARS-CoV-2 Mpro (PDB ID: 6Y2F) from Zhang et al. has revealed the potential inhibitor binding mechanism and the molecular determinants responsible for substrate binding. METHODS: For the study, we have targeted the SARS-CoV-2 Mpro for the screening of FDA approved antiviral drugs and carried out molecular docking based virtual screening. Further molecular dynamic simulation studies of the top three selected drugs carried out to investigated for their binding affinity and stability in the SARS-CoV-2 Mpro active site. The phylogenetic analysis was also performed to know the relatedness between the SARS-CoV-2 genomes isolated from different countries. RESULTS: The phylogenetic analysis of the SARS-CoV-2 genome reveals that the virus is closely related to the Bat-SL-CoV and does not exhibit any divergence at the genomic level. Molecular docking studies revealed that among the 77 drugs, screened top ten drugs shows good binding affinities, whereas the top three drugs: Lopinavir-Ritonavir, Tipranavir, and Raltegravir were undergone for molecular dynamics simulation studies for their conformational stability in the active site of the SARS-CoV-2 Mpro protein. CONCLUSIONS: In the present study among the library of FDA approved antiviral drugs, the top three inhibitors Lopinavir-Ritonavir, Tipranavir, and Raltegravir show the best molecular interaction with the main protease of SARS-CoV-2. However, the in-vitro efficacy of the drug molecules screened in this study further needs to be corroborated by carrying out a biochemical and structural investigation.


Assuntos
Antivirais/química , Betacoronavirus/enzimologia , Infecções por Coronavirus/tratamento farmacológico , Cisteína Endopeptidases/química , Reposicionamento de Medicamentos , Pneumonia Viral/tratamento farmacológico , Inibidores de Proteases/química , Proteínas não Estruturais Virais/química , Betacoronavirus/genética , Combinação de Medicamentos , Humanos , Lopinavir/química , Conformação Molecular , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Pandemias , Filogenia , Piridinas/química , Pironas/química , Raltegravir Potássico/química , Ritonavir/química , Proteínas não Estruturais Virais/antagonistas & inibidores
8.
Nature ; 585(7824): 293-297, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32494016

RESUMO

Molecular glue compounds induce protein-protein interactions that, in the context of a ubiquitin ligase, lead to protein degradation1. Unlike traditional enzyme inhibitors, these molecular glue degraders act substoichiometrically to catalyse the rapid depletion of previously inaccessible targets2. They are clinically effective and highly sought-after, but have thus far only been discovered serendipitously. Here, through systematically mining databases for correlations between the cytotoxicity of 4,518 clinical and preclinical small molecules and the expression levels of E3 ligase components across hundreds of human cancer cell lines3-5, we identify CR8-a cyclin-dependent kinase (CDK) inhibitor6-as a compound that acts as a molecular glue degrader. The CDK-bound form of CR8 has a solvent-exposed pyridyl moiety that induces the formation of a complex between CDK12-cyclin K and the CUL4 adaptor protein DDB1, bypassing the requirement for a substrate receptor and presenting cyclin K for ubiquitination and degradation. Our studies demonstrate that chemical alteration of surface-exposed moieties can confer gain-of-function glue properties to an inhibitor, and we propose this as a broader strategy through which target-binding molecules could be converted into molecular glues.


Assuntos
Ciclinas/deficiência , Ciclinas/metabolismo , Proteólise/efeitos dos fármacos , Purinas/química , Purinas/farmacologia , Piridinas/química , Piridinas/farmacologia , Linhagem Celular Tumoral , Quinases Ciclina-Dependentes/antagonistas & inibidores , Quinases Ciclina-Dependentes/química , Quinases Ciclina-Dependentes/metabolismo , Ciclinas/química , Proteínas de Ligação a DNA/metabolismo , Humanos , Modelos Moleculares , Complexo de Endopeptidases do Proteassoma/metabolismo , Ligação Proteica/efeitos dos fármacos , Purinas/toxicidade , Piridinas/toxicidade , Bibliotecas de Moléculas Pequenas/análise , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Ubiquitinação/efeitos dos fármacos
9.
Anticancer Res ; 40(5): 2613-2625, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32366406

RESUMO

BACKGROUND/AIM: The occurrence of BRAFV600E mutation causes an up-regulation of the B-raf kinase activity leading to the stabilization of hypoxia-inducible factor 1-alpha (HIF-1α) - the promoter of the 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) enzyme. The aim of the study was to examine the effect of the (2E)-3-(3-Pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO), as an inhibitor of PFKFB3, on human melanoma cells (A375) with endogenous BRAFV600E mutation. MATERIALS AND METHODS: A375 cells were exposed to different concentrations of 3PO and the following tests were performed: docking, cytotoxicity assay, immunocytochemistry staining glucose uptake, clonogenic assay, holotomography imaging, and flow cytometry. RESULTS: Our studies revealed that 3PO presents a dose-dependent and time-independent cytotoxic effect and promotes apoptosis of A375 cells. Furthermore, the obtained data indicate that 3PO induces cell cycle arrest in G1/0 and glucose uptake reduction. CONCLUSION: Taking all together, our research demonstrated a here should be proapoptotic and antiproliferative effect of 3PO on A375 human melanoma cells.


Assuntos
Inibidores Enzimáticos/farmacologia , Melanoma/enzimologia , Fosfofrutoquinase-2/antagonistas & inibidores , Piridinas/farmacologia , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Caspase 8/metabolismo , Domínio Catalítico , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Inibidores Enzimáticos/química , Glucose/metabolismo , Humanos , Melanoma/patologia , Simulação de Acoplamento Molecular , Terapia de Alvo Molecular , Fosfofrutoquinase-2/metabolismo , Piridinas/química , Ensaio Tumoral de Célula-Tronco
10.
Nat Commun ; 11(1): 2569, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32444828

RESUMO

Methods for direct C-H trifluoromethoxylation of arenes and heteroarenes are rare, despite the importance of trifluoromethoxylated compounds for pharmaceuticals, agrochemicals, and material sciences. Especially selective C-H trifluoromethoxylation of pyridines remains a formidable challenge. Here we show a general late-stage C-H trifluoromethoxylation of arenes and heteroarenes as limiting reagent with trifluoromethoxide anion. The reaction is mediated by silver salts under mild reaction conditions, exhibiting broad substrate scope and wide functional-group compatibility. In addition, ortho-position selective C-H trifluoromethoxylation of pyridines is observed. The method is not only applicable to the gram-scale synthesis of trifluoromethoxylated products but also allows efficient late-stage C-H trifluoromethoxylation of marketed small-molecule drugs, common pharmacophores and natural products.


Assuntos
Hidrocarbonetos Fluorados/química , Técnicas de Química Sintética , Piridinas/química , Compostos de Prata/química
11.
Phytomedicine ; 71: 153239, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32447245

RESUMO

BACKGROUND AND PURPOSE: Multidrug resistance (MDR) remains the main obstacle in cancer treatment and overexpression of P-glycoprotein (P-gp) is one of the most common causes of chemoresistance. The development of novel P-gp inhibitors from natural products is a prospective strategy to combat MDR cancers. Among the natural sesquiterpene compounds, sesquiterpene pyridine alkaloids exhibit various biological properties. Therefore, in the present study, we evaluated the modulatory effects of wilforine on P-gp expression and function. The molecular mechanisms and kinetic models of wilforine-mediated P-gp inhibition were further investigated. METHODS: The human P-gp stable expression cells (ABCB1/Flp-InTM-293) and human cervical cancer cells (sensitive: HeLaS3; MDR: KBvin) were used. The cell viability was assessed by SRB assay. The inhibitory effect of wilforine on P-gp efflux and the underlying mechanism were evaluated by assays for calcein-AM uptake, rhodamine123 and doxorubicin efflux, ATPase activity, real-time quantitative RT-PCR, apoptosis, and cell cycle analysis. Molecular docking was performed by the docking software CDOCKER with BIOVIA Discovery Studio 4.5 (D.S. 4.5). RESULTS: We found that wilforine significantly inhibited the efflux activity of P-gp in a concentration-dependent manner. Further kinetic analysis demonstrated that wilforine significantly inhibited P-gp efflux function by competitive inhibition and stimulated the basal P-gp ATPase activity. In addition, wilforine re-sensitized MDR cancer cells to chemotherapeutic drugs. The docking model indicated that wilforine was bound to residues of P-gp such as LEU884, LYS887, THR176 and ASN172. CONCLUSION: These results suggest a novel future therapeutic strategy for MDR cancer using wilforine as an adjuvant treatment with chemotherapy.


Assuntos
Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Lactonas/farmacologia , Piridinas/farmacologia , Subfamília B de Transportador de Cassetes de Ligação de ATP/antagonistas & inibidores , Subfamília B de Transportador de Cassetes de Ligação de ATP/química , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Resistencia a Medicamentos Antineoplásicos/fisiologia , Células HeLa , Humanos , Cinética , Lactonas/química , Simulação de Acoplamento Molecular , Estudos Prospectivos , Piridinas/química
12.
Mol Pharmacol ; 98(1): 49-60, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32358164

RESUMO

Negative allosteric modulation of the metabotropic glutamate 5 (mGlu5) receptor has emerged as a potential strategy for the treatment of neurologic disorders. Despite the success in preclinical studies, many mGlu5 negative allosteric modulators (NAMs) that have reached clinical trials failed due to lack of efficacy. In this study, we provide a detailed in vitro pharmacological characterization of nine clinically and preclinically tested NAMs. We evaluated inhibition of l-glutamate-induced signaling with Ca2+ mobilization, inositol monophosphate (IP1) accumulation, extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation, and real-time receptor internalization assays on rat mGlu5 expressed in HEK293A cells. Moreover, we determined association rates (kon) and dissociation rates (koff), as well as NAM affinities with [3H]methoxy-PEPy binding experiments. kon and koff values varied greatly between the nine NAMs (34- and 139-fold, respectively) resulting in long receptor residence times (>400 min) for basimglurant and mavoglurant, medium residence times (10-30 min) for AZD2066, remeglurant, and (RS)-remeglurant, and low residence times (<10 mins) for dipraglurant, F169521, F1699611, and STX107. We found that all NAMs inhibited l-glutamate-induced mGlu5 receptor internalization, generally with a similar potency to IP1 accumulation and ERK1/2 phosphorylation, whereas Ca2+ mobilization was less potently inhibited. Operational model of allosterism analyses revealed that dipraglurant and (RS)-remeglurant were biased toward (affinity) receptor internalization and away (cooperativity) from the ERK1/2 phosphorylation pathway, respectively. Our study is the first to measure mGlu5 NAM binding kinetics and negative allosteric modulation of mGlu5 receptor internalization and adds significant new knowledge about the molecular pharmacology of a diverse range of clinically relevant NAMs. SIGNIFICANCE STATEMENT: The metabotropic glutamate 5 (mGlu5) receptor is important in many brain functions and implicated in several neurological pathologies. Negative allosteric modulators (NAMs) have shown promising results in preclinical models but have so far failed in human clinical trials. Here we provide the most comprehensive and comparative molecular pharmacological study to date of nine preclinically/clinically tested NAMs at the mGlu5 receptor, which is also the first study to measure ligand binding kinetics and negative allosteric modulation of mGlu5 receptor internalization.


Assuntos
Imidazóis/farmacologia , Indóis/farmacologia , Isoxazóis/farmacologia , Piridinas/farmacologia , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Triazóis/farmacologia , Regulação Alostérica/efeitos dos fármacos , Animais , Cálcio/metabolismo , Células HEK293 , Humanos , Imidazóis/química , Indóis/química , Fosfatos de Inositol/metabolismo , Isoxazóis/química , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Estrutura Molecular , Fosforilação/efeitos dos fármacos , Piridinas/química , Ratos , Fatores de Tempo , Triazóis/química
13.
Food Chem ; 328: 127100, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32464558

RESUMO

Pyridines are produced during food processing and are important flavor compounds. In spite of that, their formation pathways are still poorly understood, in particular those related to 3-hydroxypyridines. In an attempt to fill this gap, this study describes, for the first time, precursors and reaction pathways leading to 3-hydroxypyridine formation. 3-Hydroxypyridines are produced by reaction of lipid-derived reactive carbonyls and ammonia-producing compounds and were studied by using gas chromatography coupled to mass spectrometry. Their main precursors resulted to be 4,5-epoxy-2-alkenals and 2,4-alkadienals. 3-Hydroxypyridines were produced at temperatures higher than 100 °C, at slightly basic pH values, and with an activation energy of about 50 kJ/mol. A reaction pathway that explains their formation in the course of the lipid oxidation pathway is proposed. The role of lipid oxidation on the production of 3-hydroxypyridines was confirmed by studying their formation in oxidized linseed and menhaden oils heated in the presence of glutamine.


Assuntos
Amônia/química , Manipulação de Alimentos , Lipídeos/química , Piridinas/química , Temperatura Alta , Óleo de Semente do Linho/química , Oxirredução
14.
Chemistry ; 26(34): 7595-7601, 2020 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-32302020

RESUMO

We propose post-metalation modification as a useful strategy to control the guest recognition behavior of a metal-containing macrocyclic host. This is based on the ligand exchange of the axial ligands of a cobalt(III) dinuclear macrocyclic host, [LCo2 X4 ]2+ (X=axial amine ligand). Four piperidine ligands in [LCo2 (pip)4 ]2+ (pip=piperidine) were site-selectively replaced with primary amines. The competitive experiments revealed that the order of the affinity toward the cobalt centers in [LCo2 X4 ]2+ is primary amine > secondary amine > tertiary amine and that the piperidine-coordinating complex, [LCo2 (pip)4 ]2+ , was reasonably reactive among the isolable complexes. Indeed, two piperidine ligands at the diagonal positions in [LCo2 (pip)4 ]2+ were site-selectively replaced with pyridine or acetate ion. The replacement of piperidine with acetate ion significantly enhanced the recognition ability towards Na+ .


Assuntos
Aminas/química , Cobalto/química , Complexos de Coordenação/química , Piridinas/química , Complexos de Coordenação/síntese química , Cristalografia por Raios X , Ligantes , Metais , Estrutura Molecular
15.
Bull Environ Contam Toxicol ; 104(4): 497-502, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32152685

RESUMO

The effect of vermicompost added to a loam soil on the leaching behaviour of two herbicides (triclopyr and fluroxypyr) was examined. Mobility of the herbicides was assessed using disturbed soil columns under laboratory conditions. In both cases, the addition of vermicompost significantly increased the sorption of the compounds. For both, DT50 values were slightly higher in the amended soil, due to the increased adsorption. Rate constants (k) calculated according to pseudo-first order model were significantly lower in the case of triclopyr (very persistent), which led to a much lower degradation rate compared to fluroxypyr (persistent) in both unamended and amended soils. Values calculated for the experimental leaching index (ELI) in unamended and amended soils showed medium and high leachability for fluroxypyr (0.31 and 0.29) and triclopyr (0.72 and 0.70), respectively. Other index-based screening models (GUS, RLPI, LIX) also catalogue both herbicides as potential leachers. Results confirm that triclopyr and fluroxypyr may contaminate groundwater resources.


Assuntos
Acetatos/análise , Compostagem , Glicolatos/análise , Água Subterrânea/química , Modelos Teóricos , Piridinas/análise , Poluentes do Solo/análise , Solo/química , Acetatos/química , Adsorção , Glicolatos/química , Herbicidas/análise , Herbicidas/química , Piridinas/química , Poluentes do Solo/química
16.
J Med Chem ; 63(6): 2915-2929, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32134643

RESUMO

To identify Janus kinase (JAK) inhibitors that selectively target gastrointestinal tissues with limited systemic exposures, a class of imidazopyrrolopyridines with a range of physical properties was prepared and evaluated. We identified compounds with low intrinsic permeability and determined a correlation between permeability and physicochemical properties, clogP and tPSA, for a subset of compounds. This low intrinsic permeability translated into compounds displaying high colonic exposure and low systemic exposure after oral dosing at 25 mg/kg in mouse. In a mouse PK/PD model, oral dosing of lead compound 2 demonstrated dose-dependent inhibition of pSTAT phosphorylation in colonic explants post-oral dose but low systemic exposure and no measurable systemic pharmacodynamic activity. We thus demonstrate the utility of JAK inhibitors with low intrinsic permeability as a feasible approach to develop gut-restricted, pharmacologically active molecules with a potential advantage over systemically available compounds that are limited by systemic on-target adverse events.


Assuntos
Doenças Inflamatórias Intestinais/tratamento farmacológico , Inibidores de Janus Quinases/farmacologia , Inibidores de Janus Quinases/farmacocinética , Piridinas/farmacologia , Piridinas/farmacocinética , Administração Oral , Animais , Cães , Descoberta de Drogas , Feminino , Humanos , Doenças Inflamatórias Intestinais/metabolismo , Inibidores de Janus Quinases/administração & dosagem , Inibidores de Janus Quinases/química , Janus Quinases/antagonistas & inibidores , Janus Quinases/metabolismo , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos C57BL , Permeabilidade , Fosforilação/efeitos dos fármacos , Piridinas/administração & dosagem , Piridinas/química
17.
J Chromatogr A ; 1620: 461004, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32143875

RESUMO

In the present study, a fast multiresidue method determining three novel fungicides fenpicoxamid, isofetamid, and mandestrobin in cereals was developed and validated for the first time using ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Samples were extracted by QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology, and cleaned up using the disposable pipette extraction (DPX) tips containing primary secondary amine (PSA) and silica gel modified with zirconium oxide (Z-Sep) in less than 1 min. Linearity (r > 0.99) of three fungicides in the calibration range of 0.001-0.1 µg mL-1 was satisfactory. Mean recoveries (n = 15) from all matrices were between 84.8% and 100.3% as the corresponding intra-day and inter-day relative standard deviations (RSDs) were less than 10.6%. Limits of quantitation (LOQs) of all analytes in different matrices were defined at 0.01 mg kg-1. The results indicate this method can serve as a sensitive and rapid approach to monitoring contents of fenpicoxamid, isofetamid, and mandestrobin in cereals.


Assuntos
Acetamidas/análise , Cromatografia Líquida de Alta Pressão/métodos , Grão Comestível/química , Fungicidas Industriais/análise , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Tiofenos/análise , Fracionamento Químico/instrumentação , Fungicidas Industriais/química , Fungicidas Industriais/isolamento & purificação , Lactonas/análise , Lactonas/química , Lactonas/isolamento & purificação , Resíduos de Praguicidas/química , Resíduos de Praguicidas/isolamento & purificação , Piridinas/análise , Piridinas/química , Piridinas/isolamento & purificação , Zircônio/química
18.
PLoS One ; 15(2): e0227811, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32023266

RESUMO

Anopheles darlingi is the main vector of malaria in Brazil, characterized by a high level of anthropophilia and endophagy. Imidacloprid, thiacloprid, and acetamiprid are the most widespread insecticides of the neonicotinoid group. However, they produce adverse effects on the non-target insects. Flupyradifurone has been marketed as an alternative to non-fluorinated neonicotinoids. Neonicotinoids containing trifluoroacethyl substituent reveal increased insecticidal activity due to higher hydrophobicity and metabolic stability. We synthesized novel neonicotinoid insecticides containing fluorinated acceptor groups and their interactions were estimated with the nicotinic acetylcholine receptor (nAChR) binding site by molecular docking studies, to evaluate their larvicidal activity against A. darlingi, and to assess their outdoor photodegradation behavior. New neonicotinoid analogues were prepared and characterized by NMR and mass-spectrometry. The synthesized molecules were modelled by time-dependent density functional theory and analyzed, their interaction with nAChR was investigated by molecular docking. Their insecticide activity was tested on Anopheles larvae collected in suburban area of Manaus, Brazil. Four new fluorinated neonicotinoid analogs were prepared and tested against 3rd instars larvae of A. darlingi showing high larvicidal activity. Docking studies reveal binding modes of the synthesized compounds and suggest that their insecticidal potency is governed by specific interactions with the receptor binding site and enhanced lipophilicity. 2-Chloro-5-(2-trifluoromethyl-pyrrolidin-1-ylmethyl)pyridine 5 showed fast degradation in water maintaining high larvicidal activity. All obtained substances possessed high larvicidal activity in low concentrations in 48 hours of exposure, compared to commercial flupyradifurone. Such activity is connected to a unique binding pattern of the synthesized compounds to insect's nAChR and to their enhanced bioavailability owing to introduction of fluorinated amino-moieties. Therefore, the compounds in question have a high potential for application as control agents for insects transmitting tropical diseases, and they will be less persistent in the environment.


Assuntos
Anopheles/efeitos dos fármacos , Halogenação , Inseticidas/toxicidade , Simulação de Acoplamento Molecular , Neonicotinoides/toxicidade , 4-Butirolactona/análogos & derivados , 4-Butirolactona/química , 4-Butirolactona/toxicidade , Animais , Inseticidas/química , Larva/efeitos dos fármacos , Neonicotinoides/síntese química , Neonicotinoides/química , Piridinas/química , Piridinas/toxicidade , Espectrofotometria Ultravioleta , Eletricidade Estática
19.
J Med Chem ; 63(5): 2620-2637, 2020 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-32081010

RESUMO

The standard of care for HIV-1 infection, highly active antiretroviral therapy (HAART), combines two or more drugs from at least two classes. Even with the success of HAART, new drugs with novel mechanisms are needed to combat viral resistance, improve adherence, and mitigate toxicities. Active site inhibitors of HIV-1 integrase are clinically validated for the treatment of HIV-1 infection. Here we describe allosteric inhibitors of HIV-1 integrase that bind to the LEDGF/p75 interaction site and disrupt the structure of the integrase multimer that is required for the HIV-1 maturation. A series of pyrazolopyrimidine-based inhibitors was developed with a vector in the 2-position that was optimized by structure-guided compound design. This resulted in the discovery of pyrazolopyrimidine 3, which was optimized at the 2- and 7-positions to afford 26 and 29 as potent allosteric inhibitors of HIV-1 integrase that exhibited low nanomolar antiviral potency in cell culture and encouraging PK properties.


Assuntos
Regulação Alostérica/efeitos dos fármacos , Inibidores de Integrase de HIV/química , Inibidores de Integrase de HIV/farmacologia , HIV-1/efeitos dos fármacos , Pirazóis/química , Pirazóis/farmacologia , Piridinas/química , Piridinas/farmacologia , Administração Oral , Animais , Descoberta de Drogas , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , Integrase de HIV/metabolismo , Inibidores de Integrase de HIV/administração & dosagem , Inibidores de Integrase de HIV/farmacocinética , Humanos , Masculino , Simulação de Acoplamento Molecular , Pirazóis/administração & dosagem , Pirazóis/farmacocinética , Piridinas/administração & dosagem , Piridinas/farmacocinética , Ratos Sprague-Dawley
20.
J Med Chem ; 63(5): 2411-2425, 2020 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-32101422

RESUMO

The measurement of receptor occupancy (RO) using positron emission tomography (PET) has been instrumental in guiding discovery and development of CNS directed therapeutics. We and others have investigated muscarinic acetylcholine receptor 4 (M4) positive allosteric modulators (PAMs) for the treatment of symptoms associated with neuropsychiatric disorders. In this article, we describe the synthesis, in vitro, and in vivo characterization of a series of central pyridine-related M4 PAMs that can be conveniently radiolabeled with carbon-11 as PET tracers for the in vivo imaging of an allosteric binding site of the M4 receptor. We first demonstrated its feasibility by mapping the receptor distribution in mouse brain and confirming that a lead molecule 1 binds selectively to the receptor only in the presence of the orthosteric agonist carbachol. Through a competitive binding affinity assay and a number of physiochemical properties filters, several related compounds were identified as candidates for in vivo evaluation. These candidates were then radiolabeled with 11C and studied in vivo in rhesus monkeys. This research eventually led to the discovery of the clinical radiotracer candidate [11C]MK-6884.


Assuntos
Regulação Alostérica/efeitos dos fármacos , Agonistas Muscarínicos/farmacologia , Piridinas/farmacologia , Receptor Muscarínico M4/agonistas , Animais , Células CHO , Radioisótopos de Carbono/química , Radioisótopos de Carbono/farmacologia , Cricetulus , Humanos , Macaca mulatta , Agonistas Muscarínicos/química , Doenças Neurodegenerativas/diagnóstico por imagem , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/metabolismo , Tomografia por Emissão de Pósitrons , Piridinas/química , Receptor Muscarínico M4/metabolismo
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