Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.314
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-32004940

RESUMO

Flibanserin (FLB) is the first FDA approved drug showed to have significant activity against sexual desire disorder of premenopausal and postmenopausal women. Unfortunately, FLB is used as an adulterant in dietary supplement products as a performance enhancer in sports. Identification of FLB and its metabolites in the biological samples requires an authenticated analytical technique. The aim of this study was to identify N-oxide metabolite of FLB in microsomal and S9 human liver enzyme fractions, rat urine and feces. There are several N-oxide reported as genotoxic impurity or reactive metabolites based on position of N-oxide in piperazine ring. This study also describes the strategy to utilize degradation chemistry for isolation of N-oxide and its step-wise characterization. An LC-MS method has been developed and employed for identifying the N-oxide metabolite of FLB. The targeted N-oxide metabolite in the extracted ion chromatogram of the in vitro and in vivo samples has been confirmed by analyzing the changes in observed mass at m/z 407.1693. Major distinguished abundant ions at m/z 243.1104, 190.0974, 161.0705, 119.0601 confirmed the structure of the metabolite. This study will help to understand the oxidative potential of FLB in toxicokinetic study. The developed method can be useful to identify FLB or its N-oxide metabolite in dope testing in future. This is the first time to report a strategy to utilize degradation chemistry for N-oxide metabolite characterization. In this study, isolated N-oxidative degradation product was used to confirm N-oxide metabolite which was characterized by LC-MS through H/D exchange and structure was ensured by NMR spectroscopy (1H, COSY).


Assuntos
Benzimidazóis , Medição da Troca de Deutério/métodos , Fezes/química , Espectrometria de Massas em Tandem/métodos , Administração Oral , Animais , Benzimidazóis/administração & dosagem , Benzimidazóis/análise , Benzimidazóis/química , Benzimidazóis/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Espectroscopia de Ressonância Magnética , Masculino , Oxirredução , Ratos , Ratos Sprague-Dawley
2.
Environ Sci Pollut Res Int ; 27(1): 899-906, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31820249

RESUMO

Residue analysis to detect thiophanate-methyl and its primary metabolite (carbendazim) during oyster mushroom (Pleurotus ostreatus var. florida) cultivation was done for two consecutive years 2017 and 2018. Wheat straw substrate was chemically treated with different treatments of thiophate-methyl, viz, thiophanate-methyl 30 ppm + formalin 500 ppm (T1), thiophanate-methyl 40 ppm + formalin 500 ppm (T2), thiophanate-methyl 50 ppm + formalin 500 ppm (T3), thiophanate-methyl 60 ppm + formalin 500 ppm (T4), and formalin 500 ppm (T5 as control and recommended concentration), and utilized for cultivation of oyster mushroom. Treatments T3 and T4 exhibited significant difference in pH levels during both the trials. Minimum spawn run, pinhead formation, and fruit body formation time were recorded in treatments T3 and T4. Significantly higher biological efficiency (%) was recorded in treatments T3 and T4 as compared with all other treatments. No incidence of competitor molds was recorded in T3 and T4. Pesticide residue analysis for detection of thiophanate-methyl and its metabolite (carbendazim) was done in the fruit body produced in T3 and T4 treatments using liquid chromatography with tandem mass spectrometry method. No residue of thiophanate-methyl and carbendazim was detected at 50 ppm concentration of thiophanate-methyl during both the trials. However, in trial II, residue of carbendazim (5.39 µg/kg) was detected at 60 ppm. Based on the findings of the trials I and II, T3 (thiophanate-methyl 50 ppm + formalin 500 ppm) may be utilized for substrate sterilization for oyster mushroom cultivation and Pleurotus ostreatus var. florida could be recognized as microorganism which could play a role in degradation of thiophanate-methyl.


Assuntos
Benzimidazóis/metabolismo , Biodegradação Ambiental , Carbamatos/metabolismo , Pleurotus/metabolismo , Cromatografia Líquida/métodos , Frutas/química , Resíduos de Praguicidas/análise , Poaceae , Esterilização , Espectrometria de Massas em Tandem/métodos , Tiofanato/química , Triticum
3.
Dalton Trans ; 48(37): 14027-14035, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31490509

RESUMO

Au(iii) compounds bearing N,N-pyridylbenzimidazole derivatives with the ethyl (1) or propyl sulfonate (2) appendage react with the model protein hen egg white lysozyme (HEWL), forming adducts with different gold-containing fragments. The conformation of the enzyme, the exact gold binding sites and the oxidation state of Au in the adducts are unknown. Here we report a structural study on the reaction of 1 and 2 with HEWL in solution and solid state. In agreement with previously reported electrospray ionization mass spectra, the compounds degrade in their interaction with the protein. In the structure derived from HEWL crystals exposed to 1 for less than one day, three Au binding sites were identified: Au(i) ions are bound to the side chain of His15 and to the side chains of His15 and Asn93. The third gold centre is buried in the hydrophobic pocket of the protein via the binding to the side chain of Met105 and the trapping between the side chains of Trp28, Trp108 and Trp111. In a second crystal fished three hours later from the same drop, only one Au ion, probably in the +1 oxidation state, is observed; it binds the protein close to the side chains of Asn93 and His15. After three days of soaking, the colour of HEWL crystals obtained in the presence of 1 turned violet. In these crystals, anomalous signals attributable to Au are found on the protein surface; gold atoms are not directly coordinated to residue side chains. Longer exposure of HEWL crystals to 1 produces gold-free crystals. In the adduct of HEWL exposed to 2 for one day, three Au(i) ions are detected close to the side chains of both Asn93 and His15, the side chain of His15 and that of Met105. Longer exposure of HEWL crystals to 2 affords gold-free crystals. These structural data and those of the other protein/gold adducts available at the Protein Data Bank suggest that the reduction of Au(iii) into Au(i) is the basis of the mechanism of action of the biologically active gold(iii) compounds. Besides, Au(i) ions can undergo disproportionation into Au(iii) and Au(0) that can diffuse away from the protein crystals.


Assuntos
Benzimidazóis/química , Ouro/química , Muramidase/química , Compostos Organoáuricos/química , Animais , Benzimidazóis/metabolismo , Sítios de Ligação , Galinhas , Cristalografia por Raios X , Ouro/metabolismo , Modelos Moleculares , Estrutura Molecular , Muramidase/metabolismo , Compostos Organoáuricos/metabolismo
4.
Int J Mol Sci ; 20(18)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487790

RESUMO

Benzimidazole derivatives have a diverse range of biological activities, including antiulcer, antihypertensive, antiviral, antifungal, anti-inflammatory, and anticancer. Despite these activities, previous studies have revealed that some of the derivatives can induce mutations. This study aimed to screen for potential mutagenic activities of novel benzimidazole derivatives 1-4 using the Ames test and to study their structure-activity relationship (SAR). An Ames test was carried out on two strains of Salmonella typhimurium (TA98 and TA100) in the absence and presence of metabolic activation. Genetic analysis was performed prior to the Ames test to determine the genotypes of the bacterial tester strains. Both bacterial strains showed dependency on histidine with the presence of rfa mutation, uvrB deletion, and plasmid pKM101. Further, all derivatives tested showed no mutagenic activity in the absence of metabolic activation in both tester strains. However, in the presence of metabolic activation, compound 1 appeared to induce mutation at 2.5 µg/plate when tested against the TA98 strain. These results suggest that the absence of the -OH group at the ortho-position over the phenyl ring might be the cause of increased mutagenic activity in compound 1. Additionally, the presence of mutagenic activity in compound 1 when it was metabolically activated indicates that this compound is a promutagen.


Assuntos
Benzimidazóis/química , Resistência Microbiana a Medicamentos/genética , Mutagênicos/química , Ativação Metabólica , Benzimidazóis/metabolismo , Benzimidazóis/toxicidade , Genótipo , Mutagênicos/metabolismo , Mutagênicos/toxicidade , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Relação Estrutura-Atividade
5.
Infez Med ; 27(3): 239-250, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31545767

RESUMO

After a long period of interferon-and ribavirin-based therapy (IFN/RBV), a very fast evolution in the development of directly acting antivirals (DAAs) has now established a totally new paradigm for the treatment chronic HCV infection. An efficacy rate within the 95-100% interval, safer and more tolerable drugs, much shorter treatment duration and a quicker establishment of the sustained virological response (SVR) are among the most relevant properties of new DAAs as compared to former IFN/RBV therapies. The last wave of DAAs is also characterized by a lesser tendency to generate or being victim of drug-drug interactions. Nevertheless, since the circumstances in which patients are also recipients of other medications are rather frequent, individualization of treatment is advised in order to minimize the risk of drug-drug interactions of clinical relevance. Three two-drug regimens are available in Italy for the treatment of chronic HCV infection: sofosbuvir/velpatasvir (SOF/VEL), glecaprevir/pibrentasvir (GLE/PIB) and grazoprevir/elbasvir (GZP/RLB). Based on the officially released summary of product characteristics (SmPC) of these three co-formulated dual regimens, we performed a comparative analysis concerning the drug-drug interactions possibly affecting the DAA regimens. According to specific individual conditions, including co-morbidities, the choice of the most appropriate regimen must carefully take into account, among the different variables, the metabolic profile of both DAAs and concurrent medications. The differences among the three regimens offer the possibility to avoid the occurrence of clinically relevant drug-drug interactions in most circumstance.


Assuntos
Antivirais/farmacologia , Benzimidazóis/farmacologia , Benzofuranos/farmacologia , Carbamatos/farmacologia , Hepatite C Crônica/tratamento farmacológico , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Imidazóis/farmacologia , Pirrolidinas/farmacologia , Quinoxalinas/farmacologia , Sofosbuvir/farmacologia , Sulfonamidas/farmacologia , Antivirais/metabolismo , Antivirais/uso terapêutico , Benzimidazóis/metabolismo , Benzofuranos/metabolismo , Carbamatos/metabolismo , Combinação de Medicamentos , Interações Medicamentosas , Hepatite C Crônica/metabolismo , Compostos Heterocíclicos de 4 ou mais Anéis/metabolismo , Humanos , Imidazóis/metabolismo , Interferon-alfa/uso terapêutico , Itália , Polimedicação , Pirrolidinas/metabolismo , Quinoxalinas/metabolismo , Sofosbuvir/metabolismo , Sulfonamidas/metabolismo
6.
Acta Pharmacol Sin ; 40(11): 1466-1479, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31316176

RESUMO

Recently, inhibitor of apoptosis proteins (IAPs) and some IAP antagonists were found to regulate autophagy, but the underlying mechanisms remain unclear. WX20120108 is an analogue of GDC-0152 (a known IAP antagonist) and displays more potent anti-tumor and autophagy-regulating activity in tumor cells, we investigated the regulatory mechanisms underlying WX20120108-induced autophagy. Using molecular docking and fluorescence polarization anisotropy (FPA) competitive assay, we first demonstrated that WX20120108, acting as an IAP antagonist, bound to the XIAP-BIR3, XIAP BIR2-BIR3, cIAP1 BIR3, and cIAP2 BIR3 domains with high affinities. In six cancer cell lines, WX20120108 inhibited the cell proliferation with potencies two to ten-fold higher than that of GDC-0152. In HeLa and MDA-MB-231 cells, WX20120108 induced caspase-dependent apoptosis and activated TNFα-dependent extrinsic apoptosis. On the other hand, WX20120108 induced autophagy in HeLa and MDA-MB-231 cells in dose- and time-dependent manners. We revealed that WX20120108 selectively activated Foxo3, evidenced by Foxo3 nuclear translocation in both gene modified cell line and HeLa cells, as well as the upregulated expression of Foxo3-targeted genes (Bnip3, Pik3c3, Atg5, and Atg4b), which played a key role in autophagy initiation. WX20120108-induced autophagy was significantly suppressed when Foxo3 gene was silenced. WX20120108 dose-dependently increased the generation of reactive oxygen species (ROS) in HeLa cells, and WX20120108-induced Foxo3 activation was completely blocked in the presence of catalase, a known ROS scavenger. However, WX20120108-induced ROS generation was not affected by cIAP1/2 or XIAP gene silencing. In conclusion, WX20120108-induced autophagy relies on activating ROS-Foxo3 pathway, which is independent of IAPs. This finding provides a new insight into the mechanism of IAP antagonist-mediated regulation of autophagy.


Assuntos
Antineoplásicos/farmacologia , Autofagia/efeitos dos fármacos , Benzimidazóis/farmacologia , Dipeptídeos/farmacologia , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Antineoplásicos/metabolismo , Proteína 3 com Repetições IAP de Baculovírus/química , Proteína 3 com Repetições IAP de Baculovírus/metabolismo , Benzimidazóis/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dipeptídeos/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Humanos , Simulação de Acoplamento Molecular , Ligação Proteica , Domínios Proteicos , Espécies Reativas de Oxigênio/metabolismo , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/química , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo
7.
J Pharmacol Sci ; 140(2): 193-196, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31235271

RESUMO

We tested whether NNC 55-0396 (NNC), a T-type calcium channel (T-channel) blocker, reduces the brain injury caused by middle cerebral artery occlusion and reperfusion (MCAO/R) in mice. NNC, administered i.c.v. before the occlusion, greatly reduced the MCAO/R-induced brain infarct and neurological dysfunctions, although it, given toward the end of occlusion, was less effective. Systemic administration of NNC before the occlusion also attenuated the infarct and neurological dysfunctions. Our data imply that blood-brain-barrier-permeable T-channel blockers such as NNC are capable of reducing MCAO/R-induced brain damage, and that T-channels are involved in neuronal damage induced by ischemia rather than reperfusion.


Assuntos
Benzimidazóis/administração & dosagem , Lesões Encefálicas/etiologia , Lesões Encefálicas/prevenção & controle , Bloqueadores dos Canais de Cálcio/administração & dosagem , Ciclopropanos/administração & dosagem , Infarto da Artéria Cerebral Média/complicações , Naftalenos/administração & dosagem , Traumatismo por Reperfusão/complicações , Animais , Benzimidazóis/metabolismo , Barreira Hematoencefálica/metabolismo , Bloqueadores dos Canais de Cálcio/metabolismo , Canais de Cálcio Tipo T/fisiologia , Ciclopropanos/metabolismo , Infusões Intraventriculares , Infusões Parenterais , Masculino , Camundongos Endogâmicos , Naftalenos/metabolismo , Fatores de Tempo
8.
Exp Parasitol ; 204: 107718, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31201779

RESUMO

The aim of the current work was to evaluate a potential pharmacokinetic interaction between the flukicide triclabendazole (TCBZ) and the broad-spectrum benzimidazole (BZD) anthelmintic oxfendazole (OFZ) in sheep. To this end, both an in vitro assay in microsomal fractions and an in vivo trial in lambs parasitized with Haemonchus contortus resistant to OFZ and its reduced derivative fenbendazole (FBZ) were carried out. Sheep microsomal fractions were incubated together with OFZ, FBZ, TCBZ, or a combination of either FBZ and TCBZ or OFZ and TCBZ. OFZ production was significantly diminished upon coincubation of FBZ and TCBZ, whereas neither FBZ nor OFZ affected the S-oxidation of TCBZ towards its sulfoxide and sulfone metabolites. For the in vivo trial, lambs were treated with OFZ (Vermox® oral drench at a single dose of 5 mg/kg PO), TCBZ (Fasinex® oral drench at a single dose of 12 mg/kg PO) or both compounds at a single dose of 5 (Vermox®) and 12 mg/kg (Fasinex®) PO. Blood samples were taken to quantify drug and metabolite concentrations, and pharmacokinetic parameters were calculated by means of non-compartmental analysis. Results showed that the pharmacokinetic parameters of active molecules and metabolites were not significantly altered upon coadministration. The sole exception was the increase in the mean residence time (MRT) of OFZ and FBZ sulfone upon coadministration, with no significant changes in the remaining pharmacokinetic parameters. This research is a further contribution to the study of metabolic drug-drug interactions that may affect anthelmintic efficacies in ruminants.


Assuntos
Anti-Helmínticos/farmacocinética , Benzimidazóis/farmacocinética , Triclabendazol/farmacocinética , Animais , Anti-Helmínticos/metabolismo , Área Sob a Curva , Benzimidazóis/metabolismo , Biotransformação , Sistema Enzimático do Citocromo P-450/metabolismo , Interações Medicamentosas , Fenbendazol/metabolismo , Fígado/metabolismo , Masculino , Microssomos Hepáticos/metabolismo , Oxigenases/metabolismo , Ovinos , Triclabendazol/metabolismo
9.
J Agric Food Chem ; 67(24): 6683-6690, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31140797

RESUMO

Fungicides are frequently detected in natural water and have gained increasing attention as a result of their potential toxicity to non-target aquatic organisms. Carbendazim (CAR), a commonly used fungicide, was selected to explore its toxicity and biodegradation in a typical freshwater diatom Navicula sp. Results showed that the growth of Navicula sp. was inhibited by CAR, with a 24 h EC50 value of 2.18 mg L-1. Although the algal growth rate was recovered after 72 h of exposure, the chlorophyll a content remained significantly decreased when the concentration of CAR was above 0.5 mg L-1. Moreover, Navicula sp. had a negative effect on the removal of CAR, and the acute toxicity by CAR was likely due to its rapid accumulation in algal cells. Mass spectrometric data revealed the transformation products of CAR from hydroxylation, methylation, decarboxylation, demethylation, and deamination in algal cultures. These results provide a better understanding of the environmental risks of CAR in water and point to the need for additional studies on the potential adverse biological effects of its intermediates.


Assuntos
Benzimidazóis/metabolismo , Carbamatos/metabolismo , Diatomáceas/metabolismo , Fungicidas Industriais/metabolismo , Poluentes Químicos da Água/metabolismo , Benzimidazóis/química , Benzimidazóis/toxicidade , Carbamatos/química , Carbamatos/toxicidade , Diatomáceas/química , Diatomáceas/efeitos dos fármacos , Diatomáceas/crescimento & desenvolvimento , Água Doce/análise , Fungicidas Industriais/química , Fungicidas Industriais/toxicidade , Espectrometria de Massas , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade
10.
ChemMedChem ; 14(13): 1291-1302, 2019 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-31131561

RESUMO

We embarked on a structural optimization campaign aimed at the discovery of novel anti-angiogenesis agents with previously reported imidazole kinase inhibitors as a lead compound. A library of 29 compounds was synthesized. Several title compounds exhibited selective inhibitory activities against vascular endothelial growth factor receptor 2 (VEGFR-2) over epidermal growth factor receptor (EGFR) kinase; these compounds also displayed selective and potent antiproliferative activity against three cancer cell lines. The newly synthesized compounds were evaluated for anti-angiogenesis activity by chick chorioallantoic membrane (CAM) assay. Among them, 1-(2-(2-chlorophenyl)benzo[d]oxazol-5-yl)-3-(4-(trifluoromethoxy)phenyl)urea (compound 5 n) showed the most potent anti-angiogenesis capacity, efficient cytotoxic activities (in vitro against human umbilical vein endothelial cells (HUVEC), H1975, A549, and HeLa cell lines, with respective IC50 values of 8.46, 1.40, 7.61, and 0.28 µm), and an acceptable level of VEGFR-2 kinase inhibition (IC50 =0.25 µm). Molecular docking analysis revealed 5 n to be a type II inhibitor of VEGFR-2 kinase. In general, these results indicate that these 6-arylurea-2-arylbenzoxazole/benzimidazole derivatives are promising inhibitors of VEGFR-2 kinase for potential development into anti-angiogenesis drugs.


Assuntos
Inibidores da Angiogênese/síntese química , Benzimidazóis/química , Benzoxazóis/química , Desenho de Fármacos , Inibidores da Angiogênese/metabolismo , Inibidores da Angiogênese/farmacologia , Animais , Benzimidazóis/metabolismo , Benzimidazóis/farmacologia , Benzoxazóis/metabolismo , Benzoxazóis/farmacologia , Sítios de Ligação , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Galinhas , Humanos , Simulação de Acoplamento Molecular , Neovascularização Fisiológica/efeitos dos fármacos , Estrutura Terciária de Proteína , Relação Estrutura-Atividade , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo
11.
Environ Pollut ; 252(Pt A): 51-61, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31146238

RESUMO

Melatonin (Mel) serves as an important signalling molecule in various aspects of stress tolerance in plants. However, the function of Mel in pesticide metabolism remains unknown. Here, selecting the widely used fungicide carbendazim (MBC) as the model, we found that exogenous Mel had the ability to alleviate pesticide phytotoxicity and residues in tomato as well as in some other vegetables. Additionally, overexpression of the Mel biosynthetic gene caffeic acid O-methyltransferase 1 (COMT1) significantly enhanced the capacity of the tomato to reduce MBC phytotoxicity and residue. This outcome was mainly because of the Mel-induced antioxidant capability, as well as the key detoxification process. Indeed, levels of reactive oxygen species (ROS) and lipid peroxides significantly decreased after applying exogenous Mel or overexpressing COMT1, which resulted from direct ROS scavenging, and increased Mel levels significantly enhanced antioxidant enzymatic activity. More importantly, Mel activated the ascorbate-glutathione cycle to participate in glutathione S-transferase-mediated pesticide detoxification. A grafting experiment showed that rootstocks from COMT1 transgenic plants increased the Mel accumulation of wild-type scions, resulting in MBC metabolism in the scions. To our knowledge, this is the first report providing evidence of Mel-induced pesticide metabolism, which provides a novel approach for minimizing pesticide residues in crops by exploiting plant self-detoxification mechanisms.


Assuntos
Benzimidazóis/metabolismo , Carbamatos/metabolismo , Fungicidas Industriais/metabolismo , Inativação Metabólica/fisiologia , Lycopersicon esculentum/metabolismo , Melatonina/metabolismo , Metiltransferases/metabolismo , Benzimidazóis/toxicidade , Carbamatos/toxicidade , Fungicidas Industriais/toxicidade , Glutationa Transferase/metabolismo , Peróxidos Lipídicos/metabolismo , Melatonina/biossíntese , Metiltransferases/biossíntese , Plantas Geneticamente Modificadas/metabolismo , Espécies Reativas de Oxigênio/metabolismo
12.
Bioconjug Chem ; 30(5): 1371-1384, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30946570

RESUMO

Animal models are effective for assessing tumor localization of nanosystems but difficult to use for studying penetration beyond the vasculature. Here, we have used well-characterized HCT116 colorectal cancer spheroids to study the effect of nanoparticle (NP) physicochemical properties on penetration and uptake. Incubation of spheroids with Hoechst 33342 resulted in a dye gradient, which facilitated discrimination between the populations of cells in the core and at the periphery of spheroids by flow cytometry. This approach was used to compare doxorubicin and liposomal doxorubicin (Caelyx) and a range of model poly(styrene) nanoparticles of different sizes (30 nm, 50 nm, 100 nm) and with different surface chemistries (50 nm uniform plain, carboxylated, aminated and a range of NPs and polyethylene glycol modified NPs prepared from a promising new functionalized biodegradable polymer (poly(glycerol-adipate), PGA). Unmodified poly(styrene) nanoparticles (30 nm/50 nm) were able to penetrate to the core of HCT116 spheroids more efficiently than larger poly(styrene) nanoparticles (100 nm). Surprisingly, penetration of 30 and 50 nm particles was as good as clinically relevant doxorubicin concentrations. However, penetration was reduced with higher surface charge. PGA NPs of 100 nm showed similar penetration into spheroids as 50 nm poly(styrene) nanoparticles, which may be related to polymer flexibility. PEG surface modification of polymeric particles significantly improved penetration into the spheroid core. The new model combining the use of spheroids Hoechst staining and flow cytometry was a useful model for assessing NP penetration and gives useful insights into the effects of NPs' physical properties when designing nanomedicines.


Assuntos
Neoplasias Colorretais/metabolismo , Nanopartículas , Esferoides Celulares/metabolismo , Animais , Antibióticos Antineoplásicos/administração & dosagem , Antibióticos Antineoplásicos/farmacocinética , Benzimidazóis/metabolismo , Doxorrubicina/administração & dosagem , Doxorrubicina/análogos & derivados , Doxorrubicina/farmacocinética , Corantes Fluorescentes/metabolismo , Células HCT116 , Humanos , Tamanho da Partícula , Polietilenoglicóis/administração & dosagem , Polietilenoglicóis/farmacocinética , Propriedades de Superfície
13.
Bioorg Med Chem Lett ; 29(10): 1182-1186, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30926247

RESUMO

Previously disclosed benzimidazole-based DGAT1 inhibitors containing a cyclohexane carboxylic acid moiety suffer from isomerization at the alpha position of the carboxylic acid group, generating active metabolites which exhibit DGAT1 inhibition comparable to the corresponding parent compounds. In this report, we describe the design, synthesis and profiling of benzimidazole-based DGAT1 inhibitors with a [3.1.0] bicyclohexane carboxylic acid moiety. Our results show that single isomer 3A maintains in vitro and in vivo inhibition against DGAT1. In contrast to previous lead compounds, 3A does not undergo isomerization during in vitro hepatocyte incubation study or in vivo mouse study.


Assuntos
Benzimidazóis/química , Ácidos Carboxílicos/química , Diacilglicerol O-Aciltransferase/antagonistas & inibidores , Inibidores Enzimáticos/química , Animais , Benzimidazóis/metabolismo , Ácidos Carboxílicos/metabolismo , Cromatografia Líquida de Alta Pressão , Cicloexanonas/química , Diacilglicerol O-Aciltransferase/metabolismo , Inibidores Enzimáticos/análise , Inibidores Enzimáticos/metabolismo , Hepatócitos/química , Hepatócitos/metabolismo , Humanos , Concentração Inibidora 50 , Isomerismo , Espectrometria de Massas , Camundongos , Ratos
14.
Recent Pat Drug Deliv Formul ; 13(1): 62-69, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30848223

RESUMO

BACKGROUND: The present study reports the formation of a cocrystal of candesartan with the coformer methyl paraben, its characterization and determination of its bioavailability. Candesartan is a poorly water-soluble drug having an anti-hypertensive activity. The recent patents on the cocrystals of the drugs Progesterone (US9982007B2), Epalrestat (EP2326632B1), Gefitinib (WO2015170345A1), and Valsartan (CN102702118B) for enhancement of solubility, helped in selection of the drug for this work. METHODS: Candesartan cocrystal was prepared by solution crystallization method. The formation of a new crystalline phase was characterized by Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) and Powder X-ray Diffraction (PXRD) studies. Saturation solubility studies were carried out in ethanol: water (50:50 % v/v) mixture. The dissolution studies were conducted in 900 ml of phosphate buffer at pH 7.4(I.P.) with 0.7% w/w of Tween 20 at 50 rpm, maintained at a temperature of 37±0.5°C in a USP type II dissolution apparatus. The pharmacokinetic behavior of candesartan and its cocrystal was thereof investigated in male Wistar rats. RESULTS: There was 6.94 fold enhancement in the solubility of candesartan after its cocrystallization. The dissolution profile of the cocrystal exhibited significant improvement in solubility at 60 and 120 minutes and it remained stable in ethanol: water (50:50%v/v) mixture for 48 h as confirmed by PXRD studies. The AUC0-24of the cocrystal was found to be increased by 2.9 fold in terms of bioavailability as compared to the pure drug. CONCLUSION: The prepared cocrystal was found to be relatively more soluble than the pure drug and also showed an enhanced oral bioavailability as compared to the pure drug.


Assuntos
Benzimidazóis/química , Química Farmacêutica/métodos , Parabenos/química , Patentes como Assunto , Tetrazóis/química , Água/química , Animais , Benzimidazóis/metabolismo , Cristalização/métodos , Masculino , Parabenos/metabolismo , Ratos , Ratos Wistar , Solubilidade , Tetrazóis/metabolismo , Água/metabolismo , Difração de Raios X/métodos
15.
Microsc Res Tech ; 82(6): 892-897, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30767333

RESUMO

With the development of advanced and minimally invasive surgical techniques, and in view of the functional and cosmetic aspects, the need for rapid and accurate diagnosis during surgery is increasing. This study was conducted to develop a tissue diagnosis method using confocal microscopy after simple tissue staining that does not require freezing and slicing. At present, fluorescence staining with confocal microscopy is not generalized for real-time diagnosis during surgery. In this paper, we propose a fluorescence staining method using Hoechst 33342 and Eosin that does not require tissue freezing and slicing. The proposed method can be used as part of a rapid tissue diagnosis method that is suitable for use in the operating room, although further research is required before it can be applied in clinical practice.


Assuntos
Histocitoquímica/métodos , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Manejo de Espécimes/métodos , Coloração e Rotulagem/métodos , Benzimidazóis/metabolismo , Amarelo de Eosina-(YS)/metabolismo , Humanos , Fatores de Tempo
16.
Food Chem ; 284: 279-286, 2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-30744858

RESUMO

Benzimidazoles (BZDs) are widely used veterinary drugs in the domestic food-producing animals, resulting in the metabolism of BZDs and the harmful metabolites residues in some foods. However, some BZD metabolites are unknown and so it is important to discover new metabolites to expand detection targets. For these reasons, a sensitive and selective strategy was designed to identify BZD metabolites in the serum of pigs after oral administration of albendazole, fenbendazole and thiabendazole, respectively. Nickel oxide nanoparticle-deposited silica (SiO2@NiO) composite was used for the enrichment and purification of BZD compounds. High-performance liquid chromatography coupled with precursor ion scan-mass spectrometry (LC-PIS-MS) and high resolution MS/MS analysis (HR-MS/MS) was employed for the BZDs metabolic profiles characterization and metabolites detection. Finally, 18 BZD metabolites were identified, among which 11 metabolites were discovered in pig serum for the first time. Besides, more comprehensive BZD metabolic pathways were presented.


Assuntos
Benzimidazóis/sangue , Nanopartículas Metálicas/química , Dióxido de Silício/química , Espectrometria de Massas em Tandem/métodos , Animais , Benzimidazóis/isolamento & purificação , Benzimidazóis/metabolismo , Cromatografia Líquida de Alta Pressão , Níquel/química , Extração em Fase Sólida , Suínos
17.
ACS Chem Biol ; 14(3): 325-331, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30735352

RESUMO

Activating mutations in RAS can lead to oncogenesis by enhancing downstream signaling, such as through the MAPK and PI3K pathways. Therefore, therapeutically targeting RAS may perturb multiple signaling pathways simultaneously. One method for modulating RAS signaling is to target the activity of the guanine nucleotide exchange factor SOS1. Our laboratory has discovered compounds that bind to SOS1 and activate RAS. Interestingly, these SOS1 agonist compounds elicit biphasic modulation of ERK phosphorylation and simultaneous inhibition of AKT phosphorylation levels. Here, we utilized multiple chemically distinct compounds to elucidate whether these effects on MAPK and PI3K signaling by SOS1 agonists were mechanistically linked. In addition, we used CRISPR/Cas9 gene-editing to generate clonally derived SOS1 knockout cells and identified a potent SOS1 agonist that rapidly elicited on-target molecular effects at substantially lower concentrations than those causing off-target effects. Our findings will allow us to further define the on-target utility of SOS1 agonists.


Assuntos
Benzimidazóis/química , Indóis/química , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Quinazolinas/química , Proteína SOS1/agonistas , Benzimidazóis/metabolismo , Proteína 9 Associada à CRISPR/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Edição de Genes , Humanos , Indóis/metabolismo , Quinazolinas/metabolismo
18.
ACS Appl Mater Interfaces ; 11(5): 4766-4776, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30644707

RESUMO

Synthetic organic molecules, which can selectively convert excess intracellular copper (Cu) ions to nanozymes with an ability to protect cells from oxidative stress, are highly significant in developing therapeutic agents against Cu-related disorder like Wilson's disease. Here, we report 1,3-bis(2-hydroxyethyl)-1 H-benzoimidazole-2-selenone (1), which shows a remarkable ability to remove Cu ion from glutathione, a major cytosolic Cu-binding ligand, and thereafter converts it into copper selenide (CuSe) nanozyme that exhibits remarkable glutathione peroxidase-like activity, at cellular level of H2O2 concentration, with excellent cytoprotective effect against oxidative stress in hepatocyte. Cu-driven deselenization of 1, under physiologically relevant conditions, occurred in two steps. The activation of C═Se bond by metal ion is the crucial first step, followed by cleavage of the metal-activated C═Se bond, initiated by the OH group of N-(CH2)2OH substituent through neighboring group participation (deselenization step), resulted in the controlled synthesis of various types of Cu2-xSe nanocrystals (NCs) (nanodisks, nanocubes, and nanosheets) and tetragonal Cu3Se2 NCs, depending upon the oxidation state of the Cu ion used to activate the C═Se bond. Deselenization of 1 is highly metal-selective. Except Cu, other essential metal ions, including Mn2+, Fe2+, Co2+, Ni2+, or Zn2+, failed to produce metal selenide under identical reaction conditions. Moreover, no significant change in the expression level of Cu-metabolism-related genes, including metallothioneines MT1A, is observed in liver cells co-treated with Cu and 1, as opposed to the large increase in the concentrations of these genes observed in cells treated with Cu alone, suggesting the participation of 1 in Cu homeostasis in hepatocyte.


Assuntos
Antioxidantes , Benzimidazóis , Cobre , Nanopartículas , Compostos de Selênio , Antioxidantes/química , Antioxidantes/metabolismo , Benzimidazóis/química , Benzimidazóis/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Cobre/análise , Cobre/metabolismo , Glutationa Peroxidase/química , Glutationa Peroxidase/metabolismo , Células Hep G2 , Humanos , Peróxido de Hidrogênio/toxicidade , Nanopartículas/química , Nanopartículas/metabolismo , Compostos Organosselênicos/química , Compostos Organosselênicos/metabolismo , Estresse Oxidativo , Compostos de Selênio/análise , Compostos de Selênio/metabolismo
19.
Biochemistry ; 58(6): 809-817, 2019 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-30628776

RESUMO

DNA topoisomerases are unique enzymes that alter the topology of DNA by cleavage and religation mechanisms. Small molecules such as camptothecins and noncamptothecins are reported to inhibit different classes of topoisomerases. Benzimidazole, 2-(3,4-dimethoxyphenyl)-5-[5-(4-methylpiperazin-1-yl)-1 H-benzimidazol-2-yl]-1 H benzimidazole (DMA), a new analogue of Hoechst 33342, was observed as a selective and differential inhibitor of human and Escherichia coli DNA topoisomerase I. In this study, we have concluded that DMA and Hoechst 33342 have differential binding toward human and E. coli topoisomerase I. We also dissected the mechanism of differential binding, as DMA and Hoechst 33342 bind to human topoisomerase I with linear kinetics with reversible binding, whereas the same molecules bind to E. coli topoisomerase I in a nonlinear and irreversible manner, which contributes to higher affinity and comparatively good IC50 values toward E. coli topoisomerase I. Interestingly, DMA and Hoechst 33342 showed inhibition of mutant human topoisomerases I, i.e., A653P, N722S, and T729P, whereas these clinically relevant mutants are resistant to camptothecins.


Assuntos
Benzimidazóis/metabolismo , DNA Topoisomerases Tipo I/metabolismo , DNA/metabolismo , Proteínas de Escherichia coli/metabolismo , Piperazinas/metabolismo , Inibidores da Topoisomerase I/metabolismo , Benzimidazóis/química , Camptotecina/química , Domínio Catalítico , DNA Topoisomerases Tipo I/química , DNA Topoisomerases Tipo I/genética , Escherichia coli/enzimologia , Proteínas de Escherichia coli/química , Humanos , Simulação de Acoplamento Molecular , Mutação , Piperazinas/química , Plasmídeos/metabolismo , Ligação Proteica
20.
Phys Chem Chem Phys ; 21(4): 1841-1851, 2019 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-30629058

RESUMO

Regulation of gene-expression by specific targeting of protein-nucleic acid interactions has been a long-standing goal in medicinal chemistry. Transcription factors are considered "undruggable" because they lack binding sites well suited for binding small-molecules. In order to overcome this obstacle, we are interested in designing small molecules that bind to the corresponding promoter sequences and either prevent or modulate transcription factor association via an allosteric mechanism. To achieve this, we must design small molecules that are both sequence-specific and able to target G/C base pair sites. A thorough understanding of the relationship between binding affinity and the structural aspects of the small molecule-DNA complex would greatly aid in rational design of such compounds. Here we present a comprehensive analysis of sequence-specific DNA association of a synthetic minor groove binder using long timescale molecular dynamics. We show how binding selectivity arises from a combination of structural factors. Our results provide a framework for the rational design and optimization of synthetic small molecules in order to improve site-specific targeting of DNA for therapeutic uses in the design of selective DNA binders targeting transcription regulation.


Assuntos
DNA , Benzamidinas/química , Benzamidinas/metabolismo , Benzimidazóis/química , Benzimidazóis/metabolismo , Sítios de Ligação , DNA/química , DNA/metabolismo , Substâncias Intercalantes/química , Substâncias Intercalantes/metabolismo , Simulação de Dinâmica Molecular , Conformação de Ácido Nucleico , Bibliotecas de Moléculas Pequenas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA