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1.
Chem Commun (Camb) ; 56(10): 1557-1560, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31930253

RESUMO

A difunctionalization of alkenes through sequential addition of a radical and a nucleophile has been developed, which is suggested to proceed by a radical chain mechanism not requiring a catalyst. An electron transfer step to the oxidant benzoyl peroxide is facilitated by protonation with a strong acid.


Assuntos
Alcenos/química , Estirenos/química , Peróxido de Benzoíla/química , Técnicas Eletroquímicas , Transporte de Elétrons , Nitrogênio/química , Oxirredução , Oxigênio/química
2.
Phytochemistry ; 171: 112248, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31918304

RESUMO

The phytochemical investigation of the twig and leaf extracts of Goniothalamus tamirensis led to the isolation and identification of 15 compounds including three rare previously undescribed styryllactones, goniotamirenones A-C, together with 12 known compounds. (Z)-6-Styryl-5,6-dihydro-2-pyranone and 5-(1-hydroxy-3-phenyl-allyl)-dihydro-furan-2-one are reported here for the first time as previously undescribed natural products. Their structures were elucidated by spectroscopic methods. Goniotamirenone A was synthesized via a [2 + 2] cycloaddition reaction of 6-styrrylpyran-2-one in quantitative yield. The absolute configurations of goniotamirenones B and C were identified from experimental and calculated ECD data, while the absolute configurations of (-)-5-acetoxygoniothalamin, (-)-isoaltholactone, parvistone E, and 5-(1-hydroxy-3-phenyl-allyl)-dihydro-furan-2-one were identified by single-crystal X-ray diffraction analysis using Cu Kα radiation. The absolute configurations of the other related compounds were determined from comparisons of their ECD spectra with relevant compounds reported in the literature. (-)-5-Acetoxygoniothalamin exhibited potent cytotoxicity against the colon cancer cell line (HCT116) with an IC50 value of 8.6 µM which was better than the standard control (doxorubicin, IC50 = 9.7 µM), while (Z)-6-styryl-5,6-dihydro-2-pyranone was less active with an IC50 value of 22.1 µM.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Goniothalamus/química , Lactonas/farmacologia , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/farmacologia , Estirenos/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Teoria da Densidade Funcional , Ensaios de Seleção de Medicamentos Antitumorais , Células HCT116 , Humanos , Lactonas/química , Lactonas/isolamento & purificação , Modelos Moleculares , Estrutura Molecular , Compostos Fitoquímicos/química , Compostos Fitoquímicos/isolamento & purificação , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Estirenos/química , Estirenos/isolamento & purificação
3.
Talanta ; 206: 120245, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514823

RESUMO

A novel L-tryptophan (L-Trp) electrochemical sensor is fabricated, which is based on the molecularly imprinted copolymer (MIP) of dual -functional monomers and ionic liquid (i.e. 1-butyl-3-methylimidazolium hexafluorophosphate) functionalized multi-walled carbon nanotubes (MWCNTs@IL). The MWCNTs@IL is prepared via ion exchange, while the MIP is synthesized by using L-Trp as template, styrene and 4-vinylbenzoic acid as functional monomers, Triton X-100 as emulsifier, 1, 2-divinylbenzene as cross-linking reagent and K2S2O8 as initiator. Prior to copolymerization the functional monomer 4-vinylbenzoic acid is combined with the template molecule by forming amide bond. The template molecule is eluted by hydrolysis, and rebound by electrostatic, hydrogen-bond and π-π interaction. To construct L-Trp sensor a little of Nafion is introduced to enhance the stability and to promote rebinding. The resulting sensor Nafion-MIP-MWCNTs@IL/GCE shows a wide linear range (8 nM-26 µM) and a low detection limit (6 nM). It is successfully applied to the determination of L-Trp in oral liquid and human serum samples.


Assuntos
Técnicas Eletroquímicas/métodos , Polímeros/química , Triptofano/sangue , Técnicas Eletroquímicas/instrumentação , Eletrodos , Polímeros de Fluorcarboneto/química , História Medieval , Humanos , Imidazóis/química , Limite de Detecção , Impressão Molecular/métodos , Nanotubos de Carbono/química , Polimerização , Polímeros/síntese química , Reprodutibilidade dos Testes , Estereoisomerismo , Estireno/química , Estirenos/química , Triptofano/química
4.
Org Biomol Chem ; 17(45): 9712-9725, 2019 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-31531484

RESUMO

Fluorescent hybridization probes are important tools for rapid, specific and sensitive analysis of genetic mutations. In this work, we synthesized novel alkyne-modified styryl dyes for conjugation with pyrrolidinyl peptide nucleic acid (acpcPNA) by click chemistry for the development of hybridization responsive fluorescent PNA probes. The free styryl dyes generally exhibited weak fluorescence in aqueous media, and the fluorescence was significantly enhanced (up to 125-fold) upon binding with DNA duplexes. Selected styryl dyes that showed good responses with DNA were conjugated with PNA via sequential reductive alkylation-click chemistry. Although these probes showed little fluorescence change when hybridized to complementary DNA, significant fluorescence enhancements were observed in the presence of structural defects including mismatched, abasic and base-inserted DNA targets. The largest increase in fluorescence quantum yield (up to 14.5-fold) was achieved with DNA carrying base insertion. Although a number of probes were designed to give fluorescence response to complementary DNA targets, probes that are responsive to mutations such as single nucleotide polymorphism (SNP), base insertion/deletion and abasic site are less common. Therefore, styryl-dye-labeled acpcPNA is a unique probe that is responsive to structural defects in the duplexes that may be further applied for diagnostic purposes.


Assuntos
Sondas de DNA/química , DNA/análise , Fluorescência , Corantes Fluorescentes/química , Ácidos Nucleicos Peptídicos/química , Pirrolidinas/química , Estirenos/química , Química Click , DNA/genética , Corantes Fluorescentes/síntese química , Estrutura Molecular , Mutação , Estirenos/síntese química
5.
Comput Biol Chem ; 83: 107112, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31480006

RESUMO

Prostate cancer is a common cause of death in men and a novel treating methods should be developed. In order to find a new drug for prostate cancer, a series of novel conformationally constrained analogues of (+)-goniofufurone and 7-epi-(+)-goniofufurone, as well as the newly synthesized styryl lactones containing the cinnamic acid ester groups were evaluated for in vitro cytotoxicity against prostate cancer cell (PC-3). Furthermore, prediction of physicochemical characteristics and drugability as well as in silico ADME-Tox tests of investigated compounds were performed. The 3D-QSAR model was established using the comparative molecular field analysis method. According to obtained results, the tricyclic compounds 9 and 10 had the highest potency with IC50 < 20 µM. Evaluation of structural features through 3D-QSAR model identified steric field feature on the cinnamic acid ester groups at C-7 as a crucial for the cytotoxic activity. This research suggests that most of the analysed compounds have desirable properties for drug candidates and high potential in drug development, which recommend them for further research in treatment of prostate cancer. Furthermore, obtained 3D-QSAR model is able to successfully identify styryl lactones that have significant cytotoxic activity and provide information for screening and design of novel inhibitors against PC-3 cell line that could be used as drugs in treatment of the prostate cancer.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Produtos Biológicos/farmacologia , Lactonas/farmacologia , Relação Quantitativa Estrutura-Atividade , Estirenos/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/metabolismo , Produtos Biológicos/química , Produtos Biológicos/metabolismo , Proliferação de Células/efeitos dos fármacos , Simulação por Computador , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Lactonas/química , Lactonas/metabolismo , Modelos Moleculares , Células PC-3 , Estirenos/química , Estirenos/metabolismo
6.
J Agric Food Chem ; 67(41): 11354-11363, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31532666

RESUMO

A series of dehydrozingerone derivatives were synthesized, and their fungicidal activities and action mechanism against Colletotrichum musae were evaluated. The bioassay result showed that most compounds exhibited excellent fungicidal activity in vitro at 50 µg mL-1. Compounds 13, 16, 18, 19, and 27 exhibited broad-spectrum fungicidal activity; especially, compounds 19 and 27 were found to have more potent fungicidal activity than azoxystrobin. The EC50 values of compounds 19 and 27 against Rhizoctonia solani were 0.943 and 0.161 µg mL-1 respectively. Moreover, compound 27 exhibited significant in vitro bactericidal activity against Xanthomonas oryzae pv. oryzae, with an EC50 value of 11.386 µg mL-1, and its curative effect (49.64%) and protection effect (51.74%) on rice bacterial blight disease was equivalent to that of zhongshengmycin (42.90%, 40.80% respectively). Compound 27 could also effectively control gray mold (87.10%, 200 µg mL-1) and rice sheath blight (100%, 200 µg mL-1; 82.89%, 100 µg mL-1) in vivo. Preliminary action mechanism study showed that compound 27 mainly acted on the cell membrane and significantly inhibited ergosterol biosynthesis in Colletotrichum musae.


Assuntos
Ergosterol/antagonistas & inibidores , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Estirenos/síntese química , Estirenos/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Colletotrichum/efeitos dos fármacos , Colletotrichum/metabolismo , Ergosterol/biossíntese , Fungicidas Industriais/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Oryza/microbiologia , Doenças das Plantas/microbiologia , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/metabolismo , Relação Estrutura-Atividade , Estirenos/química , Xanthomonas/efeitos dos fármacos , Xanthomonas/metabolismo
7.
Anal Chim Acta ; 1080: 153-161, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31409465

RESUMO

A red-emitting and ratiometric fluorescence probe 1 for detecting H2O2, based on a styrylnaphthalimide-boronate ester was developed. Upon a H2O2-mediated hydrolysis of boronate ester, probe 1 was transformed to 2 with a ratiometric fluorescence change, decrease at 535 and increase at 640 nm. It was also found that the fluorescent reaction of 1 with H2O2 in solution could be completed within 10 min and the detection limit was estimated to be 0.30 µM. Moreover, this ratiometric change was highly selective for H2O2 over other redox species, metal ions, and anions. Also, this system was found to be capable of detecting H2O2 in the pH range of 6-9. Furthermore, probe 1 was preferentially accumulated into the endoplasmic reticulum (ER) in the live HeLa cells, and an increased H2O2 level in the presence of an ER stress inducer, thapsigargin was revealed.


Assuntos
Ácidos Borônicos/química , Corantes Fluorescentes/química , Peróxido de Hidrogênio/análise , Naftalimidas/química , Estirenos/química , Ácidos Borônicos/síntese química , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Corantes Fluorescentes/síntese química , Células HeLa , Humanos , Limite de Detecção , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Naftalimidas/síntese química , Estirenos/síntese química , Tapsigargina/farmacologia
8.
Molecules ; 24(14)2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31295835

RESUMO

We investigated the selective oxidation of styrenes to benzaldehydes by using a non-irradiated TiO2-H2O2 catalytic system. The oxidation promotes multi-step reactions from styrenes, including the cleavage of a C=C double bond and the addition of an oxygen atom selectively and stepwise to provide the corresponding benzaldehydes in good yields (up to 72%). These reaction processes were spectroscopically shown by fluorescent measurements under the presence of competitive scavengers. The absence of the signal from OH radicals indicates the participation of other oxidants such as hydroperoxy radicals (•OOH) and superoxide radicals (•O2-) into the selective oxidation from styrene to benzaldehyde.


Assuntos
Aldeídos/química , Peróxido de Hidrogênio/química , Oxirredução , Estirenos/química , Temperatura Ambiente , Titânio/química , Catálise , Modelos Químicos , Estrutura Molecular
9.
Eur J Med Chem ; 177: 338-349, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158748

RESUMO

A series of styrylquinolines was designed and synthesized based on the four main quinoline scaffolds including oxine, chloroxine and quinolines substituted with a hydroxyl group or chlorine atom at the C4 position. All of the compounds were tested for their anticancer activity on wild-type colon cancer cells (HCT 116) and those with a p53 deletion. Analysis of SAR revealed the importance of electron-withdrawing substituents in the styryl part and chelating properties in the quinoline ring. The compounds that were more active were also tested on a panel of four cancer cell lines with mutations in TP53 tumor suppressor gene. The results suggest that styrylquinolines induce cell cycle arrest and activate a p53-independent apoptosis. The apparent mechanism of action was studied for the most promising compounds, which produced reactive oxygen species and changed the cellular redox balance.


Assuntos
Antineoplásicos/farmacologia , Quinolinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Estirenos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/toxicidade , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Heme Oxigenase-1/metabolismo , Humanos , Estrutura Molecular , Poli(ADP-Ribose) Polimerase-1/metabolismo , Quinolinas/síntese química , Quinolinas/química , Quinolinas/toxicidade , Pontos de Checagem da Fase S do Ciclo Celular/efeitos dos fármacos , Relação Estrutura-Atividade , Estirenos/síntese química , Estirenos/química , Estirenos/toxicidade , Proteína Supressora de Tumor p53/metabolismo
10.
Org Biomol Chem ; 17(16): 3934-3939, 2019 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-30942247

RESUMO

The mechanism of the enantioselective Michael addition of diethyl malonate to trans-ß-nitrostyrene catalyzed by a tertiary amine thiourea organocatalyst is explored using experimental 13C kinetic isotope effects and density functional theory calculations. Large primary 13C KIEs on the bond-forming carbon atoms of both reactants suggest that carbon-carbon bond formation is the rate-determining step in the catalytic cycle. This work resolves conflicting mechanistic pictures that have emerged from prior experimental and computational studies.


Assuntos
Tioureia/química , Catálise , Teoria da Densidade Funcional , Malonatos/química , Estrutura Molecular , Estereoisomerismo , Estirenos/síntese química , Estirenos/química
11.
Nat Chem ; 11(6): 578-586, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30988414

RESUMO

Polymerization reactions conducted inside cells must be compatible with the complex intracellular environment, which contains numerous molecules and functional groups that could potentially prevent or quench polymerization reactions. Here we report a strategy for directly synthesizing unnatural polymers in cells through free radical photopolymerization using a number of biocompatible acrylic and methacrylic monomers. This offers a platform to manipulate, track and control cellular behaviour by the in cellulo generation of macromolecules that have the ability to alter cellular motility, label cells by the generation of fluorescent polymers for long-term tracking studies, as well as generate a variety of nanostructures within cells. It is remarkable that free radical polymerization chemistry can take place within such complex cellular environments. This demonstration opens up a multitude of new possibilities for how chemists can modulate cellular function and behaviour and for understanding cellular behaviour in response to the generation of free radicals.


Assuntos
Radicais Livres/química , Polimerização/efeitos da radiação , Ácidos Polimetacrílicos/síntese química , Poliestirenos/síntese química , Acrilatos/química , Acrilatos/efeitos da radiação , Acrilatos/toxicidade , Citoesqueleto de Actina/efeitos dos fármacos , Compostos de Anilina/química , Compostos de Anilina/efeitos da radiação , Compostos de Anilina/toxicidade , Movimento Celular/efeitos dos fármacos , Fluorescência , Células HeLa , Humanos , Metacrilatos/química , Metacrilatos/efeitos da radiação , Metacrilatos/toxicidade , Propano/análogos & derivados , Propano/química , Propano/efeitos da radiação , Fase S/efeitos dos fármacos , Estirenos/química , Estirenos/efeitos da radiação , Estirenos/toxicidade , Raios Ultravioleta , Compostos de Vinila/química , Compostos de Vinila/efeitos da radiação , Compostos de Vinila/toxicidade
12.
Phytochemistry ; 161: 107-116, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30825705

RESUMO

Styrene analogs are known to be naturally synthesized in the leaves of pears and in other plant species, including several trees in the Styracaceae family. Styrene analogs are potential contributors to the aroma of wine, perfumes, pharmaceuticals, and other fermented foods and beverages. In addition, styrene analogs perform important ecological functions such as insecticidal and antifeedant activities against insects. We showed here that exogenous applications of styrene and p-hydroxystyrene caused a dramatic reduction the number of eggs laid by psylla and of subsequent nymph survival. Despite their importance specific reactions that lead to the biosynthesis of the styrene analogs in pear are unknown. To identify genes involved in the synthesis of these metabolites, existing genome databases of the Rosaceae were screened for pear genes with significant sequence similarity to bacterial phenolic acid decarboxylase. Herein described are the isolation and characterization of a pear phenolic acid decarboxylase, designated PyPAD1, which catalyzed the decarboxylation of p-coumaric acid and ferulic acid to p-hydroxystyrene and 3-methoxy-4-hydroxystyrene respectively. Its apparent Km values for p-coumaric acid and ferulic acid were 34.42 and 84.64 µM, respectively. The PyPAD1 preferred p-coumaric acid to ferulic acid as a substrate by a factor of 2.4 when comparing catalytic efficiencies in vitro. Expression analysis of PyPAD1 showed that the gene was transcribed in all five pear genotypes examined. However, transcript abundance was increased in correlation with the presence of p-hydroxystyrene in resistant cultivars Py-701 and Py-760 and in the sensitive cultivar Spadona when grafted on these resistant cultivars. Thus, PyPAD1 appears to be responsible for the decarboxylation of the p-coumaric acid, and for the production of metabolites that are active against pear psylla.


Assuntos
Bidens/efeitos dos fármacos , Hemípteros/efeitos dos fármacos , Inseticidas/farmacologia , Pyrus/metabolismo , Estirenos/farmacologia , Animais , Bidens/metabolismo , Hemípteros/metabolismo , Inseticidas/química , Inseticidas/metabolismo , Pyrus/genética , Estirenos/química , Estirenos/metabolismo
13.
Oncol Rep ; 41(5): 3127-3136, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30896840

RESUMO

The nitrostyrene scaffold was previously identified as a lead target structure for the development of effective compounds targeting Burkitt's lymphoma. The present study aimed to develop these compounds further in haematological malignancies, including chronic lymphocytic leukaemia (CLL). Cellular viability, flow cytometry and lactate dehydrogenase assays, amongst others, were used to examine the effects of nitrostyrene compounds on CLL cells, including a cell line representing disease with poor prognosis (HG­3) and in ex vivo CLL patient samples (n=14). The results demonstrated that two representative nitrostyrene compounds potently induced apoptosis in CLL cells. The pro­apoptotic effects of the compounds were found to be reactive oxygen species and caspase­dependent, and had minimal effects on the viability of normal donor peripheral blood mononuclear cells. Nitrostyrene compounds exhibited synergistic augmentation of apoptosis when combined with the phosphatidylinositol 3­kinase inhibitor idelalisib and demonstrated potent toxicity in ex vivo CLL cells, including those co­cultured with bone marrow stromal cells, making them more resistant to apoptosis (n=8). These compounds also demonstrated activity in samples from patients with poor prognostic indicators; unmutated immunoglobulin heavy chain genes, expression of CD38 and deletions in chromosomes 17p and 11q. These results suggest that this class of pharmaceutically active compounds offer potential in the treatment of CLL.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Nitrocompostos/farmacologia , Estirenos/farmacologia , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/química , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Apoptose/efeitos dos fármacos , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Sinergismo Farmacológico , Feminino , Humanos , Concentração Inibidora 50 , Leucemia Linfocítica Crônica de Células B/sangue , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/mortalidade , Leucócitos Mononucleares , Masculino , Pessoa de Meia-Idade , Nitrocompostos/química , Nitrocompostos/uso terapêutico , Cultura Primária de Células , Prognóstico , Purinas/farmacologia , Purinas/uso terapêutico , Quinazolinonas/farmacologia , Quinazolinonas/uso terapêutico , Relação Estrutura-Atividade , Estirenos/química , Estirenos/uso terapêutico
14.
Macromol Rapid Commun ; 40(11): e1900048, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30900788

RESUMO

The controlled syndiospecific polymerization of three Si-H-containing styrenes, that is, 4-(methylhydrosilyl)styrene (FSt-1), 4-(dimethylhydrosilyl)styrene (FSt-2) and 4-(diisopropylhydrosilyl)styrene (FSt-3), is realized in the presence of (C5 Me4 SiMe3 )Sc (CH2 C6 H5 )2 (THF)/[Ph3 C][B(C6 F5 )4 ]. Then a series of FSt-b-styrene-b-FSt triblock copolymers (FSt-St-FSt) are synthesized facilely via a sequential monomer feeding process (FSt-2, styrene, and FSt-2, respectively) during the polymerization. The syndiotactic polystyrene (sPS) block in the middle endows the copolymer with high melting point above 250 °C, whereas the Si-H groups on monomer FSt-2 introduce functional pendants to the end-blocks (with Si-H content of 31-63 mol%). Finally by a mild and high-effective hydrosilylation reaction, novel polar-group functionalized sPS is obtained.


Assuntos
Polímeros/química , Estirenos/química , Polimerização , Poliestirenos/química
15.
Food Chem ; 286: 136-140, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30827586

RESUMO

Curcumin is a phenolic compound produced by some plants, among which Curcuma longa is the reachest in this principal curcuminoid. At elevated temperature curcumin degrades to trans-6-(4'-hydroxy-3'-methoxyphenyl)-2,4-dioxo-5-hexenal, vanillin, ferulic acid and feruloylmethane, however, the formation of feruloyloacetone ((5E)-6-(4-hydroxy-3-methoxyphenyl)hex-5-ene-2,4-dione) in the curcumin degradation process has not been reported yet. As results from experiments, even 28.8% or 20.6% of the degraded curcumin is transformed to feruloyloacetone during 2 h heating of alkaline or acidic curcumin solution, respectively. The structure of the identified feruloyloacetone was confirmed by MSn, HRMS and NMR data. The presented results are important for food processing as feruloyloacetone is formed during food products preparation and its biological activity has not been fully recognized.


Assuntos
Curcumina/química , Estirenos/química , Benzaldeídos/química , Ácidos Cumáricos/química , Manipulação de Alimentos , Espectroscopia de Ressonância Magnética
16.
Anal Bioanal Chem ; 411(10): 2239-2248, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30790019

RESUMO

In this work, a novel Fe3O4@Cu3(btc)2-embedded polymerized high internal phase emulsion (Fe3O4@HKUST-1-polyHIPE) monolithic cake was synthesized, characterized and used as an adsorbent in the magnetic stir cake sorptive extraction (MSCSE) and determination of tetracycline antibiotics (TCs) in food samples by a combination of with high-performance liquid chromatography-fluorescence detection (HPLC-FLD). The prepared Fe3O4@HKUST-1-polyHIPE monolithic composites displayed a strong extraction ability and high column capacity due to enhanced interactions such as π-π interactions, hydrogen bonding, and electrostatic interactions. The extraction and desorption conditions were evaluated, and the calibration curves of four spiked TCs were linear (R2 ≥ 0.9991) in the range from 20 to 800 ng mL-1 for milk and egg samples, and 20 to 800 ng g-1 for chicken muscle and kidney samples. The limits of detection and the limits of quantification of the four TCs by using the proposed MSCSE-HPLC-FLD method were in the range of 1.9-4.6 and 5.5-13.9 ng mL-1 for milk and egg samples, and 1.8-3.7 and 5.3-13.0 ng g-1 for chicken muscle and kidney samples, respectively. The recoveries of the target TCs from spiked food samples were in the range from 86.6 to 110.7% with relative standard deviations lower than 7.0%. The proposed method was successfully applied for the determination of these four TCs in milk, egg, chicken muscle, and kidney samples.


Assuntos
Antibacterianos/análise , Fracionamento Químico/métodos , Cromatografia Líquida de Alta Pressão/métodos , Análise de Alimentos/métodos , Estruturas Metalorgânicas/química , Polímeros/química , Estirenos/química , Tetraciclinas/análise , Adsorção , Animais , Galinhas , Ovos/análise , Emulsões/química , Contaminação de Alimentos/análise , Limite de Detecção , Magnetismo/métodos , Carne/análise , Leite/química
17.
Chem Asian J ; 14(7): 952-957, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30779325

RESUMO

Here we report fluorescence turn-on synthetic lipid rafts by self-assembly of a cationic distyrylanthracene derivative on a negatively-charged sheet in an aqueous solution. First, the negatively-charged 2D membrane structure is formed by lateral associations of aromatic rods with carboxylate groups. Then, the synthetic rafts are floated on the surface of the negatively-charged sheets through electrostatic interactions. The fluorescence of the synthetic rafts is turned on due to the aggregation of the positively-charged AIE dye on the sheets, facilitating monitoring of the formation of rafts. Concanavalin A (Con A) protein can load hierarchically onto the synthetic rafts at neutral pH to provide discrete Con A aggregates with a uniform size of ≈12 nm. The uniform aggregates of Con A on the synthetic rafts can stimulate Jurkat cells with enhanced efficiency, as compared with random-sized aggregates of Con A.


Assuntos
Antracenos/química , Concanavalina A/química , Substâncias Macromoleculares/química , Microdomínios da Membrana/química , Compostos de Amônio Quaternário/química , Estirenos/química , Fluorescência , Humanos , Células Jurkat , Multimerização Proteica/efeitos dos fármacos , Eletricidade Estática
18.
Bioorg Med Chem ; 27(3): 552-559, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30611633

RESUMO

Selective and sensitive detection of G-quadruplex DNA structures is an important issue and attracts extensive interest. To this end, numerous small molecular fluorescent probes have been designed. Here, we present a series of N-alkylated styrylquinolinium dyes named Ls-1, Ls-2 and Ls-3 with varying side groups at the chain end. We found that these dyes exhibited different binding behaviors to DNAs, and Ls-2 with a sulfonato group at the chain end displayed sensitivity and selectivity to G-quadruplex DNA structures in vitro. The characteristics of this dye and its interaction with G-quadruplex DNA were comprehensively investigated by means of UV-vis spectrophotometry, fluorescence, circular dichroism and molecular docking. Furthermore, confocal fluorescence images and MTT assays indicated dye Ls-2 could pass through membrane and enter the living HepG2 cells with low cytotoxicity.


Assuntos
DNA/análise , Corantes Fluorescentes/química , Compostos de Quinolínio/química , Estirenos/química , Alquilação , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/farmacologia , Quadruplex G , Células Hep G2 , Humanos , Estrutura Molecular , Imagem Óptica , Compostos de Quinolínio/síntese química , Compostos de Quinolínio/farmacologia , Relação Estrutura-Atividade , Estirenos/síntese química , Estirenos/farmacologia
19.
Bull Environ Contam Toxicol ; 102(2): 297-302, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30443656

RESUMO

Preconcentration of Cd(II) and Pb(II) was carried out by using column solid phase extraction method. Amberlyst 15 was used as solid phase for these analytes. The optimum extraction conditions such as pH (4), type and volume of eluent (5 mL of 2 mol L-1 HNO3) sample flow rate (1 mL min-1) and sample volume (100 mL for Cd(II) and 750 mL for Pb(II)) were determined. The recoveries were found for Cd(II) and Pb(II) as 104% ± 1% and 102 % ± 2%, respectively. The limit of detections were found as 0.23 µg L-1 for Cd(II) and 0.13 µg L-1 for Pb(II). The effects of foreign ions were also studied. The method was validated by analyzing standard reference material and spiked water samples. Percent relative error and relative standard deviation were below 3% and 4%, respectively.


Assuntos
Cádmio/análise , Chumbo/análise , Extração em Fase Sólida/métodos , Espectrofotometria Atômica/métodos , Estirenos/química , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio , Limite de Detecção , Reprodutibilidade dos Testes
20.
Bioorg Chem ; 83: 438-449, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30448722

RESUMO

A moderate elevation in reactive oxygen species (ROS) levels can generally be controlled in normal cells, but may lead to death of cancer cells as the ROS level in cancer cells is already elevated. Therefore, a ROS-generating compound can act as a selective chemotherapeutic agent for cancer cells that does not affect normal cells. In our previous study, a compound containing a Michael acceptor was selectively cytotoxic to cancer cells without affecting normal cells; therefore, we designed and synthesized 26 compounds containing a Michael acceptor. Their cytotoxicities against HCT116 human colon cancer cell lines were measured by using a clonogenic long-term survival assay. To derive the structural conditions required to obtain stronger cytotoxicity against cancer cells, the relationships between the half-maximal cell growth inhibitory concentration values of the synthesized compounds and their physicochemical properties were evaluated by Comparative Molecular Field Analysis and Comparative Molecular Similarity Indices Analysis. It was confirmed that the compound with the best half-maximal cell growth inhibitory concentration triggered apoptosis through ROS generation, which then led to stimulation of the caspase pathway.


Assuntos
Antineoplásicos/farmacologia , Chalconas/farmacologia , Estirenos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Chalconas/síntese química , Chalconas/química , Células HCT116 , Humanos , Modelos Moleculares , Estrutura Molecular , Relação Quantitativa Estrutura-Atividade , Espécies Reativas de Oxigênio/metabolismo , Estirenos/síntese química , Estirenos/química
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