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1.
Food Chem ; 333: 127516, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32683261

RESUMO

Benzotriazoles (BTRs) and benzothiazoles (BTs) are two groups of emerging concern and high production volume contaminants. Via the biomagnification of the food web, they could jeopardize human health. In this work, rapid determining the presence of five BTRs and two BTs in marketed fish was performed by a novel double-vortex-ultrasonic assisted matrix solid-phase dispersion (DVUA-MSPD) and UHPLC-electrospray ionization (+)-quadrupole time-of-flight mass spectrometry detection. Unlike traditional MSPD, we simplified the method without the use of mortar/pestle and SPE-column procedures. The DVUA-MSPD factors were screened by a multilevel categorical design, and then optimized by Box-Behnken Design plus with response surface methodology. The limits of quantification were 0.15-2 ng g-1 (dry weight). The satisfactory average recovery ranged from 70% to 93% with RSDs less than 9%. The developed method was successfully applied for the rapid determination of selected BTRs and BTs in fish samples at trace-level.


Assuntos
Benzotiazóis/química , Peixes/metabolismo , Extração em Fase Sólida/métodos , Animais , Benzotiazóis/análise , Benzotiazóis/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray , Ultrassom
2.
Nat Commun ; 11(1): 2809, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32499559

RESUMO

Formation of membrane-less organelles via liquid-liquid phase separation is one way cells meet the biological requirement for spatiotemporal regulation of cellular components and reactions. Recently, tau, a protein known for its involvement in Alzheimer's disease and other tauopathies, was found to undergo liquid-liquid phase separation making it one of several proteins associated with neurodegenerative diseases to do so. Here, we demonstrate that tau forms dynamic liquid droplets in vitro at physiological protein levels upon molecular crowding in buffers that resemble physiological conditions. Tau droplet formation is significantly enhanced by disease-associated modifications, including the AT8 phospho-epitope and the P301L tau mutation linked to an inherited tauopathy. Moreover, tau droplet dynamics are significantly reduced by these modified forms of tau. Extended phase separation promoted a time-dependent adoption of toxic conformations and oligomerization, but not filamentous aggregation. P301L tau protein showed the greatest oligomer formation following extended phase separation. These findings suggest that phase separation of tau may facilitate the formation of non-filamentous pathogenic tau conformations.


Assuntos
Extração Líquido-Líquido , Proteínas tau/química , Animais , Benzotiazóis/química , Encéfalo/metabolismo , Linhagem Celular , Epitopos/química , Proteínas de Fluorescência Verde/química , Humanos , Insetos , Mutação , Conformação Proteica , Domínios Proteicos , Proteínas Recombinantes/química , Análise de Regressão
3.
Proc Natl Acad Sci U S A ; 117(21): 11265-11273, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32439711

RESUMO

The nucleation of Alzheimer-associated Aß peptide monomers can be catalyzed by preexisting Aß fibrils. This leads to autocatalytic amplification of aggregate mass and underlies self-replication and generation of toxic oligomers associated with several neurodegenerative diseases. However, the nature of the interactions between the monomeric species and the fibrils during this key process, and indeed the ultrastructural localization of the interaction sites have remained elusive. Here we used NMR and optical spectroscopy to identify conditions that enable the capture of transient species during the aggregation and secondary nucleation of the Aß42 peptide. Cryo-electron microscopy (cryo-EM) images show that new aggregates protrude from the entire length of the progenitor fibril. These protrusions are morphologically distinct from the well-ordered fibrils dominating at the end of the aggregation process. The data provide direct evidence that self-replication through secondary nucleation occurs along the sides of fibrils, which become heavily decorated under the current solution conditions (14 µM Aß42, 20 mM sodium phosphate, 200 µM EDTA, pH 6.8).


Assuntos
Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/ultraestrutura , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/ultraestrutura , Doença de Alzheimer/patologia , Amiloide/metabolismo , Amiloide/ultraestrutura , Peptídeos beta-Amiloides/química , Benzotiazóis/química , Benzotiazóis/metabolismo , Microscopia Crioeletrônica , Humanos , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética , Fragmentos de Peptídeos/química , Imagem com Lapso de Tempo
4.
Arch Biochem Biophys ; 686: 108373, 2020 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-32325089

RESUMO

Non-enzymatic protein glycation results in the formation of advanced glycation end products (AGEs) leads to the pathogenesis of long-term diabetic complications. Iridin (ID), an antioxidant, plays an important role in protecting against oxidative stress and could therefore be an efficacious anti-glycating regimen. Herein, we assessed the anti-glycating potential of ID against d-ribose induced glycation of bovine serum albumin (BSA) by various biophysical and biochemical techniques. Our results from several physicochemical assays advocated that ID was able to evidently prevent the AGEs generation via reducing hyperchromicity, early glycation products (EGPs), carbonyl content (CC), hydroxymethyl furfural (HMF) content, production of fluorescent AGEs, protection against loss of secondary structure (i.e. α-helix and ß-sheets) of proteins, increasing the free lysine and free arginine content, reduced binding of congo red (CR), and reduced thioflavin T (ThT) and 8-aninilo-1-napthalene sulphonate (ANS)-specific fuorescence in glycated-BSA (Gly-BSA). On the basis of these findings, we concluded that ID possesses the significant anti-glycation potential and may be established as a remarkable anti-AGEs therapeutic agent. Further in-vivo and clinical studies are still warranted to uncover the therapeutic effects of ID against age-related as well as metabolic diseases.


Assuntos
Antioxidantes/química , Protaminas/química , Ribose/química , Soroalbumina Bovina/química , Arginina/química , Benzotiazóis/química , Sítios de Ligação , Corantes Fluorescentes/química , Produtos Finais de Glicação Avançada/química , Glicosilação , Lisina/química , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Ligação Proteica , Estrutura Secundária de Proteína
6.
Arch Biochem Biophys ; 683: 108319, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32101762

RESUMO

Eukaryotic double-ring chaperonin TRiC is an ATP-dependent protein-folding machine. Most of its substrates are known to form large ordered structures from multiple polypeptide chains. Since these structures are similar to fibrillar and oligomeric forms of amyloidogenic proteins, we hypothesized that TRiC may play a role in the development of neurodegenerative diseases of amyloid nature including prion diseases. Enzyme-linked immunosorbent assay showed that monomeric, oligomeric and fibrillar forms of prion protein (PrP) bind strongly to chaperonin TRiC, whereas glycation reduces the prion protein affinity for chaperonin. Nevertheless, dynamic light scattering, electron microscopy and thioflavin T fluorescence confirmed that all studied forms of PrP undergo an amyloid transformation after interaction with chaperonin, but different forms of prion protein are capable of having different effects on the functional state of TRiC. For example, prion protein monomers completely block its ability to reactivate the chaperonin's natural substrate - sperm-specific glyceraldehyde-3-phosphate dehydrogenase (GAPDS). At the same time, PrP oligomers and fibrils only partially prevent the reactivation of GAPDS upon the action of TRiC. The monomeric forms of prion protein glycated by methylglyoxal do not inhibit, but only slow down the chaperone-dependent reactivation of GAPDS. Thus, the interaction of amyloidogenic proteins with chaperonins could cause cell malfunction.


Assuntos
Chaperonina com TCP-1/química , Chaperoninas/química , Proteínas Priônicas/química , Amiloide/química , Animais , Benzotiazóis/química , Bovinos , Glicosilação , Humanos , Luz , Masculino , Microscopia Eletrônica , Doenças Neurodegenerativas/metabolismo , Príons/metabolismo , Ligação Proteica , Conformação Proteica , Dobramento de Proteína , Proteínas Recombinantes/química , Espalhamento de Radiação , Testículo/metabolismo
7.
J Med Chem ; 63(8): 3868-3880, 2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31940200

RESUMO

Farnesoid X receptor (FXR) agonists are emerging as important potential therapeutics for the treatment of nonalcoholic steatohepatitis (NASH) patients, as they exert positive effects on multiple aspects of the disease. FXR agonists reduce lipid accumulation in the liver, hepatocellular inflammation, hepatic injury, and fibrosis. While there are currently no approved therapies for NASH, the bile acid-derived FXR agonist obeticholic acid (OCA; 6-ethyl chenodeoxycholic acid) has shown promise in clinical studies. Previously, we described the discovery of tropifexor (LJN452), the most potent non-bile acid FXR agonist currently in clinical investigation. Here, we report the discovery of a novel chemical series of non-bile acid FXR agonists based on a tricyclic dihydrochromenopyrazole core from which emerged nidufexor (LMB763), a compound with partial FXR agonistic activity in vitro and FXR-dependent gene modulation in vivo. Nidufexor has advanced to Phase 2 human clinical trials in patients with NASH and diabetic nephropathy.


Assuntos
Benzotiazóis/uso terapêutico , Ácido Quenodesoxicólico/análogos & derivados , Dieta Hiperlipídica/efeitos adversos , Isoxazóis/uso terapêutico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Receptores Citoplasmáticos e Nucleares/agonistas , Animais , Benzotiazóis/química , Ácido Quenodesoxicólico/química , Ácido Quenodesoxicólico/uso terapêutico , Cães , Humanos , Isoxazóis/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/sangue , Hepatopatia Gordurosa não Alcoólica/etiologia , Estrutura Terciária de Proteína , Ratos , Resultado do Tratamento
8.
J Enzyme Inhib Med Chem ; 35(1): 424-431, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31899985

RESUMO

A series of 16 novel benzenesulfonamides incorporating 1,3,5-triazine moieties substituted with aromatic amines, dimethylamine, morpholine and piperidine were investigated. These compounds were assayed for antioxidant properties by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, 2,2`-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical decolarisation assay and metal chelating methods. They were also investigated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase, which are associated with several diseases such as Alzheimer, Parkinson and pigmentation disorders. These benzenesulfonamides showed moderate DPPH radical scavenging and metal chelating activity, and low ABTS cation radical scavenging activity. Compounds 2 b, 3d and 3 h showed inhibitory potency against AChE with % inhibition values of >90. BChE was also effectively inhibited by most of the synthesised compounds with >90% inhibition potency. Tyrosinase was less inhibited by these compounds.


Assuntos
Acetilcolinesterase/efeitos dos fármacos , Antioxidantes/farmacologia , Butirilcolinesterase/efeitos dos fármacos , Inibidores da Colinesterase/farmacologia , Inibidores Enzimáticos/farmacologia , Monofenol Mono-Oxigenase/antagonistas & inibidores , Sulfonamidas/química , Sulfonamidas/farmacologia , Triazinas/química , Benzotiazóis/química , Compostos de Bifenilo/química , Picratos/química , Ácidos Sulfônicos/química
9.
J Enzyme Inhib Med Chem ; 35(1): 524-538, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31939313

RESUMO

A series of nitrogen heterocycles containing α-ethoxyphenylpropionic acid derivatives were designed as dual PPARα/γ agonist ligands for the treatment of type 2 diabetes (T2D) and its complications. 6-Benzoyl-benzothiazol-2-one was the most tolerant of the tested heterocycles in which incorporation of O-methyl oxime ether and trifluoroethoxy group followed by enantiomeric resolution led to the (S)-stereoisomer 44 b displaying the best in vitro pharmacological profile. Compound 44 b acted as a very potent full PPARγ agonist and a weak partial agonist on the PPARα receptor subtype. Compound 44 b showed high efficacy in an ob/ob mice model with significant decreases in serum triglyceride, glucose and insulin levels but mostly with limited body-weight gain and could be considered as a selective PPARγ modulator (SPPARγM).


Assuntos
Benzotiazóis/farmacologia , Hipoglicemiantes/farmacologia , PPAR alfa/agonistas , PPAR gama/agonistas , Fenilpropionatos/farmacologia , Animais , Benzotiazóis/síntese química , Benzotiazóis/química , Células COS , Chlorocebus aethiops , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Relação Dose-Resposta a Droga , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Ligantes , Masculino , Camundongos , Camundongos Obesos , Simulação de Acoplamento Molecular , Estrutura Molecular , PPAR alfa/genética , PPAR gama/genética , Fenilpropionatos/síntese química , Fenilpropionatos/química , Relação Estrutura-Atividade
10.
Nucleic Acids Res ; 48(3): 1108-1119, 2020 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-31912160

RESUMO

G-quadruplex (G4) DNA structures are linked to key biological processes and human diseases. Small molecules that target specific G4 DNA structures and signal their presence would therefore be of great value as chemical research tools with potential to further advance towards diagnostic and therapeutic developments. However, the development of these types of specific compounds remain as a great challenge. In here, we have developed a compound with ability to specifically signal a certain c-MYC G4 DNA structure through a fluorescence light-up mechanism. Despite the compound's two binding sites on the G4 DNA structure, only one of them result in the fluorescence light-up effect. This G-tetrad selectivity proved to originate from a difference in flexibility that affected the binding affinity and tilt the compound out of the planar conformation required for the fluorescence light-up mechanism. The intertwined relation between the presented factors is likely the reason for the lack of examples using rational design to develop compounds with turn-on emission that specifically target certain G4 DNA structures. However, this study shows that it is indeed possible to develop such compounds and present insights into the molecular details of specific G4 DNA recognition and signaling to advance future studies of G4 biology.


Assuntos
DNA/química , Corantes Fluorescentes , Quadruplex G , Benzimidazóis/química , Benzotiazóis/química , Corantes Fluorescentes/química , Genes myc , Simulação de Dinâmica Molecular
11.
Nucleic Acids Res ; 48(4): 1681-1690, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-31950160

RESUMO

I-motif DNAs have been widely employed as robust modulating components to construct reconfigurable DNA nanodevices that function well in acidic cellular environments. However, they generally display poor interactivity with fluorescent ligands under these complex conditions, illustrating a major difficulty in utilizing i-motifs as the light-up system for label-free DNA nanoassemblies and bioimaging. Towards addressing this challenge, here we devise new types of i-motif/miniduplex hybrid structures that display an unprecedentedly high interactivity with commonly-used benzothiazole dyes (e.g. thioflavin T). A well-chosen tetranucleotide, whose optimal sequence depends on the used ligand, is appended to the 5'-terminals of diverse i-motifs and forms a minimal parallel duplex thereby creating a preferential site for binding ligands, verified by molecular dynamics simulation. In this way, the fluorescence of ligands can be dramatically enhanced by the i-motif/miniduplex hybrids under complex physiological conditions. This provides a generic light-up system with a high signal-to-background ratio for programmable DNA nanoassemblies, illustrated through utilizing it for a pH-driven framework nucleic acid nanodevice manipulated in acidic cellular membrane microenvironments. It enables label-free fluorescence bioimaging in response to extracellular pH change.


Assuntos
Técnicas Biossensoriais , DNA/isolamento & purificação , Ácidos Nucleicos/genética , Motivos de Nucleotídeos/genética , Benzotiazóis/química , DNA/química , Corantes Fluorescentes/química , Quadruplex G , Humanos , Ligantes , Simulação de Dinâmica Molecular , Ácidos Nucleicos/química , Espectrometria de Fluorescência
12.
Chem Commun (Camb) ; 56(11): 1681-1684, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31939961

RESUMO

A functionalized dumbbell probe (FDP) based amplification method, termed as a cascading exponential amplification DNA machine (CEA-DNA machine), has been developed to autonomously accumulate single G-quadruplexes (SGQs) and twin-G-quadruplexes (TGQs) for robust fluorescence signal-on probing of miRNA-21.


Assuntos
DNA/química , MicroRNAs/sangue , Técnicas de Amplificação de Ácido Nucleico/métodos , Espectrometria de Fluorescência/métodos , Benzotiazóis/química , Técnicas Biossensoriais/métodos , Linhagem Celular Tumoral , DNA/genética , Sondas de DNA/química , Sondas de DNA/genética , Corantes Fluorescentes/química , Quadruplex G , Humanos , Sequências Repetidas Invertidas , Limite de Detecção , MicroRNAs/genética , Hibridização de Ácido Nucleico
13.
Mini Rev Med Chem ; 20(1): 12-23, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31288719

RESUMO

Benzothiazole is an organic compound bearing a heterocyclic nucleus (thiazole) which imparts a broad spectrum of biological activities to it. The significant and potent activity of benzothiazole moiety influenced distinctively by nature and position of substitutions. This review summarizes the effect of various substituents in recent trends and approaches to design and develop novel benzothiazole derivatives for anticancer potential in different cell lines by interpreting the Structure- Activity Relationship (SAR) and mechanism of action of a wide range of derivatives. The list of derivatives is categorized into different groups and reviewed for their anticancer activity. The structure-activity relationship for the various derivatives revealed an excellent understanding of benzothiazole moiety in the field of cancer therapy against different cancer cell line. Data obtained from the various articles showed the potential effect of benzothiazole moiety and its derivatives to produce the peculiar and significant lead compound. The important anticancer mechanisms found are tyrosine kinase inhibition, topoisomerase inhibition and induction of apoptosis by Reactive Oxygen Species (ROS) activation. Therefore, the design and development of novel benzothiazole have broad scope in cancer chemotherapy.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Benzotiazóis/química , Benzotiazóis/farmacologia , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Benzotiazóis/uso terapêutico , Desenvolvimento de Medicamentos/métodos , Humanos , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Relação Estrutura-Atividade
14.
Appl Biochem Biotechnol ; 190(3): 949-965, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31630339

RESUMO

Alzheimer's disease (AD) is related to the anomalous binding that occurs between amyloid-ß peptide (Aß) and copper ion, through imidazole ring of histidine (His), as stated in the literature. It is also known that high-affinity metal ion chelators can be pharmacologically used as a possible therapeutic approach. In this work, we tested the ability "in vitro" of chitosan (Chi) to reduce Aß aggregation and Thioflavin T binding assay indicated that chitosan has affinity for Aß and interferes in its aggregation. We also tested the ability of Chi to uptake copper ions in the presence of Aß or His. Equilibrium data reveals that chitosan acted as an effective chelating agent competing with Aß and histidine for copper binding. The addition of histidine or Aß in the system promotes an unfolding of chitosan chains, as verified by small-angle X-ray scattering. Extended X-ray absorption fine structure and XPS spectra show that new copper interactions with groups containing nitrogen in the presence of histidine may occur. These results can help understanding fundamental chemical interactions among species detected in AD and biopolymers, opening up possibilities for new treatment approaches for this disease.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Quitosana/metabolismo , Cobre/metabolismo , Histidina/metabolismo , Doença de Alzheimer/metabolismo , Benzotiazóis/química , Biopolímeros/metabolismo , Fluorescência , Humanos
15.
Biochemistry ; 59(4): 425-435, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31854188

RESUMO

Aggregations of ß-amyloid (Aß) and α-synuclein (αS) into oligomeric and fibrillar assemblies are the pathological hallmarks of Alzheimer's and Parkinson's diseases, respectively. Although Aß and αS affect different regions of the brain and are separated at the cellular level, there is evidence of their eventual interaction in the pathology of both disorders. Characterization of interactions of Aß and αS at various stages of their aggregation pathways could reveal mechanisms and therapeutic targets for the prevention and cure of these neurodegenerative diseases. In this study, we comprehensively examined the interactions and their molecular manifestations using an array of characterization tools. We show for the first time that αS monomers and oligomers, but not αS fibrils, inhibit Aß fibrillization while promoting oligomerization of Aß monomers and stabilizing preformed Aß oligomers via coassembly, as judged by Thioflavin T fluorescence, transmission electron microscopy, and SDS- and native-PAGE with fluorescently labeled peptides/proteins. In contrast, soluble Aß species, such as monomers and oligomers, aggregate into fibrils, when incubated alone under the otherwise same condition. Our study provides evidence that the interactions with αS soluble species, responsible for the effects, are mediated primarily by the C-terminus of Aß, when judged by competitive immunoassays using antibodies recognizing various fragments of Aß. We also show that the C-terminus of Aß is a primary site for its interaction with αS fibrils. Collectively, these data demonstrate aggregation state-specific interactions between αS and Aß and offer insight into a molecular basis of synergistic biological effects between the two polypeptides.


Assuntos
Peptídeos beta-Amiloides/química , Amiloide/química , alfa-Sinucleína/química , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Benzotiazóis/química , Encéfalo/metabolismo , Eletroforese em Gel de Poliacrilamida/métodos , Humanos , Microscopia de Força Atômica/métodos , Microscopia Eletrônica de Transmissão/métodos , Doenças Neurodegenerativas/metabolismo , Doença de Parkinson/metabolismo , Fragmentos de Peptídeos/química , Agregação Patológica de Proteínas/metabolismo
16.
Carbohydr Polym ; 227: 115348, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590881

RESUMO

Ecofriendly chitosan-gelatin (Ch-ge) bio-composite films containing Quercetin-starch (Q) were synthesized using solution casting method. Physicochemical characteristics and mechanical properties of the resulting chitosan-gelatin containing Quercetin-starch films (Ch-ge-Q) were studied using UV, FTIR, XRD and SEM techniques. The films were also investigated for their swelling, water-vapor permeability (WVP), water solubility properties. The FTIR spectra confirmed the chemical interactions between the chitosan-gelatin and Q. Surface morphology of prepared film was analyzed by the SEM imaging while XRD spectra suggest the expanded crystallinity of the film with the addition of Q. The film also showed enhanced barrier property against UV rays. The reduction of water-vapor permeability and increase in tensile strength while a decrease in elongation at break has been observed in the Ch-ge-Q film compared to Ch-ge film. The antibacterial activity of Ch-ge-Q film against both gram positive (B. substilis) and gram negative (E. coli) bacteria suggested the Q loaded Ch-ge films as more feasible antibacterial candidate especially against the strain E. coli. The antioxidant activity of the Ch-ge-Q film was evaluated using the DPPH and ABTS as standards and corresponded to 81.45% of DPPH and 72.2% of ABTS scavenging activities. It was observed that the film containing Quercetin-starch presented superior antioxidant activity results in comparison to Ch-ge film promising its application in food packaging.


Assuntos
Antibacterianos/química , Antioxidantes/química , Quitosana/química , Embalagem de Alimentos , Gelatina/química , Quercetina/química , Bacillus subtilis/crescimento & desenvolvimento , Benzotiazóis/química , Compostos de Bifenilo/química , Escherichia coli/crescimento & desenvolvimento , Oxigênio/química , Permeabilidade , Picratos/química , Ácidos Sulfônicos/química , Raios Ultravioleta , Água/química
17.
Carbohydr Polym ; 227: 115362, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590882

RESUMO

A new polysaccharide (pFSP) was first isolated from the originally discarded fibrous roots part of Chinese traditional herb, Bletilla striata. pFSP was composed of D-glucose, D-galactose and D-mannose in a molar ratio of 1: 2.03: 3.45 with molecular weight of 9.1 × 104 Da. It could effectively scavenge DPPH and superoxide radicals with inhibition rate of 64.47% and 72.27% at 5.0 mg/ml, higher than that of polysaccharide from Bletilla striata tuber. Structural investigations of the periodate oxidation studies and Smith-degradation as well as the FT-IR spectroscopy were performed, and combined with 1D and 2D NMR spectroscopy, the repeating unit of pFSP contained (1→4)-linked-α-D-Glcp, (1→4)-linked-ß-D-Manp and (1→3,6)-linked-ß-D-Manp units, together with the branches of (1→6)-linked-ß-D-Galp and terminated with (1→)-linked-ß-D-Manp residue.


Assuntos
Antioxidantes/química , Orchidaceae , Polissacarídeos/química , Benzotiazóis/química , Compostos de Bifenilo/química , Espectroscopia de Ressonância Magnética , Picratos/química , Raízes de Plantas , Ácidos Sulfônicos/química , Superóxidos/química
18.
Carbohydr Polym ; 229: 115395, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826411

RESUMO

Oxygen protection/isolation is imperative to prevent the lipid oxidation since oxygen molecule is an ultimate quencher in photon conversion process. Inspired by the structural buildup of seeds from oil crops, a sustainable solid particle stabilizer with novel antioxidant activity was prepared by using cellulose and polyphenol. In this work, bacterial cellulose (BC) nanofibrils modified by tea polyphenols (TPs) was prepared and used as Pickering emulsifier for the O/W emulsion. BC nanofibirls exhibited excellent adsorption capacity up to 55 µg/mg, and the adsorption kinetics between BC and TPs were further investigated. After modification, the interfacial diffusion rate constant of BC was significantly increased to from 0.43 to 1.21 mN m-1 s-0.5. Moreover, the obtained O/W interfacial modulus of the dilatational elasticity was increased from 58 to 130 mN/m. Furthermore, the emulsions exhibited excellent free-radical scavenging activity at oil-water interface, suggesting a potential application in usage to extend the lifespan of the food containing polyunsaturated fats.


Assuntos
Antioxidantes/química , Celulose/química , Polifenóis/química , Adsorção , Benzotiazóis/química , Compostos de Bifenilo/química , Emulsões/química , Oxigênio/química , Picratos/química , Ácidos Sulfônicos/química , Chá
19.
Carbohydr Polym ; 229: 115355, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826432

RESUMO

To ascertain the preliminary structural characteristics and biological activity of different fractions of polysaccharides from Sagittaria sagittifolia L. (SPCs) by ultrasonic assisted extraction (UAE), four new polysaccharides (SPC-60, SPC-70, SPC-80 and SPC-90) were successively fractionated by ethanol. The results implied that except for neutral sugar, four contained proteins and uronic acids in their structure, which were further confirmed by the ultraviolet and infrared spectra. Molecular weight and monosaccharide composition analysis exhibited that SPC-60 (52.0 kDa), SPC-70 (294.9 kDa), SPC-80 (230.6 kDa) and SPC-90 (229.4 kDa) were a neutral polysaccharide composed of rhamnose, arabinose, xylose, mannose, glucose and galactose with dramatically different mole ratios. In addition, SPC-70 exhibited stronger antioxidant activity in vitro than the other three components. SPCs could significantly promote macrophage proliferation, NO release and phagocytosis. Thus, these results provided a reference for applications of S. sagittifolia L. polysaccharides which would benefit the development of industry and agriculture.


Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Polissacarídeos/química , Polissacarídeos/farmacologia , Sagittaria , Animais , Benzotiazóis/química , Compostos de Bifenilo/química , Frutas/química , Radical Hidroxila/química , Camundongos , Óxido Nítrico/metabolismo , Fagocitose/efeitos dos fármacos , Picratos/química , Células RAW 264.7 , Ácidos Sulfônicos/química
20.
Carbohydr Polym ; 229: 115409, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826479

RESUMO

In this study, the seed polysaccharides (PCSP) was ultrasonic-assisted extracted from Pouteria campechiana and optimized by response surface method (RSM). After separation and purification by DEAE-52 cellulose column and Sephadex G-75 glucan gel column, the pure polysaccharide component of PCSPa-1 was obtained, and its structure and antioxidant activity were analyzed. The results showed that the optimal parameters of PCSP with maximum yields (15.94%) were ultrasonic temperature of 79 °C, ultrasonic time of 69 min, and liquid to material ratio of 41 mL/g. The molecular weight of PCSPa-1 was 67900 Da. PCSPa-1 consisted of glucose and mannose with a molar ratio of 86.65:4.62, and the glycosidic bond mainly included →4)-α-d-Glc(1→ and →6)-α-d-Glc(1→. Scanning electron microscopy showed that PCSPa-1 was a strip structure with a smooth surface. In addition, PCSPa-1 had strong scavenging capacity to 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis- (3-ethylbenzthiaz oline-6-sulphonic acid) (ABTS), hydroxyl radical, and superoxide radical. Polysaccharides of Pouteria campechiana seeds could be exploited as a natural antioxidant.


Assuntos
Antioxidantes/química , Polissacarídeos/química , Pouteria , Benzotiazóis/química , Compostos de Bifenilo/química , Radical Hidroxila , Picratos/química , Sementes , Ácidos Sulfônicos/química , Superóxidos/química
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