Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 55
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Anal Methods ; 13(37): 4314-4319, 2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34476425

RESUMO

A key challenge for the discrete distribution-based Förster resonance energy transfer system (D-FRET) is the reduced intensity and stability of signal probes in complex biological matrices. Here, we present a spatially confined FRET (SC-FRET) probe with a stable structure and strong signal output. It consists of multivalent FRET pairs labeled with FAM or TAMRA. In this assay, p53 DNA was chosen as a model hairpin probe (HP), and two kinds of branched DNA probes (ssDNA-FAM, ssDNA-TAMRA) were involved. Under the action of p53 DNA, the unfolded HP acts as a primer to initiate polymerization extension of KFP polymerase and cleavage of Nb.BbvCI endonuclease, which produces plenty of ssDNA (primer-DNA). The branched DNA is designed to have the same binding core and different sticky ends, the core part of which can self-assemble to form X-shaped branched DNA (X-FAM or X-TAMRA), and the sticky ends of which are complementary to the primer-DNA. Therefore, the primer-DNAs released during the polymerization cleavage process will combine a large number of X-FAM and X-TAMRA in a limited space through complementary base pairing. Fluorescence was transferred from FAM to TAMRA, and a strong FRET response was generated by the locational effects. The proposed SC-FRET system based on the multivalent assembly of branched DNA exhibited a strong FRET response with an LOD of 0.01394 pM. Importantly, it also showed a high-contrast and stable FRET response in HeLa cells. Its superior biological stability is attributed to the large steric hindrance of the compact and rigid frame of the SC-FRET probe, which helps prevent intracellular degradation and provides a powerful tool for biomedical research.

2.
Talanta ; 235: 122814, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517670

RESUMO

Simple and sensitive detection of telomerase activity is of vital importance for both early diagnosis and therapy of malignant tumors. Inspired by DNA-biobarcode amplification reported by Chad A. Mirkin, we developed a facile DNA-biobarcode-like SERS-based copper-mediated signal amplification strategy for sensitive detection of telomerase activity. In this strategy, a duplex DNA constructed by hybridization of a copper oxide nanoparticle (CuO NP)-labeled reporting sequence (RS) with the telomerase primer sequence (TS) is ingeniously designed, and anchored on the magnetic bead (MB) to build the CuO NPs-encoded magnetic bead (MB-CuO NPs) detection probe. Upon selective sensing of telomerase, telomerase elongation reaction and structure change of TS products make the CuO NP-RS displace and separate from MB. The separated CuO NPs are dissolved into a mass of Cu2+, which prompt monodisperse dopamine-functionalized AgNPs (D-AgNPs) signal probe into aggregation, resulting in color changes and significantly enhancing of SERS signal. The SERS signal increases with the increase of Cu2+, which is directly proportional to the telomerase. Benefiting from the transformation of CuO NP to Cu2+ with a high amplification effect, this strategy could realize the telomerase activity measurement down to 3 HeLa cells and a dynamic range of 10-10000 cells. It shows a significant improvement of sensitivity without need for other enzymes and elaborate design, which escapes from the complicated manipulations and design in polymerase chain reaction (PCR) and DNA amplification techniques. Moreover, with this strategy, telomerase activities of different cell lines and telomerase inhibitors screening were successfully performed. Significantly, it can also be utilized for visual detection of telomerase, which validates the potential on-site application and its application as point-of-care testing (POCT) for efficient monitoring. Given the high-performance for telomerase analysis, the strategy has a promising application in biological detection and clinical diagnosis, as well as point-of-care tests.


Assuntos
Técnicas Biossensoriais , Telomerase , Cobre , DNA , Células HeLa , Humanos , Técnicas de Amplificação de Ácido Nucleico , Telomerase/genética , Telomerase/metabolismo
3.
Food Chem ; 368: 130864, 2021 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-34438172

RESUMO

Ultra-high pressure (UHP) is a novel non-thermal pretreatment method in food processing for improving the extraction yield of polyphenols and functional properties. The present work investigated the phenolic profiles, antioxidant activities, and cytoprotective effects of the free, esterified, and insoluble-bound phenolic fractions from mango leaves before and after ultra-high pressure (UHP) treatment. UHPLC-Q-Orbitrap-MS/MS analysis resulted in the identification of 42 phenolic compounds in the different phenolic forms. UHP pretreatment could significantly influence the contents of total phenols, total flavonoids and individual compounds in the different phenolic fractions (p < 0.05). After UHP pretreatment, these phenolic fractions exhibited greater antioxidant activity, and inhibited reactive oxygen species production and cell apoptosis (p < 0.05). Meanwhile, IBP were the most potential antioxidative and cytoprotective ingredients. Therefore, UHP pretreated mango leaves with enhanced bioactivity could be used as biological agents in the health food industry to improve its application and economic values.

4.
Food Chem Toxicol ; 156: 112506, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34389369

RESUMO

E Se tea, processed by the fresh leaves of Malus toringoides (Rehd.) Hughes, is a traditional herbal tea with various human benefits. The present study was aimed to evaluate the toxicity and hypolipidemic effect of aqueous-ethanol extract (EE) and hot-water extract (WE) from E Se tea. Eight main chemical constituents in EE and WE were respectively identified and quantified by UHPLC-HRMS/MS. EE is rich in TPC and TFC, while WE had higher TPS content. Both EE and WE exhibited strong antioxidant activity with no significant difference. The acute toxicity study revealed that the LD50 values were higher than 5000 mg/kg, while both WE and EE had no significant adverse effect in rats by subacute toxicity assay. However, the triglyceride (TG) content in experiment groups (male) and highest doses groups (female) significantly decreased. Furthermore, the hypolipidemic effect of WE and EE were performed on high fat diet induced hyperlipidemic rats. The result exhibited that either WE or EE could effectively regulate lipid droplet accumulation in liver, and reduce the adipocyte size. These results demonstrated that these two extracts from E Se tea could be regarded as a potential functional dietary supplement in preventing and treating diet induced metabolic diseases.

5.
Phytomedicine ; 91: 153684, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34400050

RESUMO

BACKGROUND: Melodinus cochinchinensis (Lour.) Merr. is a medicinal plant, which is used as a folk medicine for treating meningitis and fractures. However, the anti-inflammatory activity of total alkaloid extract from M. cochinchinensis (MCTA) and its molecular mechanism are still not studied. PURPOSE: The aim of this study is to investigate the main chemical constituents of MCTA and explore its anti-inflammatory potential in both in vitro and in vivo assessments. METHODS: UHPLC-ESI-HRMS/MS was applied to analyze the chemical profiling. The anti-inflammatory efficacy of MCTA was evaluated on lipopolysaccharide (LPS) induced RAW 264.7 cells and two common inflammation models in mice. The production of pro-inflammatory mediator and cytokine was tested using the ELISA method. The pathological change was analyzed by histological assessment. The expression of NF-κB, MAPKs and PPAR-γ proteins was evaluated using western blot analysis. RESULTS: A total of 21 monoterpenoid indole alkaloids (MIAs) were characterized by UHPLC-ESI-HRMS/MS. Aspidospermine- and quinolone-type alkaloids were found to be the major compounds. MCTA significantly decreased the production of NO, IL-1ß, IL-6 and TNF-α in LPS-induced RAW 264.7 macrophages. MCTA significantly inhibited the phosphorylation of ERK1/2, JNK and p38 MAPK, suppressed the NF-κB transcriptional activation and improved the PPAR-γ expression. Moreover, the in vivo experiment exhibited that MCTA pretreatment markedly alleviated the xylene-induced ear edema and carrageenan-induced paw edema in mice and decreased the IL-1ß, IL-6 and TNF-α expressions. CONCLUSION: MCTA is rich in MIAs and exhibited a significant inhibitory effect on the production proinflammatory cytokines. The mechanism might be related to the inhibition of activation of NF-κB and MAPK pathways.


Assuntos
Alcaloides , Anti-Inflamatórios , Apocynaceae/química , Edema , Extratos Vegetais , Alcaloides/farmacologia , Alcaloides/uso terapêutico , Animais , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Citocinas/metabolismo , Edema/tratamento farmacológico , Lipopolissacarídeos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , NF-kappa B/metabolismo , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Células RAW 264.7
6.
Nat Commun ; 12(1): 4966, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404784

RESUMO

Although chirality is an ever-present characteristic in biology and some artificial molecules, controlling the chirality and demystifying the chirality origin of complex assemblies remain challenging. Herein, we report two homochiral Ag14 nanoclusters with inherent chirality originated from identical rotation of six square faces on a Ag8 cube driven by intra-cluster π···π stacking interaction between pntp- (Hpntp = p-nitrothiophenol) ligands. The spontaneous resolution of the racemic (SD/rac-Ag14a) to homochiral nanoclusters (SD/L-Ag14 and SD/R-Ag14) can be realized by re-crystallizing SD/rac-Ag14a in acetonitrile, which promotes the homochiral crystallization in solid state by forming C-H···O/N hydrogen bonds with nitro oxygen atoms in pntp- or aromatic hydrogen atoms in dpph (dpph = 1,6-bis(diphenylphosphino)hexane) on Ag14 nanocluster. This work not only provides strategic guidance for the syntheses of chiral silver nanoclusters in an all-achiral environment, but also deciphers the origin of chirality at molecular level by identifying the special effects of intra- and inter-cluster supramolecular interactions.


Assuntos
Cristalização , Compostos Organometálicos/química , Fenômenos Físicos , Prata/química , Acetonitrilas/química , Cristalografia por Raios X , Hexanos , Hidrogênio , Ligação de Hidrogênio , Modelos Moleculares , Conformação Molecular , Oxigênio , Rotação
7.
Analyst ; 146(15): 4858-4864, 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34231571

RESUMO

DBP, one of the phthalic acid esters (PAEs), is known as an endocrine disruptor and is toxic to humans in abnormal concentrations. Here, a high-density and ordered SERS substrate based on the self-assembly of triangular Ag nanoplate (TAgNP) arrays is developed for DBP detection. Benefiting from the ordered arrangement and sharp corners of TAgNPS, the arrays can provide sufficient and uniform hotspots for reproducible and highly active SERS effects. Using Rhodamine 6G (R6G) as a reporter molecule, the SERS enhancement factor (EF) of the TAgNP arrays was found to be as high as 1.2 × 107 and the relative standard deviation was 6.56%. As a trial for practical applications, the TAgNP array substrates were used for the detection of dibutyl phthalate (DBP) in edible oils. In this assay, edible oil samples were added to hexane as an organic phase for the formation of the TAgNP arrays, which caused DBP to be loaded at hotspots. DBP in edible oils could be identified at concentrations as low as 10-7 M. This SERS substrate based on the TAgNP arrays has great potential applications in the high sensitivity and reproducible detection of contaminants in food.


Assuntos
Dibutilftalato , Disruptores Endócrinos , Óleos Vegetais , Prata
8.
Analyst ; 146(11): 3679-3685, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-33955434

RESUMO

In the electrochemiluminescence (ECL) field, most reported luminophores were focused on high-triggering potential and short wavelength, which was adverse for the ECL theory study and application at low potentials. Perylene diimide derivatives could emit near-infrared (NIR) ECL at low-triggering potential; however, they are always highly aggregated into a microrod structure and stacked together, which largely limited their application in biological fields such as bio-sensing and bio-imaging. To overcome these obstacles, we designed a novel perylene diimide molecule, namely N,N'-dicaproate sodium-3,4,9,10-perylenedicarboximide (PDI-COONa). This molecule self-assembled into a two-dimensional network nanostructure, which largely decreased the aggregation degree of PDI molecules and provided solid bases for designing lowly-aggregated PDI molecules. Also, the formed nanoluminophore produced strong emission at -0.26 V with an NIR wavelength 700 nm, which should be due to the excited J-type PDI-COO- dimers. Moreover, this network nanoluminophore well-dispersed on graphene oxide (GO) as an ECL nanomaterial to label secondary antibodies and fabricate a sandwiched immunosensor for alpha-fetoprotein (AFP) detection between 0 and -0.6 V. This immunosensor showed a wider linear response for AFP ranging from 0.1 fg mL-1 to 1 µg mL-1 with a low detection limit 0.0353 fg mL-1 compared with other immunosensors based on PDI microrod-modified GO ECL materials. The fabricated immunosensor also showed good feasibility in human serum samples.


Assuntos
Técnicas Biossensoriais , Perileno , Técnicas Eletroquímicas , Humanos , Imunoensaio , Limite de Detecção , Medições Luminescentes
9.
Luminescence ; 36(5): 1272-1276, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33837604

RESUMO

A simple, rapid and highly sensitive method for detection of double-stranded DNA (dsDNA) was developed using a novel fluorescence probe composed of a RecA-GFP fusion protein that had specific recognition of ssDNA complexes (RecA-GFP-DNA filament). The RecA-GFP fusion protein not only had strong fluorescence, but could also occur by homologous recombination. In the presence of the target dsDNA, the complementary ssDNA of the RecA-GFP-DNA filaments invaded one end of the dsDNA chain. In addition, the other end of the ssDNA dissociated the RecA-GFP filaments. An assay of the probe showed a linear relationship with dsDNA concentration in the range 1-11 nM, with a correlation coefficient of 0.9923. The limit of detection for dsDNA was determined experimentally to be 0.3 nM (3δ). Compared with conventional methods, this method has the advantages of simple operation, high specificity, and high sensitivity.


Assuntos
DNA de Cadeia Simples , Recombinases Rec A , DNA/genética , Recombinases Rec A/genética , Recombinases Rec A/metabolismo
10.
Molecules ; 26(7)2021 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-33916551

RESUMO

Vaccinium dunalianum Wight, usually processed as a traditional folk tea beverage, is widely distributed in the southwest of China. The present study aimed to investigate the antioxidant, α-glucosidase and pancreatic lipase inhibitory activities of V.dunalianum extract and isolate the bioactive components. In this study, the crude extract (CE) from the buds of V. dunalianum was prepared by the ultrasound-assisted extraction method in 70% methanol and then purified with macroporous resin D101 to obtain the purified extract (PM). Five fractions (Fr. A-E) were further obtained by MPLC column (RP-C18). Bioactivity assays revealed that Fr. B with 40% methanol and Fr. D with 80% methanol had better antioxidant with 0.48 ± 0.03 and 0.62 ± 0.01 nM Trolox equivalent (TE)/mg extract for DPPH, 0.87 ± 0.02 and 1.58 ± 0.02 nM TE/mg extract for FRAP, 14.42 ± 0.41 and 19.25 ± 0.23 nM TE/mg extract for ABTS, and enzyme inhibitory effects with IC50 values of 95.21 ± 2.21 and 74.55 ± 3.85 for α-glucosidase, and 142.53 ± 11.45 and 128.76 ± 13.85 µg/mL for pancreatic lipase. Multivariate analysis indicated that the TPC and TFC were positively related to the antioxidant activities. Further phytochemical purification led to the isolation of ten compounds (1-10). 6-O-Caffeoylarbutin (7) showed significant inhibitory effects on α-glucosidase and pancreatic lipase enzymes with values of 38.38 ± 1.84 and 97.56 ± 7.53 µg/mL, and had the highest antioxidant capacity compared to the other compounds.


Assuntos
Antioxidantes/isolamento & purificação , Arbutina/análogos & derivados , Ácidos Cafeicos/isolamento & purificação , Flavonoides/isolamento & purificação , Inibidores de Glicosídeo Hidrolases/isolamento & purificação , Lipase/química , Vaccinium/química , alfa-Glucosidases/química , Antioxidantes/química , Arbutina/química , Arbutina/isolamento & purificação , Benzotiazóis/antagonistas & inibidores , Benzotiazóis/química , Compostos de Bifenilo/química , Ácidos Cafeicos/química , Flavonoides/química , Inibidores de Glicosídeo Hidrolases/química , Lipase/antagonistas & inibidores , Lipase/metabolismo , Extração Líquido-Líquido/métodos , Metanol/química , Picratos/química , Extratos Vegetais/química , Folhas de Planta/química , Solventes/química , Sonicação , Ácidos Sulfônicos/antagonistas & inibidores , Ácidos Sulfônicos/química , alfa-Glucosidases/metabolismo
11.
Analyst ; 146(8): 2705-2711, 2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33751013

RESUMO

A novel ratiometric electrochemical biosensing strategy based on T7 exonuclease (T7 Exo)-assisted homogenous target recycling coupling hairpin assembly triggered dual-signal output was proposed for the accurate and sensitive detection of microRNA-141 (miRNA-141). Concretely, in the presence of target miRNA, abundant signal transduction probes were released via the T7 Exo-assisted homogenous target recycling amplification, which could be captured by the specially designed ferrocene-labeled hairpin probe (Fc-H1) on -electrode interface and triggered the nonenzymatic catalytic hairpin assembly (Fc-H1 + MB-H2) to realize the cascade signal amplification and dual-signal output. Through such a conformational change process, the electrochemical signal of Fc (IFc) and MB (IMB) is proportionally and substantially decreased and increased. Therefore, the signal ratio of IMB/IFc can be employed to accurately reflect the true level of original miRNA. Benefiting from the efficient integration of the T7 Exo-assisted target recycle, nonenzymatic hairpin assembly and dual-signal output mode, the proposed sensor could realize the amplified detection of miRNA-141 effectively with a wide detection range from 1 fM to 100 pM, and a detection limit of 200 aM. Furthermore, it exhibits outstanding sequence specificity to discriminate mismatched RNA, acceptable reproducibility and feasibility for real sample. This strategy effectively integrated the advantages of multiple amplification and ratiometric output modes, which could provide an accurate and efficient method in biosensing and clinical diagnosis.


Assuntos
Técnicas Biossensoriais , MicroRNAs , Técnicas Eletroquímicas , Exodesoxirribonucleases , Limite de Detecção , MicroRNAs/genética , Reprodutibilidade dos Testes
12.
NanoImpact ; 21: 100295, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33458449

RESUMO

The COVID-19 pandemic caused by SARS-CoV-2 has posed a huge threat to mankind, deeply endangering healthy states and influencing economic development. COVID-19 has important impacts on the environment as anthropic interventions to nature has been largely reduced after almost all countries implemented partial or complete blockade to curb the spread of the virus. Up to now, a series of studies have focused on the relationship between COVID-19 and the environment from different cities. In this review, we summarized the latest data on the correlation between COVID-19 and environmental changes. As a result, imposing necessary restrictions can help suppress the virus chain while improving air quality in some countries. The significant reduction in NO2 emission, PM2.5 level and other hazardous factors reflected the promising consequence of the efforts made during the lockdown period. It is, sometimes dark clouds have silver linings. It is worth noting that along with these positive outcomes, secondary pollutants such as ozone, however, remained unchanged or even increased significantly. Additionally, medical wastes and plastics pollutants would be increased substantially. The extensive use of masks in daily life and other medical materials is bound to increase the burden of waste disposal and environmental degradation. For the general public, in addition to the physical lesions caused by SARS-CoV-2, confirmed/suspected cases and even the normal group may suffer from mental problems. Based on those mentioned impacts, the way forward depends largely on our attitude and decision. It is indispensable to assess potential deleterious effects and to take preventive measures in time to respond to the post-pandemic era. In this way, potential silver linings will not become temporary.


Assuntos
COVID-19/epidemiologia , COVID-19/psicologia , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Ansiedade/epidemiologia , Ansiedade/psicologia , Biodegradação Ambiental , Depressão/epidemiologia , Depressão/psicologia , Exposição Ambiental , Monitoramento Ambiental , Poluentes Ambientais , Gases , Geografia , Humanos , Resíduos de Serviços de Saúde , Dióxido de Nitrogênio , Ozônio , Material Particulado , Plásticos , Saúde Pública , SARS-CoV-2
13.
Chem Commun (Camb) ; 56(83): 12628-12631, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32959832

RESUMO

Developing convenient and sensitive detection methods for antibiotic residues in food is beneficial for ensuring food quality and human health. The tough challenges that limit the development of sensitive, quantitative, portable, on-the-spot antibiotic detectors are the lack of simple and effective target recognition and signal amplification strategies, and direct digital quantification. Herein, we developed a visual digital quantitative aptasensor, based on a binding-induced 3-D DNA nanomachine signal probe, for the simple and sensitive, on-the-spot detection of antibiotics.


Assuntos
Antibacterianos/análise , DNA/metabolismo , Técnicas Eletroquímicas/métodos , Contaminação de Alimentos/análise , Nanoestruturas/química , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , DNA/química , Sondas de DNA/química , Sondas de DNA/metabolismo , Eletroforese em Gel de Poliacrilamida , Sequências Repetidas Invertidas , Limite de Detecção , Magnetismo
14.
Analyst ; 145(22): 7448, 2020 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-32966362

RESUMO

Correction for 'A facile deoxyuridine/biotin-modified molecular beacon for simultaneous detection of proteins and nucleic acids via a label-free and background-eliminated fluorescence assay' by Fei Yin, et al., Analyst, 2019, 144, 5504-5510, DOI: 10.1039/C9AN01016E.

15.
Anal Methods ; 12(24): 3092-3097, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32930168

RESUMO

Developing a sensitive, low-cost and general sensing platform for the analysis of a DNA biomarker and its mutation is important for early cancer screening. In our work, the tumor suppressor gene-p53 DNA was chosen as the model DNA biomarker due to its vital role in preventing oncogene cancer-inhibiting activity through mediating cellular proliferation and apoptosis. Compared with tumor biopsy, the quantification of p53 DNA and its mutation in biofluids (such as urine) is more convenient due to its simple operation and non-invasiveness. Herein, a label-free amplified fluorescence assay has been developed for p53 DNA in urine samples through the KFP polymerase-driven double strand displacement reactions and a magnetic nanoprobe. First, the ssDNA probe (RP) was designed with antisense sequences for p53 DNA and the Nb.BbvCI endonuclease recognition site. In the presence of p53 DNA, the formed dsDNA between RP and p53 DNA served as an engaging primer to initiate the first strand displacement reaction (SDA) under the action of KFP DNA polymerase and Nb.BbvCI, generating abundant short ssDNA (primer). Subsequently, the resulting primers will initiate the downstream SDA through the primer-hairpin DNA (HPa) binding, opening up, and extension of HPb and HPc under the action of KFP DNA polymerase. In the process of this final DNA polymerization reaction, the primer hybridized on HPa is released and goes on to initiate another round, forming plenty of duplex Y-shaped DNA. With the integration of SYBR Green I (SG I) into these duplex DNA, the amplified label-free fluorescence detection platform for p53 DNA can be achieved. Moreover, a biotin modified nanoprobe (bio-CP) was used to capture the superfluous HP. By performing the separation function, the binding of superfluous HP and SG could be avoided and a low background can be acquired. Benefiting from the abundant SG intercalation sites of Y-shaped DNA and low background signals, this method showed excellent sensitivity with a detection limit of 0.012 nM, and the p53 DNA in urine samples was evaluated, offering a powerful tool for biomedical research and clinical diagnosis.


Assuntos
DNA , Técnicas de Amplificação de Ácido Nucleico , Biotina , DNA/genética , DNA de Cadeia Simples/genética , Polimerização
16.
Chem Commun (Camb) ; 56(75): 11074-11077, 2020 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-32812587

RESUMO

A DNA immobilization-free ECL aptasensor was developed for the detection of 8-hydroxy-2'-deoxygunosine based on the diffusion mediated ECL quenching effect. This ECL aptasensor exhibited a high sensitivity and low detection limit by combining homogeneous DNA reaction with dual signal amplifications: target-induced multi-DNA release and Exo I-assisted target recycling.

17.
J Ethnopharmacol ; 261: 113105, 2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-32590114

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Epigynum auritum has been historically used as a "dai" or traditional medicine for the treatment of inflammation, swelling and severe pain during injury; these may reduce risk of disease and lead to healthier aging. Apart from this, Epigynum auritum extract was also used in arhritis treatment which is also a type of inflammation. Previous phytochemical studies of E. auritum revealed that steroids are main characteristic components with a number of biological activities (especially immunosuppressive and anti-inflammatory activity) Nevertheless, the underlying mechanism of the E. auritum on inflammatory diseases is still unresolved. AIM OF THE STUDY: This study aimed to comparatively investigate the anti-inflammatory potential of different fractions from the extract of E. auritum (EAE), with their possible active ingredients to reveal the underlying mechanism. MATERIALS AND METHODS: The EAE was fractionated by column chromatography with macroporous resin D101 which yielded six fractions. The potential anti-inflammatory properties of different fractions of EAE were evaluated in in vitro and in vivo model. The lipopolysaccharide (LPS)-induced RAW264.7 macrophages cells were used for in vitro studies however two typical acute inflammation murine models (xylene-induced ear edema and carrageenan-induced paw edema) were used for anti-inflammatory studies. The important molecular mechanisms related to inflammation were also analyzed by ELISA, western blotting and immunofluorescence. UHPLC-MS/MS was used to analyze the chemical composition of 100% EAE fraction. RESULTS: Different EAE fractions (especially the Fr. 100% of MeOH:H2O) significantly reduced the productions of NO, ROS, TNF-α, and IL-6 by LPS-induced RAW264.7 macrophages and increased the expression of IL-10. The expression levels of iNOS and COX-2 enzymes were significantly down-regulated by 100% EAE fraction. Furthermore, 100% EAE fraction inhibited the phosphorylation of the ERK1/2, JNK, and p38 MAPK, and reduced the nuclear translocation of NF-κB which prevents its activation by blocking the phosphorylation and degradation of inhibitor protein of IκBα. In addition two inflammatory animal models; xylene-induced ear edema and carrageenan-stimulated paw edema were also developed with significantly ameliorated inflammatory cytokines. The treatment of these inflammatory models with 100% EAE fraction (Fr. 100%) suppressed the expressions of elevated inflammatory cytokines. Besides the UHPLC-HRMS/MS analysis was also carried out in which the androstane analogues were found to be as a main chemical components. CONCLUSION: Different fractions (especially Fr. 100%) exert inhibitory effect on inflammation by regulating the release of inflammatory mediators through the NF-κB and MAPK signaling pathways. The androstane and its derivatives might be performing an important role in the observed anti-inflammatory activity. Therefore, Fr. 100% of EAE could be applied as a potential drug candidate for the prevention and treatment of inflammatory diseases.


Assuntos
Anti-Inflamatórios/farmacologia , Apocynaceae , Mediadores da Inflamação/metabolismo , Inflamação/prevenção & controle , Macrófagos/efeitos dos fármacos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Extratos Vegetais/farmacologia , Animais , Anti-Inflamatórios/isolamento & purificação , Apocynaceae/química , Carragenina , Modelos Animais de Doenças , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Inflamação/induzido quimicamente , Inflamação/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Macrófagos/metabolismo , Masculino , Camundongos , Fosforilação , Extratos Vegetais/isolamento & purificação , Células RAW 264.7 , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Xilenos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
18.
Nat Prod Bioprospect ; 10(4): 227-241, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32519306

RESUMO

Melodinus henryi is a good source of terpenoid indole alkaloids, and traditionally used as a folk medicine in the treatment of meningitis and fracture. In order to further exploit their potential uses, its anti-inflammatory and immunosuppressive activities, safety evaluations and chemical profiles have been illustrated. Compared to the crude methanol extract from M. henryi and its non-alkaloidal fraction, the total alkaloidal fraction (MHTA) had the strongest anti-inflammatory and immunosuppressive activities. In the acute oral toxicity assay, the half lethal dose (LD50) of MHTA was more than 2000 mg/kg. The sub-acute toxicity assay for consecutive 28 days exhibited MHTA at a lower concentrations of less than 500 mg/kg might be regarded as safe, and might damage spleen, liver, kidney, and heart when the dose is higher than 1000 mg/kg. In addition, a phytochemical investigation on MHTA led to the isolation of 15 monoterpenoid indole alkaloids. Thus, in regard with the potent side effects of MHTA, it should be used with caution in the development of phytomedicine.

19.
Chem Commun (Camb) ; 56(31): 4288-4291, 2020 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-32182314

RESUMO

The tough challenges for the sensitive and accurate detection of circulating miRNAs (cmiRNAs) in the peripheral blood are low abundance, and high interference from environmental or background factors or other molecules. Here, we developed a double-signal mode based on metal-organic framework coupled cascaded nucleic acid circuits for the accurate and sensitive detection of serum circulating miRNAs.


Assuntos
Técnicas Biossensoriais/métodos , MicroRNA Circulante/sangue , Sondas de DNA/química , DNA/química , Estruturas Metalorgânicas/química , MicroRNA Circulante/genética , DNA/genética , Sondas de DNA/genética , Corantes Fluorescentes/química , Glucose Oxidase/química , Humanos , Peróxido de Hidrogênio/química , Limite de Detecção , MicroRNAs/sangue , MicroRNAs/genética , Hibridização de Ácido Nucleico , Oxirredução , Fenazinas/química , Fenilenodiaminas/química , Espectrometria de Fluorescência/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...