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1.
Mikrochim Acta ; 191(6): 338, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38780645

RESUMO

A novel electrochemical sensor, MIP/Cu-MOF/rGO/AuNPs/GCE, was developed by depositing gold nanoparticles, coating Cu-MOF/GO on the surface of glassy carbon electrode (GCE) before electroreducing graphene oxide (GO) to rGO and covering molecularly imprinted membrane by electropolymerization for highly sensitive detection of electroneutral organophosphorus pesticide residues in agricultural product. Cyclic voltammetry, differential pulse voltametry, scanning electron microscopy, energy-dispersive spectroscopy, and atomic force microscopy were used to characterize the imprinted sensor. Several key factors such as chitosan concentration, suspension volume, pH of polymerization solution, and polymerization scanning rate during preparation of the imprinted sensor were optimized in detail. When electroneutral phosmet was used as a template, the linear range of MIP/Cu-MOF/rGO/AuNPs/GCE for detecting phosmet was 1.00 × 10-14-5.00 × 10-7 mol/L with the limit of detection of 7.20 × 10-15 mol/L at working potentials of - 0.2 to 0.6 V. The selectivity, reproducibility, and repeatability of MIP/Cu-MOF/rGO/AuNPs/GCE were all acceptable. The recoveries of this method for determining phosmet in real samples ranged from 94.2 to 106.5%. The MIP/Cu-MOF/rGO/AuNPs/GCE sensor could be applied to detect electroneutral pesticide residues in organisms and agricultural products.

2.
J Environ Manage ; 370: 122873, 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39405855

RESUMO

The persistence and stability of refractory organic compounds such as dyes in water bodies cause serious toxicity to humans. The present study provides an in-depth investigation into the evolution law of electro-Fenton (EF) oxidation to in situ electrocoagulation (EC) process and its mechanism for highly efficient removal of refractory organic pollutants. A comprehensive evaluation of the energy efficiency by EC, EF (constant pH = 3) and electrocatalytic oxidation (EO) processes under the same research levels was conducted. The results showed that in the EF-EC mode, the removal efficiency of Rhodamine B (RhB) was enhanced by 33.41% compared to the EC system. Additionally, electrode consumption is 52.9% of the EF system, and current efficiency was improved by 272.98% compared to the EO system. Hydroxyl radical (·OH) and polynuclear species (Fe(b)) are the main species to remove refractory organics and intermediates. Unlike the synergistic effect of ·OH homogeneous oxidation and electrocoagulation in the EF-EC process, the ·OH produced in the EO process mainly undergoes heterogeneous oxidation at the electrode interface. The formed iron oxides were mainly Fe2O3 and ɑ-FeOOH. Density functional theory calculations and liquid chromatograph-mass spectrometer analysis indicated that the degradation of RhB mainly included deethylation, deamination, degradation, ring-opening and mineralization reactions. This study provides a valuable reference for related research in the field of environmental electrochemical remediation.

3.
Int J Mol Sci ; 23(21)2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36361874

RESUMO

To produce antioxidant substances from agricultural waste Camellia spp. fruit shells before their further utilization, gallic acid from five kinds of Camellia spp. fruit shells was separated on specific recognition by deep eutectic solvent molecularly imprinted polymers (DES@MIPs), which were prepared by bulk polymerization using gallic acid as the template and deep eutectic solvents (α-methylacrylic acid and choline chloride) as functional monomers. The optimized DES@MIPs were characterized by scanning electron microscopy, particle size analysis, nitrogen sorption porosimetry, elemental analysis, Fourier transform infrared spectroscopy, and thermal gravimetric analysis. The adsorptive behavior of gallic acid on DES@MIPs was also investigated. The results indicated that DES@MIPs were successfully prepared as mesoporous materials with average pore diameter of 9.65 nm and total pore volume of 0.315 cm3 g-1, and the adsorption behavior was multilayer adsorption and pseudo-second-order kinetics with the saturation adsorptive capacity of gallic acid reaching 0.7110 mmol g-1. Although the content of gallic acid in five fruit shells was quite different, the purification recovery of gallic acid was high, ranging from 87.85-96.75% with a purity over 80%. Thus, the purification of gallic acid from Camellia spp. fruit shells could be realized feasibly using DES@MIPs with favorable economic and environmental benefits.


Assuntos
Camellia , Impressão Molecular , Impressão Molecular/métodos , Polímeros Molecularmente Impressos , Ácido Gálico , Frutas , Polímeros/química , Solventes/química , Adsorção
4.
Anal Bioanal Chem ; 413(3): 935-943, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33210176

RESUMO

The synthesis of fascinating multifunctional carbon dots (CDs) attracted immense attention. Here, a facile solvothermal treatment of red pitaya peels in acetic acid produced CDs (designated as ACDs, excitation/emission wavelengths at 357/432 nm). ACDs with high sp2-hybridized carbon and carboxylic group contents can rapidly and selectively reduce Au3+ to Au0, and stabilize produced Au nanoparticles (AuNPs). The synergetic effect of electron transfer from ACDs to Au3+ and inner filter effect (IFE) from ACDs to AuNPs quenches the fluorescence within 30 s. Simultaneously, the resulting AuNPs have a purple color with a maximum absorption at 545 nm for visual detection. Therefore, for the first time, we reported a fluorometric and colorimetric dual-mode sensing system for real-time, highly sensitive and selective detection of Au3+. The fluorescence quenching ratio and absorbance change linearly with the increase of Au3+ concentration in the range of 0.3-8.0 µM and 3.3-60.0 µM with limits of detection (LODs) at 0.072 µM and 2.2 µM, respectively. The assay was applied for Au3+ determination in spiked real water samples with recoveries from 95.5 to 105.0%, and relative standard deviation (RSD) of less than 6.5%. Furthermore, ACDs with good photostability, low cytotoxicity, and excellent biocompatibility were successfully applied for intracellular Au3+ sensing and imaging. In addition, ACDs exhibited an extraordinarily high antioxidant activity, with an IC50 value for DPPH radical scavenging (0.70 µg mL-1) much lower than that of ascorbic acid (4.34 µg mL-1). The proposed strategy demonstrates the outstanding properties of ACDs in chemical and biomedical analysis. Graphical abstract.


Assuntos
Antioxidantes/farmacologia , Cactaceae/química , Carbono/química , Colorimetria/métodos , Fluorometria/métodos , Ouro/análise , Pontos Quânticos/química , Células HeLa , Humanos , Limite de Detecção , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Análise Espectral/métodos , Difração de Raios X
5.
Mikrochim Acta ; 186(12): 791, 2019 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-31734753

RESUMO

Red-emissive carbon dots (CDs) were synthesized by one-step hydrothermal technique using citric acid (CA), and urea in N,N-dimethylformamide (DMF) solution. The CDs has an average diameter of 2.3 nm, excitation/emission maxima at 553/606 nm, and a low photoluminescence quantum yield (4%). Fluorescence is weakly quenched by the ions Fe3+, Hg2+, Cu2+, Co2+, Zn2+, Ca2+, Ni2+, and Pb2+. After addition of cetyltrimethyl ammonium ion (CTAB), electrostatic interaction between negatively charged CDs and CTAB causes the CDs to self-aggregate. The formation of CD/CTAB increases the average particle diameter to around 13 nm and enhances the quantum yield to 24%. The hydrophobic segments of CTAB twined into a network structure can selectively trap Fe3+ and then interact with surface groups of the CDs to cause quenching. The CD/CTAB nanoprobe enables fluorometric determination of Fe3+ with a linear response in the 0.10-10 µM concentration range and a 0.03 µM limit of detection. The probe was utilized for determination of Fe3+ in human serum samples, and satisfactory results were obtained. Graphical abstractSchematic representation of fluorometric analysis of Fe(III) ion by cetyltrimethyl ammonium ion (CTAB) mediated red emission carbon dots (CDs). The hydrophobic segments of CTAB twined into a network structure can selectively trap Fe(III) and then interact with surface groups of the CDs to cause quenching.

6.
Molecules ; 23(6)2018 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-29899218

RESUMO

The overuse of cartap in tea tree leads to hazardous residues threatening human health. A colorimetric determination was established to detect cartap residues in tea beverages by silver nanoparticles (AgNP) sensor with magnetic molecularly imprinted polymeric microspheres (Fe3O4@mSiO2@MIPs) as recognition elements. Using Fe3O4 as supporting core, mesoporous SiO2 as intermediate shell, methylacrylic acid as functional monomer, and cartap as template, Fe3O4@mSiO2@MIPs were prepared to selectively and magnetically separate cartap from tea solution before colorimetric determination by AgNP sensors. The core-shell Fe3O4@mSiO2@MIPs were also characterized by FT-IR, TEM, VSM, and experimental adsorption. The Fe3O4@mSiO2@MIPs could be rapidly separated by an external magnet in 10 s with good reusability (maintained 95.2% through 10 cycles). The adsorption process of cartap on Fe3O4@mSiO2@MIPs conformed to Langmuir adsorption isotherm with maximum adsorption capacity at 0.257 mmol/g and short equilibrium time of 30 min at 298 K. The AgNP colorimetric method semi-quantified cartap ≥5 mg/L by naked eye and quantified cartap 0.1⁻5 mg/L with LOD 0.01 mg/L by UV-vis spectroscopy. The AgNP colorimetric detection after pretreatment with Fe3O4@mSiO2@MIPs could be successfully utilized to recognize and detect cartap residues in tea beverages.


Assuntos
Impressão Molecular/métodos , Prata/química , Chá/química , Tiocarbamatos/análise , Colorimetria , Óxido Ferroso-Férrico/química , Nanopartículas Metálicas , Microesferas , Estrutura Molecular , Dióxido de Silício/química , Tiocarbamatos/efeitos adversos
7.
Molecules ; 19(8): 11487-504, 2014 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-25093987

RESUMO

Corydalis Rhizoma is the dried tuber of Corydalis yanhusuo W.T. Wang which is used in traditional Chinese medicine for pain relief and blood activation. Before being used in the clinics, C. yanhusuo is traditionally processed through dry-frying or frying with vinegar, wine or salt. In this study, eleven alkaloids from Corydalis Rhizoma, namely protopine (1), α-allocryptopine (2), tetrahydrocolumbamine (3), coptisine (4), palmatine (5), berberine (6), dehydrocorydaline (7), D,L-tetrahydropalmatine (8), tetrahydroberberine (9), corydaline (10) and tetrahydrocoptisine (11) were simultaneously quantified using a newly developed high performance liquid chromatography-diode array detector (HPLC-DAD) method. The influence of vinegar and wine processing on the content of the main alkaloids of Corydalis Rhizoma was investigated. For this purpose, two common formulations with clinical application, namely the water decoction of Corydalis Rhizoma and its formula Jin Ling Zi San (combination of Corydalis Rhizoma and Toosendan Fructus) were studied. In the two water decoctions, wine and vinegar processing increased the amount of tertiary alkaloids. The differences were more pronounced for Jin Ling Zi San, in which case the content of all tertiary alkaloids (compounds 1, 2, 3, 8, 9, 10, 11) was increased by wine processing.


Assuntos
Ácido Acético/química , Alcaloides/química , Corydalis/química , Extratos Vegetais/química , Vinho , Medicamentos de Ervas Chinesas/química , Medicina Tradicional Chinesa , Metabolômica/métodos , Estrutura Molecular , Reprodutibilidade dos Testes , Solventes
8.
Zhongguo Zhong Yao Za Zhi ; 39(4): 689-94, 2014 Feb.
Artigo em Zh | MEDLINE | ID: mdl-25204148

RESUMO

Lycii Cortex, a popular herb medicine in traditional Chinese medicine, is used to treat different inflammation-related diseases. The aim of our work is to find the key constituents inhibiting NF-kappaB, a key regulator of inflammation. In the investigations of cell-based in vitro assays of extracts, we found that both ethyl acetate extract and methanol extract of Lycii Cortex inhibited the TNF-alpha-induced activation of NF-kappaB. Through bioassay-guided fractionation, we identified 4 phenolic amides including trans-N-(p-coumaroyl) tyramine (1), trans-N-feruloyltyramine (2), trans-N-caffeoyltyramine (3), and dihydro-N-caffeoyltyramine (4). Four phenolic amides showed differently inhibitory activities on TNF-alpha-induced NF-kappaB activation. Trans-N-caffeoyltyramine (3) was identified as the key component with an IC50 of 18.41 micromol x L(-1). It was suggested that the hydroxyl group at C-3 in trans-N-caffeoyltyramine might be a key binding site and its C-7,8-double bond might play an important role on NF-kappaB inhibitory activities as the link of the conjugation of pi electrons leading to a partial planar conformation. It might be inferred that the biological activity of compound 3 is attributed to the structure of Michael reaction acceptor containing alpha, beta-unsaturated ketones and benzene along with hydroxyl group in o-diphenol.


Assuntos
Medicamentos de Ervas Chinesas/química , Mediadores da Inflamação/antagonistas & inibidores , Lycium/química , NF-kappa B/antagonistas & inibidores , Bioensaio , Linhagem Celular , Medicamentos de Ervas Chinesas/isolamento & purificação , Medicamentos de Ervas Chinesas/farmacologia , Humanos , Mediadores da Inflamação/imunologia , Estrutura Molecular , NF-kappa B/imunologia
9.
Nat Prod Res ; : 1-17, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38899590

RESUMO

Camellia oleifera (C. oleifera) is a woody oil plant with a good reputation of 'Oriental Olive Oil' in China. The national understanding of the health-care benefits of Camellia oil are already widespread, but the production of C. oleifera fruit has not been achieved large-scale industrialisation. In this review, we focus on the properties and commercial value of its natural products, and processing technology, performance characterisation, and novel modification strategies of its processed products. In addition, we briefly summarised the research progress of breeding and put forward the comprehensive utilisation of C. oleifera fruit based on the tandem of extraction and processing. This review might attract more researchers to make profound study regarding it as an alternative of olive oil.

10.
Nat Prod Res ; : 1-8, 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39319415

RESUMO

Macleaya cordata is a traditional herb medicine with alkaloids as the main bioactive substance. To identify alkaloid compounds from M. cordata, its crude extract was obtained with 0.2 mol/L hydrochloric acid, and alkaloid compounds in the demineralised extract by organic solvents from crude extract were qualitatively and quantitatively analysed by UPLC-DAD-QTOF-MS/MS. Through systematic analysis of retention times, mass spectrometry data, and diagnostic fragmentation pathways and rules, 32 alkaloids were rapidly unambiguously identified or tentatively deduced by comparison with standard MS spectra or literature data. Among them, 16 minor -alkaloid compounds including nandazurine, hydroxychelidonine, capauridine, (-)-dicentrine, leptopine, adlumidine, takatonine, (2, 3)-trans-N-(p-hydroxyphenethyl)ferulamide, 9-ethoxyaristololactam, thalicminine, cassythidine, acetylisocorynoline, oxynitidine, crinasiatine, zanthoxyline, and 7,9-dimethoxy-2,3-methylendioxybenzophenanthridine were found in M. cordata for the first time. The abundant alkaloids might be responsible for the bioactivity of M. cordata, which laid a foundation for the study of quality control, livestock, and clinical applications of M. cordata.

11.
Biosens Bioelectron ; 222: 114981, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36473422

RESUMO

With the increasing concerns of food safety and environmental protection, it is desirable to develop reliable, effective, and portable sensors for detection of organophosphorus pesticides (OPs). Here, a cascade reaction system integrated with threaded 3D microfluidic paper analytical device (3D µPAD) was firstly developed for background-free and visual detection of OPs in agricultural samples. Butyrylcholinesterase (BChE) hydrolyzed acetylcholine into thiocholine (TCh), which reduced MnO2 nanosheets into Mn2+. With addition of OPs, BChE activity was irreversibly inhibited, and the generation of TCh and the reduction of MnO2 nanosheets were prevented. Then the remaining MnO2 nanosheets oxidized o-phenylenediamine into 2,3-diaminophenazine with yellow-emission fluorescence, which quenched the fluorescence intensity of red-emission carbon dots (RCDs) via inner-filter effect. Based on above mechanism, a ratiometric fluorescent system was established for OPs detection. Threaded 3D µPAD consisted of 4 layers, which allowed to load and/or add reagents to trigger the cascade reaction system for OPs detection. The fluorescent images presented distinguishable color variations from red to yellow with dichlorvos concentrations ranging from 2.5 to 120 µg L-1, and the limit of detection was 1.0 µg L-1. In the practical samples testing, threaded 3D µPAD can eliminate background influence on fluorescent signal for OPs detection. Threaded 3D µPAD integrated with ratiometric sensing platform has merits of accuracy response, facile operation, and background-free detection, which supplies a new alternative approach for on-site pesticide detection.


Assuntos
Técnicas Biossensoriais , Praguicidas , Compostos Organofosforados , Butirilcolinesterase , Microfluídica , Compostos de Manganês , Óxidos , Técnicas Biossensoriais/métodos , Corantes Fluorescentes
12.
Polymers (Basel) ; 14(1)2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-35012196

RESUMO

Gallic acid is widely used in the field of food and medicine due to its diversified bioactivities. The extraction method with higher specificity and efficiency is the key to separate and purify gallic acid from complex biological matrix. Herein, using self-made core-shell magnetic molecularly imprinted polymers (MMIP) with gallic acid as template, a hollow magnetic molecularly imprinted polymer (HMMIP) with double imprinting/adsorption surfaces was prepared by etching the mesoporous silica intermediate layer of MMIP. The characterization and adsorption research showed that the HMMIP had larger specific surface area, higher magnetic response strength and a more stable structure, and the selectivity and saturated adsorption capacity (2.815 mmol/g at 318 K) of gallic acid on HMMIP were better than those of MMIP. Thus, in addition to MMIP, the improved HMMIP had excellent separation and purification ability to selectively extract gallic acid from complex matrix with higher specificity and efficiency.

13.
Antonie Van Leeuwenhoek ; 99(4): 807-15, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21287404

RESUMO

Angucyclines are aromatic polyketides with antimicrobial, antitumor, antiviral and enzyme inhibition activities. In this study, a new pair of degenerate primers targeting the cyclase genes that are involved in the aromatization of the first and/or second ring of angucycline, were designed and evaluated in a PCR protocol targeting the jadomycin cyclase gene of Streptomyces venezuelae ISP5230. The identity of the target amplicon was confirmed by sequencing. After validation, the primers were used to screen 49 actinomycete isolates from three different marine sponges to identify putative angucycline producers. Seven isolates were positively identified using this method. Sequence analysis of the positive amplicons confirmed their identity as putative angucycline cyclases with sequence highly similar to known angucycline cyclases. Phylogenetic analysis clustered these positives into the angucycline group of cyclases. Furthermore, amplifications of the seven isolates using ketosynthase-specific primers were positive, backing the results using the cyclase primers. Together these results provided strong support for the presence of angucycline biosynthetic genes in these isolates. The specific primer set targeting the cyclase can be used to identify putative angucycline producers among marine actinobacteria, and aid in the discovery of novel angucyclines.


Assuntos
Actinobacteria/enzimologia , Antibacterianos/biossíntese , Benzo(a)Antracenos/metabolismo , Poríferos/microbiologia , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Animais , Descoberta de Drogas , Macrolídeos , Filogenia , Policetídeo Sintases/biossíntese , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Streptomyces/classificação , Streptomyces/enzimologia , Streptomyces/metabolismo
14.
Food Chem ; 344: 128651, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33243557

RESUMO

Buddleja Flos is used as yellow rice colorant and a well-known traditional Chinese medicine. But its biochemical profiling is still lack due to complex matrix. Here, ultrafiltration high-performance liquid chromatograph-quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) with diagnostic ions filtering strategy was proposed for rapid and comprehensive investigation of its α-glucosidase inhibitors. As a result, 33 bioactive compounds (13 phenylethanoid glycosides and 20 flavonoids) were successfully screened and identified. In addition, α-glucosidase inhibitory activities of twenty-two references were verified. Six flavonoid aglycones (4, 28, and 30-33) showed excellent α-glucosidase inhibitory activities (IC50, from 5.11 ± 0.85 to 32.49 ± 9.76 µg/mL), much higher than that of acarbose (IC50, 195.49 ± 10.05 µg/mL). Five flavonoid-monoglycosides (7, 12, 13, 20, and 22) presented moderate inhibitory activities with IC50 from 160.98 ± 23.19 to 249.37 ± 35.83 µg/mL. Results showcased the high efficiency of proposed strategy in profiling of bioactive compounds from natural products.


Assuntos
Buddleja/química , Cromatografia Líquida de Alta Pressão/métodos , Inibidores de Glicosídeo Hidrolases/análise , Inibidores de Glicosídeo Hidrolases/isolamento & purificação , Espectrometria de Massas em Tandem/métodos , Ultrafiltração/métodos
15.
RSC Adv ; 12(2): 777-784, 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-35425150

RESUMO

Hypochlorous acid (HClO) is a special kind of reactive oxygen species, which plays an important role in resisting pathogen invasion and maintaining cell redox balance and other physiological processes. In addition, HClO is commonly used in daily life as a bleaching and disinfectant agent. Its excessive use can also lead to death of water animals and serious respiratory and skin diseases in humans. Therefore, it is of great significance to develop a quick and convenient tool for detecting HClO in the environment and organisms. In this paper, we utilize the specific reaction of HClO with dimethylthiocarbamate to develop a novel naphthalene derivative fluorescent probe (BNA-HClO), it was designed and synthesized by using 6-(2-benzothiazolyl)-2-naphthol as the fluorophore and N,N-dimethylthiocarbamate as the recognition group. BNA-HClO shows large fluorescence enhancement (374-fold), high sensitivity (a detection limit of 37.56 nM), rapid response (<30 s), strong anti-interference ability and good specificity in vitro. Based on the outstanding in vitro sensing capability of BNA-HClO, it has been successfully used to detect spiked HClO in tap water, medical wastewater and fetal bovine serum with good recovery. BNA-HClO has also been successfully used as a portable test strip for the in situ semi-quantitative detection of HClO in tap water solutions. In addition, BNA-HClO can successfully enable the detection and imaging of exogenous and endogenous HClO in living cells. This work provides a simple and effective tool for the detection and imaging of HClO in environmental and biological systems, and provides some theoretical guidance for future exploration of biological and pathological studies related to HClO.

16.
Food Chem ; 315: 126171, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31991253

RESUMO

A new-style white pepper derived dual-emission carbon dots (CDs) with a quantum yield of 10.4% was designed and facile constructed with one-pot solvothermal method. The green emission (520 nm) had an efficient and special "turn-on" fluorescence sensing of coenzyme A (CoA) with the aid of Cu2+, while red emission (668 nm) barely changed and worked as reference. In the concentration range (0-150 µM), relative fluorescence intensity ratios (F520/F668) showed excellent linear correlation with concentrations of CoA, and detection limit was as low as 8.75 nm. Moreover, the strategy has been successfully applied for label-free detection of CoA in real pig liver samples with good recoveries (93.3-108.0%). Notably, the synthesized CDs had durable fluorescence, low cytotoxicity, and good biocompatibility for cellular imaging, which demonstrated wide and promising applicability for biosensing and bioimaging in the future.


Assuntos
Carbono/química , Coenzima A/análise , Imagem Molecular/métodos , Piper nigrum/química , Pontos Quânticos/química , Animais , Fluorescência , Química Verde , Células HeLa , Humanos , Limite de Detecção , Fígado/química , Imagem Molecular/instrumentação , Pontos Quânticos/toxicidade , Suínos , Testes de Toxicidade
17.
Food Chem ; 312: 126042, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31911351

RESUMO

Although mango leaves are the main ingredients in some traditional Chinese medicine preparations and folk tea, they with considerable quantities are usually discarded as agricultural waste. Thus, to extend their potential, reverse ultrafiltration-HPLC-DAD-QTOF-MS/MS combining with key ion filtering strategy was proposed to efficiently fish and systematically identify tyrosinase inhibitors in ethyl acetate fraction of mango leaves, which has the highest total phenolic content (40.00 ± 0.84 mg GAE/g DW) and tyrosinase inhibition activity (IC50, 17.62 ± 1.26 µg/mL). Finally, 36 polyphenolic tyrosinase inhibitors were unambiguously characterized or tentatively identified, and three of them were found in mango leaves for the first time. Results suggested that the proposed strategy was powerful for effective identification of bioactive compounds in complex mixtures (e.g. food, agricultural and sideline products), and the findings would lay a foundation for potential applications of mango leaves in pharmaceutical, cosmetic, and food industrial fields.


Assuntos
Inibidores Enzimáticos/farmacologia , Mangifera/química , Monofenol Mono-Oxigenase/antagonistas & inibidores , Cromatografia Líquida de Alta Pressão , Fenóis/análise , Folhas de Planta/química , Espectrometria de Massas em Tandem
18.
Wei Sheng Wu Xue Bao ; 49(12): 1555-63, 2009 Dec.
Artigo em Zh | MEDLINE | ID: mdl-20222438

RESUMO

Polyketides have played an important role in antibiotic drug discovery with most antibacterial drugs being derived from a natural product or natural product lead. Furthermore, the biosynthetic gene clusters for numerous bioactive polyketides have been intensively studied over the past 15 years. This paper focuses on the polyketide drugs approved by US-FDA and takes a general view in the antibiotics produced by polyketide synthase in streptomyces.


Assuntos
Antibacterianos/metabolismo , Proteínas de Bactérias/metabolismo , Macrolídeos/metabolismo , Policetídeo Sintases/metabolismo , Streptomyces/metabolismo , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Macrolídeos/química , Macrolídeos/farmacologia , Dados de Sequência Molecular , Policetídeo Sintases/genética , Streptomyces/química , Streptomyces/enzimologia , Streptomyces/genética
19.
Polymers (Basel) ; 11(11)2019 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-31717892

RESUMO

The rapid detection of organophosphorus pesticide residues in food is crucial to food safety. One type of novel, magnetic, molecularly-imprinted polymeric microsphere (MMIP) was prepared with vinyl phosphate and 1-octadecene as a collection of dual functional monomers, which were screened by Gaussian09W molecular simulation. MMIPs were used to enrich organic phosphorus, which then detected by fluorescence quenching in vinyl phosphate-modified carbon dots (CDs@VPA) originated from anhydrous citric acid. MMIPs and CDs@VPA were characterized by TEM, particle size analysis, FT-IR, VSM, XPS, adsorption experiments, and fluorescence spectrophotometry in turn. Through the fitting data from experiment and Gaussian quantum chemical calculations, the molecular recognition properties and the mechanism of fluorescence detection between organophosphorus pesticides and CDs@VPA were also investigated. The results indicated that the MMIPs could specifically recognize and enrich triazophos with the saturated adsorption capacity 0.226 mmol g-1, the imprinting factor 4.59, and the limit of recognition as low as 0.0006 mmol L-1. Under optimal conditions, the CDs@VPA sensor has shown an extensive fluorescence property with a LOD of 0.0015 mmol L-1 and the linear range from 0.0035 mmol L-1 to 0.20 mmol L-1 (R2 = 0.9988) at 390 nm. The mechanism of fluorescence detection of organic phosphorus with CDs@VPA sensor might be attributable to hydrogen bonds formed between heteroatom O, N, S, or P, and the O-H group, which led to fluorescent quenching. Meanwhile, HN-C=O and Si-O groups in CDs@VPA system might contribute to cause excellent blue photoluminescence. The fluorescence sensor was thorough successfully employed to the detection of triazophos in cucumber samples, illustrating its tremendous value towards food sample analysis in complex matrix.

20.
Food Chem ; 179: 206-12, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-25722156

RESUMO

Hydrophilic molecularly imprinted polymers (MIPs) for gallic acid (GA) were prepared with excellent recognition ability in an aqueous solution. The proposed MIPs were designed by self-polymerization of dopamine (DA) on magnetic mesoporous silica (Fe3O4@SiO2@mSiO2, MMS) using GA as template. Resulting Fe3O4@SiO2@mSiO2@MIPs (MMS-MIPs) were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), vibrating sample magnetometer (VSM), and evaluated by adsorption isotherms/kinetics and competitive adsorption. The adsorption behavior between GA and MMS-MIPs followed Langmuir and Sips adsorption isotherms with a maximum adsorption capacity at 88.7 mg/g and pseudo-second-order reaction kinetics with fast binding (equilibrium time at 100 min). In addition, MMS-MIPs showed rapid magnetic separation (10 s) and stability (retained 95.2% after six cycles). Subsequently, MMS-MIPs were applied for the selective extraction and determination of GA from grape, apple, peach and orange juices (4.02, 3.91, 5.97, and 0.67 µg/g, respectively). Generally, the described method may pave the way towards rationally designing more advanced hydrophilic MIPs.


Assuntos
Bebidas/análise , Frutas/química , Ácido Gálico/análise , Impressão Molecular , Dióxido de Silício/química , Adsorção , Ácido Gálico/química , Interações Hidrofóbicas e Hidrofílicas , Microesferas , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier
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