Determination of catechin in green tea using a catechol oxidase biomimetic sensor

Fernandes, Suellen Cadorin; Osório, Renata El-Hage Meyer de Barros; Anjos, Ademir dos; Neves, Ademir; Micke, Gustavo Amadeu; Vieira, Iolanda Cruz

doi:10.1590/s0103-50532008000600024

Cited by 28 publications

(29 citation statements)

References 27 publications

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“…Os métodos tradicionais para a detecção de catequinas incluem cromatografia líquida de alta eficiência (HPLC) [1,16,17] combinada com quimiluminescência [18,19], espectrofotometria [2], eletroquímica [3,[20][21][22][23][24][25][26], UV e detecção fluorimétrica [27].…”

Section: Introductionunclassified

Determinação de catequinas por eletrodo de carbono impresso modificado com nanotubo de carbono funcionalizado

Silva

Kubota

et al. 2016

Eclet. Quim.

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____________________________________________________________________________Resumo: A Catequina é um composto fenólico com grande potencial oxidante, encontrada em diversos tipos de alimentos, dentre alguns dos benefícios da catequina estão o fortalecimento capilar, melhoria do fluxo sanguíneo, redução dos níveis de colesterol. Neste artigo, utilizou-se da técnica de voltametria cíclica (VC) para otimizar o eletrodo de carbono impresso modificado com nanotubo de carbono funcionalizado para detectar e quantificar catequina por meio da técnica de voltametria de onda quadrada (VOQ). Para este eletrodo, os melhores resultados foram obtidos a uma concentração de 1x10 -3 mol L -1 de catequina em meio de tampão fosfato 0,1 mol L -1 pH 7,0 a uma velocidade de varredura de potencial de 0,05 V s -1 . A partir destas condições foi obtida uma curva analítica com comportamento linear no intervalo de concentração de catequina entre 2,0x10 -7 a 1,68x10, com limites de detecção e de quantificação de 9,2x10 -8 e 3,0x10 -7 mol L -1, respectivamente por VOQ. Este eletrodo apresentou boa repetibilidade com um desvio de padrão relativo de 4,05%. A oxidação da catequina apresentou um pico localizado em torno de 0,15V vs Ag/AgCl, estando próximo dos potenciais de pico mostrados na literatura.Palavras-chave: catequina, eletrodo de carbono impresso, nanotubo de carbono, sensor eletroquímico ____________________________________________________________________________ Abstract: Catechin is a phenolic compound with high oxidizing potential, found in several types of foods, some of the benefits of catechins are capillary strengthening, improvement of blood flow and reduction of cholesterol levels. In this paper, it was used the cyclic voltammetry technique (CV) to optimize the printed carbon electrode modified with carbon nanotube, functionalized to detect and quantify catechin by means of the squarewave voltammetry technique (SWV). For this electrode, the best results were obtained at a catechin concentration of 1x10 -3 mol L -1 in means of 0.1 mol L -1 phosphate buffer pH 7.0 at a potential scan rate of 0.05 V s -1 . From these conditions, an analytical curve was obtained with a linear behavior in the catechin concentration range of 1,68x10 -5 to 2,0x10 -7 mol L -1, with limits of detection and quantification of 9,2x10 -8 and 3,0x10 -7 mol L -1 , respectively, by SWV. This electrode showed good repeatability with a standard deviation of 4.05%. Oxidation of catechin showed a peak located around 0,15V vs Ag / AgCl, being close to the peak potentials shown in the literature.

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Section: Introductionunclassified

Determinação de catequinas por eletrodo de carbono impresso modificado com nanotubo de carbono funcionalizado

Silva

Kubota

et al. 2016

Eclet. Quim.

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“…Reactions between oxidized polyphenols and proteins are thought to be partly responsible for the so called enzymatic browning in plants [4,5]. Catechol is also used in a variety of applications such as a reagent for photography, dyeing fur, rubber and plastic production, pesticides and in pharmaceutical industries [6]. Recent epidemiological studies have shown that the consumption of tea prevent cancer in humans because the tea leaf contains abundant groups of polyphenols [7].…”

Section: Introductionmentioning

confidence: 99%

“…Even at low concentration in foods and cigarette smokes, catechol may cause mutagenesis and cancerous alterations [8,9]. Many different reactions can occur with biomolecules such as DNA, proteins and membranes, ultimately leading to non repairable damage [6].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical determination of catechol in tea samples using anthraquinone modified carbon paste electrode

Melak¹,

Redi²,

Tessema³

et al. 2013

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Electrochemical investigation of catechol using square wave voltammetry with anthraquinone modified carbon paste electrode was found to be very sensitive. Compared with the unmodified carbon paste electrode, the anthraquinone modified electrode remarkably increases the peak currents of catechol, and greatly lowers the peak potential separation. Two varieties of tea, namely green, and black variety: Wush Wush tea, from Ethiopia, known by its brand name were investigated. Responses for the extracts using ethanol: water (1:4) % v/v showed green tea to be superior in catechol content. Optimization of different variables such as pH of working solution, modifier composition and square wave parameters such as frequency, amplitude and step potential were made to improve the method efficiency during the experiment. The reproducibility for the nine repeated analysis of 80 μmol·L .

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“…15 The catecholase activity has been determined in vitro for many mononuclear and dinuclear copper(II) complexes. Specialized research groups have developed μ-hidroxo, μ-carboxylato or μ-imidazole dinuclear copper(II) compounds with the aim of mimicking the active site of the catechol oxidase enzyme, [12][13][14][15][18][19][20][21][22][23][24][25][26][27][28][29] and the mechanism of the catalytic cycle has been proposed for some complexes. Catecholase activity has been also determined for a few mononuclear and dinuclear copper(II)-NSAIDs complexes, [30][31][32] but the mechanism of the catalytic oxidation remains unclear.…”

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confidence: 99%

Significant anti-inflammatory properties of a copper(II) fenoprofenate complex compared with its parent drug: Physical and chemical characterization of the complex

Agotegaray¹,

Boeris²,

Quinzani³

2010

J. Braz. Chem. Soc.

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A síntese, a caracterização físico-química, as propriedades anti-inflamatórias e a atividade mimética de catecolase do complexo de cobre(II) com a droga anti-inflamatória non-esteroidal Fenoprofeno [ácido 2-(3-fenóxifenil)propiônico] com fórmula [Cu 2 (fen) 2 (dmf) 2 ] (fen = ânion do fenoprofenato, dmf = N,N-dimetilformamida) foram investigadas. Os resultados da análise espectroscópica (espectros de FTIR e EPR) e dados de análise termogravimétrica e térmica diferencial obtidos para o complexo sólido estão de acordo com a sua estrutura dinuclear. Os espectros eletrônicos do produto são igualmente apresentados e discutidos neste trabalho. O complexo foi testado para as suas propriedades anti-inflamatórias em comparação com a droga de referência, o sal de cálcio do Fenoprofeno. A administração oral do composto binuclear inibiu o desenvolvimento do edema induzido por carragenana em ratos; esta inibição foi mais significativa do que a obtida com a droga de referência. O estudo cinético da atividade mimética da catecolase foi realizado espectrofotometricamente, monitorando-se a transformação oxidativa do 3,5-di-terc-butilcatecol na o-quinona correspondente. Os parâmetros cinéticos foram determinados pelo emprego do modelo de Michaelis-Menten, que demonstrou que o novo complexo mimetiza a atividade da catecol oxidase.The synthesis, physicochemical characterization, anti-inflammatory properties and catecholase mimetic activity of the dinuclear complex of copper(II) with the non-steroidal anti-inflammatory drug Fenoprofen [2-(3-phenoxyphenyl)propionic acid] with formula [Cu 2 (fen) 4 (dmf) 2 ] (fen = fenoprofenate anion, dmf = N,N-dimethylformamide) have been investigated. Results of spectroscopic analysis (FTIR and EPR) as well as thermogravimetric and differential thermal analysis data obtained for the solid complex are in good agreement with its dinuclear structure. Electronic spectra of the product are also reported and discussed. The complex was tested for anti-inflammatory properties in comparison to the parent drug, Fenoprofen calcium salt. Oral administration of the dinuclear compound inhibited development of carrageenan-induced oedema in mice; this inhibition was higher than that observed for the parent drug. The kinetic study of the catecholase mimetic activity was carried out spectrophotometrically by monitoring the oxidative transformation of 3,5-di-tert-butylcatechol into the corresponding light-absorbing o-quinone. Kinetic parameters were determined employing the Michaelis-Menten model, showing that the new complex presents catechol oxidase mimetic activity.Keywords: copper(II), Fenoprofen, anti-inflammatory properties, catecholase activity IntroductionThe proposed curative properties of copper(II) carboxylate-based non-steroidal anti-inflammatory drugs (NSAIDs) have led to the development of numerous mononuclear and dinuclear copper(II) complexes of NSAIDs with enhanced anti-inflammatory activity.1,2 The elevation of total blood copper levels during acute as well as chronic inflammatory states has been re...

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Determination of catechin in green tea using a catechol oxidase biomimetic sensor

Cited by 28 publications

References 27 publications

Determinação de catequinas por eletrodo de carbono impresso modificado com nanotubo de carbono funcionalizado

Determinação de catequinas por eletrodo de carbono impresso modificado com nanotubo de carbono funcionalizado

Electrochemical determination of catechol in tea samples using anthraquinone modified carbon paste electrode

Significant anti-inflammatory properties of a copper(II) fenoprofenate complex compared with its parent drug: Physical and chemical characterization of the complex

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