583-63-1Relevant articles and documents
Kinetic characterization of the oxidation of chlorogenic acid by polyphenol oxidase and peroxidase. Characteristics of the o-quinone
Munoz,Garcia-Molina,Varon,Rodriguez-Lopez,Garcia-Ruiz,Garcia-Canovas,Tudela
, p. 920 - 928 (2007)
Chlorogenic acid is the major diphenol of many fruits, where it is oxidized enzymatically by polyphenol oxidase (PPO) or peroxidase (POD) to its o-quinone. In spectrophotometric studies of chlorogenic acid oxidation with a periodate ratio of [CGA]0/[lO4-]0 0/[IO4-]0 > 1, the o-quinone was characterized as follows: λmax at 400 nm and ε = 2000 and 2200 M-1 cm-1 at pH 4.5 and 7.0, respectively. In studies of o-quinone generated by the oxidation of chlorogenic acid using a periodate at ratio of [CGA]0/[lO4-]0 > 1, a reaction with the remaining substrate was detected, showing rate constants of k = 2.73 ± 0.17 M-1 s-1 and k = 0.05 ± 0.01 M-1 s-1 at the above pH values. A Chronometric spectrophotometric method is proposed to kinetically characterize the action of the PPO or POD on the basis of measuring the time it takes for a given amount of ascorbic acid to be consumed in the reaction with the o-quinone. The kinetic constants of mushroom PPO and horseradish POD are determined.
Electrochemical biosensor for detection of 17β-estradiol using semi-conducting polymer and horseradish peroxidase
Cabaj, Joanna,Spychalska, Kamila,Zaj?c, Dorota
, p. 9079 - 9087 (2020)
A convenient electrochemical sensing pathway for 17β-estradiol detection was investigated. The system is based on a conducting polymer and horseradish peroxidase (HRP) modified platinum (Pt) electrode. The miniature estradiol biosensor was developed and constructed through the immobilization of HRP in an electroactive surface of the electrode covered with electroconducting polymer-poly(4,7-bis(5-(3,4-ethylenedioxythiophene)thiophen-2-yl)benzothiadiazole). The detection strategy is based on the fact that 17β-estradiol (E2) and pyrocatechol (H2Q) are co-substrates for the HRP enzyme. HRP, which does not react with E2, in the presence of H2O2 catalyses the oxidation of H2Q to o-benzoquinone (Q). With the optimized conditions, such constructed biosensing system demonstrated a convenient level of sensitivity, selectivity in a broad linear range-0.1 to 200 μM with a detection limit of 105 nM. Furthermore, the method was successfully applied for hormone detection in the presence of potential interfering compounds (ascorbic acid, estriol, estrone, uric acid and cholesterol).
Inhibition of mushroom tyrosinase by a newly synthesized ligand: Inhibition kinetics and computational simulations
Alijanianzadeh, Mahdi,Saboury, Ali Akbar,Hadi-Alijanvanda, Hamid,Moosavi-Movahedia, Ali Akbar,Ganjali, Mohammad Reza
, p. 448 - 459,12 (2012)
Alterations in the synthesis of melanin contribute to a number of diseases; therefore, the design of new tyrosinase inhibitors is very important. Mushroom tyrosinase (MT) is a metalloenzyme, which plays an important role in melanin biosynthesis. In this study, the inhibitory effect of a novel designed compound, i.e. 2-((1Z)-(2-(2,4-dinitrophenyl)hydrazin-1-ylidene)methyl) phenol, as a specific ligand which can bind to the copper ion of MT, has been assessed. The ligand was found to competitively inhibit both the cresolase and catecholase activities of MT, with small inhibition constants of 2.8 and 2.6 μM, respectively. Intrinsic fluorescence studies were performed to gain more information on the binding constants. Docking results indicated that the ligand binds to copper ions in the active site of MT via the OH group of the ligand. The ligand makes four hydrogen bonds with aspartic acid and one hydrogen bond with the histidine residue in the active site. Molecular dynamics results show that ligand binds to the MT via both electrostatic and hydrophobic interactions with its different parts. Copyright
Alzheimer's disease related copper(II)-β-amyloid peptide exhibits phenol monooxygenase and catechol oxidase activities
Da Silva, Giordano F. Z.,Ming, Li-June
, p. 5501 - 5504 (2005)
(Chemical Equation Presented) A gray area in gray matter: The Cu II complex of a truncated β-amyloid, CuAβ1-20, catalyzes the oxidation of catechol and the hydroxylation and oxidation of phenol (see picture) with dramatic rate accelerations (≈ 10 5-106-fold increases). The Cu-oxygen chemistry of CuAβ may offer both a better understanding of the chemical effect in the brains of patients who suffer from Alzheimer's disease as well as possible treatment strategies of this disease.
Complex Nonlinear Behavior in the Bromate–2-Aminophenol Reaction
Tang, Alexander,Bell, Jeffrey G.,Green, James R.,Wang, Jichang
, p. 21 - 27 (2017)
The bromate–2-aminophenol reaction in a batch reactor was investigated in this research, in which both simple and sequential oscillations were observed. The occurrence of sequential oscillations were found to be very sensitive to changes of the initial concentrations, where decreasing the concentration of sulfuric acid or sodium bromate or increasing the 2-aminophenol concentration caused the two oscillation windows to coalesce. Lowering the reaction temperature from 30 to 5°C also caused the two oscillation windows to merge into one. A phase diagram in the bromate–sulfuric acid concentration plane demonstrates that sequential oscillations only occur within a narrow band of conditions. Mechanistic studies of the system through employing 1H NMR and mass spectrometry suggest that a dibrominated ortho-benzoquinone is a major product. The oxidation of 2-aminophenol, on the other hand, can lead to the formation of pyrocatechol, which may be the substrate responsible for the second set of oscillations.
How well should the active site and the specific recognition be defined for proficient catalysis? - Effective and cooperative polyphenol/catechol oxidation and oxidative dna cleavage by a copper(II)-binding and H-bonding copolymer
Lykourinou, Vasiliki,Hanafy, Ahmed I.,Da Silva, Giordano F. Z.,Bisht, Kirpal S.,Larsen, Randy W.,Livingston, Brian T.,Angerhofer, Alexander,Ming, Li-June
, p. 2584 - 2592 (2008)
Despite the mainly inhomogeneous and unstructured nature of linear polymers, the CuII complex of a vinylpyridine-acrylamide copolymer exhibits very efficient 2-electron catalysis toward the oxidation of catechol and derivatives to form quinones with and without 80 mM (0.27%) H 2O2, showing remarkable (0.114-2.67) × 10 5 and (2.83-9.60) × 104-fold rate enhancements, respectively, in terms of first-order rate constant relative to auto-oxidation of the substrates in an aqueous environment under mild conditions. Metal-binding profiles suggest the presence of cooperativity in the catalysis. The oxidation catalysis is inhibited by the di-copper tyrosinase specific kojic acid. Moreover, electron paramagnetic resonance spectra reveal magnetic interaction of the CuII ions. On the basis of the results, the catalysis by this CuII-polymer seems to be consistent with the mechanism of type-3 di-copper oxidases. This complex also shows effective single- and double-stranded DNA cleavage in the presence of 1.0% H2O2. These studies suggest this CuII-polymer complex can serve as a unique chemical nuclease and a versatile chemical system for further exploration of Cu-oxygen chemistry. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
The enthalpies of formation of o-, m-, and p-benzoquinone: Gas-phase ion energetics, combustion calorimetry, and quantum chemical computations combined
Fattahi, Alireza,Kass, Steven R.,Liebman, Joel F.,Matos, M. Agostinha R.,Miranda, Margarida S.,Morais, Victor M. F.
, p. 6116 - 6122 (2005)
Radical anions of o-, m-, and p-benzoquinone were produced in a Fourier transform mass spectrometer by low energy electron attachment or collision-induced dissociation and were differentiated. Classical derivatization experiments also were carried out to
Synthesis and studies of the inhibitory effect of hydroxylated phenylpropanoids and biphenols derivatives on tyrosinase and laccase enzymes
Dettori, Maria Antonietta,Fabbri, Davide,Dessì, Alessandro,Dallocchio, Roberto,Carta, Paola,Honisch, Claudia,Ruzza, Paolo,Farina, Donatella,Migheli, Rossana,Serra, Pier Andrea,Pantaleoni, Roberto A.,Fois, Xenia,Rocchitta, Gaia,Delogu, Giovanna
, (2020/07/02)
The impaired activity of tyrosinase and laccase can provoke serious concerns in the life cycles of mammals, insects and microorganisms. Investigation of inhibitors of these two enzymes may lead to the discovery of whitening agents, medicinal products, anti-browning substances and compounds for controlling harmful insects and bacteria. A small collection of novel reversible tyrosinase and laccase inhibitors with a phenylpropanoid and hydroxylated biphenyl core was prepared using naturally occurring compounds and their activity was measured by spectrophotometric and electrochemical assays. Biosensors based on tyrosinase and laccase enzymes were constructed and used to detect the type of protein-ligand interaction and half maximal inhibitory concentration (IC50). Most of the inhibitors showed an IC50 in a range of 20–423 nM for tyrosinase and 23–2619 nM for laccase. Due to the safety concerns of conventional tyrosinase and laccase inhibitors, the viability of the new compounds was assayed on PC12 cells, four of which showed a viability of roughly 80% at 40 μM. In silico studies on the crystal structure of laccase enzyme identified a hydroxylated biphenyl bearing a prenylated chain as the lead structure, which activated strong and effective interactions at the active site of the enzyme. These data were confirmed by in vivo experiments performed on the insect model Tenebrio molitur.
Dearomatization of Electron-Deficient Phenols to ortho-Quinones: Bidentate Nitrogen-Ligated Iodine(V) Reagents
Xiao, Xiao,Greenwood, Nathaniel S.,Wengryniuk, Sarah E.
supporting information, p. 16181 - 16187 (2019/11/05)
Despite their broad utility, the synthesis of ortho-quinones remains a significant challenge, in particular, access to electron-deficient derivatives remains an unsolved problem. Reported here is the first general method for the synthesis of electron-deficient ortho-quinones by direct oxidation of phenols. The reaction is enabled by a novel bidentate nitrogen-ligated iodine(V) reagent, a previously unexplored class of compounds which we have termed Bi(N)-HVIs. The reaction is extremely general and proceeds with excellent regioselectivity for the ortho over para isomer. Functionalization of the ortho-quinone products was examined, resulting in a facile one-pot synthesis of catechols, as well as the incorporation of a variety of heteroatom nucleophiles. This method represents the first synthetic application of Bi(N)-HVIs and demonstrates their potential as a platform for the further development of highly reactive, but also highly tunable, I(V) reagents.
The Study of Mg(II) Ion Influence on Catechol Autoxidation in Weakly Alkaline Aqueous Solution
Nikoli?,?ivanovi?,Krsti?,Nikoli?
, p. 2656 - 2660 (2020/01/23)
Abstract: High performance liquid chromatography with diode array detection (HPLC-DAD) and electron spin resonance (ESR) spectroscopy were used to study Mg(II) ion influence on the autoxidation of catechol in weakly alkaline solution. The presence of Mg(II) ions greatly enhanced the catechol autoxidation rate and probably influenced the mechanism of reaction thus enabling formation of reaction products not obtained in the absence of metal ions. Consecutive formation of 1,2-benzoquinone, 2,3-oxanthrenediol, and 2,3-oxanthrenedione with intermediate o-semiquinone anion radicals during the initial stages of catechol autoxidation was suggested based on the detailed analysis of experimental HPLC-DAD and ESR data. The results of this study may help in better understanding of autoxidation of some biologically important catecholic molecules in real systems, where Mg(II) ions are ubiquitously present. Because of the possible toxicity of simple quinone molecules, it is important that the formation of relatively stable quinoid autoxidation products were detected in this study.
