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Jütte M, Wilbert JA, Reusing M, Abdighahroudi MS, Schüth C, Lutze HV. Reaction Mechanisms of Chlorine Dioxide with Phenolic Compounds─Influence of Different Substituents on Stoichiometric Ratios and Intrinsic Formation of Free Available Chlorine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18846-18855. [PMID: 37276343 DOI: 10.1021/acs.est.2c09496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chlorine dioxide (ClO2) is an oxidant applied in water treatment processes that is very effective for disinfection and abatement of inorganic and organic pollutants. Thereby phenol is the most important reaction partner of ClO2 in reactions of natural organic matter (NOM) and in pollutant degradation. It was previously reported that with specific reaction partners (e.g., phenol), free available chlorine (FAC) could form as another byproduct next to chlorite (ClO2-). This study investigates the impact of different functional groups attached to the aromatic ring of phenol on the formation of inorganic byproducts (i.e., FAC, ClO2-, chloride, and chlorate) and the overall reaction mechanism. The majority of the investigated compounds reacted with a 2:1 stoichiometry and formed 50% ClO2- and 50% FAC, regardless of the position and kind of the groups attached to the aromatic ring. The only functional groups strongly influencing the FAC formation in the ClO2 reaction with phenols were hydroxyl- and amino-substituents in ortho- and para-positions, causing 100% ClO2- and 0% FAC formation. Additionally, this class of compounds showed a pH-dependent stoichiometric ratio due to pH-dependent autoxidation. Overall, FAC is an important secondary oxidant in ClO2 based treatment processes. Synergetic effects in pollutant control and disinfection might be observable; however, the formation of halogenated byproducts needs to be considered as well.
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Affiliation(s)
- Mischa Jütte
- Technical University of Darmstadt, Institute IWAR, Chair of Environmental Analytics and Pollutants, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Janis A Wilbert
- Technical University of Darmstadt, Institute IWAR, Chair of Environmental Analytics and Pollutants, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Marcel Reusing
- Technical University of Darmstadt, Institute IWAR, Chair of Environmental Analytics and Pollutants, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Mohammad Sajjad Abdighahroudi
- Technical University of Darmstadt, Institute IWAR, Chair of Environmental Analytics and Pollutants, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
| | - Christoph Schüth
- Technical University of Darmstadt, Institute of Applied Geosciences, Schnittspahnstr. 9, 64287 Darmstadt, Germany
- IWW Water Centre, Moritzstraße 26, D-45476 Mülheim an der Ruhr, Germany
| | - Holger V Lutze
- Technical University of Darmstadt, Institute IWAR, Chair of Environmental Analytics and Pollutants, Franziska-Braun-Straße 7, 64287 Darmstadt, Germany
- IWW Water Centre, Moritzstraße 26, D-45476 Mülheim an der Ruhr, Germany
- Centre for Water and Environmental Research (ZWU), Universitätsstraße 5, D-45141 Essen, Germany
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Olson KR, Derry PJ, Kent TA, Straub KD. The Effects of Antioxidant Nutraceuticals on Cellular Sulfur Metabolism and Signaling. Antioxid Redox Signal 2023; 38:68-94. [PMID: 35819295 PMCID: PMC9885552 DOI: 10.1089/ars.2022.0077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 06/23/2022] [Indexed: 02/03/2023]
Abstract
Significance: Nutraceuticals are ingested for health benefits, in addition to their general nutritional value. These dietary supplements have become increasingly popular since the late 20th century and they are a rapidly expanding global industry approaching a half-trillion U.S. dollars annually. Many nutraceuticals are promulgated as potent antioxidants. Recent Advances: Experimental support for the efficacy of nutraceuticals has lagged behind anecdotal exuberance. However, accumulating epidemiological evidence and recent, well-controlled clinical trials are beginning to support earlier animal and in vitro studies. Although still somewhat limited, encouraging results have been suggested in essentially all organ systems and against a wide range of pathophysiological conditions. Critical Issues: Health benefits of "antioxidant" nutraceuticals are largely attributed to their ability to scavenge oxidants. This has been criticized based on several factors, including limited bioavailability, short tissue retention time, and the preponderance of endogenous antioxidants. Recent attention has turned to nutraceutical activation of downstream antioxidant systems, especially the Keap1/Nrf2 (Kelch like ECH associated protein 1/nuclear factor erythroid 2-related factor 2) axis. The question now becomes, how do nutraceuticals activate this axis? Future Directions: Reactive sulfur species (RSS), including hydrogen sulfide (H2S) and its metabolites, are potent activators of the Keap1/Nrf2 axis and avid scavengers of reactive oxygen species. Evidence is beginning to accumulate that a variety of nutraceuticals increase cellular RSS by directly providing RSS in the diet, or through a number of catalytic mechanisms that increase endogenous RSS production. We propose that nutraceutical-specific targeting of RSS metabolism will lead to the design and development of even more efficacious antioxidant therapeutic strategies. Antioxid. Redox Signal. 38, 68-94.
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Affiliation(s)
- Kenneth R. Olson
- Department of Physiology, Indiana University School of Medicine—South Bend, South Bend, Indiana, USA
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Paul J. Derry
- Center for Genomics and Precision Medicine, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas, USA
| | - Thomas A. Kent
- Center for Genomics and Precision Medicine, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas, USA
- Department of Chemistry, Rice University, Houston, Texas, USA
- Stanley H. Appel Department of Neurology, Houston Methodist Hospital and Research Institute, Houston, Texas, USA
| | - Karl D. Straub
- Central Arkansas Veteran's Healthcare System, Little Rock, Arkansas, USA
- Department of Medicine and Biochemistry, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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Makarova K, Olchowik-Grabarek E, Drabikowski K, Kurkowiak J, Zawada K. Products of Bisphenol A Degradation Induce Cytotoxicity in Human Erythrocytes (In Vitro). Int J Mol Sci 2022; 24:ijms24010492. [PMID: 36613931 PMCID: PMC9820436 DOI: 10.3390/ijms24010492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 12/29/2022] Open
Abstract
The aim of this work has been to study the possible degradation path of BPA under the Fenton reaction, namely to determine the energetically favorable intermediate products and to compare the cytotoxicity of BPA and its intermediate products of degradation. The DFT calculations of the Gibbs free energy at M06-2X/6-311G(d,p) level of theory showed that the formation of hydroquinone was the most energetically favorable path in a water environment. To explore the cytotoxicity the erythrocytes were incubated with BPA and three intermediate products of its degradation, i.e., phenol, hydroquinone and 4-isopropylphenol, in the concentrations 5-200 μg/mL, for 1, 4 and 24 h. BPA induced the strongest hemolytic changes in erythrocytes, followed by hydroquinone, phenol and 4-isopropylphenol. In the presence of hydroquinone, the highest level of RONS was observed, whereas BPA had the weakest effect on RONS generation. In addition, hydroquinone decreased the level of GSH the most. Generally, our results suggest that a preferable BPA degradation path under a Fenton reaction should be controlled in order to avoid the formation of hydroquinone. This is applicable to the degradation of BPA during waste water treatment and during chemical degradation in sea water.
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Affiliation(s)
- Katerina Makarova
- Department of Organic and Physical Chemistry, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland
- Correspondence:
| | - Ewa Olchowik-Grabarek
- Laboratory of Molecular Biophysics, Department of Microbiology and Biotechnology, Faculty of Biology, University of Bialystok, Konstanty Ciolkowskiego 1J, 15-245 Bialystok, Poland
| | - Krzysztof Drabikowski
- Laboratory of Biological Chemistry of Metal Ions, Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Justyna Kurkowiak
- Department of Organic and Physical Chemistry, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland
| | - Katarzyna Zawada
- Department of Organic and Physical Chemistry, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland
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Fratilescu I, Lascu A, Taranu BO, Epuran C, Birdeanu M, Macsim AM, Tanasa E, Vasile E, Fagadar-Cosma E. One A 3B Porphyrin Structure-Three Successful Applications. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:1930. [PMID: 35683785 PMCID: PMC9182125 DOI: 10.3390/nano12111930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/26/2022] [Accepted: 06/03/2022] [Indexed: 11/16/2022]
Abstract
Porphyrins are versatile structures capable of acting in multiple ways. A mixed substituted A3B porphyrin, 5-(3-hydroxy-phenyl)-10,15,20-tris-(3-methoxy-phenyl)-porphyrin and its Pt(II) complex, were synthesised and fully characterised by 1H- and 13C-NMR, TLC, UV-Vis, FT-IR, fluorescence, AFM, TEM and SEM with EDX microscopy, both in organic solvents and in acidic mediums. The pure compounds were used, firstly, as sensitive materials for sensitive and selective optical and fluorescence detection of hydroquinone with the best results in the range 0.039-6.71 µM and a detection limit of 0.013 µM and, secondly, as corrosion inhibitors for carbon-steel (OL) in an acid medium giving a best performance of 88% in the case of coverings with Pt-porphyrin. Finally, the electrocatalytic activity for the hydrogen and oxygen evolution reactions (HER and OER) of the free-base and Pt-metalated A3B porphyrins was evaluated in strong alkaline and acidic electrolyte solutions. The best results were obtained for the electrode modified with the metalated porphyrin, drop-casted on a graphite substrate from an N,N-dimethylformamide solution. In the strong acidic medium, the electrode displayed an HER overpotential of 108 mV, at i = -10 mA/cm2 and a Tafel slope value of 205 mV/dec.
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Affiliation(s)
- Ion Fratilescu
- Institute of Chemistry "Coriolan Dragulescu", Mihai Viteazu Ave. 24, 300223 Timisoara, Romania
| | - Anca Lascu
- Institute of Chemistry "Coriolan Dragulescu", Mihai Viteazu Ave. 24, 300223 Timisoara, Romania
| | - Bogdan Ovidiu Taranu
- National Institute for Research and Development in Electrochemistry and Condensed Matter, Plautius Andronescu Street 1, 300224 Timisoara, Romania
| | - Camelia Epuran
- Institute of Chemistry "Coriolan Dragulescu", Mihai Viteazu Ave. 24, 300223 Timisoara, Romania
| | - Mihaela Birdeanu
- National Institute for Research and Development in Electrochemistry and Condensed Matter, Plautius Andronescu Street 1, 300224 Timisoara, Romania
| | - Ana-Maria Macsim
- Institute of Macromolecular Chemistry "Petru Poni", Grigore Ghica Vodă Alley, No. 41A, 700487 Iasi, Romania
| | - Eugenia Tanasa
- Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, Splaiul Independentei 313, Sector 6, 060042 Bucharest, Romania
| | - Eugeniu Vasile
- Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, Splaiul Independentei 313, Sector 6, 060042 Bucharest, Romania
| | - Eugenia Fagadar-Cosma
- Institute of Chemistry "Coriolan Dragulescu", Mihai Viteazu Ave. 24, 300223 Timisoara, Romania
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Chen YH, Wang BK, Hou WC. Graphitic carbon nitride embedded with graphene materials towards photocatalysis of bisphenol A: The role of graphene and mediation of superoxide and singlet oxygen. CHEMOSPHERE 2021; 278:130334. [PMID: 34126674 DOI: 10.1016/j.chemosphere.2021.130334] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/14/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Composite photocatalysts comprising graphitic carbon nitride (g-C3N4) and graphene materials were synthesized and evaluated in the photocatalysis of bisphenol A (BPA) with a focus on elucidating the reaction mechanism. Embedding reduced graphene oxide (rGO) to g-C3N4 significantly accelerated the photocatalysis rate of BPA by three folds under visible light irradiation at neutral pH. We showed that rGO synthesized in intimate contact with g-C3N4 increased the surface areas and electrical conductivity of the g-C3N4 composites and promoted the electron-hole pair separation. The BPA photodegradation mechanism involved selective oxidants as superoxide (O2•-) and singlet oxygen (1O2) that were formed through one-electron reduction of O2 and the unique oxidation of O2•- by photogenerated hole (h+), respectively. The synthesized photocatalyst exhibited superior visible light photoreactivity to that of N-doped P25 TiO2, good photo-stability and reuse potential, and was operative in complex wastewater. rGO embedded g-C3N4 achieved good photomineralization of BPA at 80% in 4 h compared to 40% of bare g-C3N4. This study sheds light on the photocatalysis mechanism of BPA with a metal-free, promising rGO/g-C3N4 photocatalyst.
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Affiliation(s)
- Yu-Hsin Chen
- Department of Environmental Engineering, National Cheng Kung University, Tainan City, 70101, Taiwan
| | - Bo-Kai Wang
- Department of Environmental Engineering, National Cheng Kung University, Tainan City, 70101, Taiwan
| | - Wen-Che Hou
- Department of Environmental Engineering, National Cheng Kung University, Tainan City, 70101, Taiwan.
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Tentscher PR, Escher BI, Schlichting R, König M, Bramaz N, Schirmer K, von Gunten U. Toxic effects of substituted p-benzoquinones and hydroquinones in in vitro bioassays are altered by reactions with the cell assay medium. WATER RESEARCH 2021; 202:117415. [PMID: 34348209 DOI: 10.1016/j.watres.2021.117415] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/19/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
Substituted para-benzoquinones and hydroquinones are ubiquitous transformation products that arise during oxidative water treatment of phenolic precursors, for example through ozonation or chlorination. The benzoquinone structural motive is associated with mutagenicity and carcinogenicity, and also with induction of the oxidative stress response through the Nrf2 pathway. For either endpoint, toxicological data for differently substituted compounds are scarce. In this study, oxidative stress response, as indicated by the AREc32 in vitro bioassay, was induced by differently substituted para-benzoquinones, but also by the corresponding hydroquinones. Bioassays that indicate defense against genotoxicity (p53RE-bla) and DNA repair activity (UmuC) were not activated by these compounds. Stability tests conducted under incubation conditions, but in the absence of cell lines, showed that tested para-benzoquinones reacted rapidly with constituents of the incubation medium. Compounds were abated already in phosphate buffer, but even faster in biological media, with reactions attributed to amino- and thiol-groups of peptides, proteins, and free amino acids. The products of these reactions were often the corresponding substituted hydroquinones. Conversely, differently substituted hydroquinones were quantitatively oxidized to p-benzoquinones over the course of the incubation. The observed induction of the oxidative stress response was attributed to hydroquinones that are presumably oxidized to benzoquinones inside the cells. Despite the instability of the tested compounds in the incubation medium, the AREc32 in vitro bioassay could be used as an unspecific sum parameter to detect para-benzoquinones and hydroquinones in oxidatively treated waters.
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Affiliation(s)
- Peter R Tentscher
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf CH-8600, Switzerland; Department of Chemistry and Bioscience, Aalborg University, Aalborg 9220, Denmark
| | - Beate I Escher
- Department of Cell Toxicology, UFZ - Helmholtz Centre for Environmental Research, Leipzig 04318, Germany; Center for Applied Geoscience, Eberhard Karls University of Tübingen, Schnarrenbergstr. 94-96, Tübingen 72076, Germany
| | - Rita Schlichting
- Department of Cell Toxicology, UFZ - Helmholtz Centre for Environmental Research, Leipzig 04318, Germany
| | - Maria König
- Department of Cell Toxicology, UFZ - Helmholtz Centre for Environmental Research, Leipzig 04318, Germany
| | - Nadine Bramaz
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf CH-8600, Switzerland
| | - Kristin Schirmer
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf CH-8600, Switzerland; Department of Environmental Systems Science, ETH Zürich, Zürich CH-8092, Switzerland; Civil and Environmental Engineering (ENAC), School of Architecture, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf CH-8600, Switzerland; Civil and Environmental Engineering (ENAC), School of Architecture, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
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7
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Khan A, Zhang K, Sun P, Pan H, Cheng Y, Zhang Y. High performance of the A-Mn 2O 3 nanocatalyst for persulfate activation: Degradation process of organic contaminants via singlet oxygen. J Colloid Interface Sci 2021; 584:885-899. [PMID: 33268062 DOI: 10.1016/j.jcis.2020.10.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 12/14/2022]
Abstract
In this study, the catalytic activation of persulfate (PS) via metal oxides was investigated, and the A-Mn2O3 nanocatalyst was found to have the highest efficiency among other PS activators for the degradation of organic contaminants. Additionally, A-Mn2O3 exhibited a remarkable efficiency in activating PS for the degradation of phenol compared to both B-Mn2O3 and C-Mn2O3. This was attributed to the longer bonds between edge-sharing MnO6 octahedra, the unique structure, the high content surface -OH groups, and the average oxidation states. This indicated that all these properties played an important role in an efficient PS activation. Electron paramagnetic resonance (EPR) spectroscopy, scavenger tests, and chemical probes were conducted to investigate the reactive oxygen species (ROS). Singlet oxygen (1O2) was determined to be the main ROS generated from PS activation. A plausible mechanism study was proposed, which involved inner-sphere interactions. An electron transfer of the Mn species facilitated the decomposition of PS to generate HO2•/O2• - radicals, which were utilized as a precursor for 1O2 generation via direct oxidation or the recombination of HO2•/O2• -. Finally, the phenol and Sulfachloropyridazine (SCP) degradation pathways were proposed by 1O2 over the A-Mn2O3/PS system according to HPLC and LC-MS results.
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Affiliation(s)
- Aimal Khan
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Kaikai Zhang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Peng Sun
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Honghui Pan
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Yong Cheng
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Yanrong Zhang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China.
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Bu Y, Li H, Yu W, Pan Y, Li L, Wang Y, Pu L, Ding J, Gao G, Pan B. Peroxydisulfate Activation and Singlet Oxygen Generation by Oxygen Vacancy for Degradation of Contaminants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:2110-2120. [PMID: 33427455 DOI: 10.1021/acs.est.0c07274] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Oxygen vacancies (OVs) play a crucial role in the catalytic activity of metal-based catalysts; however, their activation mechanism toward peroxydisulfate (PDS) still lacks reasonable explanation. In this study, by taking bismuth bromide (BiOBr) as an example, we report an OV-mediated PDS activation process for degradation of bisphenol A (BPA) employing singlet oxygen (1O2) as the main reactive species under alkaline conditions. The experimental results show that the removal efficiency of BPA is proportional to the number of OVs and is highly related to the dosage of PDS and the catalyst. The surface OVs of BiOBr provide ideal sites for the inclusion of hydroxyl ions (HO-) to form BiIII-OH species, which are regarded as the major active sites for the adsorption and activation of PDS. Unexpectedly, the activation of PDS occurs through a nonradical mechanism mediated by 1O2, which is generated via multistep reactions, involving the formation of an intermediate superoxide radical (O2•-) and the redox cycle of Bi(III)/Bi(IV). This work is dedicated to the in-depth mechanism study into PDS activation over OV-rich BiOBr samples and provides a novel perspective for the activation of peroxides by defective materials in the absence of additional energy supply or aqueous transition metal ions.
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Affiliation(s)
- Yongguang Bu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Hongchao Li
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Wenjing Yu
- School of Environment and Chemical Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Yifan Pan
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Lijun Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Yanfeng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Liangtao Pu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Jie Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Guandao Gao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
- Research Center for Environmental Nanotechnology (ReCENT), Nanjing University, Nanjing 210023, China
| | - Bingcai Pan
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
- Research Center for Environmental Nanotechnology (ReCENT), Nanjing University, Nanjing 210023, China
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Oxidation of Hydrogen Sulfide by Quinones: How Polyphenols Initiate Their Cytoprotective Effects. Int J Mol Sci 2021; 22:ijms22020961. [PMID: 33478045 PMCID: PMC7835830 DOI: 10.3390/ijms22020961] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 12/15/2022] Open
Abstract
We have shown that autoxidized polyphenolic nutraceuticals oxidize H2S to polysulfides and thiosulfate and this may convey their cytoprotective effects. Polyphenol reactivity is largely attributed to the B ring, which is usually a form of hydroxyquinone (HQ). Here, we examine the effects of HQs on sulfur metabolism using H2S- and polysulfide-specific fluorophores (AzMC and SSP4, respectively) and thiosulfate sensitive silver nanoparticles (AgNP). In buffer, 1,4-dihydroxybenzene (1,4-DB), 1,4-benzoquinone (1,4-BQ), pyrogallol (PG) and gallic acid (GA) oxidized H2S to polysulfides and thiosulfate, whereas 1,2-DB, 1,3-DB, 1,2-dihydroxy,3,4-benzoquinone and shikimic acid did not. In addition, 1,4-DB, 1,4-BQ, PG and GA also increased polysulfide production in HEK293 cells. In buffer, H2S oxidation by 1,4-DB was oxygen-dependent, partially inhibited by tempol and trolox, and absorbance spectra were consistent with redox cycling between HQ autoxidation and H2S-mediated reduction. Neither 1,2-DB, 1,3-DB, 1,4-DB nor 1,4-BQ reduced polysulfides to H2S in either 21% or 0% oxygen. Epinephrine and norepinephrine also oxidized H2S to polysulfides and thiosulfate; dopamine and tyrosine were ineffective. Polyphenones were also examined, but only 2,5-dihydroxy- and 2,3,4-trihydroxybenzophenones oxidized H2S. These results show that H2S is readily oxidized by specific hydroxyquinones and quinones, most likely through the formation of a semiquinone radical intermediate derived from either reaction of oxygen with the reduced quinones, or from direct reaction between H2S and quinones. We propose that polysulfide production by these reactions contributes to the health-promoting benefits of polyphenolic nutraceuticals.
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Zhu M, Lu J, Hu Y, Liu Y, Hu S, Zhu C. Photochemical reactions between 1,4-benzoquinone and O 2•. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:31289-31299. [PMID: 32488712 DOI: 10.1007/s11356-020-09422-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
The superoxide anion radical (O2•-) is one of the most predominant reactive oxygen species (ROS), which is also involved in diverse chemical and biological processes. In this study, O2•- was generated by irradiating riboflavin in an O2-saturated solution using an ultraviolet lamp (λem = 365 nm) as the light source. The photochemical reduction of 1,4-benzoquinone (p-BQ) by O2•- was explored by 355-nm laser flash photolysis (LFP) and 365-nm UV light steady irradiation. The results showed that the photodecomposition efficiency of p-BQ was influenced by the riboflavin concentration, p-BQ initial concentration, and pH values. The superoxide anion radical originating from riboflavin photolysis served as a reductant to react with p-BQ, forming reduced BQ radicals (BQ•-) with a second-order rate constant of 1.1 × 109 L mol-1 s-1. The main product of the photochemical reaction between p-BQ and O2•- was hydroquinone (H2Q). The present work suggests that the reaction with O2•- is a potential transformation pathway of 1, 4-benzoquinone in atmospheric aqueous environments.
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Affiliation(s)
- Mengyu Zhu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China
- Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Jun Lu
- Center of Analysis & Measurement, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Yadong Hu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China
- Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Ying Liu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China
- Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Shuheng Hu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China
- Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Chengzhu Zhu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China.
- Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology, Hefei, 230009, People's Republic of China.
- Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei, 230009, People's Republic of China.
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11
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Zhu S, Huang X, Yang X, Peng P, Li Z, Jin C. Enhanced Transformation of Cr(VI) by Heterocyclic-N within Nitrogen-Doped Biochar: Impact of Surface Modulatory Persistent Free Radicals (PFRs). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:8123-8132. [PMID: 32491842 DOI: 10.1021/acs.est.0c02713] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Redox processes mediated by biochar(BC) enhanced the transformation of Cr(VI), which is largely dependent on the presence of PFRs as electron donors. Natural or artificial dopants in BC's could regulate inherent carbon configuration and PFRs. Until recently, the modulation of PFRs and transformation of Cr(VI) in BC by nonmetal-heterocyclic dopants was barely studied. In this study, changes in PFRs introduced by various nitrogen-dopants within BC are presented and the capacity for Cr(VI) transformation without light was investigated. It was found N-dopants were effectively embedded in carbon lattices through activated-Maillard reaction thus altering their charge and PFRs. Transformation of Cr(VI) in N doped biochar relied on mediated direct reduction by surface modulatory PFRs. The kinetic rate of transformation of Cr(VI) was increased 1.4-5 fold in N-BCs compared to nondoped BCs. Theortical calculation suggested a deficiency in surface electrons induced Lewis acid-base bonding which could acted as a bridge for electron transfer. Results of PCA and orbital energy indicated a colinear relationship between PFRs and pyrrolic N, as well as its dual-mode transformation of Cr(VI). This study provides an improved understanding of how N-doped BC contributes to the evolution of PFRs and their corresponding impacts on the transformation of Cr(VI) in environments.
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Affiliation(s)
- Shishu Zhu
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Xiaochen Huang
- School of Environment, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, 510632, China
| | - Xiaobao Yang
- Department of Physics, South China University of Technology, Guangzhou 510640, P. R. China
| | - Peng Peng
- Department of Mechanics and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Zhipeng Li
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai 264209, China
| | - Chao Jin
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, PR China
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12
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Rodríguez EM, von Gunten U. Generation of hydroxyl radical during chlorination of hydroxyphenols and natural organic matter extracts. WATER RESEARCH 2020; 177:115691. [PMID: 32304908 DOI: 10.1016/j.watres.2020.115691] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 06/11/2023]
Abstract
The generation of hydroxyl radicals (•OH) during the chlorination of air saturated solutions of different hydroxyphenols (hydroquinone, resorcinol, catechol, gallic and tannic acids) at pH 7 has been determined by the formation of phenol (in presence of benzene in excess) or 2-hydroxyterephthalic acid (in presence of terephthalic acid). Formation of •OH was only detected during the chlorination of o- or p-hydroxyphenols, compounds that react with chlorine by electron transfer forming the corresponding semiquinones/quinones. In aerated solutions, oxygen is reduced by the semiquinone to the superoxide radical, O2•-, which reacts with HOCl to •OH. Compared to the studied o-hydroxyphenols, the lower reactivity of hydroquinone towards chlorine favours the reaction between chlorine and O2•-, and its •OH formation potential is ∼50 times higher. The extent of •OH generated increased with the concentration of the hydroxyphenol and chlorine, but the •OH yield (moles formed per mole of hydroxyphenol eliminated), decreased due to the formation of the quinone, that acts as O2•- scavenger. The yield was almost not affected by the pH (6 ≤ pH ≤ 7.5), whereas a strong impact of dissolved O2 was observed. The •OH production was null in absence of O2 and 2.5-3 times higher at oxygen saturated conditions compared to air-saturated. Contrary to chlorination, during bromination of hydroquinone •OH was not formed, which can be attributable to a much faster consumption of the oxidant, with no chance for O2•- to react with bromine. Formation of •OH during the chlorination of different NOM extracts (SRHA, SRFA, PLFA and Nordic Lake NOM) and water from Lake Greifensee (Switzerland) was also studied using terephthalic acid as •OH scavenger. For SRHA, SRFA and Nordic Lake NOM (all of allochthonous origin and presenting high electron-donating capacity, EDC), •OH yields expressed as moles formed per mole of DOC0 (%), were between 1.1 and 2.0, similar to that of hydroquinone (∼1.5). For PLFA and Lake Greifensee water (autochthonous, lower EDC) much lower •OH yields were observed (0.1-0.3). Both chlorination rate and EDC, the later favouring the formation/stabilization of O2•-, seem to be key factors involved in •OH generation during the chlorination of NOM. A mechanism for these findings is proposed based on kinetic simulations of hydroquinone chlorination at pH 7.
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Affiliation(s)
- Eva M Rodríguez
- Departamento de Ingeniería Química y Química Física, Universidad de Extremadura, Avda. Elvas s/n, 06006, Badajoz, Spain; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Urs von Gunten
- School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland; Swiss Federal Institute of Technology, Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environment Systems (D-USYS), ETH Zurich, Universitätsstrasse 16, CH-8092, Zürich, Switzerland.
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13
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Matsui T, Yamada N, Kuno H, Kanaly RA. Formation of Bulky DNA Adducts by Non-Enzymatic Production of 1,2-Naphthoquinone-Epoxide from 1,2-Naphthoquinone under Physiological Conditions. Chem Res Toxicol 2019; 32:1760-1771. [PMID: 31430133 DOI: 10.1021/acs.chemrestox.9b00088] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Quinones may be formed metabolically or abiotically from environmental pollutants and polycyclic aromatic hydrocarbons (PAHs); many are recognized as toxicological intermediates that cause a variety of deleterious cellular effects including mutagenicity. The PAH-o-quinone, 1,2-naphthoquinone (1,2-NQ), may exert its genotoxic effects through interactions with cellular nucleophiles such as DNA, however, the mechanisms of 1,2-NQ adduct formation are still under investigation. With the aim to further understand these mechanisms, the chemical structures of adducts formed from the reaction of 2'-deoxyguanosine (dG) with 1,2-NQ under physiological conditions were investigated by liquid chromatography electrospray ionization tandem mass spectrometry and 1H NMR analyses. Results showed that 1,2-NQ underwent non-enzymatic oxidation to form a 1,2-NQ-epoxide which in turn formed at least four bulky adducts with dG, and these adducts were more likely to be formed under physiological conditions. A mechanism was proposed whereby hydration of 1,2-NQ to form unstable naphthohydroquinones and 2-hydroxy-1,4-naphthoquinone resulted in formation of hydrogen peroxide that oxidized 1,2-NQ. These results suggest that the genotoxicity of 1,2-NQ may not only be caused through oxidative DNA damage and adduct formation through Michael addition but also through non-enzymatic oxidative transformation of 1,2-NQ itself to form an intermediate PAH-epoxide which covalently binds to DNA.
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Affiliation(s)
- Takuya Matsui
- Department of Life and Environmental System Science, Graduate School of Nanobiosciences , Yokohama City University , 22-2 Seto, Kanazawa , Yokohama , Kanagawa 236-0027 , Japan.,Toxicology Research Laboratories , Central Pharmaceutical Research Institute Japan Tobacco, Inc. , 1-13-2 Fukuura, Kanazawa-ku , Yokohama-city , Kanagawa 236-0004 , Japan
| | - Naohito Yamada
- Toxicology Research Laboratories , Central Pharmaceutical Research Institute Japan Tobacco, Inc. , 1-13-2 Fukuura, Kanazawa-ku , Yokohama-city , Kanagawa 236-0004 , Japan
| | - Hideyuki Kuno
- Toxicology Research Laboratories , Central Pharmaceutical Research Institute Japan Tobacco, Inc. , 1-13-2 Fukuura, Kanazawa-ku , Yokohama-city , Kanagawa 236-0004 , Japan
| | - Robert A Kanaly
- Department of Life and Environmental System Science, Graduate School of Nanobiosciences , Yokohama City University , 22-2 Seto, Kanazawa , Yokohama , Kanagawa 236-0027 , Japan
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14
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Ma J, Zhou H, Yan S, Song W. Kinetics studies and mechanistic considerations on the reactions of superoxide radical ions with dissolved organic matter. WATER RESEARCH 2019; 149:56-64. [PMID: 30419467 DOI: 10.1016/j.watres.2018.10.081] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/23/2018] [Accepted: 10/28/2018] [Indexed: 06/09/2023]
Abstract
Superoxide ion (O2•-) is one of the short lived reactive oxygen species (ROS) formed in aquatic environments. The reactions of O2•- with the model dissolved organic matter (DOM) were studied using a chemiluminescent analysis method under relevant environmental conditions. The reaction of O2•- with DOM produced reduced DOM (DOM•-) by fast one-electron-transfer in the initial stage. This process resulted an initial "loss" in the O2•- decay kinetics. DOM•- is unstable which will continue react with O2•- generating H2O2 to complete a catalytic dismutation cycle. Based on analyzing the observed pseudo-first order O2•- decay rates (kpseudo), the quasi-steady-state concentration of DOM•- is found to be equal to the initial loss of O2•-. Thus, the rate constant for DOM•- with HO2•/O2•- is derived to be (1.1-1.9) × 106 M-1 s-1 in the temperature range of 7.8-41.4 °C. Meanwhile, the apparent rate constant for DOM with O2•- in a flow cell during a short time (2.25 s) is measured as (1.5-3.3) × 103 MC-1 s-1 in the temperature range of 8.2-38.6 °C. These temperature dependent O2•- reaction rate constants present an apparent activation energy of (19.6 ± 2.9) kJ molC-1 for DOM, while that of DOM•- (12.5 ± 3.5 kJ mol-1) is lower. For the pseudo-first order decay rate of O2•-, the catalyzed-dismutation by metal components ranges from 13 to 23%; the contribution by aromatic ketones of DOM is estimated to be 10-13% by using NaBH4 reduction method. The residual contribution might mainly occur at the quinone-like groups, which contributed 64%-77% to the total dismutation. The pH effects on the apparent catalytic rate constants dominate the reaction of O2•- with DOM. The present work suggests that DOM is an important sink for O2•- in aquatic environments. Furthermore, we proposed that the reaction of O2•- with DOM could be a potential source of DOM•- in natural water.
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Affiliation(s)
- Jianzhong Ma
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Huaxi Zhou
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Shuwen Yan
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200080, PR China
| | - Weihua Song
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200080, PR China.
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15
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Zhu S, Li X, Kang J, Duan X, Wang S. Persulfate Activation on Crystallographic Manganese Oxides: Mechanism of Singlet Oxygen Evolution for Nonradical Selective Degradation of Aqueous Contaminants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:307-315. [PMID: 30479119 DOI: 10.1021/acs.est.8b04669] [Citation(s) in RCA: 379] [Impact Index Per Article: 75.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Minerals and transitional metal oxides of earth-abundant elements are desirable catalysts for in situ chemical oxidation in environmental remediation. However, catalytic activation of peroxydisulfate (PDS) by manganese oxides was barely investigated. In this study, one-dimension manganese dioxides (α- and β-MnO2) were discovered as effective PDS activators among the diverse manganese oxides for selective degradation of organic contaminants. Compared with other chemical states and crystallographic structures of manganese oxide, β-MnO2 nanorods exhibited the highest phenol degradation rate (0.044 min-1, 180 min) by activating PDS. A comprehensive study was conducted utilizing electron paramagnetic resonance, chemical probes, radical scavengers, and different solvents to identity the reactive oxygen species (ROS). Singlet oxygen (1O2) was unveiled to be the primary ROS, which was generated by direct oxidation or recombination of superoxide ions and radicals from a metastable manganese intermediate at neutral pH. The study dedicates to the first mechanistic study into PDS activation over manganese oxides and provides a novel catalytic system for selective removal of organic contaminants in wastewater.
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Affiliation(s)
- Shishu Zhu
- Department of Chemical Engineering , Curtin University , GPO Box U1987, Perth , Western Australia 6845 , Australia
- State Key Laboratory of Urban Water Resource and Environment , Harbin Institute of Technology , 73 Huanghe Road , Harbin 150090 , P. R. China
| | - Xiaojie Li
- Department of Chemical Engineering , Curtin University , GPO Box U1987, Perth , Western Australia 6845 , Australia
| | - Jian Kang
- Department of Chemical Engineering , Curtin University , GPO Box U1987, Perth , Western Australia 6845 , Australia
| | - Xiaoguang Duan
- School of Chemical Engineering , The University of Adelaide , Adelaide , South Australia 5005 , Australia
| | - Shaobin Wang
- Department of Chemical Engineering , Curtin University , GPO Box U1987, Perth , Western Australia 6845 , Australia
- School of Chemical Engineering , The University of Adelaide , Adelaide , South Australia 5005 , Australia
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16
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Yuan X, Davis JA, Nico PS. Iron-Mediated Oxidation of Methoxyhydroquinone under Dark Conditions: Kinetic and Mechanistic Insights. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:1731-1740. [PMID: 26789138 DOI: 10.1021/acs.est.5b03939] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Despite the biogeochemical significance of the interactions between natural organic matter (NOM) and iron species, considerable uncertainty still remains as to the exact processes contributing to the rates and extents of complexation and redox reactions between these important and complex environmental components. Investigations on the reactivity of low-molecular-weight quinones, which are believed to be key redox active compounds within NOM, toward iron species, could provide considerable insight into the kinetics and mechanisms of reactions involving NOM and iron. In this study, the oxidation of 2-methoxyhydroquinone (MH2Q) by ferric iron (Fe(III)) under dark conditions in the absence and presence of oxygen was investigated within a pH range of 4-6. Although Fe(III) was capable of stoichiometrically oxidizing MH2Q under anaerobic conditions, catalytic oxidation of MH2Q was observed in the presence of O2 due to further cycling between oxygen, semiquinone radicals, and iron species. A detailed kinetic model was developed to describe the predominant mechanisms, which indicated that both the undissociated and monodissociated anions of MH2Q were kinetically active species toward Fe(III) reduction, with the monodissociated anion being the key species accounting for the pH dependence of the oxidation. The generated radical intermediates, namely semiquinone and superoxide, are of great importance in reaction-chain propagation. The kinetic model may provide critical insight into the underlying mechanisms of the thermodynamic and kinetic characteristics of metal-organic interactions and assist in understanding and predicting the factors controlling iron and organic matter transformation and bioavailability in aquatic systems.
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Affiliation(s)
- Xiu Yuan
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
| | - James A Davis
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Peter S Nico
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
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17
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New insights of superoxide dismutase inhibition of pyrogallol autoxidation. Mol Cell Biochem 2014; 400:277-85. [DOI: 10.1007/s11010-014-2284-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/15/2014] [Indexed: 11/28/2022]
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18
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Yuan X, Miller CJ, Pham AN, Waite TD. Kinetics and mechanism of auto- and copper-catalyzed oxidation of 1,4-naphthohydroquinone. Free Radic Biol Med 2014; 71:291-302. [PMID: 24681336 DOI: 10.1016/j.freeradbiomed.2014.03.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/19/2014] [Accepted: 03/15/2014] [Indexed: 11/23/2022]
Abstract
Although quinones represent a class of organic compounds that may exert toxic effects both in vitro and in vivo, the molecular mechanisms involved in quinone species toxicity are still largely unknown, especially in the presence of transition metals, which may both induce the transformation of the various quinone species and result in generation of harmful reactive oxygen species. In this study, the oxidation of 1,4-naphthohydroquinone (NH2Q) in the absence and presence of nanomolar concentrations of Cu(II) in 10 mM NaCl solution over a pH range of 6.5-7.5 has been investigated, with detailed kinetic models developed to describe the predominant mechanisms operative in these systems. In the absence of copper, the apparent oxidation rate of NH2Q increased with increasing pH and initial NH2Q concentration, with concomitant oxygen consumption and peroxide generation. The doubly dissociated species, NQ(2-), has been shown to be the reactive species with regard to the one-electron oxidation by O2 and comproportionation with the quinone species, both generating the semiquinone radical (NSQ(·-)). The oxidation of NSQ(·-) by O2 is shown to be the most important pathway for superoxide (O2(·-)) generation with a high intrinsic rate constant of 1.0×10(8)M(-1)s(-1). Both NSQ(·-) and O2(·-) served as chain-propagating species in the autoxidation of NH2Q. Cu(II) is capable of catalyzing the oxidation of NH2Q in the presence of O2 with the oxidation also accelerated by increasing the pH. Both the uncharged (NH2Q(0)) and the mono-anionic (NHQ(-)) species were found to be the kinetically active forms, reducing Cu(II) with an intrinsic rate constant of 4.0×10(4) and 1.2×10(7)M(-1)s(-1), respectively. The presence of O2 facilitated the catalytic role of Cu(II) by rapidly regenerating Cu(II) via continuous oxidation of Cu(I) and also by efficient removal of NSQ(·-) resulting in the generation of O2(·-). The half-cell reduction potentials of various redox couples at neutral pH indicated good agreement between thermodynamic and kinetic considerations for various key reactions involved, further validating the proposed mechanisms involved in both the autoxidation and the copper-catalyzed oxidation of NH2Q in circumneutral pH solutions.
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Affiliation(s)
- Xiu Yuan
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Christopher J Miller
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - A Ninh Pham
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - T David Waite
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
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Yuan X, Pham AN, Miller CJ, Waite TD. Copper-catalyzed hydroquinone oxidation and associated redox cycling of copper under conditions typical of natural saline waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:8355-8364. [PMID: 23796190 DOI: 10.1021/es4014344] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A detailed kinetic model has been developed to describe the oxidation of Cu(I) by O2 and the reduction of Cu(II) by 1,4-hydroquinone (H2Q) in the presence of O2 in 0.7 M NaCl solution over a pH range of 6.5-8.0. The reaction between Cu(I) and O2 is shown to be the most important pathway in the overall oxidation of Cu(I), with the rate constant for this oxidation process increasing with an increasing pH. In 0.7 M NaCl solutions, Cu(II) is capable of catalyzing the oxidation of H2Q in the presence of O2 with the monoanion, HQ(-), the kinetically active hydroquinone form, reducing Cu(II) with an intrinsic rate constant of (5.0 ± 0.4) × 10(7) M(-1) s(-1). Acting as a chain-propagating species, the deprotonated semiquinone radical (SQ(•) (-)) generated from both the one-electron oxidation of H2Q and the one-electron reduction of 1,4-benzoquinone (BQ) also reacts rapidly with Cu(II) and Cu(I), with the same rate constant of (2.0 ± 0.5) × 10(7) M(-1) s(-1). In addition to its role in reformation of Cu(II) via continuous oxidation of Cu(I), O2 rapidly removes SQ(•) (-), resulting in the generation of O2(•) (-). Agreement between half-cell reduction potentials of different redox couples provides confirmation of the veracity of the proposed model describing the interactions of copper and quinone species in circumneutral pH saline solutions.
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Affiliation(s)
- Xiu Yuan
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia
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20
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Sarsour EH, Kumar MG, Kalen AL, Goswami M, Buettner GR, Goswami PC. MnSOD activity regulates hydroxytyrosol-induced extension of chronological lifespan. AGE (DORDRECHT, NETHERLANDS) 2012; 34:95-109. [PMID: 21384152 PMCID: PMC3260369 DOI: 10.1007/s11357-011-9223-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 02/15/2011] [Indexed: 05/30/2023]
Abstract
Chronological lifespan (CLS) is defined as the duration of quiescence in which normal cells retain the capacity to reenter the proliferative cycle. This study investigates whether hydroxytyrosol (HT), a naturally occurring polyphenol found in olives, extends CLS in normal human fibroblasts (NHFs). Quiescent NHFs cultured for a long duration (30-60 days) lose their capacity to repopulate. Approximately 60% of these cells exit the cell cycle permanently; a significant increase in the doubling time of the cell population was observed. CLS was extended in quiescent NHFs that were cultured in the presence of HT for 30-60 days. HT-induced extension of CLS was associated with an approximately 3-fold increase in manganese superoxide dismutase (MnSOD) activity while there was no change in copper-zinc superoxide dismutase, catalase, or glutathione peroxidase protein levels. Quiescent NHFs overexpressing a dominant-negative mutant form of MnSOD failed to extend CLS. HT suppressed age-associated increase in mitochondrial ROS levels. Results from spectroscopy assays indicate that HT in the presence of peroxidases can undergo catechol-semiquinone-quinone redox cycling generating superoxide, which in a cellular context can activate the antioxidant system, e.g., MnSOD expression. These results demonstrate that HT extends CLS by increasing MnSOD activity and decreasing age-associated mitochondrial reactive oxygen species accumulation.
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Affiliation(s)
- Ehab H. Sarsour
- Free Radical and Radiation Biology Division, Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242-1181 USA
| | - Maneesh G. Kumar
- Free Radical and Radiation Biology Division, Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242-1181 USA
| | - Amanda L. Kalen
- Free Radical and Radiation Biology Division, Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242-1181 USA
| | - Monali Goswami
- Free Radical and Radiation Biology Division, Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242-1181 USA
| | - Garry R. Buettner
- Free Radical and Radiation Biology Division, Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242-1181 USA
| | - Prabhat C. Goswami
- Free Radical and Radiation Biology Division, Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242-1181 USA
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Anderson DG, Mariappan SVS, Buettner GR, Doorn JA. Oxidation of 3,4-dihydroxyphenylacetaldehyde, a toxic dopaminergic metabolite, to a semiquinone radical and an ortho-quinone. J Biol Chem 2011; 286:26978-86. [PMID: 21642436 DOI: 10.1074/jbc.m111.249532] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The oxidation and toxicity of dopamine is believed to contribute to the selective neurodegeneration associated with Parkinson disease. The formation of reactive radicals and quinones greatly contributes to dopaminergic toxicity through a variety of mechanisms. The physiological metabolism of dopamine to 3,4-dihydroxyphenylacetaldehyde (DOPAL) via monoamine oxidase significantly increases its toxicity. To more adequately explain this enhanced toxicity, we hypothesized that DOPAL is capable of forming radical and quinone species upon oxidation. Here, two unique oxidation products of DOPAL are identified. Several different oxidation methods gave rise to a transient DOPAL semiquinone radical, which was characterized by electron paramagnetic resonance spectroscopy. NMR identified the second oxidation product of DOPAL as the ortho-quinone. Also, carbonyl hydration of DOPAL in aqueous media was evident via NMR. Interestingly, the DOPAL quinone exists exclusively in the hydrated form. Furthermore, the enzymatic and chemical oxidation of DOPAL greatly enhance protein cross-linking, whereas auto-oxidation results in the production of superoxide. Also, DOPAL was shown to be susceptible to oxidation by cyclooxygenase-2 (COX-2). The involvement of this physiologically relevant enzyme in both oxidative stress and Parkinson disease underscores the potential importance of DOPAL in the pathogenesis of this condition.
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Affiliation(s)
- David G Anderson
- Division of Medicinal and Natural Products Chemistry, College of Pharmacy, University of Iowa, Iowa City, Iowa 52242-1112, USA
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Heller MI, Croot PL. Kinetics of superoxide reactions with dissolved organic matter in tropical Atlantic surface waters near Cape Verde (TENATSO). ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jc006021] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Chaudhuri L, Sarsour EH, Goswami PC. 2-(4-Chlorophenyl)benzo-1,4-quinone induced ROS-signaling inhibits proliferation in human non-malignant prostate epithelial cells. ENVIRONMENT INTERNATIONAL 2010; 36:924-930. [PMID: 20163859 PMCID: PMC2888671 DOI: 10.1016/j.envint.2010.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 01/04/2010] [Accepted: 01/05/2010] [Indexed: 05/28/2023]
Abstract
Polychlorinated biphenyls (PCBs) and their metabolites are environmental chemical contaminants which can produce reactive oxygen species (ROS) by auto-oxidation of di-hydroxy PCBs as well as the reduction of quinones and redox-cycling. We investigate the hypothesis that 2-(4-chlorophenyl)benzo-1,4-quinone (4-Cl-BQ), a metabolite of 4-chlorobiphenyl (PCB3), induced ROS-signaling inhibits cellular proliferation. Monolayer cultures of exponentially growing asynchronous human non-malignant prostate epithelial cells (RWPE-1) were incubated with 0-6 μM of 4-Cl-BQ and harvested at the end of 72 h of incubation to assess antioxidant enzyme expression, cellular ROS levels, cell growth, and cell cycle phase distributions. 4-Cl-BQ decreased manganese superoxide dismutase (MnSOD) activity, protein, and mRNA levels. 4-Cl-BQ treatment increased dihydroethidium (DHE) fluorescence, which was suppressed in cells pretreated with polyethylene glycol conjugated superoxide dismutase (PEG-SOD). The increase in ROS levels was associated with a decrease in cell growth, and an increase in the percentage of S-phase cells. These effects were suppressed in cells pretreated with PEG-SOD. 4-Cl-BQ treatment did not change the protein levels of phosphorylated H2AX at the end of 72 h of incubation, suggesting that the inhibition in cell growth and accumulation of cells in S-phase at the end of the treatments were probably not due to 4-Cl-BQ induced DNA double strand break. These results demonstrate that MnSOD activity and ROS-signaling perturb proliferation in 4-Cl-BQ treated in vitro cultures of human prostate cells.
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Affiliation(s)
- Leena Chaudhuri
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Ehab H. Sarsour
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Prabhat C. Goswami
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
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Song Y, Buettner GR. Thermodynamic and kinetic considerations for the reaction of semiquinone radicals to form superoxide and hydrogen peroxide. Free Radic Biol Med 2010; 49:919-62. [PMID: 20493944 PMCID: PMC2936108 DOI: 10.1016/j.freeradbiomed.2010.05.009] [Citation(s) in RCA: 224] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 05/10/2010] [Accepted: 05/12/2010] [Indexed: 10/19/2022]
Abstract
The quinone/semiquinone/hydroquinone triad (Q/SQ(*-)/H(2)Q) represents a class of compounds that has great importance in a wide range of biological processes. The half-cell reduction potentials of these redox couples in aqueous solutions at neutral pH, E degrees ', provide a window to understanding the thermodynamic and kinetic characteristics of this triad and their associated chemistry and biochemistry in vivo. Substituents on the quinone ring can significantly influence the electron density "on the ring" and thus modify E degrees' dramatically. E degrees' of the quinone governs the reaction of semiquinone with dioxygen to form superoxide. At near-neutral pH the pK(a)'s of the hydroquinone are outstanding indicators of the electron density in the aromatic ring of the members of these triads (electrophilicity) and thus are excellent tools to predict half-cell reduction potentials for both the one-electron and two-electron couples, which in turn allow estimates of rate constants for the reactions of these triads. For example, the higher the pK(a)'s of H(2)Q, the lower the reduction potentials and the higher the rate constants for the reaction of SQ(*-) with dioxygen to form superoxide. However, hydroquinone autoxidation is controlled by the concentration of di-ionized hydroquinone; thus, the lower the pK(a)'s the less stable H(2)Q to autoxidation. Catalysts, e.g., metals and quinone, can accelerate oxidation processes; by removing superoxide and increasing the rate of formation of quinone, superoxide dismutase can accelerate oxidation of hydroquinones and thereby increase the flux of hydrogen peroxide. The principal reactions of quinones are with nucleophiles via Michael addition, for example, with thiols and amines. The rate constants for these addition reactions are also related to E degrees'. Thus, pK(a)'s of a hydroquinone and E degrees ' are central to the chemistry of these triads.
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Affiliation(s)
- Yang Song
- College of Pharmaceutical Sciences, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Southwest University, Chongqing, 400715, People's Republic of China
- Free Radical and Radiation Biology Program, The University of Iowa, Iowa City, IA 52242-1181, USA
| | - Garry R. Buettner
- Free Radical and Radiation Biology Program, The University of Iowa, Iowa City, IA 52242-1181, USA
- Human Toxicology Program, The University of Iowa, Iowa City, IA 52242-1181, USA
- Corresponding author. Free Radical and Radiation Biology, ESR Facility, Med Labs B180, The University of Iowa Iowa City, IA 52242-1181. Fax: +1 319 335 8039. (G.R. Buettner)
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Nonenzymatic displacement of chlorine and formation of free radicals upon the reaction of glutathione with PCB quinones. Proc Natl Acad Sci U S A 2009; 106:9725-30. [PMID: 19497881 DOI: 10.1073/pnas.0810352106] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The reactions of glutathione (GSH) with polychlorinated biphenyl (PCB) quinones having different degrees of chlorination on the quinone ring were examined. EPR spectroscopy and MS revealed 2 types of reactions yielding different products: (i) a nonenzymatic, nucleophilic displacement of chlorine on the quinone ring yielding a glutathiylated conjugated quinone and (ii) Michael addition of GSH to the quinone, a 2-electron reduction, yielding a glutathiylated conjugated hydroquinone. The pK(a) of parent hydroquinone decreased by 1 unit as the degree of chlorination increased. This resulted in a corresponding increase in the oxidizability of these chlorinated hydroquinones. The reaction with oxygen appears to be first-order each in ionized hydroquinone and dioxygen, yielding hydrogen peroxide stoichiometrically. The generation of semiquinone radicals, superoxide, and hydroxyl radicals was observed by EPR; however, the mechanisms and yields vary depending on the degree of the chlorination of hydroquinone/quinone and the presence or absence of GSH. Our discovery that chlorinated quinones undergo a rapid, nonenzymatic dechlorination upon reaction with GSH opens a different view on mechanisms of metabolism and the toxicity of this class of compounds.
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An ultrasensitive and highly selective determination method for quinones by high-performance liquid chromatography with photochemically initiated luminol chemiluminescence. J Chromatogr A 2009; 1216:3977-84. [DOI: 10.1016/j.chroma.2009.03.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 03/02/2009] [Accepted: 03/06/2009] [Indexed: 11/21/2022]
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Abstract
Potential metabolic mechanisms underlying the haemopoietic toxicity of benzene include bioactivation of phenolic metabolites of benzene by peroxidases in bone marrow and ring opening reactions to generate muconate derivatives. Peroxidase-mediated activation of phenolic metabolites of benzene generates reactive quinones which can be detoxified by NAD(P)H:quinone acceptor oxidoreductase (NQO1). The major peroxidase enzyme in bone marrow is myeloperoxidase (MPO) and potential target cells for phenolic metabolites of benzene were characterized in bone marrow stroma on the basis of high MPO:NQO1 ratios. MPO was found to be expressed at the level of myeloid progenitor cells in both murine (lineage negative cells) and human (CD34+ cells) systems. This suggests that progenitor cells may be relevant targets of phenolic metabolites of benzene resulting in aberrant haemopoiesis. A polymorphism in NQO1 is also described which leads to a complete lack of NQO1 activity. The toxicological significance of this polymorphism with respect to benzene toxicity is under investigation.
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Affiliation(s)
- D Ross
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Health Sciences Center, Denver 80262, USA.
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Venkatesha VA, Venkataraman S, Sarsour EH, Kalen AL, Buettner GR, Robertson LW, Lehmler HJ, Goswami PC. Catalase ameliorates polychlorinated biphenyl-induced cytotoxicity in nonmalignant human breast epithelial cells. Free Radic Biol Med 2008; 45:1094-102. [PMID: 18691649 PMCID: PMC2614346 DOI: 10.1016/j.freeradbiomed.2008.07.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 06/16/2008] [Accepted: 07/07/2008] [Indexed: 11/29/2022]
Abstract
Polychlorinated biphenyls (PCBs) are environmental chemical contaminants believed to adversely affect cellular processes. We investigated the hypothesis that PCB-induced changes in the levels of cellular reactive oxygen species (ROS) induce DNA damage resulting in cytotoxicity. Exponentially growing cultures of human nonmalignant breast epithelial cells (MCF10A) were incubated with PCBs for 3 days and assayed for cell number, ROS levels, DNA damage, and cytotoxicity. Exposure to 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) or 2-(4-chlorophenyl)benzo-1,4-quinone (4-Cl-BQ), a metabolite of 4-chlorobiphenyl (PCB3), significantly decreased cell number and MTS reduction and increased the percentage of cells with sub-G1 DNA content. Results from electron paramagnetic resonance (EPR) spectroscopy showed a 4-fold increase in the steady-state levels of ROS, which was suppressed in cells pretreated with catalase. EPR measurements in cells treated with 4-Cl-BQ detected the presence of a semiquinone radical, suggesting that the increased levels of ROS could be due to the redox cycling of 4-Cl-BQ. A dose-dependent increase in micronuclei frequency was observed in PCB-treated cells, consistent with an increase in histone 2AX phosphorylation. Treatment of cells with catalase blunted the PCB-induced increase in micronuclei frequency and H2AX phosphorylation that was consistent with an increase in cell survival. Our results demonstrate a PCB-induced increase in cellular levels of ROS causing DNA damage, resulting in cell killing.
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Affiliation(s)
- Venkatasubbaiah A. Venkatesha
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa
| | - Sujatha Venkataraman
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa
| | - Ehab H. Sarsour
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa
| | - Amanda L. Kalen
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa
| | - Garry R. Buettner
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa
| | - Larry W. Robertson
- Occupational & Environmental Health, The University of Iowa, Iowa City, Iowa
| | | | - Prabhat C. Goswami
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa
- Address for correspondence to: Prabhat C. Goswami, PhD, B180 Medical Laboratories, The Free Radical & Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242-1181, Fax: 319-335-8039, E-mail:
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29
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Song Y, Wagner BA, Lehmler HJ, Buettner GR. Semiquinone radicals from oxygenated polychlorinated biphenyls: electron paramagnetic resonance studies. Chem Res Toxicol 2008; 21:1359-67. [PMID: 18549251 PMCID: PMC2740386 DOI: 10.1021/tx8000175] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Polychlorinated biphenyls (PCBs) can be oxygenated to form very reactive hydroquinone and quinone products. A guiding hypothesis in the PCB research community is that some of the detrimental health effects of some PCBs are a consequence of these oxygenated forms undergoing one-electron oxidation or reduction, generating semiquinone radicals (SQ•−). These radicals can enter into a futile redox cycle resulting in the formation of reactive oxygen species, that is, superoxide and hydrogen peroxide. Here, we examine some of the properties and chemistry of these semiquinone free radicals. Using electron paramagnetic resonance (EPR) to detect SQ•− formation, we observed that (i) xanthine oxidase can reduce quinone PCBs to the corresponding SQ•−; (ii) the heme-containing peroxidases (horseradish and lactoperoxidase) can oxidize hydroquinone PCBs to the corresponding SQ•−; (iii) tyrosinase acting on PCB ortho-hydroquinones leads to the formation of SQ•−; (iv) mixtures of PCB quinone and hydroquinone form SQ•− via a comproportionation reaction; (v) SQ•− are formed when hydroquinone-PCBs undergo autoxidation in high pH buffer (≈>pH 8); and, surprisingly, (vi) quinone-PCBs in high pH buffer can also form SQ•−; (vii) these observations along with EPR suggest that hydroxide anion can add to the quinone ring; (viii) H2O2 in basic solution reacts rapidly with PCB-quinones; and (ix) at near-neutral pH SOD can catalyze the oxidization of PCB-hydroquinone to quinone, yielding H2O2. However, using 5,5-dimethylpyrroline-1-oxide (DMPO) as a spin-trapping agent, we did not trap superoxide, indicating that generation of superoxide from SQ•− is not kinetically favorable. These observations demonstrate multiple routes for the formation of SQ•− from PCB-quinones and hydroquinones. Our data also point to futile redox cycling as being one mechanism by which oxygenated PCBs can lead to the formation of reactive oxygen species, but this is most efficient in the presence of SOD.
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Affiliation(s)
- Yang Song
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242-1101, USA
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Inoue D, Hara S, Kashihara M, Murai Y, Danzl E, Sei K, Tsunoi S, Fujita M, Ike M. Degradation of Bis(4-Hydroxyphenyl)methane (bisphenol F) by Sphingobium yanoikuyae strain FM-2 isolated from river water. Appl Environ Microbiol 2008; 74:352-8. [PMID: 18024680 PMCID: PMC2223261 DOI: 10.1128/aem.01708-07] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Accepted: 11/06/2007] [Indexed: 11/20/2022] Open
Abstract
Three bacteria capable of utilizing bis(4-hydroxyphenyl)methane (bisphenol F [BPF]) as the sole carbon source were isolated from river water, and they all belonged to the family Sphingomonadaceae. One of the isolates, designated Sphingobium yanoikuyae strain FM-2, at an initial cell density of 0.01 (optical density at 600 nm) completely degraded 0.5 mM BPF within 9 h without any lag period under inductive conditions. Degradation assays of various bisphenols revealed that the BPF-metabolizing system of strain FM-2 was effective only on the limited range of bisphenols consisting of two phenolic rings joined together through a bridging carbon without any methyl substitution on the rings or on the bridging structure. A BPF biodegradation pathway was proposed on the basis of metabolite production patterns and identification of the metabolites. The initial step of BPF biodegradation involves hydroxylation of the bridging carbon to form bis(4-hydroxyphenyl)methanol, followed by oxidation to 4,4'-dihydroxybenzophenone. The 4,4'-dihydroxybenzophenone appears to be further oxidized by the Baeyer-Villiger reaction to 4-hydroxyphenyl 4-hydroxybenzoate, which is then cleaved by oxidation to form 4-hydroxybenzoate and 1,4-hydroquinone. Both of the resultant simple aromatic compounds are mineralized.
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Affiliation(s)
- Daisuke Inoue
- Division of Sustainable Energy and Environmental Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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31
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Szárics E, Kovács R, Hajós F, Kardos J. Ca2+ ion accumulation precedes formation of O2-* in isolated brain mitochondria. Neuroreport 2007; 17:1767-71. [PMID: 17164661 DOI: 10.1097/wnr.0b013e32800fefb8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The relationship between mitochondrial Ca2+ accumulation and reactive oxygen species formation is studied by means of fast kinetics with fluorescence detection. Succinate or elevated [Na+] and [Ca2+] provided alternative conditions for induction of reactive oxygen species in isolated rat cerebrocortical mitochondria. Depending on Na+/Ca2+ exchanger and superoxide dismutase activities, formation of reactive oxygen species in mitochondria exposed to elevated [Na+] and [Ca2+] levels was characterized by t(1/2) = 12.3+/-2.9 ms. Production of reactive oxygen species by xanthine oxidase followed a similar time course. Both the processes were blocked by para-benzoquinone, indicating the primary formation of O2-*. Substantial increase in mitochondrial O2-*. was observed at [Ca2+] > or = 2.5 microM. Mitochondrial Ca2+ accumulation obeyed similar [Ca2+] dependence but shorter t(1/2) (2.5+/-0.3 ms), providing kinetic evidence for Ca2+ accumulation-dependent primary formation of O2-* in brain mitochondria.
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Affiliation(s)
- Eva Szárics
- Department of Neurochemistry, Institute of Biomolecular Chemistry, Chemical Research Centre, Hungarian Academy of Sciences, Budapest, Hungary
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32
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Mandal S, Kazmi NH, Sayre LM. Ligand dependence in the copper-catalyzed oxidation of hydroquinones. Arch Biochem Biophys 2005; 435:21-31. [PMID: 15680903 DOI: 10.1016/j.abb.2004.11.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2004] [Revised: 11/25/2004] [Indexed: 11/29/2022]
Abstract
Transition metal-mediated oxidation of hydroquinones is an important physiologic reaction, and copper(II) effectively catalyzes the reaction in phosphate-buffered saline (PBS). Studies reported herein in phosphate buffer alone demonstrate that copper(II) is an ineffective catalyst in the absence of coordinating ligands, but that 1,10-phenanthroline and histamine facilitate the copper(II)-mediated oxidation of hydroquinone and its 2,5- and 2,6-di-tert-butyl analogs to the corresponding benzoquinones. The high concentration of chloride in PBS is the key element that allows copper(II) to work in this system. Although the bis-bathocuproine disulfonate complex of Cu(II), (BC)(2)Cu(II), is a strong stoichiometric oxidant, stoichiometric amounts of copper(II) in the presence of ligands other than BC oxidize hydroquinones very slowly under anaerobic conditions. Thus, the rapid copper(II)-catalyzed reaction operating aerobically does not involve a simple ping-pong reduction of copper(II) to copper(I) by hydroquinone and reoxidation of copper(I) by O(2).
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Affiliation(s)
- Subrata Mandal
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA
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33
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Alegría AE, Sanchez-Cruz P, Rivas L. Alkaline-earth cations enhance ortho-quinone-catalyzed ascorbate oxidation. Free Radic Biol Med 2004; 37:1631-9. [PMID: 15477014 DOI: 10.1016/j.freeradbiomed.2004.07.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Revised: 06/29/2004] [Accepted: 07/22/2004] [Indexed: 10/26/2022]
Abstract
Ortho-quinones 1,10-phenanthroquinone and beta-lapachone but not para-quinones naphthazarin (NZQ) and 1,4-naphthoquinone enhance ascorbate oxidation in the presence of MgCl(2) and CaCl(2) at constant ionic strength. Alkaline-earth cation chelation is observed for the ortho-semiquinones but not for the para-semiquinones, while no interaction between these quinones (with the exception of NZQ) or ascorbate and these salts was detected, suggesting that semiquinone-metal complexes are responsible for the catalytic action on ascorbate oxidation of these metal salts in the presence of these ortho-quinones. Thus, redox cycling efficiency of the quinones under study here, in the presence of ascorbate, depends not only on the quinone redox potential but also on the semiquinone ability to chelate alkaline-earth cations.
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Affiliation(s)
- Antonio E Alegría
- Department of Chemistry, University of Puerto Rico at Humacao, CUH Station, Humacao, PR 00791.
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34
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Munday R. Activation and Detoxification of Naphthoquinones by NAD(P)H: Quinone Oxidoreductase. Methods Enzymol 2004; 382:364-80. [PMID: 15047112 DOI: 10.1016/s0076-6879(04)82020-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- Rex Munday
- AgResearch, Ruakura Agricultural Research Centre, Hamilton, New Zealand
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35
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Audi SH, Zhao H, Bongard RD, Hogg N, Kettenhofen NJ, Kalyanaraman B, Dawson CA, Merker MP. Pulmonary arterial endothelial cells affect the redox status of coenzyme Q0. Free Radic Biol Med 2003; 34:892-907. [PMID: 12654478 DOI: 10.1016/s0891-5849(03)00025-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The pulmonary endothelium is capable of reducing certain redox-active compounds as they pass from the systemic venous to the arterial circulation. This may have important consequences with regard to the pulmonary and systemic disposition and biochemistry of these compounds. Because quinones comprise an important class of redox-active compounds with a range of physiological, toxicological, and pharmacological activities, the objective of the present study was to determine the fate of a model quinone, coenzyme Q0 (Q), added to the extracellular medium surrounding pulmonary arterial endothelial cells in culture, with particular attention to the effect of the cells on the redox status of Q in the medium. Spectrophotometry, electron paramagnetic resonance (EPR), and high-performance liquid chromatography (HPLC) demonstrated that, when the oxidized form Q is added to the medium surrounding the cells, it is rapidly converted to its quinol form (QH2) with a small concentration of semiquinone (Q*-) also detectable. The isolation of cell plasma membrane proteins revealed an NADH-Q oxidoreductase located on the outer plasma membrane surface, which apparently participates in the reduction process. In addition, once formed the QH2 undergoes a cyanide-sensitive oxidation by the cells. Thus, the actual rate of Q reduction by the cells is greater than the net QH2 output from the cells.
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Affiliation(s)
- Said H Audi
- Department of Biomedical Engineering, Marquette University, Milwaukee, WI, USA
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36
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Moridani MY, Cheon SS, Khan S, O'Brien PJ. Metabolic activation of 3-hydroxyanisole by isolated rat hepatocytes. Chem Biol Interact 2003; 142:317-33. [PMID: 12453669 DOI: 10.1016/s0009-2797(02)00125-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A tyrosinase-directed therapeutic approach for malignant melanoma therapy uses the depigmenting phenolic agents such as 4-hydroxyanisole (4-HA) to form cytotoxic o-quinones. However, renal and hepatic toxicity was reported as side effects in a recent 4-HA clinical trial. In search of novel therapeutics, the cytotoxicity of the isomers 4-HA, 3-HA and 2-HA were investigated. In the following, the order of the HAs induced hepatotoxicity in mice, as measured by increased in vivo plasma transaminase activity, or in isolated rat hepatocytes, as measured by trypan blue exclusion, was 3-HA > 2-HA > 4-HA. Hepatocyte GSH depletion preceded HA induced cytotoxicity and a 4-MC-SG conjugate was identified by LC/MS/MS mass spectrometry analysis when 3-HA was incubated with NADPH/microsomes/GSH. 3-HA induced hepatocyte GSH depletion or GSH depletion when 3-HA was incubated with NADPH/microsomes was prevented by CYP 2E1 inhibitors. Dicumarol (an NAD(P)H: quinone oxidoreductase inhibitor) potentiated 3-HA- or 4-methoxycatechol (4-MC) induced toxicity whereas sorbitol (an NADH generating nutrient) greatly prevented cytotoxicity indicating a quinone-mediated cytotoxic mechanism. Ethylendiamine (an o-quinone trap) largely prevented 3-HA and 4-MC-induced cytotoxicity indicating that o-quinone was involved in cytotoxicity. Dithiothreitol (DTT) greatly reduced 3-HA and 4-MC induced toxicity. The ferric chelator deferoxamine slightly decreased 3-HA and 4-MC induced cytotoxicity whereas the antioxidants pyrogallol or TEMPOL greatly prevented the toxicity suggesting that oxidative stress contributed to 3-HA induced cytotoxicity. In summary, ring hydroxylation but not O-demethylation/epoxidation seems to be the bioactivation pathway for 3-HA in rat liver. The cytotoxic mechanism for 3-HA and its metabolite 4-MC likely consists cellular protein alkylation and oxidative stress. These results suggest that 3-HA is not suitable for treatment of melanoma.
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Affiliation(s)
- Majid Y Moridani
- Faculty of Pharmacy, University of Toronto, 19 Russell Street, Toronto, Ont, Canada M5S 2S2
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Moridani MY, Cheon SS, Khan S, O'Brien PJ. Metabolic activation of 4-hydroxyanisole by isolated rat hepatocytes. Drug Metab Dispos 2002; 30:1063-9. [PMID: 12228181 DOI: 10.1124/dmd.30.10.1063] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A tyrosinase-directed therapeutic approach for treating malignant melanoma uses depigmenting phenolic prodrugs such as 4-hydroxyanisole (4-HA) for oxidation by melanoma tyrosinase to form cytotoxic o-quinones. However, in a recent clinical trial, both renal and hepatic toxicity were reported as side effects of 4-HA therapy. In the following, 4-HA (200 mg/kg i.p.) administered to mice caused a 7-fold increase in plasma transaminase toxicity, an indication of liver toxicity. Furthermore, 4-HA induced-cytotoxicity toward isolated hepatocytes was preceded by glutathione (GSH) depletion, which was prevented by cytochrome p450 inhibitors that also partly prevented cytotoxicity. The 4-HA metabolite formed by NADPH/microsomes and GSH was identified as a hydroquinone mono-glutathione conjugate. GSH-depleted hepatocytes were much more prone to cytotoxicity induced by 4-HA or its reactive metabolite hydroquinone (HQ). Dicumarol (an NAD(P)H/quinone oxidoreductase inhibitor) also potentiated 4-HA- or HQ-induced toxicity whereas sorbitol, an NADH-generating nutrient, prevented the cytotoxicity. Ethylenediamine (an o-quinone trap) did not prevent 4-HA-induced cytotoxicity, which suggests that the cytotoxicity was not caused by o-quinone as a result of 4-HA ring hydroxylation. Deferoxamine and the antioxidant pyrogallol/4-hydroxy-2,2,6,6-tetramethylpiperidene-1-oxyl (TEMPOL) did not prevent 4-HA-induced cytotoxicity, therefore excluding oxidative stress as a cytotoxic mechanism for 4-HA. A negligible amount of formaldehyde was formed when 4-HA was incubated with rat microsomal/NADPH. These results suggest that the 4-HA cytotoxic mechanism involves alkylation of cellular proteins by 4-HA epoxide or p-quinone rather than involving oxidative stress.
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Affiliation(s)
- M Y Moridani
- Department of Pediatric Laboratory Medicine, Hospital for Sick Children and Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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Romsted LS, Zhang J. Kinetic method for determining antioxidant distributions in model food emulsions: distribution constants of t-butylhydroquinone in mixtures of octane, water, and a nonionic emulsifier. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2002; 50:3328-3336. [PMID: 12010006 DOI: 10.1021/jf011711z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The absence of reliable estimates of distributions of antioxidants in food emulsions hinders the development of a useful method for comparing the efficiencies of antioxidants. Here we describe the application of a pseudophase kinetic model, originally developed for homogeneous microemulsions, to the determination of distribution constants of tert-butylhydroquinone, TBHQ, in a fluid, opaque, model food emulsion composed of the nonionic emulsifier C(12)E(6), octane, and water. This kinetic method should be applicable to a wide variety of charged and uncharged antioxidants in emulsions composed of charged and uncharged emulsifiers. The distribution constants for partitioning of TBHQ between the oil and surfactant film regions, K(O)(I), and the aqueous and surfactant film regions, K(W)(I), were obtained by fitting changes in first-order rate constants, k(obs), with emulsifier volume fraction for the reaction of 4-hexadecyl-2,6-dimethylbenzenediazonium ion, 16-ArN(2)(+), with TBHQ. The rate of formation of the reduced arene product hexadecyl-2,6-dimethylbenzene, 16-ArH, was followed by HPLC. About 90% of the TBHQ is in the surfactant film at about 2% volume fraction of C(12)E(6), which suggests that this region may be the primary site of antioxidant activity for neutral phenolic antioxidants.
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Affiliation(s)
- Laurence S Romsted
- Center for Advanced Food Technology and Department of Chemistry and Chemical Biology, Wright and Rieman Laboratories, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, USA.
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Alegría AE, Santiago G, Lópes M, Rosario BI, Cordones E. Role of membrane charge and semiquinone structure on naphthosemiquinone derivatives and 1,4-benzosemiquinone disproportionation and membrane-buffer distribution coefficients. Free Radic Res 2001; 35:529-41. [PMID: 11767411 DOI: 10.1080/10715760100301541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Semiquinone membrane/buffer partition coefficients have been determined for 1,2-naphthosemiquinone (ONQ.-), 1,4-naphthosemiquinone (NQ.-) and two of its hydroxylated derivatives, 5,8-dihydroxy-1,4-naphthosemiquinone (NZQ.-) and 5-hydroxy-1,4-naphthosemiquinone (JQ.-) as a function of membrane charge in multilamellar vesicles of phosphatidylcholine (PC) and equimolar mixtures of this lipid and phosphatidic acid (PC:PA) and cetyltrimethylammonium bromide (PC:CTAB) at physiological pH with the exception of values corresponding to PC:PA mixtures which were obtained at pH 9. These coefficients follow the order PC:PA < PC < PC:CTAB in agreement with the negative charge of the semiquinones. The disproportionation equilibria of the naphthosemiquinone derivatives are shifted to the semiquinone in the presence of neutral and positive membranes, being more pronounced in the latter. However, very low partition coefficients as well as small shifts in the semiquinone disproportionation equilibrium were observed for ONQ.- as compared to the other semiquinones. No partition of 1,4-benzosemiquinone (BQ.-) into the lipid phase was detected for either charged or neutral lipid membranes. The presence of lipid membranes decreases the BQ.- equilibrium concentration in the presence of all the types of membranes considered here.
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Affiliation(s)
- A E Alegría
- Department of Chemistry, University of Puerto Rico at Humacao, CUH Station, Humacao, PR 00791, Puerto Rico.
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Munday R. Concerted action of DT-diaphorase and superoxide dismutase in preventing redox cycling of naphthoquinones: an evaluation. Free Radic Res 2001; 35:145-58. [PMID: 11697195 DOI: 10.1080/10715760100300691] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
It has been suggested that the enzymes DT-diaphorase and superoxide dismutase act in concert to prevent redox cycling of naphthoquinones and thus protect against the toxic effects of such substances. Little is known, however, about the scope of this process or the conditions necessary for its operation. In the presence of low levels of DT-diaphorase, 2-methyl-1,4-naphthoquinone was found to undergo redox cycling. This was very effectively inhibited by SOD, and in the presence of both enzymes the hydroquinone was maintained in the reduced form. The inhibitory effect of the enzyme combination was overcome, however, at high concentrations of the quinone, or by small increases in pH. Furthermore, redox cycling was re-established by addition of haemoproteins such as cytochrome c and methaemoglobin. DT-diaphorase and SOD strongly inhibited redox cycling by 2,3-dimethyl- and 2,3-dimethoxy-1,4-naphthoquinone, but not that of 2-hydroxy-, 5-hydroxy- or 2-amino-1,4-naphthoquinone. Inhibition of redox cycling by a combination of DT-diaphorase and SOD is therefore not applicable to all naphthoquinone derivatives, and when it does occur, it may be overwhelmed at high quinone concentrations, and it may not operate under slightly alkaline conditions or in the presence of tissue components capable of initiating hydroquinone autoxidation.
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Affiliation(s)
- R Munday
- AgResearch, Ruakura Agricultural Research Centre, Private Bag 3123, Hamilton, New Zealand.
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Liochev SI, Fridovich I. The Oxidation of 3-Hydroxyanthranilic Acid by Cu,Zn Superoxide Dismutase: Mechanism and Possible Consequences. Arch Biochem Biophys 2001; 388:281-4. [PMID: 11368166 DOI: 10.1006/abbi.2001.2296] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cu,Zn SOD, but not Mn SOD, catalyzes the oxidation of 3-hydroxyanthranilic acid (3-HA) under aerobic conditions. In the absence of O2, the Cu(II) of the enzyme is reduced by 3-HA. One plausible mechanism involves the reduction of the active site Cu(II) to Cu(I), which is then reoxidized by the O2- generated by autoxidation of the anthranilyl or other radicals on the pathway to cinnabarinate. We may call this the superoxide reductase, or SOR, mechanism. Another possibility invokes direct reoxidation of the active site Cu(I) by the anthranilyl, or other organic radicals, or by the peroxyl radicals generated by addition of O2 to these organic radicals. Such oxidations catalyzed by Cu,Zn SOD could account for the deleterious effects of the mutant Cu,Zn SODs associated with familial amyotrophic lateral sclerosis and of the overproduction or overadministration of wild-type Cu,Zn SOD.
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Affiliation(s)
- S I Liochev
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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McLean MR, Twaroski TP, Robertson LW. Redox cycling of 2-(x'-mono, -di, -trichlorophenyl)- 1, 4-benzoquinones, oxidation products of polychlorinated biphenyls. Arch Biochem Biophys 2000; 376:449-55. [PMID: 10775433 DOI: 10.1006/abbi.2000.1754] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Polychlorinated biphenyl (PCB) preparations are complete liver carcinogens in rodents and efficacious promoters in two-stage hepatocarcinogenesis. Cytochrome P450 isozymes catalyze the oxidation of PCBs to mono- and dihydroxy metabolites. The potential for further enzymatic or nonenzymatic oxidation of ortho- and para-dihydroxy PCB metabolites to (semi)quinones raises the possibility that redox cycling involving reactive oxygen species may be involved in PCB toxicity. Seven synthetic 2-(x'-chlorophenyl)-1, 4-benzoquinones (containing one to three chlorines) were investigated for their participation in oxidation-reduction reactions by following the oxidation of NADPH. These observations were made: (i) NADPH alone directly reduced all quinones but only 2-(2'-chlorophenyl)- and 2-(4'-chlorophenyl)-1,4-benzoquinone supported NADPH consumption beyond that required to quantitatively reduce the quinone. (ii) For all quinones, superoxide dismutase increased NADPH oxidation in excess of the amount of quinone, demonstrating the participation of the superoxide radical. (iii) The presence of microsomal enzymes from rat liver increased the rate of NADPH consumption, but only 2-(2'-chlorophenyl)- and 2-(4'-chlorophenyl)-1,4-benzoquinone autoxidized. (iv) The combination of superoxide dismutase with microsomal enzymes accelerated autoxidation from 1.6- to 6.8-fold higher than that found in the absence of microsomal protein. These data support the concept that in the absence of microsomal protein, there occurs a two-electron reduction of the quinone by NADPH to the corresponding hydroquinone that comproportionates with the large reservoir of quinone to initiate autoxidation. In the presence of microsomes, enzymatic one-electron reduction generates a semiquinone radical whose autoxidation with oxygen propagates the redox cycle. These results show the potential of some 2-(x'-chlorophenyl)-1, 4-benzoquinones to initiate the wasteful loss of NADPH.
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Affiliation(s)
- M R McLean
- Graduate Center for Toxicology, University of Kentucky, Lexington, Kentucky 40536, USA
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Soto-Otero R, Méndez-Alvarez E, Hermida-Ameijeiras A, Muñoz-Patiño AM, Labandeira-Garcia JL. Autoxidation and neurotoxicity of 6-hydroxydopamine in the presence of some antioxidants: potential implication in relation to the pathogenesis of Parkinson's disease. J Neurochem 2000; 74:1605-12. [PMID: 10737618 DOI: 10.1046/j.1471-4159.2000.0741605.x] [Citation(s) in RCA: 240] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
6-Hydroxydopamine (6-OHDA) is a dopaminergic neurotoxin putatively involved in the pathogenesis of Parkinson's disease (PD). Its neurotoxicity has been related to the production of reactive oxygen species. In this study we examine the effects of the antioxidants ascorbic acid (AA), glutathione (GSH), cysteine (CySH), and N-acetyl-CySH (NAC) on the autoxidation and neurotoxicity of 6-OHDA. In vitro, the autoxidation of 6-OHDA proceeds rapidly with the formation of H2O2 and with the participation of the H2O2 produced in the reaction. The presence of AA induced a reduction in the consumption of O2 during the autoxidation of 6-OHDA and a negligible presence of the p-quinone, which demonstrates the efficiency of AA to act as a redox cycling agent. The presence of GSH, CySH, and NAC produced a significant reduction in the autoxidation of 6-OHDA. In vivo, the presence of sulfhydryl antioxidants protected against neuronal degeneration in the striatum, which was particularly remarkable in the case of CySH and was attributed to its capacity to remove the H2O2 produced in the autoxidation of 6-OHDA. These results corroborate the involvement of oxidative stress as the major mechanism in the neurotoxicity of 6-OHDA and the putative role of CySH as a scavenger in relation to PD.
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Affiliation(s)
- R Soto-Otero
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Santiago de Compostela, Spain.
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Munday R. Autoxidation of naphthohydroquinones: effects of pH, naphthoquinones and superoxide dismutase. Free Radic Res 2000; 32:245-53. [PMID: 10730823 DOI: 10.1080/10715760000300251] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The rates of autoxidation of a number of pure naphthohydroquinones have been determined, and the effects of pH, superoxide dismutase (SOD) and of the parent naphthoquinone on the oxidation rates have been investigated. Most compounds were slowly oxidised in acid solution with the rates increasing with increasing pH, although 2-hydroxy-, 2-hydroxy-3-methyl- and 2-amino-1,4-naphthohydroquinone were rapidly oxidised at pH 5 and the rates of oxidation of these substances were comparatively unresponsive to changes in pH. At pH 7.4, autoxidation rates decreased in the order 2,3-dichloro-1,4-naphthohydroquinone > 5-hydroxy > 2-bromo > 2-hydroxy-3-methyl > 2-amino > 2-hydroxy > 2-methoxy > 2,3-dimethoxy > 2,3-dimethyl > 2-methyl > unsubstituted hydroquinone. The autoxidation rates of the alkyl, alkoxy, hydroxy and amino derivatives were decreased in the presence of SOD, but this enzyme had no effect on the rate of autoxidation of the 2,3-dichloro and 2-bromo derivatives while that of the 5-hydroxy derivative was increased. The rates of autoxidation of all compounds except the halogen derivatives and 5-hydroxy-1,4-naphthohydroquinone were increased by addition of the parent naphthoquinone, and quinone addition partially or completely overcame the inhibitory effect of SOD. There is evidence that the reduction of quinones to hydroquinones in vivo may lead either to detoxification or to activation. This may be due to differences in the rate or mechanism of autoxidation of the hydroquinones that are formed, and the data gained in this study will provide a framework for testing this possibility.
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Affiliation(s)
- R Munday
- AgResearch, Ruakura Agricultural Research Centre, Hamilton, New Zealand.
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Li Y, Kuppusamy P, Zweier JL, Trush MA. ESR evidence for the generation of reactive oxygen species from the copper-mediated oxidation of the benzene metabolite, hydroquinone: role in DNA damage. Chem Biol Interact 1995; 94:101-20. [PMID: 7828218 DOI: 10.1016/0009-2797(94)03326-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In previous studies, we observed that Cu(II) strongly induces the oxidation of hydroquinone (HQ), producing benzoquinone and H2O2 through a Cu(II)/Cu(I) redox cycle mechanism. The oxidation of HQ by Cu(II) also results in plasmid DNA cleavage. In this study, using ESR spectroscopy we have investigated whether this chemical-metal redox system can generate reactive oxygen species which induce DNA damage. In order to set the stage for the ESR experiments and the inhibitors to be used in these experiments, some preliminary O2 consumption and plasmid DNA cleavage experiments were performed. Mixing 100 microM HQ with 10 microM Cu(II) in phosphate-buffered saline (PBS) resulted in a marked consumption of O2 and the concomitant generation of H2O2, and extensive DNA degradation in chi X-174 RF I DNA. The presence of superoxide dismutase (SOD) or mannitol did not affect either the O2 consumption, H2O2 generation or DNA damage. In contrast, the Cu(I) chelators, bathocuproinedisulfonic acid (BCS) and glutathione (GSH), extensively inhibited the HQ/Cu(II)-mediated O2 consumption and DNA damage. The presence of catalase also prevented the DNA damage. Although the HQ/Cu(II)-mediated O2 consumption increased in the presence of azide, azide markedly inhibited the HQ/Cu(II)-induced DNA degradation, resulting in primarily open circles. Using ESR spectroscopy, it was observed that Cu(II) strongly mediated the formation of semiquinone anion radicals from HQ in PBS, which could be blocked by BCS. alpha-(4-Pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN)-spin trapping experiments showed that the interaction of HQ with Cu(II) produced 4-POBN-CH3 and 4-POBN-CH(OH)CH3 adducts in the presence of dimethyl sulfoxide (DMSO) and ethanol, respectively, suggesting that hydroxyl radical or an equivalent reactive intermediate is generated from the HQ/Cu(II) system. The presence of catalase, BCS or GSH but not SOD completely prevented the formation of 4-POBN-CH3 adduct from the HQ/Cu(II) plus 4-POBN/DMSO system. This indicates that both H2O2 and Cu(I) are critical for the formation of reactive oxygen from the HQ/Cu(II) system. Anaerobic conditions induced an approximately 85% decrease in the formation of 4-POBN-CH3 adduct. Reactive oxygen scavenger experiments showed that the formation of the 4-POBN-CH3 adduct was significantly inhibited by azide but not by mannitol. Overall, the above results indicate that through a copper-redox cycling mechanism the copper-mediated oxidation of HQ generates reactive oxygen species which may participate in DNA damage.
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Affiliation(s)
- Y Li
- Department of Environmental Health Sciences, Johns Hopkins Medical Institutions, Baltimore, MD 21205
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