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Angelé-Martínez C, Goncalves LCP, Premi S, Augusto FA, Palmatier MA, Amar SK, Brash DE. Triplet-Energy Quenching Functions of Antioxidant Molecules. Antioxidants (Basel) 2022; 11:antiox11020357. [PMID: 35204239 PMCID: PMC8868474 DOI: 10.3390/antiox11020357] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/01/2022] [Accepted: 02/08/2022] [Indexed: 01/27/2023] Open
Abstract
UV-like DNA damage is created in the dark by chemiexcitation, in which UV-activated enzymes generate reactive oxygen and nitrogen species that create a dioxetane on melanin. Thermal cleavage creates an electronically excited triplet-state carbonyl whose high energy transfers to DNA. Screening natural compounds for the ability to quench this energy identified polyenes, polyphenols, mycosporine-like amino acids, and related compounds better known as antioxidants. To eliminate false positives such as ROS and RNS scavengers, we then used the generator of triplet-state acetone, tetramethyl-1,2-dioxetane (TMD), to excite the triplet-energy reporter 9,10-dibromoanthracene-2-sulfonate (DBAS). Quenching measured as reduction in DBAS luminescence revealed three clusters of 50% inhibitory concentration, ~50 μM, 200–500 μM, and >600 μM, with the former including sorbate, ferulic acid, and resveratrol. Representative triplet-state quenchers prevented chemiexcitation-induced “dark” cyclobutane pyrimidine dimers (dCPD) in DNA and in UVA-irradiated melanocytes. We conclude that (i) the delocalized pi electron cloud that stabilizes the electron-donating activity of many common antioxidants allows the same molecule to prevent an electronically excited species from transferring its triplet-state energy to targets such as DNA and (ii) the most effective class of triplet-state quenchers appear to operate by energy diversion instead of electron donation and dissipate that energy by isomerization.
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Affiliation(s)
- Carlos Angelé-Martínez
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA; (C.A.-M.); (L.C.P.G.); (S.P.); (F.A.A.); (M.A.P.); (S.K.A.)
| | - Leticia Christina Pires Goncalves
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA; (C.A.-M.); (L.C.P.G.); (S.P.); (F.A.A.); (M.A.P.); (S.K.A.)
| | - Sanjay Premi
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA; (C.A.-M.); (L.C.P.G.); (S.P.); (F.A.A.); (M.A.P.); (S.K.A.)
| | - Felipe A. Augusto
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA; (C.A.-M.); (L.C.P.G.); (S.P.); (F.A.A.); (M.A.P.); (S.K.A.)
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo 05508-900, SP, Brazil
| | - Meg A. Palmatier
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA; (C.A.-M.); (L.C.P.G.); (S.P.); (F.A.A.); (M.A.P.); (S.K.A.)
| | - Saroj K. Amar
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA; (C.A.-M.); (L.C.P.G.); (S.P.); (F.A.A.); (M.A.P.); (S.K.A.)
| | - Douglas E. Brash
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA; (C.A.-M.); (L.C.P.G.); (S.P.); (F.A.A.); (M.A.P.); (S.K.A.)
- Department of Dermatology, Yale School of Medicine, New Haven, CT 06520-8059, USA
- Yale Cancer Center, Yale School of Medicine, New Haven, CT 06520-8028, USA
- Correspondence:
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Kumar S, Mitra A, Halder D. Centella asiatica leaf mediated synthesis of silver nanocolloid and its application as filler in gelatin based antimicrobial nanocomposite film. Lebensm Wiss Technol 2017. [DOI: 10.1016/j.lwt.2016.06.061] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Krupkova O, Ferguson SJ, Wuertz-Kozak K. Stability of (−)-epigallocatechin gallate and its activity in liquid formulations and delivery systems. J Nutr Biochem 2016; 37:1-12. [DOI: 10.1016/j.jnutbio.2016.01.002] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/20/2016] [Accepted: 01/28/2016] [Indexed: 12/24/2022]
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Pignitter M, Stolze K, Jirsa F, Gille L, Goodman BA, Somoza V. Effect of Copper on Fatty Acid Profiles in Non- and Semifermented Teas Analyzed by LC-MS-Based Nontargeted Screening. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:8519-8526. [PMID: 26335726 DOI: 10.1021/acs.jafc.5b02792] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Unsaturated fatty acids are well-known precursors of aroma compounds, which are considered important for green tea quality. Due to the known copper-induced oxidation of unsaturated fatty acids and the broad variability of the amount of copper present in tea infusions, this paper investigates the influence of copper, added at a nontoxic concentration (300 μM) to non- and semifermented teas, on the degradation of fatty acids and fatty acid hydroperoxides thereof. The abundance of fatty acids in green and oolong tea was determined by means of a nontargeted approach applying high-resolution MS/MS. As a result, most of the fatty acids in green and oolong tea were already oxidized prior to copper addition. Addition of 300 μM CuSO4 to the oolong tea sample resulted in a decrease of 13-hydroperoxy-9Z,11E-octadecadienoic acid, an important flavor precursor, from 0.12 ± 0.02 to 0.05 ± 0.01 μM (p = 0.035), and other oxidized fatty acids decreased as well. However, copper-induced degradation of oxidized fatty acids was less pronounced in green tea compared to oolong tea, most likely due to the formation of copper complexes with low-molecular-weight compounds as evidenced by electron paramagnetic resonance spectroscopy.
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Affiliation(s)
- Marc Pignitter
- Department of Nutritional and Physiological Chemistry, Faculty of Chemistry, University of Vienna , 1090 Vienna, Austria
| | - Klaus Stolze
- Institute of Animal Nutrition and Functional Plant Compounds, University of Veterinary Medicine Vienna , 1210 Vienna, Austria
| | - Franz Jirsa
- Department of Inorganic Chemistry, University of Vienna , 1090 Vienna, Austria
- Department of Zoology, University of Johannesburg , P.O. Box 524, Auckland Park, 2006 South Africa
| | - Lars Gille
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine Vienna , 1210 Vienna, Austria
| | - Bernard A Goodman
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University , 530004 Nanning, Guangxi, China
| | - Veronika Somoza
- Department of Nutritional and Physiological Chemistry, Faculty of Chemistry, University of Vienna , 1090 Vienna, Austria
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Fan K, Luo X, Ping J, Tang W, Wu J, Ying Y, Zhou Q. Sensitive determination of (-)-epigallocatechin gallate in tea infusion using a novel ionic liquid carbon paste electrode. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:6333-6340. [PMID: 22676480 DOI: 10.1021/jf300498e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This paper investigates the electrocatalytic oxidation of (-)-epigallocatechin gallate (EGCG), the main monomer flavanol found in green tea, with a novel ionic liquid, n-octylpyridinium hexafluorophosphate (OPFP) carbon paste electrode (CPE). Due to the natural viscosity and high conductivity of OPFP, this novel OPFP-CPE exhibited very attractive properties, such as high stability and electrochemical reactivity, low background current, and wide electrochemical window. Therefore, this electrode is a very good alternative to traditional chemically modified electrodes because the electrocatalytic effect can achieved without any further electrode modification. Comparative experiments were carried out using CPE and a glassy carbon electrode (GCE). With OPFP-CPE, highly reproducible and well-defined cyclic voltammograms were obtained for EGCG. Under optimal experimental conditions, the peak current of differential pulse voltammetry (DPV) response increased linearly with EGCG concentration over the range of 5.0 × 10(-7)-1.25 × 10(-5) M. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.32 × 10(-7) and 4.35 × 10(-7) M, respectively. The method was applied to the determination of EGCG in green tea infusion samples, and the recovery of the spiked EGCG to the diluted (10-fold) tea extract was from 87.62 to 99.51%.
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Affiliation(s)
- Kai Fan
- College of Biosystems Engineering and Food Science, Zhejiang University , Hangzhou 310058, People's Republic of China
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Goodman BA, Ferreira Severino J, Pirker KF. Reactions of green and black teas with Cu(II). Food Funct 2011; 3:399-409. [PMID: 22159216 DOI: 10.1039/c1fo10086f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Electron paramagnetic resonance (EPR) measurements of the products of reactions between Cu(II) and samples of green and black teas showed spectral components from at least six different Cu(II) complexes with both tea types. Several of these complexes were common to both teas in spite of major differences in their polyphenol compositions. The pH range observed for complex formation, and the total signal intensity in the pH range 4-8, were greatly different from those for the reactions of Cu(II) with (-)-epigallocatechin gallate and gallic acid, the main polyphenols responsible for the free radical signals observed during oxidation of these beverages. Components with spectral parameters similar to those of Cu(II) complexes with theanine, the major amino acid in tea, may contribute to two of the spectra recorded under acidic conditions. However, the initial complexes formed at the lowest pH values investigated are still unidentified. EPR spectra with parameters consistent with Cu(II) polyphenol complexes were only observed under alkaline conditions, thus suggesting that components of tea other than polyphenols might be more important in reactions with copper, and possibly other transition metals, in solutions under physiological conditions.
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Affiliation(s)
- B A Goodman
- Health and Environment Department, Business Unit of Environmental Resources and Technologies, Austrian Institute of Technology GmbH, A-2444, Seibersdorf, Austria.
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Schinko T, Berger H, Lee W, Gallmetzer A, Pirker K, Pachlinger R, Buchner I, Reichenauer T, Güldener U, Strauss J. Transcriptome analysis of nitrate assimilation in Aspergillus nidulans reveals connections to nitric oxide metabolism. Mol Microbiol 2010; 78:720-38. [PMID: 20969648 PMCID: PMC3020322 DOI: 10.1111/j.1365-2958.2010.07363.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2010] [Indexed: 01/08/2023]
Abstract
Nitrate is a dominant form of inorganic nitrogen (N) in soils and can be efficiently assimilated by bacteria, fungi and plants. We studied here the transcriptome of the short-term nitrate response using assimilating and non-assimilating strains of the model ascomycete Aspergillus nidulans. Among the 72 genes positively responding to nitrate, only 18 genes carry binding sites for the pathway-specific activator NirA. Forty-five genes were repressed by nitrate metabolism. Because nirA(-) strains are N-starved at nitrate induction conditions, we also compared the nitrate transcriptome with N-deprived conditions and found a partial overlap of differentially regulated genes between these conditions. Nitric oxide (NO)-metabolizing flavohaemoglobins were found to be co-regulated with nitrate assimilatory genes. Subsequent molecular characterization revealed that the strongly inducible FhbA is required for full activity of nitrate and nitrite reductase enzymes. The co-regulation of NO-detoxifying and nitrate/nitrite assimilating systems may represent a conserved mechanism, which serves to neutralize nitrosative stress imposed by an external NO source in saprophytic and pathogenic fungi. Our analysis using membrane-permeable NO donors suggests that signalling for NirA activation only indirectly depends on the nitrate transporters NrtA (CrnA) and NrtB (CrnB).
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Affiliation(s)
- Thorsten Schinko
- Fungal Genetics and Genomics Unit, Department of Applied Genetics and Cell Biology, Austrian Institute of Technology and BOKU University ViennaMuthgasse 18, 1190 Vienna, Austria
| | - Harald Berger
- Fungal Genetics and Genomics Unit, Department of Applied Genetics and Cell Biology, Austrian Institute of Technology and BOKU University ViennaMuthgasse 18, 1190 Vienna, Austria
| | - Wanseon Lee
- Institute of Bioinformatics and Systems Biology, Helmholtz Zentrum München85764 Neuherberg, Germany
| | - Andreas Gallmetzer
- Fungal Genetics and Genomics Unit, Department of Applied Genetics and Cell Biology, Austrian Institute of Technology and BOKU University ViennaMuthgasse 18, 1190 Vienna, Austria
| | | | - Robert Pachlinger
- Fungal Genetics and Genomics Unit, Department of Applied Genetics and Cell Biology, Austrian Institute of Technology and BOKU University ViennaMuthgasse 18, 1190 Vienna, Austria
| | - Ingrid Buchner
- Fungal Genetics and Genomics Unit, Department of Applied Genetics and Cell Biology, Austrian Institute of Technology and BOKU University ViennaMuthgasse 18, 1190 Vienna, Austria
| | | | - Ulrich Güldener
- Institute of Bioinformatics and Systems Biology, Helmholtz Zentrum München85764 Neuherberg, Germany
| | - Joseph Strauss
- Fungal Genetics and Genomics Unit, Department of Applied Genetics and Cell Biology, Austrian Institute of Technology and BOKU University ViennaMuthgasse 18, 1190 Vienna, Austria
- Institute of Bioinformatics and Systems Biology, Helmholtz Zentrum München85764 Neuherberg, Germany
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Detection of total phenol in green and black teas by flow injection system and unmodified screen printed electrode. Int J Anal Chem 2010; 2010:143714. [PMID: 21461407 PMCID: PMC3065041 DOI: 10.1155/2010/143714] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/28/2010] [Accepted: 12/10/2010] [Indexed: 11/17/2022] Open
Abstract
A flow injection system using an unmodified gold screen-printed electrode was employed for total phenol determination in black and green teas. In order to avoid passivation of the electrode surface due to the redox reaction, preoxidation of the sample was realized by hexacyanoferrate(III) followed by addition of an EDTA solution. The complex formed in the presence of EDTA minimizes or avoids polymerization of the oxidized phenols. The previously filtered tea sample and hexacyanoferrate(III) reagent were introduced simultaneously into two-carrier streams producing two reproducible zones. At confluence point, the pre-oxidation of the phenolic compounds occurs while this zone flows through the coiled reactor and receives the EDTA solution before phenol detection. The consumption of ferricyanide was monitorized at 360 mV versus Ag/AgCl and reflected the total amount of phenolic compounds present in the sample. Results were reported as gallic acid equivalents (GAEs). The proposed system is robust, versatile, environmentally-friendly (since the reactive is used only in the presence of the sample), and allows the analysis of about 35-40 samples per hour with detection limit = 1 mg/L without the necessity for surface cleaning after each measurement. Precise results are in agreement with those obtained by the Folin-Ciocalteu method.
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Severino JF, Goodman BA, Kay CWM, Stolze K, Tunega D, Reichenauer TG, Pirker KF. Free radicals generated during oxidation of green tea polyphenols: electron paramagnetic resonance spectroscopy combined with density functional theory calculations. Free Radic Biol Med 2009; 46:1076-88. [PMID: 19439236 DOI: 10.1016/j.freeradbiomed.2009.01.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2008] [Revised: 12/03/2008] [Accepted: 01/09/2009] [Indexed: 10/21/2022]
Abstract
Electron paramagnetic resonance spectroscopy and density functional theory calculations have been used to investigate the redox properties of the green tea polyphenols (GTPs) (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC), and (-)-epicatechin gallate (ECG). Aqueous extracts of green tea and these individual phenols were autoxidized at alkaline pH and oxidized by superoxide anion (O(2)(-)) radicals in dimethyl sulfoxide. Several new aspects of the free radical chemistry of GTPs were revealed. EGCG can be oxidized on both the B and the D ring. The B ring was the main oxidation site during autoxidation, but the D ring was the preferred site for O(2)(-) oxidation. Oxidation of the D ring was followed by structural degradation, leading to generation of a radical identical to that of oxidized gallic acid. Alkaline autoxidation of green tea extracts produced four radicals that were related to products of the oxidation of EGCG, EGC, ECG, and gallic acid, whereas the spectra from O(2)(-) oxidation could be explained solely by radicals generated from EGCG. Assignments of hyperfine coupling constants were made by DFT calculations, allowing the identities of the radicals observed to be confirmed.
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Reichenauer TG, Germida JJ. Phytoremediation of organic contaminants in soil and groundwater. CHEMSUSCHEM 2008; 1:708-717. [PMID: 18698569 DOI: 10.1002/cssc.200800125] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Phytoremediation is an emerging technology for the clean-up of sites contaminated with hazardous chemicals. The term phytoremediation refers to a number of technologies that use photoautotrophic vascular plants for the remediation of sites contaminated with inorganic and organic contaminants. Phytoremediation of organic contaminants can be organized by considering 1) the green liver concept, which elucidates the metabolism of contaminants in planta versus that of contaminants ex planta (e.g. rhizosphere), 2) processes that lead to complete degradation (mineralization) of contaminants as opposed to those that only lead to partial degradation or transformation, and 3) active plant uptake versus passive processes (e.g. sorption). Understanding of these processes needs an interdisciplinary approach involving chemists, biologists, soil scientists, and environmentalists. This Review presents the basic concepts of phytoremediation of organic contaminants in soil and groundwater using selected contaminants as examples.
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Affiliation(s)
- Thomas G Reichenauer
- Department of Environmental Research, Austrian Research Centers GmbH-ARC, Seibersdorf, 2444, Austria.
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