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Oxidation and degradation of (epi)gallocatechin gallate (EGCG/GCG) and (epi)catechin gallate (ECG/CG) in alkali solution. Food Chem 2023; 408:134815. [PMID: 36549155 DOI: 10.1016/j.foodchem.2022.134815] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 10/16/2022] [Accepted: 10/28/2022] [Indexed: 11/11/2022]
Abstract
The oxidative decomposition/degradation of two main tea flavanols, EGCG/GCG and ECG/CG, was studied in alkaline solution under ultrasonic-assisted thermal conditions. The study employed HPLC-ESI-ToF-MS to identify the products generated by atmospheric oxygen oxidation and various base-catalyzed reactions. Strong basic condition led to accelerated hydrolysis and oxidation of EGCG/GCG and ECG/CG and yielded gallic acid, de-galloyl flavanols and corresponding o-quinone derivatives. Meanwhile, peroxidation or base-catalyzed cleavage and rearrangement occurred extensively on C- and B-rings of flavanol and generated various simpler aldehydes or acids. Besides, a number of dimers/trimers were produced. This contribution provides empirical proof of oxidative degradation of flavanols under strong alkaline condition. Meanwhile, detailed reaction mechanisms of C-/B-ring degradation and dimerization/polymerization phenomena are proposed to help understand the structural changes of flavanols under strong alkaline conditions.
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Abstract
Superoxide ion (O2(•-)) is of great significance as a radical species implicated in diverse chemical and biological systems. However, the chemistry knowledge of O2(•-) is rather scarce. In addition, numerous studies on O2(•-) were conducted within the latter half of the 20th century. Therefore, the current advancement in technology and instrumentation will certainly provide better insights into mechanisms and products of O2(•-) reactions and thus will result in new findings. This review emphasizes the state-of-the-art research on O2(•-) so as to enable researchers to venture into future research. It comprises the main characteristics of O2(•-) followed by generation methods. The reaction types of O2(•-) are reviewed, and its potential applications including the destruction of hazardous chemicals, synthesis of organic compounds, and many other applications are highlighted. The O2(•-) environmental chemistry is also discussed. The detection methods of O2(•-) are categorized and elaborated. Special attention is given to the feasibility of using ionic liquids as media for O2(•-), addressing the latest progress of generation and applications. The effect of electrodes on the O2(•-) electrochemical generation is reviewed. Finally, some remarks and future perspectives are concluded.
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Affiliation(s)
| | | | - Inas M AlNashef
- Department of Chemical and Environmental Engineering, Masdar Institute of Science and Technology , Abu Dhabi, United Arab Emirates
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Budanur BM, Khan FA. Superoxide chemistry revisited: synthesis of tetrachloro-substituted methylenenortricyclenes. Beilstein J Org Chem 2014; 10:2531-8. [PMID: 25383124 PMCID: PMC4222393 DOI: 10.3762/bjoc.10.264] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 10/21/2014] [Indexed: 11/26/2022] Open
Abstract
An unexpected reactivity of the superoxide ion leading to the synthesis of tetrachloroaryl/vinyl-substituted nortricyclenes through its dual mode of action has been reported. KO2 was found to be superior and the only reagent to perform this kind of reaction over other conventional bases. Addition of the antioxidant BHT (2,6-di-tert-butyl-4-methylphenol) improved the yields of methylenenortricyclenes. A complete deuterium incorporation was observed in the superoxide-mediated reaction in DMSO-d 6. Friedel-Crafts acylation reactions of 3-methylenenorticyclenes yielded 2-propanone-substituted pentachloronorbornenes.
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Affiliation(s)
- Basavaraj M Budanur
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India
| | - Faiz Ahmed Khan
- Department of Chemistry, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram-502205, India
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Kruk I, Michalska T, Kładna A, Berczyński P, Aboul-Enein HY. Chemiluminescence investigations of antioxidative activities of some antibiotics against superoxide anion radical. LUMINESCENCE 2011; 26:598-603. [DOI: 10.1002/bio.1278] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Accepted: 01/04/2011] [Indexed: 11/10/2022]
Affiliation(s)
- Irena Kruk
- Institute of Physics; Faculty of Mechanical Engineering and Mechatronics; West Pomeranian University of Technology in Szczecin; Poland
| | - Teresa Michalska
- Institute of Physics; Faculty of Mechanical Engineering and Mechatronics; West Pomeranian University of Technology in Szczecin; Poland
| | - Aleksandra Kładna
- Department of Medical History and Ethics; Pomeranian Medical University of Szczecin; Poland
| | - Paweł Berczyński
- Institute of Physics; Faculty of Mechanical Engineering and Mechatronics; West Pomeranian University of Technology in Szczecin; Poland
| | - Hassan Y. Aboul-Enein
- Pharmaceutical and Medicinal Chemistry Department; Pharmacetical and Drug Industries Research Division; National Research Centre; Dokki; Cairo; 12311; Egypt
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Salazar R, Navarrete-Encina PA, Squella JA, Camargo C, Núñez-Vergara LJ. Reactivity of C4-indolyl substituted 1,4-dihydropyridines toward superoxide anion (O2•) in dimethylsulfoxide. J PHYS ORG CHEM 2009. [DOI: 10.1002/poc.1453] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Funabiki T. Functional model oxygenations by nonheme iron complexes. ADVANCES IN CATALYTIC ACTIVATION OF DIOXYGEN BY METAL COMPLEXES 2003. [DOI: 10.1007/0-306-47816-1_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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9
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Variation in the chemistry of the TiO2-mediated degradation of hydroxy- and methoxybenzenes: electron transfer and HOads initiated chemistry. J Photochem Photobiol A Chem 2001. [DOI: 10.1016/s1010-6030(01)00472-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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D. H. Bugg T, J. Winfield C. Enzymatic cleavage of aromatic rings: mechanistic aspects of the catechol dioxygenases and later enzymes of bacterial oxidative cleavage pathways. Nat Prod Rep 1998. [DOI: 10.1039/a815513y] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Yoshioka Y, Yamanaka S, Yamada S, Kawakami T, Nishino M, Yamaguchi K, Nishinaga A. Theoretical and Experimental Studies of a Charge-Transfer Mechanism for Biomimetic Oxygenations of Phenol and Indol Derivatives. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1996. [DOI: 10.1246/bcsj.69.2701] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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13
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Jovanovic S, Kónya K, Scaiano J. Redox reactions of 3,5-di-tert-butyl-1,2-benzoquinone. Implications for reversal of paper yellowing. CAN J CHEM 1995. [DOI: 10.1139/v95-222] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One- and two-electron transfer reactions of 3,5-di-tert-butylcatechol and the corresponding quinone were studied by fast kinetic spectroscopy coupled with laser photolysis and pulse radiolysis, and by cyclic voltammetry in aqueous solutions. Photoionization of catechol yields the same semiquinone radical as the formate-radical-induced quinone reduction in the pulse radiolysis experiment. The neutral semiquinone radical deprotonates at pKr = 6.0 ± 0.1, as deduced from the pH induced changes in the radical spectra. The two-electron reduction potentials of quinone and catechol were measured by cyclic voltammetry in aqueous solutions containing 25% methanol in the pH range 3–14. The pH dependence has two linear parts with slopes of 0.056 and 0.03 V/pH, intersecting at pKa = 10.0. This is in excellent agreement with pKa = 10.05 ± 0.05 obtained spectrophotometrically. The reduction potential of 3,5-di-tert-butyl quinone, E7 = 0.01 ± 0.04 V, was obtained from the one-electron transfer equilibrium of the quinone with the oxygen/superoxide redox couple by pulse radiolysis. The rate constant of the reaction of quinone with the superoxide radical, k = 1.2 × 109 M−1 s−1, is higher than those of the superoxide reduction by catechols and phenols (typically ~ 105 M−1 s−1); thus, lignin o-quinones could be efficient scavengers of superoxide under the conditions relevant for the photo-induced yellowing of lignin-rich paper. The reaction with [Formula: see text] effectively bleaches yellow quinone and generates metastable furanone, which hydrolyses to muconic acid, thus completely eliminating yellow quinone. 3,5-Di-tert-butylquinone also undergoes rapid bleaching with ascorbate, k = 600 ± 100 M−1 s−1, in methanol. The reaction has a 1:1 stoichiometry and leads to complete reduction of quinone to catechol with concomitant oxidation of ascorbate to dehydroascorbate. This unusual selectivity and the fact that the reaction of the milder oxidant 3,5-di-tert-butylquinone is an order of magnitude faster than that of stronger oxidant p-benzoquinone (k = 60 ± 10 M−1 s−1) suggest that a nucleophilic attack of quinone at the ascorbate double bond initiates the reaction. Keywords: superoxide, lignin, photochemistry, quinone.
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Li W, Sotiriou-Leventis C, Saha M, Fu PP, Giese RW. Superoxide Oxidation of Hydroxy- and Keto-Polyaromatics Including Internal Quinones. SYNTHETIC COMMUN 1993. [DOI: 10.1080/00397919308020407] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Kumakura A, Kobayashi K, Uchida Y, Osawa Z. Reaction of polyacrylonitrile with superoxide anion. Polym Degrad Stab 1992. [DOI: 10.1016/0141-3910(92)90037-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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Mascagna D, Costantini C, d'Ischia M, Prota G. Tyrosinase-catalysed oxidation of the new melanocytotoxic agent N-4-hydroxyphenylglycine: Unusual cleavage of the 4-aminophenol ring to muconic semialdehyde derivatives. Tetrahedron 1992. [DOI: 10.1016/s0040-4020(01)80498-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Abdel-Baky S, Sotiriou-Leventis C, Giese RW. Superoxide oxidation of 1-nitropyrene-cis-dihydrodiols. Tetrahedron 1991. [DOI: 10.1016/s0040-4020(01)86519-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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18
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Ohkubo K, Ishida H, Sagawa T, Miyata K, Yoshinaga K. Ring-opening dioxygenatton of 3,5-Di-t-butylcatechol by FeCl2/monodentate ligand/bidentate ligand systems. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/0304-5102(90)85244-c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Speier G, Tyeklár Z. The reaction of alkali metal catecholates with dioxygen in aprotic solvents. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/0304-5102(90)85001-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Miyagi A, Nishiyama S, Tsuruya S, Masai M. Catalysis of CuII- and CoII-polyvinylpyridine complexes in the oxidation of 3,5-Di-t-butylcatechol. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0304-5102(89)80272-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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21
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Hae Kim Y, Soo Kim K, Kyu Lee H. Oxidation of benzylic methylene compounds to ketones with 2-nitrobenzene peroxysulfonyl radical formed from its chloride and superoxide. Tetrahedron Lett 1989. [DOI: 10.1016/s0040-4039(01)93893-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Ménassa PE, Mak MK, Langford CH. A study of the photodecomposition of different polychlorinated biphenyls by surface modified titanium (iv) oxide particles. ACTA ACUST UNITED AC 1988. [DOI: 10.1080/09593338809384638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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23
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Jensen F, Foote CS. Chemistry of singlet oxygen--48. Isolation and structure of the primary product of photooxygenation of 3,5-di-t-butyl catechol. Photochem Photobiol 1987; 46:325-30. [PMID: 3671512 DOI: 10.1111/j.1751-1097.1987.tb04776.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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24
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Chang HS, Yon GH, Kim YH. Facile Synthesis of 2-Substituted Aminobenzoxazole. One Pot Cyclodesulfurization ofN-(2-Hydroxyphenyl)-N′-phenylthioureas with Superoxide Radical Anion. CHEM LETT 1986. [DOI: 10.1246/cl.1986.1291] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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Electrocatalysis of O2 reduction on Au surfaces modified by underpotential Pb and Tl adsorbates in acetonitrile. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/0022-0728(86)87049-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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26
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Ozawa T, Hanaki A. Oxidation of polyvalent porphyrin, tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin by superoxide ion. Inorganica Chim Acta 1985. [DOI: 10.1016/s0020-1693(00)81612-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Chuaqui CA, Delaney S, Merritt J. Reactions of 2-phenyl-4,4-dimethyl-2-oxazolin-5-one and 2-phenyl-4-ethyl-2-oxazolin-5-one with KO2 in aprotic solvents (Issued as AECL No. 7964). Tetrahedron 1983. [DOI: 10.1016/s0040-4020(01)92156-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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30
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Futamura S, Yamazaki K, Ohta H, Kamiya Y. Photoinduced Electron Transfer Oxidation. I. 9,10-Dicyanoanthracene-sensitized Photooxidation of Hindered Phenols. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1982. [DOI: 10.1246/bcsj.55.3852] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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31
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32
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Weiner LM, Gritzan NP, Bazhin NM, Lyakhovich VV. Microsomal and photochemical oxidation and reduction of 1-piperidinoanthraquinone. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 714:234-42. [PMID: 6799005 DOI: 10.1016/0304-4165(82)90329-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In microsomes of control Wistar rats, NADPH-dependent reduction of 1-piperidinoanthraquinone (1-PA) to the corresponding hydroquinone, in the absence of oxygen, has been observed. Two facts ((i) inhibition of the formation of 1-piperidinoanthrahydroquinone (1-PAH) by metyrapone and antibodies to cytochrome P-450, and (ii) increase in the rate of 1-PAH formation upon induction of rats by phenobarbital) indicate that cytochrome P-450 participates in the reduction of 1-PA. Since 1-PA is a substrate of cytochrome P-450 and is oxidized in microsomes to (N-anthraquinonyl-1)-delta-aminovaleric acid (AAV), model experiments have been conducted to examine whether the reduced forms of 1-PA are involved in its oxidation. During photochemical generation of 1-PAH and its subsequent oxidation (N-anthraquinonyl-1)-delta-aminovaleric aldehyde (AAVal) is formed. However, this product is formed without participation of activated form of the substrate and oxygen. AAVal is a substrate in photochemical systems, apparently, is a precursor of AAV in microsomal oxidation of 1-PA. AAVal is substrate of cytochrome P-450 (the Type 1 of binding) and is oxidized quantitatively in microsomal systems to yield AAV. The date obtained enable us to propose a possible mechanism of enzyme oxidation of 1-PA.
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Dureja P, Casida JE, Ruzo LO. Superoxide-mediated dehydrohalogenation reactions of the pyrethroid permethrin and other chlorinated pesticides. Tetrahedron Lett 1982. [DOI: 10.1016/s0040-4039(00)85557-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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34
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Sawaki Y, Ogata Y. Mechanism of the Reaction of Nitriles with Alkaline Hydrogen Peroxide. Reactivity of Peroxycarboximidic Acid and Application to Superoxide Ion Reaction. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1981. [DOI: 10.1246/bcsj.54.793] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Sakamoto H, Funabiki T, Yoshida S, Tarama K. Oxidation of 3,5-Di-t-butylcatechol Catalyzed by Metal Acetylacetonates in Organic Solvents. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1979. [DOI: 10.1246/bcsj.52.2760] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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37
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Chemiluminescence in alkaline solutions of hydrogen peroxide and o-phenanthroline. Russ Chem Bull 1979. [DOI: 10.1007/bf00923562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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38
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Afanas'ev IB, Polozova NI. Interaction of the oxygen anion radical
$$O_{\dot 2}^ - $$
with vitamins and hormones having hydroquinone and quinone structures. Pharm Chem J 1979. [DOI: 10.1007/bf00781043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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39
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Piatt J, O'Brien PJ. Singlet oxygen formation by a peroxidase, H2O2 and halide system. EUROPEAN JOURNAL OF BIOCHEMISTRY 1979; 93:323-32. [PMID: 428384 DOI: 10.1111/j.1432-1033.1979.tb12826.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Evidence for singlet oxygen formation has been obtained for the lactoperoxidase, H2O2 and bromide system by monitoring 2,3-diphenylfuran and diphenylisobenzofuran oxidation, O2 evolution, and chemiluminescence. This could provide an explanation for the cytotoxic and microbicidal activity of peroxidases and polymorphonuclear leukocytes. Evidence for singlet oxygen formation included the following. (a) Chemiluminescence accompanying the enzymic reaction was doubled in a deuterated buffer and inhibited by singlet oxygen traps. (b) The singlet oxygen traps, diphenylfuran and diphenylisobenzofuran, were oxidized to their known singlet oxygen oxidation products in the presence of lactoperoxidase, hydrogen peroxide and bromide. (c) The rate of oxidation of diphenylfuran and diphenylisobenzofuran was inhibited when monitored in the presence of known singlet oxygen traps or quenchers. (d) Oxygen evolution from the enzymic reaction was inhibited by singlet oxygen traps but not by singlet oxygen quenchers. (e) The traps or quenchers which were effective inhibitors in the experiments above did not inhibit peroxidase activity, were not competitive peroxidase substrates and did not react with the hypobromite intermediate since they did not inhibit hydrogen peroxide consumption by the enzyme. Using these criteria, various biological molecules were tested for their reactivity with singlet oxygen. Furthermore, by studying their effect on oxygen release by the enzymic reaction, it could be ascertained whether they were acting as singlet oxygen traps or quenchers.
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Nishinaga A, Itahara T, Shimizu T, Tomita H, Nishizawa K, Matsuura T. THE ROLE OF DIOXYGEN SPECIES IN THE BASE- AND COBALT-CATALYZED OXYGENATION OF HINDERED PHENOLS. Photochem Photobiol 1978. [DOI: 10.1111/j.1751-1097.1978.tb06999.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Tsuji J, Takayanagi H. Oxidative cleavage reactions of catechol and phenol to monoester of cis,cis,-muconic acid with the oxidizing systems of O2/CuCl, KOH/CuCl2. Tetrahedron 1978. [DOI: 10.1016/0040-4020(78)88097-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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45
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46
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Danen WC, Warner R. The remarkable nucleophilicity of superoxide anion radical. rate constants for reaction of superoxide ion with aliphatic bromides. Tetrahedron Lett 1977. [DOI: 10.1016/s0040-4039(01)92810-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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47
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Matsumoto S, Matsuo M. The reaction of a α-tocopherol model compound with KO2, a new oxidation product of 6-hydroxy-2,2,5,7,8-pentamethylchroman. Tetrahedron Lett 1977. [DOI: 10.1016/s0040-4039(01)83663-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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48
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50
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Moro-Oka Y, Chung PJ, Arakawa H, Ikawa T. CHEMISTRY OF SUPEROXIDE ION. REACTION OF SUPEROXIDE ION WITH SUBSTRATES HAVING LABILE HYDROGENS. CHEM LETT 1976. [DOI: 10.1246/cl.1976.1293] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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