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Skotnicki K, Janik I, Sadowska K, Leszczynska G, Bobrowski K. Radiation-Induced Oxidation Reactions of 2-Selenouracil in Aqueous Solutions: Comparison with Sulfur Analog of Uracil. Molecules 2021; 27:molecules27010133. [PMID: 35011366 PMCID: PMC8746332 DOI: 10.3390/molecules27010133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 11/29/2022] Open
Abstract
One-electron oxidation of 2-selenouracil (2-SeU) by hydroxyl (●OH) and azide (●N3) radicals leads to various primary reactive intermediates. Their optical absorption spectra and kinetic characteristics were studied by pulse radiolysis with UV-vis spectrophotometric and conductivity detection and by the density functional theory (DFT) method. The transient absorption spectra recorded in the reactions of ●OH with 2-SeU are dominated by an absorption band with an λmax = 440 nm, the intensity of which depends on the concentration of 2-SeU and pH. Based on the combination of conductometric and DFT studies, the transient absorption band observed both at low and high concentrations of 2-SeU was assigned to the dimeric 2c-3e Se-Se-bonded radical in neutral form (2●). The dimeric radical (2●) is formed in the reaction of a selenyl-type radical (6●) with 2-SeU, and both radicals are in equilibrium with Keq = 1.3 × 104 M−1 at pH 4 (below the pKa of 2-SeU). Similar equilibrium with Keq = 4.4 × 103 M−1 was determined for pH 10 (above the pKa of 2-SeU), which admittedly involves the same radical (6●) but with a dimeric 2c-3e Se-Se bonded radical in anionic form (2●−). In turn, at the lowest concentration of 2-SeU (0.05 mM) and pH 10, the transient absorption spectrum is dominated by an absorption band with an λmax = 390 nm, which was assigned to the ●OH adduct to the double bond at C5 carbon atom (3●) based on DFT calculations. Similar spectral and kinetic features were also observed during the ●N3-induced oxidation of 2-SeU. In principle, our results mostly revealed similarities in one-electron oxidation pathways of 2-SeU and 2-thiouracil (2-TU). The major difference concerns the stability of dimeric radicals with a 2c-3e chalcogen-chalcogen bond in favor of 2-SeU.
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Affiliation(s)
- Konrad Skotnicki
- Centre of Radiation Research and Technology, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
- Correspondence: (K.S.); (I.J.); Tel.: +48-22-504-1292 (K.S.)
| | - Ireneusz Janik
- Notre Dame Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA
- Correspondence: (K.S.); (I.J.); Tel.: +48-22-504-1292 (K.S.)
| | - Klaudia Sadowska
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, 90-924 Lodz, Poland; (K.S.); (G.L.)
| | - Grazyna Leszczynska
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, 90-924 Lodz, Poland; (K.S.); (G.L.)
| | - Krzysztof Bobrowski
- Centre of Radiation Research and Technology, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
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2
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Singh BG, Kunwar A. Redox reactions of organoselenium compounds: Implication in their biological activity. Free Radic Res 2021; 55:641-654. [PMID: 33555213 DOI: 10.1080/10715762.2021.1882678] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Antioxidant activity of organoselenium compounds belonging to different classes i.e. functionalized aliphatic, aromatic and cyclic selenoethers, are compared on the basis of their ability to scavenge reactive oxygen species like hydroxyl and peroxyl radicals and to exhibit glutathione peroxidase (GPx) like catalytic activity. The comparative analysis has revealed that the antioxidant activity of the organoselenium compounds show direct correlation with the energy of the highest occupied molecular orbital (HOMO) and neighboring group participation that stabilizes the reaction intermediate. Finally, structural features responsible for improving the rate of reaction of organoselenium compounds with free radical/molecular oxidants have been discussed on the basis of the compounds screened at our institute.
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Affiliation(s)
- Beena G Singh
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Mumbai, India
| | - Amit Kunwar
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, India.,Homi Bhabha National Institute, Mumbai, India
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3
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Dhayagude AC, Debnath AK, Joshi SS, Kapoor S, Maiti N. Adsorption of
l
‐selenomethionine and
l
‐selenocystine on the surface of silver nanoparticles: A spectroscopic study. NANO SELECT 2020. [DOI: 10.1002/nano.202000061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Akshay C. Dhayagude
- Radiation and Photochemistry Division Bhabha Atomic Research Center Mumbai 400085 India
- Department of Chemistry Savitribai Phule Pune University Pune 411007 India
- K. K. Wagh College, (Present address), Pimpalgaon (B) Nashik 422209 India
| | - Anil K. Debnath
- Technical Physics Division Bhabha Atomic Research Centre Mumbai 400085 India
- Homi Bhabha National Institute Mumbai 400094 India
| | - Satyawati S. Joshi
- Department of Chemistry Savitribai Phule Pune University Pune 411007 India
| | - Sudhir Kapoor
- Radiation and Photochemistry Division Bhabha Atomic Research Center Mumbai 400085 India
| | - Nandita Maiti
- Radiation and Photochemistry Division Bhabha Atomic Research Center Mumbai 400085 India
- Homi Bhabha National Institute Mumbai 400094 India
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4
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Shinde RG, Khan AA, Barik A. Formation of two centre three electron bond by hydroxyl radical induced reaction of thiocoumarin: evidence from experimental and theoretical studies. Free Radic Res 2019; 53:629-640. [PMID: 31072168 DOI: 10.1080/10715762.2019.1617417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Radiation chemical studies of thioesculetin (1), a thioketone derivative of coumarin, were performed by both pulse radiolysis technique and DFT calculations. Hydroxyl (•OH) radical reaction with 1 resulted transients absorbing at 320, 360 and 500 nm. To identify the nature of the transients, the reaction was studied with specific one-electron oxidant (N3•) radical, where 360 nm band was absent. The transient absorption at 500 nm was concentration-dependent. The overall impression for •OH radical reaction was that the transient absorbing at 320, 360 and 500 nm was due to sulphur centred monomer radical, hydroxysulfuranyl and dimer radical of 1 respectively. The equilibrium constant between the monomer to dimer radical was 3.75 × 104 M-1. From the transients' redox nature, it was observed that 57 and 24% of •OH radical yielded to oxidising and reducing products respectively. Further, the product analysis by HPLC suggested that the dimer radical disproportionate to esculetin and thioesculetin. DFT energy calculation for all the possible transients revealed that dimer radical has the lowest energy. The HOMO of 1 and its monomer radical suggested that the electron density was localised on the sulphur atom. The bond length between the two sulphur atoms in dimer radical was 2.88 Å which was less than the van der Waals distance. Bond order between the two sulphur atoms was 0.55, suggesting that the bond was two centre three electron (2c-3e). From TD-DFT calculation, the electronic transition of dimer radical was at 479 nm which was in close agreement with the experimental value. The nature of the electronic transition was σ → σ* from a 2c - 3e bond.
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Affiliation(s)
- Rupali G Shinde
- a Department of Chemistry , Savitribai Phule Pune University , Pune , India.,b Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Mumbai , India
| | - Ayesha A Khan
- a Department of Chemistry , Savitribai Phule Pune University , Pune , India
| | - Atanu Barik
- b Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Mumbai , India
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5
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Singh BG, Kumar P, Phadnis P, Iwaoka M, Priyadarsini KI. Free radical induced selenoxide formation in isomeric organoselenium compounds: the effect of chemical structures on antioxidant activity. NEW J CHEM 2019. [DOI: 10.1039/c9nj02227a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Formation of selenoxides improves the antioxidant activity of organoselenium compounds and should be considered as an important marker in the design of new selenium based antioxidants.
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Affiliation(s)
- Beena G. Singh
- Radiation & Photochemistry Division
- Bhabha Atomic Research Centre
- Trombay
- Mumbai-400085
- India
| | - Pavitra Kumar
- Radiation & Photochemistry Division
- Bhabha Atomic Research Centre
- Trombay
- Mumbai-400085
- India
| | - P. Phadnis
- Chemistry Division
- Bhabha Atomic Research Centre
- Trombay
- Mumbai-400085
- India
| | - Michio Iwaoka
- Department of Chemistry
- School of Science
- Tokai University
- Kitakaname
- Hiratsuka-shi
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6
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Liu C, Xu L, Tian H, Yao H, Elding LI, Shi T. Kinetics and mechanism for reduction of Pt(IV) anticancer model compounds by Se-methyl L-selenocysteine. Comparison with L-selenomethionine. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.09.056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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7
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Bouchet LM, Argüello JE. Photoinduced One-Electron Oxidation of Aromatic Selenides: Effect of the Structure on the Reversible Dimerization Reaction. J Org Chem 2018; 83:5674-5680. [PMID: 29683656 DOI: 10.1021/acs.joc.8b00684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photochemical one-electron oxidation of alkyl aryl selenides was studied by means of laser flash photolysis (355 nm). Quenching of the sensitizers in their excited state leads to selenide radical cation in the presence of selenium derivatives. The π-type dimer of methyl phenyl selenide radical cation was detected at 630 nm at expenses of the monomeric radical cation (530 nm). The effect of modification of the aryl and alkyl substituents was also studied, resulting that the formation of dimers depends on both, the electronic properties and steric hindrance of the substituents. Both effects, an increase in steric hindrance in the alkyl moiety or the presence of strongly electron donor groups in the aromatic substituent that stabilizes the radical cation, prevent the dimer formation.
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Affiliation(s)
- Lydia M Bouchet
- INFIQC-CONICET-UNC, Dpto. de Química Orgánica, Facultad de Ciencias Químicas , Universidad Nacional de Córdoba, Ciudad Universitaria , X5000HUA Córdoba , Argentina
| | - Juan E Argüello
- INFIQC-CONICET-UNC, Dpto. de Química Orgánica, Facultad de Ciencias Químicas , Universidad Nacional de Córdoba, Ciudad Universitaria , X5000HUA Córdoba , Argentina
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8
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Priyadarsini KI, Singh BG. Selenium Centered Radicals: How Do They Differ from Sulfur Centered Radicals? PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES INDIA SECTION A-PHYSICAL SCIENCES 2016. [DOI: 10.1007/s40010-016-0308-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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9
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Huo S, Dong J, Shen S, Ren Y, Song C, Xu J, Shi T. L-selenomethionine reduces platinum(IV) anticancer model compounds at strikingly faster rates than L-methionine. Dalton Trans 2015; 43:15328-36. [PMID: 25075569 DOI: 10.1039/c4dt01528b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
L-Selenomethionine (SeMet), the predominant form of selenium acquired from the diet by humans, has been used as a supplement, and exhibit some important functions like cancer prevention and antioxidative defense. Its interactions with Pt(II) anticancer drugs have been characterized, but its redox reactions with platinum(IV) anticancer prodrugs have not been exploited. In this work, the oxidation of SeMet by Pt(IV) anticancer model compounds trans-[PtX2(CN)4](2-) (X = Cl, Br) was characterized. A stopped-flow spectrometer was used to record the rapid scan spectra and to follow the reaction kinetics over a wide pH range. An overall second-order rate law was derived: -d[Pt(IV)]/dt = k'[Pt(IV)][SeMet], where k' pertains to the observed second-order rate constants. The k'-pH profiles showed that k' increased only about 6 times even though the solution pH was varied from 0.25 to 10.5. The redox stoichiometry was determined as Δ[Pt(IV)]/Δ[SeMet] = 1 : (1.07 ± 0.07), suggesting that SeMet was oxidized to selenomethionine selenoxide. The selenoxide together with its hydrated form was identified explicitly by high resolution mass spectral analysis. A reaction mechanism was proposed which encompassed three parallel rate-determining steps relying on the protolytic species of SeMet. Rate constants of the rate-determining steps were obtained from the simulations of the k'-pH profiles. Activation parameters were determined for the reactions of the zwitterionic form of SeMet with the Pt(IV) complexes. A bridged electron transfer process is delineated in the rate-determining steps and several lines of evidence support the bridged electron transfer mode. Strikingly, reduction of [PtX2(CN)4](2-) by SeMet is 3.7 × 10(3)-5.7 × 10(4) times faster than that by L-methionine. Some potential biological consequences resulting from the strikingly fast reduction are discussed.
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Affiliation(s)
- Shuying Huo
- College of Chemistry and Environmental Science, and the MOE Key Laboratory of Medicinal Chemistry and Molecular Diagnostics, Hebei University, Baoding 071002, Hebei Province, P. R. China.
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10
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Carroll L, Davies MJ, Pattison DI. Reaction of low-molecular-mass organoselenium compounds (and their sulphur analogues) with inflammation-associated oxidants. Free Radic Res 2015; 49:750-67. [PMID: 25854915 DOI: 10.3109/10715762.2015.1018247] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Selenium is an essential trace element in mammals, with the majority specifically encoded as seleno-L-cysteine into a range of selenoproteins. Many of these proteins play a key role in modulating oxidative stress, via either direct detoxification of biological oxidants, or repair of oxidised residues. Both selenium- and sulphur-containing residues react readily with the wide range of oxidants (including hydrogen peroxide, radicals, singlet oxygen and hypochlorous, hypobromous, hypothiocyanous and peroxynitrous acids) that are produced during inflammation and have been implicated in the development of a range of inflammatory diseases. Whilst selenium has similar properties to sulphur, it typically exhibits greater reactivity with most oxidants, and there are considerable differences in the subsequent reactivity and ease of repair of the oxidised species that are formed. This review discusses the chemistry of low-molecular-mass organoselenium compounds (e.g. selenoethers, diselenides and selenols) with inflammatory oxidants, with a particular focus on the reaction kinetics and product studies, with the differences in reactivity between selenium and sulphur analogues described in the selected examples. These data provide insight into the therapeutic potential of low-molecular-mass selenium-containing compounds to modulate the activity of both radical and molecular oxidants and provide protection against inflammation-induced damage. Progress in their therapeutic development (including modulation of potential selenium toxicity by strategic design) is demonstrated by a brief summary of some recent studies where novel organoselenium compounds have been used as wound healing or radioprotection agents and in the prevention of cardiovascular disease.
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Affiliation(s)
- L Carroll
- The Heart Research Institute , Newtown, Sydney , Australia
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11
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Singh BG, Nadkarni SA, Jain VK, Priyadarsini KI. Effect of alkyl chain length on one-electron oxidation of bis(alkyl carboxylic acid) selenides: implication on their antioxidant ability. RSC Adv 2015. [DOI: 10.1039/c5ra10355j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Formation of a stable five membered transient in seleno bis(propanoic acid) reduces its radiolytic degradation and enhances its peroxyl radical scavenging activity.
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Affiliation(s)
- B. G. Singh
- Radiation & Photochemistry Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - S. A. Nadkarni
- Radiation & Photochemistry Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - V. K. Jain
- Chemistry Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
| | - K. I. Priyadarsini
- Radiation & Photochemistry Division
- Bhabha Atomic Research Centre
- Mumbai-400 085
- India
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12
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Barik A, Singh BG, Sharma A, Jain VK, Priyadarsini KI. Pulse Radiolysis Studies of 3,5-Dimethyl Pyrazole Derivatives of Selenoethers. J Phys Chem A 2014; 118:10179-87. [DOI: 10.1021/jp507369q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Atanu Barik
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Beena G. Singh
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Asmita Sharma
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Vimal K. Jain
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - K. Indira Priyadarsini
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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13
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Singh BG, Thomas E, Sawant SN, Takahashi K, Dedachi K, Iwaoka M, Priyadarsini KI. Radical Cations of Aromatic Selenium Compounds: Role of Se···X Nonbonding Interactions. J Phys Chem A 2013; 117:9259-65. [DOI: 10.1021/jp405798h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Kohei Takahashi
- Department
of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan
| | - Kenchi Dedachi
- Department
of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan
| | - Michio Iwaoka
- Department
of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan
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14
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Prasanthkumar KP, Suresh CH, Aravindakumar CT. Dimer radical cation of 4-thiouracil: a pulse radiolysis and theoretical study. J PHYS ORG CHEM 2013. [DOI: 10.1002/poc.3116] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- K. P. Prasanthkumar
- School of Chemical Sciences; Mahatma Gandhi University; Kottayam 686560 Kerala India
| | - Cherumuttathu H. Suresh
- National Institute for Interdisciplinary Science & Technology; Trivandrum 695019 Kerala India
| | - C. T. Aravindakumar
- School of Environmental Sciences; Mahatma Gandhi University; Kottayam 686560 Kerala India
- Inter University Instrumentation Center; Mahatma Gandhi University; Kottayam 686560 Kerala India
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15
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Prasanthkumar KP, Suresh CH, Aravindakumar CT. Oxidation reactions of 2-thiouracil: a theoretical and pulse radiolysis study. J Phys Chem A 2012; 116:10712-20. [PMID: 23061532 DOI: 10.1021/jp303808r] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction of hydroxyl radical ((•)OH) with the nucleic acid base analogue 2-thiouracil (1) has been studied by pulse radiolysis experiments and DFT. The generic intermediate radicals feasible for the (•)OH reactions with 1, namely, one electron oxidation product (1(•+)), (•)OH-adducts (3(•), 4(•), and 5(•)), and H-abstracted radicals (6(•) and 7(•)), were characterized by interpreting their electronic and structural properties along with calculated energetics and UV-vis spectra. Pulse radiolysis experiments showed that the transient formed in the reaction of (•)OH with 1 in water at pH 6.5 has λ(max) at 430 nm. A bimolecular rate constant, k(2) of 9.6 × 10(9) M(-1) s(-1), is determined for this reaction via competition kinetics with 2-propanol. The experiments suggested that the transient species could be a dimer radical cation 2(•+), formed by the reaction of 1 with the radical cation 1(•+). For this reaction, an equilibrium constant of 4.7 × 10(3) M(-1) was determined. The transient formed in the reaction of 1 with pulse radiolytically produced Br(2)(•-) at pH 6.5 as well as Cl(2)(•-) at pH 1 has also produced λ(max) at 430 nm and suggested the formation of 2(•+). The calculated UV-vis spectra of the transient species (1(•+), 3(•), 4(•), 5(•), 6(•), and 7(•)) showed no resemblance to the experimental spectra, while that of 2(•+) (λ(max) = 420 nm) agreed well with the experimental value and thus confirmed the formation of 2(•+). The 420 nm peak was due to σ → σ* electronic excitation centered on a 2-center-3-electron (2c-3e) sulfur-sulfur bond [-S∴S-]. 2(•+) is the first reported example of a dimer radical cation in a pyrimidine heterocyclic system. Further, 5-C and 6-C substituted (substituents are -F, -Cl, -NH(2), -N(CH(3))(2), -OCH(3), -CF(3), -CH(3), -CH(2)CH(3), n-propyl, phenyl, and benzyl) and 5,6-disubstituted 2-thiouracil systems have been characterized by DFT and found that the reaction (1 + 1(•+) → 2(•+)) is exergonic (1.12-13.63 kcal/mol) for many of them.
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Affiliation(s)
- K P Prasanthkumar
- School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560, India
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16
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Singh BG, Thomas E, Kumakura F, Dedachi K, Iwaoka M, Priyadarsini KI. One-electron redox processes in a cyclic selenide and a selenoxide: a pulse radiolysis study. J Phys Chem A 2010; 114:8271-7. [PMID: 20666479 DOI: 10.1021/jp103727e] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
One-electron redox reactions of cyclic selenium compounds, DL-trans-3,4-dihydroxy-1-selenolane (DHS(red)), and DL-trans-3,4-dihydroxy-1-selenolane oxide (DHS(ox)) were carried out in aqueous solutions using nanosecond pulse radiolysis, and the resultant transients were detected by absorption spectroscopy. Both *OH radical and specific one-electron oxidant, Br(2)(*-) radical reacted with DHS(red) to form similar transients absorbing at 480 nm, which has been identified as a dimer radical cation (DHS(red))(2)(*+). Secondary electron transfer reactions of the (DHS(red))(2)(*+) were studied with 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS(2-)) and superoxide (O(2)(*-)) radicals. The bimolecular rate constants for the electron transfer reaction between (DHS(red))(2)(*+) with ABTS(2-) was determined as 2.4 +/- 0.4 x 10(9) M(-1) s(-1). From this reaction, the yield of (DHS(red))(2)(*+) formed on reaction with *OH radical was estimated in the presence of varying phosphate concentrations. (DHS(red))(2)(*+) reacted with O(2)(*-) radical with a bimolecular rate constant of 2.7 +/- 0.1 x 10(9) M(-1) s(-1) at pH 7. From the same reaction, the positive charge on (DHS(red))(2)(*+) was confirmed by the kinetic salt effect. HPLC analysis of the products formed in the reaction of (DHS(red))(2)(*+) with O(2)(*-) radicals showed formation of the selenoxide, DHS(ox). In order to know if a similar mechanism operated during the reduction of DHS(ox), its reactions with e(aq)(-) were studied at pH 7. The rate constant for this reaction was determined as 5.6 +/- 0.9 x 10(9) M(-1) s(-1), and no transient absorption could be observed in the wavelength region from 280 to 700 nm. It is proposed that the radical anion (DHS(ox))(*-) formed by a one-electron reduction would get protonated to form a hydroxyl radical adduct, which in presence of proton donors, would undergo dehydration to form DHS(*+). Evidence for this mechanism was obtained by converting DHS(*+) to (DHS(red))(2)(*+) with the addition of DHS(red) to the same system. Quantum chemical calculations provided supporting evidence for some of the redox reactions.
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Affiliation(s)
- Beena G Singh
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, India.
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17
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Tobien T, Bonifačić M, Naumov S, Asmus KD. Time-resolved study on the reactions of organic selenides with hydroxyl and oxide radicals, hydrated electrons, and H-atoms in aqueous solution, and DFT calculations of transients in comparison with sulfur analogues. Phys Chem Chem Phys 2010; 12:6750-8. [DOI: 10.1039/b923797f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Kumar BS, Kunwar A, Ahmad A, Kumbhare LB, Jain VK, Priyadarsini KI. In vitro radioprotection studies of organoselenium compounds: differences between mono- and diselenides. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2009; 48:379-384. [PMID: 19756688 DOI: 10.1007/s00411-009-0240-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 08/20/2009] [Indexed: 05/28/2023]
Abstract
Organoselenium compounds belonging to the class of monoselenides, such as selenomethionine (SeM) and methylselenocysteine (MSeCys) and diselenides including selenocystine (SeCys) and selenopropionic acid (SePA), were examined for their comparative radioprotective effects using in vitro models. Effects of these compounds on the inhibition of gamma-radiation induced lipid peroxidation in liposomes, protein carbonylation in bovine serum albumin (BSA) and strand breaks in pBR322 plasmid DNA, assessed, respectively, by the formation of thiobarbituric acid reactive substances, formation of 2,2'-dinitrophenyl hydrazine (DNPH) carbonyl complex and horizontal gel electrophoresis, were used to compare their radioprotective ability. The IC 50 values for SeCys, SePA, SeM and MSeCys for lipid peroxidation were 27 +/- 1, 33 +/- 2, 200 +/- 8 and 163 +/- 4 microM, respectively, and the values for inhibition of protein carbonylation were >200, 300 +/- 6, 464 +/- 8 and 436 +/- 3 microM, respectively. Inhibition of DNA strand break formation was tested at 200 microM for all the compounds and SePA and SeCys exhibited a protective effect on DNA, while SeM and MSeCys did not lead to any protection. The in vitro cytotoxicity studies in normal and tumor cells revealed that MSeCys and SeM were not cytotoxic to lymphocytes and EL4 tumor cells at the concentrations employed. In contrast, SeCys was toxic, with a higher effect on tumor cells than lymphocytes. Our studies suggest that the non-toxic diselenides like SePA should be explored as protective agents against gamma-irradiation induced damage.
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Affiliation(s)
- B Santhosh Kumar
- Department of Physiology, Deccan College of Medical Sciences, Hyderabad, India.
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Mishra B, Sharma A, Naumov S, Priyadarsini KI. Novel reactions of one-electron oxidized radicals of selenomethionine in comparison with methionine. J Phys Chem B 2009; 113:7709-15. [PMID: 19408939 DOI: 10.1021/jp900322z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pulse radiolysis studies on hydroxyl (*OH) radical reactions of selenomethionine (SeM), a selenium analogue of methionine, were carried out, and the resultant transient radical cations and their subsequent reactions have been reported. At pH<3, the >Se*-OH radical adducts produced on reaction of SeM with *OH radical were converted to selenium centered radical cations (Se*+M), which react with another molecule of SeM to form dimer radical cation M(Se therefore Se)M+. At pH 7, the >Se*-OH radical adducts were converted to a monomer radical of the type (Se therefore N)M+ that acquires intramolecular stability through interaction with the lone pair of the N atom and this radical is denoted as SeM*+. SeM*+ decayed by first order kinetics, and the reduction potential of the couple SeM*+/SeM was determined to be 1.21+/-0.05 V vs NHE at pH 7. SeM*+ oxidized ABTS2- and TMPD with rate constants of (2.5+/-0.1)x10(8) and (6.1+/-0.2)x10(8) M(-1) s(-1), respectively, and reacted with hydroxide ion with a rate constant of (3.8+/-0.9)x10(5) M(-1) s(-1). SeM*+ reacts with molecular oxygen, and the rate constant for this reaction was determined to be (4.3+/-0.2)x10(8) M(-1) s(-1); similar reaction with methionine could not be observed experimentally. Like methionine radical cations, SeM*+ undergoes decarboxylation, although with lesser yield, to produce reducing 3-methyl-selenopropyl amino radicals (referred as alpha-amino radicals). The formation of these radicals was confirmed both by the estimation of the liberated CO2 and by one-electron reduction of MV2+, thionine, and PNAP. These results have been supported by quantum chemical calculations. Implications of these results in the biological role of SeM have also been briefly discussed.
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Affiliation(s)
- B Mishra
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India
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Naumov S, Bonifačić M, Glass RS, Asmus KD. Theoretical calculations and experimental data on spectral, kinetic and thermodynamic properties of Se∴N and S∴N three-electron-bonded, structurally stabilized σ2σ* radicals. RESEARCH ON CHEMICAL INTERMEDIATES 2009. [DOI: 10.1007/s11164-009-0045-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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AOYAMA C, TSUNODA M, FUNATSU T. Determination of Selenomethionine by High-Performance Liquid Chromatography-Fluorescence Detection Coupled with On-line Oxidation. ANAL SCI 2009; 25:63-5. [DOI: 10.2116/analsci.25.63] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Chiaki AOYAMA
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | - Makoto TSUNODA
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | - Takashi FUNATSU
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
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Mishra B, Barik A, Kunwar A, Kumbhare LB, Priyadarsini KI, Jain VK. Correlating the GPx Activity of Selenocystine Derivatives with One-Electron Redox Reactions. PHOSPHORUS SULFUR 2008. [DOI: 10.1080/10426500801901046] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Beena Mishra
- a Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Trombay, Mumbai, India
| | - Atanu Barik
- a Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Trombay, Mumbai, India
| | - Amit Kunwar
- a Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Trombay, Mumbai, India
| | - Liladhar B. Kumbhare
- a Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Trombay, Mumbai, India
| | - K. Indira Priyadarsini
- a Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Trombay, Mumbai, India
| | - Vimal K. Jain
- b Chemistry Division , Bhabha Atomic Research Centre , Trombay, Mumbai, India
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Priyadarsini KI, Mishra B. Radical cations of some water-soluble organoselenium compounds: Insights from pulse radiolysis studies. Radiat Phys Chem Oxf Engl 1993 2008. [DOI: 10.1016/j.radphyschem.2008.05.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Mishra B, Kumbhare LB, Jain VK, Priyadarsini KI. Pulse Radiolysis Studies on Reactions of Hydroxyl Radicals with Selenocystine Derivatives. J Phys Chem B 2008; 112:4441-6. [DOI: 10.1021/jp709880b] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mishra B, Kumar BS, Priyadarsini K. Pulse and γ-radiolysis studies on aqueous solution of 1,1′-dimethyl-2-selenourea. Radiat Phys Chem Oxf Engl 1993 2008. [DOI: 10.1016/j.radphyschem.2007.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Kunwar A, Mishra B, Barik A, Kumbhare LB, Pandey R, Jain VK, Priyadarsini KI. 3,3′-Diselenodipropionic Acid, an Efficient Peroxyl Radical Scavenger and a GPx Mimic, Protects Erythrocytes (RBCs) from AAPH-Induced Hemolysis. Chem Res Toxicol 2007; 20:1482-7. [PMID: 17900173 DOI: 10.1021/tx700137a] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
3,3'-diselenodipropionic acid (DSePA), a derivative of selenocystine, has been synthesized and examined for antioxidant activity, glutathione peroxidase (GPx) activity, and cytotoxicity. The effect of DSePA on membrane lipid peroxidation, release of hemoglobin, and intracellular K+ ion as a consequence of erythrocyte (red blood cells or RBCs) oxidation by free radicals generated by 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH) were used to evaluate the antioxidant ability. Lipid peroxidation, hemolysis, and K+ ion loss in RBCs were assessed, respectively, by formation of thiobarbituric acid reactive substances (TBARS), absorbance of hemoglobin at 532 nm and flame photometry. The IC50 values for lipid peroxidation, hemolysis, and K+ ion leakage were 45+/-5, 20+/-2, and 75+/-8 microM, respectively. DSePA treatment prevented the depletion of glutathione (GSH) levels in RBCs from free-radical-induced stress. DSePA is a good peroxyl radical scavenger and the bimolecular rate constant for the reaction of DSePA with a model peroxyl radical, trichloromethyl peroxyl radical (CCl 3O2*), was determined to be 2.7x10(8) M(-1) s(-1) using a pulse radiolysis technique. DSePA shows GPx activity with higher substrate specificity towards peroxides than thiols. The cytotoxicity of DSePA was studied in lymphocytes and EL4 tumor cells and the results showed that DSePA is nontoxic to these cells at the concentrations employed. These results when compared with two well-known selenium compounds, sodium selenite and ebselen, indicated that DSePA, although it shows lesser GPx activity, has higher free radical scavenging ability and lesser toxicity.
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Affiliation(s)
- Amit Kunwar
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India
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Adsorption of seleno-l-cystine on silver electrode surfaces investigated by surface-enhanced Raman scattering. J Electroanal Chem (Lausanne) 2007. [DOI: 10.1016/j.jelechem.2007.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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