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Kazemi SY, Abedirad SM. Effect of glutathione on peroxyoxalate chemiluminescence of hypericin as the fluorophore. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 118:782-786. [PMID: 24152863 DOI: 10.1016/j.saa.2013.07.081] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 07/03/2013] [Accepted: 07/21/2013] [Indexed: 06/02/2023]
Abstract
Herein, the effect of amino acid Glutathione (GSH) on Peroxyoxalate Chemiluminescence was studied for the first time. Hypericin (HYP) was employed as the efficient fluorophore. The investigated parameters included rise and fall rate constant for the chemiluminescence burst, theoretical and experimental maximum intensity, the time-needed to reach maximum intensity and the total light yield emission which theoretically was evaluated using the pooled intermediate model by a computerized non-linear least-squares curve fitting program (KINFIT). Furthermore, based on observed quenching effect of GSH, the Stern-Volmer plot in quencher concentration range of 2.8×10(-6) to 3.4×10(-5)M with KQ value of 1.59×10(4) was calculated. The bimolecular quenching rate constant (Kq) was also estimated about 2.8×10(12) and M(-1) S(-1). Moreover the system was applied successfully to determine glutathione in biological samples.
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Affiliation(s)
- Sayed Yahya Kazemi
- Department of Basic Sciences, Sari Agricultural Sciences and Natural Resources University, P.O. Box 578, Sari, Iran
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2
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Ciogli A, Bicker W, Lindner W. Determination of enantiomerization barriers of hypericin and pseudohypericin by dynamic high-performance liquid chromatography on immobilized polysaccharide-type chiral stationary phases and off-column racemization experiments. Chirality 2010; 22:463-71. [PMID: 19644936 DOI: 10.1002/chir.20764] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Direct enantiomer separation of hypericin, pseudohypericin, and protohypericin was accomplished by high-performance liquid chromatography (HPLC) using immobilized polysaccharide-type chiral stationary phases (CSPs). Enantioselectivities up to 1.30 were obtained in the polar-organic elution mode whereby for hypericin and pseudohypericin Chiralpak IC [chiral selector being cellulose tris(3,5-dichlorophenylcarbamate)] and for protohypericin Chiralpak IA (chiral selector being the 3,5-dimethylphenylcarbamate of amylose) gave favorable results. Enantiomers were distinguished by on-line electronic circular dichroism detection. Optimized enantioselective chromatographic conditions were the basis for determining stereodynamic parameters of the enantiomer interconversion process of hypericin and pseudohypericin. Rate constants delivered by computational simulation of dynamic HPLC elution profiles (stochastic model, consideration of peak tailing) were used to calculate averaged enantiomerization barriers (DeltaG(enant)(#)) of 97.6-99.6 kJ/mol for both compounds (investigated temperature range 25-45 degrees C). Complementary variable temperature off-column (i.e., in solution) racemization experiments delivered DeltaG(enant)(#) = 97.1-98.0 kJ/mol (27-45 degrees C) for hypericin and DeltaG(enant)(#) = 98.9-101.4 kJ/mol (25-55 degrees C) for pseudohypericin. An activation enthalpy of DeltaH(#) = 86.0 kJ/mol and an activation entropy of DeltaS(#) = -37.7 J/(K mol) were calculated from hypericin racemization kinetics in solution, whereas for pseudohypericin these figures amounted to 74.1 kJ/mol and -82.6 J/(K mol), respectively. Although the natural phenanthroperylene quinone pigments hypericin and pseudohypericin as well as their biological precursor protohypericin are chiral and can be separated by enantioselective HPLC low enantiomerization barriers seem to prevent the occurrence of an excess of one enantiomer under typical physiological conditions--at least as long as stereoselective intermolecular interactions with other chiral entities are absent.
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Affiliation(s)
- Alessia Ciogli
- Department of Analytical Chemistry and Food Chemistry, University of Vienna, Vienna, Austria
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3
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Sanders L, Halder M, Xiao TL, Ding J, Armstrong DW, Petrich JW. The Separation of Hypericin's Enantiomers and Their Photophysics in Chiral Environments¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01539.x] [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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4
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Rahimipour S, Palivan C, Freeman D, Barbosa F, Fridkin M, Weiner L, Mazur Y, Gescheidt G. Hypericin Derivatives: Substituent Effects on Radical-anion Formation. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740149hdseor2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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5
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Wen J, Chowdhury P, Fulton DB, Datta A, Das K, Andreotti AH, Petrich JW. Does Solvent Influence the Ground-state Tautomeric Population of Hypericin?¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0770005dsitgs2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Showalter BM, Datta A, Chowdhury PK, Park J, Bandyopadhyay P, Choudhury PK, Kesavan S, Zeng Y, Kraus GA, Gordon MS, Toscano JP, Petrich JW. Identification of a Vibrational Frequency Corresponding to H-atom Translocation in Hypericin¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740157ioavfc2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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7
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Freeman D, Konstantinovskii L, Mazur Y. The Structure of Hypericin in Solution. Searching for Hypericin's 1,6 Tautomer¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740206tsohis2.0.co2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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8
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Zhang HY, Liu W, Liu WZ, Xie JL. Photosensitization of Hypomycin B-A Novel Perylenequinonoid Pigment with Only One Intramolecular Hydrogen Bond¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740191pohban2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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Krishnamoorthy G, Webb SP, Nguyen T, Chowdhury PK, Halder M, Wills NJ, Carpenter S, Kraus GA, Gordon MS, Petrich JW. Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01464.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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Yi PG, Liang YH. Theoretical studies of conjugation and substituent effect on intramolecular proton transfer in the ground and excited states. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.09.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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11
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Webb SP. Ab initio electronic structure theory as an aid to understanding excited state hydrogen transfer in moderate to large systems. Theor Chem Acc 2005. [DOI: 10.1007/s00214-005-0011-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Wang LF, Zhang HY. A theoretical study on physicochemical properties of elsinochrome A in ground state. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.theochem.2005.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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13
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Plaza P, Mahet M, Tchaikovskaya ON, Martin MM. Excitation energy effect on the early photophysics of hypericin in solution. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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15
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Li P, Bu Y. Double proton transfer and one-electron oxidation behavior in double H-bonded glycinamide-glycine complex in the gas phase. J Comput Chem 2005; 26:552-60. [PMID: 15726572 DOI: 10.1002/jcc.20191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The behaviors of double proton transfer (DPT) occurring in a representative glycinamide-glycine complex have been investigated employing the B3LYP/6-311++G** level of theory. Thermodynamic and especially kinetic parameters, such as tautomerization energy, equilibrium constant, and barrier heights have been discussed, respectively. The relevant quantities involved in the DPT process including geometrical changes, interaction energies, and deformation energies have also been studied. Analogous to that of tautomeric process assisted with a formic acid molecule, the participation of a glycine molecule favors the proceeding of the proton transfer (PT) for glycinamide compared with that without mediator-assisted case. The DPT process proceeds with a concerted mechanism rather than a stepwise one because no zwitterionic complexes have been located during the DPT process. The barrier heights are 12.14 and 0.83 kcal/mol for the forward and reverse directions, respectively. However, both of them have been reduced by 3.10 and 2.66 kcal/mol to 9.04 and -1.83 kcal/mol with further inclusion of zero-point vibrational energy (ZPVE) corrections, where the disappearance of the reverse barrier height implies that the reverse reaction should proceed with barrierless spontaneously, analogous to those of DPTs occurring between glycinamide and formic acid (or formamide). Additionally, the oxidation process for the double H-bonded glycinamide-glycine complex has also been investigated. The oxidated product is characterized by a distonic radical cation due to the fact that one-electron oxidation takes place on glycine fragment and a proton has been transferred from glycine to glycinamide fragment spontaneously. As a result, the vertical and adiabatic ionization potentials for the neutral complex have been determined to be about 8.71 and 7.85 eV, respectively, where both of them have been reduced by about 0.54 (1.11) and 0.75 (1.13) eV relative to those of isolated glycinamide (glycine) due to the formation of the intermolecular H-bond.
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Affiliation(s)
- Ping Li
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Repubic of China
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16
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Sanders L, Halder M, Xiao TL, Ding J, Armstrong DW, Petrich JW. The Separation of Hypericin's Enantiomers and Their Photophysics in Chiral Environments¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-05-28-rn-181.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Krishnamoorthy G, Webb SP, Nguyen T, Chowdhury PK, Halder M, Wills NJ, Carpenter S, Kraus GA, Gordon MS, Petrich JW. Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-11-23-ra-378r1.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Li P, Bu Y. Double proton transfer behavior and one-electron oxidation effect in double H-bonded glycinamide-formic acid complex. J Chem Phys 2004; 121:9971-81. [PMID: 15549872 DOI: 10.1063/1.1792111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The behavior of double proton transfer occurring in a representative glycinamide-formic acid complex has been investigated at the B3LYP/6-311 + + G( * *) level of theory. Thermodynamic and, especially, kinetic parameters, such as tautomeric energy, equilibrium constant, and barrier heights have been discussed, respectively. The relevant quantities involved in the double proton transfer process, such as geometrical changes, interaction energies, and intrinsic reaction coordinate calculations have also been studied. Computational results show that the participation of a formic acid molecule favors the proceeding of the proton transfer for glycinamide compared with that without mediate-assisted case. The double proton transfer process proceeds with a concerted mechanism rather than a stepwise one since no ion-pair complexes have been located during the proton transfer process. The calculated barrier heights are 11.48 and 0.85 kcal/mol for the forward and reverse directions, respectively. However, both of them have been reduced by 2.95 and 2.61 kcal/mol to 8.53 and -1.76 kcal/mol if further inclusion of zero-point vibrational energy corrections, where the negative barrier height implies that the reverse reaction should proceed with barrierless spontaneously, analogous to that occurring between glycinamide and formamide. Furthermore, solvent effects on the thermodynamic and kinetic processes have also been predicted qualitatively employing the isodensity surface polarized continuum model within the framework of the self-consistent reaction field theory. Additionally, the oxidation process for the double H-bonded glycinamide-formic acid complex has also been investigated. Contrary to that neutral form possessing a pair of two parallel intermolecular H bonds, only a single H bond with a comparable strength has been found in its ionized form. The vertical and adiabatic ionization potentials for the neutral complex have been determined to be about 9.40 and 8.69 eV, respectively, where ionization is mainly localized on the glycinamide fragment. Like that ionized glycinamide-formamide complex, the proton transfer in the ionized complex is characterized by a single-well potential, implying that the proton initially attached to amide N4 in the glycinamide fragment cannot be transferred to carbonyl O13 in the formic acid fragment at the geometry of the optimized complex.
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Affiliation(s)
- Ping Li
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China
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19
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Li P, Bu Y. Investigations of Double Proton Transfer Behavior between Glycinamide and Formamide Using Density Functional Theory. J Phys Chem A 2004. [DOI: 10.1021/jp048527b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ping Li
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, P. R. China, and Department of Chemistry, Qufu Normal University, Qufu 273165, P. R. China
| | - Yuxiang Bu
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, P. R. China, and Department of Chemistry, Qufu Normal University, Qufu 273165, P. R. China
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20
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Li P, Bu Y, Ai H, Yan S, Han K. Double Proton Transfer and One-Electron Oxidation Behaviors in Double H-Bonded Glycinamide−Formamidine Complex and Comparison with Biological Base Pair. J Phys Chem B 2004. [DOI: 10.1021/jp047567c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ping Li
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China, Department of Chemistry, Qufu Normal University, Qufu 273165, People's Republic of China, and State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Science Academy of China, Dalian, 116023, People's Republic of China
| | - Yuxiang Bu
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China, Department of Chemistry, Qufu Normal University, Qufu 273165, People's Republic of China, and State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Science Academy of China, Dalian, 116023, People's Republic of China
| | - Hongqi Ai
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China, Department of Chemistry, Qufu Normal University, Qufu 273165, People's Republic of China, and State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Science Academy of China, Dalian, 116023, People's Republic of China
| | - Shihai Yan
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China, Department of Chemistry, Qufu Normal University, Qufu 273165, People's Republic of China, and State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Science Academy of China, Dalian, 116023, People's Republic of China
| | - Keli Han
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China, Department of Chemistry, Qufu Normal University, Qufu 273165, People's Republic of China, and State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Science Academy of China, Dalian, 116023, People's Republic of China
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21
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Kong L, Indira Priyadarsini K, Zhang HY. A theoretical investigation on intramolecular hydrogen-atom transfer in curcumin. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2004.06.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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22
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Wang DP, Chen SG, Chen DZ. Theoretical studies of conjugate and substituent effects on the intramolecular proton transfer: an HF/CIS study. J Photochem Photobiol A Chem 2004. [DOI: 10.1016/s1010-6030(03)00382-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Shen YX, Wang XL, Liu WZ, Zhang HY. An exploratory theoretical investigation on intramolecular proton transfer in a novel perylenequinonoid pigment-hypomycin A. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2003.10.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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24
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Wen J, Chowdhury P, Fulton DB, Datta A, Das K, Andreotti AH, Petrich JW. Does solvent influence the ground-state tautomeric population of hypericin? Photochem Photobiol 2003; 77:5-9. [PMID: 12856875 DOI: 10.1562/0031-8655(2003)077<0005:dsitgs>2.0.co;2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nuclear magnetic resonance measurements indicate that hypericin exists in the same "normal" tautomeric form irrespective of whether the solvent is dimethyl sulfoxide or tetrahydrofuran. This result is discussed in the context of previous experimental and theoretical work. It is concluded that solvent perturbations cannot induce tautomerization in hypericin.
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Affiliation(s)
- J Wen
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA
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25
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Chowdhury P, Das K, Datta A, Liu WZ, Zhang HY, Petrich J. A comparison of the excited-state processes of nearly symmetrical perylene quinones: hypocrellin A and hypomycin B. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(02)00309-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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26
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Skalkos D, Tatsis E, Gerothanassis IP, Troganis A. Towards a consensus structure of hypericin in solution: direct evidence for a single tautomer and different ionization states in protic and nonprotic solvents by the use of variable temperature gradient 1H NMR. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)00419-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Freeman D, Konstantinovskii L, Mazur Y. The structure of hypericin in solution. Searching for hypericin's 1,6 tautomer. Photochem Photobiol 2001; 74:206-10. [PMID: 11547556 DOI: 10.1562/0031-8655(2001)074<0206:tsohis>2.0.co;2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hypericin in organic solvents displays two types of electronic spectra: one type which shows a distinct solvatochromic effect, the stable form, and the other, the unstable form, which lacks this property. The latter type is formed in dry nonprotic solvents (e.g. tetrahydrofuran, EtOAc) and can be converted to the stable form on addition of protic solvents. In order to establish the tautomeric structure of the unstable form we applied conventional nuclear magnetic resonance techniques as well as two-dimensional gradient-enhanced heteronuclear multiple-quantum correlation, gradient-enhanced ROESY and one-dimensional nuclear Overhauser effect difference experiments. All these techniques pointed to the fact that the unstable form has the 7,14-diketo tautomeric structure, like the stable form, and not the 1,6-diketo structure. Electronic spectroscopy indicated that the unstable form has acidic properties and therefore possesses two free OH groups at C3 and C4 at the bay region of the molecule.
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Affiliation(s)
- D Freeman
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
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28
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Rahimipour S, Palivan C, Freeman D, Barbosa F, Fridkin M, Weiner L, Mazur Y, Gescheidt G. Hypericin derivatives: substituent effects on radical-anion formation. Photochem Photobiol 2001; 74:149-56. [PMID: 11547548 DOI: 10.1562/0031-8655(2001)074<0149:hdseor>2.0.co;2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The electron-transfer properties of the hypericin derivatives, dibromo-, hexaacetyl-, hexamethyl- and desmethylhypericin, were studied. Cyclovoltammetric measurements revealed that dibromo- and desmethylhypericin have almost the same redox potentials as the parent hypericin. Substitution of the hydroxyl groups by acetoxy leads to less negative E1/2 values, whereas methoxy substitution induces more negative values. Electron paramagnetic resonance (EPR)/electron nuclear double resonance/general TRIPLE spectroscopy and quantum mechanical calculations were used to establish the structure of the one-electron reduced stages of hypericin derivatives. Proton loss in the bay region, already demonstrated for hypericin, was also found for dibromo- and desmethylhypericin. The spin and charge of the radical ions are predominately confined to the central biphenoquinone moiety of the hypericin skeleton. Generation of the radical ions by in situ electrolysis indicates that the redox potentials of hypericin, dibromo- and desmethylhypericin, containing hydroxyls at the 1, 3, 4, 6, 8 and 13 positions, largely depend on the solvent. With phosphate-buffered saline (pH 7.4)/dimethylsulfoxide (DMSO) as the solvent the EPR spectra of the corresponding radical ions appear at markedly lower potentials than in pure DMSO and N,N'-dimethylformamide. However, this effect is not observable for hexaacetyl- and hexamethyl-hypericin-lacking hydroxyl groups. In all cases the EPR data and calculations revealed the presence of 7,14 tautomers.
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Affiliation(s)
- S Rahimipour
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
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29
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Showalter BM, Datta A, Chowdhury PK, Park J, Bandyopadhyay P, Choudhury PK, Kesavan S, Zeng Y, Kraus GA, Gordon MS, Toscano JP, Petrich JW. Identification of a vibrational frequency corresponding to H-atom translocation in hypericin. Photochem Photobiol 2001; 74:157-63. [PMID: 11547549 DOI: 10.1562/0031-8655(2001)074<0157:ioavfc>2.0.co;2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Using time-resolved infrared spectroscopy, ab initio quantum mechanical calculations and synthetic organic chemistry a region in the infrared spectrum of triplet hypericin has been found between 1400 and 1500 cm-1 corresponding to the translocation of the hydrogen atom between the enol and the keto oxygens, O...H...O. This result is discussed in the context of the photophysics of hypericin and of eventual measurements to observe directly the excited-state H-atom transfer.
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Affiliation(s)
- B M Showalter
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA
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30
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Zhang HY, Liu W, Liu WZ, Xie JL. Photosensitization of hypomycin B--a novel perylenequinonoid pigment with only one intramolecular hydrogen bond. Photochem Photobiol 2001; 74:191-5. [PMID: 11547553 DOI: 10.1562/0031-8655(2001)074<0191:pohban>2.0.co;2] [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: 11/19/2022]
Abstract
Electron spin resonance technique and spin-trapping methods were used to determine the photoproduction of 1O2 and O2.- by hypomycin B (HMB), a novel perylenequinonoid pigment (PQP) possessing only one hydroxyl group. It was found that the yields of 1O2 and O2.- for HMB were comparable to those for hypocrellin A, a typical natural PQP with good photosensitivity. In addition, the absorption and fluorescence spectra for HMB were investigated. The pKa values in the ground and excited states of HMB were determined to be 8.94 and 5.54, respectively. Thus, the photodynamic mechanisms of HMB may involve not only the photogeneration of 1O2 and O2.- but also the light-induced acidification. Consequently, HMB is proposed to be a good photodynamic therapeutic agent.
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Affiliation(s)
- H Y Zhang
- Laboratory for Computational Biology, Shandong Provincial Research Center for Bioinformatic Engineering and Technique, Zibo University, Zibo, People's Republic of China.
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Datta A, Smirnov AV, Wen J, Chumanov G, Petrich JW. Multidimensional reaction coordinate for the excited-state H-atom transfer in perylene quinones: importance of the 7-membered ring in hypocrellins A and B. Photochem Photobiol 2000. [PMID: 10687390 DOI: 10.1562/0031-8655(2000)0710166mrcfte2.0.co2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The excited-state intramolecular H-atom transfer reactions of hypocrellins B and A are compared by using time-resolved absorption and fluorescence upconversion techniques. The hypocrellin B photophysics are well described by a simple model involving one ground-state species and excited-state forward and reverse H-atom transfer with a nonfluorescent excited state. We suggest that excited-state conformational changes are coupled to the H-atom transfer in hypocrellin B just as gauche/anti changes are coupled to the H-atom transfer in hypocrellin A.
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Affiliation(s)
- A Datta
- Department of Chemistry, Iowa State University, Ames 50011, USA
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Uličný J, Laaksonen A. Hypericin, an intriguing internally heterogenous molecule, forms a covalent intramolecular hydrogen bond. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00178-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Smirnov AV, Das K, English DS, Wan Z, Kraus GA, Petrich JW. Excited-State Intramolecular H Atom Transfer of Hypericin and Hypocrellin A Investigated by Fluorescence Upconversion. J Phys Chem A 1999. [DOI: 10.1021/jp992436a] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- A. V. Smirnov
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - K. Das
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - D. S. English
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Z. Wan
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - G. A. Kraus
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - J. W. Petrich
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
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Smirnov A, Fulton DB, Andreotti A, Petrich JW. Exploring Ground-State Heterogeneity of Hypericin and Hypocrellin A and B: Dynamic and 2D ROESY NMR Study. J Am Chem Soc 1999. [DOI: 10.1021/ja9906002] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. Smirnov
- Contribution from the Department of Chemistry and the Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - D. B. Fulton
- Contribution from the Department of Chemistry and the Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - A. Andreotti
- Contribution from the Department of Chemistry and the Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - J. W. Petrich
- Contribution from the Department of Chemistry and the Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011
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Darmanyan AP, Jenks WS, Eloy D, Jardon P. Quenching of Excited Triplet State Hypericin with Energy Acceptors and Donors and Acceptors of Electrons. J Phys Chem B 1999. [DOI: 10.1021/jp984030o] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Das K, Ashby KD, Wen J, Petrich JW. Temperature Dependence of the Excited-State Intramolecular Proton Transfer Reaction in Hypericin and Hypocrellin A. J Phys Chem B 1999. [DOI: 10.1021/jp982728w] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K. Das
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - K. D. Ashby
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - J. Wen
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - J. W. Petrich
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
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