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Mandal D, Maity R, Mandal U, Salgado-Morán G, Misra A. Computation of electrical responsive properties and global reactivity descriptors along the proton transfer co-ordinate of donor–acceptor substituted pyrazole derivatives. Mol Phys 2021. [DOI: 10.1080/00268976.2020.1811413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Debkumar Mandal
- Department of Chemistry, Vidyasagar University, Midnapore, India
| | - Rakesh Maity
- Department of Chemistry, Vidyasagar University, Midnapore, India
| | - Usha Mandal
- Department of Chemistry, Vidyasagar University, Midnapore, India
| | - Guillermo Salgado-Morán
- Departamento de Ciencias Qumícas, Facultad de Ciencias Exactas, Universidad Andrés Bello, Concepción, Chile
| | - Ajay Misra
- Department of Chemistry, Vidyasagar University, Midnapore, India
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Liu Q, Wackenhut F, Wang L, Hauler O, Roldao JC, Adam PM, Brecht M, Gierschner J, Meixner AJ. Direct Observation of Structural Heterogeneity and Tautomerization of Single Hypericin Molecules. J Phys Chem Lett 2021; 12:1025-1031. [PMID: 33470816 DOI: 10.1021/acs.jpclett.0c03459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Tautomerization is a fundamental chemical reaction which involves the relocation of a proton in the reactants. Studying the optical properties of tautomeric species is challenging because of ensemble averaging. Many molecules, such as porphines, porphycenes, or phenanthroperylene quinones, exhibit a reorientation of the transition dipole moment (TDM) during tautomerization, which can be directly observed in single-molecule experiments. Here, we study single hypericin molecules, which is a prominent phenanthroperylene quinone showing antiviral, antidepressive, and photodynamical properties. Observing abrupt flipping of the image pattern combined with time-dependent density functional theory calculations allows drawing conclusions about the coexistence of four tautomers and their conversion path. This approach allows the unambiguous assignment of a TDM orientation to a specific tautomer and enables the determination of the chemical structure in situ. Our approach can be applied to other molecules showing TDM reorientation during tautomerization, helping to gain a deeper understanding of this important process.
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Affiliation(s)
- Quan Liu
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Laboratoire Lumière, Nanomatériaux & Nanotechnologies - L2n and CNRS ERL 7004, Universitéde Technologie de Troyes, 10000 Troyes, France
| | - Frank Wackenhut
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Liangxuan Wang
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco, C/Faraday 9, 28049 Madrid, Spain
| | - Otto Hauler
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Reutlingen Research Institute, Process Analysis and Technology (PA&T), Reutlingen University, Alteburgstraße 150, 72762 Reutlingen, Germany
| | - Juan Carlos Roldao
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco, C/Faraday 9, 28049 Madrid, Spain
| | - Pierre-Michel Adam
- Laboratoire Lumière, Nanomatériaux & Nanotechnologies - L2n and CNRS ERL 7004, Universitéde Technologie de Troyes, 10000 Troyes, France
| | - Marc Brecht
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Reutlingen Research Institute, Process Analysis and Technology (PA&T), Reutlingen University, Alteburgstraße 150, 72762 Reutlingen, Germany
| | - Johannes Gierschner
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco, C/Faraday 9, 28049 Madrid, Spain
| | - Alfred J Meixner
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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Gu D, Yang W, Ning G, Wang F, Wu S, Shi X, Wang Y, Pan Q. In Situ Ligand Formation-Driven Synthesis of a Uranyl Organic Framework as a Turn-on Fluorescent pH Sensor. Inorg Chem 2020; 59:1778-1784. [PMID: 31950823 DOI: 10.1021/acs.inorgchem.9b02999] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A uranium-based metal-organic framework, [(UO2)(H2DTATC)] (HNU-39, H4DTATC = 5,5'-(9,10-dihydroxy-4a,9,9a,10-tetrahydroanthracene-9,10-diyl)diisophthalic acid) was successfully prepared by a hydrothermal method. The structure of HNU-39 comprises UO8 hexagonal bipyramids linked by doubly protonated DTATC ligands, forming a ribbon arrangement. It is worth noting that the DTATC ligand was transformed in situ from 5,5'-(anthracene-9,10-diyl)diisophthalic acid (H4DPATC) during the synthesis of HNU-39. Research on fluorescence properties has shown that HNU-39 exhibits fluorescence turn-on response under alkaline conditions and could be used as a potential pH sensor. Moreover, HNU-39 can also be successfully applied for pH sensing in real samples from a sewage treatment plant. The sensing mechanism can be interpreted as OH- ions reacting with the protons in the organic ligand of HNU-39.
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Affiliation(s)
- Dongxu Gu
- Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, School of Science , Hainan University , Haikou , 570228 , People's Republic of China
| | - Weiting Yang
- Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, School of Science , Hainan University , Haikou , 570228 , People's Republic of China
| | - Guohua Ning
- Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, School of Science , Hainan University , Haikou , 570228 , People's Republic of China
| | - Fuxiang Wang
- Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, School of Science , Hainan University , Haikou , 570228 , People's Republic of China
| | - Shuixing Wu
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province, School of Chemistry and Chemical Engineering , Hainan Normal University , Haikou 571158 , People's Republic of China
| | - Xiaodong Shi
- Department of Chemistry , University of South Florida , 4202 East Fowler Avenue , Tampa , Florida 33620 , United States
| | - Yinghui Wang
- State Key Laboratory of Rare Earth Resource Utilization , Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , 5625 Renmin Street , Changchun , Jilin 130022 , People's Republic of China
| | - Qinhe Pan
- Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, School of Science , Hainan University , Haikou , 570228 , People's Republic of China
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Shedding new light on an old molecule: quinophthalone displays uncommon N-to-O excited state intramolecular proton transfer (ESIPT) between photobases. Sci Rep 2017. [PMID: 28634405 PMCID: PMC5478638 DOI: 10.1038/s41598-017-04114-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Excited state dynamics of common yellow dye quinophthalone (QPH) was probed by femtosecond transient absorption spectroscopy. Multi-exponential decay of the excited state and significant change of rate constants upon deuterium substitution indicate that uncommon nitrogen-to-oxygen excited state intramolecular proton transfer (ESIPT) occurs. By performing density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations, we found that adiabatic surface crossing between the S1 and S2 states takes place in the photoreaction. Unlike most cases of ESIPT, QPH does not exhibit tautomer emission, possibly due to internal conversion or back-proton transfer. The ESIPT of QPH presents a highly interesting case also because the moieties participating in ESIPT, quinoline and aromatic carbonyl, are both traditionally considered as photobases.
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Jana S, Dalapati S, Guchhait N. Functional group induced excited state intramolecular proton transfer process in 4-amino-2-methylsulfanyl-pyrimidine-5-carboxylic acid ethyl ester: a combined spectroscopic and density functional theory study. Photochem Photobiol Sci 2013; 12:1636-48. [DOI: 10.1039/c3pp50010a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Patil VS, Padalkar VS, Phatangare KR, Gupta VD, Umape PG, Sekar N. Synthesis of New ESIPT-Fluorescein: Photophysics of pH Sensitivity and Fluorescence. J Phys Chem A 2011; 116:536-45. [DOI: 10.1021/jp2073123] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vikas S. Patil
- Institute of Chemical Technology (Formerly UDCT), N. P. Marg, Matunga, Mumbai, 400 019 Maharashtra, India
| | - Vikas S. Padalkar
- Institute of Chemical Technology (Formerly UDCT), N. P. Marg, Matunga, Mumbai, 400 019 Maharashtra, India
| | - Kiran R. Phatangare
- Institute of Chemical Technology (Formerly UDCT), N. P. Marg, Matunga, Mumbai, 400 019 Maharashtra, India
| | - Vinod D. Gupta
- Institute of Chemical Technology (Formerly UDCT), N. P. Marg, Matunga, Mumbai, 400 019 Maharashtra, India
| | - Prashant G. Umape
- Institute of Chemical Technology (Formerly UDCT), N. P. Marg, Matunga, Mumbai, 400 019 Maharashtra, India
| | - Nagaiyan Sekar
- Institute of Chemical Technology (Formerly UDCT), N. P. Marg, Matunga, Mumbai, 400 019 Maharashtra, India
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Kee TW, Adhikary R, Carlson PJ, Mukherjee P, Petrich JW. Femtosecond Fluorescence Upconversion Investigations on the Excited-State Photophysics of Curcumin. Aust J Chem 2011. [DOI: 10.1071/ch10417] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The demonstration of curcumin as a photodynamic therapy agent has generated a high level of interest in understanding the photoinduced chemical and physical properties of this naturally occurring, yellow-orange medicinal compound. Important photophysical processes that may be related to photodynamic therapy effects including excited-state intramolecular hydrogen atom transfer (ESIHT) occur within the femtosecond to picosecond time scales. Femtosecond fluorescence upconversion spectroscopy has sufficient time resolution to resolve and investigate these important photophysical processes. In this review, recent advances in using femtosecond fluorescence upconversion to reveal ultrafast solvation and ESIHT of curcumin are presented. The excited-state photophysics of curcumin has been investigated in alcohols and micellar solutions. The results of curcumin in methanol and ethylene glycol reveal the presence of two decay components in the excited-state kinetics with time scales of 12–20 ps and ∼100 ps. Similarly, in a micellar solution, biphasic kinetics are present with the fast decay component having a time constant of 3–8 ps, the slow decay component 50–80 ps. Deuteration of curcumin in both media leads to a pronounced isotope effect in the slow decay component, which suggests that ESIHT is an important photophysical process on this time scale. The results of multiwavelength fluorescence upconversion studies show that the fast component in the excited-state kinetics is due to ultrafast solvation. These advances form a part of the continuing efforts to elucidate the photodynamic therapy properties of curcumin.
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Adhikary R, Carlson PJ, Kee TW, Petrich JW. Excited-state intramolecular hydrogen atom transfer of curcumin in surfactant micelles. J Phys Chem B 2010; 114:2997-3004. [PMID: 20136104 DOI: 10.1021/jp9101527] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Femtosecond fluorescence upconversion experiments were performed on the naturally occurring medicinal pigment, curcumin, in anionic, cationic, and neutral micelles. In our studies, the micelles are composed of sodium dodecyl sulfate (SDS), dodecyl trimethyl ammonium bromide (DTAB), and triton X-100 (TX-100). We demonstrate that the excited-state kinetics of curcumin in micelles have a fast (3-8 ps) and slow (50-80 ps) component. While deuteration of curcumin has a negligible effect on the fast component, the slow component exhibits a pronounced isotope effect of approximately 1.6, indicating that micelle-captured curcumin undergoes excited-state intramolecular hydrogen atom transfer. Studies of solvation dynamics of curcumin in a 10 ps time window reveal a fast component (< or = 300 fs) followed by a 8, 6, and 3 ps component in the solvation correlation function for the TX-100, DTAB, and SDS micelles, respectively.
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Hypericins as potential leads for new therapeutics. Int J Mol Sci 2010; 11:562-94. [PMID: 20386655 PMCID: PMC2852855 DOI: 10.3390/ijms11020562] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 01/27/2010] [Accepted: 01/28/2010] [Indexed: 12/22/2022] Open
Abstract
70 years have passed since the first isolation of the naphthodianthrones hypericin and pseudohypericin from Hypericum perforatum L. Today, they continue to be one of the most promising group of polyphenols, as they fascinate with their physical, chemical and important biological properties which derive from their unique chemical structure. Hypericins and their derivatives have been extensively studied mainly for their antitumor, antiviral and antidepressant properties. Notably, hypericin is one of the most potent naturally occurring photodynamic agents. It is able to generate the superoxide anion and a high quantum yield of singlet oxygen that are considered to be primarily responsible for its biological effects. The prooxidant photodynamic properties of hypericin have been exploited for the photodynamic therapy of cancer (PDT), as hypericin, in combination with light, very effectively induces apoptosis and/or necrosis of cancer cells. The mechanism by which these activities are expressed continues to be a main topic of discussion, but according to scientific data, different modes of action (generation of ROS & singlet oxygen species, antiangiogenesis, immune responces) and multiple molecular pathways (intrinsic/extrinsic apoptotic pathway, ERK inhibition) possibly interrelating are implicated. The aim of this review is to analyse the most recent advances (from 2005 and thereof) in the chemistry and biological activities (in vitro and in vivo) of the pure naphthodianthrones, hypericin and pseudohypericin from H. perforatum. Extracts from H. perforatum were not considered, nor pharmakokinetic or clinical data. Computerised literature searches were performed using the Medline (PubMed), ChemSciFinder and Scirus Library databases. No language restrictions were imposed.
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Adhikary R, Mukherjee P, Kee TW, Petrich JW. Excited-State Intramolecular Hydrogen Atom Transfer and Solvation Dynamics of the Medicinal Pigment Curcumin. J Phys Chem B 2009; 113:5255-61. [DOI: 10.1021/jp901234z] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Ramkrishna Adhikary
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, and School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Prasun Mukherjee
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, and School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Tak W. Kee
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, and School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Jacob W. Petrich
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111, and School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia, 5005, Australia
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Wen ZC, Ferreira JA, Costa SM. Novel pH tunable fluorescent sensor with dual recognition mode. J Photochem Photobiol A Chem 2008. [DOI: 10.1016/j.jphotochem.2008.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ley C, Brazard J, Lacombat F, Plaza P, Martin MM, Kraus GA, Petrich JW. Multiphotonic excitation and solvation dynamics effects on the femtosecond transient absorption of O-hexamethoxyhypericin. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.03.066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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English DS, Doyle RT, Petrich JW, Haydon PG. Subcellular Distributions and Excited-State Processes of Hypericin in Neurons. Photochem Photobiol 2008. [DOI: 10.1111/j.1751-1097.1999.tb03290.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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Lobban CS, Hallam SJ, Mukherjee P, Petrich JW. Photophysics and Multifunctionality of Hypericin-Like Pigments in Heterotrich Ciliates: A Phylogenetic Perspective. Photochem Photobiol 2007; 83:1074-94. [PMID: 17880503 DOI: 10.1111/j.1751-1097.2007.00191.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper, we review the literature and present some new data to examine the occurrence and photophysics of the diverse hypericin-like chromophores in heterotrichs, the photoresponses of the cells, the various roles of the pigments and the taxa that might be studied to advance our understanding of these pigments. Hypericin-like chromophores are known chemically and spectrally so far only from the stentorids and Fabrea, the latter now seen to be sister to stentorids in the phylogenetic tree. For three hypericin-like pigments, the structures are known but these probably do not account for all the colors seen in stentorids. At least eight physiological groups of Stentor exist depending on pigment color and presence/absence of zoochlorellae, and some species can be bleached, leading to many opportunities for comparison of pigment chemistry and cell behavior. Several different responses to light are exhibited among heterotrichs, sometimes by the same cell; in particular, cells with algal symbionts are photophilic in contrast to the well-studied sciaphilous (shade-loving) species. Hypericin-like pigments are involved in some well-known photophobic reactions but other pigments (rhodopsin and flavins) are also involved in photoresponses in heterotrichs and other protists. The best characterized role of hypericin-like pigments in heterotrichs is in photoresponses and they have at least twice evolved a role as photoreceptors. However, hypericin and hypericin-like pigments in diverse organisms more commonly serve as predator defense and the pigments are multifunctional in heterotrichs. A direct role for the pigments in UV protection is possible but evidence is equivocal. New observations are presented on a folliculinid from deep water, including physical characterization of its hypericin-like pigment and its phylogenetic position based on SSU rRNA sequences. The photophysics of hypericin and hypericin-like pigments is reviewed. Particular attention is given to how their excited-state properties are modified by the environment. Dramatic changes in excited-state behavior are observed as hypericin is moved from the homogeneous environment of organic solvents to the much more structured surroundings provided by the complexes it forms with proteins. Among these complexes, it is useful to consider the differences between environments where hypericin is not found naturally and those where it is, notably, for example, in heterotrichs. It is clear that interaction with a protein modifies the photophysics of hypericin and understanding the molecular basis of this interaction is one of the outstanding problems in elucidating the function of hypericin and hypericin-like chromophores.
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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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Wen J, Chowdhury P, Wills NJ, Wannemuehler Y, Park J, Kesavan S, Carpenter S, Kraus GA, Petrich JW. Toward the Molecular Flashlight: Preparation, Properties, and Photophysics of a Hypericin-luciferin Tethered Molecule¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0760153ttmfpp2.0.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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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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Xu S, Tian C, Chen S, Zhang M, Shen T. Photobleaching of Hypocrellin B and its Butylamino-substituted Derivative in Solutions. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740184pohbai2.0.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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Weitman H, Roslaniec M, Frimer AA, Afri M, Freeman D, Mazur Y, Ehrenberg B. Solvatochromic Effects in the Electronic Absorption and Nuclear Magnetic Resonance Spectra of Hypericin in Organic Solvents and in Lipid Bilayers¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0730110seitea2.0.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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Park J, Datta A, Chowdhury PK, Petrich JW. Is the Excited-State H-atom Transfer in Hypericin Concerted?¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0730105itesha2.0.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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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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Xu S, Zhang X, Chen S, Zhang M, Shen T. The Fluorescence Properties of Hypocrellin B and its Amino-substituted Derivative: Photinduced Intramolecular Proton Transfer and Photoinduced Intramolecular Electron Transfer¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2004.tb00057.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Halder M, Chowdhury PK, Das R, Mukherjee P, Atkins WM, Petrich JW. Interaction of Glutathione S-Transferase with Hypericin: A Photophysical Study. J Phys Chem B 2005; 109:19484-9. [PMID: 16853517 DOI: 10.1021/jp051645u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photophysics of hypericin have been studied in its complex with two different isoforms, A1-1 and P1-1, of the protein glutathione S-transferase (GST). One molecule of hypericin binds to each of the two GST subunits. Comparisons are made with our previous results for the hypericin/human serum albumin complex (Photochem. Photobiol. 1999, 69, 633-645). Hypericin binds with high affinity to the GSTs: 0.65 microM for the A1-1 isoform and 0.51 microM for the P1-1 isoform (Biochemistry 2004, 43, 12761-12769). The photophysics and activity of hypericin are strongly modulated by the binding protein. Intramolecular hydrogen-atom transfer is suppressed in both cases. Most importantly, while there is significant singlet oxygen generation from hypericin bound to GST A1-1, binding to GST P1-1 suppresses singlet oxygen generation to almost negligible levels. The data are rationalized in terms of a simple model in which the hypericin photophysics depends entirely upon the decay of the triplet state by two competing processes, quenching by oxygen to yield singlet oxygen and ionization, the latter of these two are proposed to be modulated by A1-1 and P1-1.
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Affiliation(s)
- M Halder
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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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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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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Excited state intramolecular proton transfer in 2-(2′-amino-3-pyridyl)-benzimidazole: effect of solvents. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2004.06.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Chowdhury PK, Halder M, Sanders L, Calhoun T, Anderson JL, Armstrong DW, Song X, Petrich JW. Dynamic Solvation in Room-Temperature Ionic Liquids†. J Phys Chem B 2004. [DOI: 10.1021/jp0376828] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Reactivity of the photo excited forms of Hypericin, Hypocrellin A, Hypocrellin B and methylated Hypericin towards molecular oxygen. J Photochem Photobiol A Chem 2004. [DOI: 10.1016/s1010-6030(03)00343-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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30
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Xu S, Zhang X, Chen S, Zhang M, Shen T. The Fluorescence Properties of Hypocrellin B and its Amino-substituted Derivative: Photoinduced Intramolecular Proton Transfer and Photoinduced Intramolecular Electron Transfer¶. Photochem Photobiol 2004; 80:112-4. [PMID: 15339225 DOI: 10.1562/2004-03-13-rn-113.1] [Citation(s) in RCA: 5] [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
We report on the emission spectra and emission quantum yields of a newly synthesized hypocrellin dye, 2-demethoxy-2,3-ethylenediamino hypocrellin B (EDAHB), and its parent HB in different solvents of varying polarity. Our results demonstrate that EDAHB is one of the few dyes that exhibit highly solvent polarity-dependent fluorescence in the useful region (680-730 nm). Therefore, it offers some applications in the biomedical field as a fluorescent probe molecule. The solvatochromic effect of EDAHB is proposed to be due to a distinct change in the dipole moment of the dye on excitation. A photoinduced intramolecular proton transfer and a photoinduced intramolecular electron transfer process are considered relevant for the fluorescence properties of HB and EDAHB, respectively.
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Affiliation(s)
- Shangjie Xu
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, People's Republic of China.
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31
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Xu S, Chen S, Zhang M, Shen T. Synthesis, characterization and photodynamic activity of phenmethylamino-demethoxy-hypocrellin B. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2003; 72:61-7. [PMID: 14644567 DOI: 10.1016/j.jphotobiol.2003.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two phenmethylamino hypocrellin B derivatives are novel photodynamic agents synthesized by a mild reaction between hypocrellin B and phenmethylamine. The red absorption of the photosensitizers is enlarged distinctly and the peri-hydroxylated perylenequinone structure of the parent HB is preserved. 9,10-diphenyl-anthracene (DPA) bleaching and electron paramagnetic resonance (EPR) spin trapping techniques were used to study the photodynamic activities of the phenmethylamino hypocrellin B derivatives in the presence of oxygen. Singlet oxygen (1O2) and superoxide anion radical (O2*-) generated in the process of illumination of the phenmethylamino hypocrellin B in aerobic solution were observed. The photodamage of PMAHBs to MGC803 cancer cells was investigated in vitro. The results in vitro reveal that the phenmethylamino hypocrellin B derivatives show a much less significant decrease in cytotoxicity than that of their parent HB. It exhibits higher selectivity of light-orientation, which can decrease the damage to normal tissues by irradiating the tumor tissues, and so increases the drug safety.
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Affiliation(s)
- Shangjie Xu
- Center for Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
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32
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Wang DP, Chen SG, Chen DZ. Theoretical study on the trihydroxy-anthraquinone tautomerism in the ground and excited states. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0166-1280(03)00529-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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33
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Xu S, Zhang X, Chen S, Zhang M, Shen T, Wang Z. Novel phototherapeutic agents: Investigation and progress of hypocrellin derivatives. ACTA ACUST UNITED AC 2003. [DOI: 10.1007/bf03184053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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34
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Halder M, Das K, Chowdhury PK, Kundu S, Hargrove MS, Petrich JW. A Comparative Femtosecond Coherence Study of the Unligated Monomeric Hemeproteins Myoglobin and Leghemoglobin. J Phys Chem B 2003. [DOI: 10.1021/jp034828u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Halder
- Department of Chemistry and Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - K. Das
- Department of Chemistry and Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - P. K. Chowdhury
- Department of Chemistry and Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - S. Kundu
- Department of Chemistry and Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - M. S. Hargrove
- Department of Chemistry and Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011
| | - J. W. Petrich
- Department of Chemistry and Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011
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35
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Xu S, Chen S, Zhang M, Shen T. First synthesis of methylated hypocrellin and its fluorescent excited state: a cautionary tale. J Org Chem 2003; 68:2048-50. [PMID: 12608836 DOI: 10.1021/jo026554x] [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: 11/29/2022]
Abstract
Methylated hypocrellins were obtained and characterized by satisfactory 1HNMR, UV-vis, IR, and mass data, and their absorption and fluorescence emission spectra were studied. A previous report of methylated hypocrellin (J. Phys. Chem. A 1999, 103, 7949) appears to be in error.
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Affiliation(s)
- Shangjie Xu
- Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
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36
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Xu S, Zhang X, Chen S, Zhang M, Shen T. EPR studies of the photodynamic properties of a novel potential photodynamic therapeutic agent: photogeneration of semiquinone radical anion and active oxygen species (O2˙−, OH˙, H2O2and1O2). Photochem Photobiol Sci 2003; 2:871-6. [PMID: 14521225 DOI: 10.1039/b303293k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyclohexylamino-substituted hypocrellin B (CHAHB) has been synthesized with the aim of improving the red absorption and specific affinity for malignant tumors over those of the parent compound. Irradiation of a deoxygenated DMSO solution of CHAHB generates a strong electron paramagnetic resonance (EPR) signal, which is assigned to the semiquinone radical anion of CHAHB with the aid of a series of experimental results. In the presence of oxygen, superoxide radical anions (O2*-) are generated via electron transfer from CHAHB*-, the precursor, to ground-state molecular oxygen. Hydroxyl radicals were detected by spin-trapping EPR when an oxygen-saturated aqueous solution containing CHAHB and DMPO was irradiated. Singlet oxygen (1O2) is produced via energy transfer from triplet CHAHB to ground-state oxygen molecules, with a sharply decreased quantum yield, i.e. 0.11. Furthermore, cell survival studies reveal CHAHB exhibits much higher photodynamic activities than its parent hypocrellins. The strongly enhanced photodynamic activities and sharply decreased quantum yield of 1O2 generation suggest that the type I (free radical) mechanism may play a significant role in CHAHB-PDT, rather than the type II (singlet oxygen) mechanism found in photofrin-PDT.
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Affiliation(s)
- Shangjie Xu
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China
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37
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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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38
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Liu J, Zhao YW, Zhao JQ, Xia AD, Jiang LJ, Wu S, Ma L, Dong YQ, Gu YH. Two-photon excitation studies of hypocrellins for photodynamic therapy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2002; 68:156-64. [PMID: 12468211 DOI: 10.1016/s1011-1344(02)00379-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The photophysical and photochemical properties of hypocrellins (HA and HB) are examined with two-photon excitations at 800 nm using femtosecond pulses from a Ti:sapphire laser. The two-photon excited fluorescence spectra of HA and HB are very similar to those obtained by one-photon excitation, which may indicate that the two-photon induced photodynamic processes of hypocrellins are similar to one-photon induced photodynamic processes. The two-photon excitation cross sections of HA and HB are measured at 800 nm as about 34.8 x 10(-50) cm(4) s/photon and 21.3 x 10(-50) cm(4) s/photon, respectively. The large two-photon cross sections of both HA and HB, suggest that the hypocrellins can be potential two-photon phototherapeutic agents. As an example for two-photon photodynamic therapy of hypocrellins, we also further examine the cell-damaging effects of HA upon two-photon illumination. Our preliminary results of cell viability test indicate hypocrellins can effectively damage the Hela cells under two-photon illumination.
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Affiliation(s)
- J Liu
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Science, Beijing 100080, China
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39
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Wen J, Chowdhury P, Wills NJ, Wannemuehler Y, Park J, Kesavan S, Carpenter S, Kraus GA, Petrich JW. Toward the molecular flashlight: preparation, properties, and photophysics of a hypericin-luciferin tethered molecule. Photochem Photobiol 2002; 76:153-7. [PMID: 12194210 DOI: 10.1562/0031-8655(2002)076<0153:ttmfpp>2.0.co;2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The synthesis of a molecule containing hypericin and luciferin moieties joined by a tether is reported. The light-induced (in vitro) antiviral activity as well as the photophysical properties of this new compound are measured and compared with those of the parent compounds, hypericin and pseudohypericin. This tethered molecule exhibits excited-state behavior that is very similar to that of its parent compounds and antiviral activity that is identical, within experimental error, to that of its more closely related parent compound, pseudohypericin. The implications for a photodynamic therapy that is independent of external light sources are discussed.
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Affiliation(s)
- Jin Wen
- Department of Chemistry, Iowa State University, Ames, IA 50011-3111, USA
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40
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Chen DZ, Wang DP, Zhang HY, Tang B. Theoretical study on the ground and excited state intramolecular proton transfer in perylenequinone. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(01)01471-3] [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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41
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Xu S, Chen S, Zhang M, Shen T, Zhao Y, Liu Z, Wu Y. Butylamino-demethoxy-hypocrellins and photodynamic therapy decreases human cancer in vitro and in vivo. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1537:222-32. [PMID: 11731224 DOI: 10.1016/s0925-4439(01)00074-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
2-Butylamino-2-demethoxy-hypocrellin A (BAHA) and B (BAHB) are new photosensitizers synthesized by a mild reaction of hypocrellins and butylamine. In BAHA and BAHB, the peri-hydroxylated perylenequinone structure of the parent hypocrellins is preserved and the red absorption is enhanced distinctly. Electron paramagnetic resonance spin trapping measurements and 9,10-diphenylanthracene bleaching studies were used to investigate the photodynamic action of BAHA and BAHB in the presence of oxygen. Singlet oxygen (1O2) and superoxide anion radical (O2(*-)) produced by illuminating BAHA and BAHB in aerobic solution have been observed. Compared with hypocrellin A and B, BAHA and BAHB primarily remained able to generate 1O2 and enhanced distinctly the O2(*-)-generating abilities. The photodynamic action of BAHA and BAHB in the therapy of cancer was investigated in vitro and in vivo. Both in vitro and in vivo results revealed a significant decrease in cancer cell growth. Laser or dye alone had no effect, indicating that intratumor BAHA and laser therapy may prove useful in unresectable cancer.
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Affiliation(s)
- S Xu
- Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, PR China
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42
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Xu S, Chen S, Zhang M, Shen T. A novel method for the preparation of amino-substituted hypocrellin B. Bioorg Med Chem Lett 2001; 11:2045-7. [PMID: 11454477 DOI: 10.1016/s0960-894x(01)00360-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A series of amino-substituted hypocrellins derived from hypocrellin B (HB) were synthesized by a novel mild method, in which the peri-hydroxylated perylenequinone structure of hypocrellin was preserved by the reaction of HB with an amine. The red absorption of the resulting products was significantly enhanced relative to the parent hypocrellins, which will significantly improve its photodynamic therapy effectiveness.
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Affiliation(s)
- S Xu
- Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, 100080, Beijing, China
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43
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Xu S, Tian C, Chen S, Zhang M, Shen T. Photobleaching of hypocrellin B and its butylamino-substituted derivative in solutions. Photochem Photobiol 2001; 74:184-90. [PMID: 11547552 DOI: 10.1562/0031-8655(2001)074<0184:pohbai>2.0.co;2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The photobleaching of hypocrellin B (HB) and its derivative butylamino-substituted hypocrellin B (BAHB), both of which are potent sensitizers for photodynamic therapy (PDT), were investigated by studies of absorption spectra and quenching experiments and by the determination of photoproducts. Control experiments indicated that the sensitizer, oxygen and light were essential for the photobleaching of HB and BAHB, which suggested that it was a photodynamic process, e.g. the photobleaching processes of both HB and BAHB were mainly self-sensitized photooxidations. The illumination of HB with visible light in oxygenated nonpolar solvents generated singlet oxygen efficiently [phi(1O2) = 0.76] which in turn attacked the sensitizer HB with the subsequent formation of an endoperoxide product. The endoperoxide of HB is unstable at room temperature and undergoes loss of singlet oxygen with regeneration of the parent HB. The singlet oxygen released from the endoperoxide of HB was detected with chemical trapping experiments. The quenching experiments indicated that in increasingly polar solvents the superoxide anion mechanism (type I) as well as the singlet oxygen mechanism (type II) contributed to the photobleaching of HB. The introduction of the electron-donating butylamino group not only enhanced the yield of the superoxide anion generation but also altered the position of attack in the BAHB molecule by the activated oxygen species. No endoperoxide product was observed, and no singlet oxygen released from the photobleaching process of BAHB was detected. The photobleaching process of BAHB was more complex. Both the singlet oxygen and superoxide anion mechanism played important roles in the photobleaching of BAHB in all organic solvent used here, even in aerobic nonpolar solvents such as CHCl3.
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Affiliation(s)
- S Xu
- Center of Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, People's Republic of China
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44
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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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45
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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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46
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Weitman H, Roslaniec M, Frimer AA, Afri M, Freeman D, Mazur Y, Ehrenberg B. Solvatochromic effects in the electronic absorption and nuclear magnetic resonance spectra of hypericin in organic solvents and in lipid bilayers. Photochem Photobiol 2001; 73:110-8. [PMID: 11272723 DOI: 10.1562/0031-8655(2001)073<0110:seitea>2.0.co;2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The natural product hypericin was tested in recent years as a biological photosensitizer with a potential for viral and cellular photodamage. We thus studied extensively its spectroscopy and membrane partitioning. Absorption, fluorescence excitation and emission spectra of the sodium salt (HyNa) were measured in 36 protic and aprotic, polar and apolar, solvents. Electronic transition bands as well as vibrational progressions were identified. Aggregation in some nonpolar solvents and protonation in organic acids were demonstrated. Modeling solvatochromism was done by Lippert equation, by the ET(30) parameter and by the Taft multiparameter approach. In all cases, separation into protic and aprotic solvents gave much better fits to the models. 13C chemical shift data could also be correlated with solvent polarity. They correlated best with Lippert's delta f polarity measure, but tended to fall into two distinct solvent groups--each along different lines--corresponding to protic and aprotic media, respectively. This interesting phenomenon suggests that in the case of the charged and slightly water soluble HyNa, two mechanisms of solvation are involved, each resulting in its own line equation. In aprotic media, dipole-dipole interaction is the predominant solvation mechanism. In protic solvents, the most effective means of solvation is likely to be hydrogen bonding. When intercalated into the liposomal phospholipid bilayer, HyNa is oriented at an angle to the interface, thus experiencing a gradient of solvent polarities: a highly polar environment (similar to methanol) for C-2/5, suggesting that they lie not far from the interface; a moderately polar environment (similar to that of n-propanol) for C-6a/14a, which are somewhat deeper within the bilayer; and a more lipophilic environment (akin to n-hexanol) for C-10/11. The fluorescence excitation peak in liposomes also correlates with an aprotic medium of relatively high polarity, as might be excepted from a molecule in a shallow position in the bilayer.
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Affiliation(s)
- H Weitman
- Department of Physics, Bar Ilan University, Ramat Gan 52900, Israel
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Abstract
The excited-state intramolecular H-atom transfer of hypericin (Hyp) was investigated as a function of pH in monodispersed reverse micelles formed by sodium bis(2-ethylhexyl)sulfosuccinate/heptane/water and in complexes with Tb3+ under conditions in which one of the two carbonyl groups of Hyp is incapable of accepting a hydrogen atom. The results of pump-probe transient absorption experiments provide no evidence for a concerted H-atom transfer mechanism.
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Affiliation(s)
- J Park
- Department of Chemistry, Iowa State University, Ames 50011, USA
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48
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Santra S, Krishnamoorthy G, Dogra SK. Excited-state intramolecular proton transfer in the anionic species of 2-(2′-acetamidophenyl)benzimidazole in aqueous medium. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00807-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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49
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Roslaniec M, Weitman H, Freeman D, Mazur Y, Ehrenberg B. Liposome binding constants and singlet oxygen quantum yields of hypericin, tetrahydroxy helianthrone and their derivatives: studies in organic solutions and in liposomes. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2000; 57:149-58. [PMID: 11154081 DOI: 10.1016/s1011-1344(00)00090-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The spectroscopy and photophysics of several hypericin and helianthrone derivatives were studied in methanol and when bound to liposomes. The singlet oxygen quantum yields (phi(delta)) were measured indirectly relative to Rose Bengal and hematoporphyrin IX, employing 9,10-dimethylanthracene as a singlet oxygen trap. Hypericin was found to have a phi(delta) of 0.39+/-0.01 in methanol, and 0.35+/-0.05 in lecithin vesicles, in agreement with literature values. A heavy atom effect was evident upon bromination, resulting in phi(delta) for tetrabromohypericin of 0.72+/-0.02, presumably due to enhanced intersystem crossing. Elimination of the anionic hydroxyls by methylation also enhanced phi(delta) to 0.81+/-0.01. Conversely, addition of anionic sulfate groups drastically reduced phi(delta) resulting in phi(delta)'s of 0.12+/-0.01, 0.052+/-0.003 and 0.40+/-0.01 for hypericin disulfonate, hypericin tetrasulfonate and hexamethyl hypericin tetrasulfonate, respectively. The non-sulfonated helianthrones exhibited low phi(delta)'s in solution. The liposome binding constants, Kb, were measured using a spectroscopic assay. Except for hexamethyl hypericin, all non-sulfonated compounds bound well with Kb's ranging from 15.5+/-0.1 to 48.7+/-3.9 (mg/ml)(-1). None of the tetrasulfonated compounds bound, however the hypericin disulfonate had a Kb of 4.1+/-0.2 (mg/ml)(-1). The phi(delta)'s of the compounds capable of binding were measured and, in the case of the hypericin derivatives, were found not to vary dramatically from those in the free state. Liposome-bound helianthrone and dimethyl tetrahydroxy helianthrone both exhibited high phi(delta)'s, i.e. >0.5. The variations in binding constant and sensitization efficiencies are explained in conjunction with the molecular structure. The relevance of the above data to photodynamic therapy is briefly discussed.
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Affiliation(s)
- M Roslaniec
- Department of Physics, Bar Ilan University, Ramat Gan, Israel
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50
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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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