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Joyner JC, Cowan JA. Target-directed catalytic metallodrugs. Braz J Med Biol Res 2013; 46:465-85. [PMID: 23828584 PMCID: PMC3854446 DOI: 10.1590/1414-431x20133086] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 03/11/2013] [Indexed: 01/08/2023] Open
Abstract
Most drugs function by binding reversibly to specific biological targets, and therapeutic effects generally require saturation of these targets. One means of decreasing required drug concentrations is incorporation of reactive metal centers that elicit irreversible modification of targets. A common approach has been the design of artificial proteases/nucleases containing metal centers capable of hydrolyzing targeted proteins or nucleic acids. However, these hydrolytic catalysts typically provide relatively low rate constants for target inactivation. Recently, various catalysts were synthesized that use oxidative mechanisms to selectively cleave/inactivate therapeutic targets, including HIV RRE RNA or angiotensin converting enzyme (ACE). These oxidative mechanisms, which typically involve reactive oxygen species (ROS), provide access to comparatively high rate constants for target inactivation. Target-binding affinity, co-reactant selectivity, reduction potential, coordination unsaturation, ROS products (metal-associated vs metal-dissociated; hydroxyl vs superoxide), and multiple-turnover redox chemistry were studied for each catalyst, and these parameters were related to the efficiency, selectivity, and mechanism(s) of inactivation/cleavage of the corresponding target for each catalyst. Important factors for future oxidative catalyst development are 1) positioning of catalyst reduction potential and redox reactivity to match the physiological environment of use, 2) maintenance of catalyst stability by use of chelates with either high denticity or other means of stabilization, such as the square planar geometric stabilization of Ni- and Cu-ATCUN complexes, 3) optimal rate of inactivation of targets relative to the rate of generation of diffusible ROS, 4) targeting and linker domains that afford better control of catalyst orientation, and 5) general bio-availability and drug delivery requirements.
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Affiliation(s)
- J C Joyner
- Evans Laboratory of Chemistry, Ohio State University, Columbus, OH 43210, USA.
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Michail K, Siraki AG. Post-trapping derivatization of radical-derived EPR-silent adducts: application to free radical detection by HPLC/UV in chemical, biochemical, and biological systems and comparison with EPR spectroscopy. Anal Chem 2012; 84:6739-46. [PMID: 22724922 DOI: 10.1021/ac301142c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Free radicals are conventionally detected by electron paramagnetic resonance (EPR) spectroscopy after being trapped as spin adducts. Albeit this technique has demonstrated utmost efficacy in studying free radicals, its application to biological settings is intrinsically hampered by the inevitable bioreduction of radical-derived paramagnetic adducts. Herein, we describe a reliable technique to detect and quantify free radical metabolites, wherein reduced alkyl- and phenyl-5,5-dimethyl-1-pyrroline N-oxide (DMPO) adducts are converted into ultrastable N-naphthoate esters. To mimic the ubiquitous in vivo microenvironment, bioreductants, exogenous thiols, and sodium borohydride were studied. Nitroxyl reduction was confirmed using EPR and triphenyltetrazolium chloride. The formation of the N-naphthoyloxy derivatives was established by liquid chromatography/mass spectrometry (LC/MS). The derivatives were chromatographed using a binary eluent. HPLC and internal standards were synthesized using Grignard addition. The labeled DMPO adduct is (1) fluorescent, (2) stable as opposed to nitroxyl radical adducts, (3) biologically relevant, and (4) excellently chromatographed. Applications encompassed chemical, biochemical, and biological model systems generating C-centered radicals. Different levels of phenyl radicals produced in situ from whole blood were successfully determined. The method is readily applicable to the detection of hydroxyl radical. Analogously, DMPO, the spin trap, could be detected with extreme sensitivity suitable for in vivo applications. The developed method proved to be a viable alternative to EPR, where for the first time the reductive loss of paramagnetic signals of DMPO-trapped free radicals is transformed into fluorescence emission. We believe the proposed methodology could represent a valuable tool to probe free radical metabolites in vivo using DMPO, the least toxic spin trap.
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Affiliation(s)
- Karim Michail
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.
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Joyner JC, Reichfield J, Cowan JA. Factors influencing the DNA nuclease activity of iron, cobalt, nickel, and copper chelates. J Am Chem Soc 2011; 133:15613-26. [PMID: 21815680 DOI: 10.1021/ja2052599] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A library of complexes that included iron, cobalt, nickel, and copper chelates of cyclam, cyclen, DOTA, DTPA, EDTA, tripeptide GGH, tetrapeptide KGHK, NTA, and TACN was evaluated for DNA nuclease activity, ascorbate consumption, superoxide and hydroxyl radical generation, and reduction potential under physiologically relevant conditions. Plasmid DNA cleavage rates demonstrated by combinations of each complex and biological co-reactants were quantified by gel electrophoresis, yielding second-order rate constants for DNA(supercoiled) to DNA(nicked) conversion up to 2.5 × 10(6) M(-1) min(-1), and for DNA(nicked) to DNA(linear) up to 7 × 10(5) M(-1) min(-1). Relative rates of radical generation and characterization of radical species were determined by reaction with the fluorescent radical probes TEMPO-9-AC and rhodamine B. Ascorbate turnover rate constants ranging from 3 × 10(-4) to 0.13 min(-1) were determined, although many complexes demonstrated no measurable activity. Inhibition and Freifelder-Trumbo analysis of DNA cleavage supported concerted cleavage of dsDNA by a metal-associated reactive oxygen species (ROS) in the case of Cu(2+)(aq), Cu-KGHK, Co-KGHK, and Cu-NTA and stepwise cleavage for Fe(2+)(aq), Cu-cyclam, Cu-cyclen, Co-cyclen, Cu-EDTA, Ni-EDTA, Co-EDTA, Cu-GGH, and Co-NTA. Reduction potentials varied over the range from -362 to +1111 mV versus NHE, and complexes demonstrated optimal catalytic activity in the range of the physiological redox co-reactants ascorbate and peroxide (-66 to +380 mV).
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Affiliation(s)
- Jeff C Joyner
- Evans Laboratory of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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Wang J, Dang V, Zhao W, Lu D, Rivera BK, Villamena FA, Wang PG, Kuppusamy P. Perchlorotrityl radical-fluorophore conjugates as dual fluorescence and EPR probes for superoxide radical anion. Bioorg Med Chem 2009; 18:922-9. [PMID: 19963389 DOI: 10.1016/j.bmc.2009.11.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Revised: 11/11/2009] [Accepted: 11/14/2009] [Indexed: 11/24/2022]
Abstract
Perchlorotrityl radicals, mono-substituted with a fluorophore using an amide linker of varying chain length, were synthesized and characterized. Electron paramagnetic resonance (EPR) spectroscopic study indicated free-electron coupling with the aromatic hydrogen nuclei and long-range coupling with the methylene hydrogens of the linker group. Reactivity of the fluorophore-conjugated trityls with superoxide radical anion showed quenching of EPR signal and enhancement of fluorescence emission spectrum. This work presents the first example of a perchlorotrityl-fluorophore conjugate that can potentially be employed as a dual probe for the detection of superoxide under oxidative stress-mediated conditions in biological systems.
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Affiliation(s)
- Jinhua Wang
- Davis Heart and Lung Research Institute, Department of Chemistry, The Ohio State University, Columbus, OH 43210, USA
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Bueno C, Mikelsons L, Maretti L, Scaiano JC, Aspée A. Photophysical Properties of the Prefluorescent Nitroxide Probes QT and C343T. Photochem Photobiol 2008; 84:1535-42. [DOI: 10.1111/j.1751-1097.2008.00381.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Degradation of lyophilized lipid/DNA complexes during storage: The role of lipid and reactive oxygen species. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:2119-26. [DOI: 10.1016/j.bbamem.2008.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 04/03/2008] [Accepted: 04/03/2008] [Indexed: 11/18/2022]
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Soh N, Ariyoshi T, Fukaminato T, Nakajima H, Nakano K, Imato T. Swallow-tailed perylene derivative: a new tool for fluorescent imaging of lipid hydroperoxides. Org Biomol Chem 2007; 5:3762-8. [PMID: 18004455 DOI: 10.1039/b713223a] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A swallow-tailed perylene derivative including a triphenylphosphine moiety was synthesized and applied to the detection and the live-cell imaging of lipid hydroperoxides. The novel probe, named Spy-LHP, reacted rapidly and quantitatively with lipid hydroperoxides to form the corresponding oxide, Spy-LHPOx, which emits extremely strong fluorescence (Phi approximately 1) in the visible range (lambda(em) = 535 nm, 574 nm). Spy-LHP was highly selective for lipid hydroperoxides, and the addition of other reactive oxygen species (ROS) including hydrogen peroxides, hydroxyl radical, superoxide anion, nitric oxide, peroxynitrite, and alkylperoxyl radical, caused no significant increase in the fluorescence intensity. The probe exhibited good localization to cellular membranes and was successfully applied to the confocal laser scanning microscopy (CLSM) imaging of lipid hydroperoxides in live J774A.1 cells, in which lipid peroxidation was proceeded by the stimulation of 2,2-azobis(2-amidinopropane)dihydrochloride (AAPH). These findings establish Spy-LHP as a promising new tool for investigating the physiology of lipid hydroperoxides.
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Affiliation(s)
- Nobuaki Soh
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744, Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.
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Soh N. Recent advances in fluorescent probes for the detection of reactive oxygen species. Anal Bioanal Chem 2006; 386:532-43. [PMID: 16609844 DOI: 10.1007/s00216-006-0366-9] [Citation(s) in RCA: 237] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Accepted: 02/15/2006] [Indexed: 10/24/2022]
Abstract
Reactive oxygen species (ROS) have captured the interest of many researchers in the chemical, biological, and medical fields since they are thought to be associated with various pathological conditions. Fluorescent probes for the detection of ROS are promising tools with which to enhance our understanding of the physiological roles of ROS, because they provide spatial and temporal information about target biomolecules in in vivo cellular systems. ROS probes, designed to detect specific ROS with a high selectivity, would be desirable, since it is now becoming clear that each ROS has its own unique physiological activity. However, dihydro-compounds such as 2',7'-dichlorodihydrofluorescein (DCFH), which have traditionally been used for detecting ROS, tend to react with a wide variety of ROS and are not completely photostable. Some attractive fluorescent probes that exhibit a high degree of selectivity toward specific ROS have recently been reported, and these selective probes are expected to have great potential for elucidating unknown physiological mechanisms associated with their target ROS. This review focuses on the design, detection mechanism, and performance of fluorescent probes for the detection of singlet oxygen ((1)O(2)), hydrogen peroxide (H(2)O(2)), hydroxyl radicals ((.)OH), or superoxide anion (O(2) (-.)), a field in which remarkable progress has been achieved in the last few years.
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Affiliation(s)
- Nobuaki Soh
- Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744, Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
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Hideg E, Kálai T, Kós PB, Asada K, Hideg K. Singlet Oxygen in Plants—Its Significance and Possible Detection with Double (Fluorescent and Spin) Indicator Reagents. Photochem Photobiol 2006; 82:1211-8. [PMID: 16608386 DOI: 10.1562/2006-02-06-ra-797] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Direct detection of reactive oxygen species (ROS), especially singlet oxygen, in plants under stress conditions is of special importance, not only to identify primary events of oxidative damage, but also in studies exploring the potential role of ROS as signal molecules. Due to short life-times and diffusion distances of ROS, these tasks require highly reactive and selective indicator reagents, localized at the presumed site of production. In the present study, we compared four double sensors: ROS indicator reagents in which partial fluorescence quenching of a dansyl moiety occurs as a result of nitroxide radical formation from a sterically hindered amine constituent. Our experiments support the idea that shorter donor-acceptor distances within these molecules result in higher reactivity to ROS. The presence of a diethylaminoethyl side chain resulted in better selectivity to singlet oxygen: reagents lacking such substituent had an additional reactivity to superoxide anions, probably as a result of the formation of zwitterionic structures. Fluorescence localization studies of the indicator reagents in tobacco leaves and in Chlamydomonas cells show promising perspectives of their applications to plant stress studies.
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Affiliation(s)
- Eva Hideg
- Institute of Plant Biology, Biological Research Center, H-6701 Szeged, PO Box 521, Hungary.
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Chapter 2 Primary processes in photosensitization mechanisms. COMPREHENSIVE SERIES IN PHOTOSCIENCES 2001. [DOI: 10.1016/s1568-461x(01)80106-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Bätz M, Korth HG, Meineke P, Sustmann R. Fluorescence detection of nitric oxide based on cheletropic spin traps. Methods Enzymol 1999; 301:532-9. [PMID: 9919601 DOI: 10.1016/s0076-6879(99)01116-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Affiliation(s)
- M Bätz
- Institut für Organische Chemie, Universität Essen, Germany
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Brunet J, Farine JC, Garay RP, Hannaert P. In vitro antioxidant properties of calcium dobesilate. Fundam Clin Pharmacol 1998; 12:205-12. [PMID: 9565776 DOI: 10.1111/j.1472-8206.1998.tb00943.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Calcium dobesilate, a vascular protective agent, was tested in vitro for its scavenging action against oxygen free radicals. Calcium dobesilate was as potent as rutin to scavenge hydroxyl radicals (IC50 = 1.1 vs 0.7 microM, respectively). It was also able to scavenge superoxide radicals, but with 23 times less potency than rutin (IC50 = 682 vs 30 microM, respectively). Calcium dobesilate significantly reduced platelet activating factor (PAF)-induced chemiluminescence in human PMN cells and lipid peroxidation by oxygen free radicals in human erythrocyte membranes, although these actions required calcium dobesilate concentrations > or = 50 microM. Finally, in cultured bovine aortic endothelial cells, magnesium dobesilate reduced the increase in cytosolic free calcium induced by hydrogen peroxide and inhibited phenazine methosulfate-induced cell potassium loss. In conclusion, calcium dobesilate was effective in scavenging hydroxyl radicals in vitro, at therapeutically relevant concentrations. Conversely, higher concentrations of the compound were required to scavenge superoxide radicals or to protect the cells against the deleterious effects of intracellular reactive oxygen species. Further studies in vivo are required to determine if these antioxidant properties of calcium dobesilate can play a role in its vascular protective mechanisms.
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Affiliation(s)
- J Brunet
- INSERM U400, Faculté de Médecine, Créteil, France
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Kálai T, Hideg E, Vass I, Hideg K. Double (fluorescent and spin) sensors for detection of reactive oxygen species in the thylakoid membrane. Free Radic Biol Med 1998; 24:649-52. [PMID: 9559877 DOI: 10.1016/s0891-5849(97)00339-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A series of dansylated sterically hindered amines designed to trapping reactive oxygen species, were synthesized. Compounds were tested in isolated thylakoid membranes subjected to photoinhibition by excess photosynthetically active radiation (400-700 nm). DanePy showed good selectivity for singlet oxygen and the formation of nitroxide was detected by appearance of ESR signal and quenching fluorescence.
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Affiliation(s)
- T Kálai
- Institute of Organic and Medicinal Chemistry, University of Pécs, Hungary
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Bätz M, Korth HG, Sustmann R. Eine neuartige Methode zum Nachweis von Stickstoffmonoxid (NO) durch Bildung fluoreszierender Produkte auf der Basis cheletroper Spinfänger. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971091329] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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