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Zhou Y, Phelps GA, Mangrum MM, McLeish J, Phillips EK, Lou J, Ancajas CF, Rybak JM, Oelkers PM, Lee RE, Best MD, Reynolds TB. The small molecule CBR-5884 inhibits the Candida albicans phosphatidylserine synthase. mBio 2024; 15:e0063324. [PMID: 38587428 PMCID: PMC11077991 DOI: 10.1128/mbio.00633-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 03/12/2024] [Indexed: 04/09/2024] Open
Abstract
Systemic infections by Candida spp. are associated with high mortality rates, partly due to limitations in current antifungals, highlighting the need for novel drugs and drug targets. The fungal phosphatidylserine synthase, Cho1, from Candida albicans is a logical antifungal drug target due to its importance in virulence, absence in the host, and conservation among fungal pathogens. Inhibitors of Cho1 could serve as lead compounds for drug development, so we developed a target-based screen for inhibitors of purified Cho1. This enzyme condenses serine and cytidyldiphosphate-diacylglycerol (CDP-DAG) into phosphatidylserine (PS) and releases cytidylmonophosphate (CMP). Accordingly, we developed an in vitro nucleotidase-coupled malachite-green-based high throughput assay for purified C. albicans Cho1 that monitors CMP production as a proxy for PS synthesis. Over 7,300 molecules curated from repurposing chemical libraries were interrogated in primary and dose-responsivity assays using this platform. The screen had a promising average Z' score of ~0.8, and seven compounds were identified that inhibit Cho1. Three of these, ebselen, LOC14, and CBR-5884, exhibited antifungal effects against C. albicans cells, with fungicidal inhibition by ebselen and fungistatic inhibition by LOC14 and CBR-5884. Only CBR-5884 showed evidence of disrupting in vivo Cho1 function by inducing phenotypes consistent with the cho1∆∆ mutant, including a reduction of cellular PS levels. Kinetics curves and computational docking indicate that CBR-5884 competes with serine for binding to Cho1 with a Ki of 1,550 ± 245.6 nM. Thus, this compound has the potential for development into an antifungal compound. IMPORTANCE Fungal phosphatidylserine synthase (Cho1) is a logical antifungal target due to its crucial role in the virulence and viability of various fungal pathogens, and since it is absent in humans, drugs targeted at Cho1 are less likely to cause toxicity in patients. Using fungal Cho1 as a model, there have been two unsuccessful attempts to discover inhibitors for Cho1 homologs in whole-cell screens prior to this study. The compounds identified in these attempts do not act directly on the protein, resulting in the absence of known Cho1 inhibitors. The significance of our research is that we developed a high-throughput target-based assay and identified the first Cho1 inhibitor, CBR-5884, which acts both on the purified protein and its function in the cell. This molecule acts as a competitive inhibitor with a Ki value of 1,550 ± 245.6 nM and, thus, has the potential for development into a new class of antifungals targeting PS synthase.
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Affiliation(s)
- Yue Zhou
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Gregory A. Phelps
- Department of Chemical Biology & Therapeutics, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
- Graduate School of Biomedical Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Mikayla M. Mangrum
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Jemma McLeish
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Elise K. Phillips
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Jinchao Lou
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, USA
| | | | - Jeffrey M. Rybak
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Peter M. Oelkers
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, Michigan, USA
| | - Richard E. Lee
- Department of Chemical Biology & Therapeutics, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Michael D. Best
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, USA
| | - Todd B. Reynolds
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
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2
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Robertson RP. Antioxidants for Early Treatment of Type 2 Diabetes in Rodents and Humans: Lost in Translation? Diabetes 2024; 73:653-658. [PMID: 38387049 PMCID: PMC11043055 DOI: 10.2337/db23-0901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/13/2024] [Indexed: 02/24/2024]
Abstract
Reactive oxygen species (ROS) are formed by virtually all tissues. In normal concentrations they facilitate many physiologic activities, but in excess they cause oxidative stress and tissue damage. Local antioxidant enzyme synthesis in cells is regulated by the cytoplasmic KEAP-1/Nrf2 complex, which is stimulated by ROS, to release Nrf2 for entry into the nucleus, where it upregulates antioxidant gene expression. Major antioxidant enzymes include glutathione peroxidase (GPx), catalase (CAT), superoxide dismutases (SOD), hemoxygenases (HO), and peroxiredoxins (Prdx). Notably, the pancreatic islet β-cell does not express GPx or CAT, which puts it at greater risk for ROS damage caused by postprandial hyperglycemia. Experimentally, overexpression of GPx in β-cell lines and isolated islets, as well as in vivo studies using genetic models of type 2 diabetes (T2D), has demonstrated enhanced protection against hyperglycemia and oxidative stress. Oral treatment of diabetic rodents with ebselen, a GPx mimetic that is approved for human clinical use, reproduced these findings. Prdx detoxify hydrogen peroxide and reduce lipid peroxides. This suggests that pharmacologic development of more potent, β-cell-specific antioxidants could be valuable as a treatment for oxidative stress due to postprandial hyperglycemia in early T2D in humans. ARTICLE HIGHLIGHTS
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Affiliation(s)
- R. Paul Robertson
- Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, WA
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3
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Ali F, Alom S, Ali SR, Kondoli B, Sadhu P, Borah C, Kakoti BB, Ghosh SK, Shakya A, Ahmed AB, Singh UP, Bhat HR. Ebselen: A Review on its Synthesis, Derivatives, Anticancer Efficacy and Utility in Combating SARS-COV-2. Mini Rev Med Chem 2024; 24:1203-1225. [PMID: 37711004 DOI: 10.2174/1389557523666230914103339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/26/2023] [Accepted: 06/16/2023] [Indexed: 09/16/2023]
Abstract
Ebselen is a selenoorganic chiral compound with antioxidant properties comparable to glutathione peroxidase. It is also known as 2-phenyl-1,2-benzisoselenazol-3(2H)-one. In studies examining its numerous pharmacological activities, including antioxidant, anticancer, antiviral, and anti- Alzheimer's, ebselen has demonstrated promising results. This review's primary objective was to emphasize the numerous synthesis pathways of ebselen and their efficacy in fighting cancer. The data were collected from multiple sources, including Scopus, PubMed, Google Scholar, Web of Science, and Publons. The starting reagents for the synthesis of ebselen are 2-aminobenzoic acid and N-phenyl benzamide. It was discovered that ebselen has the ability to initiate apoptosis in malignant cells and prevent the formation of new cancer cells by scavenging free radicals. In addition, ebselen increases tumor cell susceptibility to apoptosis by inhibiting TNF-α mediated NF-kB activation. Ebselen can inhibit both doxorubicin and daunorubicin-induced cardiotoxicity. Allopurinol and ebselen administered orally can be used to suppress renal ototoxicity and nephrotoxicity. Due to excessive administration, diclofenac can induce malignancy of the gastrointestinal tract, which ebselen can effectively suppress. Recent research has demonstrated ebselen to inhibit viral function by binding to cysteinecontaining catalytic domains of various viral proteases. It was discovered that ebselen could inhibit the catalytic dyad function of Mpro by forming an irreversible covalent bond between Se and Cys145, thereby altering protease function and inhibiting SARS-CoV-2. Ebselen may also inhibit the activation of endosomal NADPH oxidase of vascular endothelial cells, which is believed to be required for thrombotic complications in COVID-19. In this review, we have included various studies conducted on the anticancer effect of ebselen as well as its inhibition of SARS-CoV-2.
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Affiliation(s)
- Farak Ali
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam, 786004, India
- Girijananda Chowdhury Institute of Pharmaceutical Science, Tezpur Medical College and Hospital, Tezpur, Sonitpur Assam, 784501,India
| | - Shahnaz Alom
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam, 786004, India
- Girijananda Chowdhury Institute of Pharmaceutical Science, Tezpur Medical College and Hospital, Tezpur, Sonitpur Assam, 784501,India
| | - Sheikh Rezzak Ali
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam, 786004, India
| | - Biswanarayan Kondoli
- Department of Pharmacy, Tripura University, Suryamani Nagar, Agartala, Tripura 799022, India
| | - Prativa Sadhu
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam, 786004, India
| | - Chinmoyee Borah
- Girijananda Chowdhury Institute of Pharmaceutical Science, Guwahati, Kamrup, Assam, 781017, India
| | - Bibhuti Bushan Kakoti
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam, 786004, India
| | - Surajit Kumar Ghosh
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam, 786004, India
| | - Anshul Shakya
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam, 786004, India
| | - Abdul Baquee Ahmed
- Girijananda Chowdhury Institute of Pharmaceutical Science,Tezpur Medical College and Hospital, Tezpur, Sonitpur-784501, Assam, India
| | - Udaya Pratap Singh
- Drug Design & Discovery Laboratory, Department of Pharmaceutical Sciences, Sam Higginbottom University of Agriculture, Technology & Sciences, Allahabad, Uttar Pradesh, 211007, India
| | - Hans Raj Bhat
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam, 786004, India
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de Oliveira LFG, Britto-Júnior J, Lima AT, Moraes MO, Moraes MEA, de Souza VB, Schenka AA, Monica FZ, De Nucci G. Release of 6-nitrodopamine from human popliteal artery and vein. Life Sci 2023:121801. [PMID: 37244364 DOI: 10.1016/j.lfs.2023.121801] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/13/2023] [Accepted: 05/22/2023] [Indexed: 05/29/2023]
Abstract
6-Nitrodopamine (6-ND) is a novel catecholamine that is released from human umbilical cord vessels, and it causes vascular relaxation by acting as a dopamine D2-receptor antagonist. Here it was investigated whether human peripheral vessels obtained from patients who have undergone surgery for leg amputation release 6-ND, and its action in these tissues. Popliteal artery and vein strips present basal release of 6-ND, as measure by liquid chromatography coupled to tandem mass spectrometry. The release was significantly reduced when the tissues were pre-treated with the nitric oxide synthase inhibitor L-NAME (100 μM), or when the endothelium was mechanically removed. In U-46619 (3 nM) pre-contracted rings, 6-ND induced concentration-dependent relaxations (pEC50 8.18 ± 0.05 and 8.40 ± 0.08, in artery and vein rings, respectively). The concentration-dependent relaxations induced by 6-ND were unaffected in tissues pre-treated with L-NAME, but significantly reduced in tissues where the endothelium has been mechanically removed. In U-46619 (3 nM) pre-contracted rings, the selective dopamine D2 receptor antagonist L-741,626 also caused concentration-dependent relaxations (pEC50 8.92 ± 0.22 and 8.79 ± 0.19, in artery and vein rings, respectively). The concentration-dependent relaxations induced by L-741,626 were unaffected in tissues pre-treated with L-NAME, but significantly reduced in tissues where the endothelium has been mechanically removed. This is the first demonstration that 6-nitrodopamine is released from human peripheral artery and vein rings. The results also indicate that endothelium-derived dopamine is a major contractile agent in the popliteal artery and vein, and that selective dopamine D2-receptor antagonists such as 6-ND, may have therapeutic potential in the treatment of human peripheral vascular diseases.
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Affiliation(s)
| | - José Britto-Júnior
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
| | - Antonio Tiago Lima
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
| | - Manoel Odorico Moraes
- Clinical Pharmacology Unit, Drug Research and Development Center, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Maria Elisabete A Moraes
- Clinical Pharmacology Unit, Drug Research and Development Center, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Valéria Barbosa de Souza
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
| | - André Almeida Schenka
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
| | - Fabiola Z Monica
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
| | - Gilberto De Nucci
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil; Clinical Pharmacology Unit, Drug Research and Development Center, Federal University of Ceará, Fortaleza, Ceará, Brazil; Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, São Paulo, Brazil; Deparment of Pharmacology, Faculty of Medicine, Metropolitan University of Santos, Santos, São Paulo, Brazil
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5
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Nrf2 and Antioxidant Response in Animal Models of Type 2 Diabetes. Int J Mol Sci 2023; 24:ijms24043082. [PMID: 36834496 PMCID: PMC9961396 DOI: 10.3390/ijms24043082] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/18/2023] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
This perspective examines the proposition that chronically elevated blood glucose levels caused by type 2 diabetes (T2D) harm body tissues by locally generating reactive oxygen species (ROS). A feed-forward scenario is described in which the initial onset of defective beta cell function T2D becomes sustained and causes chronic elevations in blood glucose, which flood metabolic pathways throughout the body, giving rise to abnormally high local levels of ROS. Most cells can defend themselves via a full complement of antioxidant enzymes that are activated by ROS. However, the beta cell itself does not contain catalase or glutathione peroxidases and thereby runs a greater risk of ROS-induced damage. In this review, previously published experiments are revisited to examine the concept that chronic hyperglycemia can lead to oxidative stress in the beta cell, how this relates to the absence of beta cell glutathione peroxidase (GPx) activity, and whether this deficiency might be ameliorated by genetic enrichment of beta cell GPx and by oral antioxidants, including ebselen, a GPx mimetic.
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6
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Bayır H, Anthonymuthu TS, Tyurina YY, Patel SJ, Amoscato AA, Lamade AM, Yang Q, Vladimirov GK, Philpott CC, Kagan VE. Achieving Life through Death: Redox Biology of Lipid Peroxidation in Ferroptosis. Cell Chem Biol 2020; 27:387-408. [PMID: 32275865 DOI: 10.1016/j.chembiol.2020.03.014] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 03/02/2020] [Accepted: 03/17/2020] [Indexed: 12/11/2022]
Abstract
Redox balance is essential for normal brain, hence dis-coordinated oxidative reactions leading to neuronal death, including programs of regulated death, are commonly viewed as an inevitable pathogenic penalty for acute neuro-injury and neurodegenerative diseases. Ferroptosis is one of these programs triggered by dyshomeostasis of three metabolic pillars: iron, thiols, and polyunsaturated phospholipids. This review focuses on: (1) lipid peroxidation (LPO) as the major instrument of cell demise, (2) iron as its catalytic mechanism, and (3) thiols as regulators of pro-ferroptotic signals, hydroperoxy lipids. Given the central role of LPO, we discuss the engagement of selective and specific enzymatic pathways versus random free radical chemical reactions in the context of the phospholipid substrates, their biosynthesis, intracellular location, and related oxygenating machinery as participants in ferroptotic cascades. These concepts are discussed in the light of emerging neuro-therapeutic approaches controlling intracellular production of pro-ferroptotic phospholipid signals and their non-cell-autonomous spreading, leading to ferroptosis-associated necroinflammation.
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Affiliation(s)
- Hülya Bayır
- Children's Neuroscience Institute, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; Center for Free Radical and Antioxidant Health, Department of Environmental Health, University of Pittsburgh, Pittsburgh, PA 15213, USA; Safar Center for Resuscitation Research, Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15224, USA.
| | - Tamil S Anthonymuthu
- Children's Neuroscience Institute, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; Center for Free Radical and Antioxidant Health, Department of Environmental Health, University of Pittsburgh, Pittsburgh, PA 15213, USA; Safar Center for Resuscitation Research, Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Yulia Y Tyurina
- Center for Free Radical and Antioxidant Health, Department of Environmental Health, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Sarju J Patel
- Genetics and Metabolism Section, Liver Diseases Branch, NIDDK, NIH, Bethesda, MD 20892, USA
| | - Andrew A Amoscato
- Center for Free Radical and Antioxidant Health, Department of Environmental Health, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Andrew M Lamade
- Children's Neuroscience Institute, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; Center for Free Radical and Antioxidant Health, Department of Environmental Health, University of Pittsburgh, Pittsburgh, PA 15213, USA; Safar Center for Resuscitation Research, Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Qin Yang
- Children's Neuroscience Institute, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; Center for Free Radical and Antioxidant Health, Department of Environmental Health, University of Pittsburgh, Pittsburgh, PA 15213, USA; Safar Center for Resuscitation Research, Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Georgy K Vladimirov
- Center for Free Radical and Antioxidant Health, Department of Environmental Health, University of Pittsburgh, Pittsburgh, PA 15213, USA; Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Caroline C Philpott
- Genetics and Metabolism Section, Liver Diseases Branch, NIDDK, NIH, Bethesda, MD 20892, USA
| | - Valerian E Kagan
- Children's Neuroscience Institute, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; Center for Free Radical and Antioxidant Health, Department of Environmental Health, University of Pittsburgh, Pittsburgh, PA 15213, USA; Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, 119991 Moscow, Russia.
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7
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Sands KN, Back TG. Key steps and intermediates in the catalytic mechanism for the reduction of peroxides by the antioxidant ebselen. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.05.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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8
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Jaromin A, Zarnowski R, Piętka-Ottlik M, Andes DR, Gubernator J. Topical delivery of ebselen encapsulated in biopolymeric nanocapsules: drug repurposing enhanced antifungal activity. Nanomedicine (Lond) 2018; 13:1139-1155. [DOI: 10.2217/nnm-2017-0337] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Aim: Ebselen (Eb) is an example of a repurposed drug with poor aqueous solubility which requires sophisticated delivery system such as nanoencapsulation in nanocapsules for topical application. Materials & methods: Eb-nanocapsules were examined for morphology, activity against Candida spp., cytotoxicity and skin permeation. Results: Eb-nanocapsules were active against skin-infecting Candida tropicalis, Candida albicans and Candida parapsilosis yeasts (minimal inhibitory concentration values were about 4-, 2- and 1.25-times lower vs free Eb, respectively) and able to suppress induced lipid oxidation in the oil/water emulsion. Moreover, demonstrated minimal toxicity in normal human dermal fibroblast cell line, whereas ex vivo skin permeation studies showed no transdermal passage and strong interactions with stratum corneum. Conclusion: Eb-nanocapsules represent a promising, safe and complementary alternative to the treatment of cutaneous candidiasis.
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Affiliation(s)
- Anna Jaromin
- Department of Lipids & Liposomes, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50–383 Wroclaw, Poland
| | - Robert Zarnowski
- Department of Medicine, Section of Infectious Diseases, 5225 Microbial Sciences Building, 1550 Linden Dr, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Magdalena Piętka-Ottlik
- Department of Organic & Pharmaceutical Technology, Faculty of Chemistry, Wroclaw University of Science & Technology, Wybrzeze Wyspianskiego 27, 50–370 Wroclaw, Poland
| | - David R Andes
- Department of Medicine, Section of Infectious Diseases, 5225 Microbial Sciences Building, 1550 Linden Dr, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jerzy Gubernator
- Department of Lipids & Liposomes, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50–383 Wroclaw, Poland
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9
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Barbosa NV, Nogueira CW, Nogara PA, de Bem AF, Aschner M, Rocha JBT. Organoselenium compounds as mimics of selenoproteins and thiol modifier agents. Metallomics 2017; 9:1703-1734. [PMID: 29168872 DOI: 10.1039/c7mt00083a] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Selenium is an essential trace element for animals and its role in the chemistry of life relies on a unique functional group: the selenol (-SeH) group. The selenol group participates in critical redox reactions. The antioxidant enzymes glutathione peroxidase (GPx) and thioredoxin reductase (TrxR) exemplify important selenoproteins. The selenol group shares several chemical properties with the thiol group (-SH), but it is much more reactive than the sulfur analogue. The substitution of S by Se has been exploited in organic synthesis for a long time, but in the last 4 decades the re-discovery of ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) and the demonstration that it has antioxidant and therapeutic properties has renovated interest in the field. The ability of ebselen to mimic the reaction catalyzed by GPx has been viewed as the most important molecular mechanism of action of this class of compound. The term GPx-like or thiol peroxidase-like reaction was previously coined in the field and it is now accepted as the most important chemical attribute of organoselenium compounds. Here, we will critically review the literature on the capacity of organoselenium compounds to mimic selenoproteins (particularly GPx) and discuss some of the bottlenecks in the field. Although the GPx-like activity of organoselenium compounds contributes to their pharmacological effects, the superestimation of the GPx-like activity has to be questioned. The ability of these compounds to oxidize the thiol groups of proteins (the thiol modifier effects of organoselenium compounds) and to spare selenoproteins from inactivation by soft-electrophiles (MeHg+, Hg2+, Cd2+, etc.) might be more relevant for the explanation of their pharmacological effects than their GPx-like activity. In our view, the exploitation of the thiol modifier properties of organoselenium compounds can be harnessed more rationally than the use of low mass molecular structures to mimic the activity of high mass macromolecules that have been shaped by millions to billions of years of evolution.
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Affiliation(s)
- Nilda V Barbosa
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
| | - Cristina W Nogueira
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
| | - Pablo A Nogara
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
| | - Andreza F de Bem
- Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
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Watanabe K, Tanaka M, Yuki S, Hirai M, Yamamoto Y. How is edaravone effective against acute ischemic stroke and amyotrophic lateral sclerosis? J Clin Biochem Nutr 2017; 62:20-38. [PMID: 29371752 PMCID: PMC5773834 DOI: 10.3164/jcbn.17-62] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 07/11/2017] [Indexed: 12/12/2022] Open
Abstract
Edaravone is a low-molecular-weight antioxidant drug targeting peroxyl radicals among many types of reactive oxygen species. Because of its amphiphilicity, it scavenges both lipid- and water-soluble peroxyl radicals by donating an electron to the radical. Thus, it inhibits the oxidation of lipids by scavenging chain-initiating water-soluble peroxyl radicals and chain-carrying lipid peroxyl radicals. In 2001, it was approved in Japan as a drug to treat acute-phase cerebral infarction, and then in 2015 it was approved for amyotrophic lateral sclerosis (ALS). In 2017, the U.S. Food and Drug Administration also approved edaravone for treatment of patients with ALS. Its mechanism of action was inferred to be scavenging of peroxynitrite. In this review, we focus on the radical-scavenging characteristics of edaravone in comparison with some other antioxidants that have been studied in clinical trials, and we summarize its pharmacological action and clinical efficacy in patients with acute cerebral infarction and ALS.
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Affiliation(s)
- Kazutoshi Watanabe
- Sohyaku. Innovative Research Division, Mitsubishi Tanabe Pharma Corporation, 1000 Kamoshida-cho, Aoba-ku, Yokohama 227-0033, Japan
| | - Masahiko Tanaka
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura-cho, Hachioji 192-0982, Japan
| | - Satoshi Yuki
- Ikuyaku. Integrated Value Development Division, Mitsubishi Tanabe Pharma Corporation, 17-10 Nihonbashi-Koamicho, Chuo-ku, Tokyo 103-8405, Japan
| | - Manabu Hirai
- Ikuyaku. Integrated Value Development Division, Mitsubishi Tanabe Pharma Corporation, 3-2-10 Dosho-machi, Chuo-ku, Osaka 541-8505, Japan
| | - Yorihiro Yamamoto
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura-cho, Hachioji 192-0982, Japan
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11
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Thangamani S, Eldesouky HE, Mohammad H, Pascuzzi PE, Avramova L, Hazbun TR, Seleem MN. Ebselen exerts antifungal activity by regulating glutathione (GSH) and reactive oxygen species (ROS) production in fungal cells. Biochim Biophys Acta Gen Subj 2016; 1861:3002-3010. [PMID: 27712973 DOI: 10.1016/j.bbagen.2016.09.029] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 09/27/2016] [Accepted: 09/28/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND Ebselen, an organoselenium compound and a clinically safe molecule has been reported to possess potent antifungal activity, but its antifungal mechanism of action and in vivo antifungal activity remain unclear. METHODS The antifungal effect of ebselen was tested against Candida albicans, C. glabrata, C. tropicalis, C. parapsilosis, Cryptococcus neoformans, and C. gattii clinical isolates. Chemogenomic profiling and biochemical assays were employed to identify the antifungal target of ebselen. Ebselen's antifungal activity in vivo was investigated in a Caenorhabditis elegans animal model. RESULTS Ebselen exhibits potent antifungal activity against both Candida spp. and Cryptococcus spp., at concentrations ranging from 0.5 to 2μg/ml. Ebselen rapidly eradicates a high fungal inoculum within 2h of treatment. Investigation of the drug's antifungal mechanism of action indicates that ebselen depletes intracellular glutathione (GSH) levels, leading to increased production of reactive oxygen species (ROS), and thereby disturbs the redox homeostasis in fungal cells. Examination of ebselen's in vivo antifungal activity in two Caenorhabditis elegans models of infection demonstrate that ebselen is superior to conventional antifungal drugs (fluconazole, flucytosine and amphotericin) in reducing Candida and Cryptococcus fungal load. CONCLUSION Ebselen possesses potent antifungal activity against clinically relevant isolates of both Candida and Cryptococcus by regulating GSH and ROS production. The potent in vivo antifungal activity of ebselen supports further investigation for repurposing it for use as an antifungal agent. GENERAL SIGNIFICANCE The present study shows that ebselen targets glutathione and also support that glutathione as a potential target for antifungal drug development.
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Affiliation(s)
- Shankar Thangamani
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Hassan E Eldesouky
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Haroon Mohammad
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Pete E Pascuzzi
- Faculty in Libraries, Purdue University, West Lafayette, IN 47906, USA
| | - Larisa Avramova
- Bindley Bioscience Center, Purdue University, West Lafayette, IN 47906, USA
| | - Tony R Hazbun
- Bindley Bioscience Center, Purdue University, West Lafayette, IN 47906, USA; Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47906, USA.
| | - Mohamed N Seleem
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA; Purdue Institute for Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA.
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12
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Patel M. Targeting Oxidative Stress in Central Nervous System Disorders. Trends Pharmacol Sci 2016; 37:768-778. [PMID: 27491897 DOI: 10.1016/j.tips.2016.06.007] [Citation(s) in RCA: 193] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 12/12/2022]
Abstract
There is widespread recognition that reactive oxygen species (ROS) play key roles in normal brain function and pathology in the context of neurological disease. Oxidative stress continues to be a key therapeutic target for neurological diseases. In developing antioxidant therapies for neurological disease, special attention should be given to the brain's unique vulnerability to oxidative insults and its architecture. Consideration of antioxidant therapy should be guided by a strong rationale for oxidative stress in a given neurological disease. This review provides an overview of processes that can guide the development of antioxidant therapies in neurological diseases, such as knowledge of basic redox mechanisms, unique features of brain pathophysiology, mechanisms and classes of antioxidants, and desirable properties of drug candidates.
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Affiliation(s)
- Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
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13
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Davis MT, Bartfay WJ. Ebselen Decreases Oxygen Free Radical Production and Iron Concentrations in the Hearts of Chronically Iron-Overloaded Mice. Biol Res Nurs 2016; 6:37-45. [PMID: 15186706 DOI: 10.1177/1099800403261350] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chronic iron overload is a major cause of cardiac failure throughout the world, but its pathogenesis remains to be clarified. It is conjectured that the toxicity of iron is due to its ability to catalyze the formation of oxygen free radicals (OFR), which can damage cellular membranes, proteins, and DNA. The authors report on the cardioprotective effects of the glutathione peroxidase (GPx) mimic ebselen on iron concentrations in the heart and GPx activity, and on the production of the cytotoxic aldehydes hexanal, 4-hydroxyl-2-nonenal (HNE), and malondialdehyde (MDA). Fifteen B6D2F1 mice were randomized to 1 of 3 treatment groups for a total of 20 treatments: 1) control (0.1 mL normal saline i.p. per mouse, per day); 2) iron-only (10 mg iron dextran i.p. per mouse, per day); 3) iron plus ebselen (25 mg/kg p.o. per mouse, per day). In comparison to iron-only treated mice, the authors’ findings show that supplementation with ebselen can decrease both cytotoxic aldehyde and iron concentrations in heart tissue. Additionally, mice supplemented with ebselen had an increase in GPx activity level in comparison to iron-only treated mice. To the authors’knowledge, this is the first study to examine the cardioprotective effects of ebselen against OFR damage in a model of chronic iron overload. These findings suggest that ebselen may have significance in the management of disorders of iron overload.
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Affiliation(s)
- Matthew T Davis
- School of Nursing at Queen's University, Kingston, ON, Canada
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14
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Noguchi N. Ebselen, a useful tool for understanding cellular redox biology and a promising drug candidate for use in human diseases. Arch Biochem Biophys 2016; 595:109-12. [DOI: 10.1016/j.abb.2015.10.024] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 10/09/2015] [Accepted: 10/09/2015] [Indexed: 12/19/2022]
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15
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Thangamani S, Younis W, Seleem MN. Repurposing ebselen for treatment of multidrug-resistant staphylococcal infections. Sci Rep 2015; 5:11596. [PMID: 26111644 PMCID: PMC4481386 DOI: 10.1038/srep11596] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 05/21/2015] [Indexed: 12/11/2022] Open
Abstract
Novel antimicrobials and new approaches to developing them are urgently needed. Repurposing already-approved drugs with well-characterized toxicology and pharmacology is a novel way to reduce the time, cost, and risk associated with antibiotic innovation. Ebselen, an organoselenium compound, is known to be clinically safe and has a well-known pharmacology profile. It has shown potent bactericidal activity against multidrug-resistant clinical isolates of staphylococcus aureus, including methicillin- and vancomycin-resistant S. aureus (MRSA and VRSA). We demonstrated that ebselen acts through inhibition of protein synthesis and subsequently inhibited toxin production in MRSA. Additionally, ebselen was remarkably active and significantly reduced established staphylococcal biofilms. The therapeutic efficacy of ebselen was evaluated in a mouse model of staphylococcal skin infections. Ebselen 1% and 2% significantly reduced the bacterial load and the levels of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and monocyte chemo attractant protein-1 (MCP-1) in MRSA USA300 skin lesions. Furthermore, it acts synergistically with traditional antimicrobials. This study provides evidence that ebselen has great potential for topical treatment of MRSA skin infections and lays the foundation for further analysis and development of ebselen as a potential treatment for multidrug-resistant staphylococcal infections.
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Affiliation(s)
- Shankar Thangamani
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA
| | - Waleed Younis
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA
| | - Mohamed N Seleem
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA
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16
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Lulla A, Reznik S, Trombetta L, Billack B. Use of the mouse ear vesicant model to evaluate the effectiveness of ebselen as a countermeasure to the nitrogen mustard mechlorethamine. J Appl Toxicol 2013; 34:1373-8. [DOI: 10.1002/jat.2969] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 10/10/2013] [Accepted: 11/07/2013] [Indexed: 12/24/2022]
Affiliation(s)
- Anju Lulla
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences; St. John's University; Jamaica NY 11439 USA
| | - Sandra Reznik
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences; St. John's University; Jamaica NY 11439 USA
| | - Louis Trombetta
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences; St. John's University; Jamaica NY 11439 USA
| | - Blase Billack
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences; St. John's University; Jamaica NY 11439 USA
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17
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The early research and development of ebselen. Biochem Pharmacol 2013; 86:1248-53. [DOI: 10.1016/j.bcp.2013.08.028] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 08/21/2013] [Accepted: 08/23/2013] [Indexed: 11/22/2022]
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18
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Mahadevan J, Parazzoli S, Oseid E, Hertzel AV, Bernlohr DA, Vallerie SN, Liu CQ, Lopez M, Harmon JS, Robertson RP. Ebselen treatment prevents islet apoptosis, maintains intranuclear Pdx-1 and MafA levels, and preserves β-cell mass and function in ZDF rats. Diabetes 2013; 62:3582-8. [PMID: 23801580 PMCID: PMC3781455 DOI: 10.2337/db13-0357] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We reported earlier that β-cell-specific overexpression of glutathione peroxidase (GPx)-1 significantly ameliorated hyperglycemia in diabetic db/db mice and prevented glucotoxicity-induced deterioration of β-cell mass and function. We have now ascertained whether early treatment of Zucker diabetic fatty (ZDF) rats with ebselen, an oral GPx mimetic, will prevent β-cell deterioration. No other antihyperglycemic treatment was given. Ebselen ameliorated fasting hyperglycemia, sustained nonfasting insulin levels, lowered nonfasting glucose levels, and lowered HbA1c levels with no effects on body weight. Ebselen doubled β-cell mass, prevented apoptosis, prevented expression of oxidative stress markers, and enhanced intranuclear localization of pancreatic and duodenal homeobox (Pdx)-1 and v-maf musculoaponeurotic fibrosarcoma oncogene family, protein A (MafA), two critical insulin transcription factors. Minimal β-cell replication was observed in both groups. These findings indicate that prevention of oxidative stress is the mechanism whereby ebselen prevents apoptosis and preserves intranuclear Pdx-1 and MafA, which, in turn, is a likely explanation for the beneficial effects of ebselen on β-cell mass and function. Since ebselen is an oral antioxidant currently used in clinical trials, it is a novel therapeutic candidate to ameliorate fasting hyperglycemia and further deterioration of β-cell mass and function in humans undergoing the onset of type 2 diabetes.
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Affiliation(s)
- Jana Mahadevan
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Susan Parazzoli
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Elizabeth Oseid
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Ann V. Hertzel
- Department of Biochemistry and Molecular Biology, University of Minnesota, Minneapolis, Minnesota
| | - David A. Bernlohr
- Department of Biochemistry and Molecular Biology, University of Minnesota, Minneapolis, Minnesota
| | - Sara N. Vallerie
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Chang-qin Liu
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Melissa Lopez
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Jamie S. Harmon
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - R. Paul Robertson
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
- Department of Biochemistry and Molecular Biology, University of Minnesota, Minneapolis, Minnesota
- Corresponding author: R. Paul Robertson,
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19
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Mouithys-Mickalad Mareque A, Faez JM, Chistiaens L, Kohnen S, Deby C, Hoebeke M, Lamy M, Deby-Dupont G. In vitroevaluation of glutathione peroxidase (GPx)-like activity and antioxidant properties of some Ebselen analogues. Redox Rep 2013; 9:81-7. [PMID: 15231062 DOI: 10.1179/135100004225004788] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Four analogues of Ebselen were synthesized and their glutathione peroxidase activity and antioxidant property evaluated and compared to Ebselen. Among the studied compounds, only diselenide [3] exhibited both glutathione peroxidase activity and radical-scavenging capability. Compounds [3] and [4] showed a strong inhibitory effect (53% and 43%, respectively) on the lipid peroxidation of linoleic acid compared to Ebselen and selenide derivatives ([1] and [2]) which were less active (28%, 26% and 18% inhibition, respectively). A concentration-dependent inhibitory effect was also found in the model of the formation of ABTS*+ radical cation: 65% and 89% inhibition for compound [3] at 10(-4) M and 5 x 10(-5) M, respectively, and 68% and 90% for compound [4], compared to 14% and 52% inhibition for Ebselen and the diselenides [1] and [2] (29%, 46% and 45%, 68%, respectively). By EPR spin trapping technique, the following inhibitory profile of the Ebselen analogues was observed towards the formation of thiyl radicals: Ebselen = [3]>[1]>[2]>[4]. Studies with compound [3] are in progress on oxidative stress cell models.
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20
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Pino MA, Pietka-Ottlik M, Billack B. Selected ebselen analogs reduce mechlorethamine toxicityin vitro. Cutan Ocul Toxicol 2013; 33:32-41. [DOI: 10.3109/15569527.2013.794818] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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21
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Lulla A, Pino MA, Piętka-Ottlik M, Młochowski J, Sparavalo O, Billack B. Ebselen Reduces the Toxicity of Mechlorethamine in A-431 Cells via Inhibition of Apoptosis. J Biochem Mol Toxicol 2013; 27:313-22. [DOI: 10.1002/jbt.21490] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 03/27/2013] [Accepted: 04/03/2013] [Indexed: 01/01/2023]
Affiliation(s)
- Anju Lulla
- Department of Pharmaceutical Sciences; College of Pharmacy and Health Sciences, St. John's University; Jamaica; NY; 11439; USA
| | - Maria A. Pino
- Department of Pharmaceutical Sciences; College of Pharmacy and Health Sciences, St. John's University; Jamaica; NY; 11439; USA
| | - Magdalena Piętka-Ottlik
- Department of Organic Technology; Faculty of Chemistry, Wrocław University of Technology; PL 50-370 Wrocław; Poland
| | - Jacek Młochowski
- Department of Organic Chemistry; Faculty of Chemistry, Wrocław University of Technology; PL 50-370 Wrocław; Poland
| | - Oleksiy Sparavalo
- Department of Pharmaceutical Sciences; College of Pharmacy and Health Sciences, St. John's University; Jamaica; NY; 11439; USA
| | - Blase Billack
- Department of Pharmaceutical Sciences; College of Pharmacy and Health Sciences, St. John's University; Jamaica; NY; 11439; USA
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22
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Rzepczynska IJ, Foyouzi N, Piotrowski PC, Celik-Ozenci C, Cress A, Duleba AJ. Antioxidants induce apoptosis of rat ovarian theca-interstitial cells. Biol Reprod 2010; 84:162-6. [PMID: 20844276 DOI: 10.1095/biolreprod.110.087585] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Regulation of growth of ovarian theca-interstitial tissues is essential for normal ovarian development and function. Reactive oxygen species are involved in modulation of signal transduction pathways, including regulation of tissue growth and apoptosis. Previously, we have demonstrated that antioxidants inhibit proliferation of theca-interstitial cells. This report evaluates the effects of antioxidants on apoptosis of rat theca-interstitial cells. The cells were cultured in chemically defined media without or with vitamin E succinate and ebselen. Apoptosis was evaluated by cytochemical assessment of nuclear morphology, activity of executioner caspases 3 and 7, and determination of staining with annexin V in combination with propidium iodide. Both tested antioxidants induced significant morphological changes consistent with apoptosis, including chromatin condensation, nuclear shrinkage, and pyknosis. Antioxidants also induced other hallmarks of apoptosis including increased activity of caspases 3/7 as well as increased staining with annexin V. The present findings demonstrate that antioxidants with distinctly different mechanisms of action induce a series of events consistent with the process of apoptosis in ovarian mesenchyme. These observations may be of translational-clinical relevance, providing mechanistic support for the use of antioxidants in the treatment of PCOS, a condition associated with excessive growth and activity of theca-interstitial cells.
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Affiliation(s)
- Izabela J Rzepczynska
- Department of Gynecology and Obstetrics, Poznan University of Medical Sciences, Poznan, Poland
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23
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Páramo B, Hernández-Fonseca K, Estrada-Sánchez AM, Jiménez N, Hernández-Cruz A, Massieu L. Pathways involved in the generation of reactive oxygen and nitrogen species during glucose deprivation and its role on the death of cultured hippocampal neurons. Neuroscience 2010; 167:1057-69. [PMID: 20226235 DOI: 10.1016/j.neuroscience.2010.02.074] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 02/25/2010] [Accepted: 02/28/2010] [Indexed: 10/19/2022]
Abstract
Oxidative stress has been suggested as a mechanism contributing to neuronal death induced by hypoglycemia, and an early production of reactive species (RS) during the hypoglycemic episode has been observed. However, the sources of reactive oxygen (ROS) and nitrogen (RNS) species have not been fully identified. In the present study we have examined the contribution of various enzymatic pathways to RS production and neuronal death induced by glucose deprivation (GD) in hippocampal cultures. We have observed a rapid increase in RS during GD, which depends on the activation of NMDA and non-NMDA receptors and on the influx of calcium from the extracellular space. Accordingly, intracellular calcium concentration [Ca(2+)](i) progressively increases more than 30-fold during the GD period. It was observed that superoxide production through the activation of the calcium-dependent enzymes, phospholipase A(2) (cPLA(2)) and xanthine oxidase (XaO), contributes to neuronal damage, while nitric oxide synthase (NOS) is apparently not involved. Inhibition of cPLA(2) decreased RS at early times of GD whereas inhibition of XaO diminished RS at more delayed times. The antioxidants trolox and ebselen also showed a protective effect against neuronal death and diminished RS generation. Inhibition of NADPH oxidase also contributed to the early generation of superoxide. Taking together, the present results suggest that the early activation of calcium-dependent ROS producing pathways is involved in neuronal death associated with glucose deprivation.
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Affiliation(s)
- B Páramo
- División de Neurociencias, Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., México, CP 04510, AP 70-253
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24
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Steinbrenner H, Sies H. Protection against reactive oxygen species by selenoproteins. Biochim Biophys Acta Gen Subj 2009; 1790:1478-85. [PMID: 19268692 DOI: 10.1016/j.bbagen.2009.02.014] [Citation(s) in RCA: 520] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 02/27/2009] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species (ROS) are derived from cellular oxygen metabolism and from exogenous sources. An excess of ROS results in oxidative stress and may eventually cause cell death. ROS levels within cells and in extracellular body fluids are controlled by concerted action of enzymatic and non-enzymatic antioxidants. The essential trace element selenium exerts its antioxidant function mainly in the form of selenocysteine residues as an integral constituent of ROS-detoxifying selenoenzymes such as glutathione peroxidases (GPx), thioredoxin reductases (TrxR) and possibly selenoprotein P (SeP). In particular, the dual role of selenoprotein P as selenium transporter and antioxidant enzyme is highlighted herein. A cytoprotective effect of selenium supplementation has been demonstrated for various cell types including neurons and astrocytes as well as endothelial cells. Maintenance of full GPx and TrxR activity by adequate dietary selenium supply has been proposed to be useful for the prevention of several cardiovascular and neurological disorders. On the other hand, selenium supplementation at supranutritional levels has been utilised for cancer prevention: antioxidant selenoenzymes as well as prooxidant effects of selenocompounds on tumor cells are thought to be involved in the anti-carcinogenic action of selenium.
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Affiliation(s)
- Holger Steinbrenner
- Institute for Biochemistry and Molecular Biology I, Heinrich-Heine-University, Düsseldorf, Germany
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Tavori H, Aviram M, Khatib S, Musa R, Nitecki S, Hoffman A, Vaya J. Human carotid atherosclerotic plaque increases oxidative state of macrophages and low-density lipoproteins, whereas paraoxonase 1 (PON1) decreases such atherogenic effects. Free Radic Biol Med 2009; 46:607-15. [PMID: 19103284 DOI: 10.1016/j.freeradbiomed.2008.11.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 11/13/2008] [Accepted: 11/16/2008] [Indexed: 02/06/2023]
Abstract
Human atherosclerotic plaque contains a variety of oxidized lipids, which can facilitate further oxidation. Paraoxonase 1 (PON1) is a high-density lipoprotein (HDL)-associated esterase (lipolactonase), exhibiting antiatherogenic properties. The aims of the present study were to examine the oxidizing potency of the human carotid plaque lipid extract (LE), and the antiatherogenic role of PON1 on LE oxidation competence. Human carotid plaques were extracted by organic solvent, and the extract was incubated with lipoprotein particles, with macrophages, or with probes sensitive to oxidative stress, with or without preincubation with PON1, followed by oxidative-stress assessment. Our findings imply that the LE oxidized LDL, macrophages, and exogenous probes and decreases HDL-mediated cholesterol efflux from macrophages, in a dose-dependent manner. Incubation of PON1 with LE significantly affects LE composition, reduces LE atherogenic properties, and decreases the extract's total peroxide concentration by 44%, macrophage oxidation by 25%, and probe oxidation by up to 52%. We conclude that these results expand our understanding of how the plaque itself accelerates atherogenesis and provides an important mechanism for attenuation of atherosclerosis development by the antioxidant action of PON1 on the atherosclerotic plaque.
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Affiliation(s)
- Hagai Tavori
- MIGAL - Galilee Technology Center, Kiryat Shmona, Tel Hai College, Israel
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26
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Parnham MJ. Section Review Pulmonary-Allergy, Dermatological, Gastrointestinal & Arthritis: The pharmaceutical potential of seleno-organic compounds. Expert Opin Investig Drugs 2008. [DOI: 10.1517/13543784.5.7.861] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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27
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Scholz M, Ulbrich HK, Dannhardt G. Investigations concerning the COX/5-LOX inhibiting and hydroxyl radical scavenging potencies of novel 4,5-diaryl isoselenazoles. Eur J Med Chem 2007; 43:1152-9. [PMID: 17976864 DOI: 10.1016/j.ejmech.2007.09.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 07/30/2007] [Accepted: 09/06/2007] [Indexed: 11/16/2022]
Abstract
The aim of this study was to investigate 4,5-diaryl isoselenazoles as multiple target non-steroidal anti-inflammatory drugs (MTNSAIDs) which can intervene into the inflammatory processes via different mechanisms of action creating a new class of compounds. Here we describe the synthesis of COX/LOX inhibitors which additionally reduce the level of reactive oxygen species, such as hydroxyl radicals which are well known for supporting inflammation processes in Parkinson's disease, Alzheimer's disease and rheumatoid arthritis.
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Affiliation(s)
- Michael Scholz
- Institute of Pharmacy, Department of Pharmaceutical and Medicinal Chemistry, Johannes Gutenberg University, Staudingerweg 5, DE-55128 Mainz, Germany
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28
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Chan G, Hardej D, Santoro M, Lau-Cam C, Billack B. Evaluation of the antimicrobial activity of ebselen: Role of the yeast plasma membrane H+-ATPase. J Biochem Mol Toxicol 2007; 21:252-64. [PMID: 17912695 DOI: 10.1002/jbt.20189] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) is a selenium-containing antioxidant demonstrating anti-inflammatory and cytoprotective properties in mammalian cells and cytotoxicity in lower organisms. The mechanism underlying the antimicrobial activity of ebselen remains unclear. It has recently been proposed that, in lower organisms like yeast, the plasma membrane H+-ATPase (Pma1p) could serve as a potential target for this synthetic organoselenium compound. Using yeast and bacteria, the present study found ebselen to inhibit microbial growth in a concentration- and time-dependent manner, and yeast and Gram-positive bacteria to be more sensitive to this action (IC50 approximately 2-5 microM) than Gram-negative bacteria (IC50 < 80 microM). Washout experiments and scanning electron microscopic analysis revealed ebselen to possess fungicidal activity. In addition, ebselen was found to inhibit medium acidification by PMA1-proficient haploid yeast in a concentration-dependent manner. Additional studies comparing PMA1 (+/-) and PMA1 (+/+) diploid yeast cells revealed the mutant to be more sensitive to treatment with ebselen than the wild type. Ebselen also inhibited the ATPase activity of Pma1p from S. cerevisiae in a concentration-dependent manner. The interaction of ebselen with the sulfhydryl-containing compounds L-cysteine and reduced glutathione resulted in the complete and partial prevention, respectively, of the inhibition of Pma1p ATPase activity by ebselen. Taken together, these results suggest that the fungicidal action of ebselen is due, at least in part, to interference with both the proton-translocating function and the ATPase activity of the plasma membrane H+-ATPase.
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Affiliation(s)
- Grace Chan
- Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John's University, Jamaica, NY 11439, USA
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Mishra B, Priyadarsini KI, Mohan H, Mugesh G. Horseradish peroxidase inhibition and antioxidant activity of ebselen and related organoselenium compounds. Bioorg Med Chem Lett 2006; 16:5334-8. [PMID: 16919452 DOI: 10.1016/j.bmcl.2006.07.085] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 07/10/2006] [Accepted: 07/26/2006] [Indexed: 01/01/2023]
Abstract
Horseradish peroxidase (HRP) inhibition and glutathione peroxidase (GPx) activities of ebselen and some related derivatives are described. These studies show that ebselen and ebselen ditelluride (EbTe(2)) with significant antioxidant activity, inhibit the HRP-catalyzed oxidation reactions. In addition, inhibition of lipid peroxidation and singlet oxygen quenching studies were carried out. Although the inhibition of HRP by ebselen is comparable with that of EbTe(2), the inhibitory effect on gamma-radiation induced lipid peroxidation and the GPx activity of ebselen is found to be much higher than that of EbTe(2).
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Affiliation(s)
- Beena Mishra
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 85, India
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30
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Steffen Y, Wiswedel I, Peter D, Schewe T, Sies H. Cytotoxicity of myeloperoxidase/nitrite-oxidized low-density lipoprotein toward endothelial cells is due to a high 7beta-hydroxycholesterol to 7-ketocholesterol ratio. Free Radic Biol Med 2006; 41:1139-50. [PMID: 16962939 DOI: 10.1016/j.freeradbiomed.2006.06.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 06/14/2006] [Accepted: 06/30/2006] [Indexed: 12/24/2022]
Abstract
Oxygenated cholesterols (oxysterols) formed during oxidation of low-density lipoprotein (LDL) are associated with endothelial dysfunction and atherogenesis. We compared the profile of oxysterols in modified human LDL obtained on reaction with myeloperoxidase/H2O2 plus nitrite (MPO/H2O2/nitrite-oxLDL) with that on Cu2+ -catalyzed oxidation. The 7beta-hydroxycholesterol/7-ketocholesterol ratio was markedly higher in MPO/H2O2/nitrite-oxLDL than in Cu2+ -oxidized LDL (7.9 +/- 3.0 versus 0.94 +/- 0.10). Like MPO/H2O2/nitrite-oxLDL, 7beta-hydroxycholesterol was cytotoxic toward endothelial cells through eliciting oxidative stress. Cytotoxicity was accompanied by DNA fragmentation and was prevented by the NADPH oxidase inhibitor apocynin, suggesting stimulation of NADPH oxidase-mediated O2-* formation. 7-Ketocholesterol was only cytotoxic when added alone, whereas a 1:1-mixture with 7beta-hydroxycholesterol surprisingly was noncytotoxic. We conclude from our data that (i) 7beta-hydroxycholesterol is a pivotal cytotoxic component of oxidized LDL, (ii) 7-ketocholesterol protects against 7beta-hydroxycholesterol in oxysterol mixtures or oxLDL, (iii) the 7beta-hydroxycholesterol/7-ketocholesterol ratio is a crucial determinant for cytotoxicity of oxidized LDL species and oxysterol mixtures, and (iv) the low share of 7-ketocholesterol explains the higher cytotoxicity of MPO/H2O2/nitrite-oxLDL than other forms of oxidized LDL. The dietary polyphenol (-)-epicatechin inhibited not only formation but also cytotoxic actions of both oxLDL and oxysterols.
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Affiliation(s)
- Yvonne Steffen
- Institut für Biochemie und Molekularbiologie I, Heinrich-Heine-Universität, Postfach 101007, D-40001 Düsseldorf, Germany
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Ocakci A, Coskun O, Tumkaya L, Kanter M, Gurel A, Hosnuter M, Uzun L. Beneficial effects of Ebselen on corrosive esophageal burns of rats. Int J Pediatr Otorhinolaryngol 2006; 70:45-52. [PMID: 15979162 DOI: 10.1016/j.ijporl.2005.05.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Accepted: 05/10/2005] [Indexed: 02/03/2023]
Abstract
AIM This study was evaluated to investigate the efficacy of Ebselen, which is an organoselenium compound and glutathione peroxidase mimic, on the prevention of stricture development after esophageal caustic injuries in the rat. METHODS Thirty healthy male Wistar albino rats were utilized in this study. The rats were randomly allotted into one of three experimental groups: group A (sham) animals were uninjured. Caustic esophageal burn was created by applying 1 ml of 37.5% NaOH to the distal esophagus. Group B rats were injured but untreated. Group C rats were injured and received Ebselen (10 mg/kg/day) via the oral route. Blood and tissue samples for the biochemical and histopathological analysis were taken all rats at the end (28th day) of the experiment. Oxidative stress is believed to play a role in the pathogenesis of corrosive esophageal burns. To assess changes in the cellular antioxidant defense system, we measured the activities of antioxidant enzymes (such as glutathione peroxidase (GSHPx), superoxide dismutase (SOD), and catalase (CAT)) in esophagus homogenates. We also measured esophageal tissue malondialdehyde (MDA) levels, a marker of lipid peroxidation, to determine whether there is an imbalance between oxidant and antioxidant status. Efficacy of the treatment was assessed by measuring the stenosis index and histopathologic damage score and biochemically by determining tissue hydroxyproline content, lipid peroxidation and antioxidant enzyme levels. RESULTS The stenosis index in group B was significantly increased compared with group A and C (P<0.05). The hydroxyproline level was significantly increased in group B compared with group A and C (P<0.05). In group B, the histopathologic damage score was significantly higher than in group C (P<0.05). Treatment with Ebselen decreased tissue hydroxyproline levels, histological damage, and the stenosis index. Caustic esophageal burn increased the lipid peroxidation and also decreased the antioxidant enzyme levels in group B. Ebselen treatments for 28 days decreased the elevated lipid peroxidation and also increased the reduced antioxidant enzyme levels. Live weights of the rats was significantly decreased in group B compared with group A and C (P<0.05). CONCLUSION It is concluded that Ebselen has a preventive effect in the development of fibrosis and decrease the lipid peroxidation, and increase the antioxidant defense system activity in an experimental model of corrosive esophagitis in rats.
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Affiliation(s)
- Ayse Ocakci
- Department of Health High School, Zonguldak Karaelmas University, Zonguldak, Turkey
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Hu L, Chen Z, Lu S, Li X, Liu Z, Xu H. SYNTHESIS OF O,O-DIPHENYL [SUBSTITUTED (2-SELENOMORPHOLIN-4-YL-ACETYL AMINO)] ALKYL PHOSPHONATES. PHOSPHORUS SULFUR 2004. [DOI: 10.1080/10426500490459687] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Nakamura Y, Feng Q, Kumagai T, Torikai K, Ohigashi H, Osawa T, Noguchi N, Niki E, Uchida K. Ebselen, a glutathione peroxidase mimetic seleno-organic compound, as a multifunctional antioxidant. Implication for inflammation-associated carcinogenesis. J Biol Chem 2002; 277:2687-94. [PMID: 11714717 DOI: 10.1074/jbc.m109641200] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ebselen, a seleno-organic compound showing glutathione peroxidase-like activity, is one of the promising synthetic antioxidants. In the present study, we investigated the antioxidant activities of ebselen using a 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated mouse skin model. Double pretreatments of mouse skin with ebselen significantly inhibited TPA-induced formation of thiobarbituric acid-reacting substance, known as an overall oxidative damage biomarker, in mouse epidermis, suggesting that ebselen indeed acts as an antioxidant in mouse skin. The antioxidative effect of ebselen is attributed to its selective blockade of leukocyte infiltration and activation leading to attenuation of the H(2)O(2) level. In in vitro studies, ebselen inhibited TPA-induced superoxide generation in differentiated HL-60 cells and lipopolysaccharide-induced cyclooxygenase-2 protein expression in RAW 264.7 cells. In addition, we demonstrated for the first time that ebselen potentiated phase II enzyme activities, including NAD(P)H:(quinone-acceptor) oxidoreductase1 and glutathione S-transferase in cultured hepatocytes and in mouse skin. These results strongly suggest that ebselen, a multifunctional antioxidant, is a potential chemopreventive agent in inflammation-associated carcinogenesis.
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Affiliation(s)
- Yoshimasa Nakamura
- Laboratory of Food and Biodynamics, Nagoya University Graduate School of Bioagricultural Sciences, Nagoya 464-8601, Japan
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Tiano L, Fedeli D, Ballarini P, Santoni G, Falcioni G. Mitochondrial membrane potential in density-separated trout erythrocytes exposed to oxidative stress in vitro. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1505:226-37. [PMID: 11334787 DOI: 10.1016/s0005-2728(01)00171-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previous literature reports have demonstrated that nucleated trout erythrocytes in condition of oxidative stress are subjected to DNA and membrane damage, and inactivation of glutathione peroxidase. The present study was undertaken to investigate if mitochondrial membrane potential in stressed conditions was also influenced. Density-separated trout erythrocyte fractions, obtained using a discontinuous Percoll gradient, were submitted to stress conditions and the mitochondrial membrane potential was determined by means of cytofluorimetric analysis after incubation of each subfraction with JC-1, a mitochondrial specific fluorescent probe. The results clearly show that the mitochondrial membrane potential decreased significantly in all erythrocyte fractions, also if the oxidative effect on mitochondria is more severe with increased density (age) of the cell. Ebselen was very effective in preventing mitochondrial depolarization in young as well as in old erythrocytes.
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Affiliation(s)
- L Tiano
- Department of Biology MCA, University of Camerino, MC, Italy.
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35
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Wartenberg M, Ling FC, Schallenberg M, Bäumer AT, Petrat K, Hescheler J, Sauer H. Down-regulation of intrinsic P-glycoprotein expression in multicellular prostate tumor spheroids by reactive oxygen species. J Biol Chem 2001; 276:17420-8. [PMID: 11279018 DOI: 10.1074/jbc.m100141200] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Intrinsic expression of the multidrug resistance (MDR) transporter P-glycoprotein (Pgp) may be regulated by reactive oxygen species (ROS). A transient expression of Pgp was observed during the growth of multicellular tumor spheroids. Maximum Pgp expression occurred in tumor spheroids with a high percentage of quiescent, Ki-67-negative cells, elevated glutathione levels, increased expression of the cyclin-dependent kinase inhibitors p27Kip1 and p21WAF-1 as well as reduced ROS levels and minor activity of the mitogen-activated kinase (MAPK) members c-Jun amino-terminal kinase (JNK), extracellular signal-regulated kinase ERK1,2, and p38 MAPK. Raising intracellular ROS by depletion of glutathione with buthionine sulfoximine (BSO) or glutamine starvation resulted in down-regulation of Pgp and p27Kip1, whereas ERK1,2 and JNK were activated. Down-regulation of Pgp was furthermore observed with low concentrations of hydrogen peroxide and epidermal growth factor, indicating that ROS may regulate Pgp expression. The down-regulation of Pgp following BSO treatment was abolished by agents interfering with receptor tyrosine kinase signaling pathways, i.e. the protein kinase C inhibitors bisindolylmaleimide I (BIM-1) and Ro-31-8220, the p21ras farnesyl protein transferase inhibitor III, the c-Raf inhibitor ZM 336372 and PD98059, which inhibits ERK1,2 activation. ROS involved as second messengers in receptor tyrosine kinase signaling pathways may act as negative regulators of Pgp expression.
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Affiliation(s)
- M Wartenberg
- Department of Neurophysiology and the Department III for Internal Medicine, University of Cologne, D-50931 Cologne, Germany
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MAEBA R, SHIMASAKI H, UETA N. Generation of 7-ketocholesterol by a Route Different from the Decomposition of Cholesterol 7-hydroperoxide. J Oleo Sci 2001. [DOI: 10.5650/jos.50.109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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37
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Smooth muscle cell surface tissue factor pathway activation by oxidized low-density lipoprotein requires cellular lipid peroxidation. Blood 2000. [DOI: 10.1182/blood.v96.9.3056] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractTissue factor, which is expressed in vascular lesions, increases thrombin production, blood coagulation, and smooth muscle cell proliferation. We demonstrate that oxidized low-density lipoprotein (LDL) induces surface tissue factor pathway activity (ie, activity of the tissue factor:factor VIIa complex) on human and rat smooth muscle cells. Tissue factor messenger RNA (mRNA) was induced by oxidized LDL or native LDL; however, native LDL did not markedly increase tissue factor activity. We hypothesized that oxidized LDL mediated the activation of the tissue factor pathway via an oxidant-dependent mechanism, because antioxidants blocked the enhanced tissue factor pathway activity by oxidized LDL, but not the increased mRNA or protein induction. We separated total lipid extracts of oxidized LDL using high-performance liquid chromatography (HPLC). This yielded 2 major peaks that induced tissue factor activity. Of the known oxysterols contained in the first peak, 7α- or 7β-hydroxy or 7-ketocholesterol had no effect on tissue factor pathway activity; however, 7β-hydroperoxycholesterol increased tissue factor pathway activity without induction of tissue factor mRNA. Tertiary butyl hydroperoxide also increased tissue factor pathway activity, suggesting that lipid hydroperoxides, some of which exist in atherosclerotic lesions, activate the tissue factor pathway. We speculate that thrombin production could be elevated via a mechanism involving peroxidation of cellular lipids, contributing to arterial thrombosis after plaque rupture. Our data suggest a mechanism by which antioxidants may offer a clinical benefit in acute coronary syndrome and restenosis.
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38
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Smooth muscle cell surface tissue factor pathway activation by oxidized low-density lipoprotein requires cellular lipid peroxidation. Blood 2000. [DOI: 10.1182/blood.v96.9.3056.h8003056_3056_3063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tissue factor, which is expressed in vascular lesions, increases thrombin production, blood coagulation, and smooth muscle cell proliferation. We demonstrate that oxidized low-density lipoprotein (LDL) induces surface tissue factor pathway activity (ie, activity of the tissue factor:factor VIIa complex) on human and rat smooth muscle cells. Tissue factor messenger RNA (mRNA) was induced by oxidized LDL or native LDL; however, native LDL did not markedly increase tissue factor activity. We hypothesized that oxidized LDL mediated the activation of the tissue factor pathway via an oxidant-dependent mechanism, because antioxidants blocked the enhanced tissue factor pathway activity by oxidized LDL, but not the increased mRNA or protein induction. We separated total lipid extracts of oxidized LDL using high-performance liquid chromatography (HPLC). This yielded 2 major peaks that induced tissue factor activity. Of the known oxysterols contained in the first peak, 7α- or 7β-hydroxy or 7-ketocholesterol had no effect on tissue factor pathway activity; however, 7β-hydroperoxycholesterol increased tissue factor pathway activity without induction of tissue factor mRNA. Tertiary butyl hydroperoxide also increased tissue factor pathway activity, suggesting that lipid hydroperoxides, some of which exist in atherosclerotic lesions, activate the tissue factor pathway. We speculate that thrombin production could be elevated via a mechanism involving peroxidation of cellular lipids, contributing to arterial thrombosis after plaque rupture. Our data suggest a mechanism by which antioxidants may offer a clinical benefit in acute coronary syndrome and restenosis.
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39
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Ostrovidov S, Franck P, Joseph D, Martarello L, Kirsch G, Belleville F, Nabet P, Dousset B. Screening of new antioxidant molecules using flow cytometry. J Med Chem 2000; 43:1762-9. [PMID: 10794693 DOI: 10.1021/jm991019j] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a flow cytometry technique to evaluate the antioxidative properties of molecules on living cells, using a stable murine-murine hybridoma (Mark 3) cell line routinely cultured. Using this technique, intracellular superoxide anions and peroxides were evaluated with dihydrorhodamine (DHR-123) and dichlorofluorescein diacetate (DCFH-DA), respectively. When cells were first incubated for 10 min with either H(2)O(2) or the xanthine (X)/xanthine oxidase (XO) system, this flow cytometric technique was capable of evaluating the oxidative stress on cells. Twenty-one new analogues of ellipticine were synthesized and tested for their antioxidative properties compared to vitamin E and Ebselen used as references. A good statistical reflection of the antioxidative activities of these molecules was achieved by analyzing 35 000 cells in each experiment. Among them, the selenated molecule 18 was found to be 10 times more active than Ebselen but 10 000 times less active than vitamin E. Moreover, eight compounds showed glutathione peroxidase-like activities.
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Affiliation(s)
- S Ostrovidov
- Laboratory of Medical Biochemistry, School of Medicine, CHU, C.O. Box 34, 54035 Nancy Cedex, France
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Noguchi N, Nishino K, Niki E. Antioxidant action of the antihypertensive drug, carvedilol, against lipid peroxidation. Biochem Pharmacol 2000; 59:1069-76. [PMID: 10704936 DOI: 10.1016/s0006-2952(99)00417-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The action of carvedilol, a vasodilating, beta-adrenoceptor blocking agent, against lipid peroxidation has been the subject of many studies, but the results reported thus far are contradictory. In an attempt to define the antioxidant mechanism of carvedilol against lipid peroxidation, the dynamics of the action of carvedilol were studied in several oxidation systems. We investigated the reactivity of carvedilol toward radicals and its inhibitory effect on lipid peroxidation induced by several kinds of initiating species such as azo compounds and metal ions in solution, micelles, membranes, and low-density lipoprotein. Carvedilol exerted poor reactivity toward phenoxyl, alkoxyl, and peroxyl radicals in acetonitrile solution nor did it show an appreciable antioxidant effect against either the peroxyl radical-induced oxidation of methyl linoleate in acetonitrile or against phosphatidylcholine liposomal membranes in aqueous suspension. Carvedilol completely inhibited the ferric ion-induced oxidation of methyl linoleate micelles by sequestering ferric ions, but not by reducing hydroperoxide. It was shown that carvedilol enhanced the oxidation of micelles induced by either methemoglobin or peroxyl radical. Carvedilol, which was added exogenously, did not suppress the oxidation of isolated low-density lipoprotein induced by peroxyl radical or cupric ion. These results show that carvedilol does not act as a radical-scavenging antioxidant, but that it does act most efficiently as an antioxidant against ferric ion-induced oxidation by sequestering ferric ion.
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Affiliation(s)
- N Noguchi
- Research Center for Advanced Science and Technology, University of Tokyo, Meguro, Tokyo, Japan.
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41
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Abstract
Stroke occurs due to haemorrhage or occlusive injury and results in ischaemia and reperfusion injury. A variety of destructive mechanisms are involved including oxygen radical generation, calcium overload, cytotoxicity and apoptosis as well as the generation of inflammatory mediators. Ebselen, 2-phenyl-1, 2-benzisoselenazol-3(2H)-one (PZ 51, DR3305), is a mimic of GSH peroxidase which also reacts with peroxynitrite and can inhibit enzymes such as lipoxygenases, NO synthases, NADPH oxidase, protein kinase C and H(+)/K(+)-ATPase. Ebselen is in a late stage of development for the treatment of stroke. The molecular actions of ebselen contribute to its anti-inflammatory and anti-oxidant properties, which have been demonstrated in a variety of in vivo models. Numerous in vitro experiments using isolated LDL, liposomes, microsomes, isolated cells and organs have established that ebselen protects against oxidative challenge. Unlike many inorganic and aliphatic selenium compounds, ebselen has low toxicity as metabolism of the compound does not liberate the selenium moiety, which remains within the ring structure. Subsequent metabolism involves methylation, glucuronidation and hydroxylation. Experimental studies in rats and dogs have revealed that ebselen is able to inhibit both vasospasm and tissue damage in stroke models, which correlates with its inhibitory effects on oxidative processes. Results from randomised, placebo-controlled, double-blind clinical studies on the neurological consequences of acute ischaemic stroke, subarachnoid haemorrhage and acute middle cerebral artery occlusion, have revealed that ebselen significantly enhances outcome in patients who have experienced occlusive cerebral ischaemia of limited duration. The benefit achieved with ebselen is closely related to the rapidity with which the treatment is initiated, following the onset of the stroke attack. Safety and tolerability are good and no adverse effects have become apparent. Ebselen is currently at the pre-registration stage for subarachnoid haemorrhage and stroke in Japan.
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Affiliation(s)
- M Parnham
- Institut für Physiologische Chemie I, Heinrich-Heine-Universität, Postfach 101007, D-40001, Düsseldorf, Germany.
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42
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Yu TW, Ong CN. Lag-time measurement of antioxidant capacity using myoglobin and 2, 2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid): rationale, application, and limitation. Anal Biochem 1999; 275:217-23. [PMID: 10552907 DOI: 10.1006/abio.1999.4314] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The application of a simple lag-time assay for antioxidant capacity using myoglobin and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) or ABTS has been studied for its general application conditions. In the presence of an antioxidant, the ABTS(*+) radical-cation-forming chromogenic reaction, catalyzed by myoglobin and initiated by hydrogen peroxide (H(2)O(2)), has a lag period, and its duration is linearly correlated to the concentration of that antioxidant. The high linearity between the lag time and the antioxidant concentration remained unchanged regardless of the assay conditions. It was also found that the linearity was better for antioxidants at lower concentrations. The change of assay condition could significantly affect the relative antioxidant value of a chemical to the standard (ascorbic acid), although not to a large extent. Most of antioxidants investigated were found suitable to be assayed using this method. Some antioxidants, e.g., genistein, however, were not, probably due to their low reactivity toward ferrylmyoglobin or ABTS(*+). In conclusion, the lag-time assay is a reliable method for measuring the antioxidant capacity, provided caution is taken for antioxidants that mainly act through lowering the rate of the chromogenic reaction.
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Affiliation(s)
- T W Yu
- Occupational and Family Medicine, Faculty of Medicine (MD3), National University of Singapore, 16 Medical Drive, Singapore, 117597.
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Abstract
The family of glutathione peroxidases comprises four distinct mammalian selenoproteins. The classical enzyme (cGPx) is ubiquitously distributed. According to animal, cell culture and inverse genetic studies, its primary function is to counteract oxidative attack. It is dispensible in unstressed animals, and accordingly ranks low in the hierarchy of glutathione peroxidases. The gastrointestinal isoenzyme (GI-GPx) is most related to cGPx and is exclusively expressed in the gastrointestinal tract. It might provide a barrier against hydroperoxides derived from the diet or from metabolism of ingested xenobiotics. The extreme stability in selenium deficiency ranks this glutathione peroxidase highest in the hierarchy of selenoproteins and points to a more vital function than that of cGPx. Plasma GPx (pGPx) behaves similar to cGPx in selenium deficiency. It is directed to extracellular compartments and is expressed in various tissues in contact with body fluids, e.g., kidney, ciliary body, and maternal/fetal interfaces. It has to be rated as an efficient extracellular antioxidant device, though with low capacity because of the limited extracellular content of potential thiol substrates. Phospholipid hydroperoxide glutathione peroxidase (PHGPx), originally presumed to be a universal antioxidant enzyme protecting membrane lipids, appears to have adopted a variety of specific roles like silencing lipoxygenases and becoming an enzymatically inactive structural component of the mitochondrial capsule during sperm maturation. Thus, all individual isoenzymes are efficient peroxidases in principle, but beyond their mere antioxidant potential may exert cell- and tissue-specific roles in metabolic regulation, as is evident for PHGPx and may be expected for others.
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Unlüçerçi YM, Bulut R, Bekpinar S, Kuntsal L. Ebselen as protection against ethanol-induced toxicity in rat stomach. J Trace Elem Med Biol 1999; 13:170-5. [PMID: 10612080 DOI: 10.1016/s0946-672x(99)80007-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The mucosal protective effect of ebselen was examined in an ethanol-induced rat gastric lesion model. Examination of gastric tissue samples by light microscopy showed that i.g. exposure to 50% ethanol induced gastric injury, which was more prominent in female rats. Ethanol did not effect the gastric acid secretion examined by means of H(+)-K+ATPase, the increment of which might be harmful in the stomach. But ebselen with or without ethanol kept H(+)-K+ATPase below control levels. Gastric alcohol dehydrogenase (ADH) was mainly responsible for oxidation of ethanol in the stomach before it enters the bloodstream. I.g. ethanol exposure inhibited the ADH activity but ebselen eliminated the ethanol-induced inhibition of this enzyme. Therefore, ebselen exhibited a beneficial effect by increasing the gastric ethanol metabolism and by ameliorating the possible tissue toxicity of ethanol. Consistently, we also found that ebselen diminished the blood ethanol level. A gender difference in the blood ethanol levels existed following the same dose of ethanol but there was no difference in ADH activity. Histologically, mucosal injury following ebselen exposure together with ethanol was less severe compared with ethanol treatment alone. We concluded that the decrease in ethanol-induced mucosal injury following ebselen may have contributed to the inhibition of H(+)-K+ATPase and the activation of ADH by ebselen.
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Affiliation(s)
- Y M Unlüçerçi
- Department of Biochemistry, Istanbul Faculty of Medicine, University of Istanbul, Turkey
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Korytowski W, Wrona M, Girotti AW. Radiolabeled cholesterol as a reporter for assessing one-electron turnover of lipid hydroperoxides. Anal Biochem 1999; 270:123-32. [PMID: 10328773 DOI: 10.1006/abio.1999.4070] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel approach for assessing the peroxidative chain initiation potency of lipid hydroperoxides has been developed, which involves use of 14C-labeled cholesterol (Ch) as a "reporter" lipid. Unilamellar liposomes containing 1-palmitoyl-2-oleoyl-phosphatidylcholine, [14C]Ch, and 3beta-hydroxy-5alpha-cholest-6-ene-5-hydroperoxide (5alpha-OOH) or 3beta-hydroxycholest-5-ene-7alpha-hydroperoxide (7alpha-OOH) [100:75:5, mol/mol] were used as a test system. Liposomes incubated in the presence of ascorbate and a lipophilic iron complex were analyzed for radiolabeled oxidation products/intermediates (ChOX) by means of silica gel high-performance thin layer chromatography with phosphorimaging detection. The following ChOX were detected and quantified: 7alpha-OOH, 7beta-OOH, 7alpha-OH, 7beta-OH, and 5, 6-epoxide. Total ChOX yield increased in essentially the same time- and [iron]-dependent fashion for initiating 5alpha-OOH and 7alpha-OOH. The initial rate of [14C]7alphabeta-OH formation was greatly diminished when GSH and ebselen (a selenoperoxidase mimetic) were present, consistent with the attenuation of one-electron peroxide turnover. [14C]Ch-labeled L1210 cells also accumulated ChOX when incubated with 5alpha-OOH-containing liposomes. The rate of accumulation was substantially greater for Se-deficient than Se-sufficient cells, indicating that peroxide-induced chain reactions were modulated by selenoperoxidase action. These results illustrate the advantages of the new approach for highly sensitive in situ monitoring of cellular peroxidative damage.
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Affiliation(s)
- W Korytowski
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Abstract
Vitamin E acts as an important antioxidant against oxidative modification of low density lipoprotein (LDL) which is accepted as an initial event in the pathogenesis of atherosclerosis. In spite of the numerous studies and reports, the action and role of vitamin E have not been fully elucidated yet. In this brief overview, the dynamics of action of vitamin E as an antioxidant have been discussed and it is emphasized that the total antioxidant potency is determined by the relative importance of many competing reactions which is determined by the reactivities and concentrations of substrates, radicals and antioxidant and by physical factors of the environment.
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Affiliation(s)
- N Noguchi
- Research Center for Advanced Science and Technology, University of Tokyo, Meguro, Japan
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Tubaro F, Ghiselli A, Rapuzzi P, Maiorino M, Ursini F. Analysis of plasma antioxidant capacity by competition kinetics. Free Radic Biol Med 1998; 24:1228-34. [PMID: 9626578 DOI: 10.1016/s0891-5849(97)00436-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A competition kinetics procedure for measuring plasma antioxidant capacity is described. This procedure is based on the "crocin bleaching test" (Bors, W., et al. Biochim. Biophys. Acta 796:312-319; 1984) modified for analyzing the antioxidant capacity of complex mixtures (Tubaro, F., et al. J. Am. Oil Chem. Soc. 73:173-179; 1996). The information produced by this test is similar to that of the popular "total radical trapping antioxidant potential" (TRAP) analysis. However, the adopted kinetic approach is, in principle, more precise, taking into account both the concentration of antioxidants and their rate constant for the reaction with peroxy radical, which is overlooked in TRAP tests, as implied by the theory of the approach and confirmed by dynamic modeling. The kinetic analysis has also the advantage of accounting for the average between antioxidant effect (reduction of peroxy radicals) and possible prooxidant effect (oxidation by the radical of the antioxidant of the target supposed to be protected) if any. Thus, the result of this analysis provides a more precise evaluation of the efficiency of antioxidant defense. The intraassay variation resulted in less than 8% and, in young healthy subjects, the plasma antioxidant capacity, expressed as mM equivalents of a reference antioxidant (Trolox C), gave 1.59 +/- 0.28. The validated procedure has been used to show that plasma antioxidant capacity is deeply influenced by the consumption of wine.
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Affiliation(s)
- F Tubaro
- Department of Chemical Sciences and Technology, University of Udine, Italy
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Husain K, Morris C, Whitworth C, Trammell GL, Rybak LP, Somani SM. Protection by ebselen against cisplatin-induced nephrotoxicity: antioxidant system. Mol Cell Biochem 1998; 178:127-33. [PMID: 9546591 DOI: 10.1023/a:1006889427520] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This study was designed to investigate the cisplatin-induced alteration in renal antioxidant system and the nephroprotection with ebselen. Male Wistar rats were injected with (1) vehicle control; (2) cisplatin; (3) ebselen; and (4) cisplatin plus ebselen. Rats were sacrificed three days post-treatment and plasma as well as kidney were isolated and analyzed. Plasma creatinine increased 598% following cisplatin administration alone which decreased by 158% with ebselen pretreatment. Cisplatin-treated rats showed a depletion of renal glutathione (GSH) levels (52% of control), while cisplatin plus ebselen injected rats had GSH values close to the controls. Antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities decreased 38, 75 and 62% of control, respectively, and malondialdehyde (MDA) levels increased 174% of control following cisplatin administration, which were restored to control levels after ebselen treatment. The renal platinum level did not significantly change with ebselen pretreatment. This study suggests that the protection offered by ebselen against cisplatin-induced nephrotoxicity is partly related to the sparing of antioxidant system.
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Affiliation(s)
- K Husain
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794, USA
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Brown AJ, Leong SL, Dean RT, Jessup W. 7-Hydroperoxycholesterol and its products in oxidized low density lipoprotein and human atherosclerotic plaque. J Lipid Res 1997. [DOI: 10.1016/s0022-2275(20)37148-0] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Lass A, Witting P, Stocker R, Esterbauer H. Inhibition of copper- and peroxyl radical-induced LDL lipid oxidation by ebselen: antioxidant actions in addition to hydroperoxide-reducing activity. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1303:111-8. [PMID: 8856040 DOI: 10.1016/0005-2760(96)00088-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effects of ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) on human LDL lipid oxidation induced by different fluxes of aqueous peroxyl radicals and cupric ion (at a Cu2+:LDL ratio of 17:1) were investigated. Addition of ebselen to LDL oxidised with Cu2+ prolonged the duration of the lag-phase typical for this oxidising condition, with the increase being proportional to the square of the ebselen concentration. Ebselen also prevented the formation of lipid hydroperoxides and inhibited the consumption of endogenous antioxidants during the early period of Cu(2+)-induced oxidation, during which time the drug was converted stoichiometrically into ebselen oxide (2-phenyl-1,2-benzisoselenazol-3(2H)-one-Se-oxide). Ebselen oxide itself was antioxidant inactive. Ebselen also inhibited formation of lipid-hydroperoxides and spared alpha-tocopherol during the initial stages of LDL oxidation mediated by low-flux of aqueous peroxyl radicals, where a lag-phase was not observed. When a higher flux of aqueous peroxyl radicals was used, ebselen increased the observed inhibited phase of peroxidation in a dose-dependent manner, though less pronounced than its prolongating effect on the lag-phase of Cu(2+)-induced LDL lipid oxidation. Ebselen was also able to directly interact with Cu1+, alkyl peroxyl radicals and alpha-tocopheroxyl radicals, demonstrating that the drug has a number of potential antioxidant activities in addition to its well-known hydroperoxide-reducing activity. We conclude that the antioxidant activities of ebselen are complex and that their relative importance likely vary depending on the experimental system used.
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Affiliation(s)
- A Lass
- Institute of Biochemistry, University of Graz, Austria
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