Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extracts

Detalhes bibliográficos
Autor(a) principal: Hassan, Waseem
Data de Publicação: 2009
Tipo de documento: Tese
Idioma: eng
Título da fonte: Manancial - Repositório Digital da UFSM
Texto Completo: http://repositorio.ufsm.br/handle/1/23868
Resumo: -----
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spelling Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extractsOrganochalcogenspHAnti-oxidant activityThiolsCNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA-----Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPqAcademy of Sciences for Third World - TWASThis study provides experimental data about the anti-oxidant activity of diphenyl diselenide, diphenyl ditelluride, a novel organoselenium compound and ebselen under various pH conditions. Iron is more soluble at lower pH values; therefore we hypothesized that decreasing the environmental pH would lead to increased iron-mediated lipid peroxidation. Because of the pH dependency of iron redox cycling, pH and iron need to be well controlled and for the reason we tested a number of pH values (from 7.4 to 5.4) to get a closer idea about the role of iron under various pathological conditions. Acidosis increased rate of lipid peroxidation in the absence Fe (II) in rat tissue homogenates especially at pH 5.4. This higher extent of lipid peroxidation can be explained by; the mobilized iron which may come from reserves where it is weakly bound. Addition of iron (Fe) chelator desferoxamine (DFO) to reaction medium completely inhibited the peroxidation processes at all studied pH values including acidic values (5.8-5.4). In the presence of Fe (II) acidosis also enhanced detrimental effect of Fe (II) especially at pH (6.4-5.4). All Tested compounds significantly protected lipid peroxidation at all studied pH values, except ebselen which offered only a small statistically non-significant protection. The highest antioxidant potency was observed for diphenyl ditelluride. These differences in potencies were explained by the mode of action of these compounds using their catalytic anti-oxidant cycles. We have also tested the thiol oxidase activity of diphenyl ditelluride as thiol oxidation by diphenyl ditelluride is a favorable reaction and may be responsible for alteration in regulatory or signaling pathways. We have measured rate constants for reactions of diphenyl ditelluride with cysteine, dimercaptosuccinic acid, glutathione and dithiothreitol in phosphate buffer. The relative reactivities of the different thiols with diphenyl ditelluride were independent of the pKa of the thiol group, such that at pH 7.4, cysteine AND dithiothreitol were the most reactive and low reactivity was observed with glutathione and dimercaptosuccinic acid. The reactivity of diphenyl ditelluride was not modified by change in pH. Rate of oxidation increased with increasing pH for all thiols except dimercaptosuccinic acid, where the rate of oxidation was faster at low pH. This study provides in-vitro evidence for acidosis induced oxidative stress and in rat tissues and potential anti-oxidant action of Our observations will be of importance in our understanding of pathologies which are associated with low tissue pH. These studies confirm that organochalcogens are redox active within physiologically relevant potential range. The implication from these results for a biological system is that these compounds may react with thiols on the basis of their chemical reactivity. If it is selective, accessibility or other molecular features may be more important determinants. Furthermore other aspect that deserve investigation is to determine a possible relationship between thiol-peroxidase activity of these compounds with the capacity of catalyzing thiol/sulfide exchange, and how these two chemical properties of selenide/tellurides correlates with their toxicological and pharmacological effects.Universidade Federal de Santa MariaBrasilBioquímicaUFSMPrograma de Pós-Graduação em Ciências Biológicas: Bioquímica ToxicológicaCentro de Ciências Naturais e ExatasRocha, João Batista Teixeira dahttp://lattes.cnpq.br/3935055744673018Santos, Jose Eduardo Tanus dosKlamt, FábioBem, Andreza Fabro dePosser, ThaisHassan, Waseem2022-03-24T10:47:14Z2022-03-24T10:47:14Z2009info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttp://repositorio.ufsm.br/handle/1/23868engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSM2022-06-13T18:26:13Zoai:repositorio.ufsm.br:1/23868Biblioteca Digital de Teses e Dissertaçõeshttps://repositorio.ufsm.br/ONGhttps://repositorio.ufsm.br/oai/requestatendimento.sib@ufsm.br||tedebc@gmail.comopendoar:2022-06-13T18:26:13Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false
dc.title.none.fl_str_mv Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extracts
title Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extracts
spellingShingle Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extracts
Hassan, Waseem
Organochalcogens
pH
Anti-oxidant activity
Thiols
CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA
title_short Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extracts
title_full Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extracts
title_fullStr Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extracts
title_full_unstemmed Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extracts
title_sort Influence of pH on the reactivity of organochalcogens with thiols of biological significance and anti-oxidant potential In rat’s tissue and phospholipid extracts
author Hassan, Waseem
author_facet Hassan, Waseem
author_role author
dc.contributor.none.fl_str_mv Rocha, João Batista Teixeira da
http://lattes.cnpq.br/3935055744673018
Santos, Jose Eduardo Tanus dos
Klamt, Fábio
Bem, Andreza Fabro de
Posser, Thais
dc.contributor.author.fl_str_mv Hassan, Waseem
dc.subject.por.fl_str_mv Organochalcogens
pH
Anti-oxidant activity
Thiols
CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA
topic Organochalcogens
pH
Anti-oxidant activity
Thiols
CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA
description -----
publishDate 2009
dc.date.none.fl_str_mv 2009
2022-03-24T10:47:14Z
2022-03-24T10:47:14Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/doctoralThesis
format doctoralThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://repositorio.ufsm.br/handle/1/23868
url http://repositorio.ufsm.br/handle/1/23868
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Universidade Federal de Santa Maria
Brasil
Bioquímica
UFSM
Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica
Centro de Ciências Naturais e Exatas
publisher.none.fl_str_mv Universidade Federal de Santa Maria
Brasil
Bioquímica
UFSM
Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica
Centro de Ciências Naturais e Exatas
dc.source.none.fl_str_mv reponame:Manancial - Repositório Digital da UFSM
instname:Universidade Federal de Santa Maria (UFSM)
instacron:UFSM
instname_str Universidade Federal de Santa Maria (UFSM)
instacron_str UFSM
institution UFSM
reponame_str Manancial - Repositório Digital da UFSM
collection Manancial - Repositório Digital da UFSM
repository.name.fl_str_mv Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)
repository.mail.fl_str_mv atendimento.sib@ufsm.br||tedebc@gmail.com
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