title: Oxalate modulates thiobarbituric acid reactive species (TBARS) production in supernatants of homogenates from rat brain, liver and kidney: effect of diphenyl diselenide and diphenyl ditelluride.
abstract: The aim of this paper was to investigate the mechanism(s) involved in the sodium oxalate pro-oxidative activity in vitro and the potential protection by diphenyl diselenide ((PhSe)(2)) and diphenyl ditelluride ((PhTe)(2)) using supernatants of homogenates from brain, liver and kidney. Oxalate causes a significant increase in the TBARS (thiobarbituric acid reactive species) production up to 4mmol/l and it had antioxidant activity from 8 to 16mmol/l in the brain and liver. Oxalate had no effect in kidney homogenates. The difference among tissues may be related to the formation of insoluble crystal of oxalate in kidney, but not in liver and brain homogenates. (PhSe)(2) and (PhTe)(2) reduced both basal and oxalate-induced TBARS in rat brain homogenates, whereas in liver homogenates they were antioxidant only on oxalate-induced TBARS production. (PhSe)(2) showed a modest effect on renal TBARS production, whereas (PhTe)(2) did not modulate TBARS in kidney preparations. Oxalate at 2mmol/l did not change deoxyribose degradation induced by Fe(2+) plus H(2)O(2), whereas at 20mmol/l it significantly prevents its degradation. Oxalate (up to 4mmol/l) did not alter iron (10micromol/l)-induced TBARS production in the brain preparations, whereas at 8mmol/l onwards it prevents iron effect. In liver preparations, oxalate amplifies iron pro-oxidant activity up to 4mmol/l, preventing iron-induced TBARS production at 16mmol/l onwards. These results support the antioxidant effect of organochalcogens against oxalate-induced TBARS production. In addition, our results suggest that oxalate pro- and antioxidant activity in vitro could be related to its interactions with iron ions.
authors.affiliation: Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Campus UFSM, Santa Maria, RS 97105-900, Brazil.
authors.forename: Robson Luiz
authors.initials: RL
authors.lastname: Puntel
authors.forename: Daniel Henrique
authors.initials: DH
authors.lastname: Roos
authors.forename: Márcio Weber
authors.initials: MW
authors.lastname: Paixão
authors.forename: Antônio Luiz
authors.initials: AL
authors.lastname: Braga
authors.forename: Gilson
authors.initials: G
authors.lastname: Zeni
authors.forename: Cristina Wayne
authors.initials: CW
authors.lastname: Nogueira
authors.forename: Joao Batista Teixeira
authors.initials: JB
authors.lastname: Rocha
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001555:Benzene Derivatives / Q000494:pharmacology; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D003855:Deoxyribose / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004336:Drug Antagonism; D066298:In Vitro Techniques; D007501:Iron / Q000378:metabolism / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009942:Organometallic Compounds / Q000494:pharmacology*; D016566:Organoselenium Compounds / Q000494:pharmacology; D010070:Oxalates / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D001555:Benzene Derivatives; D009942:Organometallic Compounds; D016566:Organoselenium Compounds; D010070:Oxalates; D017392:Thiobarbituric Acid Reactive Substances; C434247:diphenylditelluride; C061132:diphenyldiselenide; D003855:Deoxyribose; D007501:Iron