SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Belló-Klein,A.; Oliveira,A.R.; Miranda,M.F.S.; Irigoyen,M.C.; Homem-de-Bittencourt Jr.,P.I.; Llesuy,S.; Belló,A.A..

Hydrogen peroxide (H2O2) perfused into the aorta of the isolated rat heart induces a positive inotropic effect, with cardiac arrhythmia such as extrasystolic potentiation or cardiac contractures, depending on the dose. The last effect is similar to the "stone heart" observed in reperfusion injury and may be ascribed to lipoperoxidation (LPO) of the membrane lipids, to protein damage, to reduction of the ATP level, to enzymatic alterations and to cardioactive compounds liberated by LPO. These effects may result in calcium overload of the cardiac fibers and contracture ("stone heart"). Hearts from male Wistar rats (300-350 g) were perfused at 31oC with Tyrode, 0.2 mM trolox C, 256 mM H2O2 or trolox C + H2O2. Cardiac contractures (baseline elevation of the...

Application of various antioxidants in the treatment of influenza

Palavras-chave: Trolox C; "stone heart"; Free radicals; Hydrogen peroxide.

Ano: 1997

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997001100013

Dolganova,A.; Sharonov,B.P..

We determined the effect of the antioxidants superoxide dismutase, desferrioxamine and allopurinol on the survival of male CBA mice infected intranasally with 2-5 LD50 lung influenza virus A/Aichi/2/68. Survival for at least 20 days was observed for 45% of the mice that received 1000 U/day superoxide dismutase prepared from red blood cells on days 5, 6, 7 and 8 after infection, and 75% survival was observed for mice that received the same dose on days 4, 5, 6, 7 and 8. Desferrioxamine, 25 mg/kg per day and 100 mg/kg per day injected subcutaneously, resulted in survival rates of 5 and 0%, respectively, compared to 10% survival observed for saline-injected controls. Allopurinol at doses of 5 to 50 mg/kg per day had no effect on mouse survival. These data...

Nonspecific blockade of vascular free radical signals by methylated arginine analogues

Palavras-chave: Free radicals; Influenza; Antioxidant; Desferrioxamine; Superoxide dismutase; Allopurinol.

Ano: 1997

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997001100012

Pedro,M.A.; Augusto,O.; Barbeiro,H.V.; Carvalho,M.H.C.; da-Luz,P.L.; Laurindo,F.R.M..

Methylated arginine analogues are often used as probes of the effect of nitric oxide; however, their specificity is unclear and seems to be frequently overestimated. This study analyzed the effects of NG-methyl-L-arginine (L-NMMA) on the endothelium-dependent release of vascular superoxide radicals triggered by increased flow. Plasma ascorbyl radical signals measured by direct electron paramagnetic resonance spectroscopy in 25 rabbits increased by 3.8 ± 0.7 nmol/l vs baseline (28.7 ± 1.4 nmol/l, P<0.001) in response to papaverine-induced flow increases of 121 ± 12%. In contrast, after similar papaverine-induced flow increases simultaneously with L-NMMA infusions, ascorbyl levels were not significantly changed compared to baseline. Similar results...

Zinc in the prevention of Fe2initiated lipid and protein oxidation

Palavras-chave: Free radicals; Arginine analogues; NG-methyl-L-arginine; NG-methyl-D-arginine; NG-nitro-L-arginine methyl ester.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000600004

ZAGO,M. PAOLA; VERSTRAETEN,SANDRA V.; OTEIZA,PATRICIA I..

In the present study we characterized the capacity of zinc to protect lipids and proteins from Fe2+-initiated oxidative damage. The effects of zinc on lipid oxidation were investigated in liposomes composed of brain phosphatidylcholine (PC) and phosphatidylserine (PS) at a molar relationship of 60:40 (PC:PS, 60:40). Lipid oxidation was evaluated as the oxidation of cis-parinaric acid or as the formation of 2-thiobarbituric acid-reactive substances (TBARS). Zinc protected liposomes from Fe2+ (2.5-50 muM)-supported lipid oxidation. However, zinc (50 muM) did not prevent the oxidative inactivation of glutamine synthelase and glucose 6-phosphate dehydrogenase when rat brain superntants were oxidized in the presence of 5 muM Fe2+ and 0.5 mM H2O2 .We also...

Tipo: Journal article

Palavras-chave: Aluminum; Catechins; Free radicals; Iron; Lipid peroxidation; Zinc.

Ano: 2000

URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200014

Nitric Oxide: Oxygen Radical Interactions in Atherosclerosis

Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma

RUBBO,HOMERO; BATTHYANY,CARLOS; RADI,RAFAEL.

Atherosclerosis is one of the most common diseases and the principal cause of death in western civilization. The pathogenesis of this disease can be explained on the basis of the oxidative-modification hypothesis, which proposes that low-density lipoprotein (LDL) oxidation represents a key early event. Nitric oxide (.NO) regulates critical lipid membrane and lipoprotein oxidation events by a) contributing to the formation of more potent secondary oxidants from superoxide (i.e.: peroxynitrite), and b) its antioxidant properties through termination reactions with lipid radicals to possibly less reactive secondary nitrogen-containing products (LONO, LOONO). Relative rates of production and steady state concentrations of superoxide and .NO and cellular sites...

Tipo: Journal article

Palavras-chave: Antioxidants; Free radicals; Lipid oxidation; Low density lipoprotein oxidation; Nitric oxide; Peroxynitrite.

Ano: 2000

URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200017

LOTITO,SILVINA B; FRAGA,CESAR G.

We evaluated the interaction between ascorbic acid (AA) and (+)-catechin (CTCH) in potassium phosphate solution, pH 7.4 (PPS) and in human plasma. In both systems, the oxidation was started by adding 2,2-azobis-(2-amidinopropane) clorhidrate (AAPH). The concentrations of AA and CTCH were determined by HPLC using electrochemical detection. In PPS, CTCH was oxidized by AAPH (50 muM), in either the absence or presence of different initial concentrations of AA (25-200 muM). In the presence of AA, CTCH depletion was delayed, an effect that was dependent upon the initial concentration of AA. When 100 muM AA was added after the oxidation had begun, CTCH depletion was arrested for 30 min. The kinetics of AA oxidation by AAPH was also characterized in PPS. AA (100...

Tipo: Journal article

Palavras-chave: Catechins; Antioxidants; Free radicals; Procyanidins.

Ano: 2000

URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200015

Alternative mitochondrial functions in cell physiopathology: beyond ATP production

Kowaltowski,A.J..

It is well known that mitochondria are the main site for ATP generation within most tissues. However, mitochondria also participate in a surprising number of alternative activities, including intracellular Ca2+ regulation, thermogenesis and the control of apoptosis. In addition, mitochondria are the main cellular generators of reactive oxygen species, and may trigger necrotic cell death under conditions of oxidative stress. This review concentrates on these alternative mitochondrial functions, and their role in cell physiopathology.

Antioxidant properties of natural compounds used in popular medicine for gastric ulcers

Palavras-chave: Mitochondrial permeability transition; Uncoupling proteins; Alternative oxidase; Cardioprotection; Free radicals; Aging.

Ano: 2000

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000000200014

Repetto,M.G.; Llesuy,S.F..

There is evidence concerning the participation of reactive oxygen species in the etiology and physiopathology of human diseases, such as neurodegenerative disorders, inflammation, viral infections, autoimmune pathologies, and digestive system disorders such as gastrointestinal inflammation and gastric ulcer. The role of these reactive oxygen species in several diseases and the potential antioxidant protective effect of natural compounds on affected tissues are topics of high current interest. To consider a natural compound or a drug as an antioxidant substance it is necessary to investigate its antioxidant properties in vitro and then to evaluate its antioxidant functions in biological systems. In this review article, we shall consider the role of natural...

Membrane effects of Cocoa Procyanidins in Liposomes and Jurkat T Cells

Palavras-chave: Antioxidant; Free radicals; Natural antioxidants; Gastric ulcers; Artemisia douglasiana Besser; Dehydroleucodine.

Ano: 2002

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000500003

VERSTRAETEN,SANDRA V.; OTEIZA,PATRICIA I.; FRAGA,CÉSAR G..

We investigated the effects of the interaction between flavanols and related procyanidins (dimer to hexamer) with both cell and synthetic membranes, on bilayer fluidity and susceptibility to oxidation. Cocoa derived dimers (0.05 to 1 µg/ml) protected Jurkat T cells from AMVN-mediated oxidation and increased plasma membrane fluidity. These effects occurred in a concentration- and chain length-dependent manner. In liposomes, procyanidins prevented the Fe2+-induced permeabilization of the membrane. Together, these results support the hypothesis that procyanidins could interact with the polar headgroup of lipids, increasing membrane fluidity and also, preventing the access of molecules that could affect membrane integrity

Tipo: Journal article

Palavras-chave: Epicatechin; Free radicals; Lipid oxidation; Membrane fluidity; Membrane permeability; Procyanidins.

Ano: 2004

URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000200016

Lipid peroxidation and total radical-trapping potential of the lungs of rats submitted to chronic and sub-chronic stress

Torres,R.L.; Torres,I.L.S.; Gamaro,G.D.; Fontella,F.U.; Silveira,P.P.; Moreira,J.S.R.; Lacerda,M.; Amoretti,J.R.; Rech,D.; Dalmaz,C.; Belló,A.A..

Exposure to stress induces a cluster of physiological and behavioral changes in an effort to maintain the homeostasis of the organism. Long-term exposure to stress, however, has detrimental effects on several cell functions such as the impairment of antioxidant defenses leading to oxidative damage. Oxidative stress is a central feature of many diseases. The lungs are particularly susceptible to lesions by free radicals and pulmonary antioxidant defenses are extensively distributed and include both enzymatic and non-enzymatic systems. The aim of the present study was to determine lipid peroxidation and total radical-trapping potential (TRAP) changes in lungs of rats submitted to different models of chronic stress. Adult male Wistar rats weighing 180-230 g...

Ginseng administration protects skeletal muscle from oxidative stress induced by acute exercise in rats

Palavras-chave: Stress; TBARS; TRAP; Free radicals; Lungs; Oxidative stress.

Ano: 2004

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000200004

Voces,J.; Cabral de Oliveira,A.C.; Prieto,J.G.; Vila,L.; Perez,A.C.; Duarte,I.D.G.; Alvarez,A.I..

Enzymatic activity was analyzed in the soleus, gastrocnemius (red and white) and plantaris muscles of acutely exercised rats after long-term administration of Panax ginseng extract in order to evaluate the protective role of ginseng against skeletal muscle oxidation. Ginseng extract (3, 10, 100, or 500 mg/kg) was administered orally for three months to male Wistar rats weighing 200 ± 50 g before exercise and to non-exercised rats (N = 8/group). The results showed a membrane stabilizing capacity of the extract since mitochondrial function measured on the basis of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities was reduced, on average, by 20% (P < 0.05) after exercise but the activities remained unchanged in animals treated with a ginseng...

Mitochondrial K+ transport and cardiac protection during ischemia/reperfusion

Palavras-chave: Panax ginseng; Exercise; Free radicals; Lipid peroxidation; Glutathione status; Mitochondria.

Ano: 2004

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004001200012

Carreira,R.S.; Facundo,H.T.F.; Kowaltowski,A.J..

Mitochondrial ion transport, oxidative phosphorylation, redox balance, and physical integrity are key factors in tissue survival following potentially damaging conditions such as ischemia/reperfusion. Recent research has demonstrated that pharmacologically activated inner mitochondrial membrane ATP-sensitive K+ channels (mitoK ATP) are strongly cardioprotective under these conditions. Furthermore, mitoK ATP are physiologically activated during ischemic preconditioning, a procedure which protects against ischemic damage. In this review, we discuss mechanisms by which mitoK ATP may be activated during preconditioning and the mitochondrial and cellular consequences of this activation, focusing on end-effects which may promote ischemic protection. These...

Protein 3-nitrotyrosine formation during Trypanosoma cruzi infection in mice

Palavras-chave: Mitochondria; Potassium; Calcium; Free radicals; Heart; Ischemia.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000300004

Naviliat,M.; Gualco,G.; Cayota,A.; Radi,R..

Nitric oxide (·NO) is a diffusible messenger implicated in Trypanosoma cruzi resistance. Excess production of ·NO and oxidants leads to the generation of nitrogen dioxide (·NO2), a strong nitrating agent. Tyrosine nitration is a post-translational modification resulting from the addition of a nitro (-NO2) group to the ortho-position of tyrosine residues. Detection of protein 3-nitrotyrosine is regarded as a marker of nitro-oxidative stress and is observed in inflammatory processes. The formation and role of nitrating species in the control and myocardiopathy of T. cruzi infection remain to be studied. We investigated the levels of ·NO and protein 3-nitrotyrosine in the plasma of C3H and BALB/c mice and pharmacologically modulated their production during...

Glutathione and the redox control system trypanothione/trypanothione reductase are involved in the protection of Leishmania spp. against nitrosothiol-induced cytotoxicity

Palavras-chave: Peroxynitrite; Nitric oxide; Nitrotyrosine; Free radicals; Trypanosoma cruzi; Chagas' disease.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005001200011

Romão,P.R.T.; Tovar,J.; Fonseca,S.G.; Moraes,R.H.; Cruz,A.K.; Hothersall,J.S.; Noronha-Dutra,A.A.; Ferreira,S.H.; Cunha,F.Q..

Glutathione is the major intracellular antioxidant thiol protecting mammalian cells against oxidative stress induced by oxygen- and nitrogen-derived reactive species. In trypanosomes and leishmanias, trypanothione plays a central role in parasite protection against mammalian host defence systems by recycling trypanothione disulphide by the enzyme trypanothione reductase. Although Kinetoplastida parasites lack glutathione reductase, they maintain significant levels of glutathione. The aim of this study was to use Leishmania donovani trypanothione reductase gene mutant clones and different Leishmania species to examine the role of these two individual thiol systems in the protection mechanism against S-nitroso-N-acetyl-D,L-penicillamine (SNAP), a...

Antioxidant activity of extract from Polygonum cuspidatum

Palavras-chave: Leishmania; Glutathione; Trypanothione; Trypanothione reductase; Nitric oxide; Free radicals.

Ano: 2006

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006000300006

High susceptibility of activated lymphocytes to oxidative stress-induced cell death

HSU,CHIN-YUAN; CHAN,YU-PEI; CHANG,JELI.

Numerous diseases are induced by free radicals via lipid peroxidation, protein peroxidation and DNA damage. It has been known that a variety of plant extracts have antioxidant activities to scavenge free radicals. Whether Polygonum cuspidatum Sieb. et Zuce has antioxidant activity is unknown. In this study, dried roots of Polygonum cuspidatum were extracted by ethanol and the extract was lyophilized. Free radical scavenging assays, superoxide radical scavenging assays, lipid peroxidation assays and hydroxyl radical-induced DNA strand scission assays were employed to study antioxidant activities. The results indicate that the IC50 value oí Polygonum cuspidatum extract is 110 µg/ml in free radical scavenging assays, 3.2 µg/ml in superoxide radical scavenging...

Tipo: Journal article

Palavras-chave: Antioxidant activity; Free radicals; Phenolics; Lipid peroxidation; DNA damage Polygonum cuspidatum.

Ano: 2007

URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602007000100002

Anais da ABC (AABC)

Degasperi,Giovanna R.; Castilho,Roger F.; Vercesi,Anibal E..

The present study provides evidence that activated spleen lymphocytes from Walker 256 tumor bearing rats are more susceptible than controls to tert-butyl hydroperoxide (t-BOOH)-induced necrotic cell death in vitro. The iron chelator and antioxidant deferoxamine, the intracellular Ca2+ chelator BAPTA, the L-type Ca2+ channel antagonist nifedipine or the mitochondrial permeability transition inhibitor cyclosporin A, but not the calcineurin inhibitor FK-506, render control and activated lymphocytes equally resistant to the toxic effects of t-BOOH. Incubation of activated lymphocytes in the presence of t-BOOH resulted in a cyclosporin A-sensitive decrease in mitochondrial membrane potential. These results indicate that the higher cytosolic Ca2+ level in...

Enhanced response of the fricke solution doped with hematoporphyrin under X-rays irradiation

Palavras-chave: Cell death; Free radicals; Immune response; Lymphopenia; Mitochondrial permeability transition; Spleen lymphocyte.

Ano: 2008

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652008000100009

BABT

Austerlitz,Carlos; Souza,Vivianne Lúcia Bormann de; Campos,Diana Maria Tavares; Kurachi,Cristina; Bagnato,Vanderley; Sibata,Cláudio.

The vials filled with Fricke solutions were doped with increasing concentrations of Photogem®, used in photodynamic therapy. These vials were then irradiated with low-energy X-rays with doses ranging from 5 to 20 Gy. The conventional Fricke solution was also irradiated with the same doses. The concentration of ferric ions for the Fricke and doped-Fricke irradiated solutions were measured in a spectrophotometer at 220 to 340 nm. The results showed that there was an enhancement in the response of the doped-Fricke solution, which was proportional to the concentration of the photosensitizer. The use of such procedure for studying the radiosensitizing property of photosensitizers based on the production of free radicals is also discussed.

Superoxide dismutase and catalase: tissue activities and relation with age in the long-lived species Margaritifera margaritifera

Palavras-chave: Photodynamic therapy; Hematoporphyrin; Fricke dosimeter; Free radicals.

Ano: 2008

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000200006

FERNÁNDEZ,CARLOS; SAN MIGUEL,EDUARDO; FERNÁNDEZ-BRIERA,ALMUDENA.

Free radicals are extremely reactive and produce damage and modify cell functions. Furthermore, superoxide dismutase and catalase are believed to play a key role in the enzymatic defence of the cells. Indeed, some authors have argued that reduced free-radical damage could explain increased longevity. Margaritifera margaritifera is one of the longest-lived animals in the world (up to 100-200 years). Furthermore, this organism may serve as a useful model for gerontologists interested in exploring the mechanisms that promote long life and the slowing of senescence. The present study estimated for the first time individual enzymatic activity for superoxide dismutase isozymes (Cu,Zn-SOD and Mn-SOD) and catalase in tissue preparations of gills, digestive glands...

Tipo: Journal article

Palavras-chave: Margaritifera margaritifera; Free radicals; Aging; Superoxide dismutase; Catalase.

Ano: 2009

URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602009000100006

Biological effects of an aqueous extract of Salix alba on the survival of Escherichia coli AB1157 cultures submitted to the action of stannous chloride

SOUZA,RAPHAEL S S; ALMEIDA,MARCELA C; MANOEL,CRISTIANO V; SANTOS-FILHO,SEBASTIÃO D; FONSECA,ADENILSON S; FILHO,MARIO BERNARDO.

Stannous chloride (SnC12) is used in nuclear medicine as a reducing agent to obtain technetium-99m-radiopharmaceuticals. It have been reported that natural products might reduce the genotoxic and cytotoxic effects related to SnC12. This work evaluated the biological effects of an aqueous extract of Salix alba on the survival of Escherichia coli (E. coli) AB1157 (wild type) cultures submitted to the action of SnC12. E. coli AB1157 cultures (exponential growth phase) were collected by centrifugation, washed and resuspended in 0.9%NaCl. Samples were incubated in water bath shaker with: (a) SnC12 (25mg/ml), (b)Salix alba extract(11.6mg/ml) and (c)SnC12(25mg/ml) + Salix alba extract (11.6mg/ml). Incubation with 0.9% NaCl was also carried out (control). At 60...

Tipo: Journal article

Palavras-chave: Escherichia coli; Free radicals; Salix alba; Stannous chloride.

Ano: 2009

URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602009000200008

Salacia campestris root bark extract: peroxidase inhibition, antioxidant and antiradical profile

BJPS

Vellosa,José Carlos Rebuglio; Khalil,Najeh Maissar; Gutierres,Vânia Ortega; Santos,Vânia Aparecida de Freitas Formenton Macedo dos; Furlan,Maysa; Brunetti,Iguatemy Lourenço; Oliveira,Olga Maria Mascarenhas de Faria.

Reactive oxygen species (ROS) and free radical species have been implicated in initiating or accompanying many diseases in living organisms; there is thus, a continual need for antioxidants molecules to inactivate ROS/free radicals. Many studies of plants crude extracts have demonstrated free-radical scavenging and antioxidant action. Salacia species have long been used, in several countries, as traditional medicines against certain diseases and for their anti-inflammatory properties. In this study, Salacia campestris Walp (Hippocrateaceae) root bark ethanol extract (ScEtOH) was assessed for its ability to scavenge free radicals and reactive oxygen species; the results were expressed as percentage inhibition of the active species. ScEtOH was efficient...