The combined effect of copper and low pH on antioxidant defenses and biochemical parameters in neotropical fish pacu, Piaractus mesopotamicus (Holmberg, 1887)

Copper sulfate is widely used in aquaculture. Exposure to this compound can be harmful to fish, resulting in oxidative metabolism alterations and gill tissue damage. Pacu, Piaractus mesopotamicus, (wt = 43.4 +/- A 3.35 g) were distributed in experimental tanks (n = 10; 180 l) and exposed for 48 h to control (without copper addition), 0.4Cu (0.4 mg l(-1)), 0CupH (without copper addition, pH = 5.0) and 0.4CupH (0.4 mg l(-1), pH = 5.0). In liver and red muscle, the superoxide dismutase (SOD) was responsive to the increases in the aquatic copper. The plasmatic intermediary metabolites and hematological variables in the fish of group 0.4Cu were similar to those of the control group. Conversely, the exposure to 0.4CupH caused an increase in the plasmatic lactate, number of red blood cells (RBC) and hemoglobin (Hb). Plasmatic copper concentration [Cu(p)] increased in group 0.4Cu and 0.4CupH, which is higher in group 0.4CupH, suggests an effect of water pH on the absorbed copper. Exposure to 0.4Cu and 0.4CupH resulted in a reduction in the Na(+)/K(+)-ATPase activity and an increase in metallothionein (MT) in the gills. Exposure to 0CupH caused a decrease in glucose and pyruvate concentrations and an increase in RBC, Hb, and the branchial Na(+)/K(+)-ATPase activity. These responses suggest that the fish triggered mechanisms to revert the blood acidosis, save energy and increase the oxygen uptake. MT was an effective biomarker, responding to copper in different pHs and dissolved oxygen. Combined-factors caused more significant disturbance in the biomarkers than single-factors.

Aerobic exercise training improves the role of high-density lipoprotein antioxidant and reduces plasma lipid peroxidation in type 2 diabetes mellitus

In this study, we analyzed the effect of aerobic exercise training (AET) and of a single bout of exercise on plasma oxidative stress and on antioxidant defenses in type 2 diabetes mellitus (DM) and in healthy control subjects (C). DM and C did not differ regarding triglycerides, high-density lipoprotein cholesterol (HDL-c), insulin, and HOMA index at baseline and after AET. To measure the lag time for low-density lipoprotein (LDL) oxidation (LAG) and the maximal rate of conjugated diene formation (MCD), participants` plasma HDL(2) and HDL(3) were incubated with LDL from pooled healthy donors` plasma. In the presence of HDL(3), both LAG and MCD were similar in C and DM, but only in DM did AET improve LAG and reduce MCD. In the presence of HDL(2), the lower baseline LAG in DM equaled C after AET. MCD was unchanged in DM after AET, but was lower than C only after AET. Furthermore, after AET plasma thiobarbituric acid-reactive substances were reduced only in DM subjects. Despite not modifying the total plasma antioxidant status and serum paraoxonase-1 activity in both groups, AET lowered the plasma lipid peroxides, corrected the HDL(2), and improved the HDL(3) antioxidant efficiency in DM independent of the changes in blood glucose, insulin, and plasma HDL concentration and composition.

Avaliação da influência de substâncias fenólicas e carotenoides na anomalia do epicarpo da goiaba, "anelamento"

A anomalia do epicarpo da goiaba, comumente relatada por agricultores e técnicos como o "anelamento juvenil da goiaba", tem causado preocupação devido à desinformação sobre o assunto. O objetivo deste estudo foi analisar quimicamente as concentrações de substâncias fenólicas e carotenoides na região do epicarpo de goiabas afetadas pelo "anelamento", visando a caracterizar essa anomalia previamente relatada. Foram analisadas substâncias fenólicas (taninos, flavonas/flavonóis, antocianinas e fenóis totais) e carotenoides em epicarpos de frutos verdes e maduros de goiabeiras cv. Paluma, com e sem anomalia. O delineamento experimental adotado foi o inteiramente casualizado, sendo estabelecidos seis tratamentos com o epicarpo dos frutos maduro sem anomalia na região inferior (FMSI); frutos maduros sem injuria na região superior (FMSS); frutos verdes sem anomalia na região inferior (FVSI); frutos verdes sem anomalia na região superior (FVSS); frutos verdes com anomalia na região inferior (FVCI); frutos verdes com anomalia na região superior (FVCS). Dentre as substâncias analisadas, os carotenoides, os taninos e os fenóis totais mostram indicativos para a caracterização do anelamento. Tanto substâncias fenólicas quanto carotenoides apresentam propriedades antioxidantes e, dessa forma, poderiam estar relacionadas à defesa antioxidante causada por um fator de estresse ainda desconhecido, que promove o "anelamento" característico apresentado pelas goiabas.

Intestinal Anti-Inflammatory Activity of Baccharis dracunculifolia in the Trinitrobenzenesulphonic Acid Model of Rat Colitis

Baccharis dracunculifolia DC (Asteraceae) is a Brazilian medicinal plant popularly used for its antiulcer and anti-inflammatory properties. This plant is the main botanical source of Brazilian green propolis, a natural product incorporated into food and beverages to improve health. The present study aimed to investigate the chemical profile and intestinal anti-inflammatory activity of B. dracunculifolia extract on experimental ulcerative colitis induced by trinitrobenzenosulfonic acid (TNBS). Colonic damage was evaluated macroscopically and biochemically through its evaluation of glutathione content and its myeloperoxidase (MPO) and alkaline phosphatase activities. Additional in vitro experiments were performed in order to test the antioxidant activity by inhibition of induced lipid peroxidation in the rat brain membrane. Phytochemical analysis was performed by HPLC using authentic standards. The administration of plant extract (5 and 50 mgkg(-1)) significantly attenuated the colonic damage induced by TNBS as evidenced both macroscopically and biochemically. This beneficial effect can be associated with an improvement in the colonic oxidative status, since plant extract prevented glutathione depletion, inhibited lipid peroxidation and reduced MPO activity. Caffeic acid, p-coumaric acid, aromadendrin-4-O-methyl ether, 3-prenyl-p-coumaric acid, 3,5-diprenyl-p-coumaric acid and baccharin were detected in the plant extract.

Evaluation of protective effects of fish oil against oxidative damage in rats exposed to methylmercury

The present study evaluates a possible protective effect of fish oil against oxidative damage promoted by methylmercury (MeHg) in sub-chronically exposed rats. Reduced glutathione peroxidase and catalase enzyme activity and reduced glutathione levels were observed in MeHg-exposed animals compared to controls. Methylmercury exposure was also associated with DNA damage. Administration of fish oil to the methylmercury-exposed animals did not ameliorate enzyme activity or glutathione levels. On the other hand, a significant DNA protective effect (about 30%) was observed with fish oil treatment. There were no differences in the total mercury concentration in rat liver, kidney, heart or brain after MeHg administration with or without fish oil co-administration. Histopathological analyses showed a significant leukocyte infiltration in rat tissues after MeHg exposure, but this effect was significantly reduced after co-administration of fish oil. Taken together, our findings demonstrate oxidative damage even after low-level MeHg exposure and the protective effect of fish oil. This protection seems not to be related to antioxidant defenses or mercury re-distribution in rat tissues. It is probably due to the anti-inflammatory effects of fish oil. (C) 2010 Elsevier Inc. All rights reserved.

Homocysteine induces oxidative stress, inflammatory infiltration, fibrosis and reduces glycogen/glycoprotein content in liver of rats

Hyperhomocysteinemia has been related to various diseases, including homocystinuria, neurodegenerative and hepatic diseases. In the present study we initially investigated the effect of chronic homocysteine administration on some parameters of oxidative stress, named total radical-trapping antioxidant potential, total antioxidant reactivity, catalase activity, chemiluminescence, thiobarbituric acid-reactive substances, and total thiol content in liver of rats. We also performed histological analysis, evaluating steatosis, inflammatory infiltration, fibrosis, and glycogen/glycoprotein content in liver tissue sections from hyperhomocysteinemic rats. Finally, we evaluated the activities of aminotransferases in liver and plasma of hyperhomocysteinemic rats. Wistar rats received daily subcutaneous injection of Hcy from their 6th to their 28th day of life. Twelve hours after the last injection the rats were sacrificed, liver and plasma were collected. Hyperhomocysteinemia decreased antioxidant defenses and total thiol content, and increased lipid peroxidation in liver of rats, characterizing a reliable oxidative stress. Histological analysis indicated the presence of inflammatory infiltrate, fibrosis and reduced content of glycogen/glycoprotein in liver tissue sections from hyperhomocysteinemic rats. Aminotransferases activities were not altered by homocysteine. Our data showed a consistent profile of liver injury elicited by homocysteine, which could contribute to explain, at least in part, the mechanisms involved in human liver diseases associated to hyperhomocysteinemia. (C) 2009 ISDN. Published by Elsevier Ltd. All rights reserved.

Peripheral Oxidative Stress Biomarkers in Mild Cognitive Impairment and Alzheimer`s Disease

Oxidative stress has been associated with normal aging and Alzheimer`s disease (AD). However, little is known about oxidative stress in mild cognitive impairment (MCI) patients who present a high risk for developing AD. The aim of this study was to investigate plasma production of the lipid peroxidation marker, malonaldehyde (MDA) and to determine, in erythrocytes, the enzymatic antioxidant activity of catalase, glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST) in 33 individuals with MCI, 29 with mild probable AD and 26 healthy aged subjects. GR/GPx activity ratio was calculated to better assess antioxidant defenses. The relationship between oxidative stress and cognitive performance was also evaluated by the Mini Mental State Examination (MMSE). AD patients showed higher MDA levels than both MCI and healthy elderly subjects. MCI subjects also exhibited higher MDA levels compared to controls. Catalase and GPx activity were similar in MCI and healthy individuals but higher in AD. GR activity was lower in MCI and AD patients than in healthy aged subjects. Additionally, GR/GPx ratio was higher in healthy aged subjects, intermediate in MCI and lower in AD patients. No differences in GST activity were detected among the groups. MMSE was negatively associated with MDA levels (r = -0.31, p = 0.028) and positively correlated with GR/GPx ratio in AD patients (r = 0.68, p < 0.001). MDA levels were also negatively correlated to GR/GPx ratio (r = -0.31, p = 0.029) in the AD group. These results suggest that high lipid peroxidation and decreased antioxidant defenses may be present early in cognitive disorders.

Peroxymonocarbonate and Carbonate Radical Displace the Hydroxyl-like Oxidant in the Sod1 Peroxidase Activity under Physiological Conditions

Despite being one of the most important antioxidant defenses, Cu,Zn-superoxide dismutase (Sod1) has been frequently associated with harmful effects, including neurotoxicity. This toxicity has been attributed to immature forms of Sod1 and extraneous catalytic activities. Among these, the ability of Sod1 to function as a peroxidase may be particularly relevant because it is increased in bicarbonate buffer and produces the reactive carbonate radical. Despite many studies, how this radical forms remains unknown. To address this question, we systematically studied hSod1 peroxidase activity in the presence of nitrite, formate, and bicarbonate-carbon dioxide. Kinetic analyses of hydrogen peroxide consumption and of nitrite, formate, and bicarbonate-carbon dioxide oxidation showed that the Sod1-bound hydroxyl-like oxidant functions in the presence of nitrite and formate. In the presence of bicarbonate-carbon dioxide, this oxidant is replaced by peroxymonocarbonate, which is then reduced to the carbonate radical. Peroxymonocarbonate intermediacy was evidenced by (13)C NMR experiments showing line broadening of its peak in the presence of Zn,ZnSod1. In agreement, peroxymonocarbonate was docked into the hSod1 active site, where it interacted with the conserved Arg(143). Also, a reaction between peroxymonocarbonate and Cu(I)Sod1 was demonstrated by stopped-flow experiments. Kinetic simulations indicated that peroxymonocarbonate is produced during Sod1 turnover and not in bulk solution. In the presence of bicarbonate-carbon dioxide, sustained hSod1-mediated oxidations occurred with low steady-state concentrations of hydrogen peroxide (4-10 mu M). Thus, carbonate radical formation through peroxymonocarbonate may be a key event in Sod1-induced toxicity.

Nicorandil protects cardiac mitochondria against permeability transition induced by ischemia-reperfusion

Ischemia followed by reperfusion is known to negatively affect mitochondrial function by inducing a deleterious condition termed mitochondrial permeability transition. Mitochondrial permeability transition is triggered by oxidative stress, which occurs in mitochondria during ischemia-reperfusion as a result of lower antioxidant defenses and increased oxidant production. Permeability transition causes mitochondrial dysfunction and can ultimately lead to cell death. A drug able to minimize mitochondrial damage induced by ischemia-reperfusion may prove to be clinically effective. We aimed to analyze the effects of nicorandil, an ATP-sensitive potassium channel agonist and vasodilator, on mitochondrial function of rat hearts and cardiac HL-1 cells submitted to ischemia-reperfusion. Nicorandil decreased mitochondrial swelling and calcium uptake. It also decreased reactive oxygen species formation and thiobarbituric acid reactive substances levels, a lipid peroxidation biomarker. We thus confirm previous reports that nicorandil inhibits mitochondrial permeability transition and demonstrate that nicorandil inhibits this process by preventing oxidative damage and mitochondrial calcium overload induced by ischemia-reperfusion, resulting in improved cardiomyocyte viability. These results may explain the good clinical results obtained when using nicorandil in the treatment of ischemic heart disease.

HPLC microfractionation of flavones and antioxidant (radical scavenging) activity of Saccharum officinarum L.

The antioxidant activity of sugarcane (Saccharum officinarum L.) juice towards DPPH reagent was determined (EC50) and the main compounds with radical scavenging activity in juice and leaves extracts were identified by HPLC-UV/PAD analysis combined with HPLC microfractionation monitored by TLC using β-carotene and DPPH as the detection reagents. In sugarcane leaves, luteolin-8-C-(rhamnosylglucoside) (1) was the most important compound with radical scavenging activity; in sugarcane juice, the flavones diosmetin-8-C-glucoside (2), vitexin (3) schaftoside (9), isoschaftoside (10) and 4',5'-dimethyl-luteolin-8-C-glucoside (11) were the most relevant compounds. The content of juice flavonoids (0.241 ± 0.001 mg total flavonoids/mL juice), comparable to other food sources of flavonoids, suggest the potential of sugarcane as a dietary source of natural antioxidants. However, the low antioxidant ability of sugarcane juice (EC50 = 100.2 ± 2.6 g L-1) also points to the need for further studies about the dietary intake of sugarcane flavonoids and its effects on human health.

Antioxidant and antimicrobial properties of 2-(4,5-dihydro-1H-pyrazol-1-yl)-pyrimidine and 1-carboxamidino-1H-pyrazole derivatives

Five previously synthesized 4-trifluoromethyl-2-(5-aryl-3-styryl-1H-pyrazol-1yl)-pyrimidines and six 5-aryl-3-styryl-1-carboxamidino-1H-pyrazole derivatives were screened for their antioxidant proprieties. The antioxidant activities were evaluated by using the DPPH and the HRP/luminol/H2O2 chemiluminescence assay systems and for their antimicrobial activity (MIC). The results were good for those series in some concentration in comparison with the standards.

Natural antioxidant from yerba maté (Ilex paraguariensis St. Hil.) prevents hamburger peroxidation

The aim of this study was to evaluate whether yerba maté alcoholic extracts at very low concentrations (0.01 and 0.1%), prevent/retard lipid peroxidation in beef hamburgers without impairing sensory acceptability. For this TBARs and hexanal levels, fatty acid profile and cholesterol oxides were evaluated as oxidation parameters in beef hamburgers during 90 days' storage. The addition of 0.01% yerba maté ethanolic extracts proved inefficient in restraining the lipid peroxidation while the addition of 0.1% resulted in efficient antioxidant activity. Sensory evaluation of hamburger containing 0.1% yerba maté ethanolic extracts showed good acceptability. Yerba maté ethanolic extracts could entirely or partially replace the phenolic synthetic antioxidants in beef hamburgers only when used at above legally allowed concentrations for antioxidant additives (0.01%).

Garlic (Allium sativum L.) and ready-to-eat garlic products: in vitro antioxidant activity

Garlic contains polyphenol and sulphur compounds, which are responsible for its antioxidant activity (AA). This study aimed at evaluating the AA of fresh garlic and its commercialised products and their shelf life. Fresh garlic (FG) and its products, i.e. chopped with salt (CGS), chopped without salt (CG), fried (FRG) and mixed garlic (FG with dehydrated garlic; MG) antioxidant activity was evaluated by three different methods: DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, ß-carotene/linoleic acid assay and Rancimat® method. Amongst all the analysed products, fried garlic presented the highest antioxidant activity. The free radical-scavenging activity decreased during the shelf life of all analysed products that correlated with the decrease in the total polyphenol content. Our findings suggest that some compounds other than phenol may have contributed towards this outcome

Antioxidant activity and phenolic composition of herbal infusions consumed in Brazil

Processed tea and herbal infusions were Studied for their phenol content, antioxidant activity and main flavonoids. Total phenolics were determined by Folin-Ciocalteu method and ranged from N.D. to 46.46 +/- 0.44 mg/g GAE. Flavonoids were investigated by HPLC, and myricetin, quercetin, kaempferol were identified in black, green, and chamomile tea. Antioxidant activity was evaluated using two methods: DPPH and beta-carotene bleaching test (BCB). Using the BCB, the highest activities were found for infusions of black tea, mate, lemongrass, chamomile, and fennel; whereas fresh herbal infusions presented the lowest activities. Using the DPPH method, fresh herbal infusions presented the highest activities. Processed leaves with the lowest IC50 values were green and black tea (147.63 and 288.60 mu g/mL, respectively). The results of this research show that the infusions studied are good Source of compounds presenting antioxidant activity in vitro.

Harmine and imipramine promote antioxidant activities in prefrontal cortex and hippocampus

A growing body of evidence has suggested that reactive oxygen species (ROS) may play an important role in the physiopathology of depression. Evidence has pointed to the beta-carboline harmine as a potential therapeutic target for the treatment of depression. The present study we evaluated the effects of acute and chronic administration of harmine (5, 10 and 15 mg/kg) and imipramine (10, 20 and 30 mg/kg) or saline in lipid and protein oxidation levels and superoxide dismutase (SOD) and catalase (CAT) activities in rat prefrontal cortex and hippocampus. Acute and chronic treatments with imipramine and harmine reduced lipid and protein oxidation, compared to control group in prefrontal cortex and hippocampus. The SOD and CAT activities increased with acute and chronic treatments with imipramine and harmine, compared to control group in prefrontal cortex and hippocampus. In conclusion, our results indicate positive effects of imipramine antidepressant and beta-carboline harmine of oxidative stress parameters, increasing SOD and CAT activities and decreasing lipid and protein oxidation.