Quercetin ameliorates glucose and lipid metabolism and improves antioxidant status in postnatally monosodium glutamate-induced metabolic alterations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Decreased Total Antioxidant Capacity in Plasma, but Not Tissue, in Experimental Colitis

The aim of the present work was to compare colonic mucosa and plasmatic oxidative stress measured concomitantly and with different degrees of injury in rats with colitis induced by trinitrobenzene sulfonic acid. Three groups were studied: control group, colitis group, and colitis exacerbated by diclofenac. Enzymatic markers of colon injury showed enhanced activity in both groups with colitis. The colitis group treated with diclofenac presented higher colonic damage score than the other groups. In both groups with colitis, higher values of tert butyl hydroperoxide-initiated-chemiluminescence and thiobarbituric acid-reactive substances in tissue and decreased total radical-trapping antioxidant potential (TRAP) levels in plasma were found. In conclusion, independently of the degree of colonic mucosa injury and inflammation, oxidative stress in tissue occurs as a consequence of pro-oxidants increase, and is not explained by a reduction of antioxidant defenses. In both conditions, TRAP determination decreases in plasma, but not in tissue.

Intestinal intraluminal injection of glutamine increases trolox total equivalent antioxidant capacity (TEAC) in hepatic ischemia-reperfusion

OBJETIVO: Avaliar em um modelo experimental de isquemia-reperfusão hepática os efeitos da injeção intraluminal de glutamina na capacidade anti-oxidante total em equivalência ao trolox (TEAC) do plasma, verificando a aplicabilidade de modificações ao método original de dosagem. MÉTODOS: Trinta ratos Wistar foram submetidos a laparotomia e confecção de uma alça fechada de 20 cm de comprimento envolvendo o intestinal delgado distal seguido do clampeamento do hilo hepático por 30 minutos e reperfusão por 5 minutos. Na alça fechada foi injetada glutamina (grupo glutamina; n=10) ou água destilada (grupo controle; n=10). Em dez animais (grupo sham) não foi realizado clampeamento hilar. Coletou-se sangue para dosagem da capacidade antioxidante total em equivalência ao trolox em condições modificadas de temperatura, proporções relativas dos reagentes e tempo de leitura sob espectrofotometria. RESULTADOS: A capacidade antioxidante total foi significantemente maior (p<0.05) no grupo glutamina que no grupo controle (1,60[1,55-1,77] vs 1,44[1,27-1,53]) e grupo sham (1,60[1,55-1,77] vs 1,48[1,45-1,59]). Não houve diferenças estatísticas entre o grupo controle e o grupo sham. CONCLUSÃO: A glutamina melhorou a capacidade anti-oxidante total plasmática. O método de dosagem refletiu consistentemente alterações na defesa anti-oxidante nesse modelo experimental.

Effects of the acute exposition to glyphosate-based herbicide on oxidative stress parameters and antioxidant responses in a hybrid Amazon fish surubim (Pseudoplatystoma sp)

The aim of this study was to investigate the effects of acute glyphosate (active ingredient) exposure on the oxidative stress biomarkers and antioxidant defenses of a hybrid surubim (Pseudoplatystoma sp). The fish were exposed to different herbicide concentrations for 96 h. The thiobarbituric acid-reactive substances (TBARS), protein carbonyls and antioxidant responses were verified. The 15 mg a.p L-1 of herbicide resulted in the death of 50% of the fish after 96 h. An increase in liver and muscle TBARS levels was observed when fish were exposed to the herbicide. The protein carbonyl content was also increased in the liver (4.5 mg a.p L-1 concentration) and brain (2.25 mg a.p L-1 concentration). The antioxidant activities decreased in the liver and brain after exposure to herbicide. Levels of ascorbic acid in the liver (2.25 mg a.p L-1 and 4.5 mg a.p L-1 concentrations) and brain (2.25 mg a.p L-1 concentration) were increased post-treatment. Levels of total thiols were increased in the liver and brain (2.25 mg L-1 and 7.5 mg a.p L-1, respectively). Glyphosate exposure, at the tested concentrations affects surubim health by promoting changes that can affect their survival in natural environment. Some parameters as TBARS and protein carbonyl could be early biomarkers for Roundup exposure in this fish species. (C) 2014 Elsevier Inc. All rights reserved.

Enteral nutrition feeding alters antioxidant activity in unstimulated whole saliva composition of patients with neurological disorders

Patients with neurological disorders have an increased risk of oral and systemic diseases due to compromised oral hygiene. If patients lose the ability to swallow and chew food as a result of their disorder, enteral nutrition is often utilized. However, this type of feeding may modify salivary antioxidant defenses, resulting in increased oxidative damage and the emergence of various diseases. The aim of this study was to evaluate the effects of enteral nutrition on biochemical parameters in the unstimulated whole saliva composition of patients with neurological disorders. For this, enzymatic (superoxide dismutase - SOD; glutathione peroxidase - GPx) and non-enzymatic (uric acid; ferric ion reducing antioxidant power - FRAP) antioxidant activity, as well as a marker for oxidative damage (thiobarbituric acid reactive substances - TBARS) were analyzed. Unstimulated whole saliva was collected from 12 patients with neurological disorders and tube-feeding (tube-fed group - TFG), 15 patients with neurological disorders and normal feeding via the mouth (non-tube-fed group - NTFG), and 12 volunteers without neurological disorders (control group - CG). The daily oral hygiene procedures of TFG and NTFG patients were similar and dental care was provided monthly by the same institution's dentist. All patients exhibited adequate oral health conditions. The salivary levels of FRAP, uric acid, SOD, GPx, TBARS, and total protein were compared between studied groups. FRAP was increased (p < 0.05) in the NTFG (4651 +/- 192.5 mmol/mL) and the TFG (4743 +/- 116.7 mmol/mL) when compared with the CG (1844 +/- 343.8 mmol/mL). GPx values were lower (p < 0.05) in the NTGF (8.24 +/- 1.09 mmol/min/mg) and the TFG (8.37 +/- 1.60 mmol/min/mg) than in the CG (15.30 +/- 2.61 mmol/min/mg). Uric acid in the TFG (1.57 +/- 0.23 mg/dL) was significantly lower than in the NTFG (2.34 +/- 0.20 mg/dL) and the CG (3.49 +/- 0.21 mg/dL). Protein was significantly lower in the TFG (5.35 +/- 0.27 g/dL) than in the NTFG (7.22 +/- 0.57 g/dL) and the CG (7.86 +/- 0.54 g/dL). There was no difference in the salivary flow rate and SOD between groups. Enteral nutrition in patients with neurological disorders was associated with lower oxidative damage, resulting in increased salivary. antioxidant capacity. These results emphasize the importance of oral care for this population to prevent oral and systemic diseases. (C) 2014 Elsevier Ltd. All rights reserved.

Exercise and oxidative stress: p,otential effects of antioxidant dietary strategies in sports

Free radicals are produced during aerobic cellular metabolism and have key roles as regulatory mediators in signaling processes. Oxidative stress reflects an imbalance between production of reactive oxygen species and an adequate antioxidant defense. This adverse condition may lead to cellular and tissue damage of components, and is involved in different physiopathological states, including aging, exercise, inflammatory, cardiovascular and neurodegenerative diseases, and cancer. In particular, the relationship between exercise and oxidative stress is extremely complex, depending on the mode, intensity, and duration of exercise. Regular moderate training appears beneficial for oxidative stress and health. Conversely, acute exercise leads to increased oxidative stress, although this same stimulus is necessary to allow an up-regulation in endogenous antioxidant defenses (hormesis). Supporting endogenous defenses with additional oral antioxidant supplementation may represent a suitable noninvasive tool for preventing or reducing oxidative stress during training. However, excess of exogenous antioxidants may have detrimental effects on health and performance. Whole foods, rather than capsules, contain antioxidants in natural ratios and proportions, which may act in synergy to optimize the antioxidant effect. Thus, an adequate intake of vitamins and minerals through a varied and balanced diet remains the best approach to maintain an optimal antioxidant status. Antioxidant supplementation may be warranted in particular conditions, when athletes are exposed to high oxidative stress or fail to meet dietary antioxidant requirements. Aim of this review is to discuss the evidence on the relationship between exercise and oxidative stress, and the potential effects of dietary strategies in athletes. The differences between diet and exogenous supplementation as well as available tools to estimate effectiveness of antioxidant intake are also reported. Finally, we advocate the need to adopt an individualized diet for each athlete performing a specific sport or in a specific period of training, clinically supervised with inclusion of blood analysis and physiological tests, in a comprehensive nutritional assessment. (C) 2015 Elsevier Inc. All rights reserved.

(Table 1) Antioxidant concentrations in liver of wild sea bird chicks from the Norwegian arctic region

The efficiency of antioxidant defenses and relationship with body burden of metal and organic contaminants has not been previously investigated in arctic seabirds, neither in chicks nor in adults. The objective of this study was to compare such defenses in chicks from three species, Black-legged kittiwake (Rissa tridactyla), Northern fulmar (Fulmarus glacialis), and Herring gull (Larus argentatus), and the relationship with tissue concentrations of essential metals such as selenium and iron and halogenated organic compounds, represented by polychlorinated biphenyl (PCB). The results showed significant species-specific differences in the antioxidant responses which also corresponded with metal and PCB levels in different ways. The capability to neutralize hydroxyl radicals (TOSC-HO°) and the activities of catalase and Se-dependent glutathione peroxidases (GPX) clearly increased in species with the higher levels of metals and PCBs, while the opposite trend was observed for Se-independent GPX, TOSC against peroxyl radicals (ROO°) and peroxynitrite (ONOOH). Less clear relationships were obtained for glutathione levels, GSH/GSSG ratio, glutathione reductase and superoxide dismutase. The results showed differences in antioxidant efficiency between the species, and some of these defenses exhibited dose-response-like relationships with measured levels of selenium, iron and XPCBs. PCBs, selenium and iron levels were positively related to the responses of antioxidants with potential to reduce HO°/H2O2 (Se-dependent GPX, CAT and TOSC against HO°). However, direct causal relationships between antioxidant responses and contaminant concentrations could not be shown on individual level. Varying levels of metals and contaminants due to different diet and age were probably the main explanations for the species differences in antioxidant defense.

Antioxidant Properties of Bee Products of Plant- Origin Part 2. Propolis and Pollen

Over the last years, the hive products such as propolis and pollen have been highlighted due to their potential health benefits, including antioxidant abilities that have been correlated with their content in phenolic compounds. Regardless of the several factors that may affect propolis and pollen antioxidant activity, these products have been shown to possess, either through the use of in vitro or in vivo models, important features concerning the modulation of cellular oxidative stress caused by environmental factors (e.g. UV-light), metals, pesticides and other xenobiotics. This modulatory effect focus not only on the capture of radicals that these elements might eventually generate, but also by the activation of cellular antioxidant mechanisms such as enzymatic antioxidants or by modifying gene expression patterns. Although the mechanisms behind these responses are not fully known, it has been showed that caffeic acid phenethyl ester, pinocembrin and chrisin are some of the compounds responsible for some of these responses. Taking into account the gathered results, propolis and pollen can be viewed as potential agents in the re-stabilization of cellular oxidative imbalance and in the prevention of oxidative stress related diseases.

Effects of anitoxidant supplementation and exercise training on erythrocyte antioxidant enzymes

Erythrocytes transport oxygen to tissues and exercise-induced oxidative stress increases erythrocyte damage and turnover. Increased use of antioxidant supplements may alter protective erythrocyte antioxidant mechanisms during training. Aim of study: To examine the effects of antioxidant supplementation, (alpha-lipoic acid and a-tocopherol) and/or endurance training on the antioxidant defenses of erythrocytes. Methods: Young male Wistar rats were. assigned to (1) sedentary; (2) sedentary and antioxidant-supplemented; (3) endurance-trained; or (4) endurance-trained and antioxidant-supplemented groups for 14 weeks. Erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities, and plasma malondialdehyde (MDA) were then measured. Results: Antioxidant supplementation had no significant effect (p > 0.05) on activities of antioxidant enzymes in sedentary animals. Similarly, endurance training alone also bad no effect (p > 0.05). GPX (125.9 2.8 vs. 121.5 3.0 U.gHb(-1), p < 0.05) and CAT (6.1 0.2 vs. 5.6 0.2 U.mgHb-1, p < 0.05) activities were increased in supplemented trained animals compared to non-supplemented sedentary animals whereas SOD (61.8 4.3 vs. 52.0 5.2 U.mgHb(-1), p < 0.05) activity was decreased. Plasma MDA was not different among groups (p > 0.05). Conclusions: In a rat model, the combination of exercise training and antioxidant supplementation increased antioxidant enzyme activities (GPX, CAT) compared with each individual intervention.

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.

Efectos de la suplementación con glutamina sobre el sistema antioxidante y la peroxidación lipídica en pacientes críticos con nutrición parenteral

INTRODUCTION In the critically ill patient, there is a continuous production of reactive oxygen species (ROS) that need to be neutralized to prevent oxidative stress (OS). Quantitatively speaking, the glutathione system (GSH) is the most important anti-oxidant endogenous defense. To increase it, glutamine supplementation has been shown to be effective by protecting against the oxidative damage and reducing the morbimortality. OBJECTIVE To assess the effect of adding an alanylglutamine dipeptide to PN on lipid peroxidation lipidica and glutathione metabolism, as well as its relationship with morbidity in critically ill patients. METHODS Determination through spectrophotometry techniques of glutathione peroxidase, glutathione reductase, total glutathione, and maloniladdehyde at admission adn after seven days of hospitalization at the Intensive Care Unit (ICU) in 20 patients older than 18 years on parenteral nutrition therapy. RESULTS The group of patients receiving parenteral nutrition with glutamine supplementation had significant increases in total glutathione (42.35+/-13 vs 55.29+/-12 micromol/l; p<0.05) and the enzymatic activity of glutathione peroxidasa (470+/-195 vs 705+/-214 micromol/l; p<0.05) within one week of nutritional therapy, whereas the group on conventional parenteral nutrition did not show significant changes of any of the parameters studied (p>0.05). However, both mortality and ICU stay were not different between the study group, whereas the severity (assessed by the SOFA score) was lower in the group of patients receiving glutamine (SOFA 5+/-2 vs 8+/-1.8; p<0.05). CONCLUSIONS Glutamine intake in critically ill patients improves the antioxidant defenses, which leads to lower lipid peroxidation and lower morbidity during admission at the ICU.

Fecundity and survival in relation to resistance to oxidative stress in a free-living bird.

Major life history traits, such as fecundity and survival, have been consistently demonstrated to covary positively in nature, some individuals having more resources than others to allocate to all aspects of their life history. Yet, little is known about which resources (or state variables) may account for such covariation. Reactive oxygen species (ROS) are natural by-products of metabolism and, when ROS production exceeds antioxidant defenses, organisms are exposed to oxidative stress that can have deleterious effects on their fecundity and survival. Using a wild, long-lived bird, the Alpine Swift (Apus melba), we examined whether individual red cell resistance to oxidative stress covaried with fecundity and survival. We found that males that survived to the next breeding season tended to be more resistant to oxidative stress, and females with higher resistance to oxidative stress laid larger clutches. Furthermore, the eggs of females with low resistance to oxidative stress were less likely to hatch than those of females with high resistance to oxidative stress. By swapping entire clutches at clutch completion, we then demonstrated that hatching failure was related to the production of low-quality eggs by females with low resistance to oxidative stress, rather than to inadequate parental care during incubation. Although male and female resistance to oxidative stress covaried with age, the relationships among oxidative stress, survival, and fecundity occurred independently of chronological age. Overall, our study suggests that oxidative stress may play a significant role in shaping fecundity and survival in the wild. It further suggests that the nature of the covariation between resistance to oxidative stress and life history traits is sex specific, high resistance to oxidative stress covarying primarily with fecundity in females and with survival in males.

Myocardial tolerance to ischemia-reperfusion injury, training intensity and cessation.

Training has been shown to induce cardioprotection. The mechanisms involved remain still poorly understood. Aims of the study were to examine the relevance of training intensity on myocardial protection against ischemia/reperfusion (I/R) injury, and to which extent the beneficial effects persist after training cessation in rats. Sprague-Dawley rats trained at either low (60% [Formula: see text]) or high (80% [Formula: see text]) intensity for 10 weeks. An additional group of highly trained rats was detrained for 4 weeks. Untrained rats served as controls. At the end of treatment, rats of all groups were split into two subgroups. In the former, rats underwent left anterior descending artery (LAD) ligature for 30 min, followed by 90-min reperfusion, with subsequent measurement of the infarct size. In the latter, biopsies were taken to measure heat-shock proteins (HSP) 70/72, vascular endothelial growth factor (VEGF) protein levels, and superoxide dismutase (SOD) activity. Training reduced infarct size proportionally to training intensity. With detraining, infarct size increased compared to highly trained rats, maintaining some cardioprotection with respect to controls. Cardioprotection was proportional to training intensity and related to HSP70/72 upregulation and Mn-SOD activity. The relationship with Mn-SOD was lost with detraining. VEGF protein expression was not affected by either training or detraining. Stress proteins and antioxidant defenses might be involved in the beneficial effects of long-term training as a function of training intensity, while HSP70 may be one of the factors accounting for the partial persistence of myocardial protection against I/R injury in detrained rats.