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RESUMO Considerado um poluente prioritário de reconhecida toxicidade e recalcitrância, o 2,4-dinitrofenol (2,4-DNF) presente em águas residuárias dificulta tratamentos convencionais, especialmente os de princípio biológico, como lagoas aeradas e sistema de lodos ativados. Em função de sua potencialidade de transformar a estrutura de poluentes em elementos de capacidade poluidora reduzida, os processos oxidativos avançados (POAs) representam atualmente uma alternativa para o tratamento de efluentes contaminados com compostos dessa natureza. A presente pesquisa teve como objetivo realizar estudos de degradação de 2,4-DNF em solução aquosa por meio de processos de oxidação avançada do tipo Fenton utilizando uma fonte não convencional de ferro na forma de um resíduo siderúrgico (carepa de aço). A condução de um delineamento experimental fundamentado em planejamento fatorial de experimentos revelou que as variáveis quantidade de peróxido de hidrogênio e de carepa influenciaram significativamente a degradação de 2,4-DNF, proporcionando, em condições otimizadas (20 g de carepa, 0,5 mL de H2O2 em pH 3), elevada eficiência na degradação tanto do composto modelo quanto de seus intermediários reacionais, tendo reduzido também a toxicidade aguda medida na forma de inibição de crescimento de E. coli. Ensaios adicionais sugeriram que os mecanismos reacionais pelos quais ocorre a degradação do 2,4-DNF são mediados tanto pela superfície das partículas de carepa quanto pelo ferro lixiviado, caracterizando o processo como uma combinação de oxidação homogênea e heterogênea. Finalmente, ensaios de reusabilidade e operação em reator de fluxo contínuo sugeriram significativa potencialidade do sistema carepa/H2O2.
ABSTRACT Considered a priority pollutant of recognized toxicity and recalcitrance, 2.4-dinitrophenol (2.4-DNP) present in wastewater hinders conventional treatments such as filtration, chemical coagulation, activated sludge system and activated carbon adsorption. Due to the potential of advanced oxidation processes (AOP) to transform the structure of pollutants into elements of reduced pollutant capacity, they presently represent an alternative for the treatment of effluents contaminated with these compounds. The present research aimed to study the degradation of 2.4-DNP in aqueous solution through advanced Fenton-type oxidation processes, using an unconventional source of iron in the form of a steel residue (steel waste). The conduction of an experimental design based on the factorial planning of experiments revealed that the variables hydrogen peroxide quantity and scale significantly influenced 2.4-DNF degradation, providing, under optimized conditions (20 g of steel waste, 0.5 mL of H2O2 at pH 3) high degradation efficiency of both the model compound and its reaction intermediates, as well as reducing acute toxicity, measured as E. coli growth inhibition. Further trials have suggested that the reaction mechanisms by which 2.4-DNF degradation occurs are mediated by both the surface of steel waste particles and the leached iron, characterizing the process as a combination of homogeneous and heterogeneous oxidation. Finally, reusability and continuous flow reactor operation tests suggested the significant potential of the steel waste/ H2O2 system.
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Free radicals are generated by both enzymatic and non-enzymatic reactions. The main source of free radicals in enzymatic reactions include those involved in phagocytosis, respiratory chain, in prostaglandin synthesis, and in cytochrome p450 system. Current investigation was to examine invitro antioxidant potential of Cassia absus (Linn). MethodsThe aerial parts of Cassia absus (Linn) were powdered and the dry powder was subjected to extraction with various solvents (PE, EA and methanol) through Soxhlet extractor. The aerial parts of different concentrates (pet. ether, ethyl acetate and methanol) of Cassia absus was evaluated for its in-vitro antioxidant potential by hydroxyl radical, FRAP activity taking ascorbate used as standard for the both methods and total flavonoids content was estimated as equivalent to rutin. ResultsThe methanolic concentrates of Cassia absus & standard exhibited antioxidant potential possessing IC50 196 µg/mL & 65 µg/mL (hydroxyl radical) 216 µg/mL & 50 µg/mL (FRAP activity) respectively. Methanolic concentrates of Cassia absus were more efficient in hydroxyl radical, FRAP activity compared EA & PE concentrates. The methanolic and EA concentrates of Cassia absus showed the total flavonoids content (10.22 ± 0.40, 4.03 ± 0.47 respectively). The difference in scavenging potential of the extracts can be due to variation in the percentage of bioactive compound flavonoids present in methanolic extracts. Invitro antioxidant studies show that methanolic concentrates of Cassia absus have better antioxidant activity due to the presence of total flavonoids content. ConclusionsThis result indicates that methanolic concentrates of aerial parts of Cassia absus could serve as natural antioxidant, which may be useful in preventing free radical induced diseases.
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Background: Burdock (Arctium lappa L.) is a fructan-rich plant with prebiotic potential. The aim of this study was to develop an efficient enzymatic route to prepare fructooligosaccharides (FOS)-rich and highly antioxidative syrup using burdock root as a raw material. Results: Endo-inulinase significantly improved the yield of FOS 2.4-fold while tannase pretreatment further increased the yield of FOS 2.8-fold. Other enzymes, including endo-polygalacturonase, endo-glucanase and endo-xylanase, were able to increase the yield of total soluble sugar by 11.1% (w/w). By this process, a new enzymatic process for burdock syrup was developed and the yield of burdock syrup increased by 25% (w/w), whereas with FOS, total soluble sugars, total soluble protein and total soluble polyphenols were enhanced to 28.8%, 53.3%, 8.9% and 3.3% (w/w), respectively. Additionally, the scavenging abilities of DPPH and hydroxyl radicals, and total antioxidant capacity of the syrup were increased by 23.7%, 51.8% and 35.4%, respectively. Conclusions: Our results could be applied to the development of efficient extraction of valuable products from agricultural materials using enzyme-mediated methods.
Subject(s)
Oligosaccharides/chemistry , Plant Roots/chemistry , Fructose/chemistry , Glycoside Hydrolases/metabolism , Antioxidants/chemistry , Oligosaccharides/metabolism , Polygalacturonase/metabolism , Carboxylic Ester Hydrolases/metabolism , Chromatography, High Pressure Liquid , Hydroxyl Radical , Arctium , Functional Food , Polyphenols , Fructose/metabolism , Antioxidants/metabolismABSTRACT
Objective: This study investigated the in vitro antioxidant and free radical potentials of methanol extracts of Uvaria chamae leaves and roots. Methods: Fresh Uvaria chamae leaves and roots were air dried, pulverized and extracted using methanol. Phytochemical, total phenolic, flavonoids, antioxidant and tannin contents, DPPH, hydroxyl, and superoxide radical scavenging properties of the extracts were determined using standard methods. Results: In vitro antioxidant potentials revealed that methanol extract of Uvaria chamae leaves contains vitamin A (4871±79.21 I. U) and vitamin C (1.72±0.02%) while the root extract contains vitamin A (673.28±0.00I. U) and vitamin C (1.66±0.01%). Both extracts had equal contents of vitamin E (8.83±0.04 mg/100g). The leaf extract scavenged 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) in a concentration dependent manner with the correlation coefficient (R2) of 0.839 and effective concentration (EC50) of 31.19 µg/ml, while the root extract scavenged DPPH with R2 of0.778 and EC50 of 14.00 µg/ml. The leaf and root extracts scavenged superoxide radical and hydroxyl radical with EC50 of 5.93 µg/ml and 719.45 µg/ml; 107.89 µg/ml and 912.01 µg/ml respectively compared to the EC50 of ascorbic standard (30.27 µg/ml) and EC50 of vitamin E standard (106.66µg/ml) respectively. The leaf extract showed significantly higher (p<0.05) anti radical power (ARP) of superoxide (0.17) compared to the root extract (0.0014) and the root extract showed significantly higher (p<0.05) ARP of DPPH (0.071) compared to the leaf extract (0.032). Conclusion: The leaves and roots of Uvaria chamae are rich in natural antioxidants that can be exploited in the treatment of diseases related to oxidative stress.
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p-Hydroxybenzoic acid can be oxidized by hydroxyl radicals ( · OH) to produce electroactive 3,4-dihydroxybenzoic acid (3,4-DHBA). Therefore, it can be used as a probe to detect ·OH. In this work, 3,4-DHBA/ PPy / TiO2 molecularly imprinted polymer film was prepared for indirect determination of ·OH based on its recognition ability for 3,4-DHBA. The sensor was constructed by using pyrrole as the functional monomer and 3, 4-DHBA as the template molecule. The sensor was characterized by scanning electron microscope and different electrochemical methods. The preparation and determination conditions, such as the electropolymerization cycle number, pH value in the electropolymerization process, and elution time, were optimized. Under the optimal conditions, a linear range of 1. 0×10-8-1. 0×10-6 mol/ L was obtained for 3,4-DHBA and the detection limit was down to 4. 2×10-9 mol/ L (S / N = 3). This new approach was of low cost and convenience, and was successfully applied to measure the concentration of ·OH in the atmosphere.
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Objective@#To investigate the influence of sodium nitrite exposure on sulfhemoglobin and hydroxyl radicals in mice.@*Methods@#A total of 60 mice were randomly divided into low-, middle-, and high-dose groups (the concentrations of sodium nitrite were 0.055 mg/ml, 0.110 mg/ml, and 0.220 mg/ml, respectively) and control group (treated with distilled water) , with 15 mice in each group (male/female ratio=1: 1) . A free-drink model was applied and the duration of exposure was 2 weeks. The body weight of all mice was recorded before exposure and at weeks 1 and 2 of exposure. At the end of exposure, the mice were treated with intraperitoneally injected sodium salicylate to capture the hydroxyl radicals and produce 2, 5-dihydroxybenzoic acid and 2, 3-dihydroxybenzoic acid, and high-performance liquid chromatography was used to measure their content. Spectrophotometry was used to measure the relative content of sulfhemoglobin.@*Results@#At week 2 of exposure, the low-, middle-, and high-dose groups had significantly lower body weight than the control group (22.8±2.8 g/21.6±2.8 g/21.2±3.0 g vs 25.6±2.2 g, P<0.05) . The low-, middle-, and high-dose groups had a significantly higher total content of hydroxyl radicals than the control group[ (0.015 3±0.006 5) μg/ml, (0.016 4±0.017 2) μg/ml, and (0.062 7±0.091 0) μg/ml vs (0.009 ±0.007 3) μg/ml, P<0.05]. The relative content of sulfhemoglobin was 1.54%±0.73%, 2.22%±0.44%, and 2.80%±0.69%, respectively, in the low-, middle-, and high-dose groups, and the middle- and high-dose groups had a significant increase in the relative content of sulfhemoglobin compared with the control group (2.22%±0.44%/2.80%±0.69% vs 1.76%±0.60%, P<0.05) . The content of hydroxyl radicals was positively correlated with the relative content of sulfhemoglobin (r=0.837, P<0.05) .@*Conclusion@#Sodium nitrite exposure can increase the content of sulfhemoglobin and hydroxyl radicals in blood, and there is a positive correlation between them.
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Objective To compare the strength of oxidative stress from different concentrations of oxygen administered by the accumulation of hydroxyl radicals during early reperfusion after global brain ischemia.Methods Sixteen adult male Mongolian gerbils with microdialysis probes implanted in the hippocampal CA1 were divided randomly (random number)into two groups (n =8 in each).All gerbils of both groups were subjected to 10 min bilateral carotid artery occlusion (BCAO).Then the following intervention:(a) immediate 30% O2 (near normoxia,NO group ) and (b ) immediate 100% O2 (hyperoxia,HO group).The accumulation of hydroxyl radicals (·OH)in hippocampus during reperfusion was estimated by measuring 2,3-dihydroxybenzoic acid (DHBA ) and 2,5-DHBA in microdialysis perfusate.Results Immediately after the onset of reperfusion,two groups showed markedly elevated DHBA,which returned to baseline gradually.Compared with the NO group,the HO group showed significantly higher peak DHBA and slower recovery.Conclusions Hydroxyl radical accumulation was more sensitive to inhalation of high concentration O2 during early reperfusion of global cerebral ischemia.
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Objective To explore the effects of lead acetate on free radicals and lipid peroxidation in the cerebral cor?tex, cerebellum, and hippocampus in rat brains. Methods SD rats (n=48), who were just weaned, were randomly divided in?to 4 groups base on their weight. Then the rats were fed with lead acetate in drinking water at the final concentrations of 0 mg/L (deionized water), 200 mg/L, 400 mg/L, 800 mg/L respectively. Blood lead level as well as the hydroxyl free radical inhibiting activity, the levels of hydrogen peroxide (H2O2) and malondialdehyde (MDA) in cerebral cortex, cerebellum, and hippocam?pus were measured 60 days after lead contamination in water. Results Upon lead exposure, blood lead levels increased sig?nificantly as compared with the control. The hydroxyl free radical inhibiting activity in cerebral cortex, cerebellum, and hip?pocampus decreased significantly in a dose dependent manner of lead(P < 0.05). And they all correlated negatively with blood lead level (r=-0.505,-0.414,-0.448, P<0.05). By contrast, blood lead level was positively correlated with H2O2 and MDA in these brain tissues (r=0.301, 0.411, 0.378, and 0.404, 0.324, 0.510,P < 0.05). Conclusion Lead exposure can lead to lipid peroxidation of rat brain tissues through inducing free radicals.
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ObjectiveTo investigate the protective effects of 5-hydroxy-1-methylhyantoin (HMH) on paraquat (PQ)-induced nephrotoxicity in rat and its possible mechanism.Methods Twenty-four male Sprague-Dawley (SD) rats were randomly divided into four groups: namely control, PQ, vitamin C and HMH groups, with 6 rats in each group. The rats in control group were given an injection of 2 mg/kg of normal saline intraperitoneally. The rats in PQ group were given an injection of 50 mg/kg of PQ intraperitoneally. The rats in vitamin C and HMH groups were given 1 mmol/kg of vitamin C or HMH through gastric tube right after PQ injection. The hydroxyl free radical scavenging ability of HMH and vitamin C was determined by Fenton method. Blood sample was collected after 24 hours of PQ treatment, then the animals were sacrificed and renal tissues were harvested. Blood urea nitrogen (BUN), serum creatinine (SCr), protein content of renal cortex, blood malondialdehyde (MDA), reduced glutathione (GSH) and superoxide dismutase (SOD) activity were determined.Results Both vitamin C and HMH showed a very good ability to scavenge hydroxyl radicals, and the 50% inhibiting concentration (IC50) was both 4.02 mg/mL. Compared with control group, serum BUN, SCr and MDA in renal tissue were significantly increased in PQ group, and the protein, GSH contents and SOD activity were significantly decreased [BUN (mmol/L): 40.80±2.49 vs. 13.67±1.58, SCr (μmol/L): 163.46±8.67 vs. 51.80±4.37, MDA (nmol/g): 7.51±0.23 vs. 4.52±0.33, protein (μmol/L): 0.94±0.14 vs. 1.35±0.10, GSH (mg/g): 1.08±0.48 vs. 3.30±0.44, SOD (kU/L): 70.74±6.42 vs. 112.89±8.72, allP 0.05).Conclusion HMH can protect the kidney against PQ-induced nephrotoxicity, and the mechanism of which maybe attributed to its anti-oxidation property and ability to scavenge hydroxyl radical.
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<p><b>OBJECTIVE</b>To evaluate the influence of an extract of Genista tinctoria L. herba (GT) or methylparaben (MP) on histopathological changes and 2 biomarkers of oxidative stress in rats subchronicly exposed to bisphenol A (BPA).</p><p><b>METHODS</b>Adult female Wistar rats were orally exposed for 90 d to BPA (50 mg/kg), BPA+GT (35 mg isoflavones/kg) or BPA+MP (250 mg/kg). Plasma and tissue samples were taken from liver, kidney, thyroid, uterus, ovary, and mammary gland after 30, 60, and 90 d of exposure respectively. Lipid peroxidation and in vivo hydroxyl radical production were evaluated by histological analysis along with malondialdehyde and 2,3-dihydroxybenzoic acid detection.</p><p><b>RESULTS</b>The severity of histopathological changes in liver and kidneys was lower after GT treatment than after BPA or BPA+MP treatment. A minimal thyroid receptor antagonist effect was only observed after BPA+MP treatment. The abnormal folliculogenesis increased in a time-dependent manner, and the number of corpus luteum decreased. No significant histological alterations were found in the uterus. The mammary gland displayed specific estrogen stimulation changes at all periods. Both MP and GT revealed antioxidant properties reducing lipid peroxidation and BPA-induced hydroxyl radical generation.</p><p><b>CONCLUSION</b>GT L. extract ameliorates the toxic effects of BPA and is proved to have antioxidant potential and antitoxic effect. MP has antioxidant properties, but has either no effect or exacerbates the BPA-induced histopathological changes.</p>
Subject(s)
Animals , Female , Rats , Benzhydryl Compounds , Toxicity , Chemical and Drug Induced Liver Injury , Pathology , Endocrine Disruptors , Toxicity , Genista , Hydroxyl Radical , Blood , Lipid Peroxidation , Liver , Pathology , Oxidative Stress , Parabens , Toxicity , Phenols , Toxicity , Phytotherapy , Plant Extracts , Pharmacology , Therapeutic Uses , Rats, WistarABSTRACT
The antioxidant potential of nerolidol against the formation of thiobarbituric acid reactive substances (TBARS), hydroxyl radical and nitric oxide production was assessed in this study. At concentrations of 0.9, 1.8, 3.6, 5.4 and 7.2 mg/mL, it was observed that nerolidol prevented lipid peroxidation induced by 2,2?-azobis-2-amidinopropane (AAPH), inhibiting the formation of TBARS in a manner similar to that of Trolox, a synthetic hydrophilic ?-tocopherol analog that is widely used as an antioxidant standard. Nerolidol also reduced the production of the hydroxyl radical and nitric oxide, possibly indicating an in-vitro antioxidant property. This property could be exploited to protect in-vivo molecular targets (DNA, lipids, carbohydrates and proteins). Although nerolidol exhibited in-vitro antioxidant activity, by its capacity to remove hydroxyl radicals and nitric oxide and to prevent the formation of TBARS, more research is needed to characterize better the antioxidant potential of this compound.
O presente estudo avaliou o potencial antioxidante do nerolidol contra a formação de substâncias reativas ao ácido tiobarbitúrico (TBARS), radical hidroxila e produção de óxido nítrico. Nas concentrações de 0,9, 1,8, 3,6, 5,4 e 7,2 ?g/mL foi observado que o nerolidol preveniu a peroxidação lipídica induzida por 2,2?-azobis-2-amidinopropano(AAPH), inibindo a quantidade de TBARS formado, de maneira semelhante ao composto Trolox, um análogo sintético hidrofílico do ?-tocoferol, que é muito utilizado como padrão antioxidante. Além disso, o nerolidol também reduziu a produção do radical hidroxila, assim como a produção de óxido nítrico, possivelmente devido a uma propriedade antioxidante in vitro, que pode ser explorada para a proteção in vivo de alvos moleculares (DNA, lipídios, carboidratos e proteínas). O nerolidol apresentou potencial antioxidante in vitro, por meio da capacidade de remoção de radicais hidroxilas e do óxido nítrico, bem como na prevenção da formação de TBARS. No entanto, mais estudos são necessários para caracterizar melhor o potencial antioxidante in vitro deste composto
Subject(s)
Antioxidants , Hydroxyl Radical , Lipid Peroxidation , Nitric OxideABSTRACT
Objective: To study the prevention and rehabilitation of Shengxue Pills on liver, spleen, bone marrow cells, peripheral blood lymphocyte of mice injured by low-dose radiation and their mechanisms. Methods: Mice were randomly divided into five groups: control, Shengxue Pills prevention, Shengxue Pills rehabilitation, model 1 (corresponding to rehabilitation), and model 2 (corresponding to prevention) groups. Using the ELISA method to detect the activity of hydroxyl radical, superoxide anion radical, and ornithine decarboxylase (ODC) in liver and spleen cells. The bone marrow cells and peripheral lymphocyte micronucleus rate were observed under high power lens. Results: Compared with control group, the amounts of hydroxyl radical and superoxide anion radical in the two model groups were obviously increased. Compared with the corresponding model groups, the above indexes in prevention group and rehabilitation group were significantly decreased. Compared with the control group, the activity of ODC in mice of the two model groups was obviously enhanced, but bone marrow cells and peripheral lymphocyte micronucleus rate were increased. Compared with the corresponding model groups, the activity of ODC in mice of prevention and rehabilitation groups was weakened, and bone marrow cells and peripheral lymphocyte micronucleus rate were decreased. But each index of spleen cells showed no significant difference. Conclusion: Shengxue Pills could effectively prevent and rehabilitate the damage in liver cells, peripheral blood lymphocytes, and bone marrow cells of mice injured by low-dose radiation.
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O presente estudo avaliou o potencial antioxidante in vitro da ciano-carvona contra a formação de substâncias reativas com o ácido tiobarbitúrico (TBARS), radical hidroxila e produção de óxido nítrico. Observou-se que a ciano-carvona (0,9, 1,8, 3,6, 5,4 e 7,2 μg/mL), foi capaz de prevenir a peroxidação lipídica induzida por 2,2'-azobis-2-amidinopropano (AAPH), inibindo a quantidade de TBARS formada. Resultado semelhante foi obtido com o Trolox (140 μg/mL), um análogo sintético hidrofílico do α-tocoferol, que é largamente usado como padrão antioxidante. Este resultado sugere que a ciano-carvona pode exercer um efeito antioxidante contra a peroxidação lipídica in vivo. A ciano-carvona também produziu uma remoção do radical hidroxila, sugerindo uma possível capacidade de proteção contra danos celulares in vitro produzidos por este radical. O Trolox também reduziu significativamente a quantidade deste radical. Em relação à produção de óxido nítrico, foi detectado uma diminuição significativa na produção deste composto pela ciano-carvona, demonstrando uma propriedade antioxidante in vitro, um achado que pode ser explorado para a proteção in vivo das biomoléculas, como lipídios da membrana celular. A ciano-carvona revelou potencial antioxidante in vitro, por meio da capacidade de remoção contra radicais hidroxilas e do óxido nítrico, bem como preveniu a formação de TBARS.
The in vitro antioxidant potential of the monoterpene cyano-carvone was tested against the formation of thiobarbituric acid reactive substances (TBARS) and production of hydroxyl radical and nitric oxide. It was observed that cyano-carvone (0.9, 1.8, 3.6, 5.4 and 7.2 μg/mL) was capable of reducing lipid peroxidation induced by 2,2'-azobis-2-amidinopropane (AAPH), thus inhibiting TBARS generation. Similar results were obtained with Trolox (140 μg/mL), a synthetic analogue of the hydrophilic α-tocopherol, which is widely used as an antioxidant standard. This result suggests that cyano-carvone may exert an antioxidant effect against lipid peroxidation in vivo. Cyano-carvone also led to removal of the hydroxyl radical, indicating a potential ability to protect against in vitro cell damage produced by this radical. Trolox also reduced significantly the amount of this radical. Regarding nitric oxide production, this was significantly lowered by cyano-carvone, demonstrating an antioxidant property in vitro, which could be exploited in vivo to protect biomolecules such as lipids of the cell membrane. In sum, cyano-carvone showed an in vitro antioxidant potential, by its capacity to remove hydroxyl radicals and nitric oxide, and prevented TBARS formation.
Subject(s)
Antioxidants , Hydroxyl Radical , Lipid Peroxidation , Monoterpenes , Nitric Oxide , Oils, VolatileABSTRACT
The methanolic extract of Musa ABB cv Pisang Awak was investigated for the polyphenolic contents and antioxidant activity. The total phenol and flavonoid contents of the fruit extract were found to be 120 mg gallic acid equivalents (GAE) and 440 mg quercetin equivalents (QE)/100 g of sample dry weight, respectively. The antioxidant activity of the Pisang Awak methanol extract (PAME) (20-500 µg/ml) was determined using 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, reducing capacity, 2-2’-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) radical cation decolourization and hydroxyl radical scavenging capacity (OH·). The EC50 values of DPPH, ABTS and OH· activities of the PAME and butylated hydroxy toluene (BHT) were found to be 65 and 9 µg/ml, 29 and 6 µg/ml, 36 and 42 µg/ml respectively. The reducing capacity increased with increasing concentration (31.5-1000 mg/ml) of the fruit extract and the activity was comparable with the standard BHT. The high performance thin layer chromatography (HPTLC) analysis of the extract revealed the presence of polyphenols. The strong and positive correlations were obtained between total phenol/flavonoid contents (R2 = 0.693-1.0) and free radical scavenging ability was attributed to the polyphenols as the major antioxidants.
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Free Radical Scavengers/chemistry , Free Radicals/chemistry , Iron/chemistry , Musa/chemistry , Phenols/analysis , Plant Extracts/chemistryABSTRACT
Introducción: el agente causal de la ulceración gástrica está asociado al desequilibrio entre factores agresivos y defensivos que actúan sobre la mucosa gástrica. El D-002, mezcla de seis alcoholes alifáticos primarios superiores purificada de la cera de abejas, produce efectos gastroprotectores mediados por múltiples mecanismos y reducción de la peroxidación lipídica en la mucosa gástrica. Objetivo: determinar si el D-002 es capaz de capturar el radical hidroxilo añadido in vitro o generado in vivo en ratas con úlcera gástrica inducida por indometacina. Métodos: En la experiencia in vitro el D-002 se añadió a concentraciones entre 0,9 y 1 000 mg/mL. En la experiencia in vivo las ratas se distribuyeron en seis grupos: un control negativo y cinco que recibieron indometacina: un control positivo tratado con el vehículo, tres con D-002 (5, 25, y 100 mg/kg, respectivamente, p.o.) y otro con omeprazol (20 mg/kg i.p.). Los tratamientos se administraron una hora (vehículo y D-002) o 30 min (omeprazol), respectivamente, antes de inducir las úlceras. En ambas experiencias se tomaron alícuotas de mucosa gástrica, y se determinó el daño a la 2-desoxirribosa por el radical hidroxilo. Resultados: la administración oral del D-002, no in vitro, protegió a la 2-desoxirribosa del daño oxidativo de modo marcado, significativo y dependiente de la dosis con respecto al control positivo. Conclusiones: los resultados indican que la capacidad del D-002 (25 y 100 mg/kg) administrado por vía oral para secuestrar el radical hidroxilo, generado en la mucosa gástrica por la indometacina, pudiera contribuir a sus efectos antioxidantes y gastroprotectores sobre el daño que los antiinflamatorios no esteroideos producen sobre la mucosa gástrica.
Introduction: the etiology of the gastric ulceration is associated to the imbalance between aggressive and defensive factors acting upon the gastric mucosa. D-002, a mixture of 6 higher primary alcohols purified from the beeswax, cause some multiple mechanism-mediated gastroprotective effects and decrease of lipid peroxidation in the gastric mucosa. Objective: to determine whether D-002 can scavenge the in vivo added or in vivo generated hydroxyl radical in rats with indometacin-induced gastric ulcer or not. Methods: For the in vitro experiment, D-002 was added at concentrations 0.9 and 1 000 mg/mL For the in vivo experiment, the rats were randomized into 6 groups: one negative control, and five indometacin-treated groups as follows a positive excipient-treated control, three under D-002 treatment (5, 25 or 100 mg/kg, respectively, p.o.), and another group treated with Omeprazole (20 mg/kg i.p.). These lines of treatment were given 1 hour (excipient and D-002) or 30 min (Omeprazole) prior to inducing the ulcers. In both experiments, aliquots from the gastric mucosa were taken and the damage infringed to 2-deoxiribose by the hydroxyl radical was determined. Results: oral administration of D-002, rather than in vitro addition, significantly protected 2-desoxiribose from the oxidative damage depending on the dosage as compared to the positive control. Conclusions: these results indicate that the ability of the orally administered D-002 (25 and 100 mg/kg) to scavenge the hydroxyl radical endogenously generated on the gastric mucosa by indometacin could contribute to its antioxidant and gastroprotective effects against the damage that the non-steroidal anti-inflammatory drugs carry to the gastric mucosa.
Subject(s)
Alcohols , Hydroxyl Radical , Indomethacin/adverse effects , Gastric Mucosa/injuries , Stomach Ulcer/chemically inducedABSTRACT
OBJECTIVE: To examine the effects of echinacoside (ECH) on striatal extracellular levels of hydroxyl radical in cerebral ischemia rats and its possible mechanism of anti-cerebral ischemia. METHODS: Rats were divided into control, model, ECH high and low dose and CXQ groups randomly. Every rat was administered drugs or vehicle through intraperitoneal injection, one time a day for 7 consecutive days. At day 3, focal ischemia was generated by permanent middle cerebral artery occlusion (MCAO). Then the striatal extracellular fluids were gained by brain microdialysis. High performance liquid chromatography with electrochemical detection was used to measure the striatal extracellular levels of hydroxyl radicals. RESULTS: The levels of 2, 3-DHBA, 2, 5-DHBA increased rapidly. Compared with the model group, administration of ECH of high and low dose (30, 15 mg · kg-1 · d-1) and CXQ (30 mg · kg-1 · d-1) successfully prevented the elevation of 2, 3-DHBA and 2, 5-DHBA. CONCLUSION: ECH can reduce striatal extracellular levels of hydroxyl radical, which may be one of its mechanisms of anti-cerebral ischemia. Copyright 2012 by the Chinese Pharmaceutical Association.
ABSTRACT
Baicalein (5, 6, 7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one), a naturally occurring flavone present in some of the medicinal plants is known for its potential therapeutic effects, such as cardioprotective, anticancer and anti-inflammatory properties. However, detailed role and mechanisms behind its protective properties against different generators for oxidative stress have not been examined. In the present study, we investigated the possible protective ability of baicalein against the membrane damage caused by reactive oxygen species (ROS) and reactive nitrogen species (RNS) and the mechanisms involved using pulse radiolysis technique. Baicalein offered efficient protection even at a concentration of 10 M towards membrane damage caused by lipid peroxidation induced by the -radiation, peroxyl radicals, ascorbate-Fe2+ and peroxynitrite in rat liver mitochondria and heart homogenate. To elucidate its reaction mechanisms with biologically relevant radicals, transient absorption spectroscopy employing pulse radiolysis technique was used. Baicalein showed fairly high rate constants (3.7 × 109, 1.3 × 109 and 8.0 × 108 dm3 mol-1 s-1 for hydroxyl, azidyl and alkylchloroperoxyl radicals, respectively), suggesting that baicalein can act as an effective scavenger of these radicals. In each case, the phenoxyl radical of baicalein was generated. Thus, it was evident that the phenolic moiety of baicalein was responsible for the free radical scavenging process. Baicalein also reacts with linoleic acid peroxyl radical (LOO·), indicating its ability to act as a chain breaking antioxidant. Peroxynitrite-mediated radicals were shown to be reactive towards baicalein and the bimolecular rate constants were 2.5 × 107 and 3 × 108 dm3 mol-1 s-1 for ·NO2 and CO3·- radicals, respectively. In conclusion, our results revealed the potential of baicalein in protecting mitochondrial membrane against oxidative damage induced by the four different agents. We propose that the protective effect is mediated via scavenging of primary and secondary radicals generated during oxidative stress.
Subject(s)
Animals , Cell Membrane/drug effects , Female , Flavanones/chemistry , Flavanones/pharmacology , Free Radicals , Heart/drug effects , Mitochondria, Liver/drug effects , Rats , Rats, Wistar , Reactive Oxygen Species/metabolismABSTRACT
Metallothioneins (MTs), a low-mass class of metalloproteins, are characterized by a high thiolate sulphur and metal content. MTs are involved in metal homeostasis and heavy metal detoxification, and are efficient scavengers of free radicals. This article describes zinc release from human MT-1 and modification of its amino acid composition when subjected to free radicals generated during gamma ray radiolysis. The effect of gamma ray radiolysis of untreated and metal-depleted human MT-1 was tested under multiple aerobic and anaerobic conditions at increasing irradiation doses. Under all conditions, a rapid increase of serine in the early stages of irradiation was observed. Irradiation for longer times led to cysteic acid formation, except under argon atmosphere. Several other amino acid concentrations gradually decreased. Formation of limited amounts of hydroxyproline, hydroxylysine and ornithine as well as some less common derivatives such as cystathionine occurred as side-effects.
ABSTRACT
This study demonstrated that the bacteria could adsorb Fe3+ and reduce Fe3+ to Fe2+. Iron had significant bacteriostatic effects, which were directly proportional to the iron concentration and under the influence of pH and chelator. It presumed that the inhibition of Fe3+ acts through the formation of hydroxyl free radicals.
Subject(s)
Anti-Bacterial Agents/analysis , Iron Bacteria/analysis , Ions/analysis , Iron Chelating Agents/analysis , Siderophores/analysis , Methods , MethodsABSTRACT
El uso de la miel en medicina tradicional y complementaria/alternativa necesita evidencias para explicar las características bioactivas de este producto de la colmena. Las técnicas analíticas sugeridas por la Comisión del Codex Alimentarius para la inocuidad y los propósitos del control de calidad y de comercialización, no son suficientes para diferenciar este complejo producto de las abejas, aparentemente homogéneo. En este trabajo se midió la capacidad antioxidante de la miel producida por los géneros Apis, Melipona y Trigona de Venezuela, utilizando tres sistemas oxidativos, para probar la eficacia de la miel en la inhibición del anión del superóxido (O2●-), la formación del radical hidroxilo (OH●) y la degradación del benzoato (AOA). Todas las muestras de miel genuina diluida presentaron indicadores antioxidantes más altos que los de la miel artificial y del ácido lipoico utilizado como control antioxidante suave. Sin embargo, la melatonina y la quercetina, los controles antioxidantes potentes usados aquí, fueron mejores limpiadores que las mieles genuinas en los análisis de OH● y del AOA, que son sistemas generadores de radicales hidroxilo. Ésta es la primera vez que se utiliza AOA para determinar la capacidad antioxidante de la miel. Además de su uso para medir características bioactivas, los indicadores de capacidad antioxidante aquí usados podrían proponerse en como análisis para controlar la miel adulterada. El origen entomológico no se relacionó con las características antioxidantes de la miel.
The use of honey in traditional and complementary/alternative medicine needs evidence to explain the bioactive properties of this product from the hive. The analytical techniques of the Codex Alimentarius Commission for safety and trading quality control purposes, are not sufficient to differentiate this apparently homogeneus but complex bee product. In this work, the antioxidant capacity of Apis, Melipona and Trigona honey from Venezuela, was measured within three oxidative systems, to test the effectiveness of honey at scavenging superoxide anion (O2●-) formation, hydroxyl radical (OH●) formation and benzoate degradation (AOA). All the diluted genuine honey samples showed higher antioxidant capacity indicators than those of artificial honey and the mild antioxidant control lipoic acid. However, melatonin and quercetin, the potent antioxidant controls used here, were better scavengers than genuine honeys in the OH● and the AOA assays, which are hydroxyl radical generating systems. This is the first time that AOA is used to determine the honey antioxidant capacity. Besides its use to measure bioactive properties, the antioxidant capacity indicators used here could also become a test to control adulterated honey. The entomological origin was not related to the antioxidant properties of honey.