Interaction between ascorbic acid and gallic acid in a model of fructose-mediated protein glycation and oxidation

Background: Dietary plant-based foods contain combinations of various bioactive compounds such as phytochemical compounds and vitamins. The combined effect of these vitamins and phytochemicals remains unknown, especially in the prevention of diabetes and its complications. The present study aimed to investigate the combined effect of ascorbic acid and gallic acid on fructose-induced protein glycation and oxidation. Results: Ascorbic acid (15 µg/mL) and gallic acid (0.1 µg/mL) reduced fructose-induced formation of advanced glycation end products (AGEs) in bovine serum albumin (BSA; 10 mg/mL) by 15.06% and 37.83%, respectively. The combination of ascorbic acid and gallic acid demonstrated additive inhibition on the formation of AGEs after 2 weeks of incubation. In addition, synergistic inhibition on the formation of amyloid cross-ß structure and protein carbonyl content in fructose-glycated BSA was observed. At the same concentration, the combination of ascorbic acid and gallic acid produced a significant additive effect on the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. Conclusion: Combining natural compounds such as ascorbic acid and gallic acid seems to be a promising strategy to prevent the formation of AGEs.

Over-expression of dehydroascorbate reductase enhances oxidative stress tolerance in tobacco

Background: Ascorbic acid (Asc) is one of the most abundant antioxidants and it serves as a major contributor to protect plants against oxidative damage. Plants use two enzymes that participate in the metabolic recycling of Asc. One of these two enzymes is dehydroascorbate reductase (DHAR). It directly regenerates Asc from its oxidized state and thus prevents Asc from being irreversibly hydrolyzed to 2, 3-diketogulonic acid. This study aimed to examine whether over-expression of DHAR leads to an enhanced oxidative stress tolerance in tobacco plants. Results: In this study, we functionally characterized a novel JcDHAR gene from Jatropha curcas and found via quantitative RT-PCR analysis that JcDHAR can be induced with H2O2, salt and PEG stresses. The DHAR activities of transgenic tobacco plants increased from 2.0 to 5.3 fold compared to wild-type plants. As a result, the transgenic plants displayed enhanced tolerance to oxidative stress. Conclusions: Our results indicate that JcDHAR expression can effectively enhance the tolerance to oxidative stress in plants.

Association of socioeconomic stratification with plasmatic markers of lipoperoxidation and antioxidants in Venezuelan school-age children / Asociacion de la estratificacion socioeconomica con marcadores plasmaticos de lipoperoxidacion y antioxidantes en escolares venezolanos

Abstract Objetive: To establish association between socioeconomic status and plasmatic markers of lipoperoxidation and antioxidants in Venezuelan school-age children from the middle-class and in critical poverty. Methods: Cross-sectional study with a sample of 114 school-age children (aged 7-9). The socioeconomic status, dietary intake of macro and micro-nutrients, weight, height, lipid profile, indicators of lipid peroxidation and enzymatic and non-enzymatic antioxidants were determined. Results: The daily average intake of energy, carbohydrates and vitamin A, and the percentage of energy obtained from carbohydrates was significantly higher in middle-class children compared to critical poverty children (p <0.05). The circulating oxidized low density lipoprotein (p <0.001) and the susceptibility of low density lipoproteins and very low density lipoproteins to oxidation in vitro (p <0.05) were significantly higher in middle-class children, while the critical poverty children showed significantly lower levels of Vitamin C and E in plasma (p <0.05). Non-enzymatic antioxidant levels were frequently deficient in both strata. The concentrations of circulating oxidized low density lipoprotein (OR: 1.09, CI 95%: 1.016-1.179; p= 0.017) and Vitamin C (OR: 3.21, CI 95%: 1.104-9.938; p= 0.032) were associated to the socioeconomic status independently of gender, family history of premature coronary artery disease, triglicerides, Vitamin C and E dietary intake and count of white blood cells. Conclusion: The socioeconomic status was associated to circulating oxidized low density lipoprotein and Vitamin C in Venezuelan school-age children, The results suggested the need to improve the dietary intake of antioxidants in both studied socioeconomic groups.

Resumen Objetivo: Establecer la asociación entre la estratificación socioeconómica y marcadores plasmáticos de lipoperoxidación y antioxidantes en escolares venezolanos de clase media y en pobreza crítica. Métodos: Estudio transversal de 114 escolares con edades entre 7 y 9 años. Se determinó el estrato socioeconómico, la ingesta dietaria de macro y micronutrientes, peso, talla, perfil lipídico e indicadores plasmáticos de peroxidacion lipídica y antioxidantes enzimáticos y no-enzimáticos. Resultados: La ingesta dietaria promedio de energía, carbohidratos y vitamina A así como el porcentaje de energía obtenida de los carbohidratos fueron significativamente más elevados en los niños de clase media comparados con los niños en pobreza crítica (p <0.05). La concentración de lipoproteína de baja densidad oxidada circulante y la susceptibilidad de las lipoproteínas de baja densidad y muy baja densidad a la oxidación in vitro (p <0.05) fueron significativamente más elevadas en los niños de clase media, mientras los niños en pobreza crítica demostraron niveles plasmáticos de vitamin C y E significativamente más bajos (p <0.05). Las frecuencia de déficit de antioxidantes no enzimáticos fue elevada en ambos grupos estudiados. Las concentraciones de lipoproteína de baja densidad oxidada circulante (OR: 1.09, IC 95%: 1.016-1.179; p= 0.017) y vitamina C (OR: 3.21, IC 95%: 1.104-9.938; p= 0.032) se asociaron significativamente al estrato socioeconómico independientemente del sexo, historia familiar de enfermedad coronaria prematura, triglicéridos, ingesta dietaria de vitaminas C y E y contaje total de glóbulos blancos. Conclusión: La estratificación socioeconómica se asoció a las concentraciones de lipoproteína de baja densidad oxidada circulante y vitamina C en escolares venezolanos, los resultados sugirieron la necesidad de mejorar la ingesta dietaria de antioxidantes en ambos estratos socioeconómicos estudiados.

Acute Ethanol Intake Induces NAD(P)H Oxidase Activation and Rhoa Translocation in Resistance Arteries / O consumo agudo de etanol induz a ativação da NAD(P)H oxidase e translocação da RhoA em artérias de resistência

Abstract Background: The mechanism underlying the vascular dysfunction induced by ethanol is not totally understood. Identification of biochemical/molecular mechanisms that could explain such effects is warranted. Objective: To investigate whether acute ethanol intake activates the vascular RhoA/Rho kinase pathway in resistance arteries and the role of NAD(P)H oxidase-derived reactive oxygen species (ROS) on such response. We also evaluated the requirement of p47phox translocation for ethanol-induced NAD(P)H oxidase activation. Methods: Male Wistar rats were orally treated with ethanol (1g/kg, p.o. gavage) or water (control). Some rats were treated with vitamin C (250 mg/kg, p.o. gavage, 5 days) before administration of water or ethanol. The mesenteric arterial bed (MAB) was collected 30 min after ethanol administration. Results: Vitamin C prevented ethanol-induced increase in superoxide anion (O2-) generation and lipoperoxidation in the MAB. Catalase and superoxide dismutase activities and the reduced glutathione, nitrate and hydrogen peroxide (H2O2) levels were not affected by ethanol. Vitamin C and 4-methylpyrazole prevented the increase on O2- generation induced by ethanol in cultured MAB vascular smooth muscle cells. Ethanol had no effect on phosphorylation levels of protein kinase B (Akt) and eNOS (Ser1177 or Thr495 residues) or MAB vascular reactivity. Vitamin C prevented ethanol-induced increase in the membrane: cytosol fraction ratio of p47phox and RhoA expression in the rat MAB. Conclusion: Acute ethanol intake induces activation of the RhoA/Rho kinase pathway by a mechanism that involves ROS generation. In resistance arteries, ethanol activates NAD(P)H oxidase by inducing p47phox translocation by a redox-sensitive mechanism.

Resumo Fundamento: O mecanismo da disfunção vascular induzido pelo consumo de etanol não é totalmente compreendido. Justifica-se, assim a identificação de mecanismos bioquímicos e moleculares que poderiam explicar tais efeitos. Objetivos: Investigar se a ingestão aguda de etanol ativa a via vascular RhoA/Rho quinase em artérias de resistência e o papel das espécies reativas de oxigênio (ERO) derivadas da NAD(P)H oxidase nessa resposta. Nós também avaliamos se ocorreu translocação da p47phox e ativação da NAD(P)H oxidase após o consumo agudo de etanol. Métodos: Ratos Wistar machos foram tratados com etanol via oral (1g/kg, p.o. gavagem) ou água (controle). Alguns ratos foram tratados com vitamina C (250 mg/kg, p.o. gavagem, 5 dias) antes de água ou etanol. O leito arterial mesentérico (LAM) foi coleado 30 min após a administração de etanol. Resultados: A vitamina C preveniu o aumento da geração de ânion superóxido (O2 -) e lipoperoxidação no LAM induzidos pelo etanol. A atividade da catalase (CAT), da superóxido dismutase (SOD) e os níveis de glutationa reduzida(GSH), nitrato e peróxido de hidrogênio (H2O2) não foram afetados após a ingestão aguda de etanol. A vitamina C e o 4-metilpirazol preveniram o aumento na geração de O2 - induzido pelo etanol em cultura de células do músculo liso vascular (CMLV). O etanol não afetou a fosforilação da proteína quinase B (Akt) e nem da óxido nítrico sintase endotelial (eNOS) (nos resíduos de Ser1177 ou Thr495) ou a reatividade vascular do LAM. A vitamina C preveniu o aumento da razão membrana:citosol da p47phox e a expressão da RhoA no LAM de rato induzido pelo etanol. Conclusão: A ingestão aguda de etanol induz a ativação da via RhoA/Rho quinase por um mecanismo que envolve a geração de ERO. Nas artérias de resistência, o etanol ativa NAD(P)H oxidase induzindo a translocação da p47phox por um mecanismo redox-sensível.

Effects of aroma quality on the biotransformation of natural 2-phenylethanol produced using ascorbic acid

Background Natural 2-phenylethanol (2-PE) is an important flavoring that emits the aroma of roses. During biotransformation, the aroma quality of natural 2-PE is affected by its main by-products, which include butanol, isobutyric acid, butyric acid, and isovaleric acid. Thus, controlling undesirable by-product formation can reduce the effect of odor on 2-PE aroma quality. Results 2-PE was produced through biotransformation using l-phenylalanine as a substrate and glucose as a carbon source. Ascorbic acid was added to the system to improve the redox reaction and suppress the generation of by-products. Principal component analysis of the aroma quality of 2-PE was performed using an electronic nose. Similarity analysis revealed that the effects of four by-products on 2-PE aroma quality may be ranked in the following order: isovaleric acid > butyric acid > isobutyric acid > butanol. The sample that exhibited the best similarity to the standard 2-PE sample (99.19%) was the sample to which ascorbic acid had been added during glucose metabolism. Conclusions 2-PE produced through the addition of ascorbic acid exhibited the closest aroma similarity to the standard 2-PE sample.

The effect of weight reduction on antioxidant enzymes and their association with dietary intake of vitamins A, C and E / Efeito da redução de peso sobre as enzimas antioxidantes e associação destas com a ingestão de vitaminas A, C e E

Objective Our goal was to assess the effects of weight loss on antioxidant enzymes of red blood cells and it’s relation with vitamins A, E and C intake in 30 obese women. Subjects and methods General information, anthropometric measurements, 3-day food recall, and fasting blood samples were collected from 30 obese women at the beginning of the study and after 3 months intervention. Weight loss was set at about 10% of their weight before the intervention. Results Glutathione reductase and catalase activities showed a significant increase (P < 0.01) after weight reduction, but no significant changes were seen in the superoxide dismutase and glutathione peroxidase activities. There was a positive linear correlation between daily vitamin C intake with superoxide dismutase enzyme after intervention (P = 0.004, r = 0.507). There was a negative linear correlation between vitamin E intake and glutathione peroxidase activity before intervention (P = 0.005, r = -0.5). A negative correlation was found between daily vitamin A intake and glutathione reductase enzyme before and after intervention (r = -0.385, r = -0.397, P < 0.05) respectively. No significant correlation was observed between vitamins A, C, E amounts and catalase activity. Conclusions Ten percent weight reduction can have a significant role in increasing antioxidant enzymes activities, especially glutathione reductase, and catalase enzymes in obese women. However, it is important to take into consideration a balanced amount of certain nutrients while administering a diet with limited energy. .

Objetivo Nosso objetivo foi avaliar os efeitos da perda de peso sobre as enzimas antioxidantes de eritrócitos, e a relação destas com a ingestão das vitaminas A, E e C. Sujeitos e métodos Foram coletadas informações gerais e medidas antropométricas, registro alimentar de três dias e amostras de sangue em jejum de 30 mulheres obesas no início do estudo e depois de três meses da intervenção. A perda de peso determinada antes da intervenção foi de 10% do peso. Resultados As atividades da glutationa redutase e da catalase mostraram aumento significativo (P < 0,01) depois da perda de peso, mas não houve mudanças significativas nas atividades da superóxido dismutase e da glutationa peroxidase. Foi observada uma correlação linear positiva entre a ingestão diária de vitamina C e a enzima superóxido dismutase após a intervenção (P = 0,004, r = 0,507). Houve uma correlação linear negativa entre a ingestão de vitamina E e a atividade da glutationa peroxidase antes da intervenção (P = 0,005, r = -0,5). Foi observada uma correlação negativa entre a ingestão diária de vitamina A e a enzima glutationa redutase antes e depois da intervenção (r = -0,385, r = -0,397, P < 0,05), respectivamente. Não foram observadas correlações significativas entre as vitaminas A, C, E e os níveis e a atividade da catalase. Conclusões Uma redução de 10% no peso pode ter um papel significativo no aumento da atividade das enzimas antioxidantes, especialmente na glutationa redutase e catalase em mulheres obesas. Entretanto, é importante levar em consideração uma ingestão equilibrada de certos nutrientes ao se recomendar uma dieta com níveis de energia restritos. .

Chlorambucil and ascorbic acid-mediated anticancer activity and hematological toxicity in Dalton's ascites lymphoma-bearing mice.

Chlorambucil is an anticancer drug with alkylating and immunosuppressive activities. Considering various reports on the possible antioxidant/protective functions of ascorbic acid (vitamin C), it was aimed at to explore the modulatory effect of ascorbic acid on therapeutic efficacy and toxicity induced by chlorambucil. Dalton’s ascites lymphoma tumor serially maintained in Swiss albino mice were used for the present experiments. The result of antitumor activity showed that combination treatment with ascorbic acid and chlorambucil exhibited enhanced antitumor activity with 170% increase in life span (ILS), which is significantly higher as compared to chlorambucil alone (ILS 140%). Analysis of apoptosis in Dalton’s lymphoma tumor cells revealed a significantly higher apoptotic index after combination treatment as compared to chlorambucil alone. Blood hemoglobin content, erythrocytes and leukocytes counts were decreased after chlorambucil treatment, however, overall recovery in these hematological values was noted after combination treatment. Chlorambucil treatment also caused morphological abnormalities in red blood cells, majority of which include acanthocytes, burr and microcystis. Combination treatment of mice with ascorbic acid plus chlorambucil showed less histopathological changes in kidney as compared to chlorambucil treatment alone, thus, ascorbic acid is effective in reducing chlorambucil-induced renal toxicity in the hosts. Based on the results, for further devel­opment, hopefully into the clinical usage, the administration of ascorbic acid in combination with chlorambucil may be recommended.

Differential antioxidative response of tolerant and sensitive maize (Zea mays L.) genotypes to drought stress at reproductive stage.

The role of oxidative stress management was evaluated in two maize (Zea mays L.) genotypes — Parkash (drought-resistant) and Paras (drought-sensitive), subjected to drought stress during reproductive stage. Alterations in their antioxidant pools — glutathione (GSH) and ascorbic acid (AsA) combined with activities of enzymes glutathione reductase (GR), ascorbate peroxidase (APX), peroxidase (POX) and catalase (CAT) involved in defense against oxidative stress and stress parameters, namely chlorophyll (Chl), hydrogen peroxide (H2O2) and malondialdehyde (MDA) were investigated in flag leaves from silk emergence till maturity. The drought caused transient increase in GR, APX, POX and CAT activities in drought-tolerant genotype (Parkash) which decreased at later stages with the extended period of drought stress. However, in Paras, drought stress caused decrease in activities of GR and CAT from initial period of stress till the end of experiment, except for POX which showed slight increase in activity. A significant increase in GSH content was observed in Parkash till 35 days after silking (DAS), whereas in Paras, GSH content remained lower than irrigated till maturity. Parkash which had higher AsA and Chl contents, also showed lower H2O2 and MDA levels than Paras under drought stress conditions. However, at the later stages, decline in antioxidant enzyme activities in Parkash due to severe drought stress led to enhanced membrane damage, as revealed by the accumulation of MDA. Our data indicated that significant activation of antioxidant system in Parkash might be responsible for its drought-tolerant behavior under drought stress and helped it to cope with the stress up to a definite period. Thus, the results indicate that antioxidant status and lipid peroxidation in flag leaves can be used as indices of drought tolerance in maize plants and also as potential biochemical targets for the crop improvement programmes to develop drought-tolerant cultivars.

Individual and interactive effects of elevated carbon dioxide and ozone on tropical wheat (Triticum aestivum L.) cultivars with special emphasis on ROS generation and activation of antioxidant defence system.

The effects of elevated CO2 and O3, singly and in combination were investigated on various physiological, biochemical and yield parameters of two locally grown wheat (Triticum aestivum L.) cultivars (HUW-37 and K-9107) in open top chambers (OTCs). Elevated CO2 stimulated photosynthetic rate (Ps) and Fv/Fm ratio and reduced the stomatal conductance (gs). Reactive oxygen species, lipid peroxidation, anti-oxidative enzymes, ascorbic acid and total phenolics were higher, whereas Ps, gs, Fv/Fm, protein and photosynthetic pigments were reduced in elevated O3 exposure, as compared to their controls. Under elevated CO2 + O3, elevated levels of CO2 modified the plant performance against O3 in both the cultivars. Elevated CO2 caused significant increase in economic yield. Exposure to elevated O3 caused significant reduction in yield and the effect was cultivar-specific. The study concluded that elevated CO2 ameliorated the negative impact of elevated O3 and cultivar HUW-37 was more sensitive to elevated O3 than K-9107.

L-Arginine attenuates oxidative stress condition during cardiomyopathy.

Increased production of oxygen free radicals and decreased oxidant capacity occur in coronary artery diseases (CAD). This pro-oxidant shift in intracellular redox state may induce cell death by either direct cell membrane damage by lipid peroxidation or apoptosis through activation of transcription factors. These changes occur not only in cardiomyocytes, but also in cardiac sympathetic nerves, which are very sensitive to oxidative damage. Patients with heart failure encounter reduced peripheral blood flow at rest, during exercise and in response to endothelium-dependent vasodilators. Current treatments of cardiomyopathy, a degenerative condition of the myocardium frequently associated with heart failure have done little to enhance patient survival. Decreased myocardial contractility and altered regulation of peripheral circulation along with oxidative conditions are important contributors to the symptoms and prognosis of the disease process. Nitric oxide formed from L-arginine (2-amino-5 guanidinovaleric acid) metabolism in endothelial cells contributes to regulation of blood flow under these conditions. L-Arginine is the precursor of nitric oxide, an endogenous messenger molecule involved in a variety of endothelium-mediated physiological effects in the vascular system. In the present study, we investigated the effect of oral administration of L-arginine (3 g/day) on the intracellular redox status of the patients of ischemic cardiomyopathy aged 45-60 yrs. The enzymatic and non-enzymatic antioxidant parameters like superoxide dismutase, catalase, total thiols (TSH) and ascorbic acid along with pro-oxidant parameters, such as xanthine oxidase, as well as index of oxidative stress as protein carbonyl content and malondialdehyde (a marker of lipid peroxidation) were investigated in the plasma and RBC lysate. L-Arginine (3 g/day) administration was found to improve the levels of these parameters in the patients and regulate the blood flow, as evident by the improved blood pressure of the patients. Thus, it is inferred that L-arginine attenuates the oxidative stress conditions along with maintaining the blood pressure rate of patients suffering from cardiomyopathy.

[ study for vitamin C stability in some kinds of baby food]

Due to the biological importance of vitamin C and the high ability of degradation, vitamin C content was studied on 152 samples of three baby food products [wet food, dry food, some fruit juices]. The vitamin C composition of all samples was determined in triplicate, using the method of High Performance Liquid Chromatography HPLC [C18 Colum and UV-Detector and the results were compared with the concentrations which are mentioned on the label of the samples. Vitamin C stability was studied in different samples, by exposing them to the accelerated and long - duration stability tests conditions. In addition to the study of vitamin C stability in different kinds of fruit juices and wet baby food after opening the samples and preserving them in normal conditions [4 [degree sign] c]. The results showed that the concentrations which are mentioned on the label of different samples were true except some of them which showed either increase or decrease in the concentration of vitamin C. And the accelerated stability studies showed that the Vitamin C content declined when the temperature increased and the largest lost was when the samples exposed to the temperature of [40 [degree sign] +/- 2 [degree sign] c], and this content of vitamin C declined when the samples exposed to the sun light at the same temperature [25 [degree sign] +/- 2 [degree sign] c]. And the results showed that Vitamin C content in the samples declined and affected by the time factor when the samples were preserved in the normal conditions [4 [degree sign] c], and this content in the stored and handmade fruit juices and wet baby food declined in large percentage after opening these samples and preserving them in normal conditions [4 [degree sign] c

The effects of pycnogenol on antioxidant enzymes in a mouse model of ozone exposure

BACKGROUND/AIMS: Ozone is an environmentally reactive oxidant, and pycnogenol is a mixture of flavonoid compounds extracted from pine tree bark that have antioxidant activity. We investigated the effects of pycnogenol on reactive nitrogen species, antioxidant responses, and airway responsiveness in BALB/c mice exposed to ozone. METHODS: Antioxidant levels were determined using high performance liquid chromatography with electrochemical detection. Nitric oxide (NO) metabolites in bronchoalveolar lavage (BAL) fluid from BALB/c mice in filtered air and 2 ppm ozone with pycnogenol pretreatment before ozone exposure (n = 6) were quantified colorimetrically using the Griess reaction. RESULTS: Uric acid and ascorbic acid concentrations were significantly higher in BAL fluid following pretreatment with pycnogenol, whereas gamma-tocopherol concentrations were higher in the ozone exposed group but were similar in the ozone and pycnogenol pretreatment groups. Retinol and gamma-tocopherol concentrations tended to increase in the ozone exposure group but were similar in the ozone and pycnogenol pretreatment groups following ozone exposure. Malonylaldehyde concentrations increased in the ozone exposure group but were similar in the ozone and pycnogenol plus ozone groups. The nitrite and total NO metabolite concentrations in BAL fluid, which parallel the in vivo generation of NO in the airways, were significantly greater in the ozone exposed group than the group exposed to filtered air, but decreased with pycnogenol pretreatment. CONCLUSIONS: Pycnogenol may increase levels of antioxidant enzymes and decrease levels of nitrogen species, suggesting that antioxidants minimize the effects of acute ozone exposure via a protective mechanism.

Addition of bone morphogenetic protein type 2 to ascorbate and β-glycerophosphate supplementation did not enhance osteogenic differentiation of human adipose-derived stem cells

Bone morphogenetic protein type 2 (BMP-2) is a potent local factor, which promotes bone formation and has been used as an osteogenic supplement for mesenchymal stem cells. OBJECTIVES: This study evaluated the effect of a recombinant BMP-2 as well as the endogenous BMP-4 and BMP-7 in the osteogenic differentiation of adipose-derived stem cells (ASCs) in medium supplemented with ascorbate and β-glycerophosphate. MATERIAL AND METHODS: Human ASCs were treated with osteogenic medium in the presence (ASCs+OM+BMP-2) or absence (ASCs+OM) of BMP-2. The alkaline phosphatase (ALP) activity was determined and the extracellular matrix mineralization was evaluated by Von Kossa staining and calcium quantification. The expressions of BMP-4, BMP-7, Smad1, Smad4, and phosphorylated Smad1/5/8 were analyzed by western blotting. Relative mRNA expressions of Smad1, BMP receptor type II (BMPR-II), osteonectin, and osteocalcin were evaluated by qPCR. Results: ASCs+OM demonstrated the highest expression of BMP-4 and BMP-7 at days 21 and 7, respectively, the highest levels of BMPR-II mRNA expression at day 28, and the highest levels of Smad1 mRNA at days 14 and 28. ASCs+OM+BMP-2 demonstrated the highest levels of Smad1 mRNA expression at days 1, 7, and 21, the highest expression of Smad1 at day 7, the highest expression of Smad4 at day 14, the highest ALP activity at days 14 and 21, and expression of phosphorylated Smad1/5/8 at day 7. ASCs+OM and ASCs+OM+BMP2 showed similar ALP activity at days 7 and 28, similar osteonectin and osteocalcin mRNA expression at all time periods, and similar calcium depositions at all time periods. CONCLUSIONS: We concluded that human ASCs expressed endogenous BMP-4 and BMP-7. Moreover, the supplementation of ASCs with BMP-2 did not increase the level of osteogenic markers in the initial (ALP activity), intermediate (osteonectin and osteocalcin), or final (calcium deposition) phases, suggesting that the exogenous addition of BMP-2 did not improve the in vitro osteogenesis process of human ASCs.

Total antioxidant capacity in Eales’ disease, uveitis & cataract.

Background & objectives: The human system possesses antioxidants that act harmoniously to neutralize the harmful oxidants. This study was aimed to evaluate the serum total antioxidant capacity (TAC) as a single parameter in Eales’ disease (ED) and in an acute inflammatory condition such as uveitis and in cataract which is chronic, compared to healthy controls. Methods: The TAC assay was done spectrophotometrically in the serum of Eales’ disease cases (n=20) as well as in other ocular pathologies involving oxidative stress namely, uveitis and cataract (n=20 each). The oxidative stress measured in terms of TBARS, was correlated with the TAC. Individual antioxidants namely vitamin C, E and glutathione were also estimated and correlated with TAC. Results: TAC was found to be significantly lower in Eales’ disease with active vasculitis (0.28 ± 0.09 mM, P<0.001), Eales’ disease with healed vasculitis (0.67 ± 0.09 mM), uveitis (0.46 ± 0.09 mM, P<0.001) and cataract (0.53 ± 0.1 mM, P=0.001) compared to the healthy controls, with a TAC level of 0.77 ± 0.09 mM. The TAC was found to correlate positively with vitamin E levels (P=0.05), GSH (P=0.02) but not with vitamin C, as seen in ED cases. In ED cases supplemented with vitamin E and C, there was a significant increase in the TAC level (P=0.02). Interpretation & conclusions: The TAC measurement provided a comprehensive assay for establishing a link between the antioxidant capacity and the risk of disease as well as monitoring antioxidant therapy. This method is a good substitute for assay of individual antioxidants as it clearly gives the status of the oxidative stress in the disease process.

Vitamina C / Vitamin C

La vitamina C es una de las principales vitaminas antioxidantes. El hombre, es uno de los poco mamíferos que no puede sintetizarla orgánicamente. La vitamina C desarrolla funciones bioquímicas que incluyen su participación en la síntesis de colágeno y carnitina; funciones fisiológicas que tienen que ver con el fortalecimiento del sistema inmunológico y la regulación de la respuesta frente a reacciones alérgicas. La vitamina C está ampliamente distribuida en la naturaleza, pero su consumo puede ser sobrestimado porque las tablas de composición de alimentos no consideran las pérdidas de la vitamina producidas por la cocción.

Vitamin C and oxidative stress in the seminiferous epithelium

In this article, we focus on the fundamental role of vitamin C transporters for the normal delivery of vitamin C to germ cells in the adluminal compartment of seminiferous tubules. We argue that the redox status within spermatozoa or in semen is partly responsible for the etiology of infertility. In this context, antioxidant defence plays a critical role in male fertility. Vitamin C, a micronutrient required for a wide variety of metabolic functions, has long been associated with male reproduction. Two systems for vitamin C transport have been described in mammals. Facilitative hexose transporters (GLUTs), with 14 known isoforms to date, GLUT1-GLUT14, transport the oxidized form of vitamin C (dehydroascorbic acid) into the cells. Sodium ascorbic acid co-transporters (SVCTs), SVCT1 and SVCT2 transport the reduced form of vitamin C (ascorbic acid). Sertoli cells control germ cell proliferation and differentiation through cell-cell communication and form the blood-testis barrier. Because the blood-testis barrier limits direct access of molecules from the plasma into the adluminal compartment of the seminiferous tubule, one important question is the method by which germ cells obtain vitamin C. Some interesting results have thrown light on this matter. Expression of SVCT2 and some isoforms of GLUT transporters in the testis have previously been described. Our group has demonstrated that Sertoli cells express functionally active vitamin C transporters. Kinetic characteristics were described for both transport systems (SVCT and GLUT systems). Sertoli cells are able to transport both forms of vitamin C. These findings are extremely relevant, because Sertoli cells may control the amount of vitamin C in the adluminal compartment, as well as regulating the availability of this metabolite throughout spermatogenesis.

Therapeutic role of L-arginine on free radical scavenging system in ischemic heart diseases.

Increased production of free radicals under oxidative stress conditions plays a vital role in the impairment of endothelial function and also in the pathogenesis of ischemic heart diseases. Ischemia, followed by reperfusion, leads to the exacerbated formation of oxy- free radicals. These reactive oxygen species through a chain of reactions damage the cardiomyocytes and cause more injury to the myocardium. L-Arginine is reported to act as free radical scavenger, inhibits the activity of pro-oxidant enzymes and thus acts as an antioxidant and these roles of L-arginine are mediated by nitric oxide (NO). In the present study, the effect of oral administration of L-arginine (3 g/day for 7 days) on some antioxidant enzymes, total thiols, lipid peroxidation measured as malondialdehyde (MDA), and plasma ascorbate levels in myocardial ischemic patients was investigated. We observed an increase in the activity of superoxide dismutase (SOD), total thiols (T-SH) and plasma ascorbate levels and a decrease in the activity of xanthine oxidase (XO), MDA levels, carbonyl content and serum cholesterol in the patients on oral administration of L-arginine. The present study demonstrates that L-arginine administration may be beneficial to patients with myocardial ischemic disorders, such as acute myocardial infarction and acute angina.

Analysis of myenteric neurons of the cecum of diabetic rats after supplementation with ascorbic acid / Análisis de neuronas mientéricas del ciego de ratas diabéticas después de suplementación con ácido ascórbico

The objective of this work was to investigate the neuroprotective action of the ascorbic acid over the myenteric neurons in the cecum of Wistar rats, four months after induction of the diabetes mellitus experimental with streptozotocin. Three groups with five rats each were used: C- controls, D- diabetic, DA- diabetic treated with ascorbic acid. For evidentiation of the myenteric neurons was carried out to Giemsa's technique. Were evaluated the areas of cell bodies of 500 neurons in each group studied. The quantitative analysis was carried out in an area of 16.6 mm2 in each cecum studied. In the animals diabetic observed elevation of the glycemia and glycated hemoglobin. The supplementation with ascorbic acid was effective under the myenteric neurons of the cecum of diabetics rays, since was presented the effect neuroprotective and neurotrofic.

El objetivo de este trabajo fue verificar el efecto neuroprotector del ácido ascórbico sobre las neuronas mientéricas en el ciego de Rattus Wistar, cuatro meses después de la inducción de diabetes mellitus experimental con estreptozotocina. Utilizamos tres grupos de animales: C- control, D- diabético, DA- diabético tratado con ácido ascórbico. Para la observación de las neuronas mientéricas fue llevado a cabo la técnica de Giemsa. Fueron evaluadas las áreas del soma de 500 neuronas, en cada grupo estudiado. El análisis cuantitativo fue llevado a cabo, en cada ciego, en un área de 16,6 mm². En los animales diabéticos, se observó la elevación de la glicemia y de la hemoglobina glicosilada. La suplementación con ácido ascórbico fue efectiva en las neuronas mientéricas del ciego de animales diabéticos, ya que se produjeron los efectos neuroprotetor y neurotrófico.

Stress modulating antioxidant effect of Nardostachys jatamansi.

The rhizomes of Nardostachysjatamansi, the plant commonly known as Jatamansi have been described in Ayurveda for their soothing and sedative action on the central nervous system. In the present study, the anti-stress effect of hydroethanolic extract (70%) of N. jatamansi (NJE) was evaluated in reference to its antioxidant property. Wistar rats were divided into four groups: naive, stressed, and T-200 and T-500 stressed with oral pre-treatment of NJE 200 and 500 mg/kg, respectively. Restraint of rats in metallic chambers for 4 h at 4 degreesC was followed by sacrifice and assessment of stress-induced alterations in biochemical parameters, incidence and severity of ulcers. Lipid peroxidation (LPO) and NO levels in stomach and LPO, NO levels and catalase activity in brain, plasma corticosterone level and adrenal ascorbic acid were measured. In vitro antioxidant activity of NJE was studied by measuring the free radical scavenging activity. NJE showed potent antioxidant activity and significantly reversed the stress-induced elevation of LPO and NO levels and decrease in catalase activity in the brain. It inhibited the incidence of gastric ulcerations and reversed the alterations in biochemical parameters/markers of stress-induced gastric ulceration. NJE also significantly altered stress-induced increase in adrenal and spleen weights and decrease in level of ascorbic acid in adrenal gland. Elevation of plasma corticosterone level was negated dose- dependently. The findings suggest that the NJE possesses significant anti-stress activity, which may be due to its antioxidant activity.

The Relationship between Leaf Rolling and Ascorbate-Glutathione Cycle Enzymes in Apoplastic and Symplastic Areas of Ctenanthe setosa Subjected to Drought Stress

The ascorbate-glutathione (ASC-GSH) cycle has an important role in defensive processes against oxidative damage generated by drought stress. In this study, the changes that take place in apoplastic and symplastic ASC-GSH cycle enzymes of the leaf and petiole were investigated under drought stress causing leaf rolling in Ctenanthe setosa (Rose.) Eichler (Marantaceae). Apoplastic and symplastic extractions of leaf and petiole were performed at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others are intermediate forms). Glutathione reductase (GR), a key enzyme in the GSH regeneration cycle, and ascorbate (ASC) were present in apoplastic spaces of the leaf and petiole, whereas dehydroascorbate reductase (DHAR), which uses glutathione as reductant, monodehydroascorbate reductase (MDHAR), which uses NAD(P)H as reductant, and glutathione were absent. GR, DHAR and MDHAR activities increased in the symplastic and apoplastic areas of the leaf. Apoplastic and symplastic ASC and dehydroascorbate (DHA), the oxidized form of ascorbate, rose at all scores except score 4 of symplastic ASC in the leaf. On the other hand, while reduced glutathione (GSH) content was enhanced, oxidized glutathione (GSSG) content decreased in the leaf during rolling. As for the petiole, GR activity increased in the apoplastic area but decreased in the symplastic area. DHAR and MDHAR activities increased throughout all scores, but decreased to the score 1 level at score 4. The ASC content of the apoplast increased during leaf rolling. Conversely, symplastic ASC content increased at score 2, however decreased at the later scores. While the apoplastic DHA content declined, symplastic DHA rose at score 2, but later was down to the level of score 1. While GSH content enhanced during leaf rolling, GSSG content did not change except at score 2. As well, there were good correlations between leaf rolling and ASC-GSH cycle enzyme activities ...