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Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid  

International Nuclear Information System (INIS)

Graphical abstract: Ascorbic acid is used as an inhibitor to retard the oxidation rate of magnesium sulfite. It shows that the oxidation rate would decrease greatly with the rise of initial ascorbic acid concentration, which provides a useful reference for sulfite recovery in magnesia desulfurization. -- Highlights: • We studied the kinetics of magnesium sulfite oxidation inhibited by ascorbic acid. • The oxidation process was simulated by a three-phase model and proved by HPLC–MS. • We calculated the kinetic parameters of intrinsic oxidation of magnesium sulfite. -- Abstract: Magnesia flue gas desulfurization is a promising process for small to medium scale industrial coal-fired boilers in order to reduce sulfur dioxide emissions, in which oxidation control of magnesium sulfite is of great importance for the recycling of products. Effects of four inhibitors were compared by kinetic experiments indicating that ascorbic acid is the best additive, which retards the oxidation process of magnesium sulfite in trace presence. The macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid were studied. Effects of the factors, including ascorbic acid concentration, magnesium sulfite concentration, oxygen partial pressure, pH, and temperature, were investigated in a stirred reactor with bubbling. The results show that the reaction rate is ?0.55 order in ascorbic acid, 0.77 in oxygen partial pressure, and zero in magnesium sulfite concentration, respectively. The apparent activation energy is 88.0 kJ mol?1. Integrated with the kinetic model, it is concluded that the oxidation rate of magnesium sulfite inhibited by ascorbic acid is controlled by the intrinsic chemical reaction. The result provides a useful reference for sulfite recovery in magnesia desulfurization

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Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Ascorbic acid is used as an inhibitor to retard the oxidation rate of magnesium sulfite. It shows that the oxidation rate would decrease greatly with the rise of initial ascorbic acid concentration, which provides a useful reference for sulfite recovery in magnesia desulfurization. -- Highlights: • We studied the kinetics of magnesium sulfite oxidation inhibited by ascorbic acid. • The oxidation process was simulated by a three-phase model and proved by HPLC–MS. • We calculated the kinetic parameters of intrinsic oxidation of magnesium sulfite. -- Abstract: Magnesia flue gas desulfurization is a promising process for small to medium scale industrial coal-fired boilers in order to reduce sulfur dioxide emissions, in which oxidation control of magnesium sulfite is of great importance for the recycling of products. Effects of four inhibitors were compared by kinetic experiments indicating that ascorbic acid is the best additive, which retards the oxidation process of magnesium sulfite in trace presence. The macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid were studied. Effects of the factors, including ascorbic acid concentration, magnesium sulfite concentration, oxygen partial pressure, pH, and temperature, were investigated in a stirred reactor with bubbling. The results show that the reaction rate is ?0.55 order in ascorbic acid, 0.77 in oxygen partial pressure, and zero in magnesium sulfite concentration, respectively. The apparent activation energy is 88.0 kJ mol{sup ?1}. Integrated with the kinetic model, it is concluded that the oxidation rate of magnesium sulfite inhibited by ascorbic acid is controlled by the intrinsic chemical reaction. The result provides a useful reference for sulfite recovery in magnesia desulfurization.

Lidong, Wang, E-mail: wld@tsinghua.edu.cn [School of Environmental Science and Engineering, North China Electric Power University, Baoding 071003 (China); Department of Environmental Science and Engineering, Tsinghua University, Beijing 100054 (China); Yongliang, Ma, E-mail: liang@tsinghua.edu.cn [Department of Environmental Science and Engineering, Tsinghua University, Beijing 100054 (China); Wendi, Zhang; Qiangwei, Li; Yi, Zhao [School of Environmental Science and Engineering, North China Electric Power University, Baoding 071003 (China); Zhanchao, Zhang [Jinan Environmental Monitoring Center, Jinan 250014 (China)

2013-08-15

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Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid.  

Science.gov (United States)

Magnesia flue gas desulfurization is a promising process for small to medium scale industrial coal-fired boilers in order to reduce sulfur dioxide emissions, in which oxidation control of magnesium sulfite is of great importance for the recycling of products. Effects of four inhibitors were compared by kinetic experiments indicating that ascorbic acid is the best additive, which retards the oxidation process of magnesium sulfite in trace presence. The macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid were studied. Effects of the factors, including ascorbic acid concentration, magnesium sulfite concentration, oxygen partial pressure, pH, and temperature, were investigated in a stirred reactor with bubbling. The results show that the reaction rate is -0.55 order in ascorbic acid, 0.77 in oxygen partial pressure, and zero in magnesium sulfite concentration, respectively. The apparent activation energy is 88.0 kJ mol(-1). Integrated with the kinetic model, it is concluded that the oxidation rate of magnesium sulfite inhibited by ascorbic acid is controlled by the intrinsic chemical reaction. The result provides a useful reference for sulfite recovery in magnesia desulfurization. PMID:23692683

Lidong, Wang; Yongliang, Ma; Wendi, Zhang; Qiangwei, Li; Yi, Zhao; Zhanchao, Zhang

2013-08-15

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Ascorbic Acid  

Science.gov (United States)

Ascorbic acid is used to prevent and treat scurvy, a disease caused by a lack of vitamin C ... Ascorbic acid comes in extended-release (long-acting) capsules and tablets, lozenges, syrup, chewable tablets, and liquid drops ...

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Vitamin C (Ascorbic acid)  

Science.gov (United States)

... to Rate. The effectiveness ratings for VITAMIN C (ASCORBIC ACID) are as follows:Treatment and prevention of vitamin ... Vitamin, Ascorbate, Ascorbate de Calcium, Ascorbate de Sodium, Ascorbic acid, Ascorbyl Palmitate, Calcium Ascorbate, Cevitamic Acid, Iso-Ascorbic ...

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A novel biological role of dehydroascorbic acid: Inhibition of Na(+)-dependent transport of ascorbic acid.  

Science.gov (United States)

A U937 cell clone, in which low micromolar concentrations of ascorbic acid (AA) and dehydroascorbic acid (DHA) are taken up at identical rates, was used to investigate possible interactions between transport systems mediating cellular uptake of the two forms of the vitamin. Results obtained with different experimental approaches showed that DHA potently and reversibly inhibits AA uptake through Na(+)-AA cotransporters. Hence, a progressive increase in extracellular DHA concentrations in the presence of a fixed amount of AA caused an initial decrease in the net amount of vitamin C accumulated, and eventually, at higher levels, it caused an accumulation of the vitamin solely based on DHA uptake through hexose transporters. DHA-dependent inhibition of AA uptake was also detected in various other cell types. Taken together, our results provide evidence of a novel biological effect mediated by concentrations of DHA compatible with those produced at inflammatory sites. PMID:24769194

Fiorani, Mara; Azzolini, Catia; Guidarelli, Andrea; Cerioni, Liana; Cantoni, Orazio

2014-06-01

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Ascorbic acid inhibits PMP22 expression by reducing cAMP levels.  

Science.gov (United States)

Charcot-Marie-Tooth [CMT] syndrome is the most common hereditary peripheral neuropathy. CMT1A, which accounts for 50% of all CMT cases, usually results from triploidy of the PMP22 gene. Preclinical trials using an animal model show that disabled mice force-fed with high doses of ascorbic acid partially recover muscular strength after a few months of treatment, and suggest that high doses of ascorbic acid repress PMP22 expression. In this study, we demonstrated that ascorbic acid represses PMP22 gene expression by acting on intracellular cAMP levels and adenylate cyclase activity. This action is dose dependent and specific to ascorbic acid, since repression is not observed after treatment with other antioxidants. The new properties of ascorbic acid are discussed, along with the implications of these findings for CMT disease treatment. PMID:17303424

Kaya, Ferdinand; Belin, Sophie; Bourgeois, Patrice; Micaleff, Joelle; Blin, Olivier; Fontés, Michel

2007-03-01

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Ascorbic acid supplementation enhances recovery from ethanol induced inhibition of Leydig cell steroidogenesis than abstention in male guinea pigs.  

Science.gov (United States)

The impact of ascorbic acid supplementation against ethanol induced Leydig cell toxicity was studied in guinea pigs. Male guinea pigs were exposed to ethanol (4g/kgb.wt.) for 90 days. After 90 days, ethanol administration was completely stopped and animals in the ethanol group were divided into abstention group and ascorbic acid supplemented group (25mg/100gb.wt.) and those in control group were maintained as control and control+ascorbic acid group. Ethanol administration reduced the serum testosterone and LH (luteinising hormone) levels and elevated estradiol levels. Cholesterol levels in Leydig cell were increased whereas the mRNA and protein expressions of StAR (steroidogenic acute regulatory) protein, cytochrome P450scc (cytochrome p450side chain cleavage enzyme), 3?-HSD (3?-hydroxysteroid dehydrogenase), 17?-HSD (17?-hydroxysteroid dehydrogenase) and LH receptor were drastically reduced. Administration of ascorbic acid resulted in alteration of all these parameters indicating enhanced recovery from ethanol induced inhibition of Leydig cell steroidogenesis. Although abstention could also reduce the inhibition of steroidogenesis, this was lesser in comparison with ascorbic acid supplemented group. PMID:24333212

Radhakrishnakartha, Harikrishnan; Appu, Abhilash Puthuvelvippel; Indira, Madambath

2014-01-15

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ASCORBIC ACID MODULATES SPONTANEOUS THYMOCYTE APOPTOSIS  

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Full Text Available The aim of the paper was to analyze the effect of various concentrations of ascorbic acid on spontaneous apoptosis of lymphocytes.About 58% of all thymocytes are subjected to a spontaneous apoptosis, after 24-hour cultivation in the complete medium. The number of apoptotic thymocytes was much lower in the culture with different concentrations of ascorbic acid. The most dramatic effect was detected in the culture with the highest concentration of ascorbic acid (10000 ?g/ml. In this culture, the number of apoptotic thymocytes was about 32%. These results, compared with the results of spontaneous apoptosis, show that the most significant inhibition of apoptosis was detected in the culture with 10000 ?g/ml of ascorbic acid. High concentration of ascorbic acid can inhibit spontaneous apoptosis of thymocytes. Such inhibition of T cell apoptosis, as the effector cells in immune system, can represent one of the major factors by which ascorbic acid influence the immune system.

Goran Rankovi?

2005-12-01

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Ascorbic acid inhibition of Candida albicans Hsp90-mediated morphogenesis occurs via the transcriptional regulator Upc2.  

Science.gov (United States)

Morphogenetic transitions of the opportunistic fungal pathogen Candida albicans are influenced by temperature changes, with induction of filamentation upon a shift from 30 to 37°C. Hsp90 was identified as a major repressor of an elongated cell morphology at low temperatures, as treatment with specific inhibitors of Hsp90 results in elongated growth forms at 30°C. Elongated growth resulting from a compromised Hsp90 is considered neither hyphal nor pseudohyphal growth. It has been reported that ascorbic acid (vitamin C) interferes with the yeast-to-hypha transition in C. albicans. In the present study, we show that ascorbic acid also antagonizes the morphogenetic change caused by hampered Hsp90 function. Further analysis revealed that Upc2, a transcriptional regulator of genes involved in ergosterol biosynthesis, and Erg11, the target of azole antifungals, whose expression is in turn regulated by Upc2, are required for this antagonism. Ergosterol levels correlate with elongated growth and are reduced in cells treated with the Hsp90 inhibitor geldanamycin (GdA) and restored by cotreatment with ascorbic acid. In addition, we show that Upc2 appears to be required for ascorbic acid-mediated inhibition of the antifungal activity of fluconazole. These results identify Upc2 as a major regulator of ascorbic acid-induced effects in C. albicans and suggest an association between ergosterol content and elongated growth upon Hsp90 compromise. PMID:25084864

Van Hauwenhuyse, Frédérique; Fiori, Alessandro; Van Dijck, Patrick

2014-10-01

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Metalloporphyrin synergizes with ascorbic acid to inhibit cancer cell growth through fenton chemistry.  

Science.gov (United States)

Ascorbic acid (AA) has been reported to inhibit tumor cell growth through the generation of extracellular hydrogen peroxide (H(2)O(2)). However, the clinical utility of AA has been limited by relatively low potency and in vivo efficacy. This study reports that the metalloporphyrin, Mn(III) tetrakis(N-methylpyridinium-2-yl)porphyrin(5+) (MnTMPyP), has a potent synergistic cytotoxic effect when combined with AA in a variety of cancer cell lines. In the presence of MnTMPyP, the concentration of AA required to inhibit cancer cell growth was markedly reduced. In vitro (cell-free) experiments demonstrated that AA alone enhanced the Fenton reaction that produces cytotoxic hydroxyl radical (HO(*)); however, this reaction was limited by the low rate by which AA generates H(2)O(2) (Fenton reaction substrate) from O(2). MnTMPyP catalyzed H(2)O(2) generation through the AA-facilitated Mn(II III)TMPyP redox cycle and thereby markedly potentiated the Fenton reaction. Accordingly, MnTMPyP and AA resulted in increased cellular levels of H(2)O(2) and HO(*) in cancer cells, which mediate the synergistic cytotoxicity of this combined treatment. This effect was inhibited by cellular enzymes that metabolize H(2)O(2), such as catalase and glutathione peroxidase, suggesting that selective killing of cancer cells deficient in such enzymes can be achieved in vivo. PMID:20735206

Tian, Junqiang; Peehl, Donna M; Knox, Susan J

2010-08-01

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Ascorbic acid transport into cultured pituitary cells  

International Nuclear Information System (INIS)

An amidating enzyme designated peptidyl-glycine ?-amidating monooxygenase (PAM) has been studied in a variety of tissues and is dependent on molecular oxygen and stimulated by copper and ascorbic acid. To continue investigating the relationship among cellular ascorbic acid concentrations, amidating ability, and PAM activity, the authors studied ascorbic acid transport in three cell preparations that contain PAM and produce amidated peptides: primary cultures of rat anterior and intermediate pituitary and mouse AtT-20 tumor cells. When incubated in 50 ?M [14C]ascorbic acid all three cell preparations concentrated ascorbic acid 20- to 40-fold, producing intracellular ascorbate concentrations of 1 to 2 mM, based on experimentally determined cell volumes. All three cell preparations displayed saturable ascorbic acid uptake with half-maximal initial rates occurring between 9 and 18 ?M ascorbate. Replacing NaCl in the uptake buffer with choline chloride significantly diminished ascorbate uptake in all three preparations. Ascorbic acid efflux from these cells was slow, displaying half-lives of 7 hours. Unlike systems that transport dehydroascorbic acid, the transport system for ascorbic acid in these cells was not inhibited by glucose. Thus, ascorbate is transported into pituitary cells by a sodium-dependent, active transport system

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Ascorbic acid inhibits development of tolerance and dependence to opiates in mice: Possible glutamatergic or dopaminergic modulation  

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Full Text Available In a recent study, it has been demonstrated that ascorbic acid possessed antidopaminergic activity and modulate the glutamatergic neurotransmission in mice. With this background, the present study was undertaken to study the effect of ascorbic acid on the development of tolerance and dependence to opiate and its mechanism of action. Male Swiss mice weighing 20-25 g were used in the present study. Mice were made physically dependent on opioid by the chronic administration of morphine (10 mg/kg, twice a day, for 9 days intraperitoneally. Ascorbic acid, haloperidol (dopamine antagonist or MK 801 (NMDA receptor antagonist was administered daily for 9 d before challenging the animals with morphine. The development of tolerance was assessed by noting the tail-flick latency on day 1, 3, 9 and 10. On the 10 th day after the measurement of tail-flick latency, animals were challenged with naloxone (2 mg/kg., i.p. and incidence of escape jumps were recorded by placing the animals in 45 cm high plexiglass container. Ascorbic acid (400-1600 mg/kg dose dependently inhibited development of tolerance and dependence to morphine as noted from tail-flick latency. When given along with MK 801 (0.01 mg/kg., i.p or haloperidol (0.1 mg/kg i.p., ascorbic acid (800 mg/kg., i.p. potentiated the response of MK 801 or haloperidol. In conclusion, it is hypothesized that inhibition of development of tolerance and dependence to morphine by ascorbic acid appears to have two components, namely dopaminergic and glutamatergic.

Kulkarni S

2008-01-01

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Ascorbic acid inhibits replication and infectivity of avian RNA tumor virus  

Energy Technology Data Exchange (ETDEWEB)

Ascorbic acid, at nontoxic concentrations, causes a substantial reduction in the ability of avian tumor viruses to replicate in both primary avian tendon cells and chicken embryo fibroblasts. The virus-infected cultures appear to be less transformed in the presence of ascorbic acid by the criteria of morphology, reduced glucose uptake, and increased collagen synthesis. The vitamin does not act by altering the susceptibility of the cells to initial infection and transformation, but instead appears to interfere with the spread of infection through a reduction in virus replication and virus infectivity. The effect is reversible and requires the continuous presence of the vitamin in the culture medium.

BISSELL, MINA J; HATIE, CARROLL; FARSON, DEBORAH A.; SCHWARZ, RICHARD I.; SOO, WHAI-JEN

1980-04-01

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Inhibition of radiation induced apoptosis in escherichia coli and bacillus subtilis by ascorbic acid and zinc sulphate  

International Nuclear Information System (INIS)

Programmed cell death or apoptosis a process of physiological cell death, was expressed as DNA fragmentation. The process was carried out in two isolates of bacteria bacillus subtilis and escherichia coli by exposure to dose of gamma-radiation equal to their D10 value. Post irradiation treatment of these bacteria with ascorbic acid at concentrations 400, 500 and 600 mg/ml or zinc sulfate at conentrations 10, 20 and 50 mg/ml at different times showed that these compounds inhibit radiation induced apoptosis in both species. It had been investigated that DNA fragmentation appears to be an essential step in apoptosis after radiation injury and that a strong potentiation of this inhibitory effect was obtained with ascorbic acid and zinc sulfate

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Ascorbic acid inhibits polymorphonuclear leukocytes influx to the place of inflammation--possible protection of lung from phagocyte-mediated injury.  

Science.gov (United States)

Ascorbic acid as a scavenger of oxidants derived from human polymorphonuclear leukocytes (PMNL) may have clinical significance in antioxidant prevention of emphysema. However, there is a risk relevant to its administration because this drug was reported to enhance PMNL chemotactic response and thus could create protease burden in the lower airways. In this study we have investigated the effect of ascorbic acid on the PMNL influx to the place of inflammation developed in the mouse pleural cavity after injection of zymosan-activated serum (ZAS). We also evaluated the influence of ascorbic acid on human PMNL spontaneous migration, chemotaxis to ZAS and n-formyl-methionyl-leucyl-phenylalanine (FMLP) under agarose. The previous ascorbic acid intraperitoneal administration (single dose 10 mg per day for 3 following days) inhibited leukocyte influx. Total number of cells found in the cavity, number of PMNL and lymphocytes was 2.4, 3.5, 1.7-fold lower than in animals without ascorbic acid, respectively. In vitro ascorbic acid (concentrations of 1 to 10 mg/dl) enhanced PMNL spontaneous migration, concentrations 10 mg/dl and higher inhibited PMNL chemotaxis to ZAS and had no influence on migration of the cells toward FMLP. These results suggest that ascorbic acid may be useful for prevention of lung oxidant injury not only as oxidant scavenger but also as an inhibitor of PMNL influx to the pulmonary tissue. PMID:2619505

Nowak, D; Ruta, U; Piasecka, G

1989-01-01

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In silico approach to inhibition of tyrosinase by ascorbic acid using molecular docking simulations.  

Science.gov (United States)

Current evidence suggests that endogenous dopamine may act as a neurotoxin following its oxidation to an oquinone and reaction with cellular thiols, which are neutoxic, which may occur spontaneously or via reaction with tyrosinase or some other enzymes. Tyrosinase (E.C. 1.14.18.1) with two cupper ions coordinated by three histidines is a bifunctional enzyme that catalyses both the hydroxylation of tyrosine to L-DOPA and the consequent oxidation of the resulting catechol-containing species to an o-quinone. Therefore, tyrosinase may play a role in neuromelanin formation in the brain and could be central to dopamine neurotoxicity by contributing to the neurodegeneration associated with Parkinson's disease. In the present study, inhibitory effect of ascorbic acid against tyrosinase has been investigated and it has shown a remarkable inhibitory effect in in vitro assays. Then, the in silico-based experiments established through molecular docking calculations and scoring, docking search algorithm, and data plotting indicated that ascorbic acid is strong inhibitor of tyrosinase by interacting with four amino acid units (histidine 263, serine 282, phenylalanine 264, and valin 283) in the active site of the enzyme. The compound also had two long distant hydrogen bindings with Cu1 and Cu2 with distances of 3.57 and 3.41 A, respectively, through its O5 atom. PMID:24917394

Senol, F Sezer; Khan, M Tareq Hassan; Orhan, Gurdal; Gurkas, Erdem; Orhan, Ilkay Erdogan; Oztekin, Nese Subutay; Ak, Fikri

2014-01-01

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Potential Application of Ascorbic Acid, Citric Acid and Oxalic Acid for Browning Inhibition in Fresh-Cut Fruits and Vegetables  

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Full Text Available The market for fresh-cut fruits and vegetables has grown rapidly in recent decades as a result of their freshness, convenience, and human health benefits. However, fresh fruits and vegetables deteriorate very rapidly after processing, especially cut-surface browning resulting from wound-induced physiological and biochemical changes. The application of antibrowning agents is one of the most effective methods for controlling the enzymatic browning reaction in fresh-cut fruits and vegetables. This article reviews the use of nature identical antibrowning agents, which are generally recognized as safe (GRAS including ascorbic acid, citric acid and oxalic acid for preventing browning in fresh-cut fruits and vegetables. Factors affecting inhibitory efficiency of the antibrowning agents and synergistic effects of the mixtures in various fresh-cut fruits and vegetables are presented.

Weerayuth SUTTIRAK

2010-01-01

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High dose concentration administration of ascorbic acid inhibits tumor growth in BALB/C mice implanted with sarcoma 180 cancer cells via the restriction of angiogenesis  

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Full Text Available Abstract To test the carcinostatic effects of ascorbic acid, we challenged the mice of seven experimental groups with 1.7 × 10-4 mol high dose concentration ascorbic acid after intraperitoneal administrating them with sarcoma S-180 cells. The survival rate was increased by 20% in the group that received high dose concentration ascorbic acid, compared to the control. The highest survival rate was observed in the group in which 1.7 × 10-4 mol ascorbic acid had been continuously injected before and after the induction of cancer cells, rather than just after the induction of cancer cells. The expression of three angiogenesis-related genes was inhibited by 0.3 times in bFGF, 7 times in VEGF and 4 times in MMP2 of the groups with higher survival rates. Biopsy Results, gene expression studies, and wound healing analysis in vivo and in vitro suggested that the carcinostatic effect induced by high dose concentration ascorbic acid occurred through inhibition of angiogenesis.

Lee Hye

2009-08-01

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21 CFR 582.5013 - Ascorbic acid.  

Science.gov (United States)

...5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids listed in this subpart may be free hydrochloride salt, hydrated, or anhydrous form, where applicable. (b) Conditions of use. This substance is generally...

2010-04-01

 
 
 
 
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Apoptosis by 6-O-palmitoyl-L-ascorbic acid coincides with JNK-phosphorylation and inhibition of Mg2+-dependent phosphatase activity.  

Science.gov (United States)

6-O-Palmitoyl ascorbic acid (PAA) has recently been used as a substitute for ascorbic acid because of its greater potency as an antioxidant. In detailed concentration response studies distinct cytotoxic effects of PAA at concentrations exceeding 100 microM were reported. Here we examined and further characterized this cytotoxicity. While ascorbic acid was tolerated well up to millimolar concentrations, PAA revealed an LC50 between 125 and 150 microM in rat GH3 tumor cells. Morphological and biochemical observations suggested the induction of apoptosis at concentrations exceeding 125 microM with a prominent activation of caspase 3 at 250 microM after 4 hr. A subsequent pronounced fragmentation of DNA (DNA-ladder) was detected after 6 hr and was further enhanced after 12 hr. The activation of caspases and the cleavage of its substrate PARP was preceded by a distinct increase in the phosphorylation of stress activated JNK-kinases. This observation suggested that the agent affected signal transduction mechanisms regulating protein phosphorylation at serine/threonine residues in the cell. No effect of PAA on protein phosphatase 2A (PP2A)-like activity was observed while magnesium-dependent protein phosphatase activity, presumably PP2C, was inhibited concentration-dependently up to 75% at the respective concentrations. Thus, the cytotoxic, pro-apoptotic effect of PAA might be related to the inhibition of PP2C and the activation of JNK. PMID:15104245

Kaap, S; Brechlin, P; Quentin, I; Eger, K; Steinfelder, H J

2004-03-01

22

Ascorbic acid specific utilization by some yeasts.  

Science.gov (United States)

One hundred and eighty strains of yeasts belonging to 17 genus and 53 species were screened for their ability to grow on ascorbic acid and iso-ascorbic acid as the sole carbon source. Most of the tested strains (157) were unable to grow on either compound. Strains of seven species of the genus Cryptococcus, of two Candida species, of Filobasidiella neoformans, Trichosporon cutaneum, Lipomyces starkeyi, Hansenula capsulata, and one strain of Aureobasidium pullulans were able to grow on ascorbic as well as on iso-ascorbic acid. Conversely, four strains of Aureobasidium pullulans, Candida blankii, and Cryptococcus dimennae could use only ascorbic acid for growth. PMID:3779527

Costamagna, L; Rosi, I; Garuccio, I; Arrigoni, O

1986-09-01

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Ascorbic Acid and Methylene Blue  

Science.gov (United States)

The WebWare molecules of the month for May are featured in several articles in this issue. "Arsenic: Not So Evil After All?" discusses the pharmaceutical uses of methylene blue and its development as the first synthetic drug used against a specific disease. The JCE Classroom Activity "Out of the Blue" and the article "Greening the Blue Bottle" feature methylene blue and ascorbic acid as two key ingredients in the formulation of the blue bottle. You can also see a colorful example of these two molecules in action on the cover. "Sailing on the 'C': A Vitamin Titration with a Twist" describes an experiment to determine the vitamin C (ascorbic acid) content of citrus fruits and challenges students, as eighteenth-century sea captains, to decide the best fruit to take on a long voyage.

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Characterization of ascorbic acid uptake by isolated rat kidney cells  

International Nuclear Information System (INIS)

Isolated kidney cells accumulated L[1-14C]ascorbic acid in a time-dependent manner and reached a steady state after 15 min at 37 degrees C. Initial velocity for uptake was over 300 pmol/mg protein per min when cells were separated from the bathing solution using a density gradient established during centrifugation. The uptake process was saturable with an apparent concentration at half maximal uptake of 36 mumols/L. Ascorbate uptake was reduced by metabolic inhibitors and was temperature dependent. Although ascorbic acid is an acid anion at pH 7.4, uptake did not appear to be inhibited by other acid anions such as p-aminohippurate and probenecid; however, involvement of the ion gradient established by Na+, H(+)-adenosine triphosphatase could not be confirmed. Replacing the sodium ion with other monovalent ions reduced the accumulation of ascorbate significantly. Isoascorbic and dehydroascorbic acids inhibited ascorbate uptake (34 and 13 mmol/L, respectively), whereas high concentrations of glucose showed some stimulation. These findings indicated that ascorbic acid is reabsorbed by the kidney in a sodium-dependent active transport process that is not common to other acid anions and has some specificity for the ascorbic acid structure

25

Characterization of ascorbic acid uptake by isolated rat kidney cells  

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Isolated kidney cells accumulated L(1-14C)ascorbic acid in a time-dependent manner and reached a steady state after 15 min at 37 degrees C. Initial velocity for uptake was over 300 pmol/mg protein per min when cells were separated from the bathing solution using a density gradient established during centrifugation. The uptake process was saturable with an apparent concentration at half maximal uptake of 36 mumols/L. Ascorbate uptake was reduced by metabolic inhibitors and was temperature dependent. Although ascorbic acid is an acid anion at pH 7.4, uptake did not appear to be inhibited by other acid anions such as p-aminohippurate and probenecid; however, involvement of the ion gradient established by Na+, H(+)-adenosine triphosphatase could not be confirmed. Replacing the sodium ion with other monovalent ions reduced the accumulation of ascorbate significantly. Isoascorbic and dehydroascorbic acids inhibited ascorbate uptake (34 and 13 mmol/L, respectively), whereas high concentrations of glucose showed some stimulation. These findings indicated that ascorbic acid is reabsorbed by the kidney in a sodium-dependent active transport process that is not common to other acid anions and has some specificity for the ascorbic acid structure.

Bowers-Komro, D.M.; McCormick, D.B. (Emory Univ. School of Medicine, Atlanta, GA (USA))

1991-01-01

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Regeneration of ascorbic acid in human placenta  

International Nuclear Information System (INIS)

The free radical scavenging function of ascorbic acid (AA) results in the formation of the oxidized form of the vitamin, dehydro-L-ascorbic acid (DHAA). The enzymatic reduction of DHAA may be an important means of recycling and conserving ascorbic acid in various tissues. The role of the human placenta in the enzymatic reduction of the potentially toxic oxidized form was examined in tissue homogenized in 50 mM MOPs buffer. Assay of DHAA, AA, DKG (diketogulonic acid) were made by HPLC and liquid scintillation counting. Activity of the placental factor in reducing DHAA was dependent on the presence of both NADPH and GSH. Activity was reduced 81% by incubation with 2% trypsin and was unaffected by BSA, glycerol, EtOH, or Na-AZIDE. Inhibition was observed with 10 mM EDTA and 0.2M KCI but not with 1 mM EDTA or 0.1 M KCI or less. Studies are underway to further purify and characterize the enzyme(s) responsible for the observed activity

27

Ascorbic acid improves the antioxidant activity of European grape juices by improving the juices' ability to inhibit lipid peroxidation of human LDL in vitro  

DEFF Research Database (Denmark)

Antioxidant activities of red and white European grape juices towards copper induced lipid oxidation of human low-density lipoproteins (LDL) were examined in vitro. LDL lipid peroxidation was assessed spectrophotometrically by monitoring the development of conjugated lipid hydroperoxides at 234 nm. Red grape juice concentrate inhibited lipid peroxidation of LDL by prolonging the lag phase by 2.7 times relative to a control when evaluated at a total phenolic concentration of 10 muM gallic acid equivalents (GAE). Both red grape juices tested blocked lipid peroxidation of LDL at 20 muM GAE. White grape juice exerted prooxidant activity at 5-20 muM GAE. The antioxidant activity, inhibition of lipid peroxidation of LDL in vitro, was correlated with the juices' levels of total phenols (r > 0.98, P 0.99, P 0.97 P 0.96, P <0.05) when the phenolic composition of each grape juices was analysed by HPLC. 5 M ascorbic acid alone did not exert antioxidant activity towards LDL, but combinations of 5 muM ascorbic acid with 5 muM GAE juice phenols eliminated the prooxidant activity of white grape juice, and significantly improved the antioxidant activities of red grape juices.

Landbo, Anne-Katrine Regel; Meyer, Anne Boye Strunge

2001-01-01

28

Ascorbic acid modulates pathogenecity markers of Candida albicans  

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Full Text Available Candida albicans is an opportunistic commensal of the human gastrointestinal tract and vaginalmucosa, causing opportunistic fungal infections in an immunocompromised patient. In the present study wehave investigated the effect of ascorbic acid on growth and its several pathogenicity markers. Turbidometricmeasurement for growth; proteinase assay, WST-1 cell cytotoxicity assay, colony count method andinverted microscopy were performed to check pathogenecity markers of C. albicans ATCC 10261 strain. 150mg/ml concentration of ascorbic acid arrests cell growth. It was observed that higher ascorbate level of 250mg/ml reduces proteinase secretion (an important mechanism suggestive of virulence in Candida exhibitedby mean precipitation zone value of 2.375 which is remarkably less than that of Control cells (value 4.125.At higher concentration of ascorbic acid increases cell cytotoxcity (79.71 percent inhibition at 150 mg/mland decreases percent viability under oxidative stress (98 percent reduction at 250 mg/ml concentration.Transition studies showed cessation of germ tube induction and hyphae formation at lower concentrations(15 mg onwards of ascorbic acid. Results indicate that higher ascorbic acid level somehow decreasespathogenic attribute of Candida albicans, while yeast to hyphal studies show an exception, were lowerconcentration was effective in inhibiting hyphae formation. Thus ascorbic acid exhibits its pro-oxidant naturein present in-vitro studies.

Ojha R.

2009-06-01

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Degradation of ascorbic acid in ethanolic solutions.  

Science.gov (United States)

Ascorbic acid occurs naturally in many wine-making fruits. The industry also uses ascorbic acid as an antioxidant and color stabilizer in the making of alcoholic beverages including white wine, wine cooler, alcopop, and fruit liqueur. However, the degradation of ascorbic acid itself may cause browning and the deterioration of color quality. This study was aimed to monitor the degradation of ascorbic acid, the formation of degradation products, and the browning in storage of ascorbic acid containing 0-40% (v/v) ethanolic solutions buffered at pH 3.2 as models of alcoholic beverages. The results show that ascorbic acid degradation in the ethanolic solutions during storage follows first-order reaction, that the degradation and browning rates increase with the increase of ethanol concentration, that the activation energy for the degradation of ascorbic acid is in the range 10.35-23.10 (kcal/mol), that 3-hydroxy-2-pyrone is an indicator and a major product of ascorbic acid degradation, and that aerobic degradation pathway dominants over anaerobic pathway in ascorbic acid degradation in ethanolic solutions. PMID:22994409

Hsu, Hsin-Yun; Tsai, Yi-Chin; Fu, Chi-Chang; Wu, James Swi-Bea

2012-10-24

30

21 CFR 862.1095 - Ascorbic acid test system.  

Science.gov (United States)

...false Ascorbic acid test system. 862.1095...CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1095... An ascorbic acid test system is a device...plasma, serum, and urine. Ascorbic acid...

2010-04-01

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21 CFR 862.1095 - Ascorbic acid test system.  

Science.gov (United States)

...device intended to measure the level of ascorbic acid (vitamin C) in plasma, serum, and urine. Ascorbic acid...the diagnosis and treatment of ascorbic acid dietary deficiencies. (b) Classification. Class I (general...

2010-04-01

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Ascorbic acid absorption in Crohn's disease. Studies using L-[carboxyl-14C]ascorbic acid  

International Nuclear Information System (INIS)

Total body pool and intestinal absorption of ascorbic acid were studied in 12 patients undergoing operation for Crohn's disease (six with fistulae and six without) and in six control patients undergoing operation for reasons other than Crohn's disease. L-[carboxyl-14C]Ascorbic acid, 0.19-0.40 megabecquerels (MBq), was given orally. After a period of equilibration, the labeled ascorbic acid was flushed out of the patient's body tissues using large doses of unlabeled ascorbic acid. Intestinal absorption of ascorbic acid, assessed from the total cumulative urinary 14C recovery, was found to be similar in patients with fistulizing Crohn's disease (73.9 +/- 8.45%), those without fistulas (72.8 +/- 11.53%), and in controls (80.3 +/- 8.11%). Total body pools of ascorbic acid, calculated using the plasma 14C decay curves, were similar in patients with Crohn's disease with fistulas (17.1 +/- 5.91 mg/kg), patients without fistulas (9.6 +/- 3.58 mg/kg), and in controls (13.3 +/- 4.28 mg/kg). The results indicate that ascorbic acid absorption is normal in patients with both fistulizing and nonfistulizing Crohn's disease. The results suggest that routine supplements of vitamin C are not necessary unless oral ascorbic acid intake is low

33

Transport of ascorbic acid and dehydroascorbic acid by pancreatic islet cells from neonatal rats  

DEFF Research Database (Denmark)

Several amidated biologically active peptides such as pancreastatin, thyrotropin-releasing hormone, pancreatic polypeptide and amylin are produced in endocrine pancreatic tissue which contains the enzyme necessary for their final processing, i.e. peptidylglycine alpha-amidating mono-oxygenase (EC 1.14.17.3). The enzyme needs ascorbic acid for activity as well as copper and molecular oxygen. The present work shows that pancreatic islet cells prepared from overnight cultures of isolated islets from 5-7-day-old rats accumulate 14C-labelled ascorbic acid by a Na(+)-dependent active transport mechanism which involves a saturable process (estimated Km 17.6 microM). Transport was inhibited by ouabain, phloridzin, cytochalasin B, amiloride and probenecid. Glucose inhibited or stimulated uptake, depending on the length of incubation time of the cells. The uptake of dehydroascorbic acid was linearly dependent on concentration. Dehydroascorbic acid was converted to ascorbic acid by an unknown mechanism after uptake. Theuptake of both ascorbic acid and dehydroascorbic acid was inhibited by tri-iodothyronine, and uptake of ascorbic acid, but not of dehydroascorbic acid, was inhibited by glucocorticoids. Isolated secretory granules contained a fairly low concentration of iron but a high concentration of copper.

Zhou, A; Farver, O

1991-01-01

34

Sensitization of Salmonella typhi towards gamma-radiation by ascorbic acid  

International Nuclear Information System (INIS)

The sensitivity of a S. typhi culture to ?-radiation has been examined. The D10 value, when the culture was irradiated in phosphate buffer, was found to be 70 krad. The addition of ascorbic acid (at a concentration of 0.57 mM) during irradiation, sensitized this organism quite markedly towards ?-radiation. This was evident from the observation that the D10 value was reduced to 20 krad when cells were irradiated in the ascorbic acid. Ascorbic acid was converted to its oxidized form during the radiation process. Irradiation under nitrogen instead of air inhibited the sensitization afforded by ascorbic acid. The population of cells surviving after irradiation in the presence of ascorbic acid showed a higher activity of catalase than its buffer-irradiated counterpart. The implication of the role of hydrogen peroxide (one of the possible intermediates formed during the oxidation of ascorbic acid) in sensitization is discussed. (author)

35

Kinetics of actinide reactions with ascorbic acid  

International Nuclear Information System (INIS)

The studies have been carried out on kinetics of reduction of Npsup((5)) to Npsup((4)) by ascorbic acid in the presence of the catalyst -Fesup((3)) - in the HNO3 solution at constant (?=2) and variable (?=0.5 - 4) ionic strengths. The reaction is limited by a slow stage of interaction between Npsup((5)) and Fesup((2)). The equation for the rate of reaction between Npsup((5)) and Fesup((2)) at ?=2 and 25 deg C is given. The activation energy is equal to 11.1 +- 0.5 kcal/mole. The reduction of Fesup((3)) by ascorbic acid proceds rapidly

36

Electron-impact fragmentation of ascorbic acid  

Science.gov (United States)

The processes of ascorbic acid total and dissociative ionization by 6 to 100 eV electrons in the temperature interval 360-460 K are studied with an MX-7304A monopole mass spectrometer. A scheme of ascorbic acid fragmentation due to electron-impact-induced ionization is suggested, and possible channels of producing the most intense fragment ions in the mass spectrum are indicated. The energy dependences and thresholds of fragment ion formation are determined for the first time in the incident electron energy range 7-30 eV.

Zavilopulo, A. N.; Romanova, L. G.; Shpenik, O. B.; Agafonova, A. S.

2009-04-01

37

21 CFR 182.8013 - Ascorbic acid.  

Science.gov (United States)

21 ? Food and Drugs ? 3 ? 2010-04-01 ? 2009-04-01 ? true ? Ascorbic acid. ? 182.8013 ? Section 182.8013 ? Food and Drugs ? FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ? FOOD FOR HUMAN CONSUMPTION (CONTINUED) ? SUBSTANCES GENERALLY RECOGNIZED AS SAFE ?...

2010-04-01

38

21 CFR 582.5013 - Ascorbic acid.  

Science.gov (United States)

21 ? Food and Drugs ? 6 ? 2010-04-01 ? 2010-04-01 ? false ? Ascorbic acid. ? 582.5013 ? Section 582.5013 ? Food and Drugs ? FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ? ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ? SUBSTANCES GENERALLY RECOGNIZED AS SAFE...

2010-04-01

39

21 CFR 182.3013 - Ascorbic acid.  

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21 ? Food and Drugs ? 3 ? 2010-04-01 ? 2009-04-01 ? true ? Ascorbic acid. ? 182.3013 ? Section 182.3013 ? Food and Drugs ? FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ? FOOD FOR HUMAN CONSUMPTION (CONTINUED) ? SUBSTANCES GENERALLY RECOGNIZED AS SAFE ?...

2010-04-01

40

21 CFR 582.3013 - Ascorbic acid.  

Science.gov (United States)

21 ? Food and Drugs ? 6 ? 2010-04-01 ? 2010-04-01 ? false ? Ascorbic acid. ? 582.3013 ? Section 582.3013 ? Food and Drugs ? FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ? ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ? SUBSTANCES GENERALLY RECOGNIZED AS SAFE...

2010-04-01

 
 
 
 
41

Kinetics of actinide reactions with ascorbic acid  

International Nuclear Information System (INIS)

Studies are performed on kinetics of reduction of Pusup((5)) by ascorbic acid in chlorine oxide solution in the presence of Vsup((5)). The reaction is limited by the stage of interaction between Pusup((5)) and Vsup((4)). The equation for the reaction rate is given at 25.5 deg C and ionic strength, ?=2 and 4, respectively. Reduction of Pusup((4)) to Pusup((3)), and of Vsup((5)) to Vsup((4)) ascorbic acid proceeds rapidly. Activation energies of parallel reaction stages are: E1=11.1 +- 1.5 and 13.7+-0.5 kcal/mole, E2= 14.4 +- 2.3 and 16.0 +- 0.9 kcal/mole at ?=2 and 4, respectively. The reaction mechanism is discussed

42

Titrimetric determination of ascorbic acid using chloranil.  

Science.gov (United States)

Ascorbic acid is oxidized and quantitatively titrated with chloranil (2,3,5,6-tetrachloro-1,4-benzoquinone) in the presence of hexamethylenetetramine in acetone-water; the end point is determined visually by the appearance of a golden yellow color. Colored solutions are assayed by setting the initial absorbance at 451 nm to zero or the minimum, titrating with chloranil solution, and measuring absorbance after each increment of titrant. A plot of the volume of chloranil added against the absorbance gives a straight line with the volume intercept as the end point. Interference by the thiol group of cysteine, glutathione, etc., is avoided by masking with acrylamide; interference by iron(II) is masked with ammonium thiocyanate and sodium potassium tartrate. Hydrogen sulfite and thiourea (which do not interfere) are added as antioxidants during extraction of ascorbic acid from drugs and fruits. PMID:6725194

Verma, K K; Jain, A; Rawat, R

1984-01-01

43

The influence of ascorbic acid on the oxygen consumption and the heat production by the cells of wheat seedling roots with their mitochondrial electron transport chain inhibited at complexes I and III  

International Nuclear Information System (INIS)

The influence of exogenous ascorbic acid (AsA) on oxidative phosphorylation was studied using wheat seedling roots. Treatment of them with AsA stimulated the rates of oxygen consumption and the heat production and caused a decrease of the respiratory coefficient. The increase in respiration was prevented by inhibitors of ascorbate oxidase, diethyldithiocarbamate (DEDTC), and of cytochrome oxidase, cyanide (KCN). Exogenous AsA sharply stimulated the rate of oxygen consumption of roots when complexes I and III of the mitochondrial electron transport chain were inhibited by rotenone and antimycin A, respectively, while the rates of heat production did not change significantly. It is concluded that AsA is a potent energy substrate, which can be used in conditions of failing I and III complexes in the mitochondrial electron transport chain

44

The influence of ascorbic acid on the oxygen consumption and the heat production by the cells of wheat seedling roots with their mitochondrial electron transport chain inhibited at complexes I and III  

Energy Technology Data Exchange (ETDEWEB)

The influence of exogenous ascorbic acid (AsA) on oxidative phosphorylation was studied using wheat seedling roots. Treatment of them with AsA stimulated the rates of oxygen consumption and the heat production and caused a decrease of the respiratory coefficient. The increase in respiration was prevented by inhibitors of ascorbate oxidase, diethyldithiocarbamate (DEDTC), and of cytochrome oxidase, cyanide (KCN). Exogenous AsA sharply stimulated the rate of oxygen consumption of roots when complexes I and III of the mitochondrial electron transport chain were inhibited by rotenone and antimycin A, respectively, while the rates of heat production did not change significantly. It is concluded that AsA is a potent energy substrate, which can be used in conditions of failing I and III complexes in the mitochondrial electron transport chain.

Gordon, L.K. [Kazan Institute of Biochemistry and Biophysics, Kazan Science Center of Russian Academy of Sciences, Kazan (Russian Federation); Rakhmatullina, D.F. [Kazan Institute of Biochemistry and Biophysics, Kazan Science Center of Russian Academy of Sciences, Kazan (Russian Federation); Ogorodnikova, T.I. [Kazan Institute of Biochemistry and Biophysics, Kazan Science Center of Russian Academy of Sciences, Kazan (Russian Federation); Alyabyev, A.J. [Kazan Institute of Biochemistry and Biophysics, Kazan Science Center of Russian Academy of Sciences, Kazan (Russian Federation)]. E-mail: alyabyev@mail.knc.ru; Minibayeva, F.V. [Kazan Institute of Biochemistry and Biophysics, Kazan Science Center of Russian Academy of Sciences, Kazan (Russian Federation); Loseva, N.L. [Kazan Institute of Biochemistry and Biophysics, Kazan Science Center of Russian Academy of Sciences, Kazan (Russian Federation); Mityashina, S.Y. [Kazan Institute of Biochemistry and Biophysics, Kazan Science Center of Russian Academy of Sciences, Kazan (Russian Federation)

2007-06-25

45

Meloidogyne incognita and Tomato Response to Thiamine, Ascorbic Acid, L-arginine, and L-glutamic Acid  

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The influence of solutions of ascorbic acid, thiamine, L-arginine, and L-gtutamic acid on egg hatch, juvenile survival, and development and reproduction of Meloidogyne incognita in susceptible and resistant tomatoes was studied. Maximum inhibition of egg hatch occurred at 2,000, 4,000, and 2,000 ppm for ascorbic acid, L-arginine, and L-glutamic acid, respectively. Larval survival was significantly reduced by concentrations of 2,000 ppm ascorbic acid and 1,000 ppm of L-arginine. Maximum inhibi...

Al-sayed, A. A.; Thomason, I. J.

1988-01-01

46

Allosteric modulation of retinal GABA receptors by ascorbic acid  

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Ionotropic ?-aminobutyric acid receptors (GABAA and GABAC) belong to the cys-loop receptor family of ligand-gated ion channels. GABAC receptors are highly expressed in the retina, mainly localized at the axon terminals of bipolar cells. Ascorbic acid, an endogenous redox agent, modulates the function of diverse proteins, and basal levels of ascorbic acid in the retina are very high. However, the effect of ascorbic acid on retinal GABA receptors has not been studied. Here we show that the fun...

Calero, Cecilia I.; Vickers, Evan; Moraga Cid, Gustavo; Aguayo, Luis G.; Von Gersdorff, Henrique

2011-01-01

47

Supplementation of Ascorbic Acid in Weanling Horses Following Prolonged Transportation  

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Full Text Available Though horses synthesize ascorbic acid in their liver in amounts that meet their needs under normal circumstances, prolonged stress results in low plasma concentrations due to enhanced utilization and renal excretion and can reduce immune function. It was hypothesized that plasma ascorbic acid could be maintained in weanling horses by oral supplementation following prolonged transportation. Weanlings were supplemented with no ascorbic acid (Tx 0: n = 4, 5 grams ascorbic acid twice daily for 5 days (Tx 1: n = 4 or for 10 days (Tx 2: n = 4 following >50 hours of transportation. Supplementation caused slight (P < 0.2 increases in plasma ascorbic acid concentrations. Both supplemented groups had decreased (P < 0.05 plasma concentrations for 1 to 3 weeks following cessation of supplementation, possibly due to increased renal excretion or suppressed hepatic synthesis. Supplementation of ascorbic acid following prolonged stress will increase plasma concentrations, but prolonged supplementation should be avoided.

Michelle Stives

2012-04-01

48

Hepatoprotective Effect of Vitamin C (Ascorbic Acid  

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Full Text Available Human and animal studies have shown that some drugs and chemical agents have potential hepatotoxic effects. The hepatotoxic effect of drugs and some chemical agents is reported to be associated with the generation of reactive oxygen species (ROS. These ROS are reported to be associated with lipid peroxidation in the liver. This mechanism has led to continuous evaluation of the hepatoprotective effect of antioxidants in humans and animals. Among the antioxidants been evaluated is vitamin C which is a water soluble antioxidant. Reports have linked vitamin C with hepatoprotective property in animals and humans. It synergistic hepatoprotective effect with other antioxidants was also reported. Due to these reports a comprehensive literature review on the hepatoprotective property of vitamin C in humans and animals was performed. It was observed that vitamin C exhibited a reputable hepatoprotective effect in humans and animals. Research showed that vitamin C inhibited hepatotoxicity induced by drugs, heavy metals, organophosphate insecticides and some chemical agents. Vitamin C was reported to normalized levels of serum alanine aminotransferase, aspartate aminotransferase, gamma glutamine, alkaline phosphatase, lactate dehydrogenase and malondialdehyde and serum bilirubin in intoxicated animals. It potentiates the activities of free radical scavengers, superoxide dimutase, and catalase glutathione peroxidase thereby preventing microsomal lipid peroxidation, liver fibrosis, liver necrosis and hepatic inflammation. In humans vitamin C was reported to be beneficial in non alcoholic steatohepatitis and in patients with fatty liver disease. Hepatoprotective property of vitamin C is attributed to it antioxidant property. Vitamin C (ascorbic acid which is a major water-soluble antioxidant is believed to decrease lipid peroxidation either directly or indirectly by regenerating vitamin E. Vitamin C is an important free radical scavenger in extracellular fluids, trapping radicals and protecting biomembranes from peroxide damage. Vitamin C effectively scavenges singlet oxygen, superoxide, hydroxyl, water soluble peroxyl radical and hypochlorous acid. It is also reported to be an excellent source of electrons and therefore can donate electrons to free radicals such as hydroxyl and super oxide radicals and quench their activity. Vitamin C is an essential co-factor involved in many biochemical functions and acts as an electron donor or reducing agent. In this review it is observe that vitamin C has hepatoprotective effect which increases when co administered with other agents precisely antioxidants.

Oputiri Deo

2013-01-01

49

Ascorbate inhibition of angiogenesis in aortic rings ex vivo and subcutaneous Matrigel plugs in vivo  

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Full Text Available Abstract Background Angiogenesis is critical to tumor growth and is therefore a potential target for cancer therapy. As many current inhibitors of angiogenesis exhibit host toxicity, natural alternatives are needed. At millimolar concentrations, ascorbate (vitamin C inhibits migration and tubule formation by mature endothelial cells and endothelial progenitors. In the present study, we examined the effects of ascorbate, at levels relevant during intravenous infusion therapy, on angiogenesis using an ex vivo an in vivo assay. Methods Two assays were used to evaluate effect of high-doses ascorbic acid on angiogenesis: ex vivo rat aortic ring explant assay in Matrigel matrices and in vivo Matrigel plug assay. In aortic rings, we quantified microvessel growth, branching and vessel regression under different treatment conditions. In murine angiogenesis assay, male C57 mice 6-8 weeks old were treated by high-dose ascorbic acid and the number of microvessels was analyzed by histological method. To characterize the population of cells that formed capillary network and microvessels, the sections were stained by CD34 and CD31 antibodies. Results Results show that sprouting of endothelial tubules from aortic rings was reduced in a concentration-dependent fashion by ascorbate: while controls roughly tripled sprout densities during the study, ascorbate (1 mg/mL, 5.5 mM actually reduced sprout density. In vivo, the ability of mice to vascularize subcutaneously implanted Matrigel plug was diminished if the mice were treated with 430 mg/kg vitamin C: numbers of vessels, and vessel densities, in plugs from treated mice were roughly 30% less than those in plugs from untreated mice. Conclusions We conclude that the inhibition of angiogenesis by ascorbate suggested in vitro is confirmed in vivo, and that angiogenesis inhibition may be one mechanism by which intravenous ascorbate therapy shows efficacy in animal experiments and clinical case studies.

Casciari Joseph J

2010-01-01

50

Toxic methemoglobinemia treated with ascorbic Acid: case report.  

Science.gov (United States)

Methemoglobinemia is a disorder characterized by the presence of a higher than normal level of methemoglobin. Prilocaine which is one of the oxidizing local anaesthetics is widely used in many local procedures. The first choice of treatment of complications due to the use of these local anaesthetics is methylene blue, while ascorbic acid is the alternative choice. The side effects of metilen blue restrict its usage in some special conditions. Ascorbic acid is a good alternative drug with limited experience in methemoglobinemia. We present a case of a methemoglobinemia treated with ascorbic acid successfully to emphasize the use of ascorbic acid as an alternative method. PMID:24693390

Topal, Hatice; Topal, Yasar

2013-12-01

51

Measuring the Amount of Ascorbic Acid in Cabbage  

Science.gov (United States)

Ascorbic acid may be easily extracted from plant tissue by grinding the tissue in a mortar and estle with 5% metaphosphoric acid. The amount of ascorbic acid present may be determined by titration with a reducible dye, dichlorophenol-indophenol (DCIP).

Carol Reiss (Cornell University;)

1993-01-01

52

Fate of the synergistic antioxidant system ascorbic acid, lecithin, and tocopherol in mayonnaise : Partition of ascorbic acid  

DEFF Research Database (Denmark)

The distribution of ascorbic acid between the lipid and aqueous phase was investigated in mayonnaises enriched with fish oil containing a synergistic antioxidant mixture of ascorbic acid, lecithin and gamma-tocopherol, i.e., the A/L/T system (Loliger and Saucy 1989). The ascorbic acid was found to be located in the aqueous phase indicating that the A/L/T system broke down in mayonnaises. Based on the hypothesis that synergistic antioxidant action between ascorbic acid, lecithin and tocopherol requires that the three components are in close assembly, the results offer an explanation as to why the A/L/T system does not function antioxidatively in mayonnaises.

Meyer, Anne S.; Jacobsen, Charlotte

1996-01-01

53

Ascorbic acid monoglucoside as antioxidant and radioprotector  

International Nuclear Information System (INIS)

Ascorbic acid monoglucoside (AsAG), a glucoside derivative of ascorbic acid, has been examined for its antioxidant and radioprotective abilities. AsAG neutralized 1, 1 diphenyl -2-picryl-hydrazyl (DPPH), a stable free radical in a concentration dependent manner thus indicating its antioxidant ability. AsAG protected mice liver tissues in vitro from peroxidative damage in lipids (measured as TBARS) resulting from 25Gy ? irradiation. It also protected plasmid pBR322 DNA from gamma-radiation induced strand breaks as evidenced from studies on agarose gel electrophoresis of the plasmid DNA after radiation exposure. Oral administration of AsAG to mice prior to whole body gamma radiation exposure (4Gy) resulted in a reduction of radiation induced lipid peroxides in the liver tissue indicating in vivo radiation protection of membranes. Pulse radiolysis studies indicated that AsAG offered radioprotection by scavenging free radicals. The rate constants for the reactions OH and N3 radicals with AsAG were determined to be 6.4 x 109 dm3 mol-1 s-1 and 2.3 x 109 dm3 mol-1 s-1, respectively at pH 7. It was observed that AsAG radicals undergo conjugation as the pH of the solution is raised to 11 in the case of a one-electron oxidation reaction. As the OH· radical adds to the ring, the conjugation effect starts appearing at pH 10. (author)

54

Ascorbic acid monoglucoside as antioxidant and radioprotector.  

Science.gov (United States)

Ascorbic acid monoglucoside (AsAG), a glucoside derivative of ascorbic acid, has been examined for its antioxidant and radioprotective abilities. AsAG neutralized 1, 1 diphenyl -2-picryl-hydrazyl (DPPH), a stable free radical in a concentration dependent manner thus indicating its antioxidant ability. AsAG protected mice liver tissues in vitro from peroxidative damage in lipids (measured as TBARS) resulting from 25Gy gamma irradiation. It also protected plasmid pBR322 DNA from gamma-radiation induced strand breaks as evidenced from studies on agarose gel electrophoresis of the plasmid DNA after radiation exposure. Oral administration of AsAG to mice prior to whole body gamma radiation exposure (4Gy) resulted in a reduction of radiation induced lipid peroxides in the liver tissue indicating in vivo radiation protection of membranes. Pulse radiolysis studies indicated that AsAG offered radioprotection by scavenging free radicals. The rate constants for the reactions OH and N(3) radicals with AsAG were determined to be 6.4 x 10(9) dm(3) mol(-1) s(-1) and 2.3 x 10(9) dm(3) mol(-1) s(-1), respectively at pH 7. It was observed that AsAG radicals undergo conjugation as the pH of the solution is raised to 11 in the case of a one-electron oxidation reaction. As the OH(*) radical adds to the ring, the conjugation effect starts appearing at pH 10. PMID:17726304

Mathew, Dani; Nair, Cherupally Krishnan K; Jacob, Jasmin A; Biswas, Nandita; Mukherjee, Tulsi; Kapoor, Sudhir; Kagiya, Tsutomu V

2007-09-01

55

Development of a new ascorbic acid sensor  

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Full Text Available The SiO2/SnO2/Phosphate composite, SSF, was prepared by the sol-gel process. The redox dye methylene blue was immobilized on the SSF surface. This new material was utilized in the preparation of a modified carbon paste electrode (SSFAM and its electrochemical characteristics were studied by the cyclic voltammetry technique. The SSFAM sensor presented a formal potential of -90 mV vs SCE, excellent stability regarding the number of cycles and regarding the pH of electrolyte support solution ranging from 2.0 to 8.0. The SSFAM sensor was utilized for the determination of ascorbic acid (Vitamin C, utilizing the chronoamperometry technique, and presented a response time of 1.5 s, a linear response range between 2.0 x 10-4 and 3.0 x 10-3 mol L-1, with a detection limit of 7.8 x 10-6 mol L-1, considering a relation signal/noise = 3. The results obtained for real samples by the SSFAM sensor were compared with those from the standard method for determination of ascorbic acid by the 2,6-dichlorophenilindophenol. The comparison of the obtained results by the two methods demonstrated that the SSFAM sensor has great utilization potential.

Antonio Alberto da Silva Alfaya

2006-02-01

56

Kinetics of actinide reaction with ascorbic acid  

International Nuclear Information System (INIS)

The kinetics of the reaction between Np(5) and Pu(3) in nitric acid solution in the presence of ascorbic acid added for the reaction equilibrium shift is studied. The stoichiometry of the general reaction corresponds to the equation: 2NpO2++C6H8O6+6H+=2Np4++C6H6O6+4H2O o. The reaction rate at the ionic force of ?=2 is described with the equation -d[Np(5)]/dt=ksup(+)[Np(5)][Pu(3)][CH)]sup(1.3), where Ksub(2)=5.15+-0.28 molsup(-2.3)xlsup(2.3)xminsup(-1) at 69.5 deg C. The activation energy constitutes E=65+-2 kJ/mol, and the entropy ?S*=-6 entropy units (?=2)

57

Ascorbic acid protects against cadmium-induced endoplasmic reticulum stress and germ cell apoptosis in testes.  

Science.gov (United States)

Cadmium (Cd) is a testicular toxicant which induces endoplasmic reticulum (ER) stress and germ cell apoptosis in testes. This study investigated the effects of ascorbic acid on Cd-evoked ER stress and germ cell apoptosis in testes. Male mice were intraperitoneally injected with CdCl(2) (2.0 mg/kg). As expected, a single dose of Cd induced testicular germ cell apoptosis. Interestingly, Cd-triggered testicular germ cell apoptosis was almost completely inhibited in mice treated with ascorbic acid. Interestingly, ascorbic acid significantly attenuated Cd-induced upregulation of GRP78 in testes. In addition, ascorbic acid significantly attenuated Cd-triggered testicular IRE1? and eIF2? phosphorylation and XBP-1 activation, indicating that this antioxidant counteracts Cd-induced unfolded protein response (UPR) in testes. Finally, ascorbic acid significantly attenuated Cd-evoked upregulation of CHOP and JNK phosphorylation, two components in ER stress-mediated apoptotic pathway. In conclusion, ascorbic acid protects mice from Cd-triggered germ cell apoptosis via inhibiting ER stress and UPR in testes. PMID:22569276

Ji, Yan-Li; Wang, Zhen; Wang, Hua; Zhang, Cheng; Zhang, Ying; Zhao, Mei; Chen, Yuan-Hua; Meng, Xiu-Hong; Xu, De-Xiang

2012-11-01

58

Ascorbic acid enables reversible dopamine receptor 3H-agonist binding  

International Nuclear Information System (INIS)

The effects of ascorbic acid on dopaminergic 3H-agonist receptor binding were studied in membrane homogenates of bovine anterior pituitary and caudate, and rat striatum. In all tissues virtually no stereospecific binding (defined using 1uM (+)butaclamol) of the 3H-agonists N-propylnorapomorphine (NPA), apomorphine, or dopamine could be demonstrated in the absence of ascorbic acid. Although levels of total 3H-agonist binding were three to five times greater in the absence than in the presence of 0.1% ascorbic acid, the increased binding was entirely non-stereospecific. Greater amounts of dopamine-inhibitable 3H-NPA binding could be demonstrated in the absence of 0.1% ascorbic acid, but this measure of ''specific binding'' was demonstrated not to represent dopamine receptor binding since several other catecholamines and catechol were equipotent with dopamine and more potent than the dopamine agonist (+/-)amino-6,7-dihydroxy-1,2,3,4-tetrahydronapthalene (ADTN) in inhibiting this binding. High levels of dopamine-displaceable 3H-agonist binding were detected in fresh and boiled homogenates of cerebellum, an area of brain which receives no dopaminergic innervation, further demonstrating the non-specific nature of 3H-agonist binding in the absence of ascorbic acid. These studies emphasize that under typical assay conditions ascorbic acid is required in order to demonstrate reversible and specific 3Hrate reversible and specific 3H-agonist binding to dopamine receptors

59

Cytogenetic and biochemical effects induced by the treatment with ascorbic acid and citric acid on Picea abies (L. Karst.  

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Full Text Available This paper present the influence of ascorbic acid and citric acid upon the mitotic division, and to the activity of some antioxidant enzymes to Picea abies (L. Karst. The treatment was made through the germination of seeds in ascorbic acid and citric acid. We observed the stimulator or inhibitor effect of ascorbic acid and citric acid to the mitotic index and estimated the aberrations appearance. Comparative the control, the mitotic index increased at 0.1 % concentration ascorbic acid and decreased at 0.25 % and 0.5 % concentration of the same substance. The citric acid induced a decrease in the dynamics of mitotic index comparative the control. Also, we observed an increase of aberrations appearance to the treatment with citric acid. We established the activity of catalase, peroxidase and superoxide dismutase and the influence of ascorbic acid and citric acid to the activity of these antioxidant enzymes. After statistical interpretation emerged that these substances (except 0.25 % ascorbic acid induced an inhibition of catalase activity and a stimulation of peroxidase and superoxide dismutase activity.

Vlad Artenie

2008-05-01

60

Allosteric modulation of retinal GABA receptors by ascorbic acid  

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Summary Ionotropic ?-aminobutyric acid receptors (GABAA and GABAC) belong to the cys-loop receptor family of ligand-gated ion channels. GABAC receptors are highly expressed in the retina, mainly localized at the axon terminals of bipolar cells. Ascorbic acid, an endogenous redox agent, modulates the function of diverse proteins, and basal levels of ascorbic acid in the retina are very high. However, the effect of ascorbic acid on retinal GABA receptors has not been studied. Here we show that the function of GABAC and GABAA receptors is regulated by ascorbic acid. Patch-clamp recordings from bipolar cell terminals in goldfish retinal slices revealed that GABAC receptor-mediated currents activated by tonic background levels of extracellular GABA, and GABAC currents elicited by local GABA puffs, are both significantly enhanced by ascorbic acid. In addition, a significant rundown of GABA-puff evoked currents was observed in the absence of ascorbic acid. GABA-evoked Cl- currents mediated by homomeric ?1 GABAC receptors expressed in Xenopus laevis oocytes were also potentiated by ascorbic acid in a concentration-dependent, stereospecific, reversible, and voltage-independent manner. Studies involving the chemical modification of sulfhydryl groups showed that the two cys-loop cysteines and histidine 141, all located in the ?1 subunit extracellular domain, each play a key role in the modulation of GABAC receptors by ascorbic acid. Additionally, we show that retinal GABAA IPSCs and heterologously expressed GABAA receptor currents are similarly augmented by ascorbic acid. Our results suggest that ascorbic acid may act as an endogenous agent capable of potentiating GABAergic neurotransmission in the CNS. PMID:21715633

Calero, Cecilia I.; Vickers, Evan; Moraga Cid, Gustavo; Aguayo, Luis G.; von Gersdorff, Henrique; Calvo, Daniel J.

2011-01-01

 
 
 
 
61

Ascorbic acid in buffalo ovary in relation to oestrous cycle.  

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Concentration of ascorbic acid was determined in different parts of buffalo ovary at four different stages of oestrous cycle viz. early luteal, mid luteal, late luteal and follicular. The stages were decided from the physical and morphological examinations of corpora lutea. The ovary was dissected in three components viz. corpus luteum, follicular fluid and ovarian stromal tissue for ascorbic acid assay. Corpus luteum showed significant change in concentration of ascorbic acid with the advancement of oestrous cycle, value being highest in late- luteal stage. Follicular fluid and ovarian stromal tissue did not show significant changes in ascorbic acid at any stage of the oestrous cycle. Small follicles, irrespective of the stage of oestrous cycle had, however, significantly higher ascorbic acid content than large follicles. PMID:10549174

Meur, S K; Sanwal, P C; Yadav, M C

1999-04-01

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Effects of cytochalasin B on the uptake of ascorbic acid and glucose by 3T3 fibroblasts: Mechanism of impaired ascorbate transport in diabetes  

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Hyperglycemia and/or hypoinsulinemia have been found to inhibit L-ascorbic acid cellular transport. The resultant decrease in intracellular ascorbic acid may de-inhibit aryl sulfatase B and increase degradation of sulfated glycosaminoglycans (sGAG). This could lead to a degeneration of the extracellular matrix and result in increased intimal permeability, the initiating event in atherosclerosis. The present studies show that the glucose transport inhibitor cytochalasin B blocked the uptake of 3H-2-deoxy-D-glucose by mouse 3T3 fibroblasts. Cytochalasin B also blocked the uptake of 14C-L-ascorbic acid. The results of these studies further support the hypothesis that glucose and ascorbate share a common transport system. This may have important implications concerning the vascular pathology associated with diabetes mellitus

63

Ascorbic acid prevents high glucose-induced apoptosis in human brain pericytes.  

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High glucose concentrations due to diabetes increase apoptosis of vascular pericytes, impairing vascular regulation and weakening vessels, especially in brain and retina. We sought to determine whether vitamin C, or ascorbic acid, could prevent such high glucose-induced increases in pericyte apoptosis. Culture of human microvascular brain pericytes at 25 mM compared to 5mM glucose increased apoptosis measured as the appearance of cleaved caspase 3. Loading the cells with ascorbate during culture decreased apoptosis, both at 5 and 25 mM glucose. High glucose-induced apoptosis was due largely to activation of the receptor for advanced glycation end products (RAGE), since it was prevented by specific RAGE inhibition. Culture of pericytes for 24h with RAGE agonists also increased apoptosis, which was completely prevented by inclusion of 100 ?M ascorbate. Ascorbate also prevented RAGE agonist-induced apoptosis measured as annexin V binding in human retinal pericytes, a cell type with relevance to diabetic retinopathy. RAGE agonists decreased intracellular ascorbate and GSH in brain pericytes. Despite this evidence of increased oxidative stress, ascorbate prevention of RAGE-induced apoptosis was not mimicked by several antioxidants. These results show that ascorbate prevents pericyte apoptosis due RAGE activation. Although RAGE activation decreases intracellular ascorbate and GSH, the prevention of apoptosis by ascorbate may involve effects beyond its function as an antioxidant. PMID:25152398

May, James M; Jayagopal, Ashwath; Qu, Zhi-Chao; Parker, William H

2014-09-12

64

Additional antilipoperoxidant activities of alpha-tocopherol and ascorbic acid on membrane-like systems are potentiated by rutin.  

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The effects of alpha-tocopherol, ascorbic acid and rutin on peroxidative processes were studied in xanthine-xanthine oxidase system, linoleic acid ufasomes and human erythrocyte membranes. In these three systems, tested compounds scavenge superoxide anion radicals or inhibit lipid peroxidation in a concentration-dependent manner, and it was shown that rutin was the most potent radical scavenger, followed by ascorbic acid and alpha-tocopherol. An important antilipoperoxidant activity was observed when these compounds were tested in combination, demonstrating that a dose-dependent interaction occurs. Water-soluble (rutin and ascorbic acid) as well as lipid-soluble (tocopherol) antioxidants are involved in the protection of polyunsaturated fatty acids constituting the ufasome or erythrocyte ghosts. When these compounds are used in combination, an additive effect is observed with alpha-tocopherol and ascorbic acid or rutin, while a supra-additive effect (synergism) is noted with ascorbic acid and rutin. Results obtained with the triple combination alpha-tocopherol-ascorbic acid-rutin show that an increase in superoxide radical scavenging activities or in lipid peroxidation inhibition is possible after the addition of a third antioxidant, as compared with the protective effects produced by the double combination of these compounds. This interaction takes place not only in homogeneous aqueous solutions, but also in ufasome or erythrocyte ghost preparations. It is suggested that ascorbic acid and rutin interacts with tocopherol at the surface of or the interface with the membrane, and that rutin simultaneously interacts with ascorbic acid. PMID:1652140

Nègre-Salvayre, A; Affany, A; Hariton, C; Salvayre, R

1991-01-01

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Ascorbic Acid Efficiently Enhances Neuronal Synthesis of Norepinephrine from Dopamine  

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Ascorbic acid enhances synthesis of norepinephrine from dopamine in adrenal chromaffin cells by serving as a co-factor for chromaffin granule dopamine ?-hydroxylase (D?H). However, there is controversy regarding in situ kinetics of the ascorbate effect in chromaffin cells, as well as whether they apply to neuronal cells. In this study we evaluated the stimulation of norepinephrine synthesis from dopamine in cultured SH-SY5Y neuroblastoma cells. These cells contained neither ascorbate nor norepinephrine in culture, but when provided with dopamine, they generated intracellular norepinephrine at rates that were stimulated several fold by intracellular ascorbate. Ascorbate-induced increases in norepinephrine synthesis in dopamine-treated cells were linear over 60 minutes, despite saturation of intracellular ascorbate. Norepinephrine accumulation after 60 minutes of incubation with 100 ?M dopamine was half-maximal at intracellular ascorbate concentrations of 0.2 – 0.5 mM, which fits well with the literature Km for ascorbate of D?H using dopamine as a substrate. Moreover, these ascorbate concentrations were generated by initial extracellular ascorbate concentrations of less than 25 ?M due to concentrative accumulation by the ascorbate transporter. Treatment with 100 ?M dopamine acutely increased cellular superoxide generation, which was prevented by ascorbate loading, but associated with a decrease in intracellular ascorbate when the latter was present at concentrations under 1 mM. These results show that ascorbate promptly enhances norepinephrine synthesis from dopamine by neuronal cells, that it does so at physiologic intracellular concentrations in accord with the kinetics of D?H, and that it both protects cells from superoxide and by providing electrons to D?H. PMID:23022576

May, James M.; Qu, Zhi-chao; Nazarewicz, Rafal; Dikalov, Sergey

2012-01-01

66

THE EFFECTS OF ASCORBIC ACID ON MEMBRANE TRANSPORT OF GLUCOSE  

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Full Text Available In this study we compared the effects of ascorbic acid on the glucose levels in the plasma.At the beginning of the experiment the level of ascorbic acid and the level of glycemia were determined twelve hours after the last meal. In the following seven days each of the examined women was given, beside the usual nourishment, 1000 mg ascorbic acid (two times a day of 500 mg with breakfast and lunch. The level of ascorbic acid and glycemia was determined on the eight day of the experiment, twenty-four hours after the last taken dosage of ascorbic acid. The achived results of oral glucose ‡ tolerance test (OGTT at the begining and in the end of the test were shown in a table and on a diagram.The intake of ascorbic acid in the dosage of 1000 mg/a day for seven days, intensifies the level of glycemia during OGTT.This hyperglycemia is probaly the consequence of receptor obstruction in cellular membrane by ascorbic acid.

Voja Pavlovic

2004-07-01

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THE EFFECT OF ASCORBIC ACID ON BLAST TRANSFORMATION OF LYMPHOCYTES  

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Full Text Available The impact of ascorbic acid on the intensity of blast transformation of lymphocytes induced by Con-A and LPS mytogens was considered. For the experiments the spleen lymphocytes C3H/HEJ mouse were used. The cells were explored to the impact of different ascorbic acid concentration, and the process of DNA synthesis was measured by frequent marking of 3H-TdR, which were incorporated into a newly sinthetisized DNA. The quantity of the incorporated 3H-TdR was measured by scintillation in the beta counter.The achieved results show that ascorbic acid exemplifies the stimulative influence on blast transformation lymphocyte in dose from 0,075 to 0,175 gamma/2,5x105 cells. With progressive increase of ascorbic acid dosage, the inhibitatory effect of ascorbic acid progressively increases. Ascorbic acid shows a stronger effect on T than on B lymphocytes. These results lead to a conclusion that ascorbic acid has an important effect on the intensity of stimulated lymphocyte activity by mitogen.

Zorica Anti?

2003-07-01

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THE EFFECTS OF ASCORBIC ACID ON MEMBRANE TRANSPORT OF GLUCOSE  

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Full Text Available The level of glycemia and ascorbic acid was tested of oral glucose-tolerance test (OGTT. This test was done on thirty healthy normoglycemic adult women, between 18 and 30 years of age, who showed no clinical signs of endocrine disturbances.At the beginning of the experiment the level of ascorbic acid and the level of glycemia were determined twelve hours after the last meal. In the following seven days eash of the examined women was given, beside the usual nourishment, 1.000 mg ascorbic acid (two times a day of 500 mg with breakfast and lunch. The level of ascorbic acid the last taken dosage of ascorbic acid. The achieved results of OGTT at the beginning and in the end of the test showed the ascorbic acid in the dosage of 1.000 mg/per day for seven days intensified the level glycemia during OGTT.This hyperglycemy is probably the consequence of the receptor obstruction in cellular membrane by ascorbic acid.

Zoran Pavlovic

2004-01-01

69

Phytic acid inhibits lipid peroxidation in vitro.  

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Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100??M and 500??M effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10-20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100??M and 500??M significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100??M and 500??M) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products. PMID:24260736

Zajdel, Alicja; Wilczok, Adam; W?glarz, Ludmi?a; Dzier?ewicz, Zofia

2013-01-01

70

Effect of ascorbic acid on the properties of ammonia caramel colorant additives and acrylamide formation.  

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Ammonia caramels are among the most widely used colorant additives in the food industry. They are commonly prepared through the Maillard reaction and caramelization of mixtures of reducing sugars with ammonia or ammonium salts. Antioxidants are known to inhibit acrylamide formation during the Maillard reaction, and they may affect the properties of the ammonia caramel products. Thus, the objective of this study was to investigate the effect of the antioxidant ascorbic acid on the properties of ammonia caramel. A mixture of glucose and ammonia was allowed to react at 120 °C for 60 min in the presence of ascorbic acid at final concentrations of 0 to 0.08 M. The ammonia caramels obtained from these reactions were all positively charged. As the concentration of ascorbic acid increased, the color intensity of the ammonia caramel showed a decreasing trend, while the intensity of the fluorescence and total amount of pyrazines in the volatiles showed a tendency to increase. The addition of ascorbic acid did not result in obvious changes in the UV-visible spectra of the ammonia caramels and the types of pyrazines in the volatiles were also unchanged. It is noteworthy that the addition of 0.02 to 0.08 M ascorbic acid did reduce the formation of the by-product acrylamide, a harmful substance in food. When the concentration of ascorbic acid added reached 0.04 M, the content of acrylamide in the ammonia caramel was 20.53 ?g/L, which was approximately 44% lower than that without ascorbic acid. As a result, ascorbic acid can be considered to improve the quality and safety of ammonia caramels. PMID:25204396

Chen, Hongxing; Gu, Zhengbiao

2014-09-01

71

Radiation protection by ascorbic acid in sodium alginate solutions  

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Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of 60 Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

72

Polarographic Methods for Determination of Ascorbic Acid in Pharmacetical Preparations  

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Full Text Available Ascorbic acid is determined polarographically present in various types of medicinal samples by internal standard addition method. Potassium hydrogen phthalate buffer (pH 4.0 containing 0.25% oxalic acid and 0.008 % gelatin solution used as supporting electrolytes and maxima suppressor. Presence of colouring matters does not interfere, and sample handling and solution preparation for analysis can be carried out sufficiently fast to prevent appreciable oxidation. Polarographic determination of ascorbic acid can be carried out even in presence of comparable amounts of other ingredients such as Vitamins A, B, C, D, and E. Results of estimation of ascorbic acid present in different multivitamin medicinal samples by internal standard addition method obtained are in good agreement with the quoted values. The method is precise as indicated by low values of standard deviation. Comparative study of ascorbic acid estimation by polarographic internal standard addition method with respect to their manufacturing company was also done

Swaroopa Rani N. Gupta

2014-04-01

73

Radiation protection by ascorbic acid in sodium alginate solutions  

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Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of {sup 60} Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

Aliste, A.J.; Mastro, N.L. Del [Center of Radiation Technology, IPEN/CNEN/SP, University City, 05508-000 Sao Paulo (Brazil)]. E-mail: ajaliste@ipen.br

2004-07-01

74

MYOCARDIAL INFARCTION WITH ITS RELATION TO ASCORBIC ACID  

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Full Text Available The present study includes a total 66 patients with acute myocardial infarction and 66 age group and sex matched healthy controls. 53 (80.3% were males and 13 (19.7% were females. Mean age in patients was 51.76±11.1 and maximum patients were in the age group 40-60 years (75.76%. Mean plasma ascorbic acid in patients (0.37±0.064 mg/dL was lower than controls (0.58±0.16 mg/dL. 50 (75.76% patients had plasma ascorbic acid ?0.4mg/dL as compared to 5 (7.58% controls. Low plasma ascorbic acid (?0.4 mg/dL, hypercholesterolemia (?200 mg/dL, increased triglycerides (?150 mg/dL, decreased HDL (0.40 mg/dL. A total of 8 patients died within one week in hospital, among them 7 had plasma ascorbic acid ?0.04 mg/dL and 1 had plasma ascorbic acid >0.4 mg/dL. At one week 23 patients had plasma ?0.04 mg/dL and 35 had >0.4 mg/dL. A total of 7 patients died in 2nd and 3rd week, among them 5 had plasma ascorbic ?0.40 mg/dL and 2 had plasma ascorbic acid >0.40 mg/dL. At 3 weeks, 8 patients had plasma ascorbic acid ?0.40 mg/dL and 40 had >0.40 mg/dL. A total of 4 patients died and among them 3 had plasma ascorbic ?0.40 mg/dL and 1 had plasma ascorbic acid >0.04 mg/dL. The association was significant (p<0.01 with a relative risk of 15.2 and attributable risk of 93.42% indicating mortality was significantly associated in patients in whom plasma ascorbic acid remained persistently low i.e. ?0.40 mg/dL. The mean plasma ascorbic acid was 0.37±0.06 mg/dL, 0.44±0.08 mg/dL, and 0.50±0.09 mg/dL on admission, at one week and after 3 weeks respectively.

Chaitanyakumar S

2013-02-01

75

Regulation of ascorbic acid synthesis in plants.  

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Ascorbic acid (AsA) is a major antioxidant and plays an important role in plant growth and development. There are two aspects to improve AsA content, including de novo synthesis and recycling from its oxidized form. However, the knowledge of regulatory mechanisms of AsA synthesis pathways and metabolism still remains limited. We have determined that AsA synthesis process was modulated on both transcriptional and post-transcriptional levels in Arabidopsis. GDP-mannose pyrophosphorylase (VTC1) is the initial AsA biosynthetic enzyme in L-galactose pathway, we previously showed that Arabidopsis ERF98 transcriptionally activates gene expression of VTC1 to improve AsA content and respond salt stress; recent discovery of the interaction between photomorphogenic factor COP9 signalosome (CSN) subunit CSN5B and VTC1 indicates that CSN5B promotes VTC1 degradation in the dark, which keeps the change of AsA content from day to night. This mini-review integrates previous reports and recent evidence to better understand the regulatory mechanisms involved in AsA synthesis. PMID:23603957

Wang, Juan; Zhang, Zhijin; Huang, Rongfeng

2013-06-01

76

Effect of irradiation and cooking methods on ascorbic acid levels of four potato cultivars  

International Nuclear Information System (INIS)

The changes in reduced and total ascorbic acid (AA) contents in control and in tubers irradiated to 100 Gy gamma rays for sprout inhibition were studied by HPLC and iodophenol titrimetry methods in four potato cultivars as a function of storage at 15 degC and after cooking by different methods. Both reduced and total ascorbic acid levels decreased in control tubers during the first 3 months in storage recording respectively 22 to 35% and 26 to 45% losses depending on the cultivar. Irradiated tubers recorded additional losses of 5 to 10% and 6.5 to 13%, respectively in reduced and total ascorbic acid levels during the same period but remained in good marketable conditions. Cooking of tubers in boiling water showed maximum loss in vitamin C content, whereas pressure and microwave cooking recorded least losses. The magnitude of losses in reduced and total vitamin C during cooking was comparable in control and in irradiated tubers. (author)

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Acylated ascorbate stimulates collagen synthesis in cultured human foreskin fibroblasts at lower doses than does ascorbic acid.  

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Acylated derivatives of ascorbic acid were found to be active in a number of biochemical and physiological processes. In the present study we investigated the effects of 6-O-palmitoyl ascorbate on collagen synthesis by cultured foreskin human fibroblasts. Our observations indicate a marked stimulatory effect on collagen synthesis by 6-O-palmitoyl ascorbate in the concentration range of 5-20 microM, while the synthesis stimulated by ascorbic acid was maximal at concentrations of 20-100 microM. Cells treated with 10 microM palmitoyl ascorbate for 36 h exhibited a production of collagen threefold greater than those in the presence of 10 microM ascorbic acid, and it was about the same as in cells treated with 100 microM ascorbic acid. By 48 h differences were not significant. Acylated ascorbate impaired vitality of the treated fibroblasts at concentrations exceeding 20 microM in media supplemented with 0.5% FCS. However, most of the cytotoxic effect was neutralized by FCS at a concentration of 10%. The resistance of acylated ascorbate against oxidative degradation as well as the role of free radicals in the modulation of collagen synthesis by ascorbic acid and by its derivatives is discussed. PMID:9862229

Rosenblat, G; Perelman, N; Katzir, E; Gal-Or, S; Jonas, A; Nimni, M E; Sorgente, N; Neeman, I

1998-01-01

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Interaction between ascorbic acid and chlorogenic acid during the formation of nitric oxide in acidified saliva.  

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When saliva and gastric juice are mixed, salivary nitrite is transformed to nitrous acid to produce nitric oxide (NO). The NO formation in acidified saliva was enhanced by ascorbic acid and chlorogenic acid. Thiocyanate ion (SCN(-)) also enhanced the transformation of nitrous acid to NO. During the NO formation in the presence of both ascorbic acid and chlorogenic acid, ascorbic acid was preferentially oxidized. Chlorogenic acid was oxidized after ascorbic acid had been oxidized. Ascorbyl radical was detected during the oxidation of ascorbic acid, and the radical intensity was decreased by chlorogenic acid. The decrease is discussed to be due to the reduction of the oxidation intermediate or product of chlorogenic acid by ascorbyl radical. The result obtained in this study suggests that ascorbic acid was preferentially oxidized and that not only ascorbic acid but also ascorbyl radical could interact with the oxidation intermediate or product of chlorogenic acid when chlorogenic acid was added to the mixture of saliva and gastric juice that contained ascorbic acid. PMID:18922016

Takahama, Umeo; Tanaka, Mariko; Hirota, Sachiko

2008-11-12

79

Anti-angiogenic effect of high doses of ascorbic acid  

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Full Text Available Abstract Pharmaceutical doses of ascorbic acid (AA, vitamin C, or its salts have been reported to exert anticancer activity in vitro and in vivo. One proposed mechanism involves direct cytotoxicity mediated by accumulation of ascorbic acid radicals and hydrogen peroxide in the extracellular environment of tumor cells. However, therapeutic effects have been reported at concentrations insufficient to induce direct tumor cell death. We hypothesized that AA may exert anti-angiogenic effects. To test this, we expanded endothelial progenitor cells (EPCs from peripheral blood and assessed, whether or not high dose AA would inhibit EPC ability to migrate, change energy metabolism, and tube formation ability. We also evaluated the effects of high dose AA on angiogenic activities of HUVECs (human umbilical vein endothelial cells and HUAECs (human umbilical arterial endothelial cells. According to our data, concentrations of AA higher than 100 mg/dl suppressed capillary-like tube formation on Matrigel for all cells tested and the effect was more pronounced for progenitor cells in comparison with mature cells. Co-culture of differentiated endothelial cells with progenitor cells showed that there was incorporation of EPCs in vessels formed by HUVECs and HUAECs. Cell migration was assessed using an in vitro wound healing model. The results of these experiments showed an inverse correlation between AA concentrations relative to both cell migration and gap filling capacity. Suppression of NO (nitric oxide generation appeared to be one of the mechanisms by which AA mediated angiostatic effects. This study supports further investigation into non-cytotoxic antitumor activities of AA.

Ichim Thomas E

2008-09-01

80

Ascorbic Acid Contents in Chili Peppers (Capsicum L.  

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Full Text Available The genus Capsicum commonly known as chili pepper is a major spice crop and is almost cosmopolitan in distribution. The nutritive value of chili pepper is largely determined by ascorbic acid content. The fruits at five ripening stages viz., (M1, M2, M3, M4 and M5 from seventeen cultivars of Capsicum annuum L and one cultivar of Capsicum frutescens L were analyzed for ascorbic acid content. Among eighteen genotypes the C. annuum var. IC: 119262(CA2 showed higher ascorbic acid content (mg/100g FW i.e., 208.0?0.68 (M1, 231.0?0.66 (M2, 280.0?0.31 (M3, 253.0?0.34 (M4 and 173.7?0.27 (M5. The study revealed that the gradual increase in ascorbic acid content from green to red and subsequently declined in the lateral stages (red partially dried and red fully dried fruits. The variability of ascorbic acid content in the genotypes suggests that these selected genotypes may be use full as parents in hybridization programs to produce fruits with good nutritional values.

Owk ANIEL KUMAR

2009-12-01

 
 
 
 
81

Amino acid peroxyl radicals. Formation and reaction with ascorbate  

International Nuclear Information System (INIS)

p> M-1s-1. The peroxyl radicals of all amino acids studied here were reduced by oxidizing ascorbate to the ascorbyl radical. The reaction was followed at 360 nm, where ascorbyl radical has an absorption coefficient of 3300 M-1cm-1, and the derived rate constants were all close to 107 M-1s-1. However, the spontaneous decay of peroxyl radicals is also fast and competes with the reaction with ascorbate. It is to be stressed that reaction of AAOO· and ascorbate gives rise to hydroperoxides (AAOOH) that are also reactive molecules. Our study suggests that reaction with protein radicals may be responsible for the ascorbate loss reported in organisms exposed to oxidative stress.

82

ESR Study on Irradiated Ascorbic Acid Single Crystal  

International Nuclear Information System (INIS)

Food irradiation is a 'cold' process for preserving food and has been established as a safe and effective method of food processing and preservation after more than five decades of research and development. The small temperature increase, absence of residue and effectiveness of treatment of pre-packed food are the main advantages. In food industry, ascorbic acid and its derivatives are frequently used as antioxidant agents. However, irradiation is expected to produces changes in the molecules of food components and of course in the molecules of the agents added as preservation agents such as ascorbic acid. These changes in the molecular structures could cause decreases in the antioxidant actions of these agents. Therefore, the radiation resistance of these agents must be known to determine the amount of radiation dose to be delivered. Electron spin resonance (ESR) is one of the leading methods for identification of intermediates produced after irradiation. ESR spectrum of irradiated solid powder of ascorbic acid is fairly complex and determinations of involved radical species are difficult. In the present work, single crystals of ascorbic acid irradiated by gamma radiation are used to determine molecular structures of radiation induced radicalic species and four radicalic species related in pair with P21 crystal symmetry are found to be responsible from experimental ESR spectrum of gamma irradiated single crystal of ascorbic acidcid

83

The sodium-dependent ascorbic acid transporter family SLC23.  

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Transporters for vitamin C and its oxidized form dehydroascorbic acid (DHA) are crucial to maintain physiological concentrations of this important vitamin that is used in a variety of biochemical processes. The human SLC23 family consists of the Na(+)-dependent vitamin C transporters SVCT1 (encoded by the SLC23A1 gene) and SVCT2 (SLC23A2) as well as an orphan transporter SVCT3 (SLC23A3). Phylogenetically, the SLC23 family belongs to the nucleobase-ascorbate transporter (NAT) family, although no nucleobase transport has yet been demonstrated for the human members of this family. The SVCT1 and SVCT2 transporters are rather specific for ascorbic acid, which is an important antioxidant and plays a crucial role in a many metal-containing enzymes. SVCT1 is expressed predominantly in epithelial tissues such as intestine where it contributes to the supply and maintenance of whole-body ascorbic acid levels. In contrast to various other mammals, humans are not capable of synthesizing ascorbic acid from glucose and therefore the uptake of ascorbic acid from the diet via SVCT1 is essential for maintaining appropriate concentrations of vitamin C in the human body. The expression of SVCT2 is relatively widespread, where it serves to either deliver ascorbic acid to tissues with high demand of the vitamin for enzymatic reactions or to protect metabolically highly active cells or specialized tissues from oxidative stress. The murine Slc23a3 gene encoding the orphan transporter SVCT3 was originally cloned from mouse yolk sac, and subsequent studies showed that it is expressed in the kidney. However, the function of SVCT3 has not been reported and it remains speculative as to whether SVCT3 is a nucleobase transporter. PMID:23506882

Bürzle, Marc; Suzuki, Yoshiro; Ackermann, Daniel; Miyazaki, Hiroki; Maeda, Nobuyo; Clémençon, Benjamin; Burrier, Robert; Hediger, Matthias A

2013-01-01

84

Study of Plasma Ascorbic Acid Levels in Wheezing Children  

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Full Text Available Background: Reactive Oxygen species induced bronchial abnormalities may have important consequences in asthma, the main symptom being wheezing specially in children. Vitamin C is an important antioxidant known to quench the reactive oxygen species. A beneficial effect of fresh fruit consumption on lung function has been observed in several studies. Plasma levels Vitamin C was determined in relation to wheezing symptoms in cross sectional study. Methods: In a cross sectional blood samples of 50 patients attending pediatrics OPD, having wheezing and shortness of breath were analyzed for plasma Ascorbic acid level and compared with healthy controls of same age and sex. Results: The total number of 50 wheezing children were in the age group of 2 to 12 years with similar age matched controls. It was observed that the plasma ascorbic acid concentration in the wheezing children (0.43 – 0.12 mg/dl was significantly decreased as compared to the normal controls ( 0.75 – 0.18 mg/dl P< 0.001. The highly significant low levels of plasma ascorbic acid level in wheezing children was irrespective of sex and severity of symptoms. However the ascorbic acid levels were at the lower side in female and with severe symptoms. Conclusions: Plasma Ascorbic acid levels were significantly, decreased in the process of scavenging the reactive oxygen species. Ascorbic acid directly neutralizes free radical and protects the bronchial tissue from oxidative injury, so it can be concluded that the consumption of fruit rich in vitamin C may reduce wheezing symptoms in children.

Nagdeote AN,

2011-01-01

85

Synergistic Chondroprotective Effect of ?-Tocopherol, Ascorbic Acid, and Selenium as well as Glucosamine and Chondroitin on Oxidant Induced Cell Death and Inhibition of Matrix Metalloproteinase-3—Studies in Cultured Chondrocytes  

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Full Text Available Overproduction of reactive oxygen species and impaired antioxidant defence accompanied by chronic inflammatory processes may impair joint health. Pro-inflammatory cytokines such as interleukin-1? (IL-1? and tumor necrosis factor alpha (TNF-? stimulate the expression of metalloproteinases which degrade the extracellular matrix. Little is known regarding the potential synergistic effects of natural compounds such as ?-tocopherol (?-toc, ascorbic acid (AA and selenium (Se on oxidant induced cell death. Furthermore studies regarding the metalloproteinase-3 inhibitory activity of glucosamine sulfate (GS and chondroitin sulfate (CS are scarce. Therefore we have studied the effect of ?-toc (0.1–2.5 µmol/L, AA (10–50 µmol/L and Se (1–50 nmol/L on t-butyl hydroperoxide (t-BHP, 100–500 µmol/L-induced cell death in SW1353 chondrocytes. Furthermore we have determined the effect of GS and CS alone (100–500 µmol/L each and in combination on MMP3 mRNA levels and MMP3 secretion in IL-1? stimulated chondrocytes. A combination of ?-toc, AA, and Se was more potent in counteracting t-BHP-induced cytotoxicity as compared to the single compounds. Similarly a combination of CS and GS was more effective in inhibiting MMP3 gene expression and secretion than the single components. The inhibition of MMP3 secretion due to GS plus CS was accompanied by a decrease in TNF-? production. Combining natural compounds such as ?-toc, AA, and Se as well as GS and CS seems to be a promising strategy to combat oxidative stress and cytokine induced matrix degradation in chondrocytes.

Anne-Christi Graeser

2009-12-01

86

ANTIOXIDANT AND PRO-OXIDANT EFFECT OF ASCORBIC ACID  

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Full Text Available Free radicals attack proteins, lipids, enzymes and DNA causing pathological changes in organism. There are many mechanisms that organism uses to fight against free radicals. Ascorbic acid is one of the strongest reducers and eliminators of free radicals. It reduces stable oxygenic, azoth and thyol radicals and acts as a primary defense against water radicals in blood. When radicals are dissolved in water suspensions of erythrocytes and low density lipoproteins (LDL, ascorbic acid catches and eliminates free radicals before they arrive to the membrane and LDL molecules. Even though ascorbic acid is not capable of eliminating free radicals out of fluid medium, it acts as synergist to alpha-tocopherol in lipid section, contributes to the lessening of lipid tocoperoxil radicals, and above all, regenerates alpha-tocopherol. Ascorbic acid may act as pro-oxidant under in vitro conditions in the presence of metals; however, this effect is probably not important under in vivo conditions where metal ions, being sequestered, become second reducers.

Goran Rankovic

2005-01-01

87

An Inquiry into the Effect of Heating on Ascorbic Acid  

Science.gov (United States)

Investigations that study the effect of heating on ascorbic acid are commonly performed in schools, but the conclusions obtained are quite variable and controversial. Some results indicate that heating may destroy vitamin C, but others suggest that heating may have no effect. This article reports an attempt to resolve this confusion through a…

Yip, Din Yan

2009-01-01

88

SOURCE, CHEMISTRY, METABOLISM, PHYSIOLOGICAL FUNCTION: ASCORBIC ACID WITH HUMAN HEALTH  

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Full Text Available Ascorbic acid commonly known as Vitamin C and it is water soluble vitamin having Antioxidant characteristics, abound in nature and highly labile.it is very important Vitamin for biosynthesis of collagen, carnitine and neurotransmitters. Some plants and animals synthesised this Vitamin but human, apes and some other are not able to synthesis this Vitamin due to lack of Gulonolactone oxidase enzyme. So, this Vitamin is supplemented by outer source like fruit, vegetable and synthetic pharmaceutical products. The current US recommended dietary allowances (RDA for Ascorbic acid is 100-120 mg/day. Ascorbic acid has many biochemical functions like Antioxidant, Anti-antherogenic, Anti-carcinogenic, immunodulator and its preventing cold. It’s also associated with reduction of incidence of cancer, immunity, blood pressure, drug metabolism and urinary hydroxyproline excretion, tissue regeneration. Mainly it shows effective result in gastric cancer. Ascorbic acid decreases the death risk. Now day, This Vitamin is used in nutraceutical in human biology and health.

Prashansa Sharma

2014-09-01

89

ASCORBIC ACID IS DECREASED IN INDUCED SPUTUM OF MILD ASTHMATICS  

Science.gov (United States)

Asthma is primarily an airways inflammatory disease, and the bronchial airways have been shown to be particularly susceptible to oxidant-induced tissue damage. The antioxidant ascorbic acid (AA) plays an essential role in defending against oxidant attack in the airways. Decreased...

90

21 CFR 172.315 - Nicotinamide-ascorbic acid complex.  

Science.gov (United States)

21 ? Food and Drugs ? 3 ? 2010-04-01 ? 2009-04-01 ? true ? Nicotinamide-ascorbic acid complex. ? 172.315 ? Section 172.315 ? Food and Drugs ? FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ? FOOD FOR HUMAN CONSUMPTION (CONTINUED) ? FOOD ADDITIVES PERMITTED...

2010-04-01

91

Effect of gamma-irradiation on ascorbic acid content of Iraqi dates  

Energy Technology Data Exchange (ETDEWEB)

The effect of gamma-irradiation, in the range of 0-150 Krad, on ascorbic acid content of two varieties of Iraqi dates were investigated. High performance liquid chromatographic technique (HPLC) was employed. Ascorbic acid was not significantly reduced by radiation. The ascorbic acid content for both varieties investigated were found to be higher than that reported in the literature. (author).

Jaddou, H.; Mhaisen, M.T.; Al-Hakim, M. (Iraq Atomic Energy Commission, Baghdad (Iraq). Nuclear Research Centre)

1990-01-01

92

Simultaneous determination of ascorbic acid and isoascorbic acid in food by high pressure liquid chromatography  

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Full Text Available Objective To establish a high pressure liquid chromatography (HPLC method for simultaneous determination of the contents of ascorbic acid and isoascorbic acid in food. Methods Ascorbic acid and isoascorbic acid were separated using a Venusil HILIC column (250 mm×4.6 mm, 5 ?m, 100 ?, taking acetonitrile-0.1% phosphoric acid solution (90?10, v/v as the mobile phase and extractant. Results The average recoveries of ascorbic acid and isoascorbic acid were 96.61% and 96.53%. And their minimum detectable concentration was 0.35 ?g/mL and 0.42 ?g/mL. Conclusion The method is accurate, sensitive and of precision, and can be used for the determination of ascorbic acid and isoascorbic acid in food.

LI Gang

2013-02-01

93

Methane formation by oxidation of ascorbic acid using iron minerals and hydrogen peroxide.  

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The possibility of methane formation in an oxidative environment has been intensely debated, especially since the discovery of methane generation by living plants. However, recent studies with animal tissue suggested that under specific conditions aerobic methane formation is also possible. Here, we investigated the generation of methane in an abiotic model system using bioavailable substances. We show formation of methane in a highly oxidative media, using ascorbic acid, ferrihydrite and hydrogen peroxide as reagents. Methane production was shown to be related to reagent ratio, reaction volume and pH. A 2:1 ratio of hydrogen peroxide to ascorbic acid, catalytic amounts of ferrihydrite and acidic conditions (pH 3) enhanced formation of methane. We further show that gaseous oxygen has a strong influence with higher levels found to inhibit methane formation. This study is a first step towards providing an insight for the reaction mechanism of methane formation that would be applicable to aerobic environments. PMID:20444486

Althoff, Frederik; Jugold, Alke; Keppler, Frank

2010-06-01

94

Adsorption efficiency of poly(malachite green) films towards oxidation of ascorbic acid  

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Thickness of poly(malachite green) films electropolymerized on a glassy carbon electrode surface, the concentration of ascorbic acid, pH value of the solution, and accumulation time were found to affect the adsorption-controlled anodic peak current of ascorbic acid on this polymer film coated electrode. Adsorption efficiency, defined as the ratio of the active sites in polymer films to the amount of adsorbed ascorbic acid molecules, was then proposed and estimated from the comparison of mathematically simulated cyclic voltammograms with experimental ones. The concentration of ascorbic acid is the greatest parameter affected the adsorption efficiency. Poly(malachite green) film electropolymerized on the glassy carbon electrode was found to be not totally active towards oxidation of ascorbic acid when the concentration of ascorbic acid is too high or when the poly(malachite green) film is too thick. The potential shift of ascorbic acid on the modified electrodes was also discussed. (author)

Yang, Nianjun [Diamond Research Center, National Institute of Advanced Industrial Science and Technology, Umezono 1-1-1, Tsukuba 305-8568 (Japan); Wang, Xiaoxia [Graduate School of Engineering, University of Fukui, Bunkyo 3-9-1, Fukui 910-8507 (Japan)

2007-08-01

95

Precipitation behaviors of palladium, rhodium and rhenium with ascorbic acid  

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Recovery of platinum group metals and transition element such as palladium, rhodium, ruthenium and technetium in SNF are becoming important issues around the world, due to their economic values of noble metals and also radio toxicity of technetium. Precipitation is reportedly one of the possible methods to recover platinum group metals. Especially, an ascorbic acid is reviewed as a promising precipitant for palladium recovery. Also some successful results were reported with relation to the selective precipitation of palladium ion in the simulated fission product solution. However, since most of them are qualitative results with limited data and considering that the purity of noble metal is crucial for its value, quantitative data depending on the various experimental variables are also required. In this study, precipitation behaviors for palladium by ascorbic acid were investigated to obtain the qualitative precipitation data depending on the coexisting ions and other operation variables.

Moon, Jei Kwon; Han, Yoon Ju; Lee, Eil Hee; Yang, Han Beom; Lim, Jae Gwan; Jung, Chang Hun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

2005-07-01

96

Rab GTPase Mediated Procollagen Trafficking in Ascorbic Acid Stimulated Osteoblasts  

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Despite advances in investigating functional aspects of osteoblast (OB) differentiation, especially studies on how bone proteins are deposited and mineralized, there has been little research on the intracellular trafficking of bone proteins during OB differentiation. Collagen synthesis and secretion is the major function of OBs and is markedly up-regulated upon ascorbic acid (AA) stimulation, significantly more so than in fibroblast cells. Understanding the mechanism by which collagen is mobi...

Nabavi, Noushin; Pustylnik, Sofia; Harrison, Rene E.

2012-01-01

97

Modelling and analysis of a direct ascorbic acid fuel cell  

Energy Technology Data Exchange (ETDEWEB)

L-Ascorbic acid (AA), also known as vitamin C, is an environmentally-benign and biologically-friendly compound that can be used as an alternative fuel for direct oxidation fuel cells. While direct ascorbic acid fuel cells (DAAFCs) have been studied experimentally, modelling and simulation of these devices have been overlooked. In this work, we develop a mathematical model to describe a DAAFC and validate it with experimental data. The model is formulated by integrating the mass and charge balances, and model parameters are estimated by best-fitting to experimental data of current-voltage curves. By comparing the transient voltage curves predicted by dynamic simulation and experiments, the model is further validated. Various parameters that affect the power generation are studied by simulation. The cathodic reaction is found to be the most significant determinant of power generation, followed by fuel feed concentration and the mass-transfer coefficient of ascorbic acid. These studies also reveal that the power density steadily increases with respect to the fuel feed concentration. The results may guide future development and operation of a more efficient DAAFC. (author)

Zeng, Yingzhi; Wu, Ping [Institute of High Performance Computing, 1 Science Park Road, 01-01, The Capricorn, Singapore 117528 (Singapore); Fujiwara, Naoko; Yamazaki, Shin-ichi; Tanimoto, Kazumi [Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577 (Japan)

2008-10-15

98

Effect of Rosemary, Echinacea, Green Tea Extracts and Ascorbic Acid on Broiler Meat Quality  

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Full Text Available This study evaluated the effect of addition some plant extracts and ascorbic acid in presence of distilled water as the control on the broiler thigh meat color, subsequent lipid oxidation (TBARS and rancidity development during frozen storage of chicken thigh meat. All the extracts were used in the density of 1000 ppm. The results showed that all the antioxidants had significant effect on lipid oxidation as measured by TBARS value during frozen storage at -20°C for 120 days. However, lipid oxidation only occurred to a limited extent and was insufficient to cause rancid flavor development. The results also demonstrated that rosemary and green tea were the most effective antioxidants in stabilization of a* value. Echinacea, green tea and rosemary extracts were effective antioxidants and strongly inhibited oxidation. Present findings show that these plants extracts exhibit greater antioxidant efficiency compared to ascorbic acid.

R. Mirshekar

2009-01-01

99

Uptake of ascorbic acid by freshly isolated cells and secretory granules from the intermediate lobe of ox hypophyses  

DEFF Research Database (Denmark)

Mechanically isolated cells from the intermediate lobe of ox hypophyses contained 40.6 +/- 3.7 nmol mg-1 protein (mean +/- SE, n = 5) of ascorbic acid. They accumulated radioactivity time dependently, on incubation with L-[14C]ascorbic acid in ionic medium dominated by NaCl. No definite saturation of uptake occurred when mechanically isolated cells were incubated with increasing ascorbic acid concentrations up to 0.6 mM. But if such cells were purified on a Percoll gradient, a clear saturation of uptake could be observed. Acetylsalicylic acid reduced the uptake markedly. When cells loaded with L-[14C]ascorbic acid were homogenized and placed on a Percoll gradient, the radioactivity was recovered in several subcellular fractions. Decrease of the Na+ concentration or presence of ouabain in the medium did not cause noticeable changes in uptake by non-purified cells, whereas uptake by purified cells was clearly sodium-dependent. Phloridzin inhibited uptake. Secretory granules from pars intermedia contained 40.0 +/- 3.8 nmol mg-1 protein of ascorbic acid (mean +/- SE, n = 3) and could accumulate L-[14C]ascorbic acid rapidly in a KCl-dominated medium. The uptake was not saturable with ascorbic acid concentration and was not influenced by the presence of I mM ATP + I mM Mg2+ in the medium. The concentration of copper and iron in isolated cells was comparable to that in isolated neurohypophysial nerve terminals, whereas the concentration of zinc was considerably higher in the pars intermedia cells. The concentration of Cu, Zn, Fe and Co in secretory granules from pars intermedia was higher than in secretory granules from neurohypophyses.

Zhou, A; Matsumoto, T

1990-01-01

100

Phase I safety trial of intravenous ascorbic acid in patients with severe sepsis  

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Background Parenterally administered ascorbic acid modulates sepsis-induced inflammation and coagulation in experimental animal models. The objective of this randomized, double-blind, placebo-controlled, phase I trial was to determine the safety of intravenously infused ascorbic acid in patients with severe sepsis. Methods Twenty-four patients with severe sepsis in the medical intensive care unit were randomized 1:1:1 to receive intravenous infusions every six hours for four days of ascorbic acid: Lo-AscA (50 mg/kg/24 h, n?=?8), or Hi-AscA (200 mg/kg/24 h, n?=?8), or Placebo (5% dextrose/water, n?=?8). The primary end points were ascorbic acid safety and tolerability, assessed as treatment-related adverse-event frequency and severity. Patients were monitored for worsened arterial hypotension, tachycardia, hypernatremia, and nausea or vomiting. In addition Sequential Organ Failure Assessment (SOFA) scores and plasma levels of ascorbic acid, C-reactive protein, procalcitonin, and thrombomodulin were monitored. Results Mean plasma ascorbic acid levels at entry for the entire cohort were 17.9?±?2.4 ?M (normal range 50-70 ?M). Ascorbic acid infusion rapidly and significantly increased plasma ascorbic acid levels. No adverse safety events were observed in ascorbic acid-infused patients. Patients receiving ascorbic acid exhibited prompt reductions in SOFA scores while placebo patients exhibited no such reduction. Ascorbic acid significantly reduced the proinflammatory biomarkers C-reactive protein and procalcitonin. Unlike placebo patients, thrombomodulin in ascorbic acid infused patients exhibited no significant rise, suggesting attenuation of vascular endothelial injury. Conclusions Intravenous ascorbic acid infusion was safe and well tolerated in this study and may positively impact the extent of multiple organ failure and biomarkers of inflammation and endothelial injury. Trial registration ClinicalTrials.gov identifier NCT01434121. PMID:24484547

2014-01-01

 
 
 
 
101

Role of Ascorbic Acid on Germination Indexes and Enzyme Activity of Vicia faba Seeds Grown under Salinity Stress  

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Full Text Available The present work aimed to investigate changes in growth and some metabolic activities in NaCl-stressed bean seedlings, and assessing the role of ascorbic acid to alleviate these changes. The germination was carried out to study the response of presoaked faba bean seeds (Vicia faba cv. Misr 2 in freshly prepared ascorbic acid (50 ppm ? 0.3 mM; as recommended dose as described by El-Tayeb, 1995 or distilled water (control for 4 hrs at natural environmental conditions, to salinity stress during germination period. The radicle and plumule lengths were inhibited at high dose of NaCl but, ascorbic acid application to salt-treated seeds seemed to increase radicle and plumule elongation. The radicle and plumule fresh and dry weights were gradually decreased with increasing NaCl concentrations but, a noticeable increase of radicle and plumule fresh and dry weights were reached in seedlings treated with ascorbic acid. The pigment biosynthesis was substantially affected by salt treatment. Addition of ascorbic acid to stressed seedlings more or less furthered the inhibitory effects of salinity. Salinity enhanced the accumulation of reducing sugars in both radicle and plumule of Vicia faba seedlings as compared with control. Ascorbic acid treatment furthered the stimulatory effects of NaCl. Salinity gradually lowered the protein content of plumules. Ascorbic acid treatments raised the accumulation of protein contents in radicle to a great extent compared to those subjected only to NaCl. Plumule alkaloid content was lowered by low and moderate levels of NaCl. Coupling ascorbic acid to salt treated seeds induced a highly significant increase in alkaloid content of plumules compared to its corresponding controls. Sodium chloride treatments to Vicia faba seeds for two days caused a drastic suppression of ?- and ?-amylase activities. Ascorbic acid application to non-salinized seeds seemed without effects whereas, the salt-treated seeds showed more or less furthered the same effect of salinity. From the previous results we can observed that ascorbic acid achieved a better results during germination indexes.

Awatif A. Mohsen

2014-08-01

102

Direct Spectrophotometric Determination of L-ascorbic Acid in the Presence of Potassium Cyanide  

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Full Text Available A simple and highly sensitive direct spectrophotometric method was developed for the determination of L-ascorbic acid. Potassium cyanide (9.21x10-5 mol dm-3 was used to stabilize ascorbic acid in aqueous medium. The molar absorptivity of the proposed method, which does not require an extraction procedure, was 1.38x104 dm3 mol-1 cm-1 at 264 nm. Beer’s law was obeyed in the concentration range of 0.26 – 12.0 ?g ascorbic acid cm-3. Th e relative standard deviation was 1.40 % for the determination of 8.0 ?g ascorbic acid cm-3 (n = 7. The substances commonly found in vitamin C products do not interfere with the determination of ascorbic acid. Other vitamins and organic acids interfere. The proposed procedure was successfully applied to the determination of ascorbic acid in pure form and vitamin C preparations.

Mirsad Salki?

2007-12-01

103

Ascorbic acid-induced browning of (+)-catechin in a model wine system.  

Science.gov (United States)

The ability of ascorbic acid to induce browning of (+)-catechin in a model wine system has been studied. A significant increase in absorbance at 440 nm was observed over 14 days when ascorbic acid was incubated at 45 degrees C with (+)-catechin in a model wine base. The onset of browning was delayed for about 2 days, although the length of the lag period was dependent on the amount of molecular oxygen in the headspace of the reaction system. The lag period was not observed when a preoxidized solution of ascorbic acid was used, suggesting that a product of ascorbic acid oxidation is responsible for the onset of browning. Hydrogen peroxide, when added directly to (+)-catechin in the model system, was not capable of producing the same degree of browning as that generated by ascorbic acid. Liquid chromotography evidence is presented to show that different reaction products are produced by ascorbic acid and hydrogen peroxide. PMID:11262052

Bradshaw, M P; Prenzler, P D; Scollary, G R

2001-02-01

104

Ascorbic acid loss in vegetables: adequacy of a hospital cook-chill system.  

Science.gov (United States)

This research evaluates the ascorbic acid loss of vegetables prepared in a hospital cook-chill plated system. The ascorbic acid loss of three vegetable samples (carrots, peas and potatoes) were measured at various points in the cook-chill system and analysed using the DCPIP method. Substantial losses for all vegetables were identified at the cooking and regeneration stages. The ascorbic acid levels of the selected vegetables when raw ranged from 6 to 10 mg/100 g sample. At the end of the food service cycle the ascorbic acid content of the vegetables was reduced to 1.7-5.8 mg/100 g sample. The largest percentage loss of ascorbic acid, i.e. 76%, was found in mashed potatoes. Peas incurred the least percentage loss, i.e. 42%. This progressive deterioration during the cook-chill plated catering system causes an insubstantial presence of ascorbic acid in the food served to hospitalised patients. PMID:11400468

McErlain, L; Marson, H; Ainsworth, P; Burnett, S A

2001-05-01

105

Anti-transforming nature of ascorbic acid and its derivatives examined by two-stage cell transformation using BALB/c 3T3 cells.  

Science.gov (United States)

The anti-transforming effects of sodium ascorbate and its stable derivatives were examined in the two-stage transformation assay. When BALB/c 3T3 cells were treated with 0.2 microg/ml 20-methylcholanthrene as an initiator, and 100 ng/ml 12-O-tetradecanoylphorbol-13-acetate as a promoter, the addition at the promotion stage of L-ascorbic acid-2-phosphate ester magnesium (APM) was most marked in the inhibition of transformation. The inhibitory effects of sodium ascorbate and ascorbic acid-2-glucoside (AG) were comparable, but weaker than those of APM; L (+)-ascorbic acid-2-sulfate ester disodium 2H(2)O showed little effect. When phorbol 12, 13-didecanoate or tumor necrosis factor alpha (TNF-alpha) were used as promoters, APM also effectively suppressed transformation. PMID:11098084

Tsuchiya, T; Kato-Masatsuji, E; Tsuzuki, T; Umeda, M

2000-11-10

106

Infrared spectra of ascorbic acid and its complexes with zinc(2) and vanadium(4)  

International Nuclear Information System (INIS)

The infrared spectra are studied of ascorbic acid and its complexes with zink(2) and vanadium(4) in the solid state and in aqueous solutions over a wide range of pH. The bands of the spectra of ascorbic acid (H2Asc), its dissociation products (HAsc- and Asc2-), and also complexes of ascorbic acid with zink(2) and vanadium(4) are correlated

107

Elevated oxidative stress and sensorimotor deficits but normal cognition in mice that cannot synthesize ascorbic acid  

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Oxidative stress is implicated in the cognitive deterioration associated with normal aging as well as neurodegenerative disorders such as Alzheimer’s and Parkinson's diseases. We investigated the effect of ascorbic acid (vitamin C) on oxidative stress, cognition and motor abilities in mice null for gulono-?-lactone oxidase (Gulo). Gulo?/? mice are unable to synthesize ascorbic acid and depend on dietary ascorbic acid for survival. Gulo?/? mice were given supplements that provided t...

Harrison, Fiona E.; Yu, S. Sarah; Den Bossche, Kristen L.; Li, Liying; May, James M.; Mcdonald, Michael P.

2008-01-01

108

Effect of ascorbic acid on food preference and consumption in captive capybaras (Hydrochoerus hydrochaeris)  

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The aim of this work was to study the short and long term influences of ascorbic acid on Hydrochoerus hydrochaeris, if supplemented in their food. No differences regarding food intake were observed in the absence of vitamin C. On a daily basis, animals accustomed to food containing ascorbic acid prefered to continue eating the same food. Food preference in capybaras did not seem to depend on ascorbic acid availability; however, when accustomed to vitamin C, capybaras might recognize and selec...

Martín Roberto Alvarez; Fernando Osvaldo Kravetz

2009-01-01

109

Quercetin antagonism of GABAA?? receptors is prevented by ascorbic acid through a redox-independent mechanism.  

Science.gov (United States)

Quercetin is a natural flavonoid widely distributed in plants that acts as a neuroprotective agent and modulates the activity of different synaptic receptors and ion channels, including the ionotropic GABA receptors. GABA(A??) receptors were shown to be antagonized by quercetin, but the mechanisms underlying these antagonistic actions are still unknown. We have analyzed here if the antagonistic action produced by quercetin on GABA(A??) receptors was related to its redox activity or due to alternative mechanism/s. Homomeric GABA(A??) receptors were expressed in frog oocytes and GABA-evoked responses electrophysiologically recorded. Quercetin effects on GABA(A??) receptors were examined in the absence or presence of ascorbic acid. Chemical protection of cysteines by selective sulfhydryl reagents and site directed mutagenesis experiments were also used to determine ?? subunit residues involved in quercetin actions. Quercetin antagonized GABA(A??) receptor responses in a dose-dependent, fast and reversible manner. Quercetin inhibition was prevented in the presence of ascorbic acid, but not by thiol reagents that modify the extracellular Cys-loop of these receptors. H141, an aminoacidic residue located near to the ?? subunit GABA binding site, was involved in the allosteric modulation of GABA(A??) receptors by several agents including ascorbic acid. Quercetin similarly antagonized GABA-evoked responses mediated by mutant (H141D)GABA(A??) and wild-type receptors, but prevention exerted by ascorbic acid on quercetin effects was impaired in mutant receptors. Taken together the present results suggest that quercetin antagonistic actions on GABA(A??) receptors are mediated through a redox-independent allosteric mechanism. PMID:23916728

Calero, Cecilia I; Beltrán González, Andrea N; Gasulla, Javier; Alvarez, Silvia; Evelson, Pablo; Calvo, Daniel J

2013-08-15

110

Neutron scattering and HPLC study on L-ascorbic acid and its degradation  

Energy Technology Data Exchange (ETDEWEB)

The present paper shows a systematic dynamic and kinetic study on L-ascorbic acid and its degradation at high temperature. The neutron scattering study allows, through the behavior of quasi-elastic neutron scattering (QENS) spectra, to characterize the diffusive dynamics of L-ascorbic acid in water mixtures. Ascorbic acid undergoes degradation process at high temperature, but the presence of trehalose in solution markedly avoids ascorbic acid loss enhancing its t{sub 1/2} (half life time), as determined by high performance liquid chromatography (HPLC)

Bellocco, E. [Department of Organic and Biological Chemistry, University of Messina, Messina (Italy)], E-mail: bellocco@isengard.unime.it; Barreca, D.; Lagana, G.; Leuzzi, U. [Department of Organic and Biological Chemistry, University of Messina, Messina (Italy); Migliardo, F.; Torre, R. La; Galli, G. [Department of Physics, University of Messina, Messina (Italy); Galtieri, A. [Department of Organic and Biological Chemistry, University of Messina, Messina (Italy); Minutoli, L.; Squadrito, F. [Department of Clinical and Experimental Medicine and Pharmacology, University of Messina, Messina (Italy)

2008-04-18

111

Effect of Dietary Ascorbic Acid on Performance and Immune Response of Heat Stressed Broiler Chicks  

Directory of Open Access Journals (Sweden)

Full Text Available A total of 112, day-old broiler chicks were reared under summer temperature of the Sudan (35-45°C to study the effect of supplementation of ascorbic acid on the feed intake, Feed Conversion Ratio (FCR, weight gain, immune status and ratio of weight of bursa, thymus and spleen to body weight. Four level of ascorbic acid 0 (control, 150 (low level, 350 (moderate level and 550 (high level mg/kg were used from day 14-42 day. Birds fed low and moderate levels of ascorbic acid (150, 350 mg/kg show high feed intake compared to those fed high level (550 mg/kg, which resulted in improvement in body weight and feed conversion ratio of the moderate and low levels. Dressing percentage was not affected by different level of ascorbic acid. Total white blood cells were reduced as the level of ascorbic acid was increased. Lymphocytes increased in birds fed moderate or high levels of ascorbic acid. Heterophils were decreased in the group fed the moderate level and high levels of ascorbic acid. Monocytes decreased in the groups fed the high level, However, basophils and esinophils were not affected by the different levels of ascorbic acid. The mean weight of lymphoid organs or the ratio of lymphoid organs to body weight was not affected by the different treatments. Antibody titer against Newcastle virus was increased in birds fed diets supplemented with different levels of ascorbic acid.

Hind A.A. Elagib

2012-01-01

112

Water-dispersible ascorbic-acid-coated magnetite nanoparticles for contrast enhancement in MRI  

Science.gov (United States)

Superparamagnetic iron oxide nanoparticles of size ~5 nm surface functionalized with ascorbic acid (vitamin C) form a stable dispersion in water with a hydrodynamic size of ~30 nm. The anti-oxidant property of ascorbic acid is retained after capping, as evidenced from the capability of converting methylene blue to its reduced leuco form. NMR relaxivity studies show that the ascorbic-acid-coated superparamagnetic iron oxide aqueous nanofluid is suitable as a contrast enhancement agent for MRI applications, coupled with the excellent biocompatibility and medicinal values of ascorbic acid.

Sreeja, V.; Jayaprabha, K. N.; Joy, P. A.

2014-07-01

113

Regulation of L-ascorbic acid content in strawberry fruits  

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Plants have several L-ascorbic acid (AsA) biosynthetic pathways, but the contribution of each one to the synthesis of AsA varyies between different species, organs, and developmental stages. Strawberry (Fragaria×ananassa) fruits are rich in AsA. The pathway that uses D-galacturonate as the initial substrate is functional in ripe fruits, but the contribution of other pathways to AsA biosynthesis has not been studied. The transcription of genes encoding biosynthetic enzymes such as D-galacturo...

Cruz-rus, Eduardo; Amaya, Iraida; Sa?nchez-sevilla, Jose? F.; Botella, Miguel A.; Valpuesta, Victoriano

2011-01-01

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Carbonate interlayered hydrotalcites-enhanced peroxynitrous acid chemiluminescence for high selectivity sensing of ascorbic acid.  

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In this study, Mg-Al-carbonate layered double hydroxides (denoted as Mg-Al-CO(3) LDHs) were found to catalyze the chemiluminescence (CL) emission from peroxynitrous acid (ONOOH). The enhanced CL signals resulted from the concentration of peroxynitrite (ONOO(-)) onto the LDHs surface by electrostatic attraction, meaning that ONOO(-) can interact with the intercalated carbonate easily and effectively. Moreover, ascorbic acid can react with ONOO(-), or its decomposition products (e.g., ?OH and ?NO(2)), resulting in a decrease in the CL intensity from the Mg-Al-CO(3) LDHs-catalyzed ONOOH reaction. Based on these findings, a sensitive, selective and rapid CL method was developed for the determination of ascorbic acid using Mg-Al-CO(3) LDHs-catalyzed ONOOH as a novel CL system. The CL intensity was proportional to the concentration of ascorbic acid in the range from 5.0 to 5000 nM. The detection limit (S/N = 3) was 0.5 nM and the relative standard deviation (RSD) for nine repeated measurements of 0.1 ?M ascorbic acid was 2.6%. This method has been successfully applied to determine ascorbic acid in commercial liquid fruit juices with recoveries of 97-107%. This work is not only of importance for a better understanding of the unique properties of LDHs-catalyzed CL but also of great potential for extensive applications in many fields, such as luminescence devices, bioanalysis, and labeling probes. PMID:22382556

Wang, Zhihua; Teng, Xu; Lu, Chao

2012-04-21

115

Peroxydisulfate Oxidation of L-Ascorbic Acid for Its Direct Spectrophotometric Determination in Dietary Supplements  

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A selective and accurate direct spectrophotometric method was developed for the determination of L-as cor bic acid in dietary supplements. Background correction was based on the oxidation of L-ascorbic acid by potassi um peroxydisulfate in an acidic medium. The molar absorptivity of the proposed method was 1.41 · 104 l/(mol · cm) at 265 nm. The method response was linear up to an L-ascorbic acid concentration of 12.00 ?g/ml. The detection limit was 0.11 ?g/ml, and the relative standard deviation was 0.9 % (n = 7) for 8.00 ?g/ml L-ascorbic acid. Other compounds commonly found in the dietary supplements did not interfere with the detection of L-ascorbic acid. The proposed procedure was successfully applied to the determination of L-ascorbic acid in these supplements, and the results obtained agreed with those obtained by iodine titration.

Salki?, M.; Selimovi?, A.; Pašali?, H.; Keran, H.

2014-03-01

116

Synergic interaction between ascorbic acid and antibiotics against Pseudomonas aeruginosa  

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Full Text Available Studies were carried out on in vitro combination of ascorbic acid (AA with six antibiotics against 12 multi-resistant Pseudomonas aeruginosa isolates. Synergic activity was detected with AA chloramphenicol, kanamycin, streptomycin and tetracycline. Indifference was observed to any antibiotics and antagonism only for chloramphenicol. Results indicated that multiresistant P. aeruginosa was affected by combination of AA and antibiotics. Future research on ascorbic acid-antimicrobial interactions may find new methods to control strains of multiresistant P. aeruginosa.Investigou-se in vitro o efeito da combinação do ácido ascórbico (AA com seis antibióticos frente a 12 isolados multirresistentes de Pseudomonas aeruginosa. As concentrações inibitórias mínimas (CIM foram determinadas pelo método de diluição em caldo. Foi estudado o efeito do AA nas CIM pelo cálculo das concentrações inibitórias fracionais (CIF. Para quase todas as combinações AA-antibiótico foi detectado efeito sinérgico, exceto para ampicilina e tobramicina. Indiferença foi observada na interação com todos os antibióticos, porém antagonismo foi somente observado para cloranfenicol. Os resultados deste estudo indicam que o sinergismo contra P. aeruginosa resistentes pode ocorrer entre AA e cloranfenicol, canamicina, estreptomicina e tetraciclina, ainda que as linhagens sejam resistentes aos antibióticos individualmente. Além disso, estes resultados encorajam futuros trabalhos in vivo a respeito da interação AA-antimicrobianos na incessante busca de novas alternativas para o controle de linhagens multirresistentes de P.aeruginosa.

Luciana Cursino

2005-05-01

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Importance of ascorbic acid in the absorption of iron from infant foods  

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The absorption of fortification iron from an infant milk formula and from 3 infant cereals was studied in 121 multiparous women. The mean absorption was less than 3.2% when no added ascorbic acid was present. The nature of the iron compound added to infant cereals did not seem to influence the amount absorbed. Absorption was significantly improved when ascorbic acid was added, the mean increase being threefold with an iron:ascorbic ratio of 1:1.5 molar and more than sixfold with a ratio of 1:3 molar (about 10 mg ascorbic acid per mg iron). (author)

118

Improvement of bioavailability for iron from vegetarian meals by ascorbic acid  

International Nuclear Information System (INIS)

There are two kinds of iron in the diet with respect to the mechanism of absorption, heme-iron which is present as haemoglobin or myoglobin in meat and blood products, and, non-heme iron which is the main source of dietary iron. The bioavailability of the non-heme food iron is much lower than heme-iron. Vegetarian diets contain only non-heme iron. Iron intake from vegetarian meals are generally satisfied with the requirements, however, the bioavailabilities for non-heme iron is determined not only by iron content byt also the balance between different dietary factors enhancing and inhibiting iron absorption. The main enhancing factor in vegetarian meals is ascorbic acid in fruits and vegetables, inhibitors are phytate in cereals and grains, and tannins in some spices and vegetables. It has been reported that iron deficiency is one of the common micronutrient problems associated with unplanned vegetarian diets. In the present study the absorption of non-heme iron was measured from 2 vegetarian meals containing considerable amounts of phytate and tannin. The extrinsic tay method (59Fe/ 55Fe) was used to labelled the non-heme iron. The mean percentage absorption of non-heme iron from both meals was slightly different due to differences in their dietary contents. Their initial percentages iron absorption were apparent low (3.5% and 4.1%), however, the absorption progressively increased with increase in the level of ascorbic acid, 2-3 times with 100 mg and 4-5 times with 200 mg of ascorbic acid. The average amount of iron absorbed per 2000 kcal increased from 0.37 mg to 0.86 mg and 1.45 mg with the addition of 100 mg and 200 mg ascorbic acid respectively (p < 0.001). Considering the limited caloric intakes and the iron content in the meals, the amount of iron absorbed from vegetarian meals without ascorbic acid was not able to meet certain requirements for children, adolescents and menstruating women. The minimal requirement for dietary iron needed to be absorbed is 0.49 mg for 50% of 1-2 year children and more than 1 mg for girls and menstruating women. The vegetarian meals as compared with ordinary mixed meals can provided most of the nutrients in the amounts close to or above the recommended intaked according to the Recommended Daily Allowances (RDA). However, the amounts of iron absorbed from these meals are quite precarious and fail to meet the requirements for the important target groups. It is suggested that, vegetarian diets can assure nutrient adequacy and promote health when they are planned and chosen in the line with scientific nutrition principles

119

Effects of Household Storage on Ascorbic Acid Content of Some Selected Nigerian Vegetables  

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Full Text Available Effects of household preservation were assessed in five vegetables commonly consumed in major tribes of Nigeria; Hibiscus esculentus, Corchorus olitorus, Lycopersicum esculentum, Talinum triangulare and Amaranthus caudatus. The selected vegetables were purchased from local markets without knowing their maturity age and time of harvest. The wholesomeness of the vegetables was based on physical examination of their texture and colour. The vegetables were divided into two portions. In the first portion, moisture and ascorbic acid were estimated. This served as the control. The second portion was sundried and their moisture and ascorbic acid compositions determined as well. Both moisture and ascorbic acid content of the vegetables were determined using standard methods. Sun-drying decreased ascorbic acid values between 68.1 and 86.7%. Moisture losses due to sun-drying ranged between 80.1 and 96.6%. The highest moisture and ascorbic acid losses were those of Talinum triangulare while Lycopersicum esculentum and Hibiscus esculentus had the least losses of moisture and ascorbic acid, respectively. Sundrying adversely affected ascorbic acid in these vegetables. Nutrition education is therefore necessary to minimize loss of ascorbic acid in vegetables due to household storage methods.

I.C. Obizoba

2013-01-01

120

Enhanced inhibition of DNA synthesis and release of membrane phospholipids in tumour cells treated with a combination of acylated ascorbate and hyperthermia.  

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Combined antitumour effects of mono- or diacyl ascorbates and heat treatment were studied in comparison with the parent compound, L-ascorbic acid (AsA). At 37 degrees C, 75 microM 6-O-palmitoyl (6P) and 6-O-stearoyl (6S) ascorbates appreciably inhibited DNA synthesis in Ehrlich ascites tumour cells. Hyperthermia at 42 degrees C for 1 h increased the inhibition. In contrast, AsA or 2,6-O-dipalmitoyl ascorbate (DP), even at concentrations as high as 100 microM, caused no inhibition at 37 degrees C or 42 degrees C. The results suggest that the inhibitory action is not caused by the fatty acid moiety itself; it is more likely to be caused by the balance in the hydrophobicity and hydrophilicity of the monoacylated AsA, a property not found in diacylated or intact AsA. Inhibition of DNA synthesis caused by exposure to 6P during hyperthermia of tumour cells was greater than before or after hyperthermia. 6P or 6S, but not AsA or DP, released phospholipids such as phosphatidylcholine and phosphatidylethanolamine from cells labelled with [14C]oleic acid, as shown by radiocurves taken from thin-layer chromatograms. Damage of the cell membrane seemed to be involved in the inhibition of DNA synthesis caused by monoacylated AsA, which is surface-active. PMID:2051079

Kageyama, K; Onoyama, Y; Kimura, M; Yamazaki, H; Miwa, N

1991-01-01

 
 
 
 
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Antioxidant activity of the aqueous extracts of spicy food additives--evaluation and comparison with ascorbic acid in in-vitro systems.  

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The antioxidant activity of the aqueous extracts of five umbelliferous fruits--caraway (Carum carvi), coriander (Coriandrum sativum), cumin (Cuminum cyminum), dill (Anethum graveolens) and fennel (Foeniculum vulgare)--were investigated in comparison with the known antioxidant ascorbic acid in in vitro studies. The amount of aqueous extract of these five umbelliferous fruits and ascorbic acid needed for 50% scavenging of superoxide radicals was found to be 105 microg (caraway), 370 microg (coriander), 220 microg (cumin), 190 microg (dill), 205 microg (fennel) and 260 microg (ascorbic acid). The amount needed for 50% inhibition of lipid peroxide was 2100 microg (caraway), 4500 microg (coriander), 4300 microg (cumin), 3100 microg (dill), 4600 microg (fennel) and 5000 microg (ascorbic acid). The quantity needed for 50% inhibition of hydroxyl radicals was 1150 microg (caraway), 1250 microg (coriander), 470 microg (cumin), 575 microg (dill), 700 microg (fennel) and 4500 microg (ascorbic acid). The daily use of the above fruits in various forms is very common in India and the present study revealed strong antioxidant activity of their extracts that was superior to known antioxidant ascorbic acid and indicate their intake may be beneficial as food additives. PMID:15364640

Satyanarayana, S; Sushruta, K; Sarma, G S; Srinivas, N; Subba Raju, G V

2004-01-01

122

The in vitro influence of ascorbic acid on human plasma and the effects of gamma irradiation  

International Nuclear Information System (INIS)

A chemiluminescent technique based on luminol-H2O2 reaction was used to establish the differences in antioxidant capacity of fresh human plasma treated with different concentrations of ascorbic acid. Human plasma revealed marked differences in its antioxidant capacity after an in vitro gamma irradiation if ascorbic acid was present. This suggests an additional exogenous protection offered by ascorbic acid in human fluids and its capacity in depleting the levels of free radicals produced in organism as a result of exogenous oxidants from the inflammations, exposed to environmental pollution or following the radioactive fallout. A logarithmic expression of the relative variation of the chemiluminescent emission as a function of ascorbic acid concentration was found. The calculated coefficient could be a measure of the antioxidant capacity of the studied molecule. As human plasma contains many antioxidant compounds such as urate, ascorbic acid, ?-carotene and others, this coefficient might be a sum of the individual coefficients for each type of molecules. (authors)

123

Chemistry of ascorbic acid and sulfur dioxide as an antioxidant system relevant to white wine.  

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The impact of the combined ascorbic acid and sulfur dioxide antioxidants on white wine oxidation processes was investigated using a range of analytical techniques, including flow injection analysis for free and total sulfur dioxide and two chromatographic methods for ascorbic acid, its oxidative degradation products and phenolic compounds. The combination of different analytical techniques provided a fast and simultaneous means for the monitoring of oxidation processes in a model wine system. In addition, the initial mole ratio of sulfur dioxide to ascorbic acid was varied and the model wine complexity was increased by the inclusion of metal ions (copper(II) and iron(II)). Sulfur dioxide was found not to be a significant binder of ascorbic acid oxidative degradation products and could not prevent the formation of certain phenolic pigment precursors. The results provide a detailed insight into the ascorbic acid/sulfur dioxide antioxidant system in wine conditions. PMID:22688051

Barril, Célia; Clark, Andrew C; Scollary, Geoffrey R

2012-06-30

124

Flow injection spectrophotometric determination of ascorbic acid using iron(III)-bathophenanthroliine disulfonic acid disodium salt  

International Nuclear Information System (INIS)

A single step straightforward, indirect flow injection spectrophotometric determination of ascorbic acid is proposed. The solution of iron (III) and bathophenanthroline disulfonic acid salt in 1 0/sup -4/M HCl media is used as an oxidative reagent. Reagent is reduced to tris-bathophenanthroline disulfonic acid-iron (II) chelate, by the ascorbic acid at room temperature. Spectrophotometric monitoring of absorbance signal of tris chelate at 535 nm is directly related to the concentration of ascorbic acid. The effect of various parameters e.g. pH, flow rate, sample volume, reaction coil length, etc. on the analytical signal were examined and optimized. Under optimized parameters such as sample volume (100mL), flow rate- (2.2 ml/min), reagent concentration (2 x 10/sup -4/ M ammonium iron(III) sulfate + 2 x 10/sup-4/ M bathophenonthroline disulfonic disodium salt.), pH (4.0), reaction coil length (50 cm) and wave length (535 nm), ascorbic acid can be determined in the range of 1-10 /ml (R=0.9924) with sample throughput of 80 samples per hour. Single channel flow injection analysis (FIA) manifold raises the sample throughput as compared to other existing procedures. The validity of the proposed method is tested by analyzing citrus fruits using present and the standard addition method. Results of the two methods are in good agreement.(author)

125

An efficient synthesis of tetramic acid derivatives with extended conjugation from L-Ascorbic Acid  

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Full Text Available Abstract Background Tetramic acids with polyenyl substituents are an important class of compounds in medicinal chemistry. Both solid and solution phase syntheses of such molecules have been reported recently. Thiolactomycin, a clinical candidate for treatment of tuberculosis has led to further explorations in this class. We have recently developed an efficient synthesis of tetramic acids derivatives from L- ascorbic acid. In continuation of this work, we have synthesised dienyl tetramic acid derivatives. Results 5,6-O-Isopropylidene-ascorbic acid on reaction with DBU led to the formation of tetronolactonyl allyl alcohol, which on oxidation with pyridinium chlorochromate gave the respective tetranolactonyl allylic aldehydes. Wittig olefination followed by reaction of the resulting tetranolactonyl dienyl esters with different amines resulted in the respective 5-hydroxy lactams. Subsequent dehydration of the hydroxy lactams with p-toluene sulphonic acid afforded the dienyl tetramic acid derivatives. All reactions were performed at ambient temperature and the yields are good. Conclusion An efficient and practical method for the synthesis of dienyl tetramic acid derivatives from inexpensive and easily accessible ascorbic acid has been developed. The compounds bear structural similarities to the tetramic acid based polyenic antibiotics and thus this method offers a new and short route for the synthesis of tetramic acid derivatives of biological significance.

Bisht Surendra S

2006-12-01

126

Study of Polymorph Prediction For L-Ascorbic Acid  

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Full Text Available Abstract: Possible polymorphs of L-ascorbic acid were investigated, considering eight space groups and assuming one molecule in the asymmetric unit. The grid-search method was compared with a Monte Carlo approach as performed in the Biosym / MSI polymorph Predictor. A number of possible crystal structures were found, including the experimental structure. Energy minimizations were performed with a united-atom force field. In all cases, the experimental structure had a low lattice energy. The number of hypothetical crystal structures was reduced considerably by removing space-group symmetry constraints, or by a primitive molecular dynamic shake-up. Nevertheless, sufficient structures of equal or lower energy compared with the experimental structure remained to suggest that other factors need to be considered for polymorph predictions of materials.

Dilhan M. Kalyon

2005-12-01

127

Amperometric biosensor for ascorbic acid / Biossensor amperométrico para ácido ascórbico  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Desenvolveu-se um biossensor para ácido L-ascórbico empregando ascorbato oxidase. A enzima foi extraída do mesocarpo de pepino com solução tampão fosfato 0,05 mol L-1, pH 5,8 contendo NaCl 0,5 mol L-1. Após diálise versus solução tampão fosfato 0,05 mol L-1, pH 5,8 a enzima foi imobilizada em rede d [...] e nylon através de ligação covalente com glutaraldeído. A membrana foi acoplada em eletrodo de O2 e a reação monitorada pelo consumo de oxigênio a -600 mV em análise em fluxo (solução tampão fosfato 0,05 mol L-1, pH 5,8 como carregador e vazão 0,5 mL min-1). A curva analítica apresentou-se linear entre 1,2x10-4 a 1,0x10-3 mol L-1. O tempo de vida do biossensor foi de 500 análises. Amostras de medicamentos foram analisadas com a metodologia proposta e os resultados comparados com os obtidos com HPLC. Abstract in english A L-ascorbic acid biosensor based on ascorbate oxidase has been developed. The enzyme was extracted from the mesocarp of cucumber (Cucumis sativus) by using 0.05 mol L-1 phosphate buffer, pH 5.8 containing 0.5 mol L-1 NaCl. After the dialysis versus phosphate buffer 0.05 mol L-1 pH 5.8, the enzyme w [...] as immobilized onto nylon net through glutaraldehyde covalent bond. The membrane was coupled to an O2 electrode and the yielding reaction monitored by oxygen depletion at -600 mV using flow injection analysis optimized to 0.1 mol L-1 phosphate buffer pH 5.8, as the carrier solution and flow-rate of 0.5 mL min-1. The ascorbic acid calibration curve was linear from 1.2x10-4 to 1.0x10-3 mol L-1. The evaluation of biosensor lifetime leads to 500 injections. Commercial pharmaceutical samples were analyzed with the proposed method and the results were compared with those obtained by high-performance liquid chromatography (HPLC).

I. N., Tomita; A., Manzoli; F. L., Fertonani; H., Yamanaka.

128

Effect of Dietary Ascorbic Acid on Performance of Broiler Chickens Exposed to Different Lighting Regime  

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Full Text Available A 2 x 2 factorial experiment was conducted to determine the performance of 400 Anak broiler chicks exposed to two lighting regimes viz. 12 h light:12 h darkness and 24 h light:0 h darkness and fed diets containing two levels of ascorbic acid (0 and 250 mg AA/kg of feed. Each treatment was replicated four times with 25 birds per replicate. Results showed that at the starter phase of growth, chicks on continuous lighting regime recorded significantly (p0.05 effect on weight gain but addition of ascorbic acid in the diet significantly (p0.05 between continuous and limited lighting on feed: gain ratio. However, chicks with ascorbic in their diet recorded significantly (p<0.05 better feed: gain ratio than those without ascorbic acid. Inclusion of ascorbic acid in the diet significantly (p<0.05 reduced feed cost per kilogram weight gain. Ascorbic acid inclusion significantly (p<0.05 increased femur weight but not femur ash and tibia length. Continuous lighting and inclusion of ascorbic acid from diets increased incidence of leg abnormality significantly. Inclusion of ascorbic acid significantly (p<0.05 reduced the severity of leg abnormality. In conclusion continuous lighting and ascorbic acid in the diet may improve weight gain, feed: gain ratio, reduced feed cost per kilogram weight gain and reduction in the severity of leg abnormality. It may be recommended that under continuous lighting, inclusion of ascorbic acid in the diet may be recommended for balanced growth of the chicks.

A.I. Okwori

2010-01-01

129

Comparative analysis of ascorbic acid in human milk and infant formula using varied milk delivery systems  

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Full Text Available Abstract Background The expression of human milk for later use is on the rise. Bottle systems are used to deliver the expressed milk. Research has shown that storage of both human milk and artificial baby milk, or infant formula, leads to a loss of ascorbic acid (commonly called Vitamin C. As milk is removed from the bottle during feeding and replaced by ambient air, it is unknown if loss of ascorbic acid occurs during the course of a feeding. The purpose of this study is to investigate the effect of the milk delivery system on levels of ascorbic acid in human milk and infant formula. The objectives are to 1 determine changes in ascorbic acid concentration during a 20 minute "feed," 2 determine if there is a difference in ascorbic acid concentration between delivery systems, and 3 evaluate if any differences are of clinical importance. Methods Commonly available bottles were used for comparison of bottle delivery systems. Mature human milk was standardized to 42 mg/L of ascorbic acid. Infant formula with iron and infant formula with docosahexanoic acid were used for the formula samples. Each sample was analyzed for ascorbic acid concentration at baseline (0, 5, 10, 15, and 20 minutes. Each collection of samples was completed in triplicate. Samples were analyzed for ascorbic acid using normal-phase high performance liquid chromatography. Results Ascorbic acid concentration declined in all bottle systems during testing, Differences between the bottle systems were noted. Ascorbic acid concentrations declined to less than 40% of recommended daily intake for infants in 4 of the bottles systems at the 20 minute sampling. Conclusion The bottle systems used in this study had measurable decreases in the mean concentration of ascorbic acid. More research is needed to determine if the observed decreases are related to lower plasma ascorbic acid concentration in infants exclusively bottle fed. The decrease of ascorbic acid concentration observed in both human milk and infant formula using varied milk delivery systems may be of clinical importance. For infants who rely solely on bottle feeds there may be increased risk of deficiency. Bottle shape, size, and venting should be considered.

Dickton Darby

2008-08-01

130

Ascorbic acid insufficiency induces the severe defect on bone formation via the down-regulation of osteocalcin production  

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The L-gulono-?-lactone oxidase gene (Gulo) encodes an essential enzyme in the synthesis of ascorbic acid from glucose. On the basis of previous findings of bone abnormalities in Gulo-/- mice under conditions of ascorbic acid insufficiency, we investigated the effect of ascorbic acid insufficiency on factors related to bone metabolism in Gulo-/- mice. Four groups of mice were raised for 4 weeks under differing conditions of ascorbic acid insufficiency, namely, wild type; ascorbic acid-sufficient Gulo-/- mice, 3-week ascorbic acid-insufficient Gulo-/- mice, and 4-week ascorbic acid-insufficient Gulo-/- mice. Four weeks of ascorbic acid insufficiency resulted in significant weight loss in Gulo-/- mice. Interestingly, average plasma osteocalcin levels were significantly decreased in Gulo-/- mice after 3 weeks of ascorbic acid insufficiency. In addition, the tibia weight in ascorbic acid-sufficient Gulo-/- mice was significantly higher than that in the other three groups. Moreover, significant decreases in trabecular bone volume near to the growth plate, as well as in trabecular bone attachment to the growth plate, were evident in 3- or 4-week ascorbic acid-insufficient Gulo-/-. In summary, ascorbic acid insufficiency in Gulo-/- mice results in severe defects in normal bone formation, which are closely related to a decrease in plasma osteocalcin levels. PMID:24386598

Kim, Won; Bae, Seyeon; Kim, Hyemin; Kim, Yejin; Choi, Jiwon; Lim, Sun Young; Lee, Hei Jin; Lee, Jihyuk; Choi, Jiyea; Jang, Mirim; Lee, Kyoung Eun; Chung, Sun G.; Hwang, Young-il

2013-01-01

131

Determination of total L-Ascorbic Acid by high performance liquid chromatography in human plasma  

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Full Text Available The total vitamin C content in human plasma is widely accepted as an indicator of the tissue status of vitamin C. A liquid chromatography method with ultraviolet detector (264 nm for measuring ascorbic acid in human plasma was developed. A C18 reversed-phase column and cetrimide as an ion-pairing agent was employed. Ascorbic acid (AA was measured after reducing L-dehydroascorbic acid to L-ascorbic acid with dithiothreitol. The stability of the ascorbic acid in plasma, metaphosphoric acid and trichloroacetic acid was also evaluated. The analytical parameters, including linearity (1-60 µg/ml, accuracy (98.98%, repeatability (2.8% and reproducibility (7.2%, showed that the method is reliable for measuring the total vitamin C content in plasma.

Oveisi MR

2001-07-01

132

Ascorbate enhances u.v.-mutagenesis in E. coli but inhibits it in Chinese hamster cells  

International Nuclear Information System (INIS)

Ascorbic acid (vitamin C) causes an increase in the mutation frequency of u.v.-irradiated Escherichia coli WP2. The enhancement occurs at all u.v. fluences, and is dependent upon the ascorbate concentration in the medium. A maximum effect (approx. 8- to 13-fold) is seen at 100-150 ?g/ml, although some enhancement can be seen even at 10 ?g/ml. The comutagenic effect of ascorbate with u.v. in E. coli is dependent upon peptone, a constituent of nutrient broth. The enhancement of u.v.-mutagenesis by ascorbate is absent in strains WP2sub(s) (uvrA) amd WP6 (polA), suggesting that ascorbate affects the repair of pyrimidine dimers. The opposite results are observed for u.v.-mutagenesis in Chinese hamster V79 cells. The presence of ascorbate (50 ?g/ml) during u.v. irradiation does not enhance the u.v. effect, but rather decreases it approx. 30%. These results are discussed with regard to differences in the mechanism of u.v.-mutagenesis and DNA repair in bacterial and mammalian cells. (author)

133

Ascorbate enhances u.v.-mutagenesis in E. coli but inhibits it in Chinese hamster cells  

International Nuclear Information System (INIS)

Ascorbic acid (vitamin C) causes an increase in the mutation frequency of u.v.-irradiated Escherichia coli WP2. The enhancement occurs at all u.v. fluences, and is dependent upon the ascorbate concentration in the medium. A maximum effect (approximately 8- to 13-fold) is seen at 100-150 micrograms/ml, although some enhancement can be seen even at 10 micrograms/ml. The comutagenic effect of ascorbate with u.v. in E. coli is dependent upon peptone, a constituent of nutrient broth. The enhancement of u.v.-mutagenesis by ascorbate is absent in strains WP2s (uvrA) and WP6 (polA), suggesting that ascorbate affects the repair of pyrimidine dimers. The opposite results are observed for u.v.-mutagenesis in Chinese hamster V79 cells. The presence of ascorbate (50 micrograms/ml) during u.v. irradiation does not enhance the u.v. effect, but rather decreases it approximately 30%. These results are discussed with regard to differences in the mechanism of u.v.-mutagenesis and DNA repair in bacterial and mammalian cells

134

Electrochemical examination of the ascorbic acid radical anion in non-aqueous electrolytes  

International Nuclear Information System (INIS)

A quasi-reversible redox reaction involving ascorbic acid was observed in non-aqueous electrolytes at conductive diamond electrode. The chemical reversibility of these reactions is consistent with ascorbic acid being reduced to the ascorbic acid radical anion in a one-electron process, with subsequent reoxidation to ascorbic acid. This is the first report on the electrochemical production of the ascorbic acid radical anion in non-aqueous electrolytes. Ascorbyl 6-stearate and 4-hydroxy 2(5H)-furanone, which have somewhat similar structures as ascorbic acid, also showed one-electron transfer reduction reaction producing radicals with a single negative charge, suggesting that these compounds follow the same electrochemical behavior as ascorbic acid. The double bond and hydroxyl substituent on the five-membered ring are shown to be necessary for the stabilization of the radical anions. It was confirmed by the calculation of the total energy using molecular orbital methods that resonance structures involving the double-bond and hydroxyl group provide significant stabilization of the radical anions. Electrochemical preparation may be a useful method for the detailed study of radicals, their molecular structure and reactivity

135

Electrochemical examination of the ascorbic acid radical anion in non-aqueous electrolytes  

Energy Technology Data Exchange (ETDEWEB)

A quasi-reversible redox reaction involving ascorbic acid was observed in non-aqueous electrolytes at conductive diamond electrode. The chemical reversibility of these reactions is consistent with ascorbic acid being reduced to the ascorbic acid radical anion in a one-electron process, with subsequent reoxidation to ascorbic acid. This is the first report on the electrochemical production of the ascorbic acid radical anion in non-aqueous electrolytes. Ascorbyl 6-stearate and 4-hydroxy 2(5H)-furanone, which have somewhat similar structures as ascorbic acid, also showed one-electron transfer reduction reaction producing radicals with a single negative charge, suggesting that these compounds follow the same electrochemical behavior as ascorbic acid. The double bond and hydroxyl substituent on the five-membered ring are shown to be necessary for the stabilization of the radical anions. It was confirmed by the calculation of the total energy using molecular orbital methods that resonance structures involving the double-bond and hydroxyl group provide significant stabilization of the radical anions. Electrochemical preparation may be a useful method for the detailed study of radicals, their molecular structure and reactivity.

Yoshimura, M.; Honda, K.; Kondo, T.; Rao, T.N.; Tryk, D.A.; Fujishima, A

2002-10-15

136

Effects of ascorbic acid and antioxidants on color, lipid oxidation and volatiles of irradiated ground beef  

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Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% {alpha}-tocopherol, or 0.1% ascorbic acid+0.01% sesamol+0.01% tocopherol. The meats were packaged in oxygen-permeable bags, irradiated at 2.5 kGy, and color, oxidation-reduction potential (ORP), lipid oxidation and volatile profiles were determined. Irradiation decreased the redness of ground beef, and visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During aerobic storage, S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol+{alpha}-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol+tocopherol in irradiated ground beef was superior to that of ascorbic acid.

Ahn, D.U. E-mail: duahn@iastate.edu; Nam, K.C

2004-10-01

137

Ascorbic acid antagonizes nicotine-induced place preference and behavioral sensitization in female mice  

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Full Text Available Introduction: The influence of ascorbic acid on the nicotine-induced conditioned place preference (CPP and behavioral sensitization was investigated in the present study. Methods: In a pilot study, place conditioning and locomotor activity were investigated after nicotine (0.25, 0.5, 0.75, 1, 1.5 and 2 mg/kg or ascorbic acid (1, 10, 100 and 1000 mg/kg administration. Different doses of ascorbic acid in conditioning days or on the test days were used. Behavioral sensitization was induced in animals by daily intraperitoneal administration of nicotine (0.25 mg/kg for seven cosecutive days followed by one day interval. On 9th day, locomotor activity was induced by ineffective dose of nicotine (0.1 mg/kg. Ascorbic acid was injected 20 min before each injection of nicotine (acquisition of sensitization or acutely 20 min before a challenge nicotine injection (expression of sensitization. Results: The results showed that intraperitoneal nicotine (1 mg/kg administration can induce place preference whereas acute administration of the drug induces catalepsy. Administration of ascorbic acid did not induce place preference nor place aversion and also did not change the locomotor activity. Locomotor sensitization in mice was produced by intraperitoneal injection of nicotine (0.25 mg/kg for 7 consecutive days. On the 9th day of experiments, activity of the mice was recorded after challenge with nicotine (0.1 mg/kg, i.p.. The senisitization was better achived when the ineffective dose of nicotine (0.1 mg/kg was applied. Administration with ascorbic acid reduced both the acquisition and expression of nicotine-induced CPP. It was shown that ascorbic acid attenuated the acquisition of nicotine sensitization in a dose-independent manner but the expression of nicotineinduced sensitization was not affected by ascorbic acid. Conclusion: We conclude that ascorbic acid may interfere with nicotine-induced place preference and behavioral sensitization.

Ali Akbar Aliabadi

2006-04-01

138

INFLUENCES OF THIAMINE AND/OR ASCORBIC ACID ON LEAD INTOXICATION  

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The effects of thiamine, ascorbic acid ami their combination an workers who are continuously exposal to lead has been investigated. In this study 60 persons in a Battery industry was selected and divided into four equal groups. Group I received placebo, group II thiamine (300 mg), group III ascorbic acid (250 mg) anil group IV thiamine (300 mg) plus ascorbic acid (250 mg) three times a day (Orally). At beginning of the study and after one month of above drug regimen; blood, urine and a questi...

Ghazi-khansari, M.; Hajighasemkhan, A.; Ghazaie, S.

1996-01-01

139

Effect of ascorbic acid concentrations, methods of cooling and freezing on Boer goat semen cryopreservation.  

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To improve the Boer goat semen quality during cryopreservation process, three experiments were carried out to investigate the effect of (i) different concentration of ascorbic acid supplementation (ii) rate of cooling with chilled semen characteristics and (iii) method of freezing on post-thaw Boer goat sperm using Tris-based extender. Ascorbic acid at 8.5 mg/ml improved the sperm parameters (motility, integrity of membrane and acrosome, morphology and viability), compared to control in cooled samples (p goat sperm freezing (p Boer goat was improved when a Tris-based extender supplemented with ascorbic acid was used at stages of different cooling rates and freezing methods. PMID:22909427

Memon, A A; Wahid, H; Rosnina, Y; Goh, Y M; Ebrahimi, M; Nadia, F M

2013-04-01

140

Reduction of hexavalent chromium by ascorbic acid in aqueous solutions.  

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Hexavalent chromium is a priority pollutant in the USA and many other countries. Reduction of Cr(VI) to Cr(III) is environmentally favorable as the latter species is not toxic to most living organisms and also has a low mobility and bioavailability. Reduction of Cr(VI) by ascorbic acid (vitamin C) as a reductant was studied using potassium dichromate solution as the model pollutant. Effects of concentration of vitamin C, pH, temperature, irradiation and reaction time on the reduction of Cr(VI) were examined. Cr(VI) might be reduced by vitamin C not only in acidic conditions but also in weakly alkaline solutions. The reduction of Cr(VI) by vitamin C might occur not only under irradiation but also in the dark. Vitamin C is an important biological reductant in humans and animals, and not toxic. It is water-soluble and can easily permeate through various types of soils. The results indicate that vitamin C could be used in effective remediation of Cr(VI)-contaminated soils and groundwater in a wide range of pH, with or without sunlight. PMID:15488923

Xu, Xiang-Rong; Li, Hua-Bin; Li, Xiao-Yan; Gu, Ji-Dong

2004-11-01

 
 
 
 
141

Pre-sowing application of ascorbic acid and salicylic acid to seed of pumpkin and seedling response to salt  

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The effects of seed soaking with salicylic acid or ascorbic acid on pumpkin seedlings growth under saline (10 dS m/sup -1/) conditions were investigated. Seedlings fresh weight, protein contents, protease and nitrate reductase activities were significantly affected by 15 and 30 mg L/sup -1/ salicylic acid and 30 mg L/sup -1/ ascorbic acid priming treatments, under both normal and saline conditions. Priming reduced the severity of the salt stress, the amelioration was better due to 30 mg L/sup -1/ ascorbic acid or 30 mg L/sup -1/ salicylic acid treatments as these treatments showed best results on seedling growth, fresh and dry matter production under non-saline and saline environments. Application of seed priming with ascorbic acid and salicylic acid in pumpkin ameliorate the adverse effects of salt stress. (author)

142

Modulation of ascorbic acid-induced DNA cleavage by polyamide: cleavage manner, kinetics and mechanism.  

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Manipulation of DNA presents a great interest in biotechnology and therapeutics. The molecules that damage DNA selectively offer new prospects for controlled manipulation of DNA. The conjugations of DNA-code reading molecules such as polyamides to reagents that induce DNA damages provide an approach to reach this goal. In this work, a new compound which contained polyamide and ascorbic acid conjugated by flexible linker (polyamide-Vc), was successfully synthesized, characterized, and evaluated as DNA cleavage agent, compared with that by using ascorbic acid molecule. The kinetics data showed that polyamide-Vc successfully promoted the cleavage of plasmid DNA, with k(max) of 0.314 h(-1) and K(d) of 0.105 mM. The evaluation of DNA linearization elicited that the activity of cleaving double-strand in the supercoiled pUC18 plasmid DNA by polyamide-Vc was enhanced remarkably, achieving n1/n2 ratio of 13.9 at 1.2 mM for 1 h. The introduction of polyamide to Vc could also partially weaken the inhibition of hydrogen radical to double-strand cleavage process because of its good binding activity to DNA. We anticipate that this work could provide a method for improving the efficiency of double-strand cleavage, especially to oxidative cleavage agents. PMID:22214457

Li, C; Duan, S; Xu, J; Qiao, R; Xu, P; Zhao, Y

2012-01-01

143

Ascorbic Acid Blocks Hyperglycemic Impairment of Endothelial Function in Adolescents with Type 1 Diabetes  

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Objective To determine whether acute acorbic acid infusions alters the effect of hyperglycemia on endothelial function in adolescents with type 1 diabetes. Research Design and Methods The forearm blood flow (FBF) reactive hyperemic response to 5 min of upper arm occlusion was studied in 8 adolescents with type 1 diabetes during euglycemic and hyperglycemic insulin clamp (40 mU/m2/min) with and without ascorbic acid infusion (3 mg/min). Results The ratio of post-occlusion to pre-occlusion FBF decreased during hyperglycemia without ascorbic acid (p=0.013) but did not change during hyperglycemia with ascorbic acid. The changes during hyperglycemia were different between the two studies (p=0.038). Similar results were found when the percent change in forearm vascular resistance following occlusion was assessed. Conclusions These results indicate that antioxidant treatment with ascorbic acid blocks acute hyperglycemic impairment of endothelial function in adolescents with type 1 diabetes. PMID:22925199

Hoffman, Robert P.; Dye, Amanda S.; Bauer, John A.

2012-01-01

144

Kinetics of Ascorbic Acid Degradation in Un-Pasteurized Iranian Lemon Juice During Regular Storage Conditions  

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Full Text Available The aim of this research was to determine shelf life stability of un-pasteurized lemon juice filled in clear or dark green glass bottles. Presence of light, time and temperature affect the ascorbic acid retention in citrus juices. Bottles were stored at room temperature (27 ± 3 °C and in the refrigerator (3 ± 1 °C. Total soluble solids, total titrable acidity and pH value were measured every three weeks and analysis was carried out on ascorbic acid content by means of titration method in the presence of 2,6-dichlorophenol indophenol. The study was carried out for 12 weeks after which slight changes in color, taste and apparent texture in some samples were observed and ascorbic acid content reduced by 50%. Soluble solids content, pH value and total acidity were 5.5 ° Brix, 2.73 and 5 g/100 mL, respectively which appeared not to be significantly influenced by storage time or conditions. Ascorbic acid content initially at 38.50 mg/100 mL was sharply reduced to about 22 mg/100 mL within the first three weeks of storage. The final ascorbic acid content of all samples was about 15 mg/100 mL. The deteriorative reaction of ascorbic acid in the juice at all conditions followed a first-order kinetic model with activation energy of 137 cal mol-1.

Abbasi

2008-01-01

145

Ascorbic Acid Interaction With Analgesic Effect of Morphine and Tramadol in Mice  

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Background: Combining different analgesic drugs for improvement of drug efficacy is a recommended strategy intended to achieve the optimal therapeutic effects. Objectives: The purpose of the present study was to assess the nature of the interaction between ascorbic acid and two analgesic drugs, morphine and tramadol. Materials and Methods: The analgesic activity was assessed by the acetic acid writhing test in male Naval Medical Research Institute (NMRI) mice. The results were obtained using four to six animals in each group. All the drugs were injected intraperitoneally. The effective doses (ED) that produced 20%, 50%, and 65% antinociception (ED20, ED50 and ED65) were calculated from the dose-response curve of each drug alone as well as co-administration of ascorbic acid and tramadol or morphine. The interaction index was calculated as experimental ED/theoretical ED. For each drug combination, ED50, ED20 and ED65 were determined by linear regression analysis of the dose-response curve, and they were compared to theoretical ED50, ED20 and ED65 using t-test. Results: The antinociceptive effects of all drugs were dose-dependent (ED50was 206.1 mg/kg for ascorbic acid, 8.33 mg/kg for tramadol, and 0.79 mg/kg for morphine). The interaction index demonstrated additive effects at ED50 and ED65 for co-administration of ascorbic acid and tramadol or morphine. However, at ED20, combination of ascorbic acid and tramadol or morphine showed synergic effects. The interaction index values of the combinations demonstrated the potency ratio of ascorbic acid/morphine to be lower than ascorbic acid/tramadol. Conclusions: This study demonstrated the results of interactions between ascorbic acid and tramadol or morphine. The results showed that the interaction effects on antinociception may be synergistic or additive, depending on the level of effect.

Zeraati, Fatemeh; Araghchian, Malihe; Farjoo, Mohammad Hadi

2014-01-01

146

Enthalpic characteristics of interactions occurring between an ascorbic acid and some saccharides in aqueous solutions  

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The enthalpies of solution of mono- and disaccharides were measured in water and aqueous ascorbic acid solutions at 298.15 K using a calorimeter of solution. Enthalpies of transfer of saccharides from water to aqueous ascorbic acid solutions were derived, and enthalpic coefficients of pair interaction hxy were calculated according to MacMillan-Mayer theory. Interactions of ascorbic acid with D-fructose and sucrose are energetically favorable and characterized by negative hxy coefficients while hxy for the interactions occurring between ascorbic acid and ?-D glucose, D-galactose and maltose are positive. The obtained results are interpreted in terms of the influence of structure and solvation of solutes on the thermodynamic parameters of their interaction in solutions

147

Study of Ascorbic Acid as Iron(III Reducing Agent for Spectrophotometric Iron Speciation  

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Full Text Available The study of ascorbic acid as a reducing agent for iron(III has been investigated in order to obtain an alternative carcinogenic reducing agent, hydroxylamine, used in spectrophotometric standard method based on the formation of a red-orange complex of Fe(II-o-phenanthroline. The study was optimised with regards to ascorbic acid concentration as well as pH solution. The results showed that ascorbic acid showed maximum capacity as reducing agent of iron(III under concentration of 4.46.10-4 M and pH solution of 1-4.Under these conditions, ascorbic acid reduced iron(III proportionally and performed similarly to that of hydroxylamine.  The method gave result to linear calibration over the range of 0.2-2 mg/L withhigh accuracy of 97 % and relative standard deviation of less than 2 %. This method was successfully applied to assay iron speciation in water samples.

Antesar Elmagirbi

2012-10-01

148

Enthalpic characteristics of interactions occurring between an ascorbic acid and some saccharides in aqueous solutions  

Energy Technology Data Exchange (ETDEWEB)

The enthalpies of solution of mono- and disaccharides were measured in water and aqueous ascorbic acid solutions at 298.15 K using a calorimeter of solution. Enthalpies of transfer of saccharides from water to aqueous ascorbic acid solutions were derived, and enthalpic coefficients of pair interaction h{sub xy} were calculated according to MacMillan-Mayer theory. Interactions of ascorbic acid with D-fructose and sucrose are energetically favorable and characterized by negative h{sub xy} coefficients while h{sub xy} for the interactions occurring between ascorbic acid and {alpha}-D glucose, D-galactose and maltose are positive. The obtained results are interpreted in terms of the influence of structure and solvation of solutes on the thermodynamic parameters of their interaction in solutions.

Terekhova, Irina V.; Kulikov, Oleg V.; Titova, Elena S

2004-03-23

149

Ascorbic acid for the treatment of methemoglobinemia: the experience of a large tertiary care pediatric hospital.  

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The purpose of reporting this series of patients is to illustrate the role of ascorbic acid in the treatment of severe acquired methemoglobinemia (metHb), especially when methylene blue is not available. Medical records of affected patients were reviewed to collect history of exposures, food ingestion, physical examination, pulse oximetry, blood gas, and co-oximetry results, and outcomes. Five cases of acquired metHb are presented here, all of whom received treatment with ascorbic acid and fully recovered after 24 hours of treatment. Our series emphasizes that ascorbic acid is an effective alternative in the management of acquired metHb if methylene blue is unavailable and suggests that ascorbic acid infusion may be indicated in patients with glucose-6-phosphatase dehydrogenase deficiency. PMID:24914501

Rino, Pedro Bonifacio; Scolnik, Dennis; Fustiñana, Ana; Mitelpunkt, Alexis; Glatstein, Miguel

2014-01-01

150

Chemical Characterization and Evolution of Ascorbic Acid Concentration During Dehydration of Rosehip (Rosa eglanteria Fruits  

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Full Text Available Rose hip fruits possess a high ascorbic acid content, which may partially degrade during dehydration in heated air. In this study, the chemical composition of the fruits was determined in order to study degradation of ascorbic acid as a function of drying temperature. The results indicated that, in effect, the content of this nutrient is reduced. The degradation mechanisms differed according to the drying temperature but the final ascorbic acid content was almost independent from such operating variable. The experimental evidence was used to calculate the degradation kinetic parameters. Though the extent of degradation was important, the final retention of ascorbic acid was considerable (42% in view of the high initial content for this fruit.

Antonio De Michelis

2007-01-01

151

Induction of monozygotic twinning by ascorbic acid in tobacco.  

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Embryo development in plants initiates following the transverse division of a zygote into an apical, proembryo cell and a basal cell that gives rise to the suspensor. Although mutants affected in embryo development through changes in cell division have been described, little is known about the control of the first zygotic division that gives rise to the proembryo. Ascorbic acid (Asc) promotes cell division by inducing G(1) to S progression but its role in embryo development has not been examined. In this study, we show that the level of dehydroascorbate reductase (DHAR) expression, which recycles Asc and regulates Asc pool size, affects the rate of monozygotic twinning and polycotyly. DHAR-induced twinning resulted from altered cell polarity and longitudinal instead of transverse cell division that generated embryos of equal size. Direct injection of Asc into ovaries phenocopied DHAR-induced twinning. Twinning induced by Asc was developmentally limited to the first two days after pollination whereas polycotyly was induced when the level of Asc was elevated just prior to cotyledon initiation. This work describes the first example of gene-directed monozygotic twinning and shows that Asc regulates cell polarity during embryo development. PMID:22723952

Chen, Zhong; Gallie, Daniel R

2012-01-01

152

Role of ascorbic acid against pathogenesis in plants  

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Full Text Available Plants vary considerably in their physiological response to various kinds of environmental stress. To prevent damage caused by pathogenic attack and to acclimate to change in their environment, plants have evolved direct and indirect mechanism for sensing and responding to pathogenic stimuli. Ascorbic acid (AA is found in all eukaryotes including animals and plants and lack completely in prokaryotes except cyanobactaria, have been reported to have a small amount. AA has now gained significant place in plant science, mainly due to its properties (antioxidant and cellular reductant etc., and multifunctional roles in plant growth, development, and regulation of remarkable spectrum of plant cellular mechanisms against environmental stresses. As it is evident from the present review, recent progress on AA potentiality in tolerance of plants to pathogenic attack has been impressive to a greater extent. AA produced in plants as indirect response against pathogenic attack at different sites in plants and its intertwined network cause changes in nuclear gene expression via retrograde signaling pathways, or even into systemic responses, all of which are associated with pathogenic resistance. Indeed, AA plays an important role in resistance to pathogenesis.

Taqi Ahmed Khan

2011-09-01

153

Effects of ascorbic acid on stress and disease in chickens.  

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White leghorn chickens were given feed containing 100 mg of ascorbic acid (AA)/kg. One day later, treated chickens and a similar group of unmedicated control chickens were chilled for 1 hour at 6 C, exposed to an unusual sound, fasted, or subjected to rough handling. Heterophil:lymphocyte (H:L) ratios were determined one day later. The AA-treated birds had significantly lower H:L ratios than untreated controls. Chickens that received a diet containing AA had lower H:L ratios than controls (0.86 vs. 1.65) following administration of adrenocorticotropic hormone. Chickens fed a diet containing AA showed increased resistance to a combined Newcastle disease virus-Mycoplasma gallisepticum infection and to a secondary Escherichia coli infection, as well as to a primary E. coli challenge infection. The effects of AA and an antibacterial drug (furaltadone) were additive. In all experiments, the optimum dose of AA was 100 mg/kg of feed. There was a negative correlation between AA level in the diet and feed efficiency. PMID:1417599

Gross, W B

1992-01-01

154

ESR study of ascorbic acid irradiated with gamma-ray  

International Nuclear Information System (INIS)

The interest in application of high-energy ionizing radiation for sterilization of pharmaceutical products and foodstuffs has led a number of workers to investigate the radiation sensitivity of vitamins. Aside from its use as a vitamin, ascorbic acid (AA) or some derivatives are employed as antioxidants in foodstuffs. The effects of ionizing radiation on AA in simple solutions and in mixture of naturally occurring compounds have been extensively reported in the literature. However, the effects of ionizing radiation on solid AA were reported in few works which described rather dosimetric features of AA. No reports, except one, are available describing the characteristic features of the radiolytic intermediates produced after irradiation of polycrystalline AA. Irradiation studies performed on single crystal of AA has led us to reinvestigate our previous work on the radiolytic intermediates produced in irradiated polycrystalline AA. Three radical species, rather than two, having different characteristics were decided contributing to the formation of experimental electron spin resonance (ESR) spectrum of ?-irradiated polycrystalline AA. Spectral parameters of these species were calculated after exhaustive spectrum simulation calculations based on data derived from experimental microwave saturation and dose-response studies. (author)

155

Intravenous ascorbic acid as an adjuvant to interleukin-2 immunotherapy.  

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Interleukin-2 (IL-2) therapy has been demonstrated to induce responses in 10-20% of advanced melanoma and renal cell carcinoma patients, which translates into durable remissions in up to half of the responsers. Unfortunately the use of IL-2 has been associated with severe toxicity and death. It has been previously observed and reported that IL-2 therapy causes a major drop in circulating levels of ascorbic acid (AA). The IL-2 induced toxicity shares many features with sepsis such as capillary leakage, systemic complement activation, and a relatively non-specific rise in inflammatory mediators such as TNF-alpha, C-reactive protein, and in advanced cases organ failure. Animal models and clinical studies have shown rapid depletion of AA in conditions of sepsis and amelioration associated with administration of AA (JTM 9:1-7, 2011). In contrast to other approaches to dealing with IL-2 toxicity, which may also interfere with therapeutic effects, AA possesses the added advantage of having direct antitumor activity through cytotoxic mechanisms and suppression of angiogenesis. Here we present a scientific rationale to support the assessment of intravenous AA as an adjuvant to decrease IL-2 mediated toxicity and possibly increase treatment efficacy. PMID:24884532

Wagner, Samuel C; Markosian, Boris; Ajili, Naseem; Dolan, Brandon R; Kim, Andy J; Alexandrescu, Doru T; Dasanu, Constantin A; Minev, Boris; Koropatnick, James; Marincola, Francesco M; Riordan, Neil H

2014-01-01

156

Ascorbic acid iontophoresis for chondral gain in rats with arthritis  

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OBJECTIVES: To examine the cellularity and thickness of the articular cartilage of the femur in rats with arthritis after treatment with iontophoresis. METHODS: To evaluate these objectives, a histological analysis was performed on hematoxylin and eosin, where cellularity and cartilage thickness were observed and evaluated qualitatively and quantitatively by manual counting by 700.09µm² area. RESULTS: The group treated with IAA had normal cellularity (40.1 cells/?m2) and maintenance of non-calcified cartilage (75.5?m), suggesting normal thickness. The non-treated group C+, on the other hand, had a lower mean number of chondrocytes (13.0?m2) (P <0.05) and, when the cartilage thickness was compared, it showed higher average thickness of calcified cartilage (104.8 mm) and lower mean of non-calcified cartilage (53.3?m) CONCLUSION: The use of iontophoresis with L-ascorbic acid by continuous electric current contributed to a quantitative gain of chondrocytes and improved the thickness distribution of calcified and non-calcified cartilage. Level of Evidence III, Case Control Study. PMID:25246850

de Arruda, Mauricio Ferraz; Cassettari, Lucas Langoni; Neves, Lais Mara Siqueira das; Oliveira, Olga Maria Mascarenhas de Faria; Marcolino, Alexandre Marcio

2014-01-01

157

Development of Calibration and Standard Addition Polarographic Determination of Ascorbic Acid  

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Full Text Available Aims: Effect of pH on polarographic waves of ascorbic acid were studied by recording polarograms of ascorbic acid solution, between 0 to 400 mV at different pH (0.065 to 9.6 using 0.008% solution of gelatin and 0.05 M potassium hydrogen phthalate buffer (containing 0.25% oxalic acid as maxima suppressor and supporting electrolyte respectively. Methods: Ascorbic acid is strong reducing agent and produces an anodic wave which shifts with pH. There is no significant change in height of wave with change in pH from 2.25 to 4.85. For determination of ascorbic acid pH 4.0 is chosen. Ascorbic acid present in synthetic sample is determined by calibration, external standard addition and internal standard addition methods. The results obtained are in good agreement with the quoted values. Result: The number of electrons taking part in the reversible reaction is found to be 2. The half-wave potential is found to be independent of the ascorbic acid concentration

Swaroopa Rani N. Gupta

2015-04-01

158

Effects of ascorbic acid on sperm motility, viability, acrosome reaction and DNA integrity in teratozoospermic samples  

Science.gov (United States)

Background: Oxidative stress in teratozoospermic semen samples caused poor assisted reproductive techniques (ART) outcomes. Among antioxidants, ascorbic acid is a naturally occurring free radical scavenger and as such its presence assists various other mechanisms in decreasing numerous disruptive free radical processes. Objective: The main goal of this study was to evaluate potential protective effects of ascorbic acid supplementation during in vitro culture of teratozoospermic specimens. Materials and Methods: Teratozoospermic semen samples that collected from 15 volunteers were processed, centrifuged and incubated at 37oC until sperm swimmed-up. Supernatant was divided into four groups and incubated at 37oC for one hour under different experimental conditions: Control, 10 µm A23187, 600µm ascorbic acid and 10 µm A23187+600 µm ascorbic acid. After incubation sperm motility, viability, acrosome reaction, DNA damage and malondialdehyde levels were evaluated. Results: Our results indicated that after one hour incubation, ascorbic acid significantly reduced malondialdehyde level in ascorbic acid group (1.4±0.11 nmol/ml) compared to control group (1.58±0.13 nmol/ml) (p<0.001). At the end of incubation, progressive motility and viability in ascorbic acid group (64.5±8.8% and 80.3±6.4%, respectively) were significantly (p<0.05 and p<0.001, respectively) higher than the control group (54.5±6.8% and 70.9±7.3%, respectively). A23187 significantly (p<0.0001) increased acrosome reaction in A23187 group (37.3±5.6%) compared to control group (8.5±3.2%) and this effect of A23187 attenuated by ascorbic acid in ascorbic acid+A23187 group (17.2±4.4%). DNA fragmentation in ascorbic acid group (20±4.1%) was significantly (p<0.001) lower than controls (28.9±4.6%). Conclusion: In vitro ascorbic acid supplementation during teratozoospermic semen processing for ART could protect teratozoospermic specimens against oxidative stress, and it could improve ART outcome. PMID:24799867

Fanaei, Hamed; Khayat, Samira; Halvaei, Iman; Ramezani, Vahid; Azizi, Yaser; Kasaeian, Amir; Mardaneh, Jalal; Parvizi, Mohammad Reza; Akrami, Maryam

2014-01-01

159

Histochemical observation and cellular distribution of ascorbic acid in persimmon leaves.  

Science.gov (United States)

This study was carried out to resolve the discrepancy of data for the proportion of ascorbic acid and dehydroascorbic acid in persimmon leaves at the final stage of the season and to clarify their cellular distributions using histochemical and biochemical techniques. Fresh persimmon leaves were collected and used on July 31, September 5 and October 7, 1996. Ascorbic acid and dehydroascorbic acid in subcellular fractions were determined by the HPLC method that was found to be the most reliable for separation. The percent of dehydroascorbic acid in the total leaves was found to be almost constant (between 32 and 37%) in all preparations tested. In all preparations, more than 90% of the ascorbic acid and dehydroascorbic acid was found in the soluble fraction. The histochemical detection of ascorbic acid and an electron micrograph of persimmon leaf cells showed that the reactive color, after the reduction of silver nitrate under acidic conditions, in the leaves of all three preparations was mainly found on the face side of columned-type palisade parenchyma cells where chloroplasts were not rich and large vacuoles were seen. On the inner side of the palisade parenchyma cells where chloroplasts were the richest, only weak color development was observed. This study demonstrates that the percent of dehydroascorbic acid in persimmon leaves did not exceed 40% at least until October 7. It also shows that in persimmon leaf cells, ascorbic acid is mainly localized in the cytosol of palisade parenchyma tissue cells where large vacuoles are seen. PMID:9591230

Kusunoki, K; Hara, T; Fujita, M; Minari, Y; Tadokoro, T; Innami, S; Maekawa, A

1998-02-01

160

Evaluation of mineral elements and ascorbic acid contents in fruits of some wild plants.  

Science.gov (United States)

The fruits of some wild plants were examined for their contents of mineral elements and ascorbic acid. High levels of ascorbic acid were found in fruits of Sclerocarya birrea (403.3 mg/100 g) and Adansonia digitata (337 mg/100 g). In nine of the fruits examined, the mineral contents (Ca, P) were comparable with average values found in common fruits. The iron contents were however 2-5 times higher than the values for common fruits. PMID:1852726

Eromosele, I C; Eromosele, C O; Kuzhkuzha, D M

1991-04-01

 
 
 
 
161

Depletion of Ascorbic Acid Restricts Angiogenesis and Retards Tumor Growth in a Mouse Model  

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Angiogenesis requires the deposition of type IV collagen by endothelial cells into the basement membrane of new blood vessels. Stabilization of type IV collagen triple helix depends on the hydroxylation of proline, which is catalyzed by the iron-containing enzyme prolyl hydroxylase. This enzyme, in turn, requires ascorbic acid to maintain the enzyme-bound iron in its reduced state. We hypothesized that dietary ascorbic acid might be required for tumor angiogenesis and, therefore, tumor growth...

Telang, Sucheta; Clem, Amy L.; Eaton, John W.; Chesney, Jason

2007-01-01

162

The Action of Ascorbic Acid on Collagen as a Protective System Against Ultra-Violet Irradiation  

International Nuclear Information System (INIS)

The real action of ascorbic acid as a protective system on collagen upon ultra-violet (UV) irradiation has been shown by electron spin resonance (ESR) method. The received results are in a good agreement with the data obtained by thermodynamic studies and clarify them. Ascorbic acid is represented as a free radical scavenger which protects protein against the appearance of secondary radicals and also reduces structural damages. (authors)

163

Natural origin of ascorbic acid: validation by 13C-NMR and GC-C-IRMS  

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A new method for the extraction and purification of ascorbic acid from two tropical fruits (acerola and camu-camu) is presented. 13C nuclear magnetic resonance and isotopic ratio mass spectroscopy (13C/12C) were used to recognize ascorbic acid coming from either natural or industrial sources. A quantitative 13C NMR procedure was optimized to calculate isotopic relative abundances on each molecular site; data were treated by a multivariate method. Samples were also analysed by I...

Cravotto, Giancarlo; Vincenti, Marco; Gobetto, Roberto; Albertino, Andrea; Barge, Alessandro

2009-01-01

164

Preventive activity of ascorbic acid on lead acetate induced cerebellar damaged in adult Wistar rats  

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Among the environmental contaminants, lead is one of the most hazardous to living matter. In mammals, the main target is the central nervous system, particularly in the young. Ascorbic acid is an antioxidant which is a substance that may protect your cells against the effects of free radicals. This study investigated Experiment the protective effect of ascorbic acid on the cerebellum of adult Wistar rats following oral administration of different doses of Lead acetate. Thirty adult Wistar rat...

Sunday Abraham Musa; Iliyasu Musa Omoniye; Wilson Oliver Hamman; Augustine Oseloka Ibegbu; Uduak Emmanuel Umana

2012-01-01

165

Ascorbic acid and salicylic acid mitigate nacl stress in Caralluma tuberculata Calli.  

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Plants exposed to salt stress undergo biochemical and morphological changes even at cellular level. Such changes also include activation of antioxidant enzymes to scavenge reactive oxygen species, while morphological changes are determined as deformation of membranes and organelles. Present investigation substantiates this phenomenon for Caralluma tuberculata calli when exposed to NaCl stress at different concentrations. Elevated levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) in NaCl-stressed calli dwindled upon application of non-enzymatic antioxidants; ascorbic acid (AA) and salicylic acid (SA). Many fold increased enzymes concentrations trimmed down even below as present in the control calli. Electron microscopic images accentuated several cellular changes upon NaCl stress such as plasmolysed plasma membrane, disruption of nuclear membrane, increased numbers of nucleoli, alteration in shape and lamellar membrane system in plastid, and increased number of plastoglobuli. The cells retrieved their normal structure upon exposure to non-enzymatic antioxidants. The results of the present experiments conclude that NaCl aggravate oxidative molecules that eventually alleviate antioxidant enzymatic system. Furthermore, the salt stress knocked down by applying ascorbic acid and salicylic acid manifested by normal enzyme level and restoration of cellular structure. PMID:24744157

Rehman, Riaz Ur; Zia, Muhammad; Abbasi, Bilal Haider; Lu, Gang; Chaudhary, Muhammad Fayyaz

2014-06-01

166

Quantitative Determination of Citric and Ascorbic Acid in Powdered Drink Mixes  

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A procedure by which the reactions are used to quantitatively determine the amount of total acid, the amount of total ascorbic acid and the amount of citric acid in a given sample of powdered drink mix, are described. A safe, reliable and low-cost quantitative method to analyze consumer product for acid content is provided.

Sigmann, Samuella B.; Wheeler, Dale E.

2004-01-01

167

Effect of alpha-tocopherol and ascorbic acid on bovine in vitro fertilization.  

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The aim of this work was to study the effect of alpha-tocopherol (vitamin E) and ascorbic acid on the in vitro fertilization process. Frozen bovine semen was prepared using extenders with and without addition of vitamin E. Samples were capacitated with heparin in the fertilization medium. In vitro matured oocytes were inseminated with spermatozoa frozen with and without vitamin E and, after thawing, fertilized in TALP medium (control) and in TALP medium with vitamin E (1 mg/ml), with ascorbic acid (5 mM) and with vitamin E plus ascorbic acid. Gametes were incubated in the respective fertilization medium for 48 h; those frozen without vitamin E yielded 75, 76, 69 and 49% of fertilized oocytes in the control, vitamin E, ascorbic acid and vitamin E plus ascorbic acid media, respectively. The last value was significantly different (P bovine sperm frozen with vitamin E, fertilization rates were 74, 50, 47 and 34%, respectively for the 4 groups. Values observed for the different supplements were significantly different inter se (P < 0.01), except between the media with vitamin E and with ascorbic acid. These results indicate that preserved antioxidant capacity of vitamin E impairs the success of the in vitro fertilization process. PMID:10732040

Dalvit, G C; Cetica, P D; Beconi, M T

1998-02-01

168

Application of titanium oxide nanotube films containing gold nanoparticles for the electroanalytical determination of ascorbic acid  

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Au/TiO2/Ti electrodes have been prepared by galvanic deposition of gold particles on TiO2 nanotube substrates. Titanium oxide nanotubes are fabricated by anodizing titanium foil in a Dimethyl Sulfoxide electrolyte containing fluoride. The scanning electron microscopy results indicated that gold particles are homogeneously deposited on the surface of TiO2 nanotubes. The TiO2 layers consist of individual tubes of about 40-80 nm diameters. The electro-catalytic behavior of Au/TiO2/Ti and flat gold electrodes for the ascorbic acid electro-oxidation was studied by cyclic voltammetry. The results showed that the flat gold electrode is not suitable for the oxidation of ascorbic acid. However, the Au/TiO2/Ti electrodes are shown to possess catalytic activity toward the oxidation reaction. Catalytic oxidation peak current showed a linear dependence on the ascorbic acid concentration and a linear calibration curve is obtained in the concentration range of 1-5 mM of ascorbic acid. Also, determination of ascorbic acid in real samples was evaluated. The obtained results were found to be satisfactory. Finally the effects of interference on the detection of ascorbic acid were investigated.

169

Application of titanium oxide nanotube films containing gold nanoparticles for the electroanalytical determination of ascorbic acid  

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Au/TiO{sub 2}/Ti electrodes have been prepared by galvanic deposition of gold particles on TiO{sub 2} nanotube substrates. Titanium oxide nanotubes are fabricated by anodizing titanium foil in a Dimethyl Sulfoxide electrolyte containing fluoride. The scanning electron microscopy results indicated that gold particles are homogeneously deposited on the surface of TiO{sub 2} nanotubes. The TiO{sub 2} layers consist of individual tubes of about 40-80 nm diameters. The electro-catalytic behavior of Au/TiO{sub 2}/Ti and flat gold electrodes for the ascorbic acid electro-oxidation was studied by cyclic voltammetry. The results showed that the flat gold electrode is not suitable for the oxidation of ascorbic acid. However, the Au/TiO{sub 2}/Ti electrodes are shown to possess catalytic activity toward the oxidation reaction. Catalytic oxidation peak current showed a linear dependence on the ascorbic acid concentration and a linear calibration curve is obtained in the concentration range of 1-5 mM of ascorbic acid. Also, determination of ascorbic acid in real samples was evaluated. The obtained results were found to be satisfactory. Finally the effects of interference on the detection of ascorbic acid were investigated.

Hosseini, Mir Ghasem, E-mail: mg-hosseini@tabrizu.ac.ir; Faraji, Masoud; Momeni, Mohamad Mohsen

2011-03-31

170

Effects of ascorbic acid on some physiological changes of pepino (Solanum muricatum Ait.) under chilling stress.  

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In this study, the changes caused by chilling stress on some physiological parameters of pepino (Solanum muricatum Ait.) plant and the effects of ascorbic acid (100 mM) applied exogenously on these changes were examined. For this purpose, the photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophylls and carotenoids), ascorbic acid, total phenolic compounds, malondialdehyde and proline contents in leaves of pepino taken on 5th and 10th days were determined. As a result of chilling stress, it was found that while the photosynthetic pigments and proline contents decreased in pepino leaves, the ascorbic acid, total phenolic compounds and malondialdehyde contents increased. In plants which were subjected to pre-treatment of ascorbic acid on the 10th day of stress, ascorbic acid and proline contents increased while a decrease was observed in malondialdehyde content, compared to stress group without pre-treated. This study may be important for explaining resistance induced by treatment of exogenous ascorbic acid in pepino exposed to chilling stress. PMID:25194734

Sivaci, Aysel; Kaya, A; Duman, Sevcan

2014-09-01

171

A Highly Sensitive Kinetic Spectrophotometric Method for the Determination of Ascorbic Acid in Pharmaceutical Samples  

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In this study, a new reaction system for quantitative determination of ascorbic acid was introduced. The developed method is based on inhibitory effect of ascorbic acid on the Orange G-bromate system. The change in absorbance was followed spectrophotometrically at 478 nm. The dependence of sensitivity on the reaction variables including reagents concentration, temperature and time was investigated. Under optimum experimental conditions, calibration curve was linear over the range 0.7 – 33.5 ?g mL-1 of ascorbic acid including two linear segments and the relative standard deviations (n = 6) for 5.0 and 20.0 ?g mL–1 of ascorbic acid were 1.08 and 1.02%, respectively. The limit of detection was 0.21 ?g mL?1 of ascorbic acid. The effect of diverse species was also investigated. The developed method was successfully applied for the determination of ascorbic acid in pharmaceutical samples. The results were in a good agreement with those of reference method. PMID:25237333

Shishehbore, Masoud Reza; Aghamiri, Zahra

2014-01-01

172

Effect of Supplemental Ascorbic Acid on the Aerobic Capacity in Children  

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Full Text Available Introduction: ascorbic acid is a water-soluble vitamin solved in water that acts as a helper of some the enzymes in the reactions of energy metabolism. Thus, the study aims to investigate the use of supplemental ascorbic acid on the aerobic and anaerobic capacity of the children.Methodology: Participants of this quasi-experimental study were 18 children in Esfahan who were randomly selected and divided into 9 groups in pair (aerobic exercise group and the control group. For 10 days before the start of the main trial, the participants in the control group received placebo and the experimental group received ascorbic acid. The average aerobic capacity was measured before and after 10 days of the use of ascorbic acid. The results were analyzed by SPSS version 18.Results: Before and after 10 days of the use of ascorbic acid, the mean and standard deviation of the aerobic capacity of the experimental group were respectively 3.59± 0.38 and 4.23 ± 0.77 and of the control group were 3.7 ± 0.40 and 3.7± 0.53, respectively. Therefore, there was a significant relationship between the use of ascorbic acid and placebo in terms of aerobic capacity (p ? 0.5.

Gholamreza Sharifi

2014-10-01

173

Antagonism between abscisic acid and gibberellins is partially mediated by ascorbic acid during seed germination in rice.  

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The antagonism between abscisic acid (ABA) and gibberellin (GA) plays a key role in controlling seed germination, but the mechanism of antagonism during this process is not known. In the associated study, we investigated the relationship among ABA, reactive oxygen species (ROS), ascorbic acid (ASC) and GA during rice seed germination. ROS production is reduced by ABA, which hence results in decreasing ASC accumulation during imbibition. GA accumulation was also suppressed by a reduced ROS and ASC level, whereas application of exogenous ASC can partially rescue seed germination from ABA treatment. Further results show that production of ASC, which acts as a substrate in GA biosynthesis, was significantly inhibited by lycorine which thus suppressed the accumulation of GA. Consequently, expression of GA biosynthesis genes was suppressed by the low levels of ROS and ASC in ABA-treated seeds. These studies reveal a new role for ASC in mediating the antagonism between ABA and GA during seed germination in rice. PMID:22516812

Ye, Nenghui; Zhang, Jianhua

2012-05-01

174

Serum ascorbic acid concentration in patients with acute Falciparum malaria infection: possible significance  

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Full Text Available Falciparum malaria infection is associated with significant destruction of erythrocytes. This leads to the release of toxic metabolic products, including oxidant compounds.We measured the serum concentration of the antioxidant, ascorbic acid, in 129 patients presenting with acute falciparum malaria infection and in 65 healthy individuals. None of the study subjects administered any form of ascorbic acid supplementation within one week prior to participation in this study. The mean serum ascorbate concentration in infected adult males (n = 49, age range 18-50 years was found to be 2.02 ± 0.20 mg/dL, and it was 2.03 ± 0.24 mg/dL in infected adult females (n = 56, age range 18-50 years. These values were significantly greater than the serum ascorbate levels (1.54 ± 0.10 mg/dL in healthy adult males (n = 28 and females (n = 28 (p < 0.05. In children (age range 3 to 5 years, the serum ascorbate concentration was significantly lower (1.95 ± 0.20 mg/dL during infection (n = 25 than in their healthy counterparts (2.9 ± 0.24 mg/dL, n = 9 (p < 0.05. It is evident therefore that ascorbic acid plays a significant role in the pathogenesis of acute falciparum malaria in adults. Infected children also need to be given supplemental doses of ascorbate in view of the weakness of their immune system.

Garba Ibrahim Hassan

2004-10-01

175

Corrosion of PHWR PHT system structural materials by dilute chemical decontamination formulations containing ascorbic acid  

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Decontamination of primary heat transport (PHT) systems of PHWRs is normally carried out using reducing type formulations that contain reducing and complexing agents. Oxalic acid is used as a reductant in many of the commercial and non-commercial formulations. This Paper presents an attempt to evaluate ascorbic acid as a reductant in a chemical formulation. Thermal and radiation stability and corrosion behaviour of ascorbic acid have been evaluated and compared with those for oxalic acid. A formulation containing ethylenediaminetetraacetic acid (EDTA) (400 mg/dm3), ascorbic acid (300 mg/dm3) and citric acid (300 mg/dm3) was evaluated for its compatibility with PHT system construction materials viz. carbon steel, monel-400 and zircaloy-2. (author)

176

Radiation degradation of ascorbic acid, EDTA and citric acid in aqueous solutions  

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Gamma radiolysis of ascorbic acid (AA), EDTA and citric acid (CA) in aqueous solutions indicated that AA and EDTA are more sensitive to radiation than CA. In individual solutions, G(-AA) and G(-EDTA) were determined to be ? 4.4 each whereas G(-CA) was ? 2.2. In irradiated AA solutions, dehydroascorbic acid was the major product with G-value of 4.2. In a mixture, while AA and EDTA underwent radiolytic decomposition, CA was protected. (author). 3 refs., 3 figs

177

Ascorbic acid in cancer chemoprevention: translational perspectives and efficacy.  

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Chemoprevention, which is referred to as the use of nontoxic natural or synthetic chemicals to intervene in multistage carcinogenesis has since decades attracted a considerable interest in plant-derived chemical constituents often termed as "phytochemicals" or sometimes as "Nutraceuticals" in case they are derived from dietary sources. A comprehensive search of the literature show that such an interest in natural product pharmacology has surged in the last 25 years and particularly risen at exponential rates since the last one decade. Phytochemicals such as curcumin (from spice turmeric), resveratrol (from red wine) and genistein (from soy) share the major efforts as indicated by overwhelming publications, despite skepticism concerning their bioavailability. Ascorbic acid (AA), the popular anti-oxidant in fruits and vegetables, has even a longer historical perspective than these dietary agents as for more than 35 years; there had been lingering questions about the efficacy of AA in cancer therapy. The footprints of AA from "scurvy" to "cancer" though complex seems to carry potential provided the puzzle could be set right. The use of AA in cancer treatment has been debated extensively as evident from the literature but surprisingly the complementing early phase bench work on the mechanistic studies for anticancer action was rather retarded. Proposed mechanisms of action for AA in the prevention and treatment of cancer includes antioxidant as well as pro-oxidant properties, stimulation of the immune system, altering carcinogen metabolism, enhancement of collagen synthesis necessary for tumor encapsulation and interference with cancer cell signaling. The observation that the intravenous administration of AA enhances its bioavailability to the extent of deriving pharmacological benefits against cancer has in recent years partially supported the clinical plausibility (efficacy) of AA towards realizing its translational advantage. Here, we provide an overview of AA with regard to its potential in the management of cancer disease. PMID:23140287

Ullah, Mohammad F; Bhat, Showket H; Hussain, Eram; Abu-Duhier, Faisel; Ahmad, Aamir; Hadi, S M

2012-12-01

178

Regulation of L-ascorbic acid content in strawberry fruits.  

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Plants have several L-ascorbic acid (AsA) biosynthetic pathways, but the contribution of each one to the synthesis of AsA varyies between different species, organs, and developmental stages. Strawberry (Fragaria×ananassa) fruits are rich in AsA. The pathway that uses D-galacturonate as the initial substrate is functional in ripe fruits, but the contribution of other pathways to AsA biosynthesis has not been studied. The transcription of genes encoding biosynthetic enzymes such as D-galacturonate reductase (FaGalUR) and myo-inositol oxygenase (FaMIOX), and the AsA recycling enzyme monodehydroascorbate reductase (FaMDHAR) were positively correlated with the increase in AsA during fruit ripening. Fruit storage for 72 h in a cold room reduced the AsA content by 30%. Under an ozone atmosphere, this reduction was 15%. Ozone treatment increased the expression of the FaGalUR, FaMIOX, and L-galactose-1-phosphate phosphatase (FaGIPP) genes, and transcription of the L-galactono-1,4-lactone dehydrogenase (FaGLDH) and FAMDHAR genes was higher in the ozone-stored than in the air-stored fruits. Analysis of AsA content in a segregating population from two strawberry cultivars showed high variability, which did not correlate with the transcription of any of the genes studied. Study of GalUR protein in diverse cultivars of strawberry and different Fragaria species showed that a correlation between GalUR and AsA content was apparent in most cases, but it was not general. Three alleles were identified in strawberry, but any sequence effect on the AsA variability was eliminated by analysis of the allele-specific expression. Taken together, these results indicate that FaGalUR shares the control of AsA levels with other enzymes and regulatory elements in strawberry fruit. PMID:21561953

Cruz-Rus, Eduardo; Amaya, Iraida; Sánchez-Sevilla, José F; Botella, Miguel A; Valpuesta, Victoriano

2011-08-01

179

Synthesis of L-ascorbic acid in the phloem  

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Full Text Available Abstract Background Although plants are the main source of vitamin C in the human diet, we still have a limited understanding of how plants synthesise L-ascorbic acid (AsA and what regulates its concentration in different plant tissues. In particular, the enormous variability in the vitamin C content of storage organs from different plants remains unexplained. Possible sources of AsA in plant storage organs include in situ synthesis and long-distance transport of AsA synthesised in other tissues via the phloem. In this paper we examine a third possibility, that of synthesis within the phloem. Results We provide evidence for the presence of AsA in the phloem sap of a wide range of crop species using aphid stylectomy and histochemical approaches. The activity of almost all the enzymes of the primary AsA biosynthetic pathway were detected in phloem-rich vascular exudates from Cucurbita pepo fruits and AsA biosynthesis was demonstrated in isolated phloem strands from Apium graveolens petioles incubated with a range of precursors (D-glucose, D-mannose, L-galactose and L-galactono-1,4-lactone. Phloem uptake of D-[U-14C]mannose and L-[1-14C]galactose (intermediates of the AsA biosynthetic pathway as well as L-[1-14C]AsA and L-[1-14C]DHA, was observed in Nicotiana benthamiana leaf discs. Conclusions We present the novel finding that active AsA biosynthesis occurs in the phloem. This process must now be considered in the context of mechanisms implicated in whole plant AsA distribution. This work should provoke studies aimed at elucidation of the in vivo substrates for phloem AsA biosynthesis and its contribution to AsA accumulation in plant storage organs.

Haupt Sophie

2003-11-01

180

Probing of ascorbic acid by CdS/dendrimer nanocomposites: a spectroscopic investigation.  

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The gamma irradiation method has provided a route for synthesis of highly water-soluble, good-quality luminescent CdS/dendrimer nanocomposites with amino- or carboxyl-terminated PAMAM dendrimer. An attempt has been made to probe ascorbic acid with the as-synthesized CdS/dendrimer nanocomposites (DNC). Ascorbic acid (AA) is an important biological antioxidant and marker for different diseases in clinical chemistry as well as in quality control in the food industry. Micromolar concentrations of AA significantly quenched the photoluminescence (PL) of both amino (-NH(2)) and carboxylic (-COOH) functionalized semiconductor nanocomposites. The quenching followed a linear Stern-Volmer equation and time-resolved photoluminescence spectroscopy confirmed its static nature. A strong size dependence of the quenching pattern was observed. The binding constants, and the corresponding thermodynamic parameters DeltaG(theta), DeltaH(theta), DeltaS(theta) at different temperatures were calculated. CdS DNC showed selectivity towards ascorbic acid even in the presence of possible interfering molecules, such as uric acid, tartaric acid and citric acid. Nanocomposites-based assay techniques could override the complications involved in multitudes of assay procedures, providing a simple and fast new strategy for the quantification of Ascorbic acid in the range of 16.6 to 100 microM (R=0.998, n=9). The proposed method was applied to the detection of ascorbic acid in Vitamin C tablets with satisfactory results. PMID:20393844

Ghosh, Srabanti; Bhattacharya, S C; Saha, Abhijit

2010-06-01

 
 
 
 
181

Ascorbic acid increases the thrombogenicity of cellular matrices.  

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We have studied the influence of ascorbate on extracellular matrix formation in cultured human endothelial cells, smooth muscle cells and fibroblasts and measured the influence of the changed composition of their isolated extracellular matrices on their affinity for platelets. When endothelial cells were grown for a week in the presence of ascorbate, no influence on proline incorporation in their extracellular matrix was found. In accordance, no influence on platelet adhesion or aggregate formation on these matrices was detected. When smooth muscle cells were cultured in the presence of ascorbate, a strong increase in the amount of collagen types I and III in the extracellular matrix was found. When these matrices were perfused with whole blood, a significant enhanced increase in aggregate formation was observed. No influence was seen on the total coverage of the matrix with platelets. When fibroblasts were grown in the presence of ascorbate, no significant increase in proline incorporation in their matrix was measured. However, an increased adhesion of platelets was seen to the matrices at lower shear rates. We conclude that ascorbate feeding has a significant effect on endogenous deposited matrices of smooth muscle cells and fibroblasts, and that the changed composition had profound effects on platelet interaction with these matrices. PMID:1796403

Hindriks, G A; Sixma, J J; de Groot, P G

1991-10-01

182

Simultaneous detection of ascorbic acid, uric acid and homovanillic acid at copper modified electrode  

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The copper was deposited on glassy carbon (GC) and indium tin oxide (ITO) electrodes by electrochemical method. The copper structures on electrode were characterized by atomic force microscope, X-ray diffractometeric pattern and differential pulse voltammetric studies. Optimal conditions for uniform growth of copper structures on the electrode were established. Voltammetric sensor was fabricated using the copper deposited GC electrode for the simultaneous detection and determination of uric acid (UA) and homovanillic acid (HVA) in the presence of excess concentrations of ascorbic acid (AA). The voltammetric signals due to AA and UA oxidation were well separated with a potential difference of 400 mV and AA did not interfere with the measurement of UA and HVA at the GC/Cu electrode. Linear calibration curves were obtained in the concentration range 1-40 ?M for AA and 20-50 ?M for UA at physiological pH and a detection limit of 10 nM of UA in the presence of 10-fold excess concentrations of AA was achieved. The simultaneous detection of submicromolar concentrations of AA, UA and HVA was achieved at the GC/Cu electrode. The practical utility of the present GC/Cu modified electrode was demonstrated by measuring the AA content in Vitamin C tablet, UA content in human urine and blood serum samples with satisfactory results

183

Simultaneous detection of ascorbic acid, uric acid and homovanillic acid at copper modified electrode  

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The copper was deposited on glassy carbon (GC) and indium tin oxide (ITO) electrodes by electrochemical method. The copper structures on electrode were characterized by atomic force microscope, X-ray diffractometeric pattern and differential pulse voltammetric studies. Optimal conditions for uniform growth of copper structures on the electrode were established. Voltammetric sensor was fabricated using the copper deposited GC electrode for the simultaneous detection and determination of uric acid (UA) and homovanillic acid (HVA) in the presence of excess concentrations of ascorbic acid (AA). The voltammetric signals due to AA and UA oxidation were well separated with a potential difference of 400 mV and AA did not interfere with the measurement of UA and HVA at the GC/Cu electrode. Linear calibration curves were obtained in the concentration range 1-40 {mu}M for AA and 20-50 {mu}M for UA at physiological pH and a detection limit of 10 nM of UA in the presence of 10-fold excess concentrations of AA was achieved. The simultaneous detection of submicromolar concentrations of AA, UA and HVA was achieved at the GC/Cu electrode. The practical utility of the present GC/Cu modified electrode was demonstrated by measuring the AA content in Vitamin C tablet, UA content in human urine and blood serum samples with satisfactory results.

Selvaraju, T. [Centre for Photoelectrochemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021 (India); Ramaraj, R. [Centre for Photoelectrochemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021 (India)]. E-mail: ramarajr@yahoo.com

2007-02-15

184

Intravenous ascorbic acid to prevent and treat cancer-associated sepsis?  

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Full Text Available Abstract The history of ascorbic acid (AA and cancer has been marked with controversy. Clinical studies evaluating AA in cancer outcome continue to the present day. However, the wealth of data suggesting that AA may be highly beneficial in addressing cancer-associated inflammation, particularly progression to systemic inflammatory response syndrome (SIRS and multi organ failure (MOF, has been largely overlooked. Patients with advanced cancer are generally deficient in AA. Once these patients develop septic symptoms, a further decrease in ascorbic acid levels occurs. Given the known role of ascorbate in: a maintaining endothelial and suppression of inflammatory markers; b protection from sepsis in animal models; and c direct antineoplastic effects, we propose the use of ascorbate as an adjuvant to existing modalities in the treatment and prevention of cancer-associated sepsis.

Bogin Vladimir

2011-03-01

185

Protective effect of lipophilic derivatives of ascorbic acid on lipid peroxide-induced endothelial injury.  

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The protective effects of ascorbic acid and its lipophilic derivatives on the cytotoxicity of linoleic acid hydroperoxide (LOOH), a primary product of lipid peroxidation, was investigated in cultured human umbilical vein endothelial cells. When cells were incubated with ascorbic acid for 24 h before treatment with LOOH, ascorbic acid did not protect cells from oxidative damage by LOOH. Its lipophilic derivatives such as 6-O-palmitoyl,6-O-stearoyl, and 2,6-O-dipalmitoyl esters and 2-O-octadecyl ether (CV3611) had an apparent protective effect on the toxicity of LOOH. When cells were incubated in medium containing both antioxidant and LOOH, the protective effect of lipophilic derivatives became weak. An interaction between alpha-tocopherol and ascorbic acid was not observed in this system using endothelial cells. However, in the case where the cells were preincubated with alpha-tocopherol and 6-O-palmitoylascorbic acid, the ascorbic acid derivative had a synergistic effect to alpha-tocopherol in protecting against LOOH-induced damage. These results suggest that lipophilic antioxidants incorporated into cellular membranes are effective protectors against LOOH, whereas lipophobic antioxidants located outside the membrane do not have any protective effect. PMID:8323284

Kaneko, T; Kaji, K; Matsuo, M

1993-07-01

186

Enhanced oxidative stress by L-ascorbic acid within cells challenged by hydrogen peroxide.  

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It has been amply documented that L-ascorbic acid added to the medium of a cell culture increases oxidative damage, and this effect of L-ascorbic acid has been ascribed to the generation of reactive oxygen intermediates in the medium during its auto-oxidation. We have here questioned whether such an effect is exerted inside the cell as well, and if so, what its mechanism is. To assess thiol oxidation in the cell, we manipulated CHO cells so that they could express bacterial alkaline phosphatase in the cytoplasm. Alkaline phosphatase activity, which requires the formation of intramolecular disulfide bridges, was shown to appear when the cells were exposed to H2O2. This H2O2-induced activity increased more than 1.5 fold when L-ascorbic acid had been loaded in the cells by incubation with L-ascorbic acid-2-O-phosphate. Similar enhancing effects were also observed by assessing oxidation of glutathione, formation of protein carbonyls, and generation of reactive oxygen intermediates. Interestingly, the effects by the L-ascorbic acid-2-O-phosphate treatment were totally suppressed by addition of the membrane-permeable chelator deferoxamine to the medium, indicating the involvement of iron ions. Because the apoprotein of conalbumin, which binds iron ions with a high affinity, had no effect and because the same deferoxamine effect was observed with the cells incubated in balanced salt solution with no metal salts added, it was concluded that L-ascorbic acid acts as a pro-oxidant within the cell suffering oxidative stress, and that this effect is elicited through increased redox-cycling of iron in combination with L-ascorbic acid. PMID:16521698

Inai, Yoko; Bi, Wenxiang; Shiraishi, Noriyuki; Nishikimi, Morimitsu

2005-12-01

187

Antioxidant Effects of Aqueous Extract of Sweet Potato and Ascorbic Acid on Paracetamol Induced Damage  

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Full Text Available The antioxidant effects of aqueous extract of sweet potato (Ipomoea batata and ascorbic acid on paracetamol induced damage in liver and kidney were investigated in female rats by monitoring the enzymatic and non-enzymatic antioxidant profiles as well as lipid peroxidation and serum enzymes activities. The rats were given freshly prepared aqueous extract of sweet potato (100 mg kg-1 body weight or ascorbic acid (100 mg kg-1 body weight orally for 4 weeks. These rats were also given paracetamol (4 g kg-1 body weight orally for 2 days at the last week of treatment. Another group of rats were either given extract (100 mg kg-1 body weight. daily, orally, for 4 weeks or ascorbic acid (100 mg kg-1 body weight. daily, orally, for 4 weeks or paracetamol (4 g kg-1 body weight for 2 days or distilled water. The results show that the level of lipid peroxides in the liver and kidney and serum enzymes GOT and GPT activities were significantly decreased in extract and ascorbic acid pretreated rats when compared to control (p<0.05. Paracetamol however significantly increase the level of these parameters when compared to control. Liver and kidney Superoxide Dismutase (SOD and Catalase activities significantly increase in extract and ascorbic acid pretreated rats compared to control. Paracetamol significantly reduced the activities of these enzymes in liver but the reduction in SOD activity was not significant in the kidney when compared to control. There were significant increase in reduced Glutathione (GSH in both organs in ascorbic acid pretreated rat but the increase were not significant in extract pretreated rats. Paracetamol significantly decrease GSH level in the liver when compared to control. The study revealed that sweet potato extract and ascorbic acid have a potential to prevent oxidative damage induced by acute dose of paracetamol in both the liver and the kidney.

A.O. Lawal

2006-01-01

188

Effect of Storage Time on Ascorbic Acid Content of Some Selected `Made in Nigeria` Fruit Preserves  

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Full Text Available The vitamin C content of many "Made in Nigeria" fruit products is not known for sure, since Nutrition Labeling is usually absent. Furthermore the change in the concentration with increasing shelf-life is not certain. Ascorbic acid (vitamin C content of sixteen different fruit preserves made in Nigeria was assessed, on the day of production and after different lengths of storage time ranging from 3 to 8 months. Six fruit juices, six fruit squashes and four marmalades/jams were analyzed for ascorbic acid contents using the 2,6 dichlorophenol indophenol visual titration method. Ascorbic acid content varied with the type of fruit preserve, grapefruit juice having the highest (42.0mg/100g, while pineapple juice had the lowest (10.3mg/100g on the first day of manufacture/production. Other juices had values ranging from 20.0mg/100g to 41.5mg/100g sample. There was minimal loss in ascorbic acid content with time. Fruit squashes generally had higher ascorbic acid content than the juices. Mango had the highest (62.0mg/100g, while pineapple squash had the lowest (18.1mg/100g on the first day of production/manufacture. The percentage loss in ascorbic acid content of squashes was lower than that found in similar fruit juices. Other fruit preserves also had values ranging from 13.1mg/100g to 50mg/100g. Ascorbic acid loss was more than 10% in marmalades and jams after storage for 12 months at ambient room temperature. While processing of fruits reduce post-harvest loss and provides nutrients from these fruits, it will be beneficial to apply nutrition labels to the containers and also print `best before` date conspicuously. Nutrition education is necessary to increase market demand and monitoring to ensure quality. The effect of ambient conditions should be considered in manufacture procedures.

SANUSI Rasaki A.

2008-01-01

189

Use of Experimental Design for Calibration and Validation of Ascorbic Acid and Citric Acid Mixtures  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish El objetivo general de este trabajo ha sido el desarrollo y aplicación de metodologías analíticas basadas en la combinación de medidas espectroscópicas de UV con métodos quimiométricos de diseño de experimentos para establecer la matriz de calibración y posterior análisis de los resultados obtenidos [...] . Los analitos seleccionados para este estudio han sido el ácido cítrico y el ácido tartárico. El ácido cítrico es un ácido orgánico tricarboxílico presente en la mayoría de las frutas, principalmente en cítricos como el limón y la naranja. El ácido ascórbico (vitamina C) es un ácido orgánico con propiedades antioxidantes, importante para el sistema inmunológico y para prevenir enfermedades. Abstract in english The general objective of present work has been the development and application of analytical methodologies based on the combination of UV spectra with chemometrics methods of experimental design for establishing the matrix of calibration and later analysis of the obtained results. The analytes selec [...] ted for this study have been citric acid and ascorbic acid. The citric acid is a tri-carboxylic organic acid that is present in most of the fruits, mainly in citrus like the lemon and the orange. Ascorbic acid (vitamin C) is an organic acid with antioxidant properties; their importance for the human immune system and for the prevention of various diseases is a matter of common knowledge.

Fuensanta, Sánchez Rojas; Catalina, Bosch Ojeda; Antonio Jesús, Ruiz Sánchez; María, Espinosa Bosch.

2008-12-01

190

A study of the peroxidation of fatty acid micelles promoted by ionizing radiation, hydrogen peroxide and ascorbate  

International Nuclear Information System (INIS)

The kinetics of peroxidation of fatty acid micelles promoted by ionizing radiation, hydrogen peroxide and ascorbate were compared. At the dose-rate range of ionizing radiation studied, the higher the dose-rate, the greater the total dose required to produce the same effect. With ascorbate, the rate of lipid peroxidation was dependent on the concentration of the promoter only up to 1 x 10-4M, beyond which a decreasing rate of peroxidation induction was observed. Higher concentration of ascorbate also suppressed the promoting effect of ionizing radiation. Formate, a hydroxyl radical scavenger, inhibited the peroxidation process promoted by these three agents. Caesium was found to be slightly inhibitory. EDTA and deoxycholate were also inhibitory, which may be attributed to iron-chelating and micelle-disrupting capacity, respectively. Addition of iron (Fe2+ or Fe3+) to EDTA-chelated fatty acid micelles re-initiated the peroxidation process. The ease of fatty acid oxidation at pH 7.5 was arochidonic (20:4)>linolenic (18:3)>linoleic (18:2). This order was reversed at pH 11.5. Similarities in the kinetics of peroxidation obtained suggest that certain biological sequelae encountered in cells treated with these seemingly dissimilar agents might arise through some common mechanism(s). (author)

191

Effect of ascorbic acid on cadmium toxicity in the young coturnix  

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This study was designed to evaluate the effects of supplements of individual dietary components in altering the toxicity of dietary cadmium. Day-old coturnix (Japanese quail) were fed 75 mg Cd/kg of an adequate purified diet for 2- or 4-week periods. Cadmium produced moderate growth retardation, severe anemia, decreased ash content of the tibia, and deviations from the normal concentrations of zinc, iron, cadmium, copper, and calcium in one or more of the cells or tissues assayed (erythrocyte, liver, kidney, and tibia). Dietary supplements of zinc, iron(III), copper, and L-cysteine-HCl and injected ascorbic acid produced slight to moderate protection against cadmium-induced anemia, whereas iron(II), ascorbic acid, and D-isoascorbic acid had marked effects in preventing the anemia, growth retardation, poor bone mineralization, and perturbations in elemental concentrations of tissues. Chromium, cobalt, selenium, nickel, molybdenum, and pteroylglutamic acid had no effects. Cadmium did not affect the total ascorbate content of the liver. Removal of dietary ethoxyquin did not affect the toxicity of cadmium or the protective effects of ascorbic acid. Initiation of ascorbic acid feeding at 2 weeks was beneficial to birds fed cadmium throughout the 4-week experiment. Under the conditions of these experiments cadmium produced a functional iron deficiency and less clear-cut affects on zinc function. It appears that a primary effect of cadmium was to prevent absorption of dietary iron. 33 references, 6 tables.

Fox, M.R.S.; Fry, B.E. Jr.; Harland, B.F.; Schertel, M.E.; Weeks, C.E.

1971-01-01

192

Determination of L-Ascorbic Acid in Pharmaceutical Preparations Using Direct Ultraviolet Spectrophotometry  

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Full Text Available A new, selective and accurate direct ultraviolet spectrophotometric method was developed for the determination of L-ascorbic acid in pharmaceuticals. The oxidation of L-ascorbic acid by iodate in an acidic medium was used as a means of correcting for background absorption. The molar absorptivity of the proposed method was found to be 8.71x103 dm3 mol-1 cm-1 at 250 nm. Beer’s law was obeyed in the concentration range of 0.46 – 16.00 ?g cm-3 for L-ascorbic acid. The relative standard deviation was 0.67 % for a concentration of 8.00 ?g cm-3 of ascorbic acid (n = 7. The ingredients commonly found in vitamin C and multivitamin products did not interfere. The proposed procedure was successfully applied to assays of L-ascorbic acid in pharmaceutical preparations. The results obtained with the proposed method showed good agreement with those given by the titrimetric method using iodine.

Mirsad Salki?

2009-12-01

193

The Effect of Ascorbic Acid Treatment on Viability and Vigor Maize (Zea mays L.) Seedling under Drought Stress  

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This study was conducted in the laboratory and the field to examine the effects of ascorbic acid treatment on germination and seedling growth under drought stress. The laboratory works consisted of two experiments and were designed to determine the critical osmotic potential of maize and to determine the optimum ascorbic acid concentration. The field study was designed to examine the effects of soaking seed in ascorbic acid on seedling growth under drought stress. Drought condition was simula...

HAMIDAH HAMAMA; ENDANG MURNIATI

2010-01-01

194

Comparison between radioimmunoanalysis and Mancini methods for a case of ascorbic acid radioprotection on rats contaminated with tritiated water  

International Nuclear Information System (INIS)

The recovery of humoral immune response has been comparatively studied by a radioimmunoanalysis (RIA) method and by Mancini single immuno radial diffusion method in an experiment consisting in chronic contamination with low doses of tritiated water (HTO) and oral administration of high doses of ascorbic acid on rats as radioprotector. The radioprotective effect of ascorbic acid was found to be dependent both on the radiation dose and the amount of ascorbic acid administered. (author). 11 refs., 1 tab

195

The Effect of Oral Ascorbic Acid Pretreatment on Feeding Changes Following Injection in Nucleus Accumbens Shell in Adult Male Rats  

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Background: Ascorbic acid (AA) is not synthesized in the brain but it is actively transported through blood-brain barrier by SVCT2 cotransporter and it is stored in high concentrations with heterogeneous distribution in areas such as nucleus accumbens shell (AcbSh) in the mammalian brain. Previous studies have shown that Ascorbic acid injection into AcbSh decreases feeding; therefore, in the present study we evaluated the effects of oral Ascorbic acid pretreatment on changes in feeding upon i...

Badreh F; Abbasnejad M; Esmaeili Mahani S; Salari S

2012-01-01

196

Ascorbic acid treatment reduces the radiation-induced delay in the skin excision wound of Swiss mice  

International Nuclear Information System (INIS)

Effect of ascorbic acid was studied on the radiation induced changes in wound contraction, collagen synthesis. Wound histology, glutathione, glutathione peroxidase, superoxide dismutase and lipid peroxidation in mice exposed to 10, 16, and 20 Gy of fractionated gamma radiation. The animals were administered daily with double distilled water or ascorbic acid before exposure to 2 Gy/da fractionated irradiation. Ascorbic acid pretreatment resulted in a significant elevation in the activities of both the enzymes and glutathione in the irradiated mouse skin

197

The Effect of ascorbic acid injection into lateral ventricle on spatial learning and memory on adult male rats  

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Introduction: Ascorbic acid (AA) acts as an antioxidant in the Central nervous system (CNS) of the mammalians. It is released from the some nerve ending together with neurotransmitters. The results have shown that Ascorbic acid could affect learning as well as memory. In this study, we examined the effect of ICV injection of ascorbic acid on learning and memory by Morris water maze. Method: In the present study, 42 adult male rats weighing 250-300 g were used. then cannula implanted bilateral...

mehdi abbasnejad; Sima Nasri; Habib Nazem; Mehri Bahaaddini

2008-01-01

198

Ascorbic acid protects the newborn rat brain from hypoxic-ischemia.  

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Ascorbic acid (AA) is a potent antioxidant, and its neuroprotective effect has not been established yet. Using the Rice-Vannucci model, we examined the effect of AA on hypoxic-ischemic (HI) injury in the immature rat brain. Under isoflurane anesthesia, 7-day-old rat pups received 750 mg/kg of AA by intraperitoneal injection just before hypoxic exposure; 8% oxygen for 90 min. Vehicle controls received an equal volume of saline. AA decreased a macroscopic brain injury score at 48 and 168 h post-HI compared with vehicle controls (48 h post-HI, AA 1.38+/-0.45 vs. controls 2.94+/-0.24, pcaudate putamen, thalamus and hippocampus, and also seemed to reduce the number of TUNEL-positive cells. Western blot analysis showed that AA significantly suppressed 150/145 kDa subunits of alpha-fodrin breakdown products (FBDP) in cortex, striatum, thalamus and hippocampus at 24 and 48 h post-HI, and also 120 kDa subunit of FBDP in all examined regions except for thalamus, which indicated that AA injection inhibited both calpain and caspase-3 activation. Western blot analysis of nitrotyrosine failed to show inhibition of free radical production by AA, however, our results show that AA inhibits both necrotic and apoptotic cell death and that AA is neuroprotective after HI in immature rat brain. PMID:18682317

Miura, Shinobu; Ishida-Nakajima, Wako; Ishida, Akira; Kawamura, Masanari; Ohmura, Akiko; Oguma, Rena; Sato, Yoko; Takahashi, Tsutomu

2009-04-01

199

Investigations on protonation constants and thermodynamic parameters of ascorbic acid, used in decontamination of reactor coolant channels  

International Nuclear Information System (INIS)

The protonation equilibria for ascorbic acid in ionic strength of 1.0 mol/dm3 NaClO4 medium have been studied using pH-potentiometrically. The protonation constants of ascorbic acid and the thermodynamic functions (?G0, ?H0, and ?S0) for the successive and overall protonation processes of ascorbic acid have been derived at three different temperatures. A detailed thermodynamic analysis of the effects of temperature and ascorbic acid concentration influencing the protonation processes is presented and discussed to determine the factors which control these processes. (author)

200

The comparison of techniques and methods for L-ascorbic acid determination in the fruits  

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Full Text Available Vitamin C is an essential vitamin for human nutrition; with the L-ascorbic acid (AA being the active form of vitamin C. Hence, determination of the L-ascorbic acid in the natural and processed foods is very important. In the past, plenty of methods based on the reversible redox reaction of AA oxidation/DHA reduction were developed. Because of L-ascorbic acid instability in aqueous solutions, it is useful to analyze various types of extraction. The aim of this study is to compare three different methods and three different extractants for the L-ascorbic acid determination. Fruits (kiwi, lemon, orange, and grapefruit were purchased from a local market. The L-ascorbic acid in these four samples was determined by the three different methods: the AOAC, the HPLC method with three different types of extractions, and the colorimetric method using ascorbate-oxidase. For the HPLC measurements, one part of the fruits was extracted with distilled water, the second with potassium hydrogen phosphate, and the third with 3% meta-phosphoric acid (MPA in 8% acetic acid. The HPLC measurements of each sample were repeated three times, the AOAC titration was repeated five times, and in the calorimetric method three measurements were performed. The results were statistically evaluated related to sample basis. Statistical analysis shows that there is a significant difference between the results for all three methods of extraction for all samples, except for the grapefruit sample where no significant difference was observed between the results obtained after the buffer extraction (E2 and the metaphosphoric acid in acetic acid extraction (E3. Discriminative analysis for the HPLC determinations proves that there is a clear difference and defined border between the samples in relation to the methods of extraction during the HPLC determination.

Cvetkovi? Biljana R.

2012-01-01

 
 
 
 
201

An Urinary Excretion Profile of 500 mg Ascorbic Acid in Healthy Adults  

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Full Text Available High doses of ascorbic acid have been commercially available as adjuvant. However, the pharmacological importance of this supplement is yet questionable. The aim of this study is to investigate the 24 hours excretion profile of ascorbic acid after oral administration of 500 mg single dose in healthy volunteer. The urine samples were collected at 2, 4, 6, 8, and 24 hours after administration. The samples were extracted with trichloroacetic acid, followed by colorimetric measurement. The excretion profile showed a curve with concentrations of 14.4, 15.2, 15.6, 14.9, and 14.2% at 2, 4, 6, 8, and 24 hours, respectively. This suggests that 74.3% of ascorbic acid to be excreted via urine as an excessive amount and a high adjuvant dosage should be reconsidered.

Mutakin

2012-06-01

202

Effect of ascorbic acid and green tea on endogenous formation of N-nitrosodimethylamine and N-nitrosopiperidine in humans.  

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Many constituents present in the human diet may inhibit endogenous formation of N-nitroso compounds (NOC). Studies with human volunteers showed inhibiting effects of intake of ascorbic acid and green tea consumption on nitrosation using the N-nitrosoproline test. The aim of the present study was to evaluate the effects of ascorbic acid and green tea on urinary excretion of carcinogenic N-nitrosodimethylamine (NDMA) and N-nitrosopiperidine (NPIP) in humans. Twenty-five healthy female volunteers consumed a fish meal rich in amines as nitrosatable precursors in combination with intake of nitrate-containing drinking water at the Acceptable Daily Intake level during 7 consecutive days. During 1 week before and after nitrate intake a diet low in nitrate was consumed. Using the same protocol, the effect of two different doses of ascorbic acid (250 mg and 1 g/day) and two different doses of green tea (2 g and 4 g/day) on formation of NDMA and NPIP was studied. Mean nitrate excretion in urine significantly increased from control (76+/-24) to 167+/-25 mg/24 h. Intake of nitrate and fish resulted in a significant increase in mean urinary excretion of NDMA compared with the control weeks: 871+/-430 and 640+/-277 ng/24 h during days 1-3 and 4-7, respectively, compared with 385+/-196 ng/24 h (p<0.0002). Excretion of NPIP in urine was not related to nitrate intake and composition of the diet. Intake of 250 mg and 1 g of ascorbic acid per day resulted in a significant decrease in urinary NDMA excretion during days 4-7 (p=0.0001), but not during days 1-3. Also, consumption of four cups of green tea per day (2 g) significantly decreased excretion of NDMA during days 4-7 (p=0.0035), but not during days 1-3. Surprisingly, consumption of eight cups of green tea per day (4 g) significantly increased NDMA excretion during days 4-7 (p=0.0001), again not during days 1-3. This increase is probably a result of catalytic effects of tea polyphenols on nitrosation, or of another, yet unknown, mechanism. These results suggest that intake of ascorbic acid and moderate consumption of green tea can reduce endogenous NDMA formation. PMID:10518007

Vermeer, I T; Moonen, E J; Dallinga, J W; Kleinjans, J C; van Maanen, J M

1999-07-16

203

Electrochemical oxidation of ascorbic acid mediated by carbon nano tubes/ Li+/ carbon paste modified solid electrode  

International Nuclear Information System (INIS)

Multi-walled carbon nano tube (MWCNT) was used to modify BPPG electrode because of its unique structure and extraordinary properties. MWCNT modified electrode exhibited obvious enhancing and electro catalyzing effects to the oxidation of ascorbic acid using cyclic voltammetry technique. MWCNT was bonded on BPPG electrode surface using carbon paste with ratio of 30 % (w/ W) carbon paste (binder): 70 % (w/ w) MWCNT. This method of modification has lowered the capacitance background current and enabled lower detection limit of ascorbic acid concentration. The electrical conductivity property of MWCNT modified electrode was further improved with the intercalation with lithium ion and resulted in current enhancement of 2 times on the oxidation current of ascorbic acid. Parameters of pH and temperature showed significant relation to the sensitivity of MWCNT modified electrode. Under the optimized parameters, the calibration curve constructed was linear up from 50 ?M to 5 mM with sensitivity of 34.5 mA M-1. The practical application of MWCNT modified electrode was demonstrated with Vitamin C pill and orange juice. Good reproducibility and recovery of ascorbic acid concentration showed the feasibility of MWCNT modified electrode to be used in the detection of ascorbic acid in aqueous solution. This also proposed MWCNT modified BPPG electrode possessed advantages such as low detection limit, high stability, low cost and simplicity in fabrication. (author)

204

The decay of ascorbic acid in a model wine system at low oxygen concentration.  

Science.gov (United States)

The present study investigated the impact of temperature on the degradation of ascorbic acid in low oxygen conditions in a model white wine. The concentrations of ascorbic acid, furfural, sulfur dioxide and phenolic-type products were monitored in a model white wine stored under non-oxidative conditions at 45.0, 36.5 and 24.0 °C for up to 693 days. The concentrations of both ascorbic acid and sulfur dioxide decreased over the analysis period while furfural and other colourless phenolic products increased in concentration, despite the presence of residual sulfur dioxide. The decay of ascorbic acid in the low oxygen conditions followed first-order kinetics and the rate constants were determined to be (3.5±0.2)×10(-8), (1.02±0.07)×10(-8), and (0.184±0.009)×10(-8) s(-1) for 45.0, 36.5 and 24.0 °C (n=5, standard error), respectively, and the activation energy was 110±3 kJ/mol (n=3, standard error). Importantly, these data allow more accurate prediction of the temperature-induced loss of ascorbic acid in low oxygen conditions during transport or storage of wine. PMID:23871070

Wallington, Nadja; Clark, Andrew C; Prenzler, Paul D; Barril, Celia; Scollary, Geoffrey R

2013-12-01

205

Arsenic-induced toxicity and the protective role of ascorbic acid in mouse testis  

International Nuclear Information System (INIS)

Oxidative stress has been suggested to be a major cause of male reproductive failure. Here, we investigated whether arsenic, which impairs male reproductive functions in rodent models, acts by inducing oxidative stress. Male 8-week-old ICR mice were given drinking water containing 20 or 40 mg/l sodium arsenite with or without 0.75 or 1.5 g/l of the antioxidant ascorbic acid for 5 weeks. The arsenic-treated mice showed decreased epididymidal sperm counts and testicular weights compared to untreated mice. These effects were reversed in mice that were co-treated with ascorbic acid. Similarly, arsenic treatment lowered the activities of testicular 3?-hydroxysteroid dehydrogenase (HSD) and 17?-HSD, which play important roles in steroidogenesis, and this was reversed by co-treatment with ascorbic acid. The testicles of arsenic-treated mice had decreased glutathione (GSH) levels (which correlate inversely with the degree of cellular oxidative stress) and elevated levels of protein carbonyl (a marker of oxidative damage to tissue proteins). Ascorbic acid co-treatment reversed both of these effects. Thus, ascorbic acid blocks both the adverse effects of arsenic on male reproductive functions and the arsenic-induced testicular oxidative changes. These observations support the notion that arsenic impairs male reproductive function by inducing oxidative stress

206

Effect of large-dose ascorbic acid on the two-drop clinitest determination.  

Science.gov (United States)

A study was conducted to determine if high doses of ascorbic acid would affect the two-drop Clinitest determination for glucosuria in normal individuals. Numerous secondary literature sources indicate that large doses of ascorbic acid may cause a false positive Clinitest result. Three-gram and nine-gram doses of ascorbic acid following two dosing schedules (once daily and three times daily) were taken by nine normal individuals to determine if the renal excretion of large enough quantities of ascorbic acid or its metabolites would produce false positive results with the two-drop Clinitest procedure. Each dose was given for seven days in each schedule. There were only two (0.27%) trace positive Clinitest determinations reported out of 748 Clinitest determinations. High doses of ascorbic acid in normal individuals do not appear to affect the two-drop Clinitest determination for urinary glucose. The study indicates a need to be cautious about secondary literature references on drug-laboratory test interferences. PMID:596386

Smith, D; Young, W W

1977-12-01

207

Ascorbic acid protects against restraint stress-induced memory deficits in wistar rats  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english OBJECTIVE: Chronic stress has been shown to cause oxidative damage in the central nervous system. Although stress-induced impairments in learning and memory have been studied extensively, very few studies have investigated possible ways to prevent their ill effects. The present work was designed to [...] study the protective effects of ascorbic acid in memory loss induced by chronic restraint stress. METHODS: Adult male Wistar rats were designated into the following groups: (i) Normal control, (ii) Ascorbic acid treatment, (iii) Vehicle control, (iv) Restraint stress, (v) Restraint stress + vehicle, and (vi) Restraint stress + ascorbic acid treatment. At the end of 21 days, animals of all groups were subjected to memory tests using Morris water maze and passive avoidance apparatus. Then, the results obtained were compared between the experimental groups. RESULTS: Rats exposed to restraint stress alone and those pretreated with vehicle solution before restrained stress showed deficits in learning and impaired memory retention in the memory tests when compared to animals in other experimental groups. Animals pretreated with ascorbic acid before restraining showed significant improvement in memory retention in the same memory tests. CONCLUSIONS: Results of this study suggest the possibility of using ascorbic acid as a dietary supplement to prevent stress-induced memory impairments.

Raju Suresh, Kumar; Sareesh Naduvil, Narayanan; Satheesha, Nayak.

1211-12-01

208

Self-powered biosensor for ascorbic acid with a Prussian blue electrochromic display.  

Science.gov (United States)

We report on the development of a nanocarbon based anode for sensing of ascorbic acid (AA). The oxidation of AA on this anode occurs at a quite low overpotential which enables the anode to be connected to a biocathode to form an ascorbic acid/O2 biofuel cell that functions as a self-powered biosensor. In conjunction with a Prussian blue electrochromic display the anode can also work as a truly self-powered sensor. The oxidation of ascorbic acid at the anode leads to a reduction of the Prussian blue in the display. The reduced form of Prussian blue, called Prussian white, is transparent. The rate of change from blue to colourless is dependent on the concentration of ascorbic acid. The display can easily be regenerated by connecting it to the biocathode which returns the Prussian blue to its oxidized form. In this way we have created the first self-powered electrochromic sensor that gives quantitative information about the analyte concentration. This is demonstrated by measuring the concentration of ascorbic acid in orange juice. The reported quantitative read-out electrochromic display can serve as a template for the creation of cheap, miniturizable sensors for other relevant analytes. PMID:24321882

Zloczewska, Adrianna; Celebanska, Anna; Szot, Katarzyna; Tomaszewska, Dorota; Opallo, Marcin; Jönsson-Niedziolka, Martin

2014-04-15

209

Ascorbic acid protects against restraint stress-induced memory deficits in wistar rats  

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Full Text Available OBJECTIVE: Chronic stress has been shown to cause oxidative damage in the central nervous system. Although stress-induced impairments in learning and memory have been studied extensively, very few studies have investigated possible ways to prevent their ill effects. The present work was designed to study the protective effects of ascorbic acid in memory loss induced by chronic restraint stress. METHODS: Adult male Wistar rats were designated into the following groups: (i Normal control, (ii Ascorbic acid treatment, (iii Vehicle control, (iv Restraint stress, (v Restraint stress + vehicle, and (vi Restraint stress + ascorbic acid treatment. At the end of 21 days, animals of all groups were subjected to memory tests using Morris water maze and passive avoidance apparatus. Then, the results obtained were compared between the experimental groups. RESULTS: Rats exposed to restraint stress alone and those pretreated with vehicle solution before restrained stress showed deficits in learning and impaired memory retention in the memory tests when compared to animals in other experimental groups. Animals pretreated with ascorbic acid before restraining showed significant improvement in memory retention in the same memory tests. CONCLUSIONS: Results of this study suggest the possibility of using ascorbic acid as a dietary supplement to prevent stress-induced memory impairments.

Raju Suresh Kumar

2009-01-01

210

Luminescence quenching of porous silicon nanoparticles in presence of ascorbic acid  

Energy Technology Data Exchange (ETDEWEB)

In this work, the effect of ascorbic acid on luminescence of porous silicon nanoparticles is studied. Porous nanoparticles with a multi-sized distribution are produced from a porous silicon free standing film and filtered through a 450 nm membrane. The highly luminescent and water-soluble nanoparticles are dispersed in deionized water. The stability of photoluminescence signal and the dimensions of porous silicon nanoparticles are characterized before adding ascorbic acid into the porous nanoparticles solution. The increasing of photoluminescence, before stabilization, has been correlated to oxidation of nanoparticles in water, evaluated by the technique of Attenuated Total Reflection. Once the nanoparticle photoluminescence signal is stabilized, ascorbic acid is loaded into the solution and its presence and real absorption onto the porous silicon nanoparticles are evaluated from their emission quenching. The quenching of photoluminescence is studied with different concentrations of ascorbic acid by Stern-Volmer plot for confirming the quenching law. This study shows that luminescence quenching of porous nanoparticles could be used for determining the presence of ascorbic acid in a solution. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

La Ferrara, Vera; Fiorentino, Giuseppe; Rametta, Gabriella; Di Francia, Girolamo [ENEA Research Centre, Portici (Italy)

2012-04-15

211

Oxidation in fish oil enriched mayonnaise : Ascorbic acid and low pH increase oxidative deterioration  

DEFF Research Database (Denmark)

The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil- water interface into the aqueous phase at all pH levels, but this effect of ascorbic acid was strongest at low pH (pH 3.8- 4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted oxidation. It is proposed that iron bridges between the egg yolk proteins low-density lipoproteins, lipovitellin, and phosvitin at the oil-water interface are broken at low pH values, whereby iron ions become accessible as oxidation initiators. In the presence of ascorbic acid, oxidation is further enhanced due to the reduction of Fe3+ to Fe2+ that rapidly catalyzes lipid oxidation via lipid hydroperoxide decomposition at the oil-water interface in mayonnaise

Jacobsen, Charlotte; Timm Heinrich, Maike

2001-01-01

212

Protective Effect Of Ascorbic Acid On Cisplatin Genotoxicity In Male Mice Bone Marrow Cells  

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Full Text Available Cisplatin (cis-diamminedichloroplatinum II is an effective antitumor agent with a wide spectrum of activity against varies solid tumors, but it has serious side effects on nontumour cells. Cisplatin produces intra- and interstrand DNA cross-linking effects and chromosomal aberrations in mammalian cells. Vitamin C (ascorbic acid is an antioxidant that can scavenge free radicals and protect cellular macromolecules, including DNA, from oxidative damage induced by different agents. Pretreatment administration of ascorbic acid on cisplatin induced chromosome aberrations has been determined in bone marrow cells of Swiss albino mice. Results showed that cisplatin (7.5 & 10mg/kg bwIP injection to male mice induced significant increase in the frequencies of chromosomal aberrations. The results of pre-treatment with ascorbic acid (66mg/kg bw showed a significant decrease in the number of chromosomal aberrations induced with cisplatin tested doses. Ascorbic acid did not exhibit any clastogenic effect in male mice bone marrow cells. We concluded that ascorbic acid has a protective role against the genotoxicity induced by antitumor drug cisplatin.

Nada, H.A. Al- Twaty

2005-03-01

213

Electrocatalysis and Determination of Ascorbic Acid Through Graphite Paste Electrode Modified With Iron Nitroprusside  

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Full Text Available Iron nitroprusside, Fe(IINP was incorporated into a carbon paste electrode and the electrochemical studies were performed by cyclic voltammetry. The cyclic voltammogram of the modified electrode, Fe(IINP showed two redox couples ( E½ox1 = 0.24 and (E½ox2 = 0.85 V vs. SCE attributed to Fe(II/Fe(III and Fe(II(CN5NO / Fe(III(CN5NO, respectively. The redox couple at (E½ox1 = 0.24 V presents an electrocatalytic response for ascorbic acid. The modified paste electrode exhibits a decrease of 180 mV in the ascorbic acid oxidation. The modified graphite paste electrode gives a linear range from 1.0 × 10-3 to 2.6 × 10-2 mol L-1 of ascorbic acid with a detection limit of 1.4 × 10-3 (±1.2% mol L-1 (n =3. The electrocatalytic oxidation of ascorbic acid compounds by the mediator has been used for the determination of ascorbic acid in a commercially pharmaceutical available product.

Devaney R. do Carmo

2004-01-01

214

Preparation and Characterization of Poly(D,L-Lactide-co-Glycolide Nanoparticles Containing Ascorbic Acid  

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Full Text Available This paper is covering new, simplistic method of obtaining the system for controlled delivery of the ascorbic acid. Copolymer poly (D,L-lactide-co-glycolide (DLPLG nanoparticles are produced using physical method with solvent/nonsolvent systems where obtained solutions were centrifuged. The encapsulation of the ascorbic acid in the polymer matrix is performed by homogenization of water and organic phases. Particles of the DLPLG with the different content of ascorbic acid have different morphological characteristics, that is, variable degree of uniformity, agglomeration, sizes, and spherical shaping. Mean sizes of nanoparticles, which contain DLPLG/ascorbic acid in the ratio 85/150%, were between 130 to 200 nm depending on which stereological parameters are considered (maximal diameters Dmax, feret X, or feret Y. By introducing up to 15% of ascorbic acid, the spherical shape, size, and uniformity of DLPLG particles are preserved. The samples were characterized by infrared spectroscopy, scanning electron microscopy, stereological analysis, and ultraviolet spectroscopy.

Magdalena M. Stevanovi?

2007-09-01

215

Effect of Ascorbic Acid and Cysteine Hydrochloride on Growth of Bifidobacterium bifidum  

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Full Text Available The effects of ascorbic acid and L-Cysteine Hydrochloride (Cys-HCl on growth of Bifidobacterium bifidum BB01 and BB03 were studied by using MRS broth as the control, the concentrations of ascorbic acid and Cys-HCl were both of 0.4, 0.6, 0.8, 1.0 and 1.2g/L. The result showed as follows: ascorbic acid 0.8g/L or Cys-HCl 0.6g/L on growth of B. bifidum BB01 and ascorbic acid 0.4g/L and Cys-HCl 0.4g/L on growth of B. bifidum BB03 had significant influence (p<0.05, respectively. The OD600 of B. bifidum BB01 and B. bifidum BB03 reached 1.32, 1.32, 1.347 and 1.296 at optimal concentration of ascorbic acid and Cys-HCl mentioned above, while the control only reached 1.121 and 1.213 respectively.

Guowei Shu

2013-06-01

216

Ascorbic acid reduced mutagenicity at the HPRT locus in CHO cells against thermal neutron radiation  

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We investigated the biological effects of the long-lived radicals induced following neutron irradiation. It has been reported that radiation-induced long-lived radicals were scavenged by post-irradiation treatment of ascorbic acid (Koyama, 1998). We studied the effects of ascorbic acid acting as a long-lived radical scavenger on cell killing and mutagenicity in Chinese hamster ovary cells against thermal neutrons produced at the Kyoto University Research reactor. Ascorbic acid was added to cells 30 min after neutron irradiation and removed 150 min after irradiation. The biological end point of cell survival was measured by colony formation assay. The mutagenicity was measured by the mutant frequency in the HPRT locus. The post-irradiation treatment of ascorbic acid did not alter the cell killing effect of neutron radiation. However, the mutagenicity was decreased, especially when the cells were irradiated with boron. Our results suggested that ascorbic acid scavenged long-lived radicals effectively and caused apparent protective effects against mutagenicity of boron neutron capture therapy.

Kinashi, Yuko E-mail: kinasi@rri.kyoto-u.ac.jp; Sakurai, Yoshinori; Masunaga, Shinichiro; Suzuki, Minoru; Nagata, Kenji; Ono, Koji

2004-11-01

217

Kinetics of Ascorbic Acid Degradation in Un-Pasteurized Iranian Lemon Juice During Regular Storage Conditions  

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The aim of this research was to determine shelf life stability of un-pasteurized lemon juice filled in clear or dark green glass bottles. Presence of light, time and temperature affect the ascorbic acid retention in citrus juices. Bottles were stored at room temperature (27 ± 3 °C) and in the refrigerator (3 ± 1 °C). Total soluble solids, total titrable acidity and pH value were measured every three weeks and analysis was carried out on ascorbic acid content by means of titration me...

Abbasi; Niakousari, M.

2008-01-01

218

Effect of Ascorbic Acid and Acetylsalicylic Acid Supplementation on Performance of Broiler Chicks Exposed to Heat Stress  

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Full Text Available A total of 100, day-old broiler chickens were randomly divided into 5 groups and kept under elevated temperature (34-36oC to see the effect of ascorbic acid and acetylsalicylic acid (Sb-Asper-C, a commercial product on the feed conversion ratio (FCR, immune status and ratio of weight of bursa, thymus and spleen to body weight. Heat stress increased the FCR but decreased the immune response and ratio of bursa, thymus and spleen to body weight of the birds. Ascorbic acid and acetylsalicylic acid supplementation during heat stress had beneficial effects on FCR, immune status and ratio of weight of bursa, thymus and spleen to body weight of the birds. Grossly, bursa thymus and spleen of heat stressed birds were atrophied but ascorbic acid and acetylsalicylic acid supplemented birds were not atrophied, No specific histopathological changes were observed in all groups.

Shamoon Naseem

2005-01-01

219

EFFECTS OF ASCORBIC ACID AND ACETYLSALICYLIC ACID SUPPLEMENTATION ON THE PERFORMANCE OF BROILER CHICKS EXPOSED TO HEAT STRESS  

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Full Text Available A total of 100, day-old broiler chicks were randomly divided into 5 equal groups and kept under elevated temperature (93-97oF to see the effect of ascorbic acid and acetylsalicylic acid on the feed conversion ratio (FCR, immune status and ratio of weight of bursa, thymus and spleen to body weight. Heat stress increased the FCR but decreased the immune response and ratio of bursa, thymus and spleen to body weight of the birds. Ascorbic acid and acetylsalicylic acid supplementation during heat stress had beneficial effects on FCR, immune status and ratio of bursa, thymus and spleen to body weight. Grossly, bursa, thymus and spleen of heat stressed birds were atrophied but in ascorbic acid and acetylsalicylic acid supplemented birds these organs were not atrophied. No specific histopathological changes were observed in all groups.

B. Anwar, S. A. Khan, A. Aslam, A. Maqbool1 and K. A. Khan

2004-07-01

220

Reactions of halogenated organic peroxyl radicals with various purine derivatives and ascorbic acid in quaternary microemulsion  

International Nuclear Information System (INIS)

Absolute rate constants for the one electron oxidation of guanine, xanthine, hypoxanthine, uric acid and ascorbic acid in quaternary microemulsion have been determined using the technique of pulse radiolysis. The rate constants for the radical CBr3O2. are slightly higher than those for CCl3O2. (author)

 
 
 
 
221

The Use of Ascorbate as an Oxidation Inhibitor in Prebiotic Amino Acid Synthesis: A Cautionary Note  

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It is generally thought that the terrestrial atmosphere at the time of the origin of life was CO2-rich and that organic compounds such as amino acids would not have been efficiently formed abiotically under such conditions. It has been pointed out, however, that the previously reported low yields of amino acids may have been partially due to oxidation by nitrite/nitrate during acid hydrolysis. Specifically, the yield of amino acids was found to have increased significantly (by a factor of several hundred) after acid hydrolysis with ascorbic acid as an oxidation inhibitor. However, it has not been shown that CO2 was the carbon source for the formation of the amino acids detected after acid hydrolysis with ascorbic acid. We therefore reinvestigated the prebiotic synthesis of amino acids in a CO2-rich atmosphere using an isotope labeling experiment. Herein, we report that ascorbic acid does not behave as an appropriate oxidation inhibitor, because it contributes amino acid contaminants as a consequence of its reactions with the nitrogen containing species and formic acid produced during the spark discharge experiment. Thus, amino acids are not efficiently formed from a CO2-rich atmosphere under the conditions studied.

Kuwahara, Hideharu; Eto, Midori; Kawamoto, Yukinori; Kurihara, Hironari; Kaneko, Takeo; Obayashi, Yumiko; Kobayashi, Kensei

2012-12-01

222

Modulatory Effects of Ascorbic Acid and ?-tocopherol on Arsenic Induced Micronuclei Formation  

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Full Text Available Arsenic is a well known human carcinogen and has many other toxic effects. Sodium arsenite, a compound of arsenic, capable of inducing genotoxic effects through oxidative stress, is evaluated for its genotoxic effect by the formation of micronuclei in the polychromatic erythrocytes in the bone marrow cells of Wistar rats. Further, the modulatory effects of antioxidants like ascorbic acid and ?-tocopherol on arsenic intoxicated rats is investigated. Therefore, the present study was designed to determine whether the oral supplementation of ?-tocopherol (400 mg kg-1 body weight and ascorbic acid (200 mg kg-1 b.wt. to arsenic-intoxicated rats (100 ppm in drinking water for 30 days, modulates the genotoxicity caused by arsenic through the formation of micronuclei (p<0.05. The findings suggest that co-treatment of ascorbic acid and ?-tocopherol to arsenic-exposed rats protects the antioxidant system and modulates arsenic induced micronuclei formation.

R. Suresh

2010-01-01

223

Equilibrium studies of cellulase aggregates in presence of ascorbic and boric acid.  

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The aggregate formation of cellulase was detected at 300 and 10 mM ascorbic and boric acid respectively. These aggregates showed reduced enzyme activity, loss in near-UV signal, decrease tryptophan and ANS fluorescence. They possess increase in non-native ?-sheet structure as evident from far-UV CD and FTIR spectra, large hydrodynamic radii, increase thioflavin T fluorescence and shift in Congo red. Cellulase at 90 mM ascorbic acid exists as molten globule with retention of secondary structure, altered tryptophan environment, high ANS binding and loss in tertiary structure. Ascorbic acid acts as an antioxidant up to 90 mM and beyond this as a pro-oxidant. PMID:23107806

Iram, Afshin; Amani, Samreen; Furkan, Mohammad; Naeem, Aabgeena

2013-01-01

224

Spectral and paramagnetic properties of oxyhemoglobin solutions exposed to UV-radiation in the ascorbic acid  

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Absorption spectra and ESR of aqueous and aqueous/glyceric solutions of oxyhemoglobin exposed to UV-radiation (250-400 nm) at 293 and 77 K in the presence of ascorbic acid have been analyzed. Vitamin C (5x10-5 M) has been shown to exert a photoprotective effect with regard to oxyhemoglobin (2x10-6 M) UV-irradiated with a dose of 0,86x105 J/m2 at 293 K. The photoprotective effect of ascorbic acid is also displayed after UV-irradiation of frozen (77 K) aqueous/glyceric oxyhemoglobin solutions (2,53x10-5 M). It is concluded that ascorbic acid can be a scavenger with respect to active UV-induced particles in protein systems, including O2. and OH. Proposed is a mode of processes leading to UV-inactivation of hemoprotein molecules

225

Michael reactions of ascorbic acid, 4th communication: nitrostyrene as a Michael acceptor toward vitamin C.  

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The nitrostyrene derivatives 1a-m, prepared by the reaction of nitromethane with the appropriate substituted benzaldehyde, were reacted with ascorbic acid in a Michael type reaction to the new compounds 2a-h. The structural assignment of the resulting mixture of diastereomers could be performed by means of two dimensional homo- and heterocorrelated NMR spectroscopy and comparison to known Michael adducts of ascorbic acid. Catalytic hydrogenolysis of 2a yielded the rearranged compound 7, formed by intramolecular aminolysis in analogy to the rearrangement of the Michael adduct of ascorbic acid and methylvinylketone 3 given in the literature. On testing, the C-nucleoside 7 did not reveal virostatic or cytostatic effects. PMID:8999427

Schmidt, M; Eger, K

1996-01-01

226

In Vitro Effect of a-Tocopherol, Ascorbic Acid and Lycopene on Low Density Lipoprotein Glycation  

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Full Text Available Nonenzymatic glycation of low density lipoprotein (LDL is a reaction of glucose and other reducing sugars with apolipoprotein B100 (apo-B100 lysine residues. In diabetes, this reaction is greatly accelerated and is important in the pathogenesis of diabetic complications. The objective of this study was to investigate in vitro effects of ?-tocopherol, ascorbic acid and lycopene on LDL glycation. LDL was isolated from EDTA-plasma by ultracentrifugation using a single step discontinuous gradient. LDL and glucose were incubated without and with different concentrations of lycopene, ascorbic acid and ?-tocopherol. LDL glycation were estimated by sodium periodate assay. Based on this study results, ?-tocopherol, ascorbic acid and lycopene decrease LDL glycation in a dose dependent manner. The electrophoretic mobility of glycated LDL decreased in presence these nutrients. These effects may be due to antioxidant properties of these nutrients and may have a role in ameliorating atherosclerotic risk of patients with diabetes mellitus.

Mohammad Ali Ghaffari

2007-01-01

227

Electro-oxidation of ascorbic acid catalyzed on cobalt hydroxide-modified glassy carbon electrode  

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Full Text Available The electrochemical behavior of ascorbic acid on a cobalt hydroxide modified glassy carbon (CHM–GC electrode in alkaline solution was investigated. The process of the involved oxidation and its kinetics were established using the cyclic voltammetry, chronoamperometry techniques, as well as by steady state polarization measurements. The results revealed that cobalt hydroxide promotes the rate of oxidation by increasing the peak current; hence ascorbic acid is oxidized at lower potentials, which is thermodynamically more favorable. The cyclic voltammograms and chronoamperometry indicate a catalytic EC mechanism is operative with the electrogeneration of Co(IV as the electrochemical process. Also, the process is diffusion-controlled and the current–time responses follow Cottrellian behavior. This result was confirmed by steady state measurements. The rate constants of the catalytic oxidation of ascorbic acid and the electron-transfer coefficient are reported.

GHASEM KARIM-NEZHAD

2009-05-01

228

Degradation of ascorbic acid and potassium sorbate by different Lactobacillus species isolated from packed green olives.  

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The aim of this research was to ascertain the lactic acid bacteria responsible for the degradation of ascorbic acid and/or potassium sorbate, isolated from packed green olives where these additives had diminished. A total of 14 isolates were recovered from samples of different green olive containers. According to partial sequencing of the 16S rRNA coding gene, Lactobacillus parafarraginis, Lactobacillus rapi, Lactobacillus pentosus, Lactobacillus paracollinoides, and Pediococcus ethanolidurans were identified. With the exception of L. pentosus and L. paracollinoides, the other species had not been mentioned in table olives before this study. Only three of the 14 isolates metabolized ascorbic acid in MRS broth, and the products from ascorbic acid in modified MRS broth without carbon sources were acetic and lactic acids. Except for the two L. rapi and the two P. ethanolidurans strains, the remaining 10 isolates depleted potassium sorbate added into MRS broth to some extent. The product generated by three of these strains was confirmed to be trans-4-hexenoic acid. The degradation of ascorbate or sorbate by lactic acid bacteria should be taken into account when these additives are used in food products where this group of bacteria may be present. PMID:23498172

Montaño, Alfredo; Sánchez, Antonio Higinio; Casado, Francisco Javier; Beato, Víctor Manuel; de Castro, Antonio

2013-05-01

229

Effects of Ascorbic Acid and FSH on the Maturation of Mice's Oocytes and Follicles  

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Full Text Available Introduction: Progress in laboratory culture conditions for in vitro oocyte maturation has led to development of the treatment of human and animal infertility. In this study we investigated the effects of FSH and ascorbic acid on the in vitro maturation of mouse's follicles and enclosed oocytes. Methods: For experiment, intact pre-antral follicles were isolated from the ovaries of 6 week-old female mice and cultured in TCM-199 medium. Special quantities of FSH and ascorbic acid were added to the culture medium (containing 25-30 follicles during separate experiments: 5, 20, 40, 60, 100, 140, 180 and 220 IU/L of FSH and 20, 40, 80, 240, 300 and 400 nmol/mL of ascorbic acid. Follicles were cultured for 6 days in an incubator at 37 °C, 92% humidity and 5% air CO2. Our study was semi-experimental. The entire statistical analysis was carried out by SPSS (version 14.0 for Windows using one way ANOVA. Post Hoc tests were used for the multiple comparisons at 95% confidence interval. P values < 0.05 were considered statistically significant. Results: At FSH concentration of 100 IU/L increase in follicle diameter (190µm, survival rate (91%, germinal vesicle breakdown (GVBD (81% and oocyte maturation rates (61% was observed (p ?0.05. Ascorbic acid increased survival rate (42%, p<0.001 but didn’t affect diameter, GVBD and oocyte maturation rates. Conclusion: Ascorbic acid and FSH-containing medium showed a marked increase in all parameters except for follicle diameter. FSH and ascorbic acid increase the maturation rate of follicles and enclosed oocytes but if they are supplied in a combination, this growth rate can be significantly increased

Barzegari Firouzabadi

2011-11-01

230

Preventive activity of ascorbic acid on lead acetate induced cerebellar damaged in adult Wistar rats  

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Full Text Available Among the environmental contaminants, lead is one of the most hazardous to living matter. In mammals, the main target is the central nervous system, particularly in the young. Ascorbic acid is an antioxidant which is a substance that may protect your cells against the effects of free radicals. This study investigated Experiment the protective effect of ascorbic acid on the cerebellum of adult Wistar rats following oral administration of different doses of Lead acetate. Thirty adult Wistar rats of average weight of 215g were used in this study. The animals were divided into five (5 groups of six animals per group and were administered different doses of lead acetate (60mg/kg bwt of 1/10th LD50 and 30mg/kg bwt of 1/20th of LD50 and ascorbic acid (4.3mg/kg bwt orally over a period of three (3 weeks.Group 1 (control was administered distilled water and Group 2 and 3 were administered 30mg/kg and 60mg/kg of Lead acetate respectively while Group 4 and 5 were given co-administration of 30mg/kg of Lead acetate 4.3mg/kg of ascorbic acid and 60gm/kg of Lead acetate 4.3mg/kg of ascorbic acid respectively. Histopathologically, Lead acetate induced cellular damage in the cerebellum of adult Wistar rats and it was also observed that ascorbic acid prevents or minimize lead-induced cellular damage in the cerebellum of adult Wistar rats.

Sunday Abraham Musa

2012-12-01

231

Effects of Ascorbic Acid and Mono- and Diglycerides on Taftoon Bread Quality  

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Full Text Available The quality of Iranian breads has intensively decreased during recent years due to socio-economic factors and poor quality of flour. The purpose of this study is to investigate the effects of mono- and diglycerides and ascorbic acid as improvers on Iranian bread (Taftoon quality. Three wheat type flours (Ghods, Mahdavi and Roshan wheat varieties produced in Isfahan region were used. The effects of ascorbic acid at three levels (20, 40 and 60 ppm flour basis and esters of mono- and diglycerides at three levels (0.5, 1.0 and 1.5 percent on the dough baking and bread quality were measured. The Taftoon bread was baked in a semi-traditional oven. Loaves of bread were scored after baking and also on the first and second days of storage at room temperature. Analysis of variances indicated that ascorbic acid and mono- and diglycerides have significant effects on the improvement of the rheological properties of dough. However, ascorbic acid had higher effects than mono- and diglycerides. The results of the tests showed that dough resistance to mixing and tensile stress increased with addition of the improvers. Both improvers used in this experiment have an anti-stabling effect on bread. However, the ascorbic acid effect is much less than that of mono- and diglyceride. The low concentration of 0.5 percent of mono- and diglyceride and 60 ppm of ascorbic acid with flours of moderate protein contents (10-11% resulted in good quality Taftoon bread with good organoleptic and tearing qualities after two days.

M. Shahedi

2001-10-01

232

Effect of natural antibrowning agents on color and related enzymes in fresh-cut Fuji apples as an alternative to the use of ascorbic acid.  

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Polyphenoloxidase (PPO) and peroxidase (POD) were evaluated in fresh-cut Fuji apple slices and the effeet of the individual or combined use of ascorbic acid, 4-hexylresorcinol, N-acetylcysteine, and glutathione on their respective activities was determined. Additionally, color changes during storage at 4 degrees C were measured throughout 14 d of storage. PPO activity increased with storage time and was inhibited by the individual use of N-acetylcysteine and glutathione. POD activity in the apple slices was effectively inhibited by the combined use of ascorbic acid with any of the other antibrowning agents. On the other hand, an individual treatment with 1% N-acetylcysteine helped in maintaining the color of fresh-cut apples during 14 d of storage, whereas the use of ascorbic acid was not enough to prevent color deterioration of the apple slices from the 1st day of storage. The results obtained corroborated the effectiveness of other natural antibrowning agents over the traditional use of ascorbic acid in the control of the enzymatic browning in the fresh-cut fruit industry. PMID:19241570

Rojas-Graü, M A; Soliva-Fortuny, R; Niartín-Belloso, O

2008-08-01

233

Inhibition of cell proliferation and migration by oxidative stress from ascorbate-driven juglone redox cycling in human bladder-derived T24 cells  

International Nuclear Information System (INIS)

Highlights: ? The cytotoxicity of juglone is markedly increased by ascorbate. ? T24 cell death by oxidative stress is necrosis-like. ? Redox cycling by juglone/ascorbate inhibits cell proliferation. ? Cellular migration is impaired by juglone/ascorbate. -- Abstract: The effects of juglone on T24 cells were assessed in the presence and absence of ascorbate. The EC50 value for juglone at 24 h decreased from 28.5 ?M to 6.3 ?M in the presence of ascorbate. In juglone-treated cells, ascorbate increased ROS formation (4-fold) and depleted GSH (65%). N-acetylcysteine or catalase restricted the juglone/ascorbate-mediated effects, highlighting the role of oxidative stress in juglone cytotoxicity. Juglone alone or associated with ascorbate did not cause caspase-3 activation or PARP cleavage, suggesting necrosis-like cell death. DNA damage and the mild ER stress caused by juglone were both enhanced by ascorbate. In cells treated with juglone (1–5 ?M), a concentration-dependent decrease in cell proliferation was observed. Ascorbate did not impair cell proliferation but its association with juglone led to a clonogenic death state. The motility of ascorbate-treated cells was not affected. Juglone slightly restricted motility, but cells lost their ability to migrate most noticeably when treated with juglone plus ascorbate. We postulate that juglone kills cells by a necrosis-like mechanism inhibiting cell proliferation and the motility of T24 cells. These effects are enhanced in the presence of ascorbate.

234

6-Deoxy-6-[18F]fluoro-L-ascorbic acid. Tissue biodistribution in ascorbic acid-deficiency and RG-C6 glioma bearing rats  

International Nuclear Information System (INIS)

A comparative study in Wistar normal rats and ODS rats unable to synthesize ascorbic acid showed that the radioactivity distribution in tissues after i. v. injection of 6-deoxy-6-[18F]fluoro-L-ascorbic acid (18F-DFA) was not significantly influenced by the vitamin C status of the animal. Biodistribution studies in Wistar male rats implanted with RG-C6 glioma intracerebrally demonstrated that 18F-DFA had low tumor localization (0.17% dose/g at 30 min and 0.16% dose/g at 60 min) with very little specific distribution compared with non-target brain tissues. These results indicate that the use of 18F-DFA may not be a candidate for imaging brain tumor by PET. (author)

235

Ascorbic acid enhances the decrease in peroxidase activity in inflamed tissues of mice.  

Science.gov (United States)

The aim of this study was to explore whether intraperitoneal administration of ascorbic acid (AA) at a dose of 500 mg/kg, once a day for 3 following days, affected the peroxidase (PO) activity in inflamed feet of mice. The foot inflammatory reaction induced by the carrageenan (CAR), n-formyl-methionyl-leucyl-phenylalanine (FMLP) and xanthine-xanthine oxidase was accompanied by suppression of PO activity. Administration of AA, having no effect on the degree of foot oedema, skin temperature and microscopic picture of tissue specimens significantly enhanced the decline in PO activity provoked by inflammatory agents. This activity decreased 2.0-, 1.6- and 1.9-fold (p < 0.001, p < 0.01, p < 0.05) when inflammatory response was induced with FMLP, CAR and X-XO, respectively. Also in vitro AA (50-100 micrograms/ml) inhibited PO activity of leukocyte lysate and foot extract obtained from untreated animals. In conclusion we found that AA, having no effect on inflammatory response, significantly enhanced inhibition of PO activity in inflamed tissues in mice which could be a result of direct action of AA on the enzyme molecule. PMID:8010873

Nowak, D; S?odkowska, J; Pietras, T; Piasecka, G; Antczak, A; Król, M

1993-01-01

236

Intravenous ascorbic acid protocol for cancer patients: scientific rationale, pharmacology, and clinical experience  

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Full Text Available ABSTRACTBackground: Ascorbic acid (vitamin C, ascorbate has been shown to protect cells against various types of oxidant injury at physiologically relevant concentrations. Vitamin C has been suggested as having both a preventative and therapeutic role in a number of pathologies when administered at much higher-than-recommended dietary allowance levels. This article reviews the scientific rational for intravenous vitamin C as a potential treatment for cancer. Many mechanisms of action for ascorbate efficacy against cancer have been proposed over the years. Cancer patients are often deficient in vitamin C, and require large doses to replenish depleted stores. It has been demonstrated in vitro and in animal studies that vitamin C is preferentially toxic to tumor cells at millimolar concentrations; moreover, pharmacokinetic data suggest that these concentrations are clinically achievable when ascorbate is administered intravenously. Data suggests that ascorbate may serve as a biological response modifier, affecting inflammation and angiogenesis as well as improving immune function parameters. While Phase II clinical trials using ascorbate in cancer therapy are under way, vitamin C is not subject to the regulations that synthetic drugs are and therefore has been used clinically for decades to treat cancer patients. This clinical experience suggests the therapy is safe, and may be effective in some instances. Attached to this article is the Riordan IVC Protocol, which details an intravenous vitamin C protocol that can be safely administered to cancer patients.Keywords: Cancer, inflammation, C-reactive protein, inflammatory cytokines, high-dose vitamin C

Mikirova NA

2013-08-01

237

The Effect of Ascorbic Acid on Cadmium Exposure in the Gills of Puntius altus  

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Full Text Available The effects of cadmium and ascorbic acid on the gills of Red-tailed tinfoil barb (Puntius altus were compared using light and scanning electron microscopic study for the period 24, 48, 72 and 96 h. The main alterations in the cadmium treated group were edema, filament cell proliferation, lamellar cell hyperplasia, lamellar fusion, epithelial lifting and aneurysm. These changes occurred predominantly in the 96 h treatment. In the combination of cadmium and ascorbic acid treated group, they showed similar alterations as those observed in the cadmium treated alone group but they were less severe.

Piya Kosai

2007-01-01

238

IMPROVEMENT OF SALT TOLERANCE IN DURUM WHEAT BY ASCORBIC ACID APPLICATION  

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The main objective of this study is to examine whether exogenously applied Ascorbic acid (AsA) may enhance the salt tolerance in durum wheat (Triticum durum Desf. var. Waha). Two weeks old seedling, grown in plastic pots of 1kg, were subjected to salt stress by adding 25ml of NaCl (150mm), and treated or not with the addition of ascorbic acid (0.7 mM). Two weeks after salt stress, plants were harvested and the various measures were recorded.The effects of salt stress, in the presence and abse...

Fercha Azzedine; Hocine Gherroucha; Mebarek Baka

2011-01-01

239

Visible light-induced oxidation of ascorbic acid and formation of hydrogen peroxide  

International Nuclear Information System (INIS)

Photosensitized oxidation of ascorbic acid and the formation of hydrogen peroxide using tris(2,2'-bipyridine)ruthenium(II), Ru(bpy)32+, proceed simultaneously in oxygen containing an aqueous solution of ascorbic acid with the illumination of visible light. The mechanism of the reaction has been suggested from the rate dependence on the solute concentrations and from quenching experiments. The charge separation could be achieved as the result of scavenging Ru(bpy)33+, which is formed by the reaction of the lowest excited state species of Ru(bpy)32+ with O2. (author)

240

Tear ascorbic acid levels and the total antioxidant status in contact lens wearers: A pilot study  

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Full Text Available Aims: The tear ascorbate owing to its high concentration, functions as an effective antioxidant against the oxidative damage of cornea. Contact lens wearers (CLW are prone to oxidative stress due to the lens-induced hypoxic conditions. A pilot study was done to compare the tear ascorbic acid level and the total antioxidant capacity give as in normal and CLW. Materials and Methods: In this study 21 CLW (Mean age 23 ± 3 years ; M-2, F-19, who were daily wear users, with duration of wear not more than four years, along with age-matched 28 controls (Mean age 28 ± 3 ; M-15, F-13 were recruited in the study for collection of reflex tears using Schirmer?s strip. Ascorbic acid in tears was determined using high-performance liquid chromatography (HPLC, total antioxidant capacity (TAC and total protein assay by spectrophotometric analysis. Results: CLW showed no significant change in the tear ascorbic acid levels (0.4 ± 0.26 mM compared to the control subjects (0.61 ± 0.59 mM. The amount of ascorbic acid in tears did not correlate with the TAC or the total protein of the tears. The mean TAC in CLW was 0.69 ± 0.16 mM, with a total protein of 1.35 ± 0.46?mg/ml while in controls it was 0.7 ± 0.18 mM and 1.21 ± 0.47 mg/ml respectively . Conclusions: Soft contact lens wear did not show any significant change in tear ascorbic acid, TAC and total protein levels compared to controls.

Venkata Sai

2009-01-01

 
 
 
 
241

L-Ascorbic acid as an alternative fuel for direct oxidation fuel cells  

Energy Technology Data Exchange (ETDEWEB)

L-Ascorbic acid (AA) was directly supplied to polymer electrolyte fuel cells (PEFCs) as an alternative fuel. Only dehydroascorbic acid (DHAA) was detected as a product released by the electrochemical oxidation of AA via a two-electron transfer process regardless of the anode catalyst used. The ionomer in the anode may inhibit the mass transfer of AA to the reaction sites by electrostatic repulsion. In addition, polymer resins without an ionic group such as poly(vinylidene fluoride) and poly(vinyl butyral) were also useful for reducing the contact resistance between Nafion membrane and carbon black used as an anode, although an ionomer like Nafion is needed for typical PEFCs. A reaction mechanism at the two-phase boundaries between AA and carbon black was proposed for the anode structure of DAAFCs, since lack of the proton conductivity was compensated by AA. There was too little crossover of AA through a Nafion membrane to cause a serious technical problem. The best performance (maximum power density of 16 mW cm{sup -2}) was attained with a Vulcan XC72 anode that included 5 wt.% Nafion at room temperature, which was about one-third of that for a DMFC with a PtRu anode. (author)

Fujiwara, Naoko; Yamazaki, Shin-ichi; Siroma, Zyun; Ioroi, Tsutomu; Yasuda, Kazuaki [Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)

2007-05-01

242

Selective Detection of Dopamine in the Presence of Ascorbic Acid at Poly (m-Aminobenzene Sulfonic Acid  

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Full Text Available Poly (m-aminobenzene sulfonic acid, m-ABSA films were electrochemically prepared by cyclic voltammetry (CV in 0.1 mol L–1 KCl solution. The dopamine (DA selectivity of polymeric electrodes prepared at the different thicknesses was examined in the presence of ascorbic acid (AA. The results showed that the modified electrode showed an excellent electrocatalytical effect towards oxidation of dopamine (DA and ascorbic acid (AA. Electrostatic interaction between the negatively charged poly(m-ABSA film and either cationic DA species or anionic AA species favorably contributed to the redox response of DA and AA. Moreover, the regular and repetitive responses for dopamine were obtained even in the presence of the some interfering substances such as ascorbic acid, NaCl, NaClO4, Na2SO4 ,NaNO3 and KCl.

Gamze Erdo?du

2011-09-01

243

Neonatal hypertyrosinemia and evidence for deficiency of ascorbic acid in Arctic and subarctic peoples.  

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Hypertyrosinemia tyrosine concentration in whole blood greater than 0.42 mmol/l or 7.5 mg/dl is prevalent among lnuit newborn of the Canadian Eastern Arctic. The rate was 14.8 per 100 newborn between January 1970 and December 1972 (first survey period) and 6.2/100 between January 1973 and September 1974 (second survey period); the corresponding rates among Indian newborn of Nouveau Quebec were 2.6 and 2.2%. Among Anglo-Saxons the rate was less than 0.5% and in French Canada it commonly exceeded 0.94%. Serum concentrations of ascorbic acid were low (less than or equal to 0.25 mg/dl) in the pregnant and age-matched adult lnuit when measured by Nutrition Canada during the first survey period. The percentages of inuit children (up to 4 years old) and pregnant women at "high risk" for scurvy (serum concentration of ascorbic acid less than 0.2 mg/dl) were 14.8 and 47.1, respectively; the corresponding national percentages were 3.0 and 2.2, respectively. Deficiency of ascorbic acid in pregnant women is probably the cause of the unusual prevalence of neonatal hypertyrosinemia among the native Arctic and subarctic peoples because ascorbic acid is required to maintain optimal activity of p-hydroxyphenylpyruvic acid hydroxylase and to permit normal oxidation of tyrosine. PMID:1181017

Clow, C L; Laberge, C; Scriver, C R

1975-10-01

244

Modification of ascorbic acid using transglycosylation activity of Bacillus stearothermophilus maltogenic amylase to enhance its oxidative stability.  

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Ascorbic acid (1), a natural antioxidant, was modified by employing transglycosylation activity of Bacillus stearothermophilus maltogenic amylase with maltotriose and acarbose as donor molecules to enhance its oxidative stability. The transglycosylation reaction with maltotriose as donor created mono- and di-glycosyl transfer products with an alpha-(1,6)-glycosidic linkage. In addition, two acarviosine-glucosyl transfer products were generated when transglycosylation was performed with acarbose as a donor. All transfer products were observed by TLC and HPLC, and purified by Q-sepharose anion exchange and Biogel P-2 gel permeation chromatographies. LC/MS and (13)C NMR analyses revealed that the structures of the transfer products were 6-O-alpha-D-glucosyl- (2) and 6-O-alpha-D-maltosyl-ascorbic acids (3) in the reaction of maltotriose, and 6-O-alpha-acarviosine-D-glucosyl- (4) and 2-O-alpha-acarviosine-D-glucosyl ascorbic acids (5) in the reaction of acarbose. The stability of the transglycosylated ascorbic acid derivatives was greatly enhanced against oxidation by Cu(2+) ion and ascorbate oxidase. Among them, compound 3 proved to be the most stable against in vitro oxidation. The antioxidant effects of glycosyl-derivatives of ascorbic acid on the lipid oxidation in cooked chicken breast meat patties indicated that they had antioxidant activities similar to that of ascorbic acid. It is suggested that the transglycosylated ascorbic acids can possibly be applied as effective antioxidants with improved stability in food, cosmetic, and other applications. PMID:12010003

Bae, Hee-Kyung; Lee, Soo-Bok; Park, Cheon-Seok; Shim, Jae-Hoon; Lee, Hye-Young; Kim, Myo-Jeong; Baek, Jin-Sook; Roh, Hoe-Jin; Choi, Jin-Hwan; Choe, Eun-Ok; Ahn, Dong-Uk; Park, Kwan-Hwa

2002-05-22

245

Simultaneous determination of ascorbic acid, uric acid and neurotransmitters with a carbon ceramic electrode prepared by sol-gel technique.  

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A sol-gel carbon composite electrode (CCE) has been prepared by mixing a sol-gel precursor (e.g. methyltrimethoxysilane) and carbon powder without adding any electron transfer mediator or specific reagents. It was demonstrated that this sensor can be used for simultaneous determination ascorbic acid, neurotransmitters (dopamine and adrenaline) and uric acid. Direct electrochemical oxidation of ascorbic acid, uric acid and catecholamines at a carbon composite electrode was investigated. The experimental results were compared with other common carbon based electrodes, specifically, boron doped diamond, glassy carbon, graphite and carbon paste electrodes. It was found that the CCE shows a significantly higher of reversibility for dopamine. In addition, in comparison to the other electrodes used, for CCE the oxidation peaks of uric acid, ascorbic acid and catecholamines in cyclic and square wave voltammetry were well resolved at the low positive potential with good sensitivity. The advantages of this sensor were high sensitivity, inherent stability and simplicity and ability for simultaneous determination of uric acid, catecholamines and ascorbic acid without using any chromatography or separation systems. The analytical performance of this sensor has been evaluated for detection of biological molecules in urine and serum as real samples. PMID:18970846

Salimi, Abdollah; Mamkhezri, Hussein; Hallaj, Rahman

2006-11-15

246

The Effect of Oral Ascorbic Acid Pretreatment on Feeding Changes Following Injection in Nucleus Accumbens Shell in Adult Male Rats  

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Full Text Available Background: Ascorbic acid (AA is not synthesized in the brain but it is actively transported through blood-brain barrier by SVCT2 cotransporter and it is stored in high concentrations with heterogeneous distribution in areas such as nucleus accumbens shell (AcbSh in the mammalian brain. Previous studies have shown that Ascorbic acid injection into AcbSh decreases feeding; therefore, in the present study we evaluated the effects of oral Ascorbic acid pretreatment on changes in feeding upon its injection in AcbSh in adult male rats.Methods: Sixty-three adult male rats (220-280 g were divided into five treatment and five pretreatment groups. The treatment groups included the control (intact group, sham-operated Ascorbic acid group that received normal saline as vehicle, and three other groups that received different doses of ascorbic acid (10, 50 and 250 µg/rat by injection into AcbSh for four days. The pretreatment groups received Ascorbic acid (100 mg/kg for 15 days via gastric gavage before receiving the aforementioned doses in treatment groups into intra nucleus AcbSh. Feeding measurement was repeated every 12 hours by automatic metabolic cage.Results: The results indicated that all injected doses of Ascorbic acid (10, 50 and 250 µg/rat into nucleus accumbens shell decrease food intake (P<0.05 in rats and oral Ascorbic acid pretreatment had no effects in this regard.Conclusion: Our findings show that ascorbic acid is an effective factor in feeding regulation. Oral pretreatment seems to have no influence on the central effects of ascorbic acid in the nucleus accumbens shell.

Badreh F

2012-02-01

247

The Inhibitory Effects of Ascorbic Acid, ?-Tocopherol, and Sodium Selenite on Proliferation of Breast Cancer Cell Lines  

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Full Text Available The role of antioxidants in prevention and treatment of cancers have been reported by several studies. In our investigation we studied the effects of ascorbic acid, ?-tocopherol, and sodium selenite on proliferation of two breast cancer cell lines: T47D (estrogen-receptor positive and MDA-MB-231 (estrogen-receptor negative. We also used 17-?-estradiol as positive control for proliferation of T47D cells. The viability of cells after 7 days of exposure to different concentrations of test compounds was determined by resazurine based method. Ascorbic acid and ?-tocopherol significantly inhibited cell growth at a concentration of 10-4 M in both cell lines and antagonized the cell proliferation induced by 17-?-estradiol in T47D cells. Sodium selenite at concentrations above 10-6 M strongly inhibited the cell growth in both cell lines andsuppressed the stimulated growth of T47D cells by 17-?-estradiol. Our results with different strengths of activity of test compounds, further confirmed the findings of previous studies that showed the inhibitory effects of these antioxidants on other malignant cell lines.

Ebrahim Azizi

2003-01-01

248

Factors that affect leaf extracellular ascorbic acid content and redox status  

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Leaf ascorbic acid content and redox status were compared in ozone-tolerant (Provider) and ozone-sensitive (S156) genotypes of snap bean (Phaseolus vulgaris L.). Plants were grown in pots for 24 days under charcoal-filtered air (CF) conditions in open-top field chambers and then maintained as CF controls (29 nmol mol{sup 1} ozone) or exposed to elevated ozone (71 nmol mol{sup 1} ozone). Following a 10-day treatment, mature leaves of the same age were harvested early in the morning (06:00-08:00 h) or in the afternoon (13:00-15:00 h) for analysis of ascorbic acid (AA) and dehydroascorbic acid (DHA). Vacuum infiltration methods were used to separate leaf AA into apoplast and symplast fractions. The total ascorbate content [AA + DHA] of leaf tissue averaged 28% higher in Provider relative to S156, and Provider exhibited a greater capacity to maintain [AA + DHA] content under ozone stress. Apoplast [AA + DHA] content was 2-fold higher in tolerant Provider (360 nmol g{sup 1} FW maximum) relative to sensitive S156 (160 nmol g1 FW maximum) regardless of sampling period or treatment, supporting the hypothesis that extracellular AA is a factor in ozone tolerance. Apoplast [AA + DHA] levels were significantly higher in the afternoon than early morning for both genotypes, evidence for short-term regulation of extracellular ascorbate content. Total leaf ascorbate was primarily reduced with AA/[AA + DHA] ratios of 0.81-0.90. In contrast, apoplast AA/[AA + DHA] ratios were 0.01-0.60 and depended on genotype and ozone treatment. Provider exhibited a greater capacity to maintain extracellular AA/[AA + DHA] ratios under ozone stress, suggesting that ozone tolerance is associated with apoplast ascorbate redox status. (au)

Burkey, K.O.; Fiscus, E.L. [North Carolina State Univ., United States dept. og Agriculture-Agricultural Research Service and Dept. of Crop Science, Raleigh, NC (United States); Eason, G. [North Carolina, State Univ., United States Dept. of Plant Pathology, Raleigh, NC (United States)

2003-01-01

249

INFLUENCES OF THIAMINE AND/OR ASCORBIC ACID ON LEAD INTOXICATION  

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Full Text Available The effects of thiamine, ascorbic acid ami their combination an workers who are continuously exposal to lead has been investigated. In this study 60 persons in a Battery industry was selected and divided into four equal groups. Group I received placebo, group II thiamine (300 mg, group III ascorbic acid (250 mg anil group IV thiamine (300 mg plus ascorbic acid (250 mg three times a day (Orally. At beginning of the study and after one month of above drug regimen; blood, urine and a questionnaire about their clinical signs were examined. 'there were no significant differences between blood anil urine lead level in all groups after treatment. Zinc protoporphyrin (zpp level showed a significant reduction in ascorbic acid treated group (group III as compared to pretreatment. Clinical manifestation improved in the group that received both vitamins (group IV. However, from a clinical stand point, it appears the usage of these vitamins may have a beneficial effects in lead occupational exposure.

M. Ghazi-Khansari

1996-07-01

250

ECOPHYSIOLOGICAL INFLUENCE ON ASCORBIC ACID AND GLUTHATION CONTENT IN SPRING BARLEY SEED ?????????????????? ??????? ?? ?????????? ????????????????? ?????????????? ? ????? ??????? ??????? ??????  

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Full Text Available The content of ascorbic acid (AA and glutathione (GSH in spring barley seed of four varieties depends upon hydro-temperature environment (HTE in different way. The genotype and HTE have equal input on AA content (35 and 34,8 %, and GSH content depends mainly upon “genotype-HTE” interaction (67,6 %.

Kovaljeva O. N.

2011-06-01

251

Effect of L-ascorbic Acid on Nili Ravi Buffalo Oocytes During in vitro Maturation  

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Full Text Available The present study was conducted to investigate the effect of L-ascorbic acid (AsA on Nile Ravi buffalo oocytes. Cumulus Enclosed Oocytes (CEOs and Cumulus Denuded Oocytes (CDOs were cultured for 24 h in TCM-199 supplemented with Recombinant Human Follicular Stimulating Hormone (RhFSH, 0.4% Bovine Serum Albumin (BSA, oestradiol and Gentamycin. Nili Ravi buffalo oocytes with or free from cumulus cells were exposed to 250 ?M AsA. Meiotic maturation, degeneration of oocytes was assessed at different maturation time (0, 12, 24 h. CDOs treated with L-ascorbic acid resumed meiosis and oocytes were significantly (p<0.05 increased to MII stage. Where as CDOs matured in control medium with out L-ascorbic acid supplementation did not show any significant increase in MII oocytes proportion as the maturation time was extended to 24 h (p<0.05. In present study it was observed that cumulus cells are involved in protection against degeneration as CEOs treated in control medium the degenerated oocytes high significantly (p<0.05 decreased to 7.40% as compared to CDOs in which 21.4% oocytes were found to be degenerated. These results indicate that exposure to L-ascorbic acid promote the development of the Nili Ravi buffalo CDOs and cumulus cells are involved in protection against degeneration of oocytes.

Ikram Ullah

2006-01-01

252

CAPSAICIN AND ASCORBIC ACID VARIABILITY IN CHILLI AND PAPRIKA CULTIVARS AS REVEALED BY HPLC ANALYSIS  

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Full Text Available Capsaicin and ascorbic acid contents of seven Indian peppers varieties/accessions from Capsicum annuum (CA 97, CCH, K1, KTPL19, Arka Abhir and Bayadagi Kaddi and C. frutescens (CF1 species were determined using High Performance Liquid Chromatography (HPLC. Based on their pungency value, all the chilli accession/varieties (CA 97, CCH, K1, and CF 1 were classified as highly pungent peppers. The accession CF1 showed the highest concentration of capsaicin (445mg 100g -1 DW with corresponding pungency value of 71,200 SHUs and Arka Abhir variety showed the lowest capsaicin concentration (29mg 100g -1 DW with 4,672 SHUs of pungency value. Similarly, Bayadaggi kaddi variety showed the highest ascorbic acid content (189 mg/100 FW and the accession CA 97 showed the lowest ascorbic acid contents (55.3 mg/100 FW. The variability in capsaicin and ascorbic acid content presented in the pepper germplasm can be exploited for breeding cultivars with improved nutritional qualities. Moreover, CF1and Bayadagi kaddi can be used as a potential source for capsaicin and vitamin C, respectively.

Samuel Tilahun

2013-08-01

253

CAPSAICIN AND ASCORBIC ACID VARIABILITY IN CHILLI AND PAPRIKA CULTIVARS AS REVEALED BY HPLC ANALYSIS  

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Full Text Available Capsaicin and ascorbic acid contents of seven Indian peppers varieties/accessions from Capsicum annuum (CA 97, CCH, K1, KTPL19, Arka Abhir and Bayadagi Kaddi and C. frutescens (CF1 species were determined using High Performance Liquid Chromatography (HPLC. Based on their pungency value, all the chilli accession/varieties (CA 97, CCH, K1, and CF 1 were classified as highly pungent peppers. The accession CF1 showed the highest concentration of capsaicin (445mg 100g -1 DW with corresponding pungency value of 71,200 SHUs and Arka Abhir variety showed the lowest capsaicin concentration (29mg 100g -1 DW with 4,672 SHUs of pungency value. Similarly, Bayadaggi kaddi variety showed the highest ascorbic acid content (189 mg/100 FW and the accession CA 97 showed the lowest ascorbic acid contents (55.3 mg/100 FW. The variability in capsaicin and ascorbic acid content presented in the pepper germplasm can be exploited for breeding cultivars with improved nutritional qualities. Moreover, CF1and Bayadagi kaddi can be used as a potential source for capsaicin and vitamin C, respectively.

Samuel Tilahun

2013-10-01

254

Effect of ascorbic acid on food preference and consumption in captive capybaras (Hydrochoerus hydrochaeris  

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Full Text Available The aim of this work was to study the short and long term influences of ascorbic acid on Hydrochoerus hydrochaeris, if supplemented in their food. No differences regarding food intake were observed in the absence of vitamin C. On a daily basis, animals accustomed to food containing ascorbic acid prefered to continue eating the same food. Food preference in capybaras did not seem to depend on ascorbic acid availability; however, when accustomed to vitamin C, capybaras might recognize and select ascorbic acid in subsequent food. Mechanisms allowing capybaras to "evaluate" the nutritional quality of their food are discussed, as well as the adaptive value of this behavior in free ranging populations.O ácido ascórbico é um nutriente essencial para as capivaras (Hydrochoerus hydrochaeris. No presente trabalho foi avaliado o efeito do ácido ascórbico sobre o consume e as preferências alimentares a curto e longo prazo, assim como a influencia da escolha sobre a sintomatologia da carência de vitamina C na dieta. Não foram observadas diferencias no consumo de alimento na ausência deste nutriente. Considerando as preferências a longo prazo (24h, os animais acostumados a consumir vitamina C continuavam consumindo preferencialmente o alimento suplementado. As preferências alimentares em capivaras não parecem depender da disponibilidade de ácido ascórbico; no entanto, quando acostumados à vitamina C, estes animais podem reconhecer e selecionar o ácido ascórbico na alimentação subseqüente. São discutidos os mecanismos que permitem as capivaras "avaliar" a qualidade nutricional do alimento, assim como o valor adaptativo destes comportamentos em populações silvestres.

Martín Roberto Alvarez

2009-06-01

255

Effect of preservation method and storage condition on ascorbic acid loss in beverages  

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Full Text Available Global market is flooded with vitamin-enriched foods, mainly beverages. Major vitamins for enriching beverages are the antioxidant vitamins A, C and E. Ascorbic acid is readily oxidized and lost during storage of the beverages, at rates depending on the conditions of storage. This fact is of great importance for the consumer who must know how to store beverages and when to consume them in order to get the maximum benefit of added vitamin C. The objective of this paper was to determine the amount of ascorbic acid lost in beverages applying different preservation methods and storage condition. Beverage was made in laboratory conditions with synthetic L-ascorbic acid added according to the national legislations. After 30 days of storage at 4-8oC ascorbic acid overall loss was from 81.01% to 90.27% in thermally pasteurized samples and from 97.83 % to almost complete loss in samples preserved with sodium benzoate.

Jokanovi? Marija R.

2009-01-01

256

Combined metoprolol and ascorbic acid treatment prevents intrinsic damage to the heart during diabetic cardiomyopathy.  

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Metabolic disturbances and oxidative stress have been highlighted as potential causative factors for the development of diabetic cardiomyopathy. The ?-blocker metoprolol is known to improve function in the diabetic rat heart and ameliorates the sequelae associated with oxidative stress, without lowering oxidative stress. The antioxidant ascorbic acid is known to improve function in the diabetic rat heart. We tested whether a combination of ascorbic acid and metoprolol treatment would improve function further than each drug individually. Control and streptozotocin-induced diabetic Wistar rats were treated with metoprolol (15 mg·(kg body mass)(-1)·day(-1), via an osmotic pump) and (or) ascorbic acid (1000 mg·(kg body mass)(-1)·day(-1), via their drinking water). To study the effect of treatment on the development of dysfunction, we examined time points before (5 weeks diabetic) and after (7 weeks diabetic) development of overt systolic dysfunction. Echocardiography and working-heart-perfusion were used to assess cardiac function. Blood and tissue samples were collected to assess the severity of disease and oxidative stress. While both drugs improved function, only ascorbic acid had effects on oxidative damage. Combination treatment had a more pronounced improvement in function. Our ?-blocker + antioxidant treatment strategy focused on oxidative stress, not diabetes specifically; therefore, it may prove useful in other diseases where oxidative stress contributes to the pathology. PMID:25229873

Saran, Varun; Sharma, Vijay; Wambolt, Richard; Yuen, Violet G; Allard, Michael; McNeill, John Hugh

2014-10-01

257

Factors affecting plasma Contents of thiamine and Ascorbic acid in Camels (Camelus dromedarius  

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Full Text Available The study was designed to investigate the effect of age, breed, sex, and breeding season on thiamine and ascorbic acid status (AA in camels (Camelus dromedarius. A total of 375 camels were sampled over a one-year field survey in Butana area, Central Sudan. No effect of sex on thiamine and ascorbic acid levels was observed. The breeding male and female camels showed higher status of plasma thiamine and lower ascorbic acid as compared to non-breeding camels. Thiamine plasma contents showed variation with respect to age. The thiamine plasma levels for neonate, yearling, and adult were 59.94.4, 70.58.9 and 88.96.7 g/L, respectively. The corresponding figures for AA were 6.21.0, 4.90.9, and 4.50.8 mg/L, respectively. The Arabi showed higher ascorbic acid (5.91.0 than Anafi (4.20.9 mg/L. However, no significant breed variation for thiamine status was indicated.

Mohamed, H. E.

2006-01-01

258

Alpha-tocopherol and Ascorbic Acid Combinations Influence the Maturation of Sheep Oocytes  

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Full Text Available The goal of this research was to establish whether supplementation with combinations of ?-tocopherol and ascorbic acid could improve the maturation and expansion of sheep cumulus-oocyte complexes. Sheep oocytes were cultured for 24 hours at 37°C in 5.4% CO2 atmosphere in M199 containing 20 ?M ?-tocopherol+750 ?M ascorbic acid or 5 ?M ?-tocopherol+250 ?M ascorbic acid. Afterwards, cumulus oophorus expansion was assessed and oocytes were denuded. The presence of the first polar body was assessed by fluorescent staining with Hoechst 33258. Differences between treatments were analyzed by the analysis of variance and interpreted using the LSD test. Supplementation with the combination of 20 ?M ?-tocopherol+750 ?M ascorbic acid resulted in significantly greater (p<0.05 percentages of COCs that were scored as 3. However, the number of COCs scored at 4 decreased. The same dynamic could be seen when oocytes were checked for the presence of the first polar body. Percentages decreased with the increase in antioxidant concentration. This indicates that although antioxidants, in these particular concentrations have been proven to have a positive influence on swine oocyte maturation the same cannot be said for ovine female gametes.

Ileana Miclea

2012-05-01

259

A method for the determination of ascorbic acid using the iron(II)-pyridine-dimethylglyoxime complex  

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A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 {mu}g ml{sup -1}. Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C. [Italiano] Si propone un rapido e semplice metodo spettrofotometrico per la determinazione dell`acido ascorbico. L`acido ascorbico riduce il ferro(III) a ferro(II) che forma con la dimetilgliossima, in presenza di piridina, un complesso colorato in rosso. L`assorbanza della soluzione risultante e` misurata a 514 nm e si ottiene una relazione lineare tra assorbanza e concentrazione dell`acido ascorbico fino a 14 {mu}g ml{sup -1}. Si sono condotti studi sugli interferenti usualmente associati all`acido ascorbico ed e` stata valutata l`applicabilita` del metodo all`analisi di preparati farmaceutici di vitamina C.

Arya, S. P.; Mahajan, M. [Haryana, Kurukshetra Univ. (India). Dept. of Chemistry

1998-05-01

260

Exogenous application of ascorbic acid stimulates growth and photosynthesis of wheat (Triticum aestivum L. under drought  

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Full Text Available Drought causes considerable reduction in plant growth. A hydroponic experiment was conducted to appraise the potential role of exogenously applied ascorbic acid in alleviating the effect of drought on wheat. Two contrasting wheat genotypes, a drought tolerant cultivar Chakwal-86 and a drought sensitive strain 6544-6 were used in the study. Drought was induced by dissolving 20% Polyethylene glycol (PEG8000 in the nutrient solution producing -0.6MPa osmotic stress. Drought caused a significant decrease in chlorophyll pigments and net photosynthesis resulting in growth reduction of both wheat genotypes. However, this decrease was more severe in the genotype 6544-6 compared to Chakwal-86. Ascorbic acid (AsA was applied through rooting medium, as a foliar spray and seed soaking treatment. Ascorbic acid treated seedlings of both genotypes maintained higher chlorophyll contents, net photosynthesis and growth compared to the non-treated plants. Of the three different modes of ascorbic acid application, rooting medium was more effective in alleviating the adversities of drought in wheat. `

Samina Malik and Muhammad Ashraf

2012-05-01

 
 
 
 
261

Enhancing Lipid Stability in Irradiated Beef Mince by Oleoresins and/ or Ascorbic Acid during Chilling Storage  

International Nuclear Information System (INIS)

Lipid Oxidation, fatty acids profile and sensory properties of irradiated beef mince (2.5 kGy) treated with oleoresins (rosemary or ginger), ascorbic acid, or combination of ascorbic acid and oleoresins were investigated during 30 days of chilled storage. Thiobarbituric acid reactive substances (TBARS) as an indication of lipid oxidation, of irradiated control samples were significantly higher than those of non irradiated control and samples treated with rosemary and ginger oleoresins. By GC-MS analysis, it was found that the relative percentage of total saturated fatty acids (TSFA) increased in all treatments. However, the highest increase was recorded in irradiated control samples compared to non irradiated control samples. Beef mince samples treated with oleoresins (rosemary or ginger) had the best scores for discoloration and off odour. Thus, the addition of oleoresins (rosemary or ginger) to beef mince before irradiation could be an easily applied method to minimize oxidative degradation of irradiated meat

262

Distribution of ascorbate-2-sulfate and distribution, half-life and turnover rates of [1-14C]ascorbic acid in rainbow trout  

International Nuclear Information System (INIS)

Rainbow trout (250 g) were maintained at 15 degrees C for 3 months on a low ascorbic acid diet, given [1-14C]ascorbic acid by gavage, then fed the NAS/NRC requirement 12 times per week. Total urine, fecal water and branchial water were collected daily from five fish placed in metabolism chambers for four successive 5-day periods. Tissue samples were analyzed for 14C, ascorbic acid (C1) and ascorbate-2-sulfate (C2). Excretion analysis indicated t1/2 . 42 days. After 20 days, the feeding schedule was changed to 3 times per week. Fish fed 14C were sampled after 1, 2, 3 and 4 months. The half-life in each organ except brain was inversely proportional to the dietary level of ascorbate. Concentrations of C1 and C2 in the various tissues reflected dietary intake of vitamin C. Total C (CT . C1 + C2) levels were maintained in the liver even with the low vitamin C diet. Estimates of body pool for C1 are 27-29 mg/kg. At the higher ascorbate intake CT was 92-114 mg/kg, but decreased by 34% at the lower feeding rate to 51-62 mg/kg. Data indicate that there are two or more body pools that include a store of C2, which is readily interconverted in metabolizing tissues to and from C1. Since air and water stable C2 is antiscorbutic for fish, it is the preferred form of ascorbate for fish feeds

263

Impact of Exogenous Ascorbic Acid on Antioxidant Activity and Some Physiological Traits of Common Bean Subjected to Salinity Stress  

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Full Text Available The role of ascorbic acid as a key molecule antioxidant involves in biotic and abiotic stress has already been well described. Recent study indicates that it also participates in the detoxification of generated reactive oxygen species due to abiotic stresses. Thus, In order to study effects of salt stress and ascorbic acid on antioxidant enzyme activity, chlorophyll content, lipid peroxidation and abscisic acid accumulation of bean an experiment was conducted. The exogenous application of ascorbic acid in nutrition solution of bean plants indicated that later is involve in reduction of antioxidant enzyme activity and increase of resistance to salt stress. We observed that antioxidant enzyme activity increased due to salt stress and ascorbic acid via eliminating of reactive oxygen species decreased activities. Moreover, abscisic acid and lipid peroxidation were affected of salt stress. Increase of ascorbic acid concentration at 100 mM NaCl treatment prevented of lipid peroxidation and decreased generation of malondialdehyde as final product of peroxidation of membrane lipids. However, at high level of salinity, ascorbic acid did not significant effect on reduction of lipid peroxidation. Whereas, chlorophyll content decreased by reactive oxygen species. Ascorbic acid increased chlorophyll content at all of stressed and non-stressed treatments. Abscisic acid assay showed that, accumulation of this hormone increased under salt stress treatments and raise of ascorbic acid concentration in nutrition solution of stressed plants prevented of abscisic acid accumulation. Our data provide strong support to the hypothesis that exogenous of ascorbic acid reduces the harmful effects of salinity and increases resistance to salinity in bean plant.

Ramin SALEH JOUNEGHANI

2009-11-01

264

Relevance of DNA repair pathways on ascorbic acid effects on Echerichia Coli K-12 cells  

International Nuclear Information System (INIS)

Inactivation kinetics were performed with repair proficient and deficient Escherichia coli K-12 cells treated with oxidized solutions of ascorbic acid. The repair pathways controlled by the recA and uvrA gene products are essential for cell survival to the treatment. However, SOS chromotest result indicates that the SOS functions are only induced at high and toxic concentrations of the drug. Moreover, single strand breaks in DNA from treated cells are detected, demonstrating genome damage promoted by oxidized solutions of ascorbate. (M.A.C.)

265

Polarographic study of mixed-ligand complexes of cadmium(II) with ascorbic acid and some amino acids  

International Nuclear Information System (INIS)

The polarographic reduction of cadmium(II) in the presence of ascorbic acid and some amino acids (glutamic acid, aspartic acid, serine, threonine and tryptophan) has been found to involve a two-electron, reversible and diffusion-controlled step. The stability constants for the mixed chelates have been computed. It is shown that steric and electrostatic effects are important apart from statistical considerations. (author)

266

Effects of continuous supplementations of ascorbic acid, aspirin, vitamin E and selenium on some haematological parameters and serum superoxide dismutase level in broiler chickens.  

Science.gov (United States)

1. This study was conducted using male broiler chickens to determine the effects of ascorbic acid, aspirin, ascorbic acid+aspirin, vitamin E+selenium and ascorbic acid+aspirin+vitamin E+selenium supplementations on haematological parameters and serum superoxide dismutase concentration. 2. One hundred and twenty day-old male Hubbunt broiler chicks were randomly divided into 6 experimental groups of 20 chicks each and placed in different pens. Groups 2, 3, 4, 5 and 6 were given a diet supplemented with ascorbic acid, aspirin (in water), ascorbic acid+aspirin, vitamin E+selenium and ascorbic acid+aspirin+vitamin E+selenium, respectively for 45 d while group 1 was given a commercial broiler diet. 3. There was no significant effect of ascorbic acid, aspirin, ascorbic acid+aspirin, vitamin E+selenium supplementations on any of the haematological parameters (red blood cell, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin concentration, mean corpuscular haemoglobin) in broilers but ascorbic acid+aspirin+vitamin E+selenium supplementation significantly decreased the white blood cell counts. 4. In addition to this, ascorbic acid, aspirin, ascorbic acid+aspirin and ascorbic acid+aspirin+vitamin E+selenium supplementations had no significant effect on the serum superoxide dismutase level, but vitamin E+selenium supplementation increased the serum superoxide dismutase level. PMID:11201449

Tra?, B; Inal, F; Ba?, A L; Altunok, V; Elmas, M; Yazar, E

2000-12-01

267

Norepinephrine-modified glassy carbon electrode for the simultaneous determination of ascorbic acid and uric acid  

Energy Technology Data Exchange (ETDEWEB)

The oxidation of norepinephrine (NE) on a preactivated glassy carbon electrode leads to the formation of a deposited layer of about 4.2 x 10{sup -10} mol cm{sup -2} at the surface of the electrode. The electron transfer rate constant, k {sub s}, and charge transfer coefficient, {alpha}, for electron transfer between the electrode and immobilized NE film were calculated as 44 s{sup -1} and 0.46, respectively. The NE-modified glassy carbon electrode exhibited good electrocatalytic properties towards ascorbic acid (AA) oxidation in phosphate buffer (pH 7.0) with an overpotential of about 475 mV lower than that of the bare electrode. The electrocatalytic response was evaluated by cyclic voltammetry, chronoamperometry, amperometry and rotating disk voltammetry. The overall number of electrons involved in the catalytic oxidation of AA and the number of electrons involved in the rate-determining step are 2 and 1, respectively. The rate constant for the catalytic oxidation of AA was evaluated by RDE voltammetry and an average value of k {sub h} was found to be 8.42 x 10{sup 3} M{sup -1} s{sup -1}. Amperometric determination of AA in stirred solution exhibits a linear range of 2.0-1300.0 {mu}M (correlation coefficient 0.9999) and a detection limit of 0.076 {mu}M. The precision of amperometry was found to be 1.9% for replicate determination of a 49.0 {mu}M solution of AA (n = 6). In differential pulse voltammetric measurements, the NE-modified glassy carbon electrode can separate the AA and uric acid (UA) signals. Ascorbic acid oxidizes at more negative potential than UA. Also, the simultaneous determination of UA and AA is achieved at the NE-modified electrode.

Zare, H.R. [Department of Chemistry, Yazd University, P.O. Box 89195-741, Yazd (Iran, Islamic Republic of)]. E-mail: hrzare@yazduni.ac.ir; Memarzadeh, F. [Department of Chemistry, Yazd University, P.O. Box 89195-741, Yazd (Iran, Islamic Republic of); Ardakani, M. Mazloum [Department of Chemistry, Yazd University, P.O. Box 89195-741, Yazd (Iran, Islamic Republic of); Namazian, M. [Department of Chemistry, Yazd University, P.O. Box 89195-741, Yazd (Iran, Islamic Republic of); Golabi, S.M. [Electroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2005-05-30

268

Comparison of radioprotective effects of caffeine and ascorbic acid in male mice  

International Nuclear Information System (INIS)

The oxygen effect in radiation biology is well known. Since oxygen enhances radiation-induced biological damage, antioxidants should be radioprotectors. Ascorbic acid (vitamin C) or caffeine is an essential component in the diet of humans and a small range of other mammals. Radioprotective effects of vitamin C have been demonstrated in certain cells and animals, which would result from scavenging free radicals. Caffeine is the main psychoactive ingredient of coffee, tea, even coke with a high frequency of concurrent use in humans. Caffeine has been recently reported as a scavenger of hydroxyl radical in millimolar levels and a potently radioprotector in a chronically exposed rodent. This study investigates functional radioprotection of caffeine and ascorbic acid against gamma irradiation in male mice. Eight-week-old male C57BL/6N mice were irradiated with 6.5 Gy. A caffeine treated group was administered with 80 mg/kg body weight by i.p injection, a single exposure 1 hour before irradiation. Ascorbic acid was administered 330 mg/liter in drinking water through all the experimental period. The remaining mice were kept as sham controls. After collecting a serum from the experimental mice 6 hr after irradiation, qualitative analysis of testosterone was performed by means of radioimmunoassay (RIA). For histological investigation, testes were removed 1 week after irradiation and fixed in NBF. Fixed testes were processed for paraffin sections and stained by H-E. The circulan sections and stained by H-E. The circulating testosterone significantly decreased in all irradiated groups. The harmful effect of radiation on the body and organ weight and the appearance of semiferous tubules were significantly improved in the caffeine - or ascorbic acid-treated group. In conclusion, caffeine and ascorbic acid protected spermatogenesis from impairment against gamma radiation, acting as a radioprotector

269

Comparison of radioprotective effects of caffeine and ascorbic acid in male mice  

Energy Technology Data Exchange (ETDEWEB)

The oxygen effect in radiation biology is well known. Since oxygen enhances radiation-induced biological damage, antioxidants should be radioprotectors. Ascorbic acid (vitamin C) or caffeine is an essential component in the diet of humans and a small range of other mammals. Radioprotective effects of vitamin C have been demonstrated in certain cells and animals, which would result from scavenging free radicals. Caffeine is the main psychoactive ingredient of coffee, tea, even coke with a high frequency of concurrent use in humans. Caffeine has been recently reported as a scavenger of hydroxyl radical in millimolar levels and a potently radioprotector in a chronically exposed rodent. This study investigates functional radioprotection of caffeine and ascorbic acid against gamma irradiation in male mice. Eight-week-old male C57BL/6N mice were irradiated with 6.5 Gy. A caffeine treated group was administered with 80 mg/kg body weight by i.p injection, a single exposure 1 hour before irradiation. Ascorbic acid was administered 330 mg/liter in drinking water through all the experimental period. The remaining mice were kept as sham controls. After collecting a serum from the experimental mice 6 hr after irradiation, qualitative analysis of testosterone was performed by means of radioimmunoassay (RIA). For histological investigation, testes were removed 1 week after irradiation and fixed in NBF. Fixed testes were processed for paraffin sections and stained by H-E. The circulating testosterone significantly decreased in all irradiated groups. The harmful effect of radiation on the body and organ weight and the appearance of semiferous tubules were significantly improved in the caffeine - or ascorbic acid-treated group. In conclusion, caffeine and ascorbic acid protected spermatogenesis from impairment against gamma radiation, acting as a radioprotector.

Kim, Jin Kyu; Kim, Ji Hyang; Lee, Byoung Hun [KAERI, Taejon (Korea, Republic of); Yoon, Yong Dal [Hanyang Univ., Seoul (Korea, Republic of)

2003-04-01

270

Gender difference following high cholesterol diet induced renal injury and the protective role of rutin and ascorbic acid combination in Wistar albino rats  

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Full Text Available Abstract Background An increased interest is given to the impact of high fat diet on health worldwide. Abnormalities in lipid metabolism induced by high cholesterol diet (HCD were reported to exacerbate renal diseases via oxidative stress pathways. Rutin and ascorbic acid showed a protective role against oxidative stress-mediated diseases. Furthermore, both lipid metabolism and tissue response to oxidative stress damage was found to vary according to animal gender. Thus, the objective of this work was to examine possible gender-related differences and the possible protective effects of rutin and ascorbic acid supplementation on high cholesterol diet induced nephrotoxicity. Methods 96 young male and female Wistar albino rats were used. HCD supplemented animals were treated with rutin alone or in combination with ascorbic acid for 6 weeks. Creatinine plasma level was estimated. Furthermore, kidney levels of nucleic acids, total protein, malondialdehyde (MDA, reduced glutathione (GSH, total cholesterol, and triglycerides were determined. Finally, kidney tissues were used for histopathological examination. Results HCD supplementation decreased kidney level of nucleic acids, which was more prominent in female animals. Both vitamin combination significantly attenuated HCD induced decrease in nucleic acids. Moreover, kidney level of MDA was significantly altered by HCD in both genders, which was inhibited by rutin and ascorbic acid alone or in combination in male groups and by both vitamins in female groups. There was a reduction in kidney level of GSH by HCD, especially in male groups, which was attenuated by rutin and ascorbic acid combination. Kidney levels of total cholesterol and triglycerides were significantly increased by HCD supplementation in both genders. Coadministration with rutin and/or ascorbic acid protected from such increase, which was more obvious in both vitamins combination. Histopathological investigation supported vitamins protective effect, which was more prominent in male vitamins combination group. Conclusions HCD-induced renal injury in female was higher than in male animals, suggesting a better anti-oxidative stress defense response in male's kidney. Moreover, the antioxidant and reno-protective effects of rutin and ascorbic acid were augmented following their combination.

Al-Rejaie Salim

2012-03-01

271

Oxidation of ascorbic acid by a (salen)ruthenium(vi) nitrido complex in aqueous solution.  

Science.gov (United States)

The oxidation of ascorbic acid (H2A) by [Ru(VI)(N)(L)(MeOH)](+) in aqueous acidic solutions has the following stoichiometry: 2[Ru(VI)(N)] + 3H2A ? 2[Ru(III)(NH2-HA)](+) + A. Mechanisms involving HAT/N-rebound at low pH (?2) and nucleophilic attack at the nitride at high pH (?5) are proposed. PMID:25372447

Wang, Qian; Man, Wai-Lun; Lam, William W Y; Lau, Tai-Chu

2014-12-25

272

Ascorbic Acid Contents From Some Exotic Tree Species Growing in Rajasthan Desert  

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Full Text Available Ascorbic acid contents of stems, leaves and fruits from four selected exotic tree species like Colophospermummopane, Holoptelea integrifolia, Kigelia pinnata and Putranjiva roxburghii have been analysed. Maximumascorbic acid contents were found in the fruits of Colophospermum mopane (42.10mg/100g.d.w. while, minimumin the stems of Kigelia plnnata (22.15mg/100g.d.w.

B.B.S. Kapoor* and Shelja Pandita

2013-09-01

273

A Combination of Pre- and Post-Exposure Ascorbic Acid Rescues Mice from Radiation-Induced Lethal Gastrointestinal Damage  

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Full Text Available The development of an effective therapy for radiation-induced gastrointestinal damage is important, because it is currently a major complication of treatment and there are few effective therapies available. Although we have recently demonstrated that pretreatment with ascorbic acid attenuates lethal gastrointestinal damage in irradiated mice, more than half of mice eventually died, thus indicating that better approach was needed. We then investigated a more effective therapy for radiation-induced gastrointestinal damage. Mice receiving abdominal radiation at 13 Gy were orally administered ascorbic acid (250 mg/kg/day for three days before radiation (pretreatment, one shot of engulfment (250 mg/kg at 8 h before radiation, or were administered the agent for seven days after radiation (post-treatment. None of the control mice survived the abdominal radiation at 13 Gy due to severe gastrointestinal damage (without bone marrow damage. Neither pretreatment with ascorbic acid (20% survival, engulfment (20%, nor post-treatment (0% was effective in irradiated mice. However, combination therapy using ascorbic acid, including pretreatment, engulfment and post-treatment, rescued all of the mice from lethal abdominal radiation, and was accompanied by remarkable improvements in the gastrointestinal damage (100% survival. Omitting post-treatment from the combination therapy with ascorbic acid markedly reduced the mouse survival (20% survival, suggesting the importance of post-treatment with ascorbic acid. Combination therapy with ascorbic acid may be a potent therapeutic tool for radiation-induced gastrointestinal damage.

Yukihiro Takahashi

2013-09-01

274

The Effect of ascorbic acid injection into lateral ventricle on spatial learning and memory on adult male rats  

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Full Text Available Introduction: Ascorbic acid (AA acts as an antioxidant in the Central nervous system (CNS of the mammalians. It is released from the some nerve ending together with neurotransmitters. The results have shown that Ascorbic acid could affect learning as well as memory. In this study, we examined the effect of ICV injection of ascorbic acid on learning and memory by Morris water maze. Method: In the present study, 42 adult male rats weighing 250-300 g were used. then cannula implanted bilaterally in LV (AP=-0.8, LA=±1.5, DV=3.4.After recovery period, the animals were divided into 6 groups including; control group(no injected, 4 groups as experimental groups (received different doses of ascorbic acid 25, 50, 100, 150 mg/kg, 5th group as Sham-operated group (received normal saline as vehicle. Injection period has taken five consecutive days. 30 min after each injection they were trained in Morris Water Maze (MWM. Spatial learning and memory parameters recorded and then were analyzed. Results: These results showed that ICV injection of ascorbic acid decreased learning and spatial memory in rats. Ascorbic acid (100 mg/kg significantly decreased learning and spatial memory. Conclusion: It can be concluded that ascorbic acid decreased learning and spatial memory, directly or indirectly through interference to the neurotransmitters effects.

mehdi abbasnejad

2008-11-01

275

Role of ascorbic acid and ? tocopherol in alleviating salinity stress on flax plant (Linum usitatissimum L.  

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Full Text Available Salinity is one of the environmental challenges in the world affecting on several physiological processes and the most limiting factor of plant productivity and quality. Two pot experiments were conducted at the wire house of National Research Centre, Cairo, Egypt during two successive seasons of 2010/2011 and 2011/2012 to assess the efficiency of two antioxidant vitamins (ascorbic acid at 1.13 and 2.27 mM or ? tocopherol at 0.46 and 0.93 mM and/or salinity stress at (0.0, 3.08, 6.16, 9.23 ds/m on photosynthetic pigments, protein, carbohydrate, minerals, oil contents and yield as well as fatty acids composition of the yielded oils of three flax cultivars (Sakha 3, Giza 8 and Ariane. The data revealed that salinity stress caused significant and gradual decreases in total photosynthetic pigments, polysaccharides, total carbohydrates, total proteins and the uptake of Mg, K, Ca and P in the leaves of three flax cultivars with increasing salinity levels (3.08, 6.16, 9.23 ds/m. Otherwise, significant and gradual increase appeared in both Na and Cl. Ascorbic acid and ? tocopherol at different concentrations caused significant increases in photosynthetic pigments, total carbohydrates and protein contents in the leaves of flax plants irrigated either with tap water or saline solution as compared with their corresponding controls. Exogenous application of ascorbic and ? tocopherol at different concentrations exhibited decreases in Na and Cl whereas increases appeared in Mg, K, Ca and P relative to their corresponding control. Ascorbic acid (1.13 and 2.27 mM and ? tocopherol (0.46 and 0.93 mM caused marked increases in yield and yield attributes of three flax cultivars either in plants irrigated with tap water or saline solution as compared to corresponding control. Ascorbic acid effects were more pronounced than ? tocopherol effects. In addition, the higher level of two vitamins was more pronounced than the lower level. Regarding plants irrigated with tap water, it was noted that ascorbic acid at 2.27 mM caused significant increase in oil content by 19.75 % in Giza 8 whereas ? tocopherpl at 0.93 mM caused significant increase by 14.83% in Sakha 3 and 13.70% in Ariane. Regarding plants irrigated with saline solution (9.23 ds/m, it was found that ? tocopherol at 0.93 mM caused significant increase in oil % by 30.84 %, 9.66 % and 35.62 % in Sakha 3, Giza 8 and Ariane cv. respectively. Responses of three flax cultivars to salt stress were more or less similar; since salinity stress caused marked increases in total saturated fatty acids accompanied by decreases in total unsaturated fatty acids as salinity levels increased. Myristic acid (C14:0 and oleic acid (C18:1 were the most affected saturated and unsaturated fatty acids in response to different salinity levels. The effect of ascorbic acid at 2.27 mM and tocopherol at 0.93 mM were found to be contrary to that of salinity as marked increases appeared in unsaturated fatty acids as compared with control plants. It could be concluded that foliar application of ascorbic acid and ? tocopherol could play an enhancement role and alleviate the harmful effect of salinity stress on many metabolic and physiological processes of three flax cultivars that reflected in increasing seed yield quality and quantity.

Mervat Sh. Sadak

2014-03-01

276

Ascorbic Acid and ?-Tocopherol Minimize Salt-Induced Wheat Leaf Senescence  

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Full Text Available BackgroundLeaf senescence is an oxidative process, and most of the catabolic events involved in senescence are propagated irreversibly once initiated. ResultsSalinity hastened the senescence of wheat flag leaves, decreased the concentrations of chlorophyll, total carotenoids, ascorbic acid, total phenol, calcium, potassium, magnesium, K+/Na+ ratio and soluble proteins, as well as the activities of catalase and peroxidase. Conversely, salinity increased sodium, chloride, and the chlorophylla:b ratio, as well as membrane permeability, hydrogen peroxide, and malondialdehyde synthesis. Both antioxidants application reduced the hydrogen peroxide accumulation, lipid peroxidation, membrane permeability, sodium and chloride content over control plants. The antioxidants enzyme activities were significantly increased by antioxidant spray. Enhanced accumulation of ascorbate, phenol, carotenoids, calcium, potassium and magnesium was seen in antioxidants-sprayed plants compared with control plants at 65 days after sowing. Under moderate and sever salinity levels application of both antioxidants alleviated the harmful effects of salinity on leaf senescence related parameter. The higher levels of antioxidants and low level of H2O2 in flag leaf may be the prerequisite for delayed leaf senescence in antioxidants-sprayed plants. ConclusionsIt can be concluded that ascorbic acid-sprayed plants can postpone the leaf senescence by peroxide/phenolic/ascorbate system which is involved in scavenging the ROS produced during leaf senescence.

Farouk S.

2011-09-01

277

Serum ascorbic acid concentration in patients with acute Falciparum malaria infection: possible significance  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Falciparum malaria infection is associated with significant destruction of erythrocytes. This leads to the release of toxic metabolic products, including oxidant compounds.We measured the serum concentration of the antioxidant, ascorbic acid, in 129 patients presenting with acute falciparum malaria [...] infection and in 65 healthy individuals. None of the study subjects administered any form of ascorbic acid supplementation within one week prior to participation in this study. The mean serum ascorbate concentration in infected adult males (n = 49, age range 18-50 years) was found to be 2.02 ± 0.20 mg/dL, and it was 2.03 ± 0.24 mg/dL in infected adult females (n = 56, age range 18-50 years). These values were significantly greater than the serum ascorbate levels (1.54 ± 0.10 mg/dL) in healthy adult males (n = 28) and females (n = 28) (p

Garba Ibrahim, Hassan; Ubom, Gregory; Haruna, Maryam.

278

The electrochemical synthesis of polyaniline/polysulfone composite films and electrocatalytic activity for ascorbic acid oxidation  

Energy Technology Data Exchange (ETDEWEB)

Polyaniline (PANI)/polysulfone (PSF) composite films with asymmetric porous structure were successfully prepared by electropolymerization. The back face (in contact with the electrode) of the freestanding composite film is green while the outer face is white. The chemical component and the morphology of the surfaces were characterized by FTIR spectra and scanning electron microscopy, respectively. It was shown that replicate films gave reproducible voltammetry in 0.5 M H{sub 2}SO{sub 4}. The influence of the electrolyte and the acidic concentration on the redox peak currents of polyaniline were investigated in detail. The composite film electrode showed good electrocatalytic activity for ascorbic acid, which the anodic overpotential was evidently reduced compared with that obtained at bare Pt electrode. The diffusion coefficient of ascorbic acid was 1.38 x 10{sup -6} cm{sup 2} s{sup -1}.

Hu Zhongai [Key Laboratory of Polymer, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)]. E-mail: Zhongai@nwnu.edu.cn; Shang Xiuli [Key Laboratory of Polymer, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Yang Yuying [Key Laboratory of Polymer, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Kong Chao [Key Laboratory of Polymer, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Wu Hongying [Key Laboratory of Polymer, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

2006-04-10

279

Ascorbic-acid-assisted recovery of cobalt and lithium from spent Li-ion batteries  

Science.gov (United States)

Recycling of the major components from spent Li-ion batteries (LIBs) is considered desirable to prevent environmental pollution and recycle valuable metals. The present work investigates a novel process for recovering Co and Li from the cathode materials (containing LiCoO2 and Al) by a combination of ultrasonic washing, calcination, and organic acid leaching. Copper can also be recovered from the anode materials after they are manually separated from the cathode. Ascorbic acid is chosen as both leaching reagent and reducing agent to improve the Co recovery efficiency. Leaching efficiencies as high as 94.8% for Co and 98.5% for Li are achieved with a 1.25 mol L-1 ascorbic acid solution, leaching temperature of 70 °C, leaching time of 20 min, and solid-to-liquid ratio of 25 gL-1. The acid leaching reaction mechanism has been preliminarily studied based on the structure of ascorbic acid. This method is shown to offer an efficient way to recycle valuable materials from spent LIBs, and it can be scaled up for commercial application.

Li, Li; Lu, Jun; Ren, Yang; Zhang, Xiao Xiao; Chen, Ren Jie; Wu, Feng; Amine, Khalil

2012-11-01

280

Study of radio-protective effects of ascorbic acid in rates  

International Nuclear Information System (INIS)

The aim of this study was to evaluate the potential radio-protective effects of different ascorbic acid concentrations (vitamin C) in rats before whole body irradiation with total dose of 7 Gy (60Co source) using two different dose rates of 1 and 0.55 Gy.min-1 by increasing percent of surviving. In the first group (1 Gy/m); rats were administered four different concentrations of ascorbic acid (7.5, 12.5, 100, 200 mg/kg b wt ) in drinking water for 30 days before irradiation starting from the ablactation which considered as day 0. Whereas, in the second group (0.55 Gy/m); rats were administered six different concentrations of ascorbic acid (1, 5, 7.5, 12.5, 100, 200 mg/kg b wt) before irradiation with total dose 7 Gy (60Co source). The results have showed that the ascorbic acid enhance the 30-day survival of irradiated rats in 1 and 0.55 Gy/m groups, compared to the control group. The mean cumulated probability of survival of rats (1 Gy/m group) was 66%± 6 (Mean± S.E), 69%± 5, 52%± 9 and 51%± 9 in groups of rats which administered 7.5, 12.5, 100, 200 mg/kg, respectively, versus 41%± 9 in control group for 14 days. While, it was 90%± 2, 90%± 2, 88%± 2, 94%± 1, 84%± 3 and 78%± 3 in groups of rats which administered 1, 5, 7.5, 12.5, 100, 200 mg/kg respectively, versus 52%± 6 in control group for 30 days. Our data, also, indicated that all ascorbic acid concentrations in both groups had significant reduction in mortality and increasing percent of surviving compared to the control groups. We conclude that all ascorbic acid concentrations which used in both groups (1 and 0.55 Gy/m), had radioprotective effects in rats when administrated before irradiations, and this role was more effective against lower dose rate of radiation exposure. (author)

 
 
 
 
281

Determination of uric acid in the presence of ascorbic acid with hexacyanoferrate lanthanum film modified electrode  

International Nuclear Information System (INIS)

A glassy carbon electrode modified with LaHCF was constructed and was characterized by cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). The resulting LaHCF modified glassy carbon electrode had a good catalytic character on uric acid (UA) and was used to detect uric acid and ascorbic acid (AA) simultaneously. This modified electrode exhibits potent and persistent electron-mediating behavior followed by well-separated oxidation peaks towards UA and AA with activation overpotential. For UA and AA in mixture, one can well separate from the other with a potential large enough to allow the determination of one in presence of the other. The DPV peak currents obtained increased linearly on the UA in the range of 2.0 x 10-7 to 1.0 x 10-4 mol/L with the detection limit (signal-to-noise ratio was 3) for UA 1.0 x 10-7 mol/L. The proposed method showed excellent selectivity and stability, and the determination of UA and AA simultaneously in urine was satisfactory

282

Determination of uric acid in the presence of ascorbic acid with hexacyanoferrate lanthanum film modified electrode  

Energy Technology Data Exchange (ETDEWEB)

A glassy carbon electrode modified with LaHCF was constructed and was characterized by cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). The resulting LaHCF modified glassy carbon electrode had a good catalytic character on uric acid (UA) and was used to detect uric acid and ascorbic acid (AA) simultaneously. This modified electrode exhibits potent and persistent electron-mediating behavior followed by well-separated oxidation peaks towards UA and AA with activation overpotential. For UA and AA in mixture, one can well separate from the other with a potential large enough to allow the determination of one in presence of the other. The DPV peak currents obtained increased linearly on the UA in the range of 2.0 x 10{sup -7} to 1.0 x 10{sup -4} mol/L with the detection limit (signal-to-noise ratio was 3) for UA 1.0 x 10{sup -7} mol/L. The proposed method showed excellent selectivity and stability, and the determination of UA and AA simultaneously in urine was satisfactory.

Wang Guangfeng; Meng Jian; Liu Hongying; Jiao Shoufeng; Zhang Wei; Chen Daolei [College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Anhui Key Laboratory of Chemo-Biosensing, Wuhu 241000 (China); Fang Bin [College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Anhui Key Laboratory of Chemo-Biosensing, Wuhu 241000 (China)], E-mail: wangyusandra@yahoo.com.cn

2008-02-15

283

Effect of combination treatment of gamma irradiation and ascorbic acid on physicochemical and microbial quality of minimally processed eggplant (Solanum melongena L.)  

Science.gov (United States)

Gamma irradiation alone and in combination with ascorbic acid was tested for preventing the surface browning and maintaining the quality attributes of minimally processed eggplant. Eggplant samples after preparation were subjected to treatment of gamma irradiation in the dose range of 0.25-1.0 kGy and to combination treatments of ascorbic acid dip at a concentration of 2.0% w/v and gamma irradiation (dose range 0.5-2.0 kGy) followed by storage at 3±1 °C, RH 80%. Studies revealed inverse correlation (r=-0.93) between the polyphenol oxidase (PPO) activity, browning index and the treatments of ascorbic acid and gamma irradiation. Combinatory treatment of 2.0% w/v ascorbic acid and 1.0 kGy gamma irradiation proved to be significantly (p?0.05) effective in inhibiting the PPO activity, preventing the surface browning and maintaining the creamy white color and other quality attributes of minimally processed eggplant up to 6 days of refrigerated storage. Sensory evaluation revealed that control and 0.25 kGy irradiated samples were unacceptable only after 3 days of storage. Samples irradiated at 0.5 kGy and 0.75 kGy were unacceptable after 6 days of storage. Microbial analysis revealed that radiation processing of minimally processed eggplant at 1.0 kGy with and without ascorbic acid resulted in around 1 and 1.5 log reduction in yeast and mold count as well as bacterial count just after treatment and 6 days of storage therefore, enhances the microbial safety.

Hussain, Peerzada R.; Omeera, A.; Suradkar, Prashant P.; Dar, Mohd A.

2014-10-01

284

Evidence for the in vivo formation of ascorbic acid 2-O-alpha-glucoside in guinea pigs and rats.  

Science.gov (United States)

In vivo formation of ascorbic acid 2-O-alpha-glucoside (AA-2G) in guinea pigs and rats given ascorbic acid (AA) orally in combination with maltose was examined. A metabolite of AA which has the same HPLC retention characteristics as authentic AA-2G was detected in the blood, urine and liver of guinea pigs 1-2 hr after their administration. The metabolite was isolated from the urine by chromatographic procedures and identified as AA-2G by its UV spectrum, non-reducibility, susceptibility to alpha-glucosidase hydrolysis, HPLC profile and elementary analysis. The same glucoside was also synthesized by rats and found in the urine, although it could not be determined qualitatively in the blood. AA-2G-forming activities of tissue homogenates from both animals were apparently correlated with their alpha-glucosidase activities and, moreover, both activities were completely inhibited by a specific neutral alpha-glucosidase inhibitor. Thus, we conclude that AA-2G is a possible metabolite produced by enzymatic alpha-glucosidation after a combined administration of AA and maltose to guinea pigs and rats. PMID:1859466

Muto, N; Ban, Y; Akiba, M; Yamamoto, I

1991-07-15

285

Routine sample preparation and HPLC analysis for ascorbic acid (vitamin C) determination in wheat plants and Arabidopsis leaf tissues.  

Science.gov (United States)

Plants have developed various mechanisms to protect themselves against oxidative stress. One of the most important non-enzymatic antioxidants is ascorbic acid. There is thus a need for a rapid, sensitive method for the analysis of the reduced and oxidised forms of ascorbic acid in crop plants. In this paper a simple, economic, selective, precise and stable HPLC method is presented for the detection of ascorbate in plant tissue. The sensitivity, the short retention time and the simple isocratic elution mean that the method is suitable for the routine quantification of ascorbate in a high daily sample number. The method has been found to be better than previously reported methods, because of the use of an economical, readily available mobile phase, UV detection and the lack of complicated extraction procedures. The method has been tested on Arabidopsis plants with different ascorbate levels and on wheat plants during Cd stress. PMID:24873913

Szalai, Gabriella; Janda, T; Pál, Magda

2014-06-01

286

Mutagenicity of Acridine and Ascorbic Acid in Rhizobia of Legume Trees  

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Full Text Available The present study aimed to induce a great variation existing among Rhizobium spp. that nodulate Leucaena leucocephala and Sesbania sesban, through the treatment with acridine and ascorbic acid and selection of isolates for efficiency in the symbiotic association. Bacteria were isolated from nodules of both hosts growing in Egyptian soil, subcultured, and verified to be rhizobia. The isolates varied significantly in their resistance to antibiotics and NaCl, their growth on different carbohydrates, and their effect on the pH of culture media. Most isolates showed intermediate antibiotic resistance, the capacity to use numerous carbohydrates, and a neutral to acid pH response. The mean generation time of these isolates ranged from 4.813 to 6.437 and 4.600 to 6.523 for Sesbania sesban and Leucaena leucocephala, respectively. Both acridine orange and ascorbic acid had genotoxic hazards on all rhizobial strains examined here. They demonstrated a dose-response for decreasing cell survival at the levels that are not excessively toxic to bacteria. The standard assay with pre-incubation was quite toxic to the bacteria than plate incorporation test. Acridine orange and ascorbic acid shows an increase in number of auxotrophic mutants over the spontaneous value which is evidence for their mutagenicity caused by DNA damage. The biochemical mutants obtained in this study were identified using nine plates of minimal medium, each supplemented with different combinations of four growth factors. From the results reported here, it can be concluded that acridine mutagenesis is due to an enhancement of mismatch repair. In addition, ascorbic acid may be mutagenic and cytotoxic through the generation of hydrogen peroxide.

M.A. Nassef

2002-01-01

287

Effect of Acridine and Ascorbic Acid on Rhizobia of Legume Trees  

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Full Text Available The present study aimed to induce a great variation exists among Rhizobium spp. that nodulate Leucaena leucocephala and Sesbania sesban, through the treatment with acridine and ascorbic acid and selection of strains for efficiency of the symbiotic association appears possible. Bacteria were isolated from nodules of both hosts growing in Egyptian soil, subcultured, and verified to be rhizobia. The isolates varied significantly in their resistance to antibiotics and NaCl, their growth on different carbohydrate sources, and their effect on the pH of culture media. Most isolates showed intermediate antibiotic resistance, the capacity to use numerous carbohydrates, and a neutral to acid pH response. The mean generation times of these isolates ranged from 4.813 to 6.437 and 4.600 to 6.523 for Sesbania sesban and Leucaena leucocephala, respectively. Both acridine orange and ascorbic acid appeared genotoxic hazards effect on all rhizobial strains examined here. They demonstrated a dose-response for decreasing cell survival at the levels that are not excessively toxic to the bacteria. The standard assay with pre-incubation was quite toxic to the bacteria than plate incorporation test. Acridine orange and ascorbic acid shows an increase in the number of auxotrophic mutants over the spontaneous value this is evidence for their mutagenicity caused by DNA damage. The biochemical mutants obtained in this study were identified using nine plates of minimal medium each was supplemented with different combinations of four growth factors. From the results reported here, it can be concluded that acridine mutagenesis is due to an enhancement of mismatch repair. In addition, ascorbic acid may be mutagenic and cytotoxic through the generation of hydrogen peroxide.

El-Adl

2001-01-01

288

Kinetics of ascorbic acid loss during hot water blanching of fluted pumpkin (Telfairia occidentalis) leaves.  

Science.gov (United States)

The kinetics of thermal degradation of ascorbic acid in fluted pumpkin leaves were investigated from 60 to 90°C (pH 5.0 to 6.5). Ascorbic acid degradation was modeled as a first order rate reaction with the rate constants increasing with increase in pH of the medium. The pH and temperature dependence of the rates of destruction gave highly significant correlations when analyzed by the thermal resistance and activated complex reaction rate methods. Activation energy (Ea) ranged from 41.2 to 18.2 kJ/mol while D-values ranged from 103.3 to 22.4 min. The changes in activation energy affected Ko values which ranged from 5.98?×?10(4) to 41.7 min(-1). PMID:23572770

Ariahu, Charles C; Abashi, Diana K; Chinma, Chiemela Enyinnaya

2011-08-01

289

Electrooxidation of ascorbic acid on polyaniline and its implications to fuel cells  

Science.gov (United States)

L-Ascorbic acid (AA) has been shown to undergo oxidation on polyaniline (PANI) without a platinum-group catalyst. A direct ascorbic acid fuel cell (DAAFC) has been assembled by employing an anode coated with PANI catalyst. From the experimental studies using cyclic voltammetry, amperometry and IR spectroscopy, it has been concluded that PANI facilitates the oxidation of AA. It has been possible to achieve a maximum power density of 4.3 mW cm -2 at a load current density of 15 mA cm -2 at 70 °C. As both AA and PANI are inexpensive and environmental-friendly, the present findings are expected to be useful for the development of cost-effective DAAFCs for several low power applications.

Mondal, S. K.; Raman, R. K.; Shukla, A. K.; Munichandraiah, N.

290

Influence of osmotic dehydration on ascorbic acid loss in pickled dry peppers (Capsicum chinense)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The objective of this work was (1) to develop a dehydrated pepper with 45% humidity, determining the drying curves for pepper, with and without osmotic pre-treatment and (2) to evaluate the influence of both drying and osmotic treatment on the content ascorbic acid (vitamin C) in fresh pepper and pe [...] pper with 45% humidity. The experiments were carried out using the peppers cut in half, with and without osmotic pre-treatment, followed by drying in an oven at 70 ºC. The results showed that the osmotic pretreatment did not influence the retention of ascorbic acid during the drying of pepper. The sensory analysis regarding the color, flavor, and texture attributes revealed that there was no difference in the acceptability.

Tissiane Mayara da, Silva; Eliana Janet Sanjinez, Argandoña; Grasiele Scaramal, Madrona; Izabel Cristina Freitas, Moraes; Charles Windson Isidoro, Haminiuk; Ivanise Guilherme, Branco.

2012-10-01

291

Influence of osmotic dehydration on ascorbic acid loss in pickled dry peppers (Capsicum chinense)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The objective of this work was (1) to develop a dehydrated pepper with 45% humidity, determining the drying curves for pepper, with and without osmotic pre-treatment and (2) to evaluate the influence of both drying and osmotic treatment on the content ascorbic acid (vitamin C) in fresh pepper and pe [...] pper with 45% humidity. The experiments were carried out using the peppers cut in half, with and without osmotic pre-treatment, followed by drying in an oven at 70 ºC. The results showed that the osmotic pretreatment did not influence the retention of ascorbic acid during the drying of pepper. The sensory analysis regarding the color, flavor, and texture attributes revealed that there was no difference in the acceptability.

Tissiane Mayara da, Silva; Eliana Janet Sanjinez, Argandoña; Grasiele Scaramal, Madrona; Izabel Cristina Freitas, Moraes; Charles Windson Isidoro, Haminiuk; Ivanise Guilherme, Branco.

292

Stability studies of ascorbic acid 2-glucoside in cosmetic lotion using surface response methodology.  

Science.gov (United States)

Ascorbic acid 2-glucoside (AA-2G) has been widely used in cream and lotion types of cosmetic products. Thus, the degradation of AA-2G caused by the temperature change and pH variation was very critical for determining the bio-functionality of cosmetics. Response surface methodology (RSM) was introduced to study the influence of temperature and pH on the stability of AA-2G. The optimal condition of retaining AA-2G with the highest stability was determined to be 55.3°C and pH 6.4. The antioxidative activities of AA-2G including DPPH and ABTS free radical scavenging activities, metal chelating activity, and reducing ability were also determined. AA-2G was a good ascorbic acid derivative which could be used in cosmetic products as an active ingredient. PMID:23416010

Huang, Wen-Ying; Lee, Pei-Chi; Huang, Ling-Kuei; Lu, Li-Ping; Liao, Wayne C

2013-03-15

293

A Flexible Ascorbic Acid Fuel Cell with a Microchannel Fabricated using MEMS Techniques  

Science.gov (United States)

We fabricated a miniature ascorbic acid fuel cells equipped with a microchannel for the circulation of ascorbic acid (AA) solution using micro electronic mechanical system techniques. The fuel cell was fabricated on a flexible polyimide substrate, and its porous carbon-coated aluminium (Al) electrodes of 2.8 mm in width and 11 mm in length were formed using photolithography and screen-printing techniques. The porous carbon was deposited by screen-printing of carbon-black ink on the Al electrode surfaces in order to increase the effective electrode surface area and to absorb more enzymes on the cathode surface. The microchannel with a depth of 200 ?m was fabricated using a hot-embossing technique. A maximum power of 0.60 ?W at 0.58 V that corresponds to a power density of 1.83 ?W/cm2 was realized by introducing a 200 mM concentrated AA solution at room temperature.

Mogi, Hiroshi; Fukushi, Yudai; Koide, Syohei; Sano, Ryohei; Sasaki, Tsubasa; Nishioka, Yasushiro

2013-12-01

294

Electrochemically oxidized carbon anode in direct L-ascorbic acid fuel cells  

Energy Technology Data Exchange (ETDEWEB)

The activity of electrochemically oxidized carbon electrode was investigated in the operation of a direct L-ascorbic acid fuel cell anode. The surface oxygen species placed on electrochemically oxidized carbon electrode were analyzed by X-ray photoelectron spectroscopy and cyclic voltammetry. The electrochemical oxidation process of carbon electrode can facilitate the pore-filling process (i.e., wetting) of the electrolyte into the microstructure of the carbon electrode by increasing the number of more polar functional groups on the electrode surface. The electrochemically oxidized carbon electrode exhibited significantly enhanced electro-catalytic oxidation activity of L-ascorbic acid compared to an unmodified carbon electrode. Moreover, the simplified electrode structure using carbon paper without an additional powder-based precious catalyst layer is very favorable in creating percolation network and generates power density of 18 mW/cm{sup 2} at 60 C. (author)

Uhm, Sunghyun [Department of Chemical Engineering, Inha University, Incheon 402-751 (Korea); Department of Environmental Science and Engineering, GIST, Gwangju 500-712 (Korea); Choi, Jinsub [Nanomaterials Application Division, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea); Chung, Sung Taik [Department of Chemical Engineering, Inha University, Incheon 402-751 (Korea); Lee, Jaeyoung [Department of Environmental Science and Engineering, GIST, Gwangju 500-712 (Korea)

2007-12-31

295

Methemoglobinemia due to application of prilocaine during circumcision and the effect of ascorbic acid.  

Science.gov (United States)

Local anesthesia with prilocaine has become a routine part of ambulatory circumcision procedures. Methemoglobinemia is a rare but potentially lethal complication of local anesthetics. We report the case of a 42-day-old boy who presented with cyanosis after receiving local anesthesia with prilocaine. Methemoglobin level revealed severe methemoglobinemia (methemoglobin=44.5%). His cyanosis promptly resolved after intravenous administration of ascorbic acid. Cases of local anesthetic-induced methemoglobinemia in urology are under recognized. Although the association between prilocaine use and methemoglobinemia has generally restricted prilocaine use in infants, it is still widely used in ambulatory procedures, especially during circumcision in the neonatal period. Prilocaine should not be used in infants less than 3 months of age because of the risk of methemoglobinemia and alternative local analgesics should be considered among this age group. We also discuss the use of ascorbic acid during treatment in light of the literature. PMID:19013416

Boran, Perran; Tokuc, Gulnur; Yegin, Zeliha

2008-12-01

296

SIMULTANEOUS ELECTROCHEMICAL DETECTION OF DOPAMINE, ASCORBIC ACID AND URIC ACID USING COPPER-PHTHALOCYANINE FUNCTIONALIZED MWCNTS  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Multiwalled carbon nanotububes functionalized with amino groups (MWCNT-NH2) and further modified with copper-phthalocyaninetetrasulphonate (4ß(SO3) CuPc) were used for preparing a hybrid electrode [MWCNT-NH2/4ß(SO3)CuPc/GC] using glassy carbon (GC) as a support. This hybrid electrode was tested for [...] the detection of dopamine (DA) in the presence of ascorbic acid (AA) and uric acid (UA) in a PBS buffer solution at pH 6.8. The presence of the macrocyclic increased the resolution of the oxidation signals of AA, DA and UA into three very well distinct oxidation peaks. This effect was enhanced when the complex is adsorbed on multiwalled carbon nanotubes. In addition, the hybrid films provide a simple method for selective detection of DA, AA and UA in biological samples. The calibration curves for DA were obtained over the range of 1x10-6-1x10-3M, obtaining a good selectivity and sensitivity.

MAMIE, SANCY; J, FRANCISCO SILVA; JORGE, PAVEZ; JOSÉ H, ZAGAL.

297

SIMULTANEOUS ELECTROCHEMICAL DETECTION OF DOPAMINE, ASCORBIC ACID AND URIC ACID USING COPPER-PHTHALOCYANINE FUNCTIONALIZED MWCNTS  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Multiwalled carbon nanotububes functionalized with amino groups (MWCNT-NH2) and further modified with copper-phthalocyaninetetrasulphonate (4ß(SO3) CuPc) were used for preparing a hybrid electrode [MWCNT-NH2/4ß(SO3)CuPc/GC] using glassy carbon (GC) as a support. This hybrid electrode was tested for [...] the detection of dopamine (DA) in the presence of ascorbic acid (AA) and uric acid (UA) in a PBS buffer solution at pH 6.8. The presence of the macrocyclic increased the resolution of the oxidation signals of AA, DA and UA into three very well distinct oxidation peaks. This effect was enhanced when the complex is adsorbed on multiwalled carbon nanotubes. In addition, the hybrid films provide a simple method for selective detection of DA, AA and UA in biological samples. The calibration curves for DA were obtained over the range of 1x10-6-1x10-3M, obtaining a good selectivity and sensitivity.

MAMIE, SANCY; J, FRANCISCO SILVA; JORGE, PAVEZ; JOSÉ H, ZAGAL.

2117-21-01

298

IMPACT OF EXTRACELLULAR CALCIUM ALONG WITH ASCORBIC ACID ON CELLULAR REACTIVATION AND INSULIN SECRETION IN DIABETIC MIN6 CELLS  

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Full Text Available Diabetes is not a single disease but characterized by a group of syndromes. Oxidative stress and defects in insulin secretory pathway are the major problems associated with type 2 diabetes. Extracellular Ca2+ influx is the major trigger which stimulates insulin secretion in pancreatic β cells. In this study we combined the most common antioxidant ascorbic acid with extracellular calcium to observe their cooperative effect on diabetic MIN6 cells. Our results demonstrated firstly the major role of ascorbic acid individually as well as with calcium in cell viability as compared to individual calcium supplementation. Secondly, the combined concentration of ascorbic acid and calcium leads to maximum increase in insulin level in dose dependent manner upto 5mM ascorbic acid and decrease beyond this concentration.

Archana Tiwari

2012-01-01

299

Changes in Ascorbic Acid Content, Antioxidant Capacity and Sensory Quality of Fresh-cut Mangosteens During Storage  

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Full Text Available Fresh-cut mangosteens, stored in modified atmosphere packaging (MAP; 5% O2 + 9% CO2, in vacuum packaging (VAC and in air (AIR were examined for ascorbic acid content, antioxidant capacity and sensory quality during 14 days of storage at 4oC. After 4 days-storage, fresh-cut fruits with MAP resulted in better retention of ascorbic acid and antioxidant capacity than those stored in AIR throughout the storage. Furthermore, there were no significant differences in ascorbic acid contents between fruits stored in MAP and VAC, as well as antioxidant capacities, during the remaining period of storage. Fresh-cut fruits with MAP treatment obtained the highest sensory scores, compared with other treatments, throughout the entire period of storage. Fresh-cut mangosteens stored in MAP resulted in the best overall retention of ascorbic acid, antioxidant capacity and sensory quality.

Supranee MANURAKCHINAKORN

2004-06-01

300

Transgenic potato overproducing L-ascorbic acid resisted an increase in methylglyoxal under salinity stress via maintaining higher reduced glutathione level and glyoxalase enzyme activity.  

Science.gov (United States)

Salt-tolerance was studied in transgenic potato. It was conferred by overexpression of ascorbate pathway enzyme (D-galacturonic acid reductase, GalUR). As genetic engineering of the GalUR gene in potato enhances its ascorbic acid content (L-AsA), and subsequently plants suffered minimal oxidative stress-induced damage, we now report on the comprehensive aptness of this engineering approach for enhanced salt tolerance in transgenic potato (Solanum tuberosum L. cv. Taedong Valley). Potatoes overexpressing GalUR grew and tuberized in continuous presence of 200 mM of NaCl. The transgenic plants maintained a higher reduced to oxidized glutathione (GSH:GSSG) ratio together with enhanced activity of glutathione dependent antioxidative and glyoxalase enzymes under salinity stress. The transgenics resisted an increase in methylglyoxal that increased radically in untransformed control plants under salinity stress. This is the first report of genetic engineering of ascorbate pathway gene in maintaining higher level of GSH homeostasis along with higher glyoxalase activity inhibiting the accumulation in methylglyoxal (a potent cytotoxic compound) under salt stress. These results suggested the engineering of ascorbate pathway enzymes as a major step towards developing salinity tolerant crop plants. PMID:21750996

Upadhyaya, Chandrama Prakash; Venkatesh, Jelli; Gururani, Mayank Anand; Asnin, Leonid; Sharma, Kavita; Ajappala, Hemavathi; Park, Se Won

2011-11-01

 
 
 
 
301

Capparidaceous Medicinal Plants of North-West Rajasthan: Good Sources of Ascorbic Acid  

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Full Text Available Ascorbic acid contents of roots, shoots and fruits of three selected medicinal plants like Capparis decidua,Cleome gynandra and Cleome viscosa of family Capparidaceae have been analysed. Maximum ascorbicacid contents were found in the fruits of Capparis decidua (108.12mg/100g.d.w. while, minimum in theroots of Cleome viscosa (62.25mg/100g.d.w.

B.B.S. Kapoor* and Raksha Mishra

2013-06-01

302

Role of ascorbic acid supplement in reducing oxidative stress and hepatotoxicity in lead intoxication  

International Nuclear Information System (INIS)

Objective: The present study was conducted to measure the oxidative stress and hepatotoxicity in lead intoxicated sprague dawley rats with and without supplementation of ascorbic acid. Study Design: Randomized Control Trial. Place of Study: Physiology Department, Army Medical College, Rawalpindi. (From Oct 2007 to Sep 2008) Material and Methods: One hundred and five male rats (age, 90-120 days; weight 200 - 250 gm) were divided into three groups each having 35 rats. Rats of group 1 and group 2 were given weekly injections of sodium acetate (10 mg /kg body weight) and lead acetate (10 mg /kg body weight) respectively, whereas rats of group 3 were administered lead acetate(10 mg /kg body weight) through weekly injections and ascorbic acid in drinking water (500 mg/l). After 6 weeks, 4 ml of blood was drawn from each rat by cardiac puncture. The blood was allowed to clot and serum was separated for estimation of serum malondialdehyde (MDA) levels on spectrophotometer; and serum alanine aminotransferase (ALT) levels and aspartate aminotransferase (AST) levels on Merck Micorlab 200. Results: Lead intoxication of rats revealed that serum MDA levels were raised to 7.8 +- 0.48 micro mol/l (control, 3.2 +-0.39 micro mol/l), ALT levels to 76.26 +- 5.88 IU/l (control, 44.1 +- 3.26) and AST levels to 258.06 +- 13.30 IU/l (control, 156.2 +- 4.97). Ascorbic acid supplementation significantly lowered serum MDA levels (3.8 +- 0.34 micro mol/l), ALT levels (52.26 +-4.57 IU/l) and AST ), ALT levels (52.26 +-4.57 IU/l) and AST levels (188.13 +- 12.91 IU/l). Conclusion: Ascorbic acid supplementation ameliorates lead intoxication probably by reducing the oxidative stress, thus preventing the development of hepatotoxicity, but this amelioration is not equal to the control. (author)

303

Reductive release of Fe(III) from bovine lactoferrin by ascorbic acid  

International Nuclear Information System (INIS)

The kinetics of the reduction of Fe/sup 3+/ from bovine diferric Lactoferrin (Fe/sub 2/Lf) and monoferric C-terminal (Fe/sub C/-Lf) and N-terminal (Lf-Fe/sub N/) sites is investigated at ph 6.1 and 3.5 under pseudo first-order conditions using ascorbic acid (AA) as a biological reducing agent and 1, 10-Ortho phenanthroline (O-phen) as Fe/sup 2+/ chelator. Pseudo first-order rate constants as a function of ascorbic acid concentration are measured. Second order rate constants (k2) for Fe/sub 2/Lf, Lf-Fe/sub N/, Fe/sub C/-Lf at ph 6.1 and 27 deg. C are 0.1527 M/sup -1/.min/sup -1/, 0.0381 M/sup -1/.min-1, 0.1381 M/sup -1/.min/sup -1/, respectively. While, at ph 3.5 and 27 deg. C these values are 0.1915 M/sup -1/.min-1, 0.1116 M/sup -1/.min/sup -1/, 0.4434 M/sup -/.min/sup -1/, respectively. A linear dependence of k/sub obs/ on ascorbic acid concentration is suggestive of simple pseudo first-order pathway for reduction of iron under the conditions applied for all the three forms of protein. Moreover, the results show that the C-terminal site is more labile toward reduction by ascorbic acid than the N-terminal site. (author)

304

Effect of ascorbic acid on food preference and consumption in captive capybaras (Hydrochoerus hydrochaeris)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O ácido ascórbico é um nutriente essencial para as capivaras (Hydrochoerus hydrochaeris). No presente trabalho foi avaliado o efeito do ácido ascórbico sobre o consume e as preferências alimentares a curto e longo prazo, assim como a influencia da escolha sobre a sintomatologia da carência de vitami [...] na C na dieta. Não foram observadas diferencias no consumo de alimento na ausência deste nutriente. Considerando as preferências a longo prazo (24h), os animais acostumados a consumir vitamina C continuavam consumindo preferencialmente o alimento suplementado. As preferências alimentares em capivaras não parecem depender da disponibilidade de ácido ascórbico; no entanto, quando acostumados à vitamina C, estes animais podem reconhecer e selecionar o ácido ascórbico na alimentação subseqüente. São discutidos os mecanismos que permitem as capivaras "avaliar" a qualidade nutricional do alimento, assim como o valor adaptativo destes comportamentos em populações silvestres. Abstract in english The aim of this work was to study the short and long term influences of ascorbic acid on Hydrochoerus hydrochaeris, if supplemented in their food. No differences regarding food intake were observed in the absence of vitamin C. On a daily basis, animals accustomed to food containing ascorbic acid pre [...] fered to continue eating the same food. Food preference in capybaras did not seem to depend on ascorbic acid availability; however, when accustomed to vitamin C, capybaras might recognize and select ascorbic acid in subsequent food. Mechanisms allowing capybaras to "evaluate" the nutritional quality of their food are discussed, as well as the adaptive value of this behavior in free ranging populations.

Martín Roberto, Alvarez; Fernando Osvaldo, Kravetz.

2009-06-01

305

Spectroscopic investigation of the interaction between {beta}-cyclodextrin and ascorbic acid  

Energy Technology Data Exchange (ETDEWEB)

Inclusion compound of vitamin C (ascorbic acid) with {beta}-cyclodextrin ({beta}-CD), prepared by different methods (kneading, co-precipitation and freeze-drying) has been caracterized by several spectroscopic techniques (FTIR, {sup 1}H NMR, UV-Vis), powder X-ray diffraction and DSC technique. Based on the chemical shifts observed in the {sup 1}H-NMR and on FTIR spectra the tentative conclusion is that vitamin C probably enters the cyclodextrin torus forming the inclusion complex.

Bratu, Ioan; Kacso, Irina [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Muresan-Pop, Marieta [Babes-Bolyai University, Faculty of Physics, 1 Mihail Kogalniceanu 400084 Cluj-Napoca (Romania); Farcas, Sorin I, E-mail: ioan.bratu@itim-cj.r

2009-08-01

306

Iron-rich drinking water and ascorbic acid supplementation improved hemolytic anemia in experimental Wistar rats.  

Science.gov (United States)

Abstract Anemia is a frequent problem in both the primary and secondary health care programs. In contrast, most areas of northeast India are vulnerable to iron toxicity. In the present study, we documented the effect of administration of iron rich water on hemolytic anemia in a Wistar rats' animal model. Hemolytic anemia was induced by phenyl hydrazine through intraperitoneal route and diagnosed by the lowering of blood hemoglobin. After inducing the hemolytic anemia, 24 Wistar rats (n?=?6 in four groups) were randomly assigned to 1?mg/l, 5?mg/l, and 10?mg/l ferric oxide iron along with 1?mg/ml ascorbic acid administered through drinking water; a control group was treated with iron-free water. The hematological and biochemical parameters, iron levels in liver, spleen, and kidney were estimated after 30?d of treatment. In the group treated with 5?mg/l iron and ascorbic acid, a significant increase of serum iron and ferritin, and a decrease of TIBC (total iron binding capacity) were observed without changes in other biochemical parameters and histopathological findings. However, in the group treated with 10?mg/l iron and ascorbic acid, hematological changes with significantly higher values for white blood cell count, serum glutamic phospho transaminase, serum glutamic oxaloacetic transaminase, alkaline phosphatase, glucose, splenic, and liver iron content, indicate potential toxicity at this supplementation level. Data suggest that the optimum concentration of iron (5?mg/l) and ascorbic acid solution may improve anemic conditions and may be therapeutically beneficial in the treatment of iron deficiency anemia without any negative impact, while 10?mg/l in drinking water seems to be the threshold for the initiation of toxicity. PMID:24896300

Chaturvedi, Richa; Chattopadhyay, Pronobesh; Banerjee, Saumen; Bhattacharjee, Chira R; Raul, Prasanta; Borah, Kusum; Singh, Lokendra; Veer, Vijay

2014-11-01

307

Low-energy electron collisions with gas-phase ascorbic acid molecule  

Energy Technology Data Exchange (ETDEWEB)

We report on the results of total electron scattering cross-section for ascorbic acid molecule. In the energy dependence of scattering cross-section the resonance features at the energies 0.25, 0.78, 1.76, 3.5 eV were obtained. We discuss the connection between the resonances found in our cross-section and the features observed in the dissociative electron attachment experiments.

Chernyshova, I V; Kontros, J E; Shpenik, O B, E-mail: an@zvl.iep.uzhgorod.u [Institute of Electron Physics, Ukrainian Academy of Sciences, 21 Universitetska, 88017 Uzhgorod (Ukraine)

2009-11-01

308

Effect of Salicylic Acid and Ascorbic Acid on Germination Indexes and Enzyme Activity of Sorghum Seeds under Drought Stress  

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Seed priming methods have been used to increase germination characteristics under stress conditions. The effects of drought stress (0, -4, -8, -12 and -16 bar) and salicylic acid 25 ppm at 15 °C for 15 h and ascorbic acid 25 ppm at 15 °C for 15 h on germination percentage, germination index, means time to germination, normal seedling percentage and enzyme activity were assessed in the laboratory for sorghum seeds (Sorghum bicolor L.). Results showed that th...

Tabatabaei S. A.

2013-01-01

309

Comparison of complexing properties of ascorbic and 5,6-0-isopropylideneascorbic acids in aqueous and aqueous-organic solutions  

International Nuclear Information System (INIS)

By the pH-potentiometric method estimated are stability constants of calcium (2), cobalt (2), nickel (2), zink (2), vanadium (4) with ascorbic and 5.6-0-isopropylidene-ascorbic acids in aqueous and aqueous-organic solutions and it is shown that they do not practically depend on the ligand nature. On this basis confirmed is the conclusion about the absence of complex formation in the region of a side circuit of ascorbic acid. Using the spectrophotometric method it is shown that hydrolytic decomposition of metal ascorbinates in aqueous-organic solutions takes place considerably slower than in aqueous ones

310

Effects of ascorbic acid and oxalic acid on uptake and translocation of zinc in maize (Zea Mays L.) using 65Zn radiotracer  

International Nuclear Information System (INIS)

This study was done to evaluate the effect of oxalic and ascorbic acids on 65Zn uptake and translocation in Maize plants through solution culture experiment so that the desired acid remains available in the roots zone

311

Study of ascorbic acid interaction with hydroxypropyl-beta-cyclodextrin and triethanolamine, separately and in combination.  

Science.gov (United States)

Complexation between ascorbic acid, hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and triethanolamine (TEA), separately and in combination, was studied in solution and solid state. The freeze-drying method was used to prepare solid complexes, while physical mixtures being obtained by simple blending. These complexes were characterized in the solid state using differential scanning calorimetry (DSC) and infrared spectroscopy (IR). Nuclear magnetic resonance spectroscopy ((1)H and (13)C NMR) was used in aqueous solutions to obtain information about the mode of interaction. The degradation rate of each complex in solution was determined, and the stability constant of the complexes and the degradation rate of the ascorbic acid within the complexes were obtained. NMR studies provided clear evidence of partial inclusion into the HP-beta-CD cavity, but the stability constant value was very small indicating a weak host-guest interaction. The influence of complexation on the degradation rate of ascorbic acid was evaluated, and the data obtained showed a pronounced enhancement of aqueous stability with the TEA association complex, while this effect was lower with the HP-beta-CD inclusion complex. NMR experiments showed evidence of the formation of aggregates. PMID:17851014

Garnero, Claudia; Longhi, Marcela

2007-11-30

312

Effect of the Electric Field Frequency on Ascorbic Acid Degradation during Thermal Treatment by Ohmic Heating  

Science.gov (United States)

In this work, the influence of the electric field frequency and solids content on the degradation kinetics of ascorbic acid during ohmic heating of acerola pulp and acerola serum was investigated. The degradation percentage of ascorbic acid in the pulp after 120 min of heating varied between 12 and 17%. For the serum, the degradation percentage was in the range of 13 and 18%. The results were fitted to the first-order model, and the kinetic rate constants ranged from 1.1 to 1.6 × 10?3 min?1 and from 1.1 to 1.5 × 10?3 min?1 for pulp and serum, respectively. D values ranged between 1480 and 2145 min for the pulp and between 1524 and 1951 min for the serum. A distinct behavior between the kinetic parameters of the pulp and serum in electric field frequencies ranging from 10 to 1000 Hz indicates that the presence of distinct amounts and types of solids might affect the rate of the electron transfer in electrochemical reactions. These variables may also affect the polarization process stimulated by the oscillating electric field. The non-achievement of the equilibrium of the polarization process may have an influence on oxidation reactions, affecting the predisposition to hydrogen donation from the ascorbic acid molecule. PMID:24892902

Mercali, Giovana Domeneghini; Schwartz, Steven; Marczak, Ligia Damasceno Ferreira; Tessaro, Isabel Cristina; Sastry, Sudhir

2014-01-01

313

Validation of ascorbic acid tablets of national production by igh-performance liquid chromatography method  

International Nuclear Information System (INIS)

We validate an analytical method by high-performance liquid chromatography to determine ascorbic acid proportion in vitamin C tablets, which was designed as an alternative method to quality control and to follow-up of active principle chemical stability, since official techniques to quality control of ascorbic acid in tablets are not selective with degradation products. Method was modified according to that reported in USP 28, 2005 for analysis of injectable product. We used a RP-18 column of 250 x 4.6 mm 5 ?m with a UV detector to 245 nm. Its validation was necessary for both objectives, considering parameters required for methods of I and II categories. This method was enough linear, exact, and precise in the rank of 100-300 ?g/mL. Also, it was selective with remaining components of matrix and with the possible degradation products achieved in stressing conditions. Detection and quantification limits were estimated. When method was validated it was applied to ascorbic acid quantification in two batches of expired tablets and we detected a marked influence of container in active degradation principle after 12 months at room temperature. (Author)

314

Radiation protective effects of cysteamine and glutathione on four nucleobases and ascorbic acid in aqueous solution  

International Nuclear Information System (INIS)

This paper shows the radiation protective effects of cysteamine and glutathione (reduced form) on the ?-systems of four nucleobases in aqueous solution. Thymine, cytosine, adenine, and guanine solutions containing cysteamine (or glutathione) in various concentrations were irradiated with gamma-rays from a 0.22 PBq Co-60 source. The residual concentration of each nucleobase after irradiation was measured by spectrophotometry and liquid chromatography. The ?-systems of cytosine and adenine were protected and repaired by adding about a 3-6 fold excess of cysteamine in relative to the cytosine and the adenine concentration. Each amino group, cytosine and adenine, plays an important role for the protection of their own ?-system from the radiation damage. The ?-system of thymine was protected from the radiation damage, but was not repaired by cysteamine. The protective effects of cysteamine on guanine were saturated with increasing the cysteamine concentration. Ascorbic acid solutions containing cysteamine were irradiated also. The radiation protective effect of cysteamine on ascorbic acid was small. A first approximation analysis was made on the radiation protective effects. The autooxidation of ascorbic acid in aqueous solution containing several kinds of antioxidants was measured and analyzed. (author)

315

Seasonal profiles of leaf ascorbic acid content and redox state in ozone-sensitive wildflowers  

International Nuclear Information System (INIS)

Cutleaf coneflower (Rudbeckia laciniata L.), crown-beard (Verbesina occidentalis Walt.), and tall milkweed (Asclepias exaltata L.) are wildflower species native to Great Smoky Mountains National Park (U.S.A.). Natural populations of each species were analyzed for leaf ascorbic acid (AA) and dehydroascorbic acid (DHA) to assess the role of ascorbate in protecting the plants from ozone stress. Tall milkweed contained greater quantities of AA (7-10 ?mol g-1 fresh weight) than crown-beard (2-4 ?mol g-1 fresh weight) or cutleaf coneflower (0.5-2 ?mol g-1 fresh weight). DHA was elevated in crown-beard and cutleaf coneflower relative to tall milkweed suggesting a diminished capacity for converting DHA into AA. Tall milkweed accumulated AA in the leaf apoplast (30-100 nmol g-1 fresh weight) with individuals expressing ozone foliar injury symptoms late in the season having less apoplast AA. In contrast, AA was not present in the leaf apoplast of either crown-beard or cutleaf coneflower. Unidentified antioxidant compounds were present in the leaf apoplast of all three species. Overall, distinct differences in antioxidant metabolism were found in the wildflower species that corresponded with differences in ozone sensitivity. - Wildflower species exhibit differences in ascorbic acid content and redox status that affect ozone sensitivity

316

Influence of refrigeration length and of sugar addition on ascorbic acid content in some natural juices  

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Full Text Available Following some studies concerning the main factors influencing the concentration of vitamins within food raw materials, especially ascorbic acid, this work tries to evidence the influence of the refrigeration temperature and of the sucrose addition on content of this vitamin in three types of natural juice. The biological material was represented by orange, strawberry and kivi natural juices, obtained from these fruits by means a crushing out process. For each type of juice there were made up samples without addition and samples with 5% and 10% sucrose addition. The ascorbic acid determination was carried out from fresh juice as well as from juice kept in refrigerator, at certain time intervals (24, 48, 96 ?i 168 hours. The storage of these juices under refrigeration conditions has determined percentage reductions of vit. C content of these ones. Thus, after 168 hours of storage, in the three types of analysed juices the highest loss of vitamin have been registrated in samples without sucrose addition, and the least ones in samples with 10% addition. The comparison of vitamin C values in the three analysed juices, subjected 168 hours to refrigeration process, has evidenced that the highest loss of ascorbic acid have been in orange juice, and the least one in kiwi juice. Keywords: vitamin C, sucrose, orange, strawberry, kiwi

Liviu Fartaies

2009-06-01

317

Determination of Proximate Composition, Ascorbic Acid and Heavy Metal Content of African Walnut (Tetracarpidium conophorum  

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Full Text Available The proximate composition, ascorbic acid and heavy metal content of (African walnut Tetracarpidium conophorum were evaluated using chemical analysis. The result of the proximate composition showed the following; moisture (48.70%, carbohydrate (53.20%, crude protein (35.22%, crude fat (6.21%, crude fiber (3.34% and ash (2.03%.It also contained 53.50mg/100ml of ascorbic acid. The heavy metal concentrations in the fruit is Fe (0.064ppm, Mn (0.012ppm, Cr (0.001ppm, Ni (0.005ppm while the concentrations of Hg, Pb and Cd were not detected. The results revealed that the T. conophorum is rich in ascorbic acid and carbohydrate with moderate valves of crude protein while the ash content was shown to be very low. This result shows that T. conophorum nut is not polluted with heavy metals since the concentrations of the heavy metals were all below WHO permissible limits. This nut is therefore shown to be safe for public consumption.

Edem

2009-01-01

318

THE INFLUENCE OF ASCORBIC ACID ON DEVELOPMENT OF ADENOCARCINOMA MAMMAE IN MICES  

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Full Text Available The influence of great dosage of ascorbic acid during the experimental induction of adenocarcinoma mammae was experimented. For the experiments the female of CBA/H mice were used. The animals were divided into two groups: the control (K and experimental (I, II, III group. The mice of the control group were given 0.5 ml physiological solution, and the mice of experimental subgroup I were given 10, and of the subgroup II were given 100, and of subgroup III were given 1.000 mg of ascorbic acid/d. In the beginning of experiment all animals of both control and experimental group were given 5x10 6 of live cells of adenocarcinoma mammae. During and in the end of the experiment the changes in the body weight, weigth of adenocarcinoma mammae, and weigth o spleen was examined. The achieved results exemplify that the aplication of high doses of ascorbic acid, in the case of CBA/H mice, decreased the weight of mice, decreased the weight of adenocacinoma mammae, decreased the mass and celularity of spleen, and decreased stimulates the number of leucocytes.

Zoran Pavlovi?

2004-07-01

319

Voltammetric Behavior and Amperometric Determination of Ascorbic Acid at Cadmium Pentacyanonitrosylferrate Film Modified GC Electrode  

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Full Text Available The present work, describes electrochemical preparation of a novel cadmium pentacyanonitrosylferrate (CdPCNF film as a Prussian Blue analogous on the glassy carbon (GC electrode from a solution of 5 mM CdCl2 and 5 mM Na2[Fe(CN5NO]. The effect of experimental conditions such as pH and composition of electrodeposition solution on the peak current of the modified electrode and its stability were investigated. In the optimized conditions a controllable and repeatable value of CdPCNF film was obtained. The modified GC electrode showed a reversible cyclic voltammograms due to the redox reaction of Fe(III / Fe(II in the film. The CdPCNF film showed a good electrocatalytic activity toward the oxidation of ascorbic acid. The mean value of rate constant k and the diffusion coefficient of ascorbic acid in the solution D, were found to be 3.6 ´ 102 M-1 s-1, and 4.4 ´ 10-6 cm2 s-1 respectively. A calibration graph was obtained over concentration of 5 – 50 µM. The limit of detection was found to be 2.52 µM by hydrodynamic amperometry. This technique was used to the selective determination of ascorbic acid in the pharmaceutical preparations and fruit juices.

H. Razmi and M. Harasi

2008-01-01

320

IMPROVEMENT OF SALT TOLERANCE IN DURUM WHEAT BY ASCORBIC ACID APPLICATION  

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Full Text Available The main objective of this study is to examine whether exogenously applied Ascorbic acid (AsA may enhance the salt tolerance in durum wheat (Triticum durum Desf. var. Waha. Two weeks old seedling, grown in plastic pots of 1kg, were subjected to salt stress by adding 25ml of NaCl (150mm, and treated or not with the addition of ascorbic acid (0.7 mM. Two weeks after salt stress, plants were harvested and the various measures were recorded.The effects of salt stress, in the presence and absence of vitamin C, on the leaf growth, leaf area (LA and some physiological and biochemical changes were investigated. It was established that the application of vitamin C mitigate to variable extent the adverse effect of salt stress on plant growth, may be due, in part, to increased leaf area, improved chlorophyll and carotenoid contents, enhanced proline accumulation and decreased H2O2 content.In conclusion, we can say that treatment with ascorbic acid improve salt tolerance in durum wheat through the enhancement of multiple processes.

Fercha Azzedine

2011-03-01

 
 
 
 
321

Radioprotection potential of the ascorbic acid on the carrageenan used as food additive  

International Nuclear Information System (INIS)

Carrageenans are a group of natural carbohydrates that are present in the structure of certain varieties of red algae (Rhodophyceae). They are used in emulsions, for syneresis control and to grow up, to promote adhesiveness and dispersion. In the industry of foods they can be used for instance, as thickness and gelling agents, alone or together with other additives. The processing of foods by radiation is increasing considerably, because the efficiency of the process in the industrial decontamination of products. The objective of this work was to study the action of the ascorbic acid as potential radioprotector of the carrageenan against 60 Co gamma radiation effects, using the viscosity as parameter. Samples of commercial carrageenan dissolved at 1,0% were irradiated in the presence or not of ascorbic acid, with doses of 0.0 kGy; 1.0 kGy; 2.5 kGy; 5.0 kGy and 10.0 kGy. After the irradiation the relationships viscosity/dose were established for the temperature of 60 deg C. For the dose of 10.0 kGy a better protecting effect of the ascorbic acid on the carrageenan was seen. The implications of the use of this antioxidant is discussed as a form of minimizing the effect of the radiation in irradiated foods. (author)

322

Genotoxicity and oxidative stress of microwave radiation role of ascorbic acid  

International Nuclear Information System (INIS)

Radiofrequency fields and especially microwaves are very important part of electromagnetic spectrum that can produce generations of reactive oxygen species, and thus can affect DNA and cause chromosomal aberrations. So this effect can be diminished by the supplement of an antioxidant such as ascorbic acid. In this study, the proposed protective role of ascorbic acid was tested against the EMF induced chromosomal aberrations and lipid peroxidation. The present study proved that EMF had a clastogenic effect on the bone marrow cells of mice, either with the exposure to EMF; 950 MHz or frequency EMF; 2450 MHz. This effect was evidenced by structural and numerical chromosomal aberrations. The study also proved that EMF had an effect on oxidative stress, evidenced by increase in the level of lipid peroxide, in a dose dependent manner. So, the mechanism of EMF induced chromosomal aberrations can be explained by this oxidative stress induced by EMF exposure. The present study showed that ascorbic acid had a protective effect against both EMF induced chromosomal aberrations and oxidative stress, when it is applied concomitantly with EMF exposure either at frequency of 950 MHz or 2450 MHz. this is evident by decreases in the level of lipid peroxide and decrease in chromosomal aberrations

323

Seasonal profiles of leaf ascorbic acid content and redox state in ozone-sensitive wildflowers  

Energy Technology Data Exchange (ETDEWEB)

Cutleaf coneflower (Rudbeckia laciniata L.), crown-beard (Verbesina occidentalis Walt.), and tall milkweed (Asclepias exaltata L.) are wildflower species native to Great Smoky Mountains National Park (U.S.A.). Natural populations of each species were analyzed for leaf ascorbic acid (AA) and dehydroascorbic acid (DHA) to assess the role of ascorbate in protecting the plants from ozone stress. Tall milkweed contained greater quantities of AA (7-10 {mu}mol g{sup -1} fresh weight) than crown-beard (2-4 {mu}mol g{sup -1} fresh weight) or cutleaf coneflower (0.5-2 {mu}mol g{sup -1} fresh weight). DHA was elevated in crown-beard and cutleaf coneflower relative to tall milkweed suggesting a diminished capacity for converting DHA into AA. Tall milkweed accumulated AA in the leaf apoplast (30-100 nmol g{sup -1} fresh weight) with individuals expressing ozone foliar injury symptoms late in the season having less apoplast AA. In contrast, AA was not present in the leaf apoplast of either crown-beard or cutleaf coneflower. Unidentified antioxidant compounds were present in the leaf apoplast of all three species. Overall, distinct differences in antioxidant metabolism were found in the wildflower species that corresponded with differences in ozone sensitivity. - Wildflower species exhibit differences in ascorbic acid content and redox status that affect ozone sensitivity.

Burkey, Kent O. [Plant Science Research Unit, USDA-ARS and North Carolina State University, 3127 Ligon Street, Raleigh, NC 27607 (United States)]. E-mail: koburkey@unity.ncsu.edu; Neufeld, Howard S. [Appalachian State University, Boone, NC (United States); Souza, Lara [Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN (United States); Chappelka, Arthur H. [Auburn University, Auburn, AL (United States); Davison, Alan W. [University of Newcastle, Newcastle, England (United Kingdom)

2006-10-15

324

Characterization of L-ascorbic acid single crystals grown from solution with different solvents  

Energy Technology Data Exchange (ETDEWEB)

Single crystals of L-ascorbic acid, popularly known as vitamin-C, were grown from solutions with different solvents and solvent combinations by low temperature solution growth methods. The suitability of different solvents and solvent combinations such as acetone, ethanol, methanol, isopropyl alcohol, water, water + acetone (1:1), water + ethanol (3:1), water + isopropyl alcohol (3:1) and isopropyl alcohol + methanol (1:1) for crystal growth of L-ascorbic acid was found out by assessing the solubility and crystallization behaviours. Solubility of L-ascorbic acid in selected solvents and solvent combinations in a range of temperatures was determined by gravimetric method. Solution prepared with water, water + acetone (1:1), water + ethanol (3:1) and water + isopropyl alcohol (3:1) were yielded crystals with tabular, columnar and prismatic habits and their morphologies were evaluated by goniometry. Grown single crystals were characterized with various instrumental techniques such as powder X-ray diffraction, Fourier infrared spectroscopy, optical transmittance study, differential scanning calorimetry and second harmonic generation studies. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Srinivasan, K.; Vanitha Devi, K. [Crystal Growth Laboratory, Department of Physics, School of Physical Sciences, Bharathiar University, Coimbatore-641 046, Tamil Nadu (India)

2010-09-15

325

Effect of the electric field frequency on ascorbic acid degradation during thermal treatment by ohmic heating.  

Science.gov (United States)

In this work, the influence of the electric field frequency and solids content on the degradation kinetics of ascorbic acid during ohmic heating of acerola pulp and acerola serum was investigated. The degradation percentage of ascorbic acid in the pulp after 120 min of heating varied between 12 and 17%. For the serum, the degradation percentage was in the range of 13 and 18%. The results were fitted to the first-order model, and the kinetic rate constants ranged from 1.1 to 1.6×10(-3) min(-1) and from 1.1 to 1.5×10(-3) min(-1) for pulp and serum, respectively. D values ranged between 1480 and 2145 min for the pulp and between 1524 and 1951 min for the serum. A distinct behavior between the kinetic parameters of the pulp and serum in electric field frequencies ranging from 10 to 1000 Hz indicates that the presence of distinct amounts and types of solids might affect the rate of the electron transfer in electrochemical reactions. These variables may also affect the polarization process stimulated by the oscillating electric field. The non-achievement of the equilibrium of the polarization process may have an influence on oxidation reactions, affecting the predisposition to hydrogen donation from the ascorbic acid molecule. PMID:24892902

Mercali, Giovana Domeneghini; Schwartz, Steven; Marczak, Ligia Damasceno Ferreira; Tessaro, Isabel Cristina; Sastry, Sudhir

2014-06-25

326

Ascorbic acid does not enhance hypoxia-induced vasodilation in healthy older men.  

Science.gov (United States)

In response to hypoxia, a net vasodilation occurs in the limb vasculature in young healthy humans and this is referred to as "hypoxia-induced vasodilation". We performed two separate experiments to determine (1) if hypoxia-induced forearm vasodilation is impaired in older men (n = 8) compared to young men (n = 7) and (2) if acute systemic infusion of ascorbic acid would enhance hypoxia-induced vasodilation in older men (n = 8). Heart rate, mean arterial pressure, oxygen saturation, minute ventilation, forearm vascular conductance (FVC, Doppler ultrasound), and cutaneous vascular conductance (CVC, laser Doppler flowmetry) were recorded continuously while subjects breathed 10% oxygen for 5 min. Changes from baseline were compared between groups and between treatments. The older adults had a significantly attenuated increase in FBF (13 ± 4 vs. 30 ± 7%) and FVC (16 ± 4 vs. 30 ± 7%) in response to 5 min of hypoxia. However, skin blood flow responses were comparable between groups (young: 35 ± 9, older: 30 ± 6%). In Experiment 2, FVC responses to 5 min of breathing 10% oxygen were not significantly different following saline (3 ± 10%) and ascorbic acid (8 ± 10%) in the older men. Ascorbic acid also had no physiological effects in the young men. These findings advance our basic understanding of how aging influences vascular responses to hypoxia and suggest that, in healthy humans, hypoxia-induced vasodilation is not restrained by reactive oxygen species. PMID:25052494

Pollock, Jonathan P; Patel, Hardikkumar M; Randolph, Brittney J; Heffernan, Matthew J; Leuenberger, Urs A; Muller, Matthew D

2014-07-01

327

Comparative Study of Ascorbic Acid and Tocopherol Concentrations in Hydroponic- and Soil-Grown Lettuces  

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Full Text Available Hydroponically-grown produce may be a way of helping to feed the world a variety of fruits and vegetables, regardless of soil quality, space availability or climate. The objective of this study was to determine whether hydroponicallygrown lettuce contains as much ascorbic acid and tocopherol as soil-grown lettuce. We analyzed four varieties of lettuce, including: Waldmann’s Dark Green, Red Lollo Antago, Red Romaine Annapolis, and Butterleaf. The tocopherol content of hydroponically-grown Waldmann’s Dark Green, Red Lollo Antago, and Red Romaine Annapolis was 229%, 497% and 492% higher, respectively, compared to their soil-grown counterpart. The ascorbic acid content of hydroponically-grown Waldmann’s Dark Green, Red Lollo Antago, and Red Romaine Annapolis was 93%, 171% and 216% higher, respectively, compared to their soil-grown counterparts. Hydroponically grown lettuce varieties are significantly higher in both ascorbic acid and tocopherol content than their soil-grown counterparts, and hydroponic gardening is a viable option for producing nutritious fruits and vegetables.

Drew N. Buchanan

2013-09-01

328

Niosomes of Ascorbic Acid and ?-Tocopherol in the Cerebral Ischemia-Reperfusion Model in Male Rats  

Science.gov (United States)

The objective of the present study was to prepare a stable iv injectable formulation of ascorbic acid and ?-tocopherol in preventing the cerebral ischemia. Different niosomal formulations were prepared by Span and Tween mixed with cholesterol. The physicochemical characteristics of niosomal formulations were evaluated in vitro. For in vivo evaluation, the rats were made ischemic by middle cerebral artery occlusion model for 30?min and the selected formulation was used for determining its neuroprotective effect against cerebral ischemia. Neuronal damage was evaluated by optical microscopy and transmission electron microscopy. The encapsulation efficiency of ascorbic acid was increased to more than 84% by remote loading method. The cholesterol content of the niosomes, the hydrophilicity potential of the encapsulated compounds, and the preparation method of niosomes were the main factors affecting the mean volume diameter of the prepared vesicles. High physical stability of the niosomes prepared from Span 40 and Span 60 was demonstrated due to negligible size change of vesicles during 6 months storage at 4–8°C. In vivo studies showed that ST60/Chol 35?:?35?:?30 niosomes had more neuroprotective effects against cerebral ischemic injuries in male rats than free ascorbic acid.

Varshosaz, Jaleh; Taymouri, Somayeh; Pardakhty, Abbas; Asadi-Shekaari, Majid; Babaee, Abodolreza

2014-01-01

329

Inhibition of cell proliferation and migration by oxidative stress from ascorbate-driven juglone redox cycling in human bladder-derived T24 cells  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer The cytotoxicity of juglone is markedly increased by ascorbate. Black-Right-Pointing-Pointer T24 cell death by oxidative stress is necrosis-like. Black-Right-Pointing-Pointer Redox cycling by juglone/ascorbate inhibits cell proliferation. Black-Right-Pointing-Pointer Cellular migration is impaired by juglone/ascorbate. -- Abstract: The effects of juglone on T24 cells were assessed in the presence and absence of ascorbate. The EC{sub 50} value for juglone at 24 h decreased from 28.5 {mu}M to 6.3 {mu}M in the presence of ascorbate. In juglone-treated cells, ascorbate increased ROS formation (4-fold) and depleted GSH (65%). N-acetylcysteine or catalase restricted the juglone/ascorbate-mediated effects, highlighting the role of oxidative stress in juglone cytotoxicity. Juglone alone or associated with ascorbate did not cause caspase-3 activation or PARP cleavage, suggesting necrosis-like cell death. DNA damage and the mild ER stress caused by juglone were both enhanced by ascorbate. In cells treated with juglone (1-5 {mu}M), a concentration-dependent decrease in cell proliferation was observed. Ascorbate did not impair cell proliferation but its association with juglone led to a clonogenic death state. The motility of ascorbate-treated cells was not affected. Juglone slightly restricted motility, but cells lost their ability to migrate most noticeably when treated with juglone plus ascorbate. We postulate that juglone kills cells by a necrosis-like mechanism inhibiting cell proliferation and the motility of T24 cells. These effects are enhanced in the presence of ascorbate.

Kviecinski, M.R., E-mail: mrkviecinski@hotmail.com [Laboratorio de Bioquimica Experimental, Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Pedrosa, R.C., E-mail: rozangelapedrosa@gmail.com [Laboratorio de Bioquimica Experimental, Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Felipe, K.B., E-mail: kakabettega@yahoo.com.br [Laboratorio de Bioquimica Experimental, Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Farias, M.S., E-mail: mirellesfarias@hotmail.com [Laboratorio de Bioquimica Experimental, Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis (Brazil); Glorieux, C., E-mail: christophe.glorieux@uclouvain.be [Toxicology and Cancer Biology Research Group, Louvain Drug Research Institute, Universite Catholique de Louvain, 73 Avenue E. Mounier, GTOX 7309, 1200 Brussels (Belgium); Valenzuela, M., E-mail: mavalenzuela@med.uchile.cl [Toxicology and Cancer Biology Research Group, Louvain Drug Research Institute, Universite Catholique de Louvain, 73 Avenue E. Mounier, GTOX 7309, 1200 Brussels (Belgium); Sid, B., E-mail: brice.sid@uclouvain.be [Toxicology and Cancer Biology Research Group, Louvain Drug Research Institute, Universite Catholique de Louvain, 73 Avenue E. Mounier, GTOX 7309, 1200 Brussels (Belgium); and others

2012-05-04

330

INFLUENCE OF ASCORBIC ACID ON SCLEROTIA PRODUCTION OF DESCENDANCE OF SOME CLAVICEPS PURPUREA HYBRID AND NON-HYBRID PARENTAL STRAINS  

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Full Text Available This paper includes the experimental results regarding the effects of ascorbic acid, present in culture media, on the phenotypisation of “sclerotia/ha production” character. The behaviour of descendance of some monoparental and hybrid strains of Claviceps purpurea is analysed; the obtained data evidenced variations of strain bioproductivity, under the influence of ascorbic acid, variations which can be correlated with strain origin, alkaloid type etc.

Maria+Magdalena Zamfirache

2006-08-01

331

Synthesis of l-Ascorbic Acid Lactone Derivatives.  

Science.gov (United States)

A small focused library which comprised of l-AA lactone derivatives was built with a facile method. This reported method was optimized by modifying the acidity of the solvent. As a result, 12 l-AA lactones were synthesized. Among these lactones, lactones 8-12 were new compounds. The cytotoxicity of these synthetic compounds were investigated. PMID:24955300

Shao, Li-Dong; Wu, Ya-Nan; Xu, Jun; He, Juan; Zhao, Yu; Peng, Li-Yan; Li, Yan; Yang, Yu-Rong; Xia, Cheng-Feng; Zhao, Qin-Shi

2014-06-01

332

L-Ascorbic acid metabolism during fruit development in an ascorbate-rich fruit crop chestnut rose (Rosa roxburghii Tratt).  

Science.gov (United States)

Chestnut rose (Rosa roxburghii Tratt) is a fruit crop that contains unusually high levels of l-ascorbic acid (AsA; ?1300 mg 100g(-1) FW). To explore the mechanisms underlying AsA metabolism, we investigated the distribution and abundance of AsA during fruit development. We also analyzed gene expression patterns, enzyme activities, and content of metabolites related to AsA biosynthesis and recycling. AsA first accumulated during late fruit development and continued to accumulate during ripening, with the highest accumulation rate near fruit maturity. The redox state of AsA in fruit was also enhanced during late fruit development, while leaf and other tissues had much lower levels of AsA and the redox state of AsA was lower. In mature fruit, AsA was mainly distributed in the cytoplasm of the mesocarp. Correlation analysis suggested that the gene expression patterns, enzyme activities, and related metabolite concentrations involved in the l-galactose pathway showed relatively high correlations with the accumulation rate of AsA. The gene expression pattern and activity of dehydroascorbate reductase (DHAR, EC 1.8.5.1) correlated strongly with AsA concentration, possibly indicating the crucial role of DHAR in the accumulation of high levels of AsA in chestnut rose fruit. Over expression of DHAR in Arabidopsis significantly increased the reduced AsA content and redox state. This was more effective than over expression of the l-galactose pathway gene GDP-d-mannose-3,5-epimerase (EC 5.1.3.18). These findings will enhance understanding of the molecular mechanisms regulating accumulation of AsA in chestnut rose. PMID:25019249

Huang, Ming; Xu, Qiang; Deng, Xiu-Xin

2014-09-01

333

Status of lipid peroxidation, glutathione, ascorbic acid, vitamin E and antioxidant enzymes in patients with osteoarthritis  

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Full Text Available Background : The exact pro-oxidant and antioxidant status in osteoarthritis patients is still not clear. To add a new insight to the question, changes in the erythrocyte lipid peroxidation products (MDA, levels of glutathione (GSH, ascorbic acid and plasma vitamin E (nonenzymatic antioxidant parameters; and activities of antioxidant enzymes superoxide dismutase (SOD, glutathione peroxidase (GPX, catalase in erythrocytes and plasma glutathione - S - transferase (GST were measured in patients with osteoarthritis. Aim: This work was undertaken to assess oxidative stress and antioxidant status in patients with osteoarthritis. Settings and design: The study was conducted in 20 patients and compared to controls. Levels of erythrocyte MDA, GSH, ascorbic acid, plasma vitamin E; and activities of antioxidant enzymes were measured in patients with osteoarthritis. materials and Methods: Erythrocyte GSH was measured by the method of Beutler et al. Ascorbic acid levels were measured by the method of Tietz. Plasma vitamin E levels were measured by the method of Baker et al. MDA was determined as the measure of thio barbituric acid reactive substances (TBARS. SOD activity in the hemolysate was measured by the method of Misra and Fridovich. Activity of catalase was measured by the method of Beers and Sizer. GPX activity was measured as described by Paglia and Valentine in erythrocytes, and Plasma GST activity was measured as described by Warholm et al. These parameters were measured in 20 patients and compared to controls. Statistical analysis: Statistical analysis between group 1 (controls and group 2 (patients was performed by the student?s t - test using the stat -view package. Results: It was observed that there was a significant increase in erythrocyte MDA levels; SOD, GPX and plasma GST activities; and a significant decrease in erythrocyte GSH, ascorbic acid, plasma vitamin E levels and catalase activity in patients with osteoarthritis when compared to controls. Conclusions: The results of our study suggest higher oxygen-free radical production, evidenced by increased MDA and decreased GSH, ascorbic acid, vitamin E and catalase activity, support to the oxidative stress in osteoarthritis. The increased activities of antioxidant enzymes may be a compensatory regulation in response to increased oxidative stress.

Surapaneni Krishna

2007-01-01

334

Effects of ascorbic acid and sugars on solubility, thermal, and mechanical properties of egg white protein gels.  

Science.gov (United States)

The effects of reducing sugars (fructose, glucose, ribose, and arabinose), sucrose, and ascorbic acid were studied on thermo-mechanical properties and crosslinking of egg white proteins (EWP) through Maillard reaction. Sugars (0%, 1%, 5%, and 10%) and ascorbic acid (0%, 0.25%, 0.5%, and 2.5%) were added to EWP solutions. Thermal denaturation and crosslinking of EWP were characterized by differential scanning calorimetry (DSC). Mechanical properties (failure strength, failure strain and Young's modulus) of modified and unmodified EWP gels were evaluated by texture analyzer. Ascorbic acid decreased thermal denaturation temperature of EWP, but the reducing sugars increased the denaturation temperature. DSC thermograms of EWP showed that ascorbic acid exhibited an exothermic transition (?110 °C) which was attributed to Maillard crosslinking of the protein. The reduction in pH (from 7.21 to ?6) and protein solubility of egg white protein gel (from ?70% to ?10%) provides further evidence of the formation of Maillard cross-linking. Reactive sugars (ribose and arabinose) increased the mechanical properties of EWP gels, whereas ascorbic acid decreased the mechanical properties. Generally, the effect of ascorbic acid was more pronounced than that of various reducing sugars on the thermal and mechanical properties of egg white proteins. PMID:24099933

Mohammadi Nafchi, Abdorreza; Tabatabaei, Ramin H; Pashania, Bita; Rajabi, Hadiseh Z; Karim, A A

2013-11-01

335

Influence of antioxidant (L- ascorbic acid on tolbutamide induced hypoglycaemia/antihyperglycaemia in normal and diabetic rats  

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Full Text Available Abstract Background Diabetes mellitus is a chronic metabolic disorder characterized by hyperglycaemia. Increased oxidative stress and decreased antioxidant levels are the leading cause of diabetes and diabetic complications. So it is felt that supplementation of antioxidants may be useful in controlling the glucose levels and to postpone the occurrence of diabetic complications. The objective of our study is to find the influence of antioxidant supplementation (L-ascorbic acid on tolbutamide activity in normal and diabetic rats. Methods L- ascorbic acid/tolbutamide/L-ascorbic acid + tolbutamide were administered orally to 3 different groups of albino rats of either sex in normal and diabetic condition. Blood samples were collected from retro-orbital puncture at different time intervals and were analyzed for blood glucose by GOD-POD method. Diabetes was induced by alloxan 100 mg/kg body weight administered by I.P route. Results L-ascorbic acid/ tolbutamide produced hypoglycaemic activity in a dose dependant manner in normal and diabetic condition. In the presence of L-ascorbic acid, tolbuatmide produced early onset of action and maintained for longer period compared to tolbutamide matching control. Conclusion Supplementation of antioxidants like L-ascorbic acid was found to improve tolbutamide response in normal and diabetic rats.

Vardhan Vishnu A

2005-03-01

336

Monitoring on the Presence of Ascorbic Acid in Not Prepacked Fresh Meat Preparations by a Validated HPLC Method  

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Full Text Available Ascorbic acid is a commonly-used food additive permitted in prepacked fresh meat preparations. Consequently, the addition of this antioxidant is subject to a specific packaging authorization. In this survey 180 samples of not prepacked fresh meat preparations have been analyzed in order to evaluate the diffusion of not authorized ascorbic acid additions. The ascorbic acid has been determined by a high performance liquid chromatography with diode array detection method, validated according to the European Legislation. Quantifiable concentrations of ascorbic acid (> LOQ = 20.1 mg · kg-1 were registered in 33 samples confirming a wide diffusion of not authorized additions. Moreover, low concentrations not attributable to a additives additions were detected in 14 samples. Ascorbic acid sources (tomato were declared on the label of these samples. Considering that the addition of this food additive is generally considered safe, these low concentrations registered may be useful for the determination of an allowable limit for the ascorbic acid in not prepacked fresh meat preparations.

Marco Iammarino

2012-04-01

337

Long-term culture of primary porcine mature hepatocytes in the medium supplemented with ascorbic acid 2-phosphate  

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Full Text Available In this study, the effect of ascorbic acid 2-phosphate (Asc2P was tested on porcine and rat mature hepatocytes in vitro. a. Asc2P increased the porcine, but not rat, albumin secretion and mRNA expression. The enhancing effect of Asc2P on porcine C/EBP alpha mRNA was observed in porcine mature hepatocytes. These data suggested that Asc2P played an important role in the regulation of porcine albumin mRNA level. b. The enhancing effect of Asc2P on ammonium metabolic activity was also observed in porcine, but not rat, mature hepatocytes. The porcine ornithine transcarbamylase (OTC and arginase mRNAs were augmented by Asc2P, indicating that Asc2P had a direct effect on the urea cycle. c. The porcine collagen type I and type III mRNA, but not type XII mRNA, were detected as well, sugessting that Asc2P did not have the effect on the non-parenchymal hepatocytes to induce collagen type I and III mRNA expression. d. Our RT-PCR analysis demonstrated that the porcine hepatocytes expressed the sodium-ascorbate co-transporters SVCT1 and SVCT2, however, the intensities of porcine sodium-ascorbate co-transporters SVCT1 and SVCT2 bands were not changed markedly. These findings indicated that the Asc2P had no effect on SVCT1 and SVCT2 mRNA expression. e. The enhancing effect of Asc2P on porcine albumin mRNA was inhibited by staurosporine, a portein kinase inhibitor. We conclude that the enhanced albumin mRNA by Asc2P might be due to activation of tyrosine protein kinase and/or PKC and the Asc2P enhanced porcine albumin mRNA mainly at the transcriptional step.

Noriko Sasaki

2010-11-01

338

Stability of copigmented anthocyanins and ascorbic acid in muscadine grape juice processed by high hydrostatic pressure.  

Science.gov (United States)

Intermolecular copigmentation is one of the mechanisms of stabilization of anthocyanins in nature and is also responsible for the characteristic color and stability of aged red wines. In the present study, the effect of polyphenol oxidase (PPO) activity on phytochemical stability of an ascorbic acid-fortified muscadine grape juice following high hydrostatic pressure (HHP) processing (400 and 550 MPa for 15 min) and after 21 d of storage at 25 degrees C was investigated. Addition of rosemary and thyme polyphenolic extracts (copigmentation) was evaluated as a means to stabilize anthocyanins and ascorbic acid during pressurization and subsequent storage. Polyphenolic extracts were partially purified in order to reduce their content of PPO substrates, and improve their stabilization properties within juice matrix. Overall PPO activity increased (3- and 2.5-fold) following HHP at 400 and 550 MPa, respectively, although it was significantly lower in copigmented treatments. Higher anthocyanin losses occurred at 400 (approximately 70%) than at 550 MPa (approximately 46%), which were correlated to antioxidant losses (r = 0.89). Similarly, greater ascorbic acid losses were observed at 400 (84%) than at 550 MPa (18%). Copigmentation increased anthocyanin retention in reference to pressurized controls (3- and 3.2-fold for rosemary and thyme treatments, respectively) and decreased ascorbic degradation (20 to 32%). In stored samples, higher anthocyanin content (>2-fold) and antioxidant capacity (>1.5-fold) was observed for copigmented treatments when compared to control juices. Addition of partially purified copigments increased muscadine grape juice color, antioxidant activity and also reduced phytochemical losses during HHP processing and storage. PMID:17995786

Del Pozo-Insfran, D; Del Follo-Martinez, A; Talcott, S T; Brenes, C H

2007-05-01

339

Effect of Salicylic Acid and Ascorbic Acid on Germination Indexes and Enzyme Activity of Sorghum Seeds under Drought Stress  

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Full Text Available Seed priming methods have been used to increase germination characteristics under stress conditions. The effects of drought stress (0, -4, -8, -12 and -16 bar and salicylic acid 25 ppm at 15 °C for 15 h and ascorbic acid 25 ppm at 15 °C for 15 h on germination percentage, germination index, means time to germination, normal seedling percentage and enzyme activity were assessed in the laboratory for sorghum seeds (Sorghum bicolor L.. Results showed that the highest germination percentage (83.33%, normal seedling percentage (69.67%, germination index (25.29 and the minimum means time to germination (2.87 were attained from priming with salicylic acid in control conditions. Therefore, seed priming significantly (p? 0.01 increased germination characteristics as compared to the unprimed under drought stress. Also, priming increased catalase and ascorbate peroxidase as compared to the unprimed seeds.

Tabatabaei S. A.

2013-11-01

340

Sensorially important aldehyde production from amino acids in model wine systems: impact of ascorbic acid, erythorbic acid, glutathione and sulphur dioxide.  

Science.gov (United States)

The efficiency of different white wine antioxidant systems in preventing aldehyde production from amino acids by oxidative processes is not well understood. The aim of this study was to assess the efficiency of sulphur dioxide alone and in combination with either glutathione, ascorbic acid or its stereoisomer erythorbic acid, in preventing formation of the sensorially important compounds methional and phenylacetaldehyde from methionine and phenylalanine in model white wine. UHPLC, GC-MS/MS, LC-MS/MS, flow injection analysis and luminescence sensors determined both compositional changes during storage, and sulphur dioxide-aldehyde apparent equilibrium constants. Depending on temperature (25 or 45°C) or extent of oxygen supply, sulphur dioxide was equally or more efficient in impeding the production of methional compared to the other antioxidant systems. For phenylacetaldehyde, erythorbic acid or glutathione with sulphur dioxide provided improved inhibition compared to sulphur dioxide alone, in conditions of limited oxygen consumption. The results also demonstrate the extent to which sulphur dioxide addition can lower the free aldehyde concentrations to below their aroma thresholds. PMID:23768362

Grant-Preece, Paris; Fang, Hongjuan; Schmidtke, Leigh M; Clark, Andrew C

2013-11-01

 
 
 
 
341

Enhancement of electrogenerated chemiluminescence of luminol by ascorbic acid at gold nanoparticle/graphene modified glassy carbon electrode.  

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Gold nanoparticle/graphene (GNP/GR) nanocomposite was one-pot synthesized from water soluble graphene and HAuCl? by hydrothermal method and characterized by TEM, Raman spectroscopy, XRD, XPS, UV-vis spectroscopy, and electrochemical impedance spectroscopy (EIS). Electrogenerated chemiluminescence (ECL) of luminol was investigated at the GNP/GR modified glassy carbon electrode (GNP/GR/GCE) and the GNP modified glassy carbon electrode (GNP/GCE) in aqueous solution respectively. The results revealed that one strong anodic ECL peak could be observed at ?0.8 V at two modified electrodes compared with that at the bare electrode. The intensity of the anodic ECL at the GNP/GR/GCE is weaker than that at the GNP/GCE, which should be due to the synergic effect of the enhancing effect of gold nanoparticles and the inhibiting effect of graphene on anodic luminol ECL. One strong cathodic ECL peak located at ?-0.8 V could be observed at the GNP/GR/GCE but not at the GNP/GCE, which should be result from the adsorbed oxygen at the graphene film. In the presence of ascorbic acid, the anodic ECL at the GNP/GR/GCE was enhanced more than 8-times, which is more apparent than that at the GNP/GCE. Whereas, the cathodic ECL peak was seriously inhibited at the GNP/GR/GCE. The enhanced ECL intensity at the GNP/GR/GCE varied linearly with the logarithm of ascorbic acid concentration in the range of 1.0 × 10(-8) to 1.0 × 10(-6)mol L(-1) with a detection limit of 1.0 × 10(-9) mol L(-1). The possible ECL mechanism was also discussed. PMID:25022493

Dong, Yongping; Gao, Tingting; Zhou, Ying; Chu, Xiangfeng; Wang, Chengming

2015-01-01

342

A novel nanocomposites sensor for epinephrine detection in the presence of uric acids and ascorbic acids  

Energy Technology Data Exchange (ETDEWEB)

Highlights: {center_dot} A novel PPy/AuNPs/SWCNTs nanomaterials biosensor was prepared to the selective determination of EP. {center_dot} The methods we employed to prepare PPy/AuNPs/SWCNTs nanomaterials are extremely simple. {center_dot} The PPy/AuNPs/SWCNTs nanocomposites biosensor we got from the results of experiments can totally eliminate the interference from AA and distinguish EP from UA. - Abstract: A novel nanocomposites film of conducting polymers including single-walled carbon nanotubes (SWCNTs), polypyrrole (PPy) and gold nanoparticles (AuNPs) modified electrode has been applied in voltammetric sensors to detect epinephrine (EP) sensitively when ascorbic acids (AA) and uric acids (UA) exist. The nanocomposites film of conducting polymers which show an excellent electrocatalystic activity for the oxidation of EP and UA was characterized by scanning electron microscopy (SEM) and electrochemical methods. The catalytic peak currents obtained from differential pulse voltammetry (DPV) increased linearly with increasing EP concentrations in the range of 4.0 x 10{sup -9}-1.0 x 10{sup -7} M with a detection limit of 2.0 x 10{sup -9} M (S/N = 3), respectively. The results showed that the nanocomposites of conducting polymers can selectively determine EP in the coexistence of a large amount of UA and AA. In addition, the sensor exhibited excellent sensitivity, selectivity and stability. The PPy/AuNPs/SWCNTs nanocomposites film can also be satisfactorily used for detecting EP in epinephrine hydrochloride injection when contain AA and UA, which also shows good recovery for determination of EP in some biological fluids.

Lu Xiaoquan, E-mail: luxq@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, LanZhou, 730070 (China); Li Yaya; Du Jie; Zhou Xibin; Xue Zhonghua; Liu Xiuhui; Wang Zhihua [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, LanZhou, 730070 (China)

2011-08-30

343

A novel nanocomposites sensor for epinephrine detection in the presence of uric acids and ascorbic acids  

International Nuclear Information System (INIS)

Highlights: · A novel PPy/AuNPs/SWCNTs nanomaterials biosensor was prepared to the selective determination of EP. · The methods we employed to prepare PPy/AuNPs/SWCNTs nanomaterials are extremely simple. · The PPy/AuNPs/SWCNTs nanocomposites biosensor we got from the results of experiments can totally eliminate the interference from AA and distinguish EP from UA. - Abstract: A novel nanocomposites film of conducting polymers including single-walled carbon nanotubes (SWCNTs), polypyrrole (PPy) and gold nanoparticles (AuNPs) modified electrode has been applied in voltammetric sensors to detect epinephrine (EP) sensitively when ascorbic acids (AA) and uric acids (UA) exist. The nanocomposites film of conducting polymers which show an excellent electrocatalystic activity for the oxidation of EP and UA was characterized by scanning electron microscopy (SEM) and electrochemical methods. The catalytic peak currents obtained from differential pulse voltammetry (DPV) increased linearly with increasing EP concentrations in the range of 4.0 x 10-9-1.0 x 10-7 M with a detection limit of 2.0 x 10-9 M (S/N = 3), respectively. The results showed that the nanocomposites of conducting polymers can selectively determine EP in the coexistence of a large amount of UA and AA. In addition, the sensor exhibited excellent sensitivity, selectivity and stability. The PPy/AuNPs/SWCNTs nanocomposites film can also be satisfactorily used for detecting EP in episfactorily used for detecting EP in epinephrine hydrochloride injection when contain AA and UA, which also shows good recovery for determination of EP in some biological fluids.

344

Sodium orthovanadate associated with pharmacological doses of ascorbate causes an increased generation of ROS in tumor cells that inhibits proliferation and triggers apoptosis  

International Nuclear Information System (INIS)

Graphical abstract: -- Abstract: Pharmacological doses of ascorbate were evaluated for its ability to potentiate the toxicity of sodium orthovanadate (Na3VO4) in tumor cells. Cytotoxicity, inhibition of cell proliferation, generation of ROS and DNA fragmentation were assessed in T24 cells. Na3VO4 was cytotoxic against T24 cells (EC50 = 5.8 ?M at 24 h), but in the presence of ascorbate (100 ?M) the EC50 fell to 3.3 ?M. Na3VO4 plus ascorbate caused a strong inhibition of cell proliferation (up to 20%) and increased the generation of ROS (4-fold). Na3VO4 did not directly cleave plasmid DNA, at this aspect no synergism was found occurring between Na3VO4 and ascorbate once the resulting action of the combination was no greater than that of both substances administered separately. Cells from Ehrlich ascites carcinoma-bearing mice were used to determine the activity of antioxidant enzymes, the extent of the oxidative damage and the type of cell death. Na3VO4 alone, or combined with ascorbate, increased catalase activity, but only Na3VO4 plus ascorbate increased superoxide dismutase activity (up to 4-fold). Oxidative damage on proteins and lipids was higher due to the treatment done with Na3VO4 plus ascorbate (2–3-fold). Ascorbate potentiated apoptosis in tumor cells from mice treated with Na3VO4. The results indicate that pharmacological doses of ascorbate enhance the generation of ROS induced by Na3VO4 in tumor cells causing inhibition of proliferation and apoptosis. Apoptosis induced by orthovanadate and ascorbate is closer related to inhibition on Bcl-xL and activation of Bax. Our data apparently rule out a mechanism of cell demise p53-dependent or related to Cdk2 impairment

345

Effect of temperature variations during cooking and storage on ascorbic acid contents of vegetables: a comparative study  

International Nuclear Information System (INIS)

Summary: Vegetables are generally boiled for cooking or stored in refrigerators. This results in loss of their nutritional values. Ascorbic acid is one of the important nutrients for human health. In this study, Ascorbic acid (vitamin-C) content of various vegetables of Pakistan was determined, and effect of boiling and freezing were compared with natural Ascorbic acid contents by HPLC. The maximum concentration of Ascorbic acid was found in green chilli: i.e. 105 mg /100 g in fresh state; while in boiled and frozen state its concentration is comparatively less: i.e. 85 and 92 mg/100 g respectively. The other vegetables like: cabbage, to mato, turnip, potato, spinach, onion, garlic, green pea, green beans and cauliflower contained greater amount of Ascorbic acid in their fresh state i.e. 30, 20, 25.3, 20, 30, 24.3, 31, 28.5, 30, 42 mg/100 g as compared to frozen (23.4, 13, 23.6, 15, 23.4, 14.1,25, 26.5, 27.0, and 39 mg/100g respectively) and boiled state (11.6, 9.3, 22.5, 10.0, 20.3, 13.1, 23, 25.2 and 35 mg /100g respectively). The minimum amount of Ascorbic acid was found in boiled state of carrot and lettuce: i.e. 4.0 mg/100 g. These results showed that freezing or boiling of vegetables causes significant lo ss of available Ascorbic acid contents, especially boiling. (author)

346

Evaluation of gamma irradiation effects on carotenoids, ascorbic acid and sugar contents of buriti fruit (Mauritia flexuosa L.)  

International Nuclear Information System (INIS)

Buriti (Mauritia flexuosa L.), a typical fruit from the Northeast and Center-West Amazon of Brazil, is used in many regional dishes. It is considered an excellent source of carotenoids that are A vitamin precursors, showing a majority of beta-carotene. It also presents ascorbic acid and sugar contents. Many studies have indicated that the lack of A vitamin is the main cause of night blindness and xerophthalmia. Also, ascorbic acid deficiency may cause scorbutic disease. The use of food irradiation is growing and represents an economic benefit to agriculture through the reduction of post-harvesting losses while maintaining food nutritional quality. In this study, buriti in natura was treated with gamma irradiation with doses of 0.5 kGy and 1.0 kGy. The objective was to evaluate the irradiation effects on total carotenoids, ascorbic acid and sugars concentrations of buriti. The fruit was evaluated through the total carotenoids analysis, by spectrophotometry, and the carotenoids (alpha and beta-carotene and lutein), ascorbic acid and sugars were determined by high performance liquid chromatography (HPLC). The results showed that buriti is an excellent source of total carotenoids (44600 ?g/100 g). The irradiation of buriti with the dose of 0.5 kGy did not significantly change carotenoids and sugars contents. However, there was a reduction of ascorbic acid concentration with an increase of the dose, which may have been caused by irradiation or by intrinsic and extrinsic factors that alter ascorbic acid stability in food, converting ascorbic to dehydroascorbic acid, while keeping the C vitamin active form. (author)

347

Suppressive effect of saturated acyl L-ascorbate on the oxidation of linoleic acid encapsulated with maltodextrin or gum arabic by spray-drying.  

Science.gov (United States)

6-O-Palmitoyl L-ascorbate was added to linoleic acid at various molar ratios of the ascorbate to the acid, the mixtures were emulsified with a maltodextrin or gum arabic solution, and the emulsions were spray-dried to produce microcapsules. At higher molar ratios, the oil droplets in the emulsions were smaller, and the oxidative stabilities of the encapsulated linoleic acid were higher for both the maltodextrin- and gum arabic-based microcapsules. 6-O-Capryloyl, caproyl, and lauroyl L-ascorbates, which were synthesized through lipase-catalyzed condensation in acetone, were also used for the microencapsulation of linoleic acid. Except for capryloyl L-ascorbate, the addition of a saturated acyl ascorbate, especially caproyl ascorbate, to linoleic acid was effective for preparing oil droplets of small particle diameter and for suppressing the oxidation of the encapsulated linoleic acid. PMID:12083870

Watanabe, Yoshiyuki; Fang, Xu; Minemoto, Yasumasa; Adachi, Shuji; Matsuno, Ryuichi

2002-07-01

348

Adaptive alterations in the fatty acids composition under induced oxidative stress in heavy metal-tolerant filamentous fungus Paecilomyces marquandii cultured in ascorbic acid presence.  

Science.gov (United States)

The ability of the heavy metal-tolerant fungus Paecilomyces marquandii to modulate whole cells fatty acid composition and saturation in response to IC50 of Cd, Pb, Zn, Ni, and Cu was studied. Cadmium and nickel caused the most significant growth reduction. In the mycelia cultured with all tested metals, with the exception of nickel, a rise in the fatty acid unsaturation was noted. The fungus exposure to Pb, Cu, and Ni led to significantly higher lipid peroxidation. P. marquandii incubated in the presence of the tested metals responded with an increase in the level of linoleic acid and escalation of electrolyte leakage. The highest efflux of electrolytes was caused by lead. In these conditions, the fungus was able to bind up to 100 mg g(-1) of lead, whereas the content of the other metals in the mycelium was significantly lower and reached from 3.18 mg g(-1) (Cu) to 15.21 mg g(-1) (Zn). Additionally, it was shown that ascorbic acid at the concentration of 1 mM protected fungal growth and prevented the changes in the fatty acid composition and saturation but did not alleviate lipid peroxidation or affect the increased permeability of membranes after lead exposure. Pro-oxidant properties of ascorbic acid in the copper-stressed cells manifested strong growth inhibition and enhanced metal accumulation as a result of membrane damage. Toxic metals action caused cellular modulations, which might contributed to P. marquandii tolerance to the studied metals. Moreover, these changes can enhance metal removal from contaminated environment. PMID:23132407

S?aba, Miros?awa; Gajewska, Ewa; Bernat, Przemys?aw; Fornalska, Magdalena; D?ugo?ski, Jerzy

2013-05-01

349

Modulation of Cholesterol and Copper Residue Levels in Muscles and Blood Serum of Finishing Broiler Chickens Fed Copper and Ascorbic Acid Supplements  

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Full Text Available To study the effect of Copper (Cu and ascorbic acid supplements on modulation of cholesterol and copper residue content of chicken muscles and blood serum, two hundred and forty finishing Anak broiler chickens of mixed sexes were randomly allotted to four dietary treatment groups with four replication of fifteen birds each. The feeding period was 5 weeks. The response to copper and ascorbic acid were such that dietary supplementation with 250 ppm Cu alone resulted in 30 and 19% reduction in pectoralis major and biceps femoris muscles cholesterol respectively. Supplementation with 250 ppm Cu + 100 ppm Ascorbic acid resulted in 29 and 12% reduction in muscles cholesterol while inclusion of 100 ppm ascorbic acid alone brought about 4 and 10% reduction in the two muscles respectively. Serum cholesterol reduced by 28% and the addition 100 ppm ascorbic acid reduced this to 26%. Ascorbic acid (100 ppm exerted 12% reduction in serum cholesterol. Ascorbic lowered the hypocholesterolemic potency of copper by about 1-7%. Combination of 100 ppm ascorbic and 250 ppm Cu slowed down rate of weight gain by 11% when compared with 250 ppm Cu alone as supplement, Supplementation with 100 ppm ascorbic alone improved carcass yield by 4% compared to 250 ppm Cu. Metalloprotein enzyme (AST and ALP activities were significantly increased with supplementation. Cu residue was more in biceps femoris than pectoralis major muscle. Above 30% reduction in Cu residue was noticed with addition of ascorbic acid.

A.O. Oso

2011-01-01

350

In-situ produced ascorbic acid as coreactant for an ultrasensitive solid-state tris(2,2'-bipyridyl) ruthenium(II) electrochemiluminescence aptasensor.  

Science.gov (United States)

Herein, an ultrasensitive solid-state tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy)(3)(2+)) electrochemiluminescence (ECL) aptasensor using in-situ produced ascorbic acid as coreactant was successfully constructed for detection of thrombin. Firstly, the composite of Ru(bpy)(3)(2+) and platinum nanoparticles (Ru-PtNPs) were immobilized onto Nafion coated glass carbon electrode, followed by successive adsorption of streptavidin-alkaine phosphatase conjugate (SA-ALP) and biotinylated anti-thrombin aptamer to successfully construct an ECL aptasensor for thrombin determination. In our design, Pt nanoparticles in Ru(bpy)(3)(2+)-Nafion film successfully inhibited the migration of Ru(bpy)(3)(2+) into the electrochemically hydrophobic region of Nafion and facilitated the electron transfer between Ru(bpy)(3)(2+) and electrode surface. Furthermore, ALP on the electrode surface could catalyze hydrolysis of ascorbic acid 2-phosphate to in-situ produce ascorbic acid, which co-reacted with Ru(bpy)(3)(2+) to obtain quite fast, stable and greatly amplified ECL signal. The experimental results indicated that the aptasensor exhibited good response for thrombin with excellent sensitivity, selectivity and stability. A linear range of 1 × 10(-15)-1 × 10(-8) M with an ultralow detection limit of 0.33 fM (S/N=3) was obtained. Thus, this procedure has great promise for detection of thrombin present at ultra-trace levels during early stage of diseases. PMID:21696941

Liao, Yuhong; Yuan, Ruo; Chai, Yaqin; Zhuo, Ying; Yuan, Yali; Bai, Lijuan; Mao, Li; Yuan, Shirong

2011-08-15

351

Ascorbic acid improves stability and pharmacokinetics of rifampicin in the presence of isoniazid.  

Science.gov (United States)

Bioavailability of rifampicin (RIF) from fixed dose combination (FDC) products remains problematic for effective control of tuberculosis (TB) owing to its degradation in the presence of isoniazid (INH) in the stomach acid environment. Ascorbic acid (ASC) is being added to the dissolution medium as well as the plasma sample as anti-oxidant to prevent degradation of RIF and also daily intake of ascorbic acid is recommended to control TB infection. However the role of ASC on the interaction between dissolution stability and in vivo bioavailability of RIF in the presence of INH has not been explored and therefore examined in the present study. RIF and its degradation product 3-FRSV were measured by dual wavelength spectroscopy. ASC significantly reduced RIF degradation or formation of 3-FRSV in the presence of INH (p<0.001) in the dissolution medium (pH 1.2) and showed increase in Cmax, AUC0-24, AUC0-? and t1/2 of RIF (p<0.001) as compared to that without ASC in rabbits. The study demonstrates that co-administration of ASC with RIF-INH combination can protect RIF from degradation in the acid environment and improve its bioavailability with effective control of TB. PMID:25151231

Rajaram, Subashini; Vemuri, Venkata Deepthi; Natham, Rajendran

2014-11-01

352

Microencapsulation-protected l-ascorbic acid for the application of human epithelial HaCaT cell proliferation.  

Science.gov (United States)

Abstract l-ascorbic acid is an abundant water-soluble nutrient found in vegetables and fruits. It enhances the cell proliferation, which is helpful in wound healing process. However, it is relatively unstable and easily degraded under external environments including acidity, alkalinity, evaporation, heat, oxidization, light or moisture. Its storage remains challenged. This study reported the development of l-ascorbic acid microcapsules using the natural protein, gelatin, and the natural polysaccharide, agar, as the wall protection carrier. The physical properties including entrapment efficiency, particle size, surface morphology, chemical compositions and release profile were identified. The cell proliferation of l-ascorbic acid microcapsules was stronger than the free drug. Significant cell growth in microencapsulated l-ascorbic acid-treated human epithelial HaCaT cells was observed when compared with untreated control. Since cell proliferation and wound repair are closely related, it is believed that l-ascorbic acid microcapsules would effectively increase the potential effect of wound healing activity in human skin. PMID:24963963

Lam, P-L; Kok, S H-L; Bian, Z-X; Lam, K-H; Gambari, R; Lee, K K-H; Chui, C-H

2014-01-01

353

Biological Significance of Ascorbic Acid (Vitamin C in Human Health - A Review  

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Full Text Available The recognition of vitamin C (Ascorbic acid is associated with history of an unrelenting search for the cause of the ancient hemorrhagic disease scurvy. Isolated in 1928, vitamin C is essential for the development and maintenance of connective tissues. It plays an important role in bone formation, wound healing and the maintenance of healthy gums. Vitamin C plays an important role in a number of metabolic functions including the activation of the B vitamin, folic acid, the conversion of cholesterol to bile acids and the conversion of the amino acid, tryptophan, to the neurotransmitter, serotonin. It is an antioxidant that protects body from free radicals` damages. It is used as therapeutic agent in many diseases and disorders. Vitamin C protects the immune system, reduces the severity of allergic reactions and helps fight off infections.

Khalid Iqbal

2004-01-01

354

Protective Effect of Ascorbic Acid on Molecular Behavior Changes of Hemoglobin Induced by Magnetic Field  

Science.gov (United States)

With the use of electricity and industrialization of societies, humans are commonly exposed to static magnetic field induced by electric currents. The putative mechanisms by which Static Magnetic Field (SMF) may affect biological systems is that of increasing free radical life span in organisms. To test this hypothesis, we investigate the effect of ascorbic acid (Vitamin C) treatment on the changes in the molecular behavior of hemoglobin as a result of exposure of the animals to magnetic field in the occupation levels. By measuring the relative permittivity, dielectric loss, relaxation time, conductivity, radius and diffusion coefficient of aqueous solutions of hemoglobin. These measurements were calculated in the frequency range of (100 Hz-100 kHz) to give more information about molecular behavior. Twenty four male albino rats were equally divided into four groups 1, 2, 3 and 4. Animals of group 1, were used as control, animals of group 2, were exposed to (0.2T) magnetic field and that of group 3, 4, were treated with Ascorbic Acid by two doses group 3 (20 mg kg-1 body weight), group 4 (50 mg kg-1 body weight) orally half hour before exposure to magnetic field. The sub chronic exposure expanded (1 h day-1) for 30 consecutive days. The results indicated that exposure of animals to magnetic field resulted in changes in the molecular behavior of hemoglobin molecule while treatment with ascorbic acid afforded comparatively more significant amelioration in these molecular changes, via decreasing the radical pair interaction of magnetic field with biological molecules.

Hassan, Nahed S.; Abou Aiad, T. H. M.

355

Influence of heating conditions and ascorbic acid concentration over furan formation in starchy model systems  

DEFF Research Database (Denmark)

Furan, a potential carcinogen, can be formed in foods processed at high temperatures such as coffee, baby foods, bread and snacks. Although there is still no clarity about the risks associated with the current intake levels of dietary furan, to limit the furan occurrence in foods may be considered as a challenge in the prevention of human diseases as cancer. Considering that heat processed starchy products are characterized by their high worldwide consumption, we decided to dig into the mechanisms that would define their final content of furan. The present study explored the effect of heating conditions (frying and baking) and ascorbic acid concentration over furan occurrence in a starchy model system. Two different formulations of wheat flour dough (WF: wheat flour and WF-AA: wheat flour and ascorbic acid) were prepared with a 40 % of moisture (wb). Then, dough were cut in circle chips (40 mm of diameter ; 2.3 mm of thickness) which were fried and baked at 170°C and 200°C for 5, 7 and 9 minutes. Furan contents of heat processed products were quantified by GC-MS. WF fried products contained higher furan levels than baked ones for all different processing times (e.g. 97 % higher furan in 5 minutes fried chips). For the case of WF-AA chips baking produced more furan compared to the frying (e.g. 58 % higher furan in 7 minutes baked chips). For all process conditions ascorbic acid addition produced an increase in furan levels (?17%-58% in frying and ?74-98 % in baking). As for Maillard reactions in general, for all samples, an increase in furan level was observed when the moisture content decreased. Additionally, in fried products furan level was directly proportional to their oil uptake. We conclude that for the present model conditions, ascorbic acid improves the furan generation, having a stronger effect in baked products. We also propose that while lipid oxidation has been considered as one of main furan generation routes, for this particular case, it should not have a greater influence over furan formation; since frying experiments were realized with commercial sunflower oil with added antioxidant. Finally, considering that furan is an unpolar compound, for fried product the oil uptake may be responsible for the higher furan retention.

Mariotti, Salomé; Granby, Kit

356

Electroanalysis of ascorbic acid: A comparative study of laser ablation voltammetry and sonovoltammetry  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The electroanalytical detection of L-ascorbic acid via its two electron oxidation in aqueous solution is the subject of a comparison of two voltammetric methodologies both of which rely in part on electrode abrasion. First in sonovoltammetry cavitational collapse at the electrode-solution interface can lead to electrode erosion and activation. Second in laser ablation voltammetry (LAV) a 10 Hz pulsed laser (532 nm, 0.7 mJ per pulse) is used to abrade the electrode. In both cases the concomita...

Akkermans, Rp; Wu, M.; Bain, Cd; Fidel-suarez, M.; Compton, Rg

1998-01-01

357

Genetic evidence for the role of GDP-mannose in plant ascorbic acid (vitamin C) biosynthesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Vitamin C (l-ascorbic acid; AsA) acts as a potent antioxidant and cellular reductant in plants and animals. AsA has long been known to have many critical physiological roles in plants, yet its biosynthesis is only currently being defined. A pathway for AsA biosynthesis that features GDP-mannose and l-galactose has recently been proposed for plants. We have isolated a collection of AsA-deficient mutants of Arabidopsis thaliana that are valuable tools for testing of an AsA biosynthetic pathway....

Conklin, Patricia L.; Norris, Susan R.; Wheeler, Glen L.; Williams, Elizabeth H.; Smirnoff, Nicholas; Last, Robert L.

1999-01-01

358

Gold nanoparticles confined in vertically aligned silica nanochannels and their electrocatalytic activity toward ascorbic acid.  

Science.gov (United States)

A facile method of confining gold nanoparticles (AuNPs) in silica nanochannels aligned perpendicularly to an underlying electrode surface is reported. The nanochannel surface carrying a layer of (3-aminopropyl)triethoxy silane (APTS) displays a strong electrostatic interaction with AuCl4(-), eventually resulting in the confinement of AuNPs inside the nanochannels after chemical reduction. As-prepared AuNPs in APTS-modified mesoporous silica film (APTS-MSF) are highly dispersed with a narrow size distribution. Furthermore, these AuNPs are free of protecting ligands and exhibit a good electrochemical catalytic activity toward the oxidation of ascorbic acid. PMID:25146883

Ding, Longhua; Li, Wanzhen; Sun, Qinqin; He, Yayun; Su, Bin

2014-09-26

359

Ascorbic Acid and the Brain: Rationale for the Use against Cognitive Decline  

Science.gov (United States)

This review is focused upon the role of ascorbic acid (AA, vitamin C) in the promotion of healthy brain aging. Particular attention is attributed to the biochemistry and neuronal metabolism interface, transport across tissues, animal models that are useful for this area of research, and the human studies that implicate AA in the continuum between normal cognitive aging and age-related cognitive decline up to Alzheimer’s disease. Vascular risk factors and comorbidity relationships with cognitive decline and AA are discussed to facilitate strategies for advancing AA research in the area of brain health and neurodegeneration. PMID:24763117

Harrison, Fiona E.; Bowman, Gene L.; Polidori, Maria Cristina

2014-01-01

360

Role of ascorbic acid and ? tocopherol in alleviating salinity stress on flax plant (Linum usitatissimum L.)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Salinity is one of the environmental challenges in the world affecting on several physiological processes and the most limiting factor of plant productivity and quality. Two pot experiments were conducted at the wire house of National Research Centre, Cairo, Egypt during two successive seasons of 2010/2011 and 2011/2012 to assess the efficiency of two antioxidant vitamins (ascorbic acid at 1.13 and 2.27 mM or ? tocopherol at 0.46 and 0.93 mM) and/or salinity stress at (0.0, 3.08, 6.16, 9.23 ...

Mervat Sh. Sadak; Dawood, Mona G.

2014-01-01

 
 
 
 
361

Ascorbic acid suppresses endotoxemia and NF-?B signaling cascade in alcoholic liver fibrosis in guinea pigs: A mechanistic approach  

International Nuclear Information System (INIS)

Alcohol consumption increases the small intestinal bacterial overgrowth (SIBO) and intestinal permeability of endotoxin. The endotoxin mediated inflammatory signaling plays a major role in alcoholic liver fibrosis. We evaluated the effect of ascorbic acid (AA), silymarin and alcohol abstention on the alcohol induced endotoxemia and NF-?B activation cascade pathway in guinea pigs (Cavia porcellus). Guinea pigs were administered ethanol at a daily dose of 4 g/kg b.wt for 90 days. After 90 days, ethanol administration was stopped. The ethanol treated animals were divided into abstention, silymarin (250 mg/kg b.wt) and AA (250 mg/kg b.wt) supplemented groups and maintained for 30 days. The SIBO, intestinal permeability and endotoxin were significantly increased in the ethanol group. The mRNA expressions of intestinal proteins claudin, occludin and zona occludens-1 were significantly decreased in ethanol group. The mRNA levels of inflammatory receptors, activity of IKK? and the protein expressions of phospho-I?B?, NF-?B, TNF-?, TGF-?1 and IL-6 were also altered in ethanol group. The expressions of fibrosis markers ?-SMA, ?1 (I) collagen and sirius red staining in the liver revealed the induction of fibrosis. But the supplementation of AA could induce greater reduction of ethanol induced SIBO, intestinal barrier defects, NF-?B activation and liver fibrosis than silymarin. The possible mechanism may be the inhibitory effect of AA on SIBO, intestinal barrier defect and IKK?, which decreased the activation of NF-?B and synthesis of cytokines. This might have led to suppression of HSCs activation and liver fibrosis. - Highlights: • Alcohol increases intestinal bacterial overgrowth and permeability of endotoxin. • Endotoxin mediated inflammation plays a major role in alcoholic liver fibrosis. • Ascorbic acid reduces endotoxemia, NF-?B activation and proinflammatory cytokines. • AA's action is by inhibition of SIBO, IKK? and alteration of intestinal permeability. • This might have led to suppression of HSCs activation and liver fibrosis

362

The Protective Effects of Ethanolic Extract of Garlic and Ascorbic Acid on Cadmium-Induced Oxidative Stress  

Directory of Open Access Journals (Sweden)

Full Text Available The protective effects of ethanolic extract of garlic (Allium sativum and ascorbic acid on cadmium-induced oxidative stress were investigated in the liver and kidney of male rats by monitoring the lipid peroxides profiles, enzymatic and non-enzymatic antioxidants activities. The rats were pretreated with ethanolic extract of garlic (100 mg kg-1 body weight or ascorbic acid (100 mg kg-1 body weight orally for 4 weeks. These rats were also given cadmium (4 g kg-1 body weight intraperitoneally for 3 days at the last week of treatment. Another group of rats were either given extract (100 mg kg-1 body weight daily, orally for 4 weeks or ascorbic acid (100 mg kg-1 body weight daily, orally for 4 weeks or cadmium (4 g kg-1 body weight for 3 days or distilled water. The results showed a significant increase in the activities of catalase and Super Oxide Dismutase (SOD in the liver and kidney of ethanolic extract of garlic and ascorbic acid pretreated rats compared to control (p< 0.05. Lipid peroxides levels were significantly reduced in the liver and kidney of pretreated rats compared to control (p< 0.05. Reduced glutathione (GSH levels were significantly increased in both organs of ascorbic acid and ethanolic extract of garlic pretreated rats when compared to control (p< 0.05. The study revealed the potential of ethanolic extract of garlic to prevent oxidative damage induced by acute dose of cadmium.

I.V. Ogungbe

2008-01-01

363

Immunomodulatory role of Ocimum gratissimum and ascorbic acid against nicotine-induced murine peritoneal macrophages in vitro.  

Science.gov (United States)

The aim of this present study was to evaluate the immune functions and immune responses in nicotine-induced (10 mM) macrophages and concurrently establish the immunomodulatory role of aqueous extract of Ocimum gratissimum (Ae-Og) and ascorbic acid. In this study, nitrite generations and some phenotype functions by macrophages were studied. Beside that, release of Th1 cytokines (TNF-?, IL-12) and Th2 cytokines (IL-10, TGF-?) was measured by ELISA, and the expression of these cytokines at mRNA level was analyzed by real-time PCR. Ae-Og, at a dose of 10 ?g/mL, significantly reduced the nicotine-induced NO generation and iNOSII expression. Similar kinds of response were observed with supplementation of ascorbic acid (0.01 mM). The administration of Ae-Og and ascorbic acid increased the decreased adherence, chemotaxis, phagocytosis, and intracellular killing of bacteria in nicotine-treated macrophages. Ae-Og and ascorbic acid were found to protect the murine peritoneal macrophages through downregulation of Th1 cytokines in nicotine-treated macrophages with concurrent activation of Th2 responses. These findings strongly enhanced our understanding of the molecular mechanism leading to nicotine-induced suppression of immune functions and provide additional rationale for application of anti-inflammatory therapeutic approaches by O. gratissimum and ascorbic acid for different inflammatory disease prevention and treatment during nicotine toxicity. PMID:22220218

Mahapatra, Santanu Kar; Chakraborty, Subhankari Prasad; Roy, Somenath

2011-01-01

364