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Sample records for ascorbic acid inhibits

  1. 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

  2. Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  3. Studies on rancidity inhibition in frozen horse mackerel (Trachurus trachurus) by citric and ascorbic acids

    OpenAIRE

    Aubourg, Santiago P.; Pe?rez-alonso, Francisco; Gallardo, Jose? Manuel

    2004-01-01

    This study is aimed to investigate the effect of aqueous solutions of citric acid (CA) and ascorbic acid (AA) on the lipid stability of horse mackerel (Trachurus trachurus) fillets and whole fish during frozen storage (up to 6 and 9 months, respectively) by means of a soaking pretreatment. Best oxidation inhibition results on fish fillets were obtained when employing a 0.5% CA solution. Lower (p

  4. Inhibition of ascorbate peroxidase by salicylic acid and 2,6-dichloroisonicotinic acid, two inducers of plant defense responses.

    OpenAIRE

    Durner, J.; Klessig, D. F.

    1995-01-01

    In recent years, it has become apparent that salicylic acid (SA) plays an important role in plant defense responses to pathogen attack. Previous studies have suggested that one of SA's mechanisms of action is the inhibition of catalase, resulting in elevated levels of H2O2, which activate defense-related genes. Here we demonstrate that SA also inhibits ascorbate peroxoidase (APX), the other key enzyme for scavenging H2O2. The synthetic inducer of defense responses, 2,6-dichloroisonicotinic ac...

  5. 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

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

    Directory of Open Access Journals (Sweden)

    Kulkarni S

    2008-01-01

    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.

  7. 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

  8. Ascorbic acid and reactive oxygen species are involved in the inhibition of seed germination by abscisic acid in rice seeds

    OpenAIRE

    Ye, Nenghui; Zhu, Guohui; Liu, Yinggao; Zhang, Aying; Li, Yingxuan; Liu, Rui; Shi, Lu; Jia, Liguo; Zhang, Jianhua

    2011-01-01

    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. The possible links among ABA, reactive oxygen species (ROS), ascorbic acid (ASC), and GA during rice seed germination were investigated. Unlike in non-seed tissues where ROS production is increased by ABA, ABA reduced ROS production in imbibed rice seeds, especially in the embryo region. Such reduced ROS also led to...

  9. Ascorbic acid transport in brain microvascular pericytes.

    Science.gov (United States)

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

    2015-03-01

    Intracellular vitamin C, or ascorbic acid, has been shown to prevent the apoptosis of cultured vascular pericytes under simulated diabetic conditions. We sought to determine the mechanism by which ascorbate is transported into pericytes prior to exerting this protective effect. Measuring intracellular ascorbate, we found that pericytes display a linear uptake over 30 min and an apparent transport Km of 21 ?M, both of which are consistent with activity of the Sodium-dependent Vitamin C Transporter 2 (SVCT2). Uptake of both radiolabeled and unlabeled ascorbate was prevented by inhibiting SVCT2 activity, but not by inhibiting the activity of GLUT-type glucose transporters, which import dehydroascorbate to also generate intracellular ascorbate. Likewise, uptake of dehydroascorbate was prevented with the inhibition of GLUTs, but not by inhibiting the SVCT2, indicating substrate specificity of both transporters. Finally, presence of the SVCT2 in pericytes was confirmed by western blot analysis, and immunocytochemistry was used to localize it to the plasma membrane and intracellular sites. Together, these data clarify previous inconsistencies in the literature, implicate SVCT2 as the pericyte ascorbate transporter, and show that pericytes are capable of concentrating intracellular ascorbate against a gradient in an energy- and sodium-dependent fashion. PMID:25645015

  10. Ascorbic Acid Inhibits Development of Tolerance and Dependence to Opiates in Mice: Possible Glutamatergic or Dopaminergic Modulation

    OpenAIRE

    Kulkarni S.; Deshpande C; Dhir A

    2008-01-01

    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...

  11. delta-Aminolevulinate dehydratase inhibition by ascorbic acid is mediated by an oxidation system existing in the hepatic supernatant.

    Science.gov (United States)

    Beber, F A; Wollmeister, J; Brigo, M J; Silva, M C; Pereira, C N; Rocha, J B

    1998-01-01

    The effect of ascorbic acid (AA) on hepatic delta-aminolevulinic acid dehydratase (ALA-D) activity was studied. AA decreased enzyme activity by reducing maximum velocity and tended to increase the Michaelis constant. ALA-D inactivation by AA occurred similarly both in air and argonium atmosphere incubation. DTT reduced considerably the inhibitory effect of AA on ALA-D, but glutathione was ineffective in reversing inactivation. These data indicate that inhibition occurs mainly due to an acceleration of the oxidation rate mediated by the hepatic supernatant utilizing AA in sulfhydryl groups of cysteine residues present at the ALA-D active site. AA probably acts on cysteine from the ALA-D B site since cucumber and radish leaves ALA-D was not inhibited by AA (up to 16 mM). The addition of free radical scavengers to the medium did not alter ALA-D inactivation caused by AA, indicating that active oxygen species formed during AA oxidation were not directly related to -SH oxidation. The chelation of zinc ions from the enzyme by EDTA turned ALA-D more susceptible to the inhibitory effect of AA. This effect seems to involve mainly ZnB, which is known to bind to four cysteines. The present data suggest that AA may participate in the regulation of the heme biosynthesis pathway by promoting a reversible inactivation of ALA-D. PMID:9637949

  12. Effects of ascorbic acid and sodium ascorbate on cyclic nucleotide metabolism in human lymphocytes.

    Science.gov (United States)

    Atkinson, J P; Weiss, A; Ito, M; Kelly, J; Parker, C W

    1979-01-01

    L-ascorbic acid (LAA) augmented cGMP many-fold in highly purified human peripheral blood lymphocytes. The cGMP response occurred within 10 sec and persisted for at least 60 min. D-ascorbic acid (DAA) and dehydroascorbic acid (DHAA) were also equally active in enhancing cGMP concentrations but metabolic precursors of ascorbic acid and other inorganic acids did not increase cGMP levels. Determination of the amount of DHAA contaminating the LAA precluded the possibility that it was solely responsible for the enhanced cGMP levels. The sodium or calcium salts of ascorbic acid did not increase cGMP concentrations. If these neutralized preparations were acidified, increased cGMP concentrations were then noted. In broken cell preparations, LAA, DAA, and DHAA and to a lesser extent sodium ascorbate (NaA) enhanced guanylate cyclase activity while neither inhibited cAMP or cGMP phosphodiesterase (PDE) activity. The possible role of H2O2, fatty acid liberation, prostaglandin production, oxidizing-reducing agents, and free radical formation in mediating the effects of ascorbic acid on cGMP levels were evaluated, but none of these potential mechanisms were definitively proven to be a required intermediary for the cGMP enhancing activity of ascorbic acid. LAA, DHAA or NaA did not induce lymphocyte transformation or modulate lectin-induced mitogenesis. PMID:36416

  13. Ascorbic acid specific utilization by some yeasts.

    Science.gov (United States)

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

    1986-09-01

    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

  14. 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.

  15. Ascorbic acid: effects on ricin intoxicated HeLa cells

    International Nuclear Information System (INIS)

    A study of ricin was made to acertain if ascorbic acid had a specific effect on diphteria toxin or could it prevent the action of toxins from various sources with an activity different than that of diphteria. Ricin was isolated by suspending the defatted meal in double distilled water and adjusting to pH 3.8. The suspension was filtered, the precipitate collected and again dissolved in double distilled water. After saturation with ammonium sulfate, precipitate was collected by centrifugation. The concentration of ricin needed to inhibit at least 50% of the incorporation of (14C) alanine into trichloroacetic acid (TCA) precipitable material was determined. HeLa cells are protected by using ascorbic acid. Ascorbic acid or citric acid was added to the medium 30 min prior to the addition of toxic protein. The isolated ricin prevented the incorporation of (14C) alanine into TCA precipitate material in HeLa cells at levels of 11.5 to 0.00115 microgram of the toxin per ml of culture media. The addition of 100 microgram of ascorbic acid to the HeLa cell cultures 30 min prior to the addition of ricin completely prevented the inhibition of protein synthesis by ricin. Lesser amounts of ascorbic acid offered less protection. Although these data do not elucidate the mechanism of action of ascorbic acid, they show that in vitro ascorbic acid can prevent the action of this poisonous toxin. The data support the use of pharmacological doses of ascorbic acid in tharmacological doses of ascorbic acid in the treatment of various cases of poisoning. (Iwakiri, K.)

  16. 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)

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

    2001-01-01

    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.

  17. Regulation of collagen synthesis by ascorbic acid: characterization of the role of ascorbate-stimulated lipid peroxidation.

    Science.gov (United States)

    Geesin, J C; Hendricks, L J; Falkenstein, P A; Gordon, J S; Berg, R A

    1991-10-01

    Recently, we have described the ability of traditional lipid peroxidation inhibitors to inhibit ascorbate-stimulated collagen synthesis. In order to characterize further this effect, we have tested the ability of known and potential inhibitors of lipid peroxidation for their effects on ascorbate-stimulated collagen synthesis and lipid peroxidation. In our experiments, mannitol, a water soluble antioxidant, had no effect on ascorbate-induced collagen synthesis nor on lipid peroxidation. However, alpha-tocopherol, which is a lipophilic antioxidant, inhibited both effects of ascorbate. Superoxide dismutase, catalase, and their polyethylene glycol conjugate forms did not inhibit the ascorbate-stimulated collagen synthesis or lipid peroxidation. In addition, no effect was seen with the oxygen radical scavengers isopropanol, ethanol, or dimethyl sulfoxide. Two iron chelators, o-phenanthroline and alpha,alpha-dipyridyl, both inhibited ascorbate-induced lipid peroxidation and collagen synthesis, consistent with the previously described iron-dependence of lipid peroxidation by ascorbate. These results support a correlation between collagen synthesis and lipid peroxidation and provide a theory for the mechanism of ascorbic acid regulation of collagen synthesis. PMID:1898082

  18. 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

  19. INFLUENCE OF ASCORBIC ACID ON EGG QUALITY

    OpenAIRE

    Souza, Pedro Alves; Souza, Hirasilva Borba Alves; Oba, Alexandre; Gardini, Claudio Henrique Cruz

    2001-01-01

    The egg quality may be influenced by some nutrients added to laying hens diets and among these nutrients, the ascorbic acid is included. According to some researches, this acid, besides of improving the quality, it can increase the egg production and weight. In addition, it reduces the quantity of cracked eggs and food intake. In order to contribute with more information, this experiment was developed. Concentrations of 100; 150 and 200mg/kg of ascorbic acid were added to rations of laying he...

  20. The kinetics of oxidation of bilirubin and ascorbic acid in solution

    Science.gov (United States)

    Solomonov, A. V.; Rumyantsev, E. V.; Kochergin, B. A.; Antina, E. V.

    2012-07-01

    The results of a comparative study of the oxidation of bilirubin, ascorbic acid, and their mixture in aqueous solutions under the action of air oxygen and hydrogen peroxide are presented. The observed and true rate constants for the oxidation reactions were determined. It was shown that the oxidation of tetrapyrrole pigment occurred under these conditions bypassing the stage of biliverdin formation to monopyrrole products. Simultaneous oxidation of bilirubin and ascorbic acid was shown to be accompanied by the inhibition of ascorbic acid oxidation by bilirubin, whereas ascorbic acid itself activated the oxidation of bilirubin.

  1. Enterococcus faecalis Grows on Ascorbic Acid

    OpenAIRE

    Mehmeti, Ibrahim; Solheim, Margrete; Nes, Ingolf F.; Holo, Helge

    2013-01-01

    We show that Enterococcus faecalis can utilize ascorbate for fermentative growth. In chemically defined media, growth yield was limited by the supply of amino acids, and the cells showed a much higher demand for amino acids than when they were grown on glucose.

  2. Electron-impact fragmentation of ascorbic acid

    Science.gov (United States)

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

    2009-04-01

    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.

  3. Exploration of effects of emodin in selected cancer cell lines: enhanced growth inhibition by ascorbic acid and regulation of LRP1 and AR under hypoxia-like conditions.

    Science.gov (United States)

    Masaldan, Shashank; Iyer, Vidhya V

    2014-01-01

    This study explores the link between the antiproliferative activity of emodin through the generation of reactive oxygen species (ROS) in various cancer cell lines and the expression of the androgen receptor (AR) in the prostate cancer cell lines LNCaP (androgen-sensitive) and PC-3 (androgen-refractory), as well as the pro-metastatic low-density lipoprotein receptor-related protein 1 (LRP1) in the above prostate cancer cells and the nonprostate cell lines A549 (lung), HCT-15 (colon) and MG-63 (bone) under normoxic and hypoxia-like conditions. Among all cell lines, emodin showed most growth inhibition in LNCaP, followed by A549. The mechanism of cytotoxicity of emodin was postulated to be the widely reported ROS generation, based on the observations of poor in vitro radical-scavenging activity and increased growth inhibition of emodin by ascorbic acid (AA) pre-treatment owing to the additive effects of ROS generation by emodin and pro-oxidant effects of AA. Emodin downregulated AR in LNCaP under normoxic and hypoxia-like conditions (simulated by CoCl(2)) and LRP1 under normoxia. Emodin upregulated LRP1 in other cell lines, except HCT-15, under normoxic, and even more markedly under hypoxia-like conditions. The downregulation of AR in LNCaP and upregulation of LRP1 in all cell lines, except HCT-15, under hypoxia-like conditions along with growth inhibition by emodin, suggests that emodin may be a useful therapeutic option against androgen-sensitive prostate cancer and other such LRP1-expressing cancers to attempt the targeting of the elevated LRP1 levels to allow the uptake of emodin and/or any other accompanying therapeutic agents by LRP1. PMID:23212659

  4. Inhibition of oxidative degradation of hyaluronic acid by uric acid.

    Science.gov (United States)

    Liu, K M; Swann, D; Lee, P; Lam, K W

    1984-08-01

    It has been postulated that glycosaminoglycans in the trabeculum have an influence on aqueous humor drainage. Ascorbate reduces the viscosity of hyaluronic acid, and also increases outflow facility. Our recent observation of high urate concentrations in some glaucomatous eyes led us to study the influence of urate on oxidative degradation of hyaluronic acid by ascorbate. The viscosity of rooster comb hyaluronic acid was reduced slowly by ascorbate. Cupric sulfate accelerated ascorbate oxidation and also enhanced hyaluronic acid degradation. Urate inhibited ascorbate oxidation and prevented the copper catalyzed oxidative degradation of rooster comb hyaluronic acid. The range of urate concentrations used in this study was within the range of urate concentrations observed in glaucomatous eyes. The partially purified umbilical cord hyaluronic acid had lower viscosity than rooster comb hyaluronic acid, and rapidly degraded in the presence of ascorbate. The ascorbate effect on umbilical cord hyaluronic acid was partially prevented by urate. PMID:6488856

  5. An investigation of rancidity inhibition during frozen storage of Wels catfish (Silurus glanis) fillets by previous ascorbic and citric acid treatment

    OpenAIRE

    Pourashouri, Parastoo; Shabanpour, Bahareh; Aubourg, Santiago P.; Rohi, Javad Daghigh; Shabani, Ali

    2009-01-01

    The effect of preliminary ascorbic and citric acid (AA and CA, respectively) soaking treatments on the rancidity development in Wels catfish (Silurus glanis) fillets during further frozen storage (?18 °C; up to 6 months) was studied. Rancidity development was measured by biochemical quality indices (formation of free fatty acids, peroxides and secondary oxidation products) and compared with sensory analysis (appearance, rancid odour and consistency) and general chemical analyses (pH, expre...

  6. Spectrophotometric determination of copper with ascorbic acid

    International Nuclear Information System (INIS)

    Copper has been determined spectrophotometrically by using ascorbic acid as a chromagenic reagent. The complex formed in basic medium is measured for its absorbance at 340 n.m. Interference for 23 cations and 9 anions has also been checked. Effect of pH, time, temperature, ammonia, reagent concentration and interferents has been report. (author)

  7. Transfer of ascorbic acid across the vascular endothelium: mechanism and self-regulation

    OpenAIRE

    May, James M.; Qu, Zhi-chao; Qiao, Huan

    2009-01-01

    To determine how ascorbic acid moves from the bloodstream into tissues, we assessed transfer of the vitamin across the barrier generated by EA.hy926 endothelial cells when these were cultured on semipermeable filter supports. Ascorbate transfer from the luminal to the abluminal compartment was time dependent, inhibited by anion channel blockers and by activation of protein kinase A, but was increased by thrombin. Ascorbate transfer occurred by a paracellular route, since it did not correlate ...

  8. Natural electrophoresis of norepinephrine and ascorbic acid.

    OpenAIRE

    Dillon, P. F.; Root-bernstein, R. S.; Sears, P. R.; Olson, L. K.

    2000-01-01

    The electric field produced by cell membranes, extending only a few nanometers, is 1000 times stronger than the electric fields required to produce dissociation of molecular complexes. Using the complex formed by norepinephrine (NE) and ascorbic acid (AA), we have demonstrated the quantitative binding of AA to NE, the use of capillary electrophoresis to measure quantitative binding of nonelectrolyte complexes, the determination of a dissociation constant (Kd) from electric field-dissociation ...

  9. Allosteric modulation of retinal GABA receptors by ascorbic acid

    OpenAIRE

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

    2011-01-01

    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...

  10. Hepatoprotective Effect of Vitamin C (Ascorbic Acid

    Directory of Open Access Journals (Sweden)

    Oputiri Deo

    2013-01-01

    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.

  11. Depletion of ascorbic acid restricts angiogenesis and retards tumor growth in a mouse model.

    Science.gov (United States)

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

    2007-01-01

    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. Here, we show that, not surprisingly, ascorbic acid is necessary for the synthesis of collagen type IV by human endothelial cells and for their effective migration and tube formation on a basement membrane matrix. Furthermore, ascorbic acid depletion in mice incapable of synthesizing ascorbic acid (Gulo(-/-)) dramatically restricts the in vivo growth of implanted Lewis lung carcinoma tumors. Histopathological analyses of these tumors reveal poorly formed blood vessels, extensive hemorrhagic foci, and decreased collagen and von Willebrand factor expression. Our data indicate that ascorbic acid plays an essential role in tumor angiogenesis and growth, and that restriction of ascorbic acid or pharmacological inhibition of prolyl hydroxylase may prove to be novel therapeutic approaches to the treatment of cancer. PMID:17325743

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

    Directory of Open Access Journals (Sweden)

    Sucheta Telang

    2007-01-01

    Full Text Available 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. Here, we show that, not surprisingly, ascorbic acid is necessary for the synthesis of collagen type IV by human endothelial cells and for their effective migration and tube formation on a basement membrane matrix. Furthermore, ascorbic acid depletion in mice incapable of synthesizing ascorbic acid (Gulo-/- dramatically restricts the in vivo growth of implanted Lewis lung carcinoma tumors. Histopathological analyses of these tumors reveal poorly formed blood vessels, extensive hemorrhagic foci, and decreased collagen and von Willebrand factor expression. Our data indicate that ascorbic acid plays an essential role in tumor angiogenesis and growth, and that restriction of ascorbic acid or pharmacological inhibition of prolyl hydroxylase may prove to be novel therapeutic approaches to the treatment of cancer.

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

    DEFF Research Database (Denmark)

    Meyer, Anne S.; Jacobsen, Charlotte

    1996-01-01

    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.

  14. Ascorbic acid study in citrus juice: effect of preservative

    International Nuclear Information System (INIS)

    This paper reports the effect of preservative on ascorbic acid extracted from freshly plucked oranges. Colorimetric method was used for the determination of ascorbic. Determination of some inorganic elements like sodium, potassium and lithium were also determined by flame photometry. The preservative was found to have a beneficial effect on the retention of ascorbic acid, particularly when used in high concentration. Metal content, particularly potassium did no alter significantly during preservation for duration of one month. (author)

  15. The role of ascorbic acid in senile cataract.

    OpenAIRE

    Bensch, K. G.; Fleming, J. E.; Lohmann, W.

    1985-01-01

    The reductone ascorbic acid, present in the crystalline lens in concentrations higher than those of glucose, is capable of undergoing nonenzymatic "browning" in the presence of lenticular proteins. We studied the nonenzymatic browning with ascorbate in model systems employing bovine serum albumin and lens crystallins. When bovine serum albumin, alpha-crystallin, or gamma-crystallin was incubated with [14C]ascorbic acid, the formation of yellow and then brown condensation products appeared to ...

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

    International Nuclear Information System (INIS)

    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

  17. 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

  18. Allosteric modulation of retinal GABA receptors by ascorbic acid

    Science.gov (United States)

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

    2011-01-01

    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

  19. Ascorbic acid conjugates isolated from the phloem of Cucurbitaceae.

    Science.gov (United States)

    Hancock, Robert D; Chudek, John A; Walker, Paul G; Pont, Simon D A; Viola, Roberto

    2008-06-01

    Analysis of phloem exudates from the fruit of Cucurbitaceae revealed the presence of several compounds with UV-visible absorption spectra identical to that of l-ascorbic acid. In Cucurbita pepo L. (zucchini), the compounds could be isolated from phloem exudates collected from aerial parts of the plant but were not detected in whole tissue homogenates. The compounds isolated from the phloem exudates of C. pepo fruit were eluted from strong anion exchange resin in the same fraction as l-ascorbic acid and were oxidised by ascorbate oxidase (E.C. 1.10.3.3). The major compound purified from C. pepo fruit exudates demonstrated similar redox properties to l-ascorbic acid and synthetic 6-O-glucosyl-l-ascorbic acid (6-GlcAsA) but differed from those of 2-O-glucosyl-l-ascorbic acid (2-GlcAsA) isolated from the fruit of Lycium barbarum L. Parent and fragment ion masses of the compound were consistent with hexosyl-ascorbate in which the hexose moiety was attached to C5 or C6 of AsA. Acid hydrolysis of the major C. pepo compound resulted in the formation of l-ascorbic acid and glucose. The purified compound yielded a proton NMR spectrum that was almost identical to that of synthetic 6-GlcAsA. A series of l-ascorbic acid conjugates have, therefore, been identified in the phloem of Cucurbitaceae and the most abundant conjugate has been identified as 6-GlcAsA. The potential role of such conjugates in the long-distance transport of l-ascorbic acid is discussed. PMID:18472116

  20. THE EFFECTS OF ASCORBIC ACID ON MEMBRANE TRANSPORT OF GLUCOSE

    Directory of Open Access Journals (Sweden)

    Zoran Pavlovic

    2004-01-01

    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.

  1. Spectrophotometry determination of irradiated ascorbic acid

    International Nuclear Information System (INIS)

    This work aims at the study of the radiation effects on vitamin C, when irradiated either solid, as a powder, or in an acetic-metaphosforic acid solution, irradiated with Co-60 or electron beam irradiation (EB). Doses of Co-60 ? radiation of 0, 0.05, 0.1, 0.25, 0.5, 1.0, 5.0, 10, 20 and 50 kGy were used for both solid or liquid samples. EB irradiations, with doses of 0, 5, 10, 20, 50, 100, 200 and 300 kGy were only employed for solid state samples. For samples irradiated in solution, a decrease of the UV absorbance as a linear function of dose was shown for doses of 0.05, 0.1, 0.25 and 0.5 kGy remaining constant afterwards. UV spectra of samples irradiated in the solid state and dissolved after irradiation did not change as a function of dose showing no effect of ? or EB irradiation on ascorbic acid in this case. These results point out the importance of the water content on vitamin C stability and suggest several practical considerations that can be drawn on industrial food irradiation. (author). 11 refs., 3 figs., 3 tabs

  2. Polarographic Methods for Determination of Ascorbic Acid in Pharmacetical Preparations

    Directory of Open Access Journals (Sweden)

    Swaroopa Rani N. Gupta

    2014-04-01

    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

  3. Habitual diet and ascorbic acid status in Sudanese camels.

    Science.gov (United States)

    Mohamed, Hasablerasoul E; Alhaidary, Ahmed; Beynen, Anton Christian

    2013-03-01

    There is suggestive evidence that a low status of ascorbic acid in camels enhances their risk for infectious diseases. This study was carried out to find clues as to the role of diet in affecting ascorbic acid status. In a crossover trial with feeding periods of 3 weeks each, six camels (Camelus dromedarius) were fed either a composite of their habitual diet or alfalfa. The simulated habitual diet contained grass (hummra), Acacia mellifera and Blepharis persica. The habitual diet significantly lowered ascorbic acid concentrations in plasma and leukocytes. It is concluded that camels kept on natural desert vegetation may not have optimal disease resistance due to a diet-induced low ascorbic acid status. PMID:23345066

  4. Determination of L- Ascorbic Acid in Plasma by Voltammetric Method

    OpenAIRE

    Behfar, Abdol Azim; Sadeghi, Nafiseh; Jannat, Behrooz; Oveisi, Mohammad Reza

    2010-01-01

    Voltammetric techniques have been considered as important methods among the analytical techniques used for the identification and determination of trace concentrations of many biological molecules such as L-ascorbic acid (AA). L-ascorbic acid is an electro-active molecule, though it is difficult to determine its value directly with a majority of electrodes made of carbon and transition metals, because of electrode surface problems. The present study is based on I-E curves for AA analysis at v...

  5. Ascorbic Acid Supplement During Luteal Phase in IVF

    OpenAIRE

    Griesinger, Georg; Franke, Katharina; Kinast, Cordelia; Kutzelnigg, Alexandra; Riedinger, Sandra; Kulin, Sandor; Kaali, Steven G.; Feichtinger, Wilfried

    2002-01-01

    Purpose: To evaluate the impact of ascorbic acid of different doses as additional support during luteal phase in infertility treatment by means of a prospective, randomized, placebo-controlled, group comparative, double-blind study. Methods: Voluntary daily oral intake of either ascorbic acid (1, 5, or 10 g/day) or Placebo for 14 days after follicle aspiration for IVF-ET procedure. Data was obtained on 620 cases of women, age

  6. L-Ascorbic Acid: A Multifunctional Molecule Supporting Plant Growth and Development

    OpenAIRE

    Gallie, Daniel R.

    2013-01-01

    L-Ascorbic acid (vitamin C) is as essential to plants as it is to animals. Ascorbic acid functions as a major redox buffer and as a cofactor for enzymes involved in regulating photosynthesis, hormone biosynthesis, and regenerating other antioxidants. Ascorbic acid regulates cell division and growth and is involved in signal transduction. In contrast to the single pathway responsible for ascorbic acid biosynthesis in animals, plants use multiple pathways to synthesize ascorbic acid, perhaps re...

  7. The novel Arabidopsis thaliana svt2 suppressor of the ascorbic acid-deficient mutant vtc1-1 exhibits phenotypic and genotypic instability

    OpenAIRE

    Kempinski, Chase F.; Crowell, Samuel V.; Smeeth, Caleb; Barth, Carina

    2013-01-01

    Ascorbic acid is a potent antioxidant that detoxifies reactive oxygen species when plants are exposed to unfavorable environmental conditions. In addition to its antioxidant properties, ascorbic acid and its biosynthetic precursors fulfill a variety of other physiological and molecular functions. A mutation in the ascorbic acid biosynthesis gene VTC1, which encodes GDP-mannose pyrophosphorylase, results in conditional root growth inhibition in the presence of ammonium. To isolate suppresso...

  8. Ascorbic acid: Chemistry, biology and the treatment of cancer?

    OpenAIRE

    Du, Juan; Cullen, Joseph J.; Buettner, Garry R.

    2012-01-01

    Since the discovery of vitamin C, the number of its known biological functions is continually expanding. Both the names ascorbic acid and vitamin C reflect its antiscorbutic properties due to its role in the synthesis of collagen in connective tissues. Ascorbate acts as an electron-donor keeping iron in the ferrous state thereby maintaining the full activity of collagen hydroxylases; parallel reactions with a variety of dioxygenases affect the expression of a wide array of genes, for example ...

  9. Anti-angiogenic effect of high doses of ascorbic acid

    Directory of Open Access Journals (Sweden)

    Ichim Thomas E

    2008-09-01

    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.

  10. [Plasma ascorbic acid: preanalytical factors and new HPLC method].

    Science.gov (United States)

    Flourié, F; Steghens, J-P

    2004-01-01

    We describe a fast ED-HPLC method for ascorbic acid analysis, carried out on a new mixed mode chromatographic column. Due to its functional dodecylsilane group associating a quaternary ammonium, this column is simpler and easier to handle than previous ones because without any counter-ion in the mobile phase. As ascorbic acid and glutathione are very often measured on the same blood sample, it was efficient to validate a common pretreatment solution for ascorbic acid in plasma and glutathione in whole blood. This pretreatment is based on the use of a sulfosalycilic acid, N-ethylmaleimide, EDTA mix recently described. Plasma samples, stored after deproteinisation and without centrifugation, are stable for three weeks at -20 or -80 degrees C. PMID:15217763

  11. ESR Study on Irradiated Ascorbic Acid Single Crystal

    Science.gov (United States)

    Tuner, H.; Korkmaz, M.

    2007-04-01

    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 acid.

  12. 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

  13. The sodium-dependent ascorbic acid transporter family SLC23.

    Science.gov (United States)

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

    2013-01-01

    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

  14. Effect of ascorbic acid supplementation on nitric oxide metabolites and systolic blood pressure in rats exposed to lead

    Directory of Open Access Journals (Sweden)

    Mohammad Amani

    2010-01-01

    Full Text Available Background: Extended exposure to low levels of lead causes high blood pressure in human and laboratory animals. The mechanism is not completely recognized, but it is relatively implicated with generation of free radicals, oxidant agents such as ROS, and decrease of available nitric oxide (NO. In this study, we have demonstrated the effect of ascorbic acid as an antioxidant on nitric oxide metabolites and systolic blood pressure in rats exposed to low levels of lead. Materials and Methods: The adult male Wistar rats weighing 200-250 g were divided into four groups: control, lead acetate (receiving 100 ppm lead acetate in drinking water, lead acetate plus ascorbic acid (receiving 100 ppm lead acetate and 1 g/l ascorbic acid in drinking water, and ascorbic acid (receiving 1 g/l ascorbic acid in drinking water groups. The animals were anesthetized with ketamin/xylazine (50 and 7 mg/kg, respectively, ip and systolic blood pressure was then measured from the tail of the animals by a sphygmomanometer. Nitric oxide levels in serum were measured indirectly by evaluation of its stable metabolites (total nitrite and nitrate (NOc. Results: After 8 and 12 weeks, systolic blood pressure in the lead acetate group was significantly elevated compared to the control group. Ascorbic acid supplementation could prevent the systolic blood pressure rise in the lead acetate plus ascorbic acid group and there was no significant difference relative to the control group. The serum NOc levels in lead acetate group significantly decreased in relation to the control group, but this reduction was not significantly different between the lead acetate plus ascorbic acid group and the control group. Conclusion: Results of this study suggest that ascorbic acid as an antioxidant prevents the lead induced hypertension. This effect may be mediated by inhibition of NOc oxidation and thereby increasing availability of NO.

  15. DOES PROLONGED EXPOSURE OF SOYBEAN PLANTS TO ELEVATED OZONE CAUSE INHIBITION AND/OR INACTIVATION OF THE FOLIAR ASCORBIC ACID SYNTHESIS PATHWAY ENZYMES, GALACTOSE DEHYDROGENASE AND GALACTONO-1,4-DEHYDROGENASE?

    Science.gov (United States)

    Two major enzymes in the green plant leaf cell ascorbic acid (ASC) synthesis pathway are L-galactose dehydrogenase (GALDH) and the terminal enzyme, L-galactono-1,4-dehydrogenase (GLDH). The effect of chronic elevated O3 exposure on mature soybean leaflet GALDH and GLDH activities was estimated in v...

  16. Simultaneous determination of uric acid and ascorbic acid using edge plane pyrolytic graphite electrodes

    OpenAIRE

    Kachoosangi, Rt; Banks, Ce; Compton, Rg

    2006-01-01

    Edge plane pyrolytic graphite electrodes have been applied for the determination of uric acid and ascorbic acid. The separate determination of uric acid was found to produce three linear ranges from 100 nM to 3400 ?M with a detection limit of 30 nM found to be possible. Uric acid detection was also explored in the presence of 200 ?M ascorbic acid where a detection limit of 52 nM was found to be possible. The detection of ascorbic acid in the presence of uric acid was also explored over thre...

  17. Chemical dosimetry by UV spectrophotometry of aqueous ascorbic acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Alian, A.; El-Assay, N.B.; Abdel-Rehim, F.; Amin, N.E.; McLaughlin, W.L.; Roushdy, H.

    1984-01-01

    The decrease in the ultraviolet absorption of aqueous solutions of ascorbic acid brought about by large doses of gamma radiation has been investigated as a means of developing a new chemical dosimeter. Because of spontaneous ring opening under various conditions after dissolution in water, some additives were examined as possible stabilizers against such denaturing of aqueous ascorbic acid. At an ascorbic acid concentration of 10/sup -4/ M, either 1 to 2% glycine or 0.2 M NaCl was found to be a good stabilizer. A mechanism of radiation chemistry has been proposed based on hydroxyl radical and hydroxyl adduct intermediates, leading to dehydroascorbic acid through the ascorbate complex. The optimum dosimeter solution covers an absorbed dose range approx. 50 to 350 Gy, when measured at 264 nm wavelength. The G-values for dehydroascorbic acid production were determined to be 2.94 +- 0.33 and 2.43 +- 0.11 (100 eV)/sup -1/, with glycine and NaCl used respectively as stabilizers.

  18. Synergistic protective effects of ceftriaxone and ascorbic acid against subacute deltamethrin-induced nephrotoxicity in rats.

    Science.gov (United States)

    Abdel-Daim, Mohamed M; El-Ghoneimy, Ashraf

    2015-03-01

    Abstract Deltamethrin (DLM) is a synthetic class II pyrethroid acaricide and insecticide widely used for veterinary and agricultural purposes. However, its animal and human exposure leads to nephrotoxicity. Our experimental objective was to evaluate protective effects of ceftriaxone and/or ascorbic acid against DLM-induced renal injury in male Wistar albino rats. DLM-treated animals revealed significant alterations in serum biochemical parameters related to renal injury; urea, uric acid and creatinine. There was a significant increase in renal lipid peroxidation and a significant inhibition in antioxidant biomarkers. Moreover, DLM significantly reduced serum acetylcholinesterase (AChE) activity. In addition, It induced serum and kidney tumor necrosis factor-? (TNF-?). Both ceftriaxone and ascorbic acid protect against DLM-induced biochemical alterations in serum and renal tissue when used alone or in combination along with DLM-intoxication. Furthermore, both ceftriaxone and ascorbic acid produced synergetic nephroprotective and antioxidant effects. Therefore, it could be concluded that ceftriaxone and/or ascorbic acid administration able to minimize the toxic effects of DLM through their free radical-scavenging and potent antioxidant activity. PMID:25691087

  19. A chronoamperometric screen printed carbon biosensor based on alkaline phosphatase inhibition for W(IV) determination in water, using 2-phospho-L-ascorbic acid trisodium salt as a substrate.

    Science.gov (United States)

    Alvarado-Gámez, Ana Lorena; Alonso-Lomillo, María Asunción; Domínguez-Renedo, Olga; Arcos-Martínez, María Julia

    2015-01-01

    This paper presents a chronoamperometric method to determine tungsten in water using screen-printed carbon electrodes modified with gold nanoparticles and cross linked alkaline phosphatase immobilized in the working electrode. Enzymatic activity over 2-phospho-l-ascorbic acid trisodium salt, used as substrate, was affected by tungsten ions, which resulted in a decrease of chronoamperometric current, when a potential of 200 mV was applied on 10 mM of substrate in a Tris HCl buffer pH 8.00 and 0.36 M of KCl. Calibration curves for the electrochemical method validation, give a reproducibility of 5.2% (n = 3), a repeatability of 9.4% (n = 3) and a detection limit of 0.29 ± 0.01 µM. Enriched tap water, purified laboratory water and bottled drinking water, with a certified tungsten reference solution traceable to NIST, gave a recovery of 97.1%, 99.1% and 99.1% respectively (n = 4 in each case) and a dynamic range from 0.6 to 30 µM. This study was performed by means of a Lineweaver-Burk plot, showing a mixed kinetic inhibition. PMID:25621602

  20. Effect of Helicobacter pylori and its eradication on gastric juice ascorbic acid.

    OpenAIRE

    Banerjee, S.; Hawksby, C.; Miller, S.; Dahill, S.; Beattie, A. D.; Mccoll, K. E.

    1994-01-01

    The presence of ascorbic acid in gastric juice may protect against gastric carcinoma and peptic ulceration. This study examined the effect of Helicobacter pylori (H pylori) on the secretion of ascorbic acid into gastric juice by measuring fasting plasma and gastric juice ascorbic acid concentrations in patients with and without the infection and also before and after its eradication. Gastric juice ascorbic acid concentrations in 19 H pylori positive patients were significantly lower (median 2...

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

    Directory of Open Access Journals (Sweden)

    Prashansa Sharma

    2014-09-01

    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.

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

    Directory of Open Access Journals (Sweden)

    LI Gang

    2013-02-01

    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.

  3. Polarographic Methods for Determination of Ascorbic Acid in Pharmacetical Preparations

    OpenAIRE

    Gupta, Swaroopa Rani N.

    2014-01-01

    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...

  4. Stimulation of cell division in the rat by NaCl, KCl, MgCl2, and CaCl2, and inhibition of the sodium chloride effect on the glandular stomach by ascorbic acid and beta-carotene.

    Science.gov (United States)

    Lugli, S M; Lutz, W K

    1999-01-01

    Three questions associated with the stimulation of cell division by chloride salts have been investigated: (i) whether cations other than sodium show a similar effect, (ii) whether vitamins can have a preventive activity, and (iii) whether subchronic treatment with sodium chloride in the diet is also effective. Male Fischer 344 rats were given solutions of the chloride salts of sodium, potassium, magnesium, and calcium by oral gavage. Water was used for control. After 4 h, a 24-h osmotic minipump containing 5-bromo-2'-deoxyuridine was implanted subcutaneously. The forestomach and glandular stomach, as well as liver and bladder were analyzed immunohistochemically 24 h later for the proportion of cells in S phase as an indicator of the rate of replicative DNA synthesis. For both the forestomach and the glandular stomach, potassium was as potent as sodium, and the divalent cations Mg and Ca were even more potent on a molar basis. Supplementation of the diet with ascorbic acid (2 g/kg food) or beta-carotene (12.5 mg/kg food) for 1 week before gavage of the sodium chloride solution resulted in an inhibition of the stimulation of cell division. A putative tumor-chemopreventive activity of the two vitamins might therefore not only rely on their antioxidative properties but may include effects on the cell cycle. A 4-week treatment with a sodium chloride supplement in the diet (2% and 4% supplement) resulted in a significant stimulation of cell division not only in both parts of the stomach and in the bladder (with the 4% supplement) but also in the liver (even with the 2% supplement). Sodium-chloride-stimulated cell turnover therefore is a sustained effect. PMID:10235475

  5. Ascorbic Acid Prevents Oxidant-induced Increases in Endothelial Permeability

    OpenAIRE

    May, James M.; Qu, Zhi-chao

    2010-01-01

    Oxidative stress acutely increases the permeability of the vascular endothelium to large molecules that would not otherwise cross the barrier. Ascorbic acid is an antioxidant that tightens the endothelial permeability barrier, so we tested whether it might also prevent the increase in endothelial permeability due to cellular oxidative stress. Treatment of EA.hy926 endothelial cells cultured on filter inserts with H2O2, menadione, and buthionine sulfoximine increased endothelial permeability t...

  6. Effect of rosemary, echinacea, green tea extracts and ascorbic acid on broiler meat quality.

    Science.gov (United States)

    Mirshekar, R; Dastar, B; Shabanpour, B

    2009-08-01

    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 degrees 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. PMID:19943463

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

    Directory of Open Access Journals (Sweden)

    R. Mirshekar

    2009-01-01

    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.

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

    DEFF Research Database (Denmark)

    Zhou, A; Matsumoto, T

    1990-01-01

    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.

  9. Ascorbic acid prevents nonreceptor specific binding of [3H]-5-hydroxytryptamine to bovine cerebral cortex membranes

    International Nuclear Information System (INIS)

    [3H]-5-Hydroxytryptamine ([3H]-5-HT) decomposes rapidly when exposed to air in solution at physiological pH if antioxidants are not present. The decomposition products appear to bind to two saturable sites on brain membranes (apparent Kd values = 1-2 and 100-1000 nM). This binding mimics ''specific'' ligand/receptor binding in that it is inhibited by 10 microM unlabeled 5-HT. This inhibition is not competitive, but rather is due to the prevention of [3H]-5-HT breakdown by excess unlabeled 5-HT. Unlike genuine ligand/receptor binding, the binding of [3H]-5-HT breakdown products is essentially irreversible and does not display a tissue distribution consistent with binding to authentic 5-HT receptors. [3H]-5-HT decomposition can be eliminated by the inclusion of 0.05 to 5 mM ascorbic acid. At these concentrations ascorbic acid is not deleterious to reversible [3H]-5-HT binding. When [3H] 5-HT exposure to air occurs in the presence of brain membranes, the apparent antioxidant activity of brain membranes themselves affords protection against [3H]-5-HT degradation equal to ascorbic acid. This protection is effective below final [3H]-5-HT concentrations of 10 nM. Above 10 nM [3H]-5-HT, addition of ascorbic acid or other antioxidants is necessary to avoid the occurrence of additional low affinity (apparent Kd = 15-2000 nM) binding sites that are specific but nonetheleding sites that are specific but nonetheless irreversible. When care is taken to limit [3H]-5-HT oxidation, the only reversible and saturable specific binding sites observed are of the 5-HT1 high affinity (Kd = 1-2 nM) type. Radioligand oxidation artifacts may be involved in previous reports of low affinity (Kd = 15-250 nM) [3H]-5-HT binding sites in brain membrane preparations

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

    OpenAIRE

    "Oveisi MR; Sadeghi N.

    2001-01-01

    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 an...

  11. Inhibitory Effect of Ascorbic Acid on the Proliferation and Invasion of Hepatoma Cells in Culture

    OpenAIRE

    Hirakawa, Nobuhiro; Miura, Yutaka; Yagasaki, Kazumi

    2005-01-01

    Effect of ascorbic acid (AsA) on the proliferation and invasion of rat ascites hepatoma AH109A cells was investigated by measuring [3H]thymidine incorporation into acid-insoluble fraction of the cells and by co-culturing the hepatoma cells with rat mesentery-derived mesothelial cells, respectively. AsA suppressed the invasion of AH109A cells in a dose-dependent manner at concentrations of 62.5–500 ?M, while it inhibited the proliferation of the cells at higher concentrations of 250 and 50...

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

    Directory of Open Access Journals (Sweden)

    Mirsad Salki?

    2007-12-01

    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.

  13. Antioxidant properties of ascorbic acid in bulk oils at different relative humidity.

    Science.gov (United States)

    Kim, Ji Young; Kim, Mi-Ja; Yi, Bora; Oh, Sumi; Lee, JaeHwan

    2015-06-01

    The effects of relative humidity (RH) on the antioxidant properties of ascorbic acid (10, 20, 42, and 84ppm) were investigated in stripped corn oils stored at 60°C. The degree of oxidation in oils was determined by analysing headspace oxygen content and conjugated dienoic acids. The oxidative stability of bulk oils without addition of ascorbic acid was significantly different depending on the RH. As the concentration of ascorbic acid increased from 10 to 84ppm, oxidative stability increased significantly irrespective of RH (p<0.05). Generally, oils containing ascorbic acid at low RH had higher oxidative stability after storage at 60°C than those at high RH. The antioxidant properties of ascorbic acid were greatly influenced by both the moisture content in the oil and the ascorbic acid concentration. PMID:25624237

  14. The novel Arabidopsis thaliana svt2 suppressor of the ascorbic acid-deficient mutant vtc1-1 exhibits phenotypic and genotypic instability [v1; ref status: indexed, http://f1000r.es/o2

    OpenAIRE

    Kempinski, Chase F.; Crowell, Samuel V.; Caleb Smeeth; Carina Barth

    2013-01-01

    Ascorbic acid is a potent antioxidant that detoxifies reactive oxygen species when plants are exposed to unfavorable environmental conditions. In addition to its antioxidant properties, ascorbic acid and its biosynthetic precursors fulfill a variety of other physiological and molecular functions. A mutation in the ascorbic acid biosynthesis gene VTC1, which encodes GDP-mannose pyrophosphorylase, results in conditional root growth inhibition in the presence of ammonium. To isolate suppressors ...

  15. Cytotoxicity of ascorbate, lipoic acid, and other antioxidants in hollow fibre in vitro tumours

    OpenAIRE

    Casciari, J. J.; Riordan, N. H.; Schmidt, T. L.; Meng, X. L.; Jackson, J. A.; Riordan, H. D.

    2001-01-01

    Vitamin C (ascorbate) is toxic to tumour cells, and has been suggested as an adjuvant cancer treatment. Our goal was to determine if ascorbate, in combination with other antioxidants, could kill cells in the SW620 hollow fibre in vitro solid tumour model at clinically achievable concentrations. Ascorbate anti-cancer efficacy, alone or in combination with lipoic acid, vitamin K 3, phenyl ascorbate, or doxorubicin, was assessed using annexin V staining and standard survival assays. 2-day treatm...

  16. Purification of the alkaloid lycorine and simultaneous analysis of ascorbic acid and lycorine by micellar electrokinetic capillary chromatography.

    Science.gov (United States)

    Davey, M W; Persiau, G; De Bruyn, A; Van Damme, J; Bauw, G; Van Montagu, M

    1998-03-01

    The pyrrolophenanthridine alkaloid lycorine has frequently been used as a specific inhibitor to help elucidate the function of ascorbic acid (vitamin C) in a wide range of biological processes. It was recently reported that this function can be exercised by inhibiting the activity of L-galactono-1,4-lactone dehydrogenase, the terminal enzyme of ascorbic acid biosynthesis, although working with the purified enzyme, we have been unable to repeat this result. Here, we present a procedure for the purification and analysis of lycorine by high-performance liquid chromatography from two Crinum species and describe for the first time a method that allows the simultaneous analysis of ascorbic acid and lycorine in tissue extracts of Crinum asiaticum by micellar electrokinetic chromatography. PMID:9512776

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

    Science.gov (United States)

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

    2015-04-01

    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.

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

    International Nuclear Information System (INIS)

    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 ?g ml-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

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

    Science.gov (United States)

    Bellocco, E.; Barreca, D.; Laganà, G.; Leuzzi, U.; Migliardo, F.; Torre, R. La; Galli, G.; Galtieri, A.; Minutoli, L.; Squadrito, F.

    2008-04-01

    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 t1/2 (half life time), as determined by high performance liquid chromatography (HPLC).

  20. Enzyme-mimetic effects of gold@platinum nanorods on the antioxidant activity of ascorbic acid

    Science.gov (United States)

    Zhou, Yu-Ting; He, Weiwei; Wamer, Wayne G.; Hu, Xiaona; Wu, Xiaochun; Lo, Y. Martin; Yin, Jun-Jie

    2013-01-01

    Au@Pt nanorods were prepared by growing platinum nanodots on gold nanorods. Using electron spin resonance (ESR), we determined that the mechanisms for oxidation of ascorbic acid (AA) by Au@Pt nanorods and ascorbic acid oxidase (AAO) were kinetically similar and yielded similar products. In addition we observed that Au@Pt nanorods were stable with respect to temperature and pH. Using UV-VIS spectroscopy, the apparent kinetics of enzyme-mimetic activity of Au@Pt nanorods were studied and compared with the activity of AAO. With the help of ESR, we found that Au@Pt nanorods did not scavenge hydroxyl radicals but inhibited the antioxidant ability of AA for scavenging hydroxyl radicals produced by photoirradiating solutions containing titanium dioxide and zinc oxide. Moreover, the Au@Pt nanorods reduced the ability of AA to scavenge DPPH radicals and superoxide radicals. These results demonstrate that Au@Pt nanorods can reduce the antioxidant activity of AA. Therefore, it is necessary to consider the effects of using Pt nanoparticles together with other reducing agents or antioxidants such as AA due to the oxidase-like property of Au@Pt nanorods.Au@Pt nanorods were prepared by growing platinum nanodots on gold nanorods. Using electron spin resonance (ESR), we determined that the mechanisms for oxidation of ascorbic acid (AA) by Au@Pt nanorods and ascorbic acid oxidase (AAO) were kinetically similar and yielded similar products. In addition we observed that Au@Pt nanorods were stable with respect to temperature and pH. Using UV-VIS spectroscopy, the apparent kinetics of enzyme-mimetic activity of Au@Pt nanorods were studied and compared with the activity of AAO. With the help of ESR, we found that Au@Pt nanorods did not scavenge hydroxyl radicals but inhibited the antioxidant ability of AA for scavenging hydroxyl radicals produced by photoirradiating solutions containing titanium dioxide and zinc oxide. Moreover, the Au@Pt nanorods reduced the ability of AA to scavenge DPPH radicals and superoxide radicals. These results demonstrate that Au@Pt nanorods can reduce the antioxidant activity of AA. Therefore, it is necessary to consider the effects of using Pt nanoparticles together with other reducing agents or antioxidants such as AA due to the oxidase-like property of Au@Pt nanorods. Electronic supplementary information (ESI) available: Ascorbic acid oxidase activity of Pt NPs and the effects of Au@Pt nanorods on hydroxyl radicals generated from the Fenton reactions and TiO2 exposed to UV radiation. See DOI: 10.1039/c2nr33072e

  1. Efficiency of ascorbic acid and ?-rays to ameliorate the quality of ready-to-eat baked bolti fish fillets

    International Nuclear Information System (INIS)

    Ascorbic acid (vitamin C) is a reducing agent, inhibits oxidative reactions developed in cold-storage Bolti (Tilapia nilotica) fish. It is the most popular fish repasts in Egypt. To determine the influence of ascorbic acid on cooking (roasting) and irradiated fish fillets to extend their storage-time in refrigerators, 3 patches of fish fillets were prepared; control (0 kGy), ascorbic acid plus 2.5 kGy and ascorbic acid plus 4 kGy and were tested for bacteriological examination, chemical analysis and sensory evaluation at 0, 1, 2 and 3 weeks of cold storage at 5±1 degree C. The bacteriological examinations were total aerobic plate counts, psychotropic bacterial counts, Enterobacteriaceae counts, total mould and yeast counts and microbial pathogens counts (Salmonella and Vibrio species). The chemical analyses were thiobarbituric acid reactive substances (TBARS), inosine 5-monophosphate (IMP) concentration, hypoxanthine (HX) concentration, ph figure, total volatile nitrogen (TVN) and total trimethylamine nitrogen (TMA-N). The sensory evaluation was (texture and odour factors) of the cold-storage Bolti fish fillets samples. The results revealed that aerobically packed fish fillets samples treated with ascorbic acid plus 4 kGy after cooking had satisfied bacteriological, chemical and organoleptical trails. Conclusion: using of baking, irradiation combined with natural antioxidant nd refrigeration could reduce the energy requirements for freezing and costs for the marketins for freezing and costs for the marketing of ready- to-eat fish repasts. Recommendation: combination effects of ?-irradiation plus ascorbic acid in processing fish fillets help to preserve its quality. The possible strategies for improving fish fillets quality and acceptability are discussed

  2. Ionizing radiation effects on the ascorbic acid content in maize seedlings, and the effect of ascorbic acid on the lipid oxidation

    International Nuclear Information System (INIS)

    A polarographic determination was made of the content of ascorbic acid in maize sprouts of radio-sensitive and radio-resistant strains irradiated with Co60 gamma radiation. After a 10 krad dose of radiation, the ascorbic acid content dropped (by 60 and 30 per cent respectively), but increased in both strains by 1.5 to 1.6 times compared with the control group after doses of 2 and 4 krad. The content of aldehyde, the formation of which was used to determine the action of ascorbic acid, increased when ascorbic acid and FeCl2 were added to the water-soluble products of oleic acid and products excreted by the maize sprouts. (author)

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

    Science.gov (United States)

    Wang, Zhihua; Teng, Xu; Lu, Chao

    2012-04-21

    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

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

    Science.gov (United States)

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

    2014-03-01

    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.

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

    International Nuclear Information System (INIS)

    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)

  6. Ascorbic acid levels of aqueous humor of dogs after experimental phacoemulsification.

    Science.gov (United States)

    De Biaggi, Christianni P; Barros, Paulo S M; Silva, Vanessa V; Brooks, Dennis E; Barros, Silvia B M

    2006-01-01

    Phacoemulsification has been successfully employed in humans and animals for lens extraction. This ultrasonic extracapsular surgical technique induces hydroxyl radical formation in the anterior chamber, which accumulates despite irrigation and aspiration. In this paper we determined the total antioxidant status of aqueous humor after phacoemulsification by measuring aqueous humor ascorbic acid levels. Mixed-breed dogs (n = 11; weighing about 10 kg) with normal eyes as determined by slit-lamp biomicroscopy, applanation tonometry, and indirect ophthalmoscopy had phacoemulsification performed in one eye with the other eye used as a control. Samples of aqueous humor were obtained by anterior chamber paracentesis before surgery and at days 1, 2, 3, 7, and 15 after surgery. Total aqueous humor antioxidant status was inferred from the capacity of aqueous humor to inhibit free radical generation by 2,2-azobis (2-amidopropane) chlorine. Ascorbic acid concentrations were measured by high-pressure liquid chromatography with UV detection. Protein content was determined with the biuret reagent. Statistical analysis was performed by anova followed by the paired t-test. Total antioxidant capacity was reduced from 48 to 27 min during the first 24 h with a gradual increase thereafter, remaining statistically lower than the control eye until 7 days postoperatively. Reduced levels of ascorbic acid followed this reduction in antioxidant capacity (from 211 to 99 microm after 24 h), remaining lower than the control eye until 15 days postoperatively. Protein concentration in aqueous humor increased from 0.62 mg/mL to 30.8 mg/mL 24 h after surgery, remaining statistically lower than the control eye until 15 days postoperatively. Paracentesis alone did not significantly alter the parameters measured. These results indicate that after phacoemulsification, the aqueous humor ascorbic acid levels and antioxidant defenses in aqueous humor are reduced, indirectly corroborating free radical production in the anterior chamber as a result of phacoemulsification. The inflammatory process consequent to the surgical procedure demonstrated by increased protein content in aqueous humor can also contribute to free radical production and ascorbic acid consumption. PMID:16939457

  7. 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

  8. Plant resistance mechanisms to air pollutants: rhythms in ascorbic acid production during growth under ozone stress

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E.H. (Climate Stress Laboratory, USDA, ARS, Beltsville, MD (United States))

    1991-01-01

    Relationships between ozone (O3) tolerance and leaf ascorbic acid concentrations in O3-susceptible (O3-S) 'Hark' and O3-resistant (O3-R) 'Hood' soybean, Glycine max (L.) Merr., cultivars were examined with high-performance liquid chromatography (HPLC). Leaf samples were analyzed at 4 intervals during a 24 h period. Soybean cultivars grown in the greenhouse with charcoal filtered (CF) and nonfiltered (NF) air showed daily oscillations in ascorbic acid production. Highest ascorbic acid levels in leaves during light coincided with highest concentrations of photochemical oxidants in the atmosphere at 2:00 p.m. The resistant genotype produced more ascorbic acid in its trifoliate leaves than did the corresponding susceptible genotype. Under CF air (an O3-reduced environment) O3-S and O3-R cultivars showed rhythms in ascorbic acid production. In NF air (an O3 stress environment) the O3-R cultivar alone showed rhythms in ascorbic acid production. Results indicated that superior O3 tolerance in the Hood soybean cultivar (compared with Hark) was associated with a greater increase in endogenous levels of ascorbic acid. Ascorbic acid may scavenge free radicals and thereby protect cells from injury by O3 or other oxyradical products. Plants defend themselves against photochemical oxidant stress, such as O3, by several mechanisms. Experimental evidence indicates that antioxidant defense systems existing in plant tissues may function to protect cellular components from deleterious effects of photochemical oxidants through endogenous and exogenous controls.

  9. A modified ninhydrin reagent using ascorbic acid instead of potassium cyanide.

    Science.gov (United States)

    Yokoyama, Sadaji; Hiramatsu, Jun-Ichi

    2003-01-01

    The use of a modified ninhydrin reagent using ascorbic acid instead of potassium cyanide was investigated for the photometric determination of amino acids. It has been found possible to obtain an almost stoichiometric reaction for glutamic acid with a quantitative yield of "Ruhemann's purple", the end-product of the reaction, using ascorbic acid as a safe and economical reducing agent. The modified ninhydrin reagent was composed of 0.5 g of ninhydrin, and 15 mg of ascorbic acid in 60 ml of methyl cellosolve. PMID:16233394

  10. Environmental stress sensitivity of an ascorbic acid-deficient Arabidopsis mutant.

    OpenAIRE

    Conklin, P. L.; Williams, E. H.; Last, R. L.

    1996-01-01

    L-ascorbic acid (vitamin C) is a powerful reducing agent found in millimolar concentrations in plants, and is proposed to play an important role in scavenging free radicals in plants and animals. However, surprisingly little is known about the role of this antioxidant in plant environmental stress adaptation or ascorbate biosynthesis. We report the isolation of soz1, a semi-dominant ozone-sensitive mutant that accumulates only 30% of the normal ascorbate concentration. The results of genetic ...

  11. 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)

  12. CITOGENETICS EFFECTS INDUCED BY THE ASCORBIC ACID TREATMENT OF LARIX DECIDUA MILL. SSP. CARPATICA AND PICEA ABIES (L.) KARST

    OpenAIRE

    Ion Bara; Elena-Cristina Rosu; Felicia Vlad-Rusen; Ioana Ieremia

    2006-01-01

    The paper present the influence of ascorbic acid upon the mitotic division of Larix decidua Mill ssp. carpatica and Picea abies (L.) Karst. The treatment is applied of two variants, germinated seed in ascorbic acid (variantA)and germinated seeds in disttilate water, than treated with ascorbic acid in 3 concentrations (variant B).

  13. Study of Polymorph Prediction For L-Ascorbic Acid

    Directory of Open Access Journals (Sweden)

    Dilhan M. Kalyon

    2005-12-01

    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.

  14. A flexible micro biofuel cell utilizing hydrogel containing ascorbic acid

    Science.gov (United States)

    Goto, Hideaki; Fukushi, Yudai; Nishioka, Yasushiro

    2014-11-01

    This paper reports on a biofuel cell with a dimension of 13×24 mm2 fabricated on a flexible polyimide substrate. I its porous carbon-coated platinum (Pt) electrodes of 3 mm in width and 10 mm in length were fabricated using photolithography and screen printing techniques. Porous carbon was deposited by screen printing of carbon black ink on the Pt electrode surfaces in order to increase the effective electrode surface area and to absorb more enzymes on the electrode surfaces. It utilizes a solidified ascorbic acid (AA) aqueous solution in an agarose hydrogel to increase the portability. The maximum power and power density for the biofuel cell with the fuel unit containing 100 mM AA were 0.063 ?W and 0.21 ?W/cm2 at 0.019 V, respectively.

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

    OpenAIRE

    Mirsad Salki?; Husejin Keran; Midhat Jaši?

    2009-01-01

    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 devia...

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

    Directory of Open Access Journals (Sweden)

    Oveisi MR

    2001-07-01

    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.

  17. Total phenols, ascorbic acid, b-carotene and lycopene in Portuguese wild edible mushrooms and their antioxidant activities

    OpenAIRE

    Barros, Lillian; Ferreira, Maria Joa?o; Queiro?s, Bruno; Ferreira, Isabel C. F. R.; Baptista, Paula

    2007-01-01

    The antioxidant activities of three Portuguese wild edible mushroom species, Leucopaxillus giganteus, Sarcodon imbricatus, andAgaricus arvensis, were evaluated. Methanolic extracts were screened for their reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicalscavenging capacity, inhibition of erythrocytes hemolysis and antioxidant activity using the b-carotene linoleate model system. The amounts of ascorbic acid, b-carotene and lycopene found in the mushroom extracts were very ...

  18. 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

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

    International Nuclear Information System (INIS)

    Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% ?-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+?-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

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

    Science.gov (United States)

    Ahn, D. U.; Nam, K. C.

    2004-09-01

    Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% ?-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+?-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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-10-01

    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.

  2. Ascorbic acid and striatal transport of [3H]1-methyl-4-phenylpyridine (MPP+) and [3H]dopamine

    International Nuclear Information System (INIS)

    The inhibition of uptake of [3H]dopamine and [3H]1-methyl-4-phenylpyridine (MPP+) was examined in mouse striatal synaptosomal preparations. Kinetic analysis indicated that ascorbic acid is a noncompetitive inhibitor of [3H]MPP+ uptake. No inhibition of [3H]dopamine uptake is observed. The dopamine uptake blockers, GBR-12909, cocaine, and mazindol strongly inhibit (IC50 3H]dopamine and [3H]MPP+ transport. Nicotine, its metabolites, and other tobacco alkaloids are weak inhibitors except 4-phenylpyridine and lobeline, which are moderate inhibitors of both [3H]dopamine and [3H]MPP+ uptake. These similarities in potencies are in agreement with the suggestion that [3H]MPP+ and [3H] are transported by the same carrier. The differences observed in the alteration of dopaminergic transport and mazindol binding by ascorbic acid suggest that ascorbic acid's effects on [3H]MPP+ transport are related to translocation and/or dissociation processes occurring subsequent to the initial binding event

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

    OpenAIRE

    Antesar Elmagirbi; Hermin Sulistyarti; Atikah Atikah

    2012-01-01

    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 ...

  4. Ascorbic Acid Determination in Commercial Fruit Juice Samples by Cyclic Voltammetry

    OpenAIRE

    Slawomir Kalinowski; Aurelia Magdalena Pisoschi; Andrei Florin Danet

    2008-01-01

    A method was developed for assessing ascorbic acid concentration in commercial fruit juice by cyclic voltammetry. The anodic oxidation peak for ascorbic acid occurs at about 490 mV on a Pt disc working electrode (versus SCE). The influence of the potential sweep speed on the peak height was studied. The obtained calibration graph shows a linear dependence between peak height and ascorbic acid concentration in the domain (0.1–10 mmol·L?1). The equation of the calibration graph was y = 6.3...

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

    OpenAIRE

    Mirsad Salki?; Husejin Keran; Midhat Jaši?

    2007-01-01

    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 determ...

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

    OpenAIRE

    Cvetkovi? Biljana R.; Malbaša Radomir V.; Lon?ar Eva S.; Nježi? Zvonko B.; Šimurina Olivera; Filip?ev Bojana; Tepi? Aleksandra

    2012-01-01

    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 ...

  7. Reductive dissolution of magnetite by ascorbic acid in presence of chelating agents

    International Nuclear Information System (INIS)

    The kinetics of the dissolution of magnetite (Fe3O4) by ascorbic acid alone and ascorbic acid in presence of different chelating agents have been studied at different acid concentrations and chelating agent concentrations and as a function of pH. The overall rate of reaction is dependent on the instantaneous surface area of the magnetite particles and the probable reaction mechanism involves electron transfer from ascorbate anion to protonated and or chelated ?FeIII sites on the surface of the magnetite particles. (author). 7 refs., 5 figs

  8. Low temperature storage affects the ascorbic acid metabolism of cherry tomato fruits.

    Science.gov (United States)

    Tsaniklidis, Georgios; Delis, Costas; Nikoloudakis, Nikolaos; Katinakis, Panagiotis; Aivalakis, Georgios

    2014-11-01

    Tomato fruits are an important source of l-Ascorbic acid, which is an essential compound of human diet. The effect of the widespread practice of cold storing (5-10 °C) tomato fruits was monitored to determine its impact on the concentration and redox status of l-Ascorbic acid. Total l-Ascorbic acid levels were well maintained in both attached fruits and cold treated fruits, while in other treatments its levels were considerably reduced. However, low temperature storage conditions enhanced the expression of most genes coding for enzymes involved in l-Ascorbic acid biosynthesis and redox reactions. The findings suggest that the transcriptional up-regulation under chilling stress conditions of most genes coding for l-Ascorbic acid biosynthetic genes galactono-1,4-lactone dehydrogenase, GDP-d-mannose 3,5-epimerase but also for the isoenzymes of ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase enzyme, glutathione reductase that are strongly correlated to the l-Ascorbic redox status. Moreover, fruits stored at 10 °C exhibited higher levels of transcript accumulation of MDHAR2, DHAR1, DHAR2, GR1 and GR2 genes, pointing to a better ability to manage chilling stress in comparison to fruits stored at 5 °C. PMID:25282013

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

    International Nuclear Information System (INIS)

    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)

  10. Microchip electrophoresis with chemiluminescence detection for assaying ascorbic acid and amino acids in single cells

    OpenAIRE

    Zhao, Shulin; Huang, Yong; Liu, Yi-ming

    2009-01-01

    A method based on microchip electrophoresis (MCE) with chemiluminescence (CL) detection was developed for the determination of ascorbic acid (AA) and amino acids including tryptophan (Trp), glycine (Gly) and alanine (Ala) present in single cells. Cell injection, loading, lysing, electrophoretic separation, and CL detection were integrated onto a simple cross microfluidic chip. A single cell was loaded in the cross intersection by electrophoretic means through applying a set of potentials at t...

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

    Directory of Open Access Journals (Sweden)

    Abbasi

    2008-01-01

    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.

  12. Glutathione-ascorbic acid redox cycle and thioredoxin reductase activity in the digestive tract of Leptinotarsa decemlineata (Say).

    Czech Academy of Sciences Publication Activity Database

    Krishnan, Natraj; Kodrík, Dalibor; Kludkiewicz, Barbara; Sehnal, František

    2009-01-01

    Ro?. 39, ?. 3 (2009), s. 180-188. ISSN 0965-1748 R&D Projects: GA ?R(CZ) GA522/06/1591; GA ?R GA522/07/0788 Institutional research plan: CEZ:AV0Z50070508 Keywords : ascorbate/ascorbic acid * ascorbate peroxidase * glutathione-ascorbic acid redox cycle Subject RIV: CE - Biochemistry Impact factor: 3.117, year: 2009

  13. Ascorbic Acid Determination in Natural Orange Juice: As a Teaching Tool of Coulometry and Polarography.

    Science.gov (United States)

    Bertotti, Mauro; And Others

    1995-01-01

    Describes an experiment designed to determine ascorbic acid concentrations in natural orange juice. The experiment is used with undergraduate pharmacy students to allow understanding of the principles of operation of the coulometer and polarograph. (DDR)

  14. A green method for the synthesis of Copper Nanoparticles using L-ascorbic acid

    Scientific Electronic Library Online (English)

    Asim, Umer; Shahid, Naveed; Naveed, Ramzan; Muhammad Shahid, Rafique; Muhammad, Imran.

    2014-09-01

    Full Text Available Chemical Reduction technique was employed to prepared highly stable and dispersed Copper nanoparticles using L-Ascorbic Acid (Vitamin C) as reducing as well as capping agent. In this technique, cupric chloride was used as precursor. The effects of different molar ratios of L-Ascorbic Acid on the con [...] centration and size of copper nanoparticles were studied. The Copper nanoparticles were characterized by X-Ray Diffraction, Atomic Absorption Spectrometry, and Fourier Transform Infrared Spectrometry. The results show that with the increase in the molar ratio of L-ascorbic acid the concentration of Copper nanoparticles were also increased. The average particles size of copper nanoparticle was found in the range of 50-60 nm. The product was kept in ambient conditions for three month but no sedimentation or separation was observed. The use of ascorbic acid makes the process a non-toxic, cost effective and environmental friendly green method.

  15. Role of ascorbic acid on tyrosine hydroxylase activity in the adrenal gland of guinea pig

    International Nuclear Information System (INIS)

    The decrease of tyrosine hydroxylase activity in adrenal homogenate in scurvy was recovered after the administration of ascorbic acid. The causes of the increase in the enzyme activity after the administration of ascorbic acid have been studied. 1. No significant elevation in the enzyme activity was observed after the administration of reserpine to the scorbutic guinea pig. 2. A dose of metal chelating agent, ?, ?'-dipyridyl, prevented the ascorbic acid-induced or reserpine-induced increase in enzyme activity in the scorbutic and the nonscorbutic guinea pigs, respectively. 3. Tyrosine hydroxylase activity was partially recovered by the administration of FeSO4 to the scorbutic guinea pig. From these results, it became clear that the induction of tyrosine hydroxylase which was not observed in scurvy was due to the deficiency of Fe2+. These results suggested that ascorbic acid affected the induction of this enzyme via Fe2+. (auth.)

  16. Development of Calibration and Standard Addition Polarographic Determination of Ascorbic Acid

    Directory of Open Access Journals (Sweden)

    Swaroopa Rani N. Gupta

    2015-04-01

    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

  17. Ascorbic Acid as a Standard for Iodometric Titrations. An Analytical Experiment for General Chemistry

    Science.gov (United States)

    Silva, Cesar R.; Simoni, Jose A.; Collins, Carol H.; Volpe, Pedro L. O.

    1999-10-01

    Ascorbic acid is suggested as the weighable compound for the standardization of iodine solutions in an analytical experiment in general chemistry. The experiment involves an iodometric titration in which iodine reacts with ascorbic acid, oxidizing it to dehydroascorbic acid. The redox titration endpoint is determined by the first iodine excess that is complexed with starch, giving a deep blue-violet color. The results of the titration of iodine solution using ascorbic acid as a calibration standard were compared with the results acquired by the classic method using a standardized solution of sodium thiosulfate. The standardization of the iodine solution using ascorbic acid was accurate and precise, with the advantages of saving time and avoiding mistakes due to solution preparation. The colorless ascorbic acid solution gives a very clear and sharp titration end point with starch. It was shown by thermogravimetric analysis that ascorbic acid can be dried at 393 K for 2 h without decomposition. This experiment allows general chemistry students to perform an iodometric titration during a single laboratory period, determining with precision the content of vitamin C in pharmaceutical formulations.

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

    OpenAIRE

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

    2007-01-01

    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...

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

    OpenAIRE

    Shishehbore, Masoud Reza; Aghamiri, Zahra

    2014-01-01

    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...

  20. Photoelectrochemical determination of ascorbic acid using methylene blue immobilized in alpha-zirconium phosphate

    OpenAIRE

    Cooper, Ja; Woodhouse, Ke; Chippindale, Am; Compton, Rg

    1999-01-01

    Photoelectrochemical analysis of ascorbic acid is reported in aqueous solution at a platinum channel electrode using the dissolved phenothiazine dyes methylene blue and methylene green. This is achieved by measuring the current produced by immediate electrooxidation of the reduced form of the dyes produced during the 1:1 photoreaction between the dyes and ascorbic acid induced by visible light. This behavior is similar to that reported previoulsy for toluidine blue, and rate constants for the...

  1. Cell proliferation of the ileum intestinal mucosa of diabetic rats treated with ascorbic acid

    OpenAIRE

    Jacqueline Nelisis Zanoni; Renata Virginia Fernandes Pereira

    2008-01-01

    The objective of this work was to evaluate the effect of the ascorbic acid supplementation on the cellular proliferation on the ileum mucosa of diabetic rats. Fifteen 90-days rats were divided in the groups: control, diabetic and diabetic supplemented with ascorbic acid (DA). Two hours prior the sacrifice, they were injected with Vincristin. Semi-seriate histological cuts stained with HE were accomplished. About 2500 crypt cells from the intestinal mucosa were counted in order to obtain the m...

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

    OpenAIRE

    Lawal, A. O.; Ologundudu, A.; Obi, F. O.; Ogungbe, I. V.; Olakanye, A. O.; Agbetuyi, A. R.; Kayode, O. F.; Medale, T.

    2006-01-01

    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 paraceta...

  3. Role of ascorbic acid against pathogenesis in plants

    Directory of Open Access Journals (Sweden)

    Taqi Ahmed Khan

    2011-09-01

    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.

  4. Quantitative Determination of Citric and Ascorbic Acid in Powdered Drink Mixes

    Science.gov (United States)

    Sigmann, Samuella B.; Wheeler, Dale E.

    2004-01-01

    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.

  5. Effect of Supplemental Ascorbic Acid on the Aerobic Capacity in Children

    Directory of Open Access Journals (Sweden)

    Gholamreza Sharifi

    2014-10-01

    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.

  6. Degradation kinetic modelling of ascorbic acid and colour intensity in pasteurised blood orange juice during storage.

    Science.gov (United States)

    Remini, Hocine; Mertz, Christian; Belbahi, Amine; Achir, Nawel; Dornier, Manuel; Madani, Khodir

    2015-04-15

    The stability of ascorbic acid and colour intensity in pasteurised blood orange juice (Citrus sinensis [L.] Osbeck) during one month of storage was investigated at 4-37 °C. The effects of ascorbic acid fortification (at 100, 200 mg L(-1)) and deaeration, temperature/time storage on the kinetic behaviour were determined. Ascorbic acid was monitored by HPLC-DAD and colour intensity by spectrophotometric measurements. Degradation kinetics were best fitted by first-order reaction models for both ascorbic acid and colour intensity. Three models (Arrhenius, Eyring and Ball) were used to assess the temperature-dependent degradation. Following the Arrhenius model, activation energies were ranged from 51 to 135 kJ mol(-1) for ascorbic acid and from 49 to 99 kJ mol(-1) for colour intensity. The effect of storage temperature and deaeration are the most influent factors on kinetics degradation, while the fortification revealed no significant effect on ascorbic acid content and colour intensity. PMID:25466074

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

    International Nuclear Information System (INIS)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-31

    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.

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

    Science.gov (United States)

    Sivaci, Aysel; Kaya, A; Duman, Sevcan

    2014-09-01

    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

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

    International Nuclear Information System (INIS)

    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)

  11. Expression of ascorbic acid oxidase in zucchini squash (Cucurbita pepo L. )

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Liangshiou; Varner, J.E. (Washington Univ., St. Louis, MO (United States))

    1991-05-01

    The expression of ascorbic acid oxidase was studied in zuchini squash (Cucurbita pepo L.), one of the most abundant natural sources of the enzyme. In the developing fruit, specific activity of ascorbic acid oxidase was highest between 4 and 6 days after anthesis. Protein and mRNA levels followed the same trend as enzyme activity. Highest growth rate of the fruit occurred before 6 days after anthesis. Within a given fruit, ascorbic acid oxidase activity was higher in young leaves, and very low in old leaves. Within a given leaf, enzyme activity was highest in the fast-growing region (approximately the lower third of the blade), and lowest in the central placental region. In leaf tissue, ascorbic acid oxidase activity was higher in young leaves, and very low in old leaves. Within a given leaf, enzyme activity was highest in the fast-growing region (approximately the lower third of the blade), and lowest in the slow-growing region (near leaf apex). High expression of ascorbic acid oxidase at a stage when rapid growth is occurring (in both fruits and leaves), and localization of the enzyme in the fruit epidermis, where cells are under greatest tension during rapid growth in girth, suggest that ascorbic acid oxidase might be involved in reorganization of the cell wall to allow for expansion. Based on the known chemistry of dehydroascorbic acid, the end product of the ascorbic acid oxidase-catalyzed reaction, the authors have proposed several hypotheses to explain how dehydroascorbic acid might cause cell wall loosening.

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

    International Nuclear Information System (INIS)

    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

  13. Biosynthesis of L-ascorbic acid and conversion of carbons 1 and 2 of L-ascorbic acid to oxalic acid occurs within individual calcium oxalate crystal idioblasts.

    Science.gov (United States)

    Kostman, T A; Tarlyn, N M; Loewus, F A; Franceschi, V R

    2001-02-01

    L-Ascorbic acid (AsA) and its metabolic precursors give rise to oxalic acid (OxA) found in calcium oxalate crystals in specialized crystal idioblast cells in plants; however, it is not known if AsA and OxA are synthesized within the crystal idioblast cell or transported in from surrounding mesophyll cells. Isolated developing crystal idioblasts from Pistia stratiotes were used to study the pathway of OxA biosynthesis and to determine if idioblasts contain the entire path and are essentially independent in OxA synthesis. Idioblasts were supplied with various (14)C-labeled compounds and examined by micro-autoradiography for incorporation of (14)C into calcium oxalate crystals. [(14)C]OxA gave heavy labeling of crystals, indicating the isolated idioblasts are functional in crystal formation. Incubation with [1-(14)C]AsA also gave heavy labeling of crystals, whereas [6-(14)C]AsA gave no labeling. Labeled precursors of AsA (L-[1-(14)C]galactose; D-[1-(14)C]mannose) also resulted in crystal labeling, as did the ascorbic acid analog, D-[1-(14)C]erythorbic acid. Intensity of labeling of isolated idioblasts followed the pattern OxA > AsA (erythorbic acid) > L-galactose > D-mannose. Our results demonstrate that P. stratiotes crystal idioblasts synthesize the OxA used for crystal formation, the OxA is derived from the number 1 and 2 carbons of AsA, and the proposed pathway of ascorbic acid synthesis via D-mannose and L-galactose is operational in individual P. stratiotes crystal idioblasts. These results are discussed with respect to fine control of calcium oxalate precipitation and the concept of crystal idioblasts as independent physiological compartments. PMID:11161021

  14. Oxidized LDL Up-Regulates the Ascorbic Acid Transporter SVCT2 in Endothelial Cells

    OpenAIRE

    May, James M.; Li, Liying; Qu, Zhi-chao

    2010-01-01

    Endothelial dysfunction is an early manifestation of atherosclerosis caused in part by oxidized LDL (oxLDL). Since vitamin C, or ascorbic acid, prevents several aspects of endothelial dysfunction, the effects of oxLDL on oxidative stress and regulation of the ascorbate transporter, SVCT2, were studied in cultured EA.hy926 endothelial cells. Cells cultured for 18 h with 0.2 mg/ml oxLDL showed increased lipid peroxidation that was prevented by a single addition of 0.25 mM ascorbate at the begin...

  15. Synthesis of L-ascorbic acid in the phloem

    Directory of Open Access Journals (Sweden)

    Haupt Sophie

    2003-11-01

    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.

  16. Effects of Ascorbic Acid, Phytic Acid and Tannic Acid on Ferritin-Iron Bioavailability as Determined Using an In Vitro Digestion/Caco-2 Cell Model

    Science.gov (United States)

    The effects of ascorbic acid, phytate and tannic acid on Fe bioavailability from Fe supplied as ferritin was compared to FeSO4 using an in vitro digestion/Caco-2 cell model. Horse spleen ferritin (HSF) was chemically reconstituted into a plant-type ferritin (P-HSF). In the presence of ascorbic acid...

  17. Effects of Ascorbic Acid, Phytic Acid and Tannic Acid on Iron Bioavailability from Reconstituted Ferritin Measured by an In Vitro Digestion/Caco-2 Cell Model

    Science.gov (United States)

    The effects of ascorbic acid, phytate and tannic acid on Fe bioavailability from Fe supplied as ferritin was compared to FeSO4 using an in vitro digestion/Caco-2 cell model. Horse spleen ferritin (HSF) was chemically reconstituted into a plant-type ferritin (P-HSF). In the presence of ascorbic acid...

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

    Directory of Open Access Journals (Sweden)

    Bogin Vladimir

    2011-03-01

    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.

  19. Effect of eradication of Helicobacter pylori on gastric juice ascorbic acid concentrations.

    OpenAIRE

    Sobala, G. M.; Schorah, C. J.; Shires, S.; Lynch, D. A.; Gallacher, B.; Dixon, M. F.; Axon, A. T.

    1993-01-01

    Ascorbic acid, the reduced form of vitamin C, may protect against gastric cancer and is secreted by the normal stomach. Secretion is impaired in Helicobacter pylori (H pylori) associated chronic gastritis. This study examined if eradication of H pylori improves gastric juice ascorbate values. Fasting gastric juice and plasma samples were collected at endoscopy from patients participating in trials of H pylori eradication for duodenal ulcer disease and intestinal metaplasia before and up to 15...

  20. 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)

  1. Determination of Dopamine in the Presence of Ascorbic Acid using Poly (Acridine red) Modified Glassy Carbon Electrode

    OpenAIRE

    Zhousheng Yang; Yanling Wang; Guiying Jin; Yuzhong Zhang

    2003-01-01

    Poly (acridine red) modified glassy carbon electrode was used for the detection of dopamine in the presence of ascorbic acid in a pH 7.4 phosphate buffer solutions (PBS) by cyclic voltammetry and differential pulse voltammetry. The major difficulty of the overlapped oxidation potential of ascorbic acid could be overcome through the distinct attractive ability of poly (acridine red) film to cationic dopamine and anionic ascorbic acid. The results showed that the dopamine anodic peak current an...

  2. 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

  3. 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

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

    Directory of Open Access Journals (Sweden)

    Mirsad Salki?

    2009-12-01

    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.

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

    Scientific Electronic Library Online (English)

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

    2008-12-01

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    Cvetkovi? Biljana R.

    2012-01-01

    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.

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

    Scientific Electronic Library Online (English)

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

    1211-12-01

    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.

  8. 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)licity in fabrication. (author)

  9. A novel approach for reliable activity determination of ascorbic acid depending myrosinases.

    Science.gov (United States)

    Kleinwächter, Maik; Selmar, Dirk

    2004-06-30

    Up to now, a wide array of methods for the determination of myrosinase activity has been described. These vary from the simple photometric estimation to highly sophisticated assays using radioactively labelled substrates. However, ascorbic acid--an effective activator of myrosinases--interferes with most of these enzyme tests. Unfortunately, in the past, such interferences were disregarded in many scientific examinations of myrosinases. Whereas such failings have less effects when the activation of myrosinases is not very distinctive, they are quite relevant in all cases where myrosinases are completely inactive in the absence of ascorbic acid. In this paper, the current methods for myrosinase determination are reviewed critically with special emphasis on putative interferences with ascorbic acid. Thereafter, an alternative and interference-free HPLC-based quantification method of the enzymatically produced glucose is presented. Due to the benzoylation of glucose, it becomes possible to quantify even those exiguous glucose concentrations, which are indispensable for correct determination of kinetic enzyme data in the presence of ascorbic acid. Using this new method, the activity of Tropaeolum majus myrosinase towards glucotropaeolin was analyzed. This enzyme shows a distinctive activation by ascorbic acid with maximal activation at a concentration of about 2 mM. PMID:15165756

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

    Scientific Electronic Library Online (English)

    Devaney R. do, Carmo; Ricardo M. da, Silva; Nelson R., Stradiotto.

    Full Text Available SciELO Portugal | Language: English Abstract in english Iron nitroprusside, Fe(II)NP was incorporated into a carbon paste electrode and the electrochemical studies were performed by cyclic voltammetry. The cyclic voltammogram of the modified electrode, Fe(II)NP showed two redox couples ( E½ox)1 = 0.24 and (E½ox)2 = 0.85 V vs. SCE attributed to Fe(II)/Fe( [...] III) and Fe(II)(CN)5NO / Fe(III)(CN)5NO, respectively. The redox couple at (E½ox)1 = 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.

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

    Directory of Open Access Journals (Sweden)

    Devaney R. do Carmo

    2004-01-01

    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.

  12. 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

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

    Science.gov (United States)

    Chang, Soo Im; Jin, Bohwan; Youn, Pilju; Park, Changbo; Park, Jung-Duck; Ryu, Doug-Young

    2007-01-15

    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 3beta-hydroxysteroid dehydrogenase (HSD) and 17beta-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. PMID:17188728

  14. INFLUENCE OF ASCORBIC ACID ON EGG QUALITY INFLUÊNCIA DO ÁCIDO ASCÓRBICO NA QUALIDADE DO OVO

    OpenAIRE

    Souza, Pedro Alves; Souza, Hirasilva Borba Alves; Oba, Alexandre; Gardini, Claudio Henrique Cruz

    2001-01-01

    The egg quality may be influenced by some nutrients added to laying hens diets and among these nutrients, the ascorbic acid is included. According to some researches, this acid, besides of improving the quality, it can increase the egg production and weight. In addition, it reduces the quantity of cracked eggs and food intake. In order to contribute with more information, this experiment was developed. Concentrations of 100; 150 and 200mg/kg of ascorbic acid were added to rations of laying he...

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

    OpenAIRE

    Kapoor And Shelja Pandita, B. B. S.

    2013-01-01

    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).

  16. A model study on rate of degradation of L-ascorbic acid during processing using home-produced juice concentrates.

    Science.gov (United States)

    Roig, M G; Rivera, Z S; Kennedy, J F

    1995-05-01

    The rate of degradation of L-ascorbic acid in solution has been investigated under varying conditions, such as temperature, level of dissolved oxygen, pH, amino acids, sugars and processing conditions. Changes in pH between pH 1.5 and 7.0 accelerate L-ascorbic acid degradation. The most important factor that determines its stability is storage temperature, on which the rate of degradation of L-ascorbic acid is directly dependent. Similarly, the deleterious effect of variables such as oxygen and pH are influenced by temperature. Therefore, low temperature storage is imperative in order to regard L-ascorbic acid delay. A definite role of amino acids in L-ascorbic acid degradation has not been identified. PMID:7621082

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

    Directory of Open Access Journals (Sweden)

    R. Suresh

    2010-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    GHASEM KARIM-NEZHAD

    2009-05-01

    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.

  19. Spectrophotometric determination of uranium using ascorbic acid as a chromogenic reagent

    International Nuclear Information System (INIS)

    A spectrophotometric method has been developed for the determination of uranium(VI) using ascorbic acid. Uranium in the hexavalent state forms a reddish-brown coloured complex with ascorbic acid. The colour intensity of the complex is maximum at pH 4.2-4.5 and is stable for 24 hr. The absorbances of uranium(VI)-ascorbic acid complex at 360 and 450 nm are used for its quantification. Uranium in the range 8-200 ?g/ml has been determined with good precision. The method allows the determination of uranium in the presence of many metal ions present as impurities. The described method is simple, accurate and applicable to uranium concentration relevant to the PUREX process and thus can be used for analytical control purposes. (author)

  20. Copper malabsorption after intestinal resection in rats. Effects of cholecalciferol and ascorbic acid.

    Science.gov (United States)

    Hartiti, S; López-Aliaga, I; Lisbona, F; Barrionuevo, M M; Alférez, M J; Gómez-Ayala, A E; Pallarés, I; Campos, M S

    1995-01-01

    Dietary modifications can partly compensate for the alterations in copper homeostasis caused by distal intestinal resection, by improving biliary function. We studied the effects of resecting 50% of the distal small intestine (DSI) on copper status in rats fed three semisynthetic diets (basal diet, and basal diet with cholecalciferol or ascorbic acid). Intestinal resection significantly decreased the digestive (apparent digestibility coefficient; ADC) and metabolic utilization (balance) of copper 1 month after surgery. However, the supplementation of the basal diet with cholecalciferol attenuated the negative impact of surgery, leading to small differences in Cu ADC and Cu balance between transected and resected rats. Ascorbic acid also enhanced copper retention. Copper status was not as markedly affected by intestinal resection as digestive utilization 1 month after the operation. The beneficial effects of cholecalciferol and ascorbic acid at the digestive and metabolic levels suggest ways to lessen the impact of intestinal resection, and to avoid possible long-term postabsorptive alterations in copper distribution. PMID:8546439

  1. 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.

  2. Effects of intestinal resection, cholecalciferol and ascorbic acid on iron metabolism in rats.

    Science.gov (United States)

    Hartiti, S; Barrionuevo, M; López-Aliaga, I; Lisbona, F; Pallarés, I; Alférez, M J; Gómez-Ayala, A E; Campos, M S

    1995-06-01

    The effect of dietary supplementation with ascorbic acid or cholecalciferol on Fe utilization was studied using the metabolic balance technique, in rats in which 50% of the distal small intestine was removed, or in which the mid small intestine was transected and reanastomosed (controls). Three different diets were used. The first (basal diet) contained (g/kg dry wt): protein (casein + 50 mg D,L-methionine/g) 120 and fat (medium-chain triacylglycerols, olive oil and sunflower oil, in equal parts) 40. The other diets were obtained by adding ascorbic acid (150 mg/kg diet) or cholecalciferol (0.4 mg/kg diet) to the basal diet. Apparent digestibility coefficient (ADC) and Fe retention were significantly lower in resected animals than in their respective control groups (transected rats). However, the addition of ascorbic acid or cholecalciferol to the basal diet increased the ADC and Fe retention in both transected and resected rats. Five weeks after surgery, resection also resulted in a reduced concentration of Fe in the sternum, but did not reduce the concentration of haemoglobin or serum Fe total Fe-binding capacity or the concentration of Fe in liver, testes, femur or muscle (longissimus dorsi). Supplementation with ascorbic acid increased serum Fe concentration, while the concentration of Fe in muscle was reduced by supplementation with both ascorbic acid and cholecalciferol. Neither supplementation had any effect on the Fe concentration in other tissues, on haemoglobin concentration or plasma total Fe-binding capacity. Thus, supplementation with ascorbic acid or with cholecalciferol increased Fe absorption and reduced the concentration of Fe in muscle. PMID:7632668

  3. 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)

  4. Genetic variation in sodium-dependent ascorbic acid transporters and risk of gastric cancer in Poland

    OpenAIRE

    Wright, Margaret E.; Andreotti, Gabriella; Lissowska, Jolanta; Yeager, Meredith; Zatonski, Witold; Chanock, Stephen J.; Chow, Wong-ho; Hou, Lifang

    2009-01-01

    Higher ascorbic acid consumption is associated with a reduced risk of gastric cancer in numerous epidemiologic studies. We investigated whether single nucleotide polymorphisms (SNPs) in SLC23A1 and SLC23A2 — genes that encode key ascorbic acid transport proteins — affect gastric cancer risk in 279 incident cases and 414 age- and gender-matched controls drawn from a population-based case-control study in Poland. Compared to subjects who were homozygous for the common G allele of the SLC23A...

  5. Water disinfection with the hydrogen peroxide-ascorbic acid-copper (II) system.

    OpenAIRE

    Ragab-depre, N. J.

    1982-01-01

    Treatment of secondary effluents with hydrogen peroxide (10 mg/liter)-ascorbic acid (10 mg/liter)-Cu2+ (0.5 mg/liter) for 60 min resulted in around 99% reduction of the initial plate count. Hydrogen peroxide could be replaced by other peroxygen compounds; ascorbic acid could be replaced by other reducing agents, of which sodium sulfite and ethanol were the most effective. Cu2+, however, could not be replaced by other metal ions without loss of bactericidal efficiency of the ternary combinatio...

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

    OpenAIRE

    Dickton Darby; Brewer Paul; Rogers Kristy; Francis Jimi; Pardini Ron

    2008-01-01

    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 ...

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

    Directory of Open Access Journals (Sweden)

    Piya Kosai

    2007-01-01

    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.

  8. 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)

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

    OpenAIRE

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

    2010-01-01

    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 1...

  10. Study on NO2 absorption by ascorbic acid and various chemicals*

    OpenAIRE

    Li, Wei; Wu, Cheng-zhi; Fang, He-liang; Shi, Yao; Lei, Le-cheng

    2005-01-01

    Study on NO2 absorption aimed at seeking a better NO2 absorption chemical at pH 4.5~7.0 for application to existing wet flue gas desulfurization (FGD). The results from the double-stirred reactor indicated that ascorbic acid has very high absorption rate at this pH range. The rate constant of ascorbic acid reaction with NO2 (0~1000×10?6 mol/mol) is about 3.54×106 mol/(L·s) at pH 5.4~6.5 at 55 °C.

  11. Reactions of H atoms and OH radicals with ascorbic acid. A pulse radiolysis Fourier transform ESR study

    International Nuclear Information System (INIS)

    Using pulse radiolysis, free radicals of ascorbic acid were generated by reactions of the primary radicals H and OH in acidic and basic aqueous solutions. The formation and the decay of several radicals of ascorbic acid were detected by time resolved Fourier transform electron spin resonance within a time interval of 100 ns to 1 ms. The rate constant of addition of H atoms to ascorbic acid (1.3 x 108 dm3 x mol-1 x s-1) was directly determined by the change of line width of the low field line of the H atom in the presence of ascorbic acid. The addition of OH radicals to ascorbic acid results in different radical structures, detected by highly resolved Fourier transform ESR spectra. (author)

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

    Directory of Open Access Journals (Sweden)

    Venkata Sai

    2009-01-01

    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.

  13. Comparison of oxalate formation from ascorbic and glyoxyl acids in detached glandular heads of tobacco trichomes

    Energy Technology Data Exchange (ETDEWEB)

    Vogeli-Lange, R.; Wagner, G.J.

    1987-08-01

    Ca-oxalate crystal containing cells from detached glandular heads of trichomes from Nicotiana tabacum, TI 1068, are capable of converting (1-/sup 14/C) ascorbic acid (AA) and (1-/sup 14/C) glyoxylic acid (GA) to oxalate. AA was found to be a better precursor for oxalate formation than GA. In detached glandular heads, 3.6x more label was converted to oxalate from AA than from GA, in the epidermis the factor was 3x while that with petiole tissue was 7x. Oxalate formation from AA, in detached glandular heads, was only partially inhibited in the dark and in the presence of metabolic inhibitors, suggesting that a nonenzymatic component might be involved. Oxalate formation from GA increased in the presence of metabolic inhibitors. During treatment of detached glandular heads with 2 mM Ca-acetate for 2 days, oxalate formation from AA was stimulated 3 fold, while the presence of 2mM Ca-acetate had no effect on the oxalate formation from GA. These results suggest that Ca/sup 2 +/ stimulates the formation of Ca-oxalate crystals in glandular head cells, and that AA can serve as a precursor for oxalate production.

  14. Comparison of oxalate formation from ascorbic and glyoxyl acids in detached glandular heads of tobacco trichomes

    International Nuclear Information System (INIS)

    Ca-oxalate crystal containing cells from detached glandular heads of trichomes from Nicotiana tabacum, TI 1068, are capable of converting [1-14C] ascorbic acid (AA) and [1-14C] glyoxylic acid (GA) to oxalate. AA was found to be a better precursor for oxalate formation than GA. In detached glandular heads, 3.6x more label was converted to oxalate from AA than from GA, in the epidermis the factor was 3x while that with petiole tissue was 7x. Oxalate formation from AA, in detached glandular heads, was only partially inhibited in the dark and in the presence of metabolic inhibitors, suggesting that a nonenzymatic component might be involved. Oxalate formation from GA increased in the presence of metabolic inhibitors. During treatment of detached glandular heads with 2 mM Ca-acetate for 2 days, oxalate formation from AA was stimulated 3 fold, while the presence of 2mM Ca-acetate had no effect on the oxalate formation from GA. These results suggest that Ca2+ stimulates the formation of Ca-oxalate crystals in glandular head cells, and that AA can serve as a precursor for oxalate production

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

    Science.gov (United States)

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

    1975-01-01

    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

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

    Directory of Open Access Journals (Sweden)

    Badreh F

    2012-02-01

    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.

  17. The human sodium-dependent ascorbic acid transporters SLC23A1 and SLC23A2 do not mediate ascorbic acid release in the proximal renal epithelial cell.

    Science.gov (United States)

    Eck, Peter; Kwon, Oran; Chen, Shenglin; Mian, Omar; Levine, Mark

    2013-11-01

    Sodium-dependent ascorbic acid membrane transporters SLC23A1 and SLC23A2 mediate ascorbic acid (vitamin C) transport into cells. However, it is unknown how ascorbic acid undergoes cellular release, or efflux. We hypothesized that SLC23A1 and SLC23A2 could serve a dual role, mediating ascorbic acid cellular efflux as well as uptake. Renal reabsorption is required for maintaining systemic vitamin C concentrations. Because efflux from nephron cells is necessary for reabsorption, we studied whether SLC23A1 and SLC23A2 mediate efflux of ascorbic acid in the human renal nephron. We found high gene expression of SLC23A1 but no expression of SLC23A2 in the proximal convoluted and straight tubules of humans. These data rule out SLC23A2 as the ascorbic acid release protein in the renal proximal tubular epithelia cell. We utilized a novel dual transporter-based Xenopus laevis oocyte system to investigate the function of the SLC23A1 protein, and found that no ascorbate release was mediated by SLC23A1. These findings were confirmed in mammalian cells overexpressing SLC23A1. Taken together, the data for SLC23A1 show that it too does not have a role in cellular release of ascorbic acid across the basolateral membrane of the proximal tubular epithelial cell, and that SLC23A1 alone is responsible for ascorbic acid uptake across the apical membrane. These findings reiterate the physiological importance of proper functioning of SLC23A1 in maintaining vitamin C levels for health and disease prevention. The ascorbate efflux mechanism in the proximal tubule of the kidney remains to be characterized. PMID:24400138

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

    Science.gov (United States)

    Salimi, Abdollah; Mamkhezri, Hussein; Hallaj, Rahman

    2006-11-15

    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

  19. NITROGEN DIOXIDE EXPOSURE AND LUNG ANTIOXIDANTS IN ASCORBIC ACID-DEFICIENT GUINEA PIGS

    Science.gov (United States)

    The authors have previously found that ascorbic acid (AA) deficiency in guinea pigs enhances the pulmonary toxicity of nitrogen dioxide (NO2). The present study showed that exposure to NO2 (4.8 ppm, 3 hr) significantly increased lung lavage fluid protein (a sensitive indicator of...

  20. Ascorbic acid, cognitive function, and Alzheimer’s disease: a current review and future direction

    OpenAIRE

    Bowman, Gene L.

    2012-01-01

    This narrative review appraises the human and animal studies implicating ascorbic acid (AA) in normal cognitive function and Alzheimer’s disease. A research framework for how nutrition affects brain aging is proposed with emphasis on AA intake, status, metabolism, and transport into brain tissue. A final synopsis highlights areas for future research regarding AA nourishment and healthy brain aging.

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

    OpenAIRE

    Kapoor And Raksha Mishra, B. B. S.

    2013-01-01

    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).

  2. PLASMID DNA DAMAGE CAUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    Science.gov (United States)

    Plasmid DNA damage caused by methylated arsenicals, ascorbic acid and human liver ferritin. Arsenic causes cancer in human skin, urinary bladder, lung, liver and kidney and is a significant world-wide public health problem. Although the metabolism of inorganic arsenic is ...

  3. Ascorbic acid as a new reductant in the thiocyanate method for the spectrophotometric determination of rhenium

    International Nuclear Information System (INIS)

    A spectrophotometric determination of rhenium is based on its reduction with ascorbic acid in the presence of thiocyanate. The orange-yellow complex is extracted into isoamyl alcohol and the absorbance measured at 430 nm. Various foreign ions do not interfere. Molar absorptivity and Sandell's sensitivity are 31162.79 l/mol/cm and 0.0059 ?g/cm2, respectively. (orig.)

  4. Synergism in the extraction of ascorbic and nicotinic acids by binary solvent mixtures

    Science.gov (United States)

    Mokshina, N. Ya.; Erina, O. V.; Pakhomova, O. A.; Savushkin, R. V.

    2007-12-01

    The distribution coefficients of ascorbic and nicotinic acids in systems aqueous salt solution-binary mixture of hydrophilic solvents were determined. Butanol, ethyl acetate, and butyl acetate were used as hydrophilic solvents and sodium chloride and sulfate as salting out agents. The synergistic effect was interpreted and the synergistic coefficients, complex formation constants, and solvation numbers calculated.

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

    Directory of Open Access Journals (Sweden)

    Jokanovi? Marija R.

    2009-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Samuel Tilahun

    2013-10-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Samuel Tilahun

    2013-08-01

    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.

  8. 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.)

  9. Antioxidative activity of citric and ascorbic acids and their preventive effect on lipid oxidation in frozen persian sturgeon fillets

    Scientific Electronic Library Online (English)

    H., Rostamzad; B., Shabanpour; M., Kashaninejad; A., Shabani.

    2011-04-01

    Full Text Available SciELO Argentina | Language: English Abstract in english Persian sturgeon (Acipenser persicus) fillets were soaked in Citric acid, Ascorbic acid and combination of Citric and Ascorbic acid solutions and then were stored at frozen conditions (-18 °C) up to 6 months. During storage, some general chemical analysis such as free fatty acids, primary and second [...] ary oxidation products and sensory analysis were measured in order to study rancidity development. Results showed that antioxidant treatments had lower (P

  10. 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)

  11. Ascorbic Acid Rejection Characteristics of Modified Platinum Electrodes: A Shelf Life Investigation

    Directory of Open Access Journals (Sweden)

    Andrea M. Wynne

    2015-04-01

    Full Text Available Ascorbic acid (AA is the principle interferent present in brain extracellular fluid that can inhibit the ability of electrochemical sensors to selectively detect a particular analyte of interest. Considerable efforts have been made in recent times to develop highly selective membrane coatings to counteract the drawbacks associated with AA interference during in vivo monitoring. The primary objective of the work described within was to investigate the long term effect of storing such selective membranes, i.e., Nafion® and Poly-o-phenylenediamine (PPD under different conditions and how exposing them to repeated calibration protocols compromises the membranes ability to reject AA. Four different modified platinum (Pt electrodes, Pt-PPD, Pt-Nafion® (5/2, Pt-Nafion® (1/2-PPD, and Pt-Nafion® (2/1-PPD, stored at 4 °C demonstrated deterioration of the polymers integrity when exposed to repeated calibrations. On the contrary, exposing the same four electrode types to single calibrations confirmed excellent retention of AA rejection characteristics. Pt-PPD electrodes were then exposed to varying storage conditions and calibrated against AA on day 1, day 56 and day 168. Storing the Pt-PPD electrodes at 4 °C/N2 saturated glass container demonstrated retention of AA rejection characteristics after day 168. These results have clearly elucidated the optimum storage conditions for Pt-Nafion® and Pt-PPD modified electrodes.

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

    International Nuclear Information System (INIS)

    The oxidation of norepinephrine (NE) on a preactivated glassy carbon electrode leads to the formation of a deposited layer of about 4.2 x 10-10 mol cm-2 at the surface of the electrode. The electron transfer rate constant, k s, and charge transfer coefficient, ?, for electron transfer between the electrode and immobilized NE film were calculated as 44 s-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 h was found to be 8.42 x 103 M-1 s-1. Amperometric determination of AA in stirred solution exhibits a linear range of 2.0-1300.0 ?M (correlation coefficient 0.9999) and a detection limit of 0.076 ?M. The precision of amperometry was found to be 1.9% for replicate determination of a 49.0 ?M solution of AA (n = 6). In differential pulse voltammetric measurements, the NE-modified glassic 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

  13. Kolaviron and L-Ascorbic Acid Attenuate Chlorambucil-Induced Testicular Oxidative Stress in Rats

    OpenAIRE

    Ebenezer Tunde Olayinka; Ayokanmi Ore

    2014-01-01

    Chlorambucil (4-[4-[bis(2-chloroethyl)amino]phenyl]butanoic acid) is an alkylating agent, indicated in chronic lymphocytic leukaemia. Kolaviron (KV), a biflavonoid complex from Garcinia kola, and L-ascorbic acid (AA) are known to protect against oxidative damage in vivo. This study evaluates the protective capacity of KV and AA on chlorambucil-induced oxidative stress in the testes of rat. Twenty male Wistar rats (180–200?g) were randomized into four groups: I: control, II: chlorambucil (...

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

    Directory of Open Access Journals (Sweden)

    Mervat Sh. Sadak

    2014-03-01

    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.

  15. The study of molecular interactions of ascorbic acid and sodium ascorbate with water at temperatures (278.15, 288.15 and 298.15) K

    International Nuclear Information System (INIS)

    Highlights: • Density, speed of sound, viscosity and refractive index of important vitamins are reported. • Molecular interactions of ascorbic acid and sodium ascorbate in water have been studied. • V?0 and B-coefficient of solutes studied show the presence of strong solute–solvent interaction. • These interactions strengthened at higher temperatures. • Ascorbic acid and sodium ascorbate act as a water structure destroyer (Chaotropes). -- Abstract: The article reports experimental values of density (?), speed of sound (u), viscosity (?) and refractive index (nD) for the binary systems, (L-ascorbic acid + water) and (sodium ascorbate + water) over the concentration range (0.01 to 0.75) mol · kg?1 at temperatures (T = 278.15, 288.15 and 298.15) K. From these experimental results, apparent molar volume (V?) of solute, isentropic compressibility of solution (?S), apparent molar isentropic compressibility (??) of solute and relative viscosity of solution (?r) have been calculated. The limiting apparent molar volume (V?0) of solute, limiting apparent molar isentropic compressibility (??0), limiting apparent molar expansivity (E?0) of solute, coefficient of thermal expansion (??) and hydration number (nH) of water soluble vitamins have been obtained. The experimental values of relative viscosity were used to calculate Falkenhagen coefficient A and Jones–Dole coefficient B. The transition state theory has been used to calculate the Gibbs free energy of activation of viscous flow per mole of solvent (??10numbersign) and per mole of solute (??20numbersign). The related activation parameters like ?S20numbersign and ?H20numbersign have also been calculated. From the results obtained, a discussion was carried out in terms of interactions and structure factor (in the framework of “structure-making” and “structure-breaking” solutes) in these binary mixtures

  16. Electrocatalytic Activity of Carbonized Nanostructured Polyanilines for Oxidation Reactions: Sensing of Nitrite Ions and Ascorbic Acid

    International Nuclear Information System (INIS)

    Highlights: • Carbonized PANIs prepared from various nanostructured PANI precursors • Electroanalytical performances of carbonized PANIs evaluated using voltammetry • Study of carbonized PANIs physico-chemical properties related to electroactivity • The lowest over-potential for NO2? oxidation at c-PANI (+0.87 V vs. SCE) • The lowest over-potential for ascorbic acid oxidation at both c-PANI and c-PANI-SSA - Abstract: A comparative study of the electrocatalytic activity of nitrogen-containing carbon nanomaterials, prepared by the carbonization of nanostructured polyaniline (PANI) salts, for the electrooxidation reactions is presented. Nanostructured PANI salts were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous solution in the presence of 5-sulfosalicylic acid (PANI-SSA), 3,5-dinitrosalicylic acid (PANI-DNSA) as well as without added acid (PANI), and subsequently carbonized to c-PANI-SSA, c-PANI-DNSA and c-PANI, respectively. Glassy carbon tip was modified with nanostructured c-PANIs and used for the investigation of sensing of nitrite and ascorbic acid in aqueous solutions as model analytes by linear sweep voltammetry. All three types of the investigated c-PANIs gave excellent response to the nitrite ions and ascorbic acid electrooxidation. The lowest peak potential for nitrite ion oxidation exhibited c-PANI (+0.87 V vs. SCE), and for ascorbic acid oxidation both c-PANI and c-PANI-SSA (ca. + 0.13 V vs. SCE). Electrochemical data were correlated with structural and textural data obtained by Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, elemental and nitrogen sorption analysis

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

    Directory of Open Access Journals (Sweden)

    Farouk S.

    2011-09-01

    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.

  18. The spectrophotometric method for the determination of vanadium and ascorbic acid by means of eriochrome cyanine R and lauryldimethylbenzylammonium bromide

    International Nuclear Information System (INIS)

    The spectrophotometric method determination of the microgram amounts of vanadium and ascorbic acid with Eriochrome Cyanine R (ECR) and cationic surfactant: lauryldimethylbenzylammonium bromide (ST) is described. The complex between vanadium(IV), ECR and ST is formed in the pH 5.0 ± 0.2. The molar absorptivity is 8.4 x 104. The influence of other ions has been studied. The reaction vanadium(IV) with ECR and ST was applied to determination of ascorbic acid. The molar absorptivity is 1.37 x 105. The method was used to determination of ascorbic acid in Rutinoscorbin preparation. (author). 12 refs, 2 tabs, 1 fig

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

    OpenAIRE

    Mohamed, H. E.

    2006-01-01

    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 va...

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

    International Nuclear Information System (INIS)

    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 H2SO4. 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 10-6 cm2 s-1

  1. 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)

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

    2014-10-01

    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.

  2. Nonenzymatic amperometric sensor for ascorbic acid based on hollow gold/ruthenium nanoshells

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Ara; Kang, Minkyung; Cha, Areum; Jang, Hye Su [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Shim, Jun Ho [Department of Chemistry, Daegu University, Gyeongsan 712-714 (Korea, Republic of); Lee, Nam-Suk [National Center for Nanomaterials Technology (NCNT), Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Kim, Myung Hwa [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Lee, Youngmi, E-mail: youngmilee@ewha.ac.kr [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Lee, Chongmok, E-mail: cmlee@ewha.ac.kr [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of)

    2014-03-01

    Highlights: • We synthesized hollow gold/ruthenium (hAu–Ru) nanoshells for ascorbic acid sensing. • The hAu–Ru nanoshells showed sensitivity of 426 ?A mM{sup ?1} cm{sup ?2} for ascorbic acid. • Good selectivity against glucose, uric acid, dopamine, 4-acetamidophenol, and NADH. • The linear dynamic range appeared from zero to 2.0 mM (R = 0.9995). • Response time (1.6 s) and low detection limit (2.2 ?M) were obtained at pH 7.40. - Abstract: We report a new nonenzymatic amperometric detection of ascorbic acid (AA) using a glassy carbon (GC) disk electrode modified with hollow gold/ruthenium (hAu–Ru) nanoshells, which exhibited decent sensing characteristics. The hAu–Ru nanoshells were prepared by the incorporation of Ru on hollow gold (hAu) nanoshells from Co nanoparticle templates, which enabled AA selectivity against glucose without aid of enzyme or membrane. The structure and electrocatalytic activities of the hAu–Ru catalysts were characterized by spectroscopic and electrochemical techniques. The hAu–Ru loaded on GC electrode (hAu–Ru/GC) showed sensitivity of 426 ?A mM{sup ?1} cm{sup ?2} (normalized to the GC disk area) for the linear dynamic range of <5 ?M to 2 mM AA at physiological pH. The response time and detection limit were 1.6 s and 2.2 ?M, respectively. Furthermore, the hAu–Ru/GC electrode displayed remarkable selectivity for ascorbic acid over all potential biological interferents, including glucose, uric acid (UA), dopamine (DA), 4-acetamidophenol (AP), and nicotinamide adenine dinucleotide (NADH), which could be especially good for biological sensing.

  3. Nonenzymatic amperometric sensor for ascorbic acid based on hollow gold/ruthenium nanoshells

    International Nuclear Information System (INIS)

    Highlights: • We synthesized hollow gold/ruthenium (hAu–Ru) nanoshells for ascorbic acid sensing. • The hAu–Ru nanoshells showed sensitivity of 426 ?A mM?1 cm?2 for ascorbic acid. • Good selectivity against glucose, uric acid, dopamine, 4-acetamidophenol, and NADH. • The linear dynamic range appeared from zero to 2.0 mM (R = 0.9995). • Response time (1.6 s) and low detection limit (2.2 ?M) were obtained at pH 7.40. - Abstract: We report a new nonenzymatic amperometric detection of ascorbic acid (AA) using a glassy carbon (GC) disk electrode modified with hollow gold/ruthenium (hAu–Ru) nanoshells, which exhibited decent sensing characteristics. The hAu–Ru nanoshells were prepared by the incorporation of Ru on hollow gold (hAu) nanoshells from Co nanoparticle templates, which enabled AA selectivity against glucose without aid of enzyme or membrane. The structure and electrocatalytic activities of the hAu–Ru catalysts were characterized by spectroscopic and electrochemical techniques. The hAu–Ru loaded on GC electrode (hAu–Ru/GC) showed sensitivity of 426 ?A mM?1 cm?2 (normalized to the GC disk area) for the linear dynamic range of <5 ?M to 2 mM AA at physiological pH. The response time and detection limit were 1.6 s and 2.2 ?M, respectively. Furthermore, the hAu–Ru/GC electrode displayed remarkable selectivity for ascorbic acid over all potential biological interferents, including glucose, uric acid (UA), dopamine (DA), 4-acetamidophenol (AP), and nicotinamide adenine dinucleotide (NADH), which could be especially good for biological sensing

  4. 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)

  5. 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

  6. Mutagenicity of Acridine and Ascorbic Acid in Rhizobia of Legume Trees

    Directory of Open Access Journals (Sweden)

    M.A. Nassef

    2002-01-01

    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.

  7. Quantificação dos isômeros ácido L-ascórbico e ácido D-iso-ascórbico em geleias de frutas por cromatografia líquida de alta eficiência Quantification of L-ascorbic acid and D-iso-ascorbic acid in jellies fruit by high performance liquid chromatography

    OpenAIRE

    Raquel Grando de Oliveira; Helena Teixeira Godoy; Marcelo Alexandre Prado

    2012-01-01

    Ascorbic acid has important nutritional characteristics such as high antioxidant potential, preventing diverse damage and diseases in the tissues and the process of aging. Different isomeric forms of the ascorbic acid can be found in nature and each one have different potential antioxidant and different activity pro-vitamin C. This work examined a method to detect and quantify the isomers L-ascorbic acid (LAA) and D-iso-ascorbic acid (DIAA) in jelly fruit. The method showed acceptable selecti...

  8. The oxidative degradation of barley ?-glucan in the presence of ascorbic acid or hydrogen peroxide.

    Science.gov (United States)

    Mäkelä, Noora; Sontag-Strohm, Tuula; Maina, Ndegwa Henry

    2015-06-01

    Cereal ?-glucans are polysaccharides with health benefits that have been linked to their ability to increase luminal viscosity. However, the functional properties of cereal ?-glucans may be diminished by the susceptibility of this polysaccharide to oxidative degradation. In this study, barley ?-glucan was oxidised with hydrogen peroxide or ascorbic acid and the oxidative degradation of ?-glucan was investigated using both asymmetrical flow field-flow fractionation (AsFlFFF) with aqueous solvent and high performance size exclusion chromatography (HPSEC) with LiBr in DMSO as the solvent. Oxidation was shown to cause degradation of ?-glucan, the reaction being faster when oxidised with hydrogen peroxide compared with ascorbic acid. Both HPSEC and AsFlFFF showed comparable results as long as aggregates (only observed in AsFlFFF) were not included in the integration. The compact aggregates observed in oxidised samples suggest oxidation driven interactions between ?-glucan molecules. PMID:25843872

  9. Attapulgite with poly(methylene blue) composite film-Electrocatalytic determination of ascorbic acid

    Science.gov (United States)

    Chen, Huihui; Zhang, Zhe; Cai, Dongqing; Zhang, Shengyi; Zhang, Bailin; Tang, Jilin; Wu, Zhengyan

    2012-03-01

    A conductive composite film consisted of natural nanostructure attapulgite (AT) with poly(methylene blue) (PMB) was constructed on glassy carbon (GC) electrode. The electrode exhibited an effective electrocatalytic activity towards the oxidation of ascorbic acid (AA) and well-defined oxidation peaks were observed in 0.1 M phosphate buffer solutions (PBS, pH 7.0) via cyclic voltammetry. Linear calibration plot was obtained over the range of 1.0 × 10-5 to 5.0 × 10-2 M for ascorbic acid with the detection limit value of 1.0 × 10-6 M. The main interfering factor in biological samples was experimentally excluded. In addition, UV-Vis spectra were applied to reveal the formation of the nanocomposite film of PMB-AT.

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

    Science.gov (United States)

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

    2011-08-01

    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

  11. The effect of ascorbic acid on collagen of lungs and kidneys of irradiated rats

    International Nuclear Information System (INIS)

    The effect of ascorbic acid, on the radiation induced changes in collagen of lung and kidney tissues, was evaluated in rats after whole body fractionated gamma irradiation. Animals received a dose of 7.5 Gy given in 3 fractions of 2.5 Gy every 3 days. Collagen content determined by hydroxyproline assay was carried out 1,2,3, and 4 weeks after irradiation. Progressive increase in collagen content of lungs starting from 2 nd week up to 4 th week, and at 3 weeks for kidney, was observed. Data obtained showed that intraperitoneal administration of ascorbic acid 10 mg/100 grams body weight 10 minutes before irradiation to each fraction appears capable of reducing the radiation induced collagen in the lung but not in the kidney. 2 tabs

  12. Influence of rutin and ascorbic acid in colour, plum anthocyanins and antioxidant capacity stability in model juices.

    Science.gov (United States)

    Hernández-Herrero, J A; Frutos, M J

    2015-04-15

    Model juices at pH 3.7 were prepared with different combinations of ascorbic acid, rutin (quercetin 3-rutinoside) and concentrated anthocyanin extract of plums (cv. Black Gold). The anthocyanins in the concentrated extract were cyanidin 3-glucoside and cyanidin 3-rutinoside, in a proportion of 76% and 24% respectively. The model juices were stored during 17 weeks in darkness at 20 °C. The colour stability was improved by the presence of rutin and strongly damaged by the ascorbic acid. The fortification of anthocyanin model juices with ascorbic acid originated the degradation of most of anthocyanins. However, anthocyanins improved ascorbic acid stability during storage. The copigmentation of anthocyanin and rutin showed a beneficial effect on colour stability from the 5 weeks of storage. In model juices prepared exclusively with purified plum extract a high correlation (R(2)=0.881) between anthocyanins and antioxidant capacity was found. PMID:25466051

  13. Multicommutated stepwise injection determination of ascorbic acid in medicinal plants and food samples by capillary zone electrophoresis ultraviolet detection.

    Science.gov (United States)

    Falkova, Marina T; Bulatov, Andrey V; Pushina, Maria O; Ekimov, Aleksey A; Alekseeva, Galina M; Moskvin, Leonid N

    2015-02-01

    An automation of the extraction of analytes from solid samples into the aqueous phase based on multicommutated stepwise injection analysis concept has been suggested. The feasibility of the approach has been demonstrated by determination of ascorbic acid as model analyte. The method includes automated extraction of ascorbic acid from solid sample into borate buffer solution pH 8 in mixing chamber during vigorous mixing by nitrogen stream, and subsequent detection by capillary zone electrophoresis at 254 nm. The method has a linear range of 0.1-5.0 mg g(-1) for ascorbic acid with the LOD of 0.03 mg g(-1). The sample throughput was 7 h(-1). This method was applied for determination of ascorbic acid in various medicinal plants and food samples. PMID:25435231

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

    Directory of Open Access Journals (Sweden)

    Priyanka Sharma

    2011-01-01

    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.

  15. 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)

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

    OpenAIRE

    Mirshekar, R.; Dastar, B.; Shabanpour, B.

    2009-01-01

    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 ...

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

    Directory of Open Access Journals (Sweden)

    B.B.S. Kapoor* and Raksha Mishra

    2013-06-01

    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.

  18. An Attempt at Alleviating Heat Stress Infertility in Male Broiler Breeder Chickens with Dietary Ascorbic Acid

    OpenAIRE

    Mcdaniel, C. D.; Hood, J. E.; Parker, H. M.

    2004-01-01

    Previous research regarding the effect of heat stress on broiler breeders is very limited. The objective of the present study was to determine the amount of ascorbic acid in the broiler breeders` diet that will improve reproductive performance of males that are exposed to continuous heat stress. One hundred forty-four Ross males (18 weeks old) were divided equally among six temperature controlled rooms. Three rooms were used for heat treatment and three rooms served as controls (21°C). The t...

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

    OpenAIRE

    Bogin Vladimir; Ancans Janis; Dasanu Constantin A; Alexandrescu Doru T; Miranda-Massari Jorge R; Gonzalez Michael J; Jackson James A; Mikirova Nina A; Hunninghake Ron; Luna Brandon; Braciak Todd; Minev Boris; Ichim Thomas E; Brian, Stevens R.; Markosian Boris

    2011-01-01

    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 patien...

  20. Ascorbic Acid Content in Extractive Aqueous Solutions of Rosa canina L. Fruits

    OpenAIRE

    Veturia-Ileana Nueleanu,; Maria Mihoc; Cernea Mihai

    2008-01-01

    The main goal of the hereby study is two folded: first, to mark out the most adequate methods of preparing the watery solution extracts (infusions, decoctions) in order to obtain a high content of ascorbic acid, and second, to identify the most suitable method for determining this vitamin in aqueous solution extracts made out of medicinal herbs. In this experiment six groups were assembled containing 20 fruit samples each. The samples were analyzed one week, one and a half month and three mon...

  1. 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)

  2. Synthesis of Au/Graphene Oxide Composites for Selective and Sensitive Electrochemical Detection of Ascorbic Acid

    OpenAIRE

    Song, Jian; Xu, Lin; Xing, Ruiqing; Li, Qingling; Zhou, Chunyang; Liu, Dali; Song, Hongwei

    2014-01-01

    In this work, we present a novel ascorbic acid (AA) sensor applied to the detection of AA in human sera and pharmaceuticals. A series of Au nanoparticles (NPs) and graphene oxide sheets (Au NP/GO) composites were successfully synthesized by reduction of gold (III) using sodium citrate. Then the Au NP/GO composites were used to construct nonenzymatic electrodes in practical AA measurement. The electrode that has the best performance presents attractive analytical features, such as a low workin...

  3. The use of L-ascorbic acid in speciation of arsenic compounds in drinking water

    OpenAIRE

    Marjanovi? Nikola J.; Jovani? Saša I.; Stani? Aleksandar R.; Suturovi? Zvonimir J.

    2009-01-01

    Arsenic speciation, besides total arsenic content determination, is very important in analysis of water, foodstuffs, and environmental samples, because of varying degrees of toxicity of different species. For such purpose hydride generation atomic absorption spectrometry can be used based on the generation of certain types of hydride, depending on the pH value and pretreatment in different reaction media. In this study, we have investigated the effect of L-ascorbic acid as the reaction medium...

  4. Ascorbic Acid in Human Seminal Plasma: Determination and Its Relationship to Sperm Quality

    OpenAIRE

    Colagar, Abasalt H.; Marzony, Eisa T.

    2009-01-01

    The objective of the present study was to assess the ascorbic acid (AA) levels in seminal plasma of the fertile and infertile men and to investigate its relationship with sperm count, motility and normal morphology. Semen samples were provided by fertile [smoker (n = 25), nonsmoker (n = 21)] and infertile men [smoker (n = 23), nonsmoker (n = 32)]. A simplified method of reverse phase high performance liquid chromatography (RP-HPLC) procedure using UV detection was applied for the dete...

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

    OpenAIRE

    Liviu Fartaies; Marcel Avramiuc

    2009-01-01

    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...

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

    OpenAIRE

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

    2014-01-01

    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 n...

  7. Ascorbic Acid Prevents Increased Endothelial Permeability Caused by Oxidized Low Density Lipoprotein

    OpenAIRE

    May, James M.; Qu, Zhi-chao

    2010-01-01

    Mildly oxidized low density lipoprotein (mLDL) acutely increases the permeability of the vascular endothelium to molecules that would not otherwise cross the barrier. We have shown that ascorbic acid tightens the permeability barrier in endothelial barrier in cells, so in this work we tested whether it might prevent the increase in endothelial permeability due to mLDL. Treatment of EA.hy926 endothelial cells with mLDL decreased intracellular GSH and activated the cells to further oxidize the ...

  8. Nitric Oxide Mediates Tightening of the Endothelial Barrier by Ascorbic Acid

    OpenAIRE

    May, James M.; Qu, Zhi-chao

    2010-01-01

    Vitamin C, or ascorbic acid, decreases paracellular endothelial permeability in a process that requires rearrangement of the actin cytoskeleton. To define the proximal mechanism of this effect, we tested whether it might involve enhanced generation and/or sparing of nitric oxide (NO) by the vitamin. EA.hy926 endothelial cells cultured on semi-porous filter supports showed decreased endothelial barrier permeability to radiolabeled inulin in response to exogenous NO provided by the NO donor spe...

  9. 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)

    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

    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.

  10. Computational study of the mechanism of the oxidation of ascorbic acid by iodine in the gas phase

    OpenAIRE

    Shallangwa, Gideon A.; Adamu Uzairu; Ajibola, Victor O.; Hamza Abba

    2014-01-01

    The reaction mechanisms of the oxidation of ascorbic acid by iodine have been examined using semi empirical pm3 method. The oxidation proceeded via two independent routes that can be separately monitored. One route involved a one step reaction mechanism while the other was a two steps reaction mechanism. The rsults were explained by analyses based on computational energetics of the optimised reactants, intermediates. Transition states and products of the reaction of iodine with ascorbic acid....

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

    OpenAIRE

    Ye, Nenghui; Zhang, Jianhua

    2012-01-01

    The antagonism between abscisic acid (ABA) and gibberellin (GA) plays a key role in controlling seed germination,1,2 but the mechanism of antagonism during this process is not known. In the associated study,3 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...

  12. Influence of ascorbic acid against radiation induced cytogenetic damage in mouse bone marrow

    International Nuclear Information System (INIS)

    Vitamins have generated a great deal of interest in recent years for a wide range of protective effects in biological systems. The present study is an attempt to determine the prophylactic role of ascorbic acid (Vitamin C) against radiation induced clastogenic changes in mouse bone marrow after exposure to a sublethal dose of gamma radiation. For this purpose, Swiss albino mice were irradiated to 1.60 Gy gamma radiation in the presence (experimental) and absence (control) of ascorbic acid. These animals were sacrificed between 6 h and 20 d post-irradiation, and cytogenetic alterations were noted in the form of chromosomal aberrations and micronuclei. Frequency of aberrant cells increased from 6 h by reaching to the highest at 12 h, but gradually declined thereafter, without returning to normal throughout experimentation in both the groups. The counts of such cells were significantly lower in experimental animals. When individual types of aberrations were studied, the experimental values were found to be significantly lower than the corresponding controls. The pattern of micronuclei appearance in ascorbic acid treated animals was alike control, but the counts were significantly lesser throughout the period of study. (author)

  13. 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)

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

    Directory of Open Access Journals (Sweden)

    H. Razmi and M. Harasi

    2008-01-01

    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.

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

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    Liviu Fartaies

    2009-06-01

    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

  16. IMPROVEMENT OF SALT TOLERANCE IN DURUM WHEAT BY ASCORBIC ACID APPLICATION

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    Fercha Azzedine

    2011-03-01

    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.

  17. 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

  18. 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)

  19. Cell proliferation of the ileum intestinal mucosa of diabetic rats treated with ascorbic acid

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    Jacqueline Nelisis Zanoni

    2008-08-01

    Full Text Available The objective of this work was to evaluate the effect of the ascorbic acid supplementation on the cellular proliferation on the ileum mucosa of diabetic rats. Fifteen 90-days rats were divided in the groups: control, diabetic and diabetic supplemented with ascorbic acid (DA. Two hours prior the sacrifice, they were injected with Vincristin. Semi-seriate histological cuts stained with HE were accomplished. About 2500 crypt cells from the intestinal mucosa were counted in order to obtain the metaphasic indexes. The height and depth of 30 villi and 30 crypts were measured for each animal, respectively. The metaphasic indexes showed no significant changes when we compared the three groups: 20.2 ± 0.7 (control, 18 ± 1.9 (diabetic and 17 ± 1.4 (DA (p > 0.05. The values obtained from the crypts measurement were 221.2 ± 8.5 (control, 225.3 ± 9.5 (diabetic and 222 ± 34 (DA. The villi of the control, diabetic and DA animals presented the following results: 301.7 ± 25.33, 304.8 ± 25.63 and 322.1 ± 45.77 respectively. The morphometric data were not different statistically (p > 0.05. Summing up, the present work showed that there was no alteration in the cellular proliferation of the ileum of diabetic-induced rats supplemented with ascorbic acid.

  20. Cell proliferation of the ileum intestinal mucosa of diabetic rats treated with ascorbic acid

    Scientific Electronic Library Online (English)

    Jacqueline, Nelisis Zanoni; Renata Virginia, Fernandes Pereira.

    2008-08-01

    Full Text Available SciELO Argentina | Language: English Abstract in english The objective of this work was to evaluate the effect of the ascorbic acid supplementation on the cellular proliferation on the ileum mucosa of diabetic rats. Fifteen 90-days rats were divided in the groups: control, diabetic and diabetic supplemented with ascorbic acid (DA). Two hours prior the sac [...] rifice, they were injected with Vincristin. Semi-seriate histological cuts stained with HE were accomplished. About 2500 crypt cells from the intestinal mucosa were counted in order to obtain the metaphasic indexes. The height and depth of 30 villi and 30 crypts were measured for each animal, respectively. The metaphasic indexes showed no significant changes when we compared the three groups: 20.2 ± 0.7 (control), 18 ± 1.9 (diabetic) and 17 ± 1.4 (DA) (p > 0.05). The values obtained from the crypts measurement were 221.2 ± 8.5 (control), 225.3 ± 9.5 (diabetic) and 222 ± 34 (DA). The villi of the control, diabetic and DA animals presented the following results: 301.7 ± 25.33, 304.8 ± 25.63 and 322.1 ± 45.77 respectively. The morphometric data were not different statistically (p > 0.05). Summing up, the present work showed that there was no alteration in the cellular proliferation of the ileum of diabetic-induced rats supplemented with ascorbic acid.

  1. 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

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

    Scientific Electronic Library Online (English)

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

    2117-21-01

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    Surapaneni Krishna

    2007-01-01

    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.

  4. Differential modulation of xenobiotic-metabolizing enzymes in rats following single and concurrent exposure to chlorpyrifos, arsenic, and ascorbic acid.

    Science.gov (United States)

    Rajpoot, Dinesh Singh; Prakash, Atul; Mandil, Rajesh; Rahal, Anu; Garg, Satish Kumar

    2013-01-01

    The present study was undertaken to evaluate the subacute toxicity of arsenic (As) and chlorpyrifos (CPF) alone or in combination. In addition, the ameliorative effect of ascorbic acid on As and/or CPF-induced hepatic microsomal xenobiotic metabolizing enzymes in rats was examined. Rats were divided into 9 groups of 6 animals each: control (deionized water), vehicle control (groundnut oil), ascorbic acid (100 mg/kg body weight), As (40 ppm in water), CPF (5 mg/kg body weight), As (40 ppm) + CPF (5 mg/kg body weight), As + ascorbic acid, CPF + ascorbic acid, and As + CPF + ascorbic acid. After 28 d of exposure, rats were sacrificed and liver was extracted for isolation of hepatic microsomes. Exposure to As or CPF alone as well as both of these in combination significantly altered microsomal proteins and activity of phase I and phase II xenobiotic-metabolizing enzymes. Cytochrome P-450 and cytochrome b 5 levels and activities of aniline p-hydroxylase (APH) and uridine diphosphate glucuronosyltransferase (UGT) were significantly decreased in groups treated with As, CPF, and As plus CPF, while glutathione S-transferase (GST) was not markedly altered. Enzymatic activity of aminopyrine N-demethylase (ANDM) was also significantly reduced in As- and CPF-only groups. Co-administration of ascorbic acid effectively countered the As- and CPF-induced alterations in xenobiotic-metabolizing enzymes. PMID:24283477

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

    Directory of Open Access Journals (Sweden)

    Marco Iammarino

    2012-04-01

    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.

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

    Science.gov (United States)

    Kalita, Suravi; Verma, Akalesh Kumar; Prasad, Surya Bali

    2014-02-01

    Chlorambucil is an anticancer drug with alkylating and immunosuppressive activities. Considering various reports on the possible antioxidant/protective functions of ascorbic acid (vitamin C), it was aimed at to explore the modulatory effect of ascorbic acid on therapeutic efficacy and toxicity induced by chlorambucil. Dalton's ascites lymphoma tumor serially maintained in Swiss albino mice were used for the present experiments. The result of antitumor activity showed that combination treatment with ascorbic acid and chlorambucil exhibited enhanced antitumor activity with 170% increase in life span (ILS), which is significantly higher as compared to chlorambucil alone (ILS 140%). Analysis of apoptosis in Dalton's lymphoma tumor cells revealed a significantly higher apoptotic index after combination treatment as compared to chlorambucil alone. Blood hemoglobin content, erythrocytes and leukocytes counts were decreased after chlorambucil treatment, however, overall recovery in these hematological values was noted after combination treatment. Chlorambucil treatment also caused morphological abnormalities in red blood cells, majority of which include acanthocytes, burr and microcystis. Combination treatment of mice with ascorbic acid plus chlorambucil showed less histopathological changes in kidney as compared to chlorambucil treatment alone, thus, ascorbic acid is effective in reducing chlorambucil-induced renal toxicity in the hosts. Based on the results, for further development, hopefully into the clinical usage, the administration of ascorbic acid in combination with chlorambucil may be recommended. PMID:24597143

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

    Directory of Open Access Journals (Sweden)

    Noriko Sasaki

    2010-11-01

    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.

  8. [Effects of ascorbic acid on the metabolic fate and the free radical formation of iproniazid].

    Science.gov (United States)

    Matsuki, Y; Hongu, Y; Noda, Y; Kiwada, H; Sakurai, H; Goromaru, T

    1992-12-01

    The effects of ascorbic acid (AA) on the metabolic fate of iproniazid (IPN) and on the free radical intermediates derived from IPN were investigated in rats. After oral administration of IPN with or without AA, the plasma concentration and the urinary excretion of IPN and its metabolites were determined by gas chromatography-mass spectrometry using stable isotope labeled compounds as internal standards. In the excretion of IPN and its metabolites except hydrazine (Hy), the differences between co-administration and single administration were not observed. The excretion of Hy, which is a known hepatotoxic metabolite, decreased clearly in the co-administration of IPN and AA. When IPN and AA were co-administered orally, the profiles of plasma levels of IPN and its metabolites were almost similar after the administration of IPN alone. Furthermore, no differences between i.v. co-administration and i.v. administration alone were observed. These results indicated that AA did not affect both absorption and metabolism of IPN. By the electron spin resonance (ESR) spectroscopy and spin-trapping technique, the ESR signals due to the alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone (4-POBN) adducts induced by isopropylhydrazine (IP-Hy) were two-fold higher than those by IPN in microsomal systems. The free radical formations of IPN and IP-Hy were significantly inhibited by AA in a dose dependent manner. The 4-POBN-trapped radical species generated from IPN and IP-Hy were presumed to be an isopropyl radical by the results of mass spectrometry.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1294718

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

    Science.gov (United States)

    Kviecinski, M R; Pedrosa, R C; Felipe, K B; Farias, M S; Glorieux, C; Valenzuela, M; Sid, B; Benites, J; Valderrama, J A; Verrax, J; Buc Calderon, P

    2012-05-01

    The effects of juglone on T24 cells were assessed in the presence and absence of ascorbate. The EC(50) 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. PMID:22507983

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

    Directory of Open Access Journals (Sweden)

    Tabatabaei S. A.

    2013-11-01

    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.

  11. Ascorbic acid: New role of an age-old micronutrient in the management of periodontal disease in older adults.

    Science.gov (United States)

    Alagl, Adel S; Bhat, Subraya Giliyar

    2015-03-01

    To review the new role of an age-old micronutrient - ascorbic acid - in the management of periodontal disease. Articles pertaining to the topic were searched in PubMed and other search engines from year 1974 to April 2014 with the following key words: "ascorbic acid," "ascorbate," "vitamin C," "periodontal disease," "gingivitis," "periodontitis," "anti-oxidants" and "elderly." Balanced nutrition is an essential factor in the elderly. Modification of nutritional requirement is important to overcome the effect of an unbalanced diet in older individuals as a result of several external and internal host-associated factors. Micronutrient requirements as aging advances could change, and require due attention. Ascorbic acid and its relationship with periodontal disease are very well known. However, recent changes in the concept of understanding the pathogenicity has led to a new path of therapeutic intervention with ascorbic acid in many chronic diseases. Oxidative stress with its associated burden might alter the disease process. In the era of "periodontal medicine," the impact of remote tissue changes on systemic disease has to be taken into serious consideration. Deficiency of nutritional impact on the host, with micronutrient vitamin C detailed in this review with sources, absorption, interaction and its relationship with systemic disease, and thereby the impact on periodontal disease. Ascorbic acid plays an important role in the aging process, and in the maintenance of periodontal health in the elderly. Geriatr Gerontol Int 2015; 15: 241-254. PMID:25407241

  12. Industrialized cashew juices: variation of ascorbic acid and other physicochemical parameters Sucos de caju industrializados: variação no teor de ácido ascórbico e em outros parâmetros físico-químicos

    OpenAIRE

    Christiane de Queiroz Pereira; Flávia Conde Lavinas; Maria Lúcia Mendes Lopes; Vera Lúcia Valente-Mesquita

    2008-01-01

    Commercial cashew apple juice is widely accepted in the Brazilian market. Cashew apple has high content of ascorbic acid, an important nutrient to human beings. Ascorbic acid content in food can be affected by processing and storage conditions. Commercial cashew apple juice samples, ready-to-drink and concentrated, were analyzed. The ascorbic acid content, total titratable acidity, total soluble solids, and pH of the juices were determined during storage at 4 °C after the containers were ope...

  13. Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China); 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); Zhou, Xibin, E-mail: zhouxb@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China)

    2014-05-01

    Highlights: • Trp-GR was synthesized by utilizing a facile ultrasonic method. • The material as prepared had well dispersivity in water and better conductivity than pure GR. • Trp-GR/GCE showed excellent potential for the determination of AA, DA and UA. • The proposed method was applied for the analysis of AA, DA and UA in real samples. - Abstract: A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via ?–? conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA–DA, DA–UA and UA–AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2–12.9 mM, 0.5–110 ?M, and 10–1000 ?M, with the detection limits (S/N = 3) of 10.09 ?M, 0.29 ?M and 1.24 ?M, respectively. Furthermore, the modified electrode was investigated for real sample analysis.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  15. 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.

  16. Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene

    International Nuclear Information System (INIS)

    Highlights: • Trp-GR was synthesized by utilizing a facile ultrasonic method. • The material as prepared had well dispersivity in water and better conductivity than pure GR. • Trp-GR/GCE showed excellent potential for the determination of AA, DA and UA. • The proposed method was applied for the analysis of AA, DA and UA in real samples. - Abstract: A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via ?–? conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA–DA, DA–UA and UA–AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2–12.9 mM, 0.5–110 ?M, and 10–1000 ?M, with the detection limits (S/N = 3) of 10.09 ?M, 0.29 ?M and 1.24 ?M, respectively. Furthermore, the modified electrode was investigated for real sample analysis

  17. 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 fradiation 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)

  18. Ascorbic Acid Biosynthesis and Brackish Water Acclimation in the Euryhaline Freshwater White-Rimmed Stingray, Himantura signifer.

    Science.gov (United States)

    Wong, Samuel Z H; Ching, Biyun; Chng, You R; Wong, Wai P; Chew, Shit F; Ip, Yuen K

    2013-01-01

    L-gulono-?-lactone oxidase (Gulo) catalyzes the last step of ascorbic acid biosynthesis, which occurs in the kidney of elasmobranchs. This study aimed to clone and sequence gulonolactone oxidase (gulo) from the kidney of the euryhaline freshwater stingray, Himantura signifer, and to determine the effects of acclimation from freshwater to brackish water (salinity 20) on its renal gulo mRNA expression and Gulo activity. We also examined the effects of brackish water acclimation on concentrations of ascorbate, dehydroascorbate and ascorbate + dehydroascorbate in the kidney, brain and gill. The complete cDNA coding sequence of gulo from the kidney of H. signifer contained 1323 bp coding for 440 amino acids. The expression of gulo was kidney-specific, and renal gulo expression decreased significantly by 67% and 50% in fish acclimated to brackish water for 1 day and 6 days, respectively. There was also a significant decrease in renal Gulo activity after 6 days of acclimation to brackish water. Hence, brackish water acclimation led to a decrease in the ascorbic acid synthetic capacity in the kidney of H. signifer. However, there were significant increases in concentrations of ascorbate and ascorbate + dehydroascorbate in the gills (after 1 or 6 days), and a significant increase in the concentration of ascorbate and a significant decrease in the concentration of dehydroascorbate in the brain (after 1 day) of fish acclimated to brackish water. Taken together, our results indicate that H. signifer might experience greater salinity-induced oxidative stress in freshwater than in brackish water, possibly related to its short history of freshwater invasion. These results also suggest for the first time a possible relationship between the successful invasion of the freshwater environment by some euryhaline marine elasmobranchs and the ability of these elasmobranchs to increase the capacity of ascorbic acid synthesis in response to hyposalinity stress. PMID:23825042

  19. DNA damage and inhibition of akt pathway in mcf-7 cells and ehrlich tumor in mice treated with 1,4-naphthoquinones in combination with ascorbate.

    Science.gov (United States)

    Ourique, Fabiana; Kviecinski, Maicon R; Felipe, Karina B; Correia, João Francisco Gomes; Farias, Mirelle S; Castro, Luiza S E P W; Grinevicius, Valdelúcia M A S; Valderrama, Jaime; Rios, David; Benites, Julio; Buc Calderon, Pedro; Pedrosa, Rozangela Curi

    2015-01-01

    The aim of this study was to enhance the understanding of the antitumor mechanism of 1,4-naphthoquinones and ascorbate. Juglone, phenylaminonaphthoquinone-7, and 9 (Q7/Q9) were evaluated for effects on CT-DNA and DNA of cancer cells. Evaluations in MCF-7 cells are DNA damage, ROS levels, viability, and proliferation. Proteins from MCF-7 lysates were immunoblotted for verifying PARP integrity, ?H2AX, and pAkt. Antitumor activity was measured in Ehrlich ascites carcinoma-bearing mice. The same markers of molecular toxicity were assessed in vivo. The naphthoquinones intercalate into CT-DNA and caused oxidative cleavage, which is increased in the presence of ascorbate. Treatments caused DNA damage and reduced viability and proliferation of MCF-7 cells. Effects were potentiated by ascorbate. No PARP cleavage was observed. Naphthoquinones, combined with ascorbate, caused phosphorylation of H2AX and inhibited pAkt. ROS were enhanced in MCF-7 cells, particularly by the juglone and Q7 plus ascorbate. Ehrlich carcinoma was inhibited by juglone, Q7, or Q9, but the potentiating effect of ascorbate was reproduced in vivo only in the cases of juglone and Q7, which caused up to 60% inhibition of tumor and the largest extension of survival. Juglone and Q7 plus ascorbate caused enhanced ROS and DNA damage and inhibited pAkt also in Ehrlich carcinoma cells. PMID:25793019

  20. Natural resistance to ascorbic acid induced oxidative stress is mainly mediated by catalase activity in human cancer cells and catalase-silencing sensitizes to oxidative stress

    OpenAIRE

    Klingelhoeffer Christoph; Kämmerer Ulrike; Koospal Monika; Mühling Bettina; Schneider Manuela; Kapp Michaela; Kübler Alexander; Germer Christoph-Thomas; Otto Christoph

    2012-01-01

    Abstract Background Ascorbic acid demonstrates a cytotoxic effect by generating hydrogen peroxide, a reactive oxygen species (ROS) involved in oxidative cell stress. A panel of eleven human cancer cell lines, glioblastoma and carcinoma, were exposed to serial dilutions of ascorbic acid (5-100?mmol/L). The purpose of this study was to analyse the impact of catalase, an important hydrogen peroxide-detoxifying enzyme, on the resistance of cancer cells to ascorbic acid mediated oxidative stress...

  1. Ascorbic acid and pectin in different sizes and parts of citric fruits Ácido ascórbico e pectina em diferentes partes de frutas cítricas de vários tamanhos

    OpenAIRE

    Larissa Akemi Ywassaki; Solange Guidolin Canniatti-Brazaca

    2011-01-01

    Citric fruits - in natura, as frozen pulp or even as juice - are one of the most important Brazilian exportation products. They are a source of ascorbic acid - a potent antioxidant, and pectin, which is used in the food industry and is an important dietary fiber. This project aims to quantify ascorbic acid and pectin contents in citric fruits, commercial oranges and tangerines, comparing them in sizes and varieties. Ascorbic acid amount was measured in juice comparing sizes, varieties and sto...

  2. The synergistic effect of ribose, carnosine, and ascorbic acid on the sensory and physico-chemical characteristics of minced bison meat

    OpenAIRE

    Aliani, Michel; Ryland, Donna; Williamson, Jennifer; Rempel, Natalie

    2013-01-01

    Ingredients such as ascorbic acid used to preserve redness of the raw meat, and carnosine and ribose used for flavor improvement have been incorporated into minced meats to increase consumer acceptance. The objective of this study was to investigate the possible synergistic effect of ascorbic acid, carnosine, and ribose on the sensory and physico-chemical characteristics of minced bison meat. Samples included control (Co) ±1% carnosine (C), 0.1% ascorbic acid (A), 2% ribose (R) (w/w), and co...

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

    Directory of Open Access Journals (Sweden)

    HAMIDAH HAMAMA

    2010-09-01

    Full Text Available 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 simulated by PEG-6000 and regulation of water treatment. During the first experiment, interactions of both osmotic potential and varieties were significant at all variables. Germination percentage and speed of germination were significantly decreased by increasing of osmotic potential. The second experiment showed that interactions of both factors were significant at all variables except vigor index, the length of shoot, primary, and seminal root. The results showed that the ascorbic acid treatment improved the germination percentage, the speed of germination and the vigor index compared with the control, besides the increase in length of shoot, primary and seminal root and number of seminal root. However, the best result was showed by 55 mM ascobic acid. The result of field experiment showed that interactions were not always significant and 55 mM ascorbic acid treatment increased the seedling height, the number of leaves and leaf area but it had no effect on the water deficit and the root length.

  4. Protective role of L-ascorbic acid, N-acetylcysteine and apocynin on neomycin-induced hair cell loss in zebrafish.

    Science.gov (United States)

    Wu, Chia-Yen; Lee, Han-Jung; Liu, Chi-Fang; Korivi, Mallikarjuna; Chen, Hwei-Hsien; Chan, Ming-Huan

    2015-03-01

    Hair cells are highly sensitive to environmental insults and other therapeutic drugs. The adverse effects of drugs such as aminoglycosides can cause hair cell death and lead to hearing loss and imbalance. The objective of the present study was to evaluate the protective activity of L-ascorbic acid, N-acetylcysteine (NAC) and apocynin on neomycin-induced hair cell damage in zebrafish (Danio rerio) larvae at 5 days post fertilization (dpf). Results showed that the loss of hair cells within the neuromasts of the lateral lines after neomycin exposure was evidenced by a significantly lower number of neuromasts labeled with fluorescent dye FM1-43FX observed under a microscope. Co-administration with L-ascorbic acid, NAC and apocynin protected neomycin-induced hair cell loss within the neuromasts. Moreover, these three compounds reduced the production of reactive oxygen species (ROS) in neuromasts exposed to neomycin, indicating that their antioxidant action is involved. In contrast, the neuromasts were labeled with specific fluorescent dye Texas-red conjugated with neomycin to detect neomycin uptake. Interestingly, the uptake of neomycin into hair cells was not influenced by these three antioxidant compounds. These data imply that prevention of hair cell damage against neomycin by L-ascorbic acid, NAC and apocynin might be associated with inhibition of excessive ROS production, but not related to modulating neomycin uptake. Our findings conclude that L-ascorbic acid, NAC and apocynin could be used as therapeutic drugs to protect aminoglycoside-induced listening impairment after further confirmatory studies. PMID:25092119

  5. Ab initio study of the structural properties of ascorbic acid (vitamin C)

    Science.gov (United States)

    Allen, Reeshemah N.; Shukla, M. K.; Reed, Demarcio; Leszczynski, Jerzy

    Geometries of the neutral and ionic tautomeric species of ascorbic acid were optimized at the density functional theory (DFT) level using the B3LYP functional. The radical species were evaluated using the unrestricted B3LYP method. Single-point energy calculations were also performed using the Møller-Plesset (MP2) and unrestricted MP2 (UMP2) methods for the closed-shell and open-shell systems, respectively. The effects of aqueous solution were evaluated using the conducting polarized continuum model (CPCM) and polarized continuum model (PCM). The geometries of most stable radicals in the respective groups were also optimized in the water solution using the CPCM model at the UB3LYP level. All calculation were performed using the 6-311++G(d,p) basis set. The nature of stationary points on the gas phase potential energy surfaces (PESs) was evaluated using vibrational frequency calculations; all geometries characterize local minima. The species obtained by the deprotonation of the O3 site is the most stable monoanion of ascorbic acid. For the radical species, the structure obtained by the dehydrogenation of the O3 site is the most stable monoradical. Among the radical anions, the species obtained by the deprotonation of the O3 site and subsequent dehydrogenation of the O2 site is the most stable in the gas phase and in an aqueous medium. The computed isotropic hyperfine coupling constants of this species were found to be in good agreement with the experimental data. Our investigation also supports the earlier findings that the oxidized species of ascorbic acid in water solution by the OH? radical is radical anion of the AAO?3O-2 form. The spin densities and molecular electrostatic potentials are also discussed.

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

    Science.gov (United States)

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

    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.

  7. L-Ascorbic acid and L-galactose are sources for oxalic acid and calcium oxalate in Pistia stratiotes.

    Science.gov (United States)

    Keates, S E; Tarlyn, N M; Loewus, F A; Franceschi, V R

    2000-02-01

    Axenic Pistia stratiotes L. plants were pulse-chase labeled with [14C]oxalic acid, L[1-14C]ascorbic acid, L-6-14C]ascorbic acid, D-[1-14C]erythorbic acid, L-[1-14C]galactose, or [1-14C]glycolate. Specific radioactivities of L-ascorbic acid (AsA), free oxalic acid (OxA) and calcium oxalate (CaOx) in labeled plants were compared. Samples of leaf tissue were fixed for microautoradiography and examined by confocal microscopy. Results demonstrate a biosynthetic role for AsA as precursor of OxA and its crystalline deposition product, CaOx, in idioblast cells of P. stratiotes and support the recent discovery of Wheeler, Jones and Smirnoff (Wheeler, G.L., Jones M.A., & Smirnoff, N. (1998). The biosynthetic pathway of vitamin C in higher plants. Nature, 393, 365-369) that L-galactose is a key intermediate in the conversion of D-glucose to AsA in plants. D-[1-14C]erythorbic acid (a diastereomeric analog of AsA) is utilized also by P. stratiotes as a precursor of OxA and its calcium salt deposition product in idioblasts. Labeled OxA is rapidly incorporated into CaOx in idioblasts, but microautoradiography shows there is also significant incorporation of carbon from OxA into other components of growing cells, contrary to the dogma that OxA is a relatively stable end product of metabolism. Glycolate is a poor substrate for synthesis of OxA and CaOx formation, further establishing AsA as th immediate precursor in the synthesis of OxA used for calcium precipitation in crystal idioblasts. PMID:10731019

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

    Energy Technology Data Exchange (ETDEWEB)

    Abhilash, P.A.; Harikrishnan, R.; Indira, M., E-mail: indiramadambath@gmail.com

    2014-01-15

    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-?{sub 1} and IL-6 were also altered in ethanol group. The expressions of fibrosis markers ?-SMA, ?{sub 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.

  9. 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

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

    DEFF Research Database (Denmark)

    Mariotti, Salomé; Granby, Kit

    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.

  11. [Results of a phase I clinical trial of "theraphthal + ascorbic acid" catalytic system].

    Science.gov (United States)

    Garin, A M; Gorbunova, V A; Gershanovich, M L; Manziuk, L V; Borodkina, A G; Breder, V V; Karmanovskaia, O B; Zubrikhina, G N; Madzhuga, A V; Zimakova, N I; Trapeznikov, N N

    2001-01-01

    Phase-I clinical studies of teraphtal and a "teraphtal + ascorbic acid" catalytic system have been completed. The dose-limiting toxicity and maximum tolerable dose were not reached even at the end of maximal dose trials. No side-effects characteristic of antitumor cytostatic drugs were registered. The gravest side-effect ever recorded was a collapse which could not be linked to teraphtal dosage and was probably caused by hypersensitivity to the drug. The drug was recommended for phase II trials. PMID:11826487

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

    Directory of Open Access Journals (Sweden)

    Fiona E. Harrison

    2014-04-01

    Full Text Available 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.

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

    OpenAIRE

    Do Carmo, Devaney R.; Da Silva, Ricardo M.; Stradiotto, Nelson R.

    2004-01-01

    Iron nitroprusside, Fe(II)NP was incorporated into a carbon paste electrode and the electrochemical studies were performed by cyclic voltammetry. The cyclic voltammogram of the modified electrode, Fe(II)NP showed two redox couples ( E½ox)1 = 0.24 and (E½ox)2 = 0.85 V vs. SCE attributed to Fe(II)/Fe(III) and Fe(II)(CN)5NO / Fe(III)(CN)5NO, respectively. The redox couple at (E½ox)1 = 0.24 V presents an electrocatalytic response for ascorbic acid. The modified paste electrode exhibits a decre...

  14. Photometric starch-iodine determination in plant materials as influenced by ascorbic acid. Critical remarks

    OpenAIRE

    Bogus?aw Samotus; El?bieta Doerre; Adam ?widerski; Andrzej ?cigalski

    1994-01-01

    Following the work of Sharma et al. (1990) on the interference of ascorbic acid (AA) with starch-iodine reaction, the present authors repeated it, giving a proper explanation of the influence of AA in this reaction. AA oxidizes iodine-iodide (I-KI) reagent which makes impossible to form the blue complex with starch. Three measures are suggested to overcome the interference of AA: 1) to titrate starch solution with I-KI reagent and thus work out an I-KI amount for development of blue coloratio...

  15. Simultaneous Chronoamperometric Sensing of Ascorbic Acid and Acetaminophen at a Boron-Doped Diamond Electrode

    OpenAIRE

    Ciprian Radovan; Codruţa Cofan

    2008-01-01

    Cyclic voltammetry (CV) and chronoamperometry (CA) have been used to sense and determine simultaneously L-ascorbic acid (AA) and acetaminophen (AC) at a boron-doped diamond electrode (BDDE) in a Britton-Robinson buffer solution. The calibration plots of anodic current peak versus concentration obtained from CV and CA data for both investigated compounds in single and di-component solutions over the concentration range 0.01 mM – 0.1 mM proved to be linear, with very good correlati...

  16. Thermal Inactivation of Aeromonas hydrophila As Affected by Sodium Chloride and Ascorbic Acid

    OpenAIRE

    Stecchini, Mara Lucia; Sarais, Ileana; Giomo, Andrea

    1993-01-01

    The combined effects of sodium chloride (0, 1.0, 1.5, and 3.0%) and ascorbic acid (0, 1.0, and 2.0 mmol/liter) with mild heat (46°C) on the survival of Aeromonas hydrophila were evaluated. Because of the nonlinear nature of the survivor curves obtained, several equations yielding an R2 (coefficient of multiple determination) of ? 1 were tested. The equation that most closely fit the curvature of the observed data set was a hyperbolic function. Equation coefficients were combined to obtain ...

  17. SCREEN-PRINTED ELECTRODE MODIFIED WITH SILVER HEXACY ANOFERRATE-NAFION® FOR ASCORBIC ACID DETERMINATION

    OpenAIRE

    Mattos, I. L.; Padilla, F.; Zagal, J. H.; Falcao, E. H. L.; Segura, R.

    2011-01-01

    A flow injection system using a new and/or re-used graphite screen-printed electrode modified with silver hexacyanoferrate and a Nafion® polymer layer (AgHCF/GSPE) was employed for the determination of ascorbic acid in orange juice and drugs samples. Both modified electrodes showed an initial sensitivity of 0.015 A.cm²?.M¹?, with a linear response over the range from 50 to 300 mg L¹ , relative standard deviations smaller than 2%, detection and quantification limits of c.a. 5.0...

  18. Silver Colloid Synthesis in Linear and Branched Anionic Polymer Matrices by Using Ascorbic Acid as Reductant

    Directory of Open Access Journals (Sweden)

    Korychenska O.

    2013-09-01

    Full Text Available Silver colloids were synthesized in linear and branched anionic polymer matrices at different pH reducing by ascorbic acid. The template role of the host polymers in anionic form was studied at pH = 7 and pH = 12. Linear Polyacrylamide and star-like copolymers Dextran-graft-Polyacrylamide after alkaline hydrolysis were used as matrices. Silver colloids were studied by UV-Vis spectrophotometry just after synthesis and in 3 months. It is shown that branched polymer matrices are more efficient in comparison with linear one for in situ silver nanoparticle synthesis. The pH value affects the process of formation was investigated.

  19. Ascorbic acid and citric flavonoids for broilers under heat stress: effects on performance and meat quality

    OpenAIRE

    Jem, Pen?a; Sl, Vieira; Lo?pez, J.; Rn, Reis; Barros, R.; Fvf, Furtado; Px, Silva

    2008-01-01

    The aim of this study was to evaluate the effects of increasing doses of ascorbic acid (AA) and citric flavonoids (quercetin and rutin) on the performance and meat quality characteristics of broilers submitted to cyclic heat stress. Four-hundred one-day-old female Ross 308 were housed in 40 battery cages a in temperature controlled room. Treatments consisted of 0, 250, 500, and 1000 g/ton on of AA + citric flavonoids. Birds were fed ad libitum until 32 day of age. Beginning on day 14 post-hat...

  20. Ascorbic acid protects against endogenous oxidative DNA damage in human sperm.

    OpenAIRE

    Fraga, C. G.; Motchnik, P. A.; Shigenaga, M. K.; Helbock, H. J.; Jacob, R. A.; Ames, B. N.

    1991-01-01

    Damage to the DNA of germ cells can lead to mutation, which may result in birth defects, genetic diseases, and cancer. The very high endogenous rate of oxidative DNA damage and the importance of dietary ascorbic acid (AA) in preventing this damage has prompted an examination of these factors in human sperm DNA. The oxidized nucleoside 8-hydroxy-2'-deoxyguanosine (8-oxo-7,8-dihydro-2'-deoxyguanosine; oxo8dG), 1 of approximately 20 major products of oxidative damage to DNA, was measured in DNA ...

  1. Kinetics of ascorbic acid degradation in green asparagus during heat processing.

    Science.gov (United States)

    Esteve, M J; Frígola, A; Martorell, L; Rodrigo, C

    1998-11-01

    The effect of heating on ascorbic acid in green asparagus during a simulated retort operation was investigated. The asparagus was heated in trays of ethylene-vinyl alcohol copolymer for selected time intervals at four temperatures ranging from 110 to 125 degrees C. It was found that the rate of degradation followed first-order kinetics. Kinetic parameters were obtained by using two least squares methods. The activation energy and z value were 35 kcal/mol and 20 degrees C, respectively. PMID:9829197

  2. Long-distance transport of L-ascorbic acid in potato

    OpenAIRE

    Alberino Salvatore; Hancock Robert D; Tedone Luigi; Haupt Sophie; Viola Roberto

    2004-01-01

    Abstract Background Following on from recent advances in plant AsA biosynthesis there is increasing interest in elucidating the factors contributing to the L-ascorbic acid (AsA) content of edible crops. One main objective is to establish whether in sink organs such as fruits and tubers, AsA is synthesised in situ from imported photoassimilates or synthesised in source tissues and translocated via the phloem. In the current work we test the hypothesis that long-distance transport is involved i...

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

    OpenAIRE

    Samuel Tilahun; Pandiyan Paramaguru; Kandhasamy Rajamani

    2013-01-01

    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...

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

    Directory of Open Access Journals (Sweden)

    I.V. Ogungbe

    2008-01-01

    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.

  5. [Screening for the new formulation of 25% ascorbic acid injection and studies on its stability].

    Science.gov (United States)

    Guo, Y; Chen, X; Zhao, Y; Sun, J

    1996-09-01

    Two optimum new formulation of 25% ascobic Acid injection were selected by screening with the method of orthogomal design. To estimate the stability of these new formulations, samples were subjected to accelerated stability test at elevated temperatures. The rats of coloration and variation in the concentration of the new formulation under anaerobic degradation were studied. Experimental results indicate that the rule of coloration of ascorbic acid injection may be represented by the following regression equation T = T(o)-kt2 where To is the initial transmittance of the injection, T denotes the transmittance at time t, and k denotes the regression coefficient. The variation in the concentration of the two new formulations under amaerobic degradation was found to proceed in the pseudo-zero order reaction. The discoloration and content of ascorbic acid for two injections were predicted by accelerated stability test with the classical isothermal method and one-point method respectively. The discoloration shelf-life was about 39 months for R I and 36 months for R II, the content shelf-life about 40 months for R I and 38 months for R II respectively. PMID:9389075

  6. Betalain, Acid ascorbic, phenolic contents and antioxidant properties of purple, red, yellow and white cactus pears.

    Science.gov (United States)

    Sumaya-Martínez, María Teresa; Cruz-Jaime, Sandra; Madrigal-Santillán, Eduardo; García-Paredes, Juan Diego; Cariño-Cortés, Raquel; Cruz-Cansino, Nelly; Valadez-Vega, Carmen; Martinez-Cardenas, Leonardo; Alanís-García, Ernesto

    2011-01-01

    Commercialization of cactus pears based on their antioxidant properties can generate competitive advantages, and these can turn into business opportunities and the development of new products and a high-value ingredient for the food industry. This work evaluated the antioxidant activities (1,1-diphenyl-2-picrylhydrazyl radical-scavenging, protection against oxidation of a ?-carotene-linoleic acid emulsion, and iron (II) chelation), the content of total phenolic compounds, ascorbic acid, betacyanin, betaxanthin and the stability of betacyanin pigments in presence of Cu (II)-dependent hydroxyl radicals (OH•), in 18 cultivars of purple, red, yellow and white cactus pear from six Mexican states. Our results indicated that the antiradical activities from yellow and white cactus pear cultivars were not significantly different (p Zacatecas showed the highest antioxidant activity. The free radical scavenging activity for red cactus pears was significantly correlated (p < 0.05) to the concentration of total phenolic compounds (R(2) = 0.90) and ascorbic acid (R(2) = 0.86). All 18 cultivars of cactus pears studied showed significant chelating activity of ferrous ions. The red and purple cactus pears showed a great stability when exposed to OH•. PMID:22072899

  7. Protective action of ascorbic acid and sulfur compounds against acetaldehyde toxicity: implications in alcoholism and smoking.

    Science.gov (United States)

    Sprince, H; Parker, C M; Smith, G G; Gonzales, L J

    1975-05-01

    Acetaldehyde is a toxic substance common to heavy drinking of alcohol and heavy smoking of cigarettes. It has been implicated thereby in diseases of the cardiovascular, respiratory, and central nervous systems. Protection against acetaldehyde toxicity (i.e. anesthesia and lethality) was studied in rats by oral intubation of test compounds 30-45 minutes prior to oral intubation of a standardized oral LD 90 dose (18 millimoles/kilogram) of acetaldehyde. Animals were monitored for anesthesia (loss of righting reflexes) and lethality for 72 hours. A total of 18 compounds was tested. L-ascorbic acid at 2 millimoles/kilogram (mM/kg) showed moderate protection against anesthesia and marked protection against lethality. Greatest protection against anesthesia and lethality was obtained at 2 m M/kg with each of the following: L-cysteine, N-acetyl-L-cysteine, thiamin-HCl, sodium metabisulfite, and L-cysteic acid. A combination of L-ascorbic acid with L-cysteine, and thiamin-HCl at reduced dose levels (2.0, 1.0 and 0.3 mM/kg, respectively) gave virtually complete protection. A detailed literature review is presented of the rationale and significance of these findings. Our findings could point the way to a possible build-up of natural protection against the chronic body insult of acetaldehyde arising from heavy drinking of alcohol and heavy smoking of cigarettes. PMID:1171591

  8. Complexations of polyoligothiophenes films with transition metals, and their use for electrocatalysis of ascorbic acid

    Science.gov (United States)

    Maouche, N.; Chelli, S.; Nessark, B.; Aeiyach, S.

    2009-11-01

    Chemically modified electrodes prepared by electropolymerization of oligothiophenes such as: 2,2'-bithiophene (BT), 2,2'-bithiophene-5-carboxylic acid (BTCA) and terthiophene aldehyde (TTCHO) on platinum (Pt) electrodes, in acetonitrile solution containing 0.1 M tetrabutylammonium perchlorate (TBAP) and 0.01 M of monomer, are characterized by cyclic volammetry (CV), and X-ray photoelectron spectroscopy (XPS) measurements. By immersing the prepared modified electrodes in transition metals (Cu2+, Co2+ and Ag+) solutions, the metal ions were complexed with films. The electrochemical response shows clearly, the presence of oxidation and reduction peaks corresponding to metallic couple redox. XPS technique reveal that the films complexed with metal ions and determine the mode of the connection with film's atoms. The obtained polyoligothiophenes-metal modified electrodes exhibited good electrocatalytic properties towards ascorbic acid (AA) oxidation after their complexation with metallic ions. The electrocatalytic response was evaluated by cyclic voltammetry with regard to the film nature, the metallic ion nature, immersion time, ascorbic acid concentration, and other variables. The results reveal that the catalytic activity of Ag+ complexed with BTCA thin-film is the best toward AA oxidation and it can be detected a very low concentration (?1 ?M), of AA in a solution which can be utilized as an efficient electrochemical sensor.

  9. Kolaviron and L-ascorbic Acid attenuate chlorambucil-induced testicular oxidative stress in rats.

    Science.gov (United States)

    Olayinka, Ebenezer Tunde; Ore, Ayokanmi

    2014-01-01

    Chlorambucil (4-[4-[bis(2-chloroethyl)amino]phenyl]butanoic acid) is an alkylating agent, indicated in chronic lymphocytic leukaemia. Kolaviron (KV), a biflavonoid complex from Garcinia kola, and L-ascorbic acid (AA) are known to protect against oxidative damage in vivo. This study evaluates the protective capacity of KV and AA on chlorambucil-induced oxidative stress in the testes of rat. Twenty male Wistar rats (180-200?g) were randomized into four groups: I: control, II: chlorambucil (0.2?mg/kg b.w.), III: 0.2?mg/kg chlorambucil and 100?mg/kg KV, and IV: 0.2?mg/kg chlorambucil and 100?mg/kg AA. After 14 days of treatments, results indicated that chlorambucil caused significant reduction (P chlorambucil-treated rats relative to control. Testicular MDA and activities of ALP, LDH, and ACP were increased significantly by 53%, 51%, 64%, and 70%, respectively, in the chlorambucil-treated rat. However, cotreatment with KV and AA offered protection and restored the levels of vitamin C, GSH, and MDA as well as SOD, CAT, GST, ACP, ALP, and LDH activities. Overall, kolaviron and L-ascorbic acid protected against chlorambucil-induced damage in the testes of the rat. PMID:25309592

  10. Efficient voltammetric discrimination of free bilirubin from uric acid and ascorbic acid by a CVD nanographite-based microelectrode.

    Science.gov (United States)

    Taurino, Irene; Van Hoof, Viviane; Magrez, Arnaud; Forró, László; De Micheli, Giovanni; Carrara, Sandro

    2014-12-01

    We report a novel electrochemical sensor based on nanographite grown on platinum microelectrodes for the determination of bilirubin in the presence of normal concentrations of albumin. The albumin is a protein with an intrinsic ability to bind the bilirubin therefore reducing the concentration of the free electroactive metabolite in human fluids. In addition, the proposed device permits the discrimination of free bilirubin from two interferents, uric acid and ascorbic acid, by the separation of their oxidation peaks in voltammetry. Preliminary measurements in human serum prove that the proposed nanostructured platform can be used to detect bilirubin. PMID:25159430

  11. Role of cellular antioxidants (glutathione and ascorbic acid) in the growth and development of wild carrot suspension cultures

    International Nuclear Information System (INIS)

    Determinations of endogenous glutathione (GSH), glutathione disulfide (GSSG), ascorbic acid (AA) and dehydroascorbic acid (DHA) in proliferating and developing wild carrot cultures showed that lower levels of GSH and AA were associated with developing cultures. The GSSG and DHA levels did not account for the changes in the levels of antioxidants between proliferating and developing cultures. Studies were designed to test an observed auxin (2,4-Dichlorophenoxyacetic acid, 2,4-D)-antioxidant association. Two fractions (embryo and less developed) were obtained by screening developed cultures which were previously grown in the presence of 14C-2, 4-D. The embryo fraction had a lower concentration of 14C than the less developed fraction, supporting the association, since the two fractions showed this relationship with respect to GSH and AA concentrations. Determinations of GSH and AA levels of cells grown in various concentrations of 2,4-D showed the association, decreases in the 2,4-D concentration correlated with decreases in the GSH and AA concentrations. The existence of a respiratory pathway involving GSSG reductase, DHA reductase, and AA oxidase was investigated to test whether inhibition of AA oxidase by 2,4-D could explain the auxin-antioxidant association; however, AA oxidase activity was not detected

  12. [Antinicrobial, antiexudative and immunotropic properties of chlorhexidine bigluconate in combination with zinc oxide, succinic and ascorbic acids].

    Science.gov (United States)

    Savateeva-Liubimova, T N; Lesiovskaia, E E; Sivak, K V; Stosman, K I; Stro?kova, G S; Rassokha, T A; Rudenko, L I

    2011-01-01

    Optimal combination of chlorhexidine bigluconate with ascorbic acid, succinic acid, and zinc oxide was found as a result of comparative trials. The composition shows antioxidative effects and is capable of initiating antibody producing and phagocytosis. This combination can be used as an active substance of orodispersible tablets for the treatment respiratory tract infections. PMID:21476286

  13. Effects of ascorbic acid enrichment by immersion of rainbow trout (Oncorhynchus mykiss, Walbaum 1792) eggs and embryos

    Science.gov (United States)

    Falahatkar, B.; Dabrowski, K.; Arslan, M.; Rinchard, J.

    2006-01-01

    This study was conducted to examine the effects of different forms and concentrations of ascorbic acid (vitamin C), and different enrichment times (24 and 48 h post ovulation) on egg, embryo and alevin ascorbate concentrations and survival of rainbow trout (enrichment was at the ova stage). In experiments 1 and 2, fertilized eggs were immersed in water containing ascorbate at 0 (control), 100, 1000 mg L-1 l-ascorbic acid (AA) and 2000 mg L -1 l-ascorbyl monophosphate (AP). In experiment 3, 0 (control), 500 and 1000 mg L-1 AA neutralized (N) with NaOH, 1000 mg L-1 AA non-neutralized (NN), 1000 and 2000 mg L-1 AP immersions were used. The mean total ascorbic acid (TAA) and dehydroascorbic acid (DHA) concentrations were measured before fertilization, at 3 and 24 h after fertilization, at the eyed stage, and in hatched alevins. We observed significant differences in TAA concentration at different immersion levels at 3 and 24 h after fertilization. Survival decreased significantly depending on the level of vitamin C, pH of the solutions and immersion time. We suggest that when broodstock rainbow trout do not have enough vitamin C in their ovaries, immersion of eggs in 1000 mg L-1 of neutralized AA may be useful. ?? 2006 Blackwell Publishing Ltd.

  14. Influence of poly(ethylene glycol)-alpha-cyclodextrin complexes on stabilization and transdermal permeation of ascorbic acid.

    Science.gov (United States)

    Davaran, Soodabeh; Hanaee, Jalal; Rashidi, Mohammad R; Valiolah, Fatemeh; Hashemi, Mahdi

    2006-09-01

    The present study was conducted to investigate the effect of poly(ethylene glycol)-alpha-cyclodextrin (alpha-CD) complexes on stabilization and cutaneous permeation of ascorbic acid from specially prepared transdermal patches. Poly(ethylene glycol) citrate (6-armPEG) and its inclusion complex with alpha-CD were prepared and used for preparation of the transdermal patches. Duro-Tak 87-2979 was taken as an adhesive matrix in combination with ascorbic acid. A diffusion cell with an artificial membrane was used to evaluate the absorption of ascorbic acid from the patches. The influence of drug release of alpha-CD and two types of its PEG complexes (as the novel permeation enhancers) was tested. The 6-armPEG-alpha-CD complex consisting of a PEG-citric acid ester at a concentration of 0.08-0.1% (w/v) is a suitable stabilizer for ascorbic acid during UV assay. The release studies showed that the type of enhancer is important in diffusion of the drug across membrane. Furthermore, the diffusion of ascorbic acid was considerably enhanced in the presence of 6-armPEG-alpha-CD complex. Inclusion complexes of 6-armPEG with alpha-CD at a concentration of 0.08-0.1% (w/v) is a suitable stabilizer for UV method of assay. The present data suggest that 6-armPEG-alpha-CD complex is also useful in enhancing the release of ascorbic acid from the acrylic type pressure sensitive adhesives. PMID:16739182

  15. Effects of gamma irradiation and storage temperature on carotenoids and ascorbic acid content of mangoes on ripening

    International Nuclear Information System (INIS)

    Synthesis and accumulation of carotenoids in the flesh of Alphonso mangoes on ripening was found to be maximal in fruits stored at tropical ambient temperatures (280 to 320C). Gamma irradiation of preclimacteric fruits at 25 krad did not affect the formation of carotenoids. Storage of preclimacteric fruits either irradiated or unirradiated at 7 to 200C for 16 to 43 days caused a substantial reduction in carotenoid formation even when these fruits were subsequently ripened under optimal conditions. Regardless of storage temperature, carotenes always exceeded xanthophylls in the ripe fruits and, in general, irradiated fruits showed higher levels of carotenes in comparison with unirradiated samples. Ascorbic acid loss during ripening was maximum at ambient temperatures while lengthy storage at low temperatures caused a net increase in ascorbic acid levels. Irradiation seemed to accentuate the loss in ascorbic acid during ripening. (author)

  16. Simultaneous detection of dopamine and ascorbic acid in urine using the H-point standard addition method

    Science.gov (United States)

    Hashem, E. Y.; El-Zohry, Ahmed M.

    2012-07-01

    A highly sensitive H-point standard addition method (HPSAM) was investigated for identification of dopamine and ascorbic acid in some synthetic and pharmaceutical samples in an aqueous medium at pH 9.2 using a universal buffer. The most suitable wavelengths for dopamine and ascorbic acid detection are 260:271 nm and 248:270 nm respectively. Recovery values are between 99.0-101 %. Also, the effect of most common interferents was studied. Detection ranges for dopamine and ascorbic acid are 2·10-6-5·10-5 M and 6·10-6-3·10-5 M respectively with an RSD range between 1.3 and 2.0 %. The method was used to determine both reagents in real and synthesized samples.

  17. Effect of ascorbic acid on reduced glutathione level in arsenic-loaded isolated liver tissues of rat

    Directory of Open Access Journals (Sweden)

    Beauty Saha

    2006-12-01

    Full Text Available Isolated liver tissues of rat were loaded with trivalent arsenic and were exposed in presence and absence of ascorbic acid. The amount of reduced glutathione (GSH in normal liver tissue was 52.0 ? 0.2 ?g/g protein. Addition of arsenic to the tissues reduced the amount of GSH to 11.5 ? 0.3 ?g/g protein. But when the arsenic loaded liver tissues were incubated with ascorbic acid at the concentration of 20 ?g/ml, the amount of GSH was 14.2 ? 0.1 ?g/g protein. There was 22.6% increase of GSH level which was statistically significant (p<0.001 when compared with arsenic alone. This study suggests that ascorbic acid increased the GSH level in arsenic-treated rat's liver.

  18. Sol-gel process for preparing YBa2Cu4O8 precursors from Y, Ba, and Cu acidic acetates/ammonia/ascorbic acid systems

    International Nuclear Information System (INIS)

    Sols were prepared by addition of ammonia to acidic acetate solutions of Y3+, Ba2+, and Cu2+. Ascorbic acid was added to a part of the sol. The resultant sols were gelled to a shard, a film, or microspheres by evaporation at 60 C or by extraction of water from drops of emulsion suspended in 2-ethylhexanol-1. Addition of ethanol to the sols facilitated the formation of gel films, fabricated by a dipping technique, on glass or silver substrates. At 100 C, gels that were formed in the presence of ascorbic acid were perfectly amorphous, in contrast to the crystalline acetate gels. Conversion of the amorphous ascorbate gels to final products was easier than for the acetate gels. The quality of coatings prepared from ascorbate gels was superior to that of acetate gel coatings

  19. Modulation of LXR-? and the effector genes by Ascorbic acid and Statins in psoriatic keratinocytes.

    Science.gov (United States)

    Soodgupta, Deepti; Kaul, Deepak; Kanwar, A J; Parsad, Davinder

    2014-12-01

    Recent studies have revealed critical roles that nuclear receptors like LXR-? (Liver X Receptor- alpha) plays as a class of post-transcriptional gene regulator in skin development and diseases. Keeping in view the fact that LXR-? plays crucial role in keratinocyte proliferation and differentiation, it becomes imperative to dissect the pathways and role of LXR-? genomics in the pathogenesis of psoriasis with ultimate aim to explore novel preventive/therapeutic strategies as treatment options. To explore the effects of agonists and activators of LXR-? on its own gene expression and the putative targets in psoriatic keratinocytes. Identification of promoter sequences for (vitamin D receptor) VDR and Catalase were done using in silico analysis followed by ?-galactosidase (?-gal) reporter plasmid assay in keratinocytes from clinically heathy subjects. Determination of relative levels of LXR-?,VDR and catalase in control versus treated cells upon activation of LXR-? with Atorvastatin + 22R hydroxycholestrol and Ascorbic acid + 22R hydroxycholestrol was done by PCR and Cell Proliferation Assay. The cells transfected with the reporter plasmid element for VDR and catalase showed more than 5 and 4 fold increase respectively in the ?-gal activity compared to the control. An increase of 55% in LXR-? gene expression at RNA level was observed in Atorvastatin + 22-R hydroxycholestrol compared to 24% in Ascorbic acid + 22-ROH cholesterol. The expression of the VDR and Catalase was significantly increased in both treated keratinocytes compared to its normal counterpart. PMID:25283515

  20. Ascorbic acid stabilization of Re-188- and I-131-radiolabeled peptides for radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Guhlke, S.; Sartor, J.; Bender, H.; Biersack, H.J. [Bonn Univ. (Germany). Dept. of Nuclear Medicine; Zamora, P.O. [Bonn Univ. (Germany). Dept. of Nuclear Medicine]|[RhoMed Inc., Albuquerque, NM (United States); Knapp, F.F. Jr. [Oak Ridge National Lab. (ORNL), TN (United States). Nuclear Medicine Group; Rhodes, B.A. [RhoMed Inc., Albuquerque, NM (United States)

    1997-12-31

    Re-188 labeled RC-160 [ cyclic NH{sub 2}-(D)-Phe-Cys-Tyr-(D)-Trp-Lys-Val-Cys-Trp-NH{sub 2} ] cyclic NH is a radiolabeled somatostatin analog which is being explored for its potential as a local/regionally administered radiotherapeutic agent targeting somatostatin-receptor-positive tumors. The stability of {sup 188}Re-RC-160 towards radiolytic effects is a prerequisite for the success of such an approach. High radiation flux was found to result in radiolysis of the peptide, but addition of ascorbic acid to preparations of RC-160 and also somatostatin-14 was found to stabilize these peptides minimizing these radiolytic effects. Subsequent to ascorbic acid stabilization, {sup 188}Re-RC-160 was determined in vitro and in vivo to bind to somatostatin-receptor-positive cells (NCI-H69 human small cell lung carcinoma) but not to receptor-negative cells (Raji, Burkitt`s lymphoma). The comparative binding of Re-188 labeled RC-160 or CTOP [ cyclic NH{sub 2}-(D)-Phe-CysTyr-(D)-Trp-Orn-Thr-Pen-Thr-ol], a {mu}-opiod-receptor antagonist used as a negative control compound, was also determined in vitro and in vivo using NCI-H69 cells as targets. {sup 188}Re-RC-160 demonstrated a higher amount of net binding in vitro and in vivo compared to {sup 188}ReCTOP. (orig.)

  1. Hepato-protective effect of ascorbic acid on oxidative stress in mic exposed to cypermethrin

    International Nuclear Information System (INIS)

    To evaluate protective effect of ascorbic acid on liver parameters in mice exposed to Cypermethrin. Study Design:Laboratory based randomized control trial. Place and Duration of Study: Research was conducted in Army Medical College's biochemistry and molecular biology department in association with department of pathology, Army Medical College, Rawalpindi and National Institute of Health, Islamabad, Pakistan from 19 May 2013 to 17 June 2013. Material and Methods: Thirty albino mice of Balb/C strain weighing 40-45g were randomly divided into three groups. Each group comprised 10 mice. Control group A which received normal diet. Cypermethrin experimental group B received cypermethrin with normal diet experimental group C which received cypermethrin and vitamin C with normal diet. This process continued for 28 days. After this duration serum alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST) values were determined. Results: Serum ALT and AST levels were significantly increased in group B as compared to group A (p< .001). ALT levels of group A and group C were insignificant (p= 0.473). AST levels of group A and C were significantly different (p< 0.01). Conclusion: Ascorbic acid can protect liver from Cypermethrininduced oxidative stress in mice. (author)

  2. Comparative evaluation of polymeric and waxy microspheres for combined colon delivery of ascorbic acid and ketoprofen.

    Science.gov (United States)

    Maestrelli, F; Zerrouk, N; Cirri, M; Mura, P

    2015-05-15

    The goal of this work was to combine the ketoprofen anti-inflammatory effect with the ascorbic acid antioxidant properties for a more efficient treatment of colonic pathologies. With this aim, microspheres (MS) based on both waxy materials (ceresine, Precirol(®) and Compritol(®)) or hydrophilic biopolymers (pectine, alginate and chitosan) loaded with the two drugs were developed, physicochemically characterized and compared in terms of entrapment efficiency, in vitro release profiles, potential toxicity and drug permeation properties across the Caco-2 cell line. Waxy MS revealed an high encapsulation efficiency of ketoprofen but a not detectable entrapment of ascorbic acid, while polymeric MS showed a good entrapment efficiency of both drugs. All MS need a gastro-resistant coating, to avoid any premature release of the drugs. Ketoprofen release rate from polymeric matrices was clearly higher than from the waxy ones. In contrast, the ASC release rate was higher, due to its high hydro-solubility. Cytotoxicity studies revealed the safety of all the formulations. Transport studies showed that the ketoprofen apparent permeability increased, when formulated with the different MS. In conclusion, only polymeric MS enabled an efficient double encapsulation of both the hydrophilic and lipophilic drugs, and, in addition, presented higher drug release rate and stronger enhancer properties. PMID:25746948

  3. The effect of high ascorbic acid supplementation on body iron stores.

    Science.gov (United States)

    Cook, J D; Watson, S S; Simpson, K M; Lipschitz, D A; Skikne, B S

    1984-09-01

    The level of assimilation of dietary iron is believed to have an important influence on iron status. To examine the effect of enhancing the availability of dietary iron on iron balance, 17 adult volunteer subjects were given 2 g of ascorbic acid daily with meals for 16 weeks. Serum ferritin levels before and after the study averaged 46 and 43 micrograms/L, respectively, indicating a negligible effect on iron stores. When vitamin C supplementation was continued for an additional 20 months in five iron-replete and four iron-deficient subjects, serum ferritin determinations again failed to indicate any significant effect of the vitamin C on iron reserves. These findings were not explained by intestinal adaptation to the enhancing effect of the vitamin, because radioisotopic measurements of nonheme iron absorption showed no reduction in the enhancing effect of 1 g of ascorbic acid after four months of megadoses of vitamin C. It is concluded that altering the availability of nonheme dietary iron has little effect on iron status when the diet contains substantial amounts of meat. PMID:6466873

  4. The effect of high ascorbic acid supplementation on body iron stores

    Energy Technology Data Exchange (ETDEWEB)

    Cook, J.D.; Watson, S.S.; Simpson, K.M.; Lipschitz, D.A.; Skikne, B.S.

    1984-09-01

    The level of assimilation of dietary iron is believed to have an important influence on iron status. To examine the effect of enhancing the availability of dietary iron on iron balance, 17 adult volunteer subjects were given 2 g of ascorbic acid daily with meals for 16 weeks. Serum ferritin levels before and after the study averaged 46 and 43 micrograms/L, respectively, indicating a negligible effect on iron stores. When vitamin C supplementation was continued for an additional 20 months in five iron-replete and four iron-deficient subjects, serum ferritin determinations again failed to indicate any significant effect of the vitamin C on iron reserves. These findings were not explained by intestinal adaptation to the enhancing effect of the vitamin, because radioisotopic measurements of nonheme iron absorption showed no reduction in the enhancing effect of 1 g of ascorbic acid after four months of megadoses of vitamin C. It is concluded that altering the availability of nonheme dietary iron has little effect on iron status when the diet contains substantial amounts of meat.

  5. Development of iodimetric redox method for routine estimation of ascorbic acid from fresh fruit and vegetables

    International Nuclear Information System (INIS)

    The iodimetric method (Im) is developed for rapid estimation of ascorbic acid from fresh fruit and vegetables. The efficiency of Im was compared with standard with standard dye method (Dm) utilizing a variety of model solutions and aqueous extracts from fresh fruit and vegetables of different colors. The Im presented consistently accurate and precise results from colorless to colored model solutions and from fruit/vegetable extracts with standard deviation (Stdev) in the range of +-0.013 - +-0.405 and +-0.019 - +-0.428 respectively with no significant difference between the replicates. The Dm worked also satisfactorily for colorless model solutions and extracts (Stdev range +-0.235 - +-0.309) while producing unsatisfactory results (+-0.464 - +-3.281) for colored counterparts. Severe discrepancies/ overestimates continued to pileup (52% to 197%) estimating the nutrient from high (3.0 mg/10mL) to low (0.5 mg/10mL) concentration levels, respectively. On the basis of precision and reliability, the Im technique is suggested for adoption in general laboratories for routine estimation of ascorbic acid from fruit and vegetables possessing any shade. (author)

  6. Iodine application increased ascorbic acid content and modified the vascular tissue in opuntia ficus-indica

    International Nuclear Information System (INIS)

    The objective of this study was to discern the effect of applying both iodide and iodate to Opuntia ficus indica irrigation. The effect of iodate (KIO/sub 3/, 10-4 M) and iodide (KI, 10-4 M) on plant growth, yield and morphology was studied. Experiments were carried in three samples under tunnel conditions. In the last sampling, iodine species (KIO/sub 3/, KI) caused a negative effect in biomass. The amount of ascorbic acid, however, was increased over 51% in both iodine treatments. Phosphorus (0.26%), iron (50 ppm), and magnesium (1402 ppm) increases were also observed with iodate treatment in the first sampling, and increases in potassium (46.8 ppm) were apparent in the second. Iodide treatment increased the amounts of copper (1.02 ppm) and manganese (32.80 ppm) in the first sampling. Iodate treatment modified the number of xylem vessels and increased both the mucilage area and amount of druses. In general this study shows that iodate increases the amount of ascorbic acid and the morphology of the vascular tissue. (author)

  7. Ascorbic Acid Content in Extractive Aqueous Solutions of Rosa canina L. Fruits

    Directory of Open Access Journals (Sweden)

    Veturia-Ileana Nueleanu

    2008-03-01

    Full Text Available The main goal of the hereby study is two folded: first, to mark out the most adequate methods of preparing the watery solution extracts (infusions, decoctions in order to obtain a high content of ascorbic acid, and second, to identify the most suitable method for determining this vitamin in aqueous solution extracts made out of medicinal herbs. In this experiment six groups were assembled containing 20 fruit samples each. The samples were analyzed one week, one and a half month and three months, respectively, after gathering. Fruit drying was accomplished either in open air, at room temperature, or artificially, for three days, in 15 minutes intervals at 95°C (in the exicator, followed again by room temperature drying. Preparation of each group was different: it comprised either pickling in cold water for 10 hours, followed by sinking in cold water, boiling and then cooling, or sinking the fruits in boiling water followed by cooling, or sinking the fruits in boiling water followed by boiling the solution for five or 10 minutes, or, finally, by infusion and decoction method. The results obtained through the Tillmans method revealed a high level of ascorbic acid when the fruits were immersed into boiling water (100°C and boiled in open fire (11.02 ± 1.51 mg % for five minutes or when they were introduced in boiling water and kept covered in the boiling basin for 30 minutes (12.26 ± 0.55mg %.

  8. Corrosion behaviours of AISI 304 stainless steel and Inconel-600 in EDTA/citric acid/ascorbic acid base decontamination solution

    International Nuclear Information System (INIS)

    Corrosion behaviours of AISI 304 stainless steel (SS) and Inconel-600 in dilute EDTA/citric acid/ascorbic acid solution of pH = 2.8 have been studied at 95 .deg. C with electrochemical polarization, weight loss measurement and metallographic observation. Polarization curves on AISI 304 SS were very similar to those on Inconel-600 in all solutions except a slightly higher passive current density on Inconel-600. Anodic polarization curves on AISI 304 SS and Inconel-600 in EDTA/citric acid mixture were also similar to those in EDTA solution. A passive region was found over the range of potential from-300 mV to 400 mV in EDTA solution as well as in EDTA/citric acid mixture. The passive current density in EDTA solution and in EDTA/citric acid mixture dose not depend on both kinds and concentration of chemicals in the experimental range. In case of EDTA/ascorbic acid mixture, the anodic current density was exactly the same with that in EDTA/citric acid mixture at potential below 100 mV. The higher anodic current density in EDTA/ascorbic acid mixture than in EDTA/citric acid mixture, however, was observed at potential above 100 mV. The metal oxidation current density calculated from weight loss at 400 mV in EDTA/ascorbic acid mixture was almost equal to that in EDTA/citric acid mixture. And anodic oxidation of chemicals on Pt increased with a sequence of citric acid, EDTA and ascorbic acid. So the higher anodic current in EDTA/ascorbic acid mixture than in EDTA/citric acid mic acid mixture than in EDTA/citric acid mixture was due to ascorbic acid oxidation. Those results indicated that EDTA, citric acid and ascorbic acid have no influence on corrosion behaviours of AISI 304 SS and Inconel-600 in the passive region. In all solutions passive current density was about 3 ? 5 ? A/cm2, and corrosion current density was about 1 ? 5 ? A. No pitting and intergranular corrosion were observed over the range of potential from 300 mV to 400 mV

  9. Expression profiling of ascorbic acid-related genes during tomato fruit development and ripening and in response to stress conditions

    DEFF Research Database (Denmark)

    Ioannidi, Eugenia; Kalamaki, Mary S.

    2009-01-01

    L-Ascorbate (the reduced form of vitamin C) participates in diverse biological processes including pathogen defence mechanisms, and the modulation of plant growth and morphology, and also acts as an enzyme cofactor and redox status indicator. One of its chief biological functions is as an antioxidant. L-Ascorbate intake has been implicated in the prevention/alleviation of varied human ailments and diseases including cancer. To study the regulation of accumulation of this important nutraceutical in fruit, the expression of 24 tomato (Solanum lycopersicon) genes involved in the biosynthesis, oxidation, and recycling of L-ascorbate during the development and ripening of fruit have been characterized. Taken together with L-ascorbate abundance data, the results show distinct changes in the expression profiles for these genes, implicating them in nodal regulatory roles during the process of L-ascorbate accumulation in tomato fruit. The expression of these genes was further studied in the context of abiotic and post-harvest stress, including the effects of heat, cold, wounding, oxygen supply, and ethylene. Important aspects of the hypoxic and post-anoxic response in tomato fruit are discussed. The data suggest that L-galactose-1-phosphate phosphatase could play an important role in regulating ascorbic acid accumulation during tomato fruit development and ripening.

  10. Estimation of Thiamin and Ascorbic Acid Contents in Fresh and Dried Hibiscus sabdarriffa (Roselle) and Lactuca sativa (Tettuce)

    OpenAIRE

    Sarkiyayi, S.

    2010-01-01

    The utilization of locally available vegetables is limited due to lack of information and knowledgeon their nutritive values. The thiamin and ascorbic acid content of both fresh and dried leaves of Hibiscussahdarriffa and Lactuca sativa was investigated. The result revealed that the thiamin content of dried and freshHibiscus sabdarrjffa was 0.00194mg/g and 0.75mg/g respectively. The thiamin content of dried and freshLactuca sativa were 0.00139mg/g and 15.08mg/g respectively. The ascorbic acid...

  11. [Content of biologically active substances--selenium, flavonoids, ascorbic acid and chlorophyllin of Allium ursinum L and Allium victorialis L].

    Science.gov (United States)

    Golubkina, N A; Malankina, E L; Kosheleva, O V; Solov'eva, A I

    2010-01-01

    Accumulation of selenium, flavonoids, chlorophyll and vitamin C by Allium ursinum L. and Allium victorialis L. are studied. Allium victorialis L. is shown to accumulate twice more selenium and flavonoids compared to Allium ursinum L. Increase of insolation elevates the concentration of the element, flavonoids and ascorbic acid in plants. Selenium concentration in Allium victorialis L. after selenium fertilization is higher compared to Allium ursinum L. The results indicate the significance of Allium victorialis L. as a source of natural antioxidants: selenium, flavonoids and ascorbic acid. PMID:20369631

  12. Effect of different coagels of 6-O-ascorbic acid alkanoates on permeation of Ibuprofen through hairless mouse skin

    OpenAIRE

    Saino, Vero?nica; Chetoni, Patrizia; Palma, Santiago D.; Allemandi, Daniel A.

    2009-01-01

    The purpose of the present investigation was to evaluate 6-O-palmitoyl ascorbic acid (ASC16) and 6-O-lauril ascorbic acid (ASC12) for their capacity to promote permeation of Ibuprofen (IBU) through hairless mouse skin in vitro. The permeation of Arfen® (IBU 10% P/P, commercial product), IBU solution (0.85% P/P, pH 7.4, 66.7 mM phosphate buffer: Isopropyl alcohol; 80:20) and IBU (0.85% P/P) vehiculized in ASCn coagels (5% w/v) were measured and comparatively analyzed. Although IBU release fro...

  13. Glassy carbon electrodes modified with multiwalled carbon nanotubes for the determination of ascorbic acid by square-wave voltammetry

    OpenAIRE

    Sushil Kumar,; Victoria Vicente-Beckett

    2012-01-01

    Multiwalled carbon nanotubes were used to modify the surface of a glassy carbon electrode to enhance its electroactivity. Nafion served to immobilise the carbon nanotubes on the electrode surface. The modified electrode was used to develop an analytical method for the analysis of ascorbic acid (AA) by square-wave voltammetry (SWV). The oxidation of ascorbic acid at the modified glassy carbon electrode showed a peak potential at 315 mV, about 80 mV lower than that observed at the bare (unmodif...

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

    OpenAIRE

    Edem; Dosunmu, Christopher A.; Miranda I.; Bassey Francesca I.

    2009-01-01

    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) ...

  15. Potentiometric determination of L-ascorbic acid in pharmaceutical samples by FIA using a modified tubular electrode

    OpenAIRE

    Fernandes Julio Cesar B.; Rover Jr. Laércio; Kubota Lauro T.; Oliveira Neto Graciliano de

    2000-01-01

    A flow injection system using a tubular electrode based on the redox properties of copper (II) ions occluded in EVA membrane was developed for L-ascorbic acid determination. The poly-ethylene-co-vinyl acetate (EVA 40% m/m) matrix was doped with copper (II) ions and dispersed on the surface of a graphite/epoxy tubular electrode. The electrode showed a super-Nernstian response for L-ascorbic acid concentration between 10-3 and 10-1 mol L-1 with a detection limit of 8.5×10-4 mol L-1, when 0.1 m...

  16. Mesoporous silica-coated gold nanorods: towards sensitive colorimetric sensing of ascorbic acid via target-induced silver overcoating

    Science.gov (United States)

    Wang, Guoqing; Chen, Zhaopeng; Chen, Lingxin

    2011-04-01

    This article describes a nonaggregation-based colorimetric assay of ascorbic acid by tailoring the optical properties of mesoporous silica-coated gold nanorods (MS GNRs) via silver overcoating. The colorimetric measurement of ascorbic acid (AA) concentration strongly relies on the fact that the blue shift effect of localized surface plasmon resonance (LSPR) peak of MS GNRs is gradually enlarged with the increase of AA amount. The limit of detection is determined to be 49 nM, which is comparable to that of quantum dots (QDs)-based fluorimetric methods.

  17. Mechanistic determination using arrays of variable-sized channel microband electrodes: The oxidation of ascorbic acid in aqueous solution

    OpenAIRE

    Prieto, F.; Coles, Ba; Compton, Rg

    1998-01-01

    "Two-dimensional voltammetry" using arrays of variable-sized gold channel microband electrodes in combination with variable flow rate measurements together with independent gold rotating disk electrode (RDE) data is applied to characterize the oxidation mechanism of L-ascorbic acid (AH2) to dehydro-L-ascorbic acid in aqueous solutions. At pH 2.1 and very low mass transport conditions the reaction is consistent with a CECE mechanism, while at higher mass transport conditions an ECfastCE mechan...

  18. Determination of Ascorbic Acid Content of Some Fruit Juices and Wine by Voltammetry Performed at Pt and Carbon Paste Electrodes

    OpenAIRE

    Aurel Pisoschi; Aurelia Magdalena Pisoschi; Aneta Pop; Gheorghe Petre Negulescu

    2011-01-01

    A method was developed for assessing ascorbic acid concentration in fruit juices and wine by differential pulse voltammetry. The oxidation peak for ascorbic acid occurs at about 530 mV (versus SCE) on a Pt strip working electrode and at about 470 mV on a carbon paste working electrode. The influence of the operational parameters like the pulse amplitude and the pulse period on the analytical signal was investigated. The obtained calibration graph shows a linear dependence between the peak hei...

  19. 2-O-?-glucopytanosyl L-ascorbic acid reduced mutagenicity at HPRT locus of mouse splenocytes following BNCT

    International Nuclear Information System (INIS)

    In boron neutron capture therapy (BNCT), normal tissue surrounding the tumor cells sometimes take up boron compounds resulting in radiation-induced damage to normal tissue. We have previously reported the evidence for increased the mutagenicity of thermal neutron in the presence of boron. In addition, we described the biological radio-protective effects of the ascorbic acid for mutation induction following BNCT in vitro. Here, we investigated these radio-protective effects of ascorbic acid for mutation induction in mouse splenocytes on HPRT locus following a BNCT study in vivo. (author)

  20. Functionalization of conducting polymer with novel Co(II) complex: Electroanalysis of ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Swati [School of Materials Science and Technology, Institute of Technology, Banaras Hindu University, Varanasi 221005 (India); Prakash, Rajiv, E-mail: rajivprakash12@yahoo.com [School of Materials Science and Technology, Institute of Technology, Banaras Hindu University, Varanasi 221005 (India)

    2010-06-15

    We report for the first time the functionalization of a conducting polymer with a metal complex in order to develop a new type of catalytic material exhibiting better electronic communication through their delocalized {pi} electrons. The Co(II) complex having hydroxyl group as functional moiety is chemically coupled with carboxyl group of polyanthranilic acid which itself is a self doped conducting polymer. The covalent linkage between Co(II) and -OH group is confirmed using UV-vis, FT-IR and NMR spectroscopic techniques. The Co(II) complex functionalized polymer does exhibit excellent redox behavior and stability with mixed properties of Co(II) complex and {pi}-conjugated polymer. The material possesses potential benefits in sensors/biosensor applications and it is demonstrated for the electroanalysis of ascorbic acid at a level of nano molar concentration.

  1. Functionalization of conducting polymer with novel Co(II) complex: Electroanalysis of ascorbic acid

    International Nuclear Information System (INIS)

    We report for the first time the functionalization of a conducting polymer with a metal complex in order to develop a new type of catalytic material exhibiting better electronic communication through their delocalized ? electrons. The Co(II) complex having hydroxyl group as functional moiety is chemically coupled with carboxyl group of polyanthranilic acid which itself is a self doped conducting polymer. The covalent linkage between Co(II) and -OH group is confirmed using UV-vis, FT-IR and NMR spectroscopic techniques. The Co(II) complex functionalized polymer does exhibit excellent redox behavior and stability with mixed properties of Co(II) complex and ?-conjugated polymer. The material possesses potential benefits in sensors/biosensor applications and it is demonstrated for the electroanalysis of ascorbic acid at a level of nano molar concentration.

  2. Modified gold electrodes based on thiocytosine/guanine-gold nanoparticles for uric and ascorbic acid determination

    International Nuclear Information System (INIS)

    The present paper describes the preparation of new modified surfaces for electrodes based on guanine/thiocytosine and gold nanoparticles. The gold nanoparticles were analyzed by UV–vis spectroscopy and transmission electron microscopy (TEM) and it was found that they have diameters between 30 and 40 nm. The layers were characterized by specular reflectance infrared spectroscopy (FTIR-RAS) and by atomic force microscopy (AFM). The thickness of layers was found to be approximately 30 nm for TC layers and 300 nm for GU layers. Every layer was characterized as electrochemical sensor (by cyclic voltammetry) both for uric acid and ascorbic acid determinations, separately and in their mixture. The modified sensors have good calibration functions with good sensitivity (between 1.145 and 1.406 mA cm?2/decade), reproducibility (thiocytosine (AuTC) and goldguanine (AuGU) layers

  3. The use of L-ascorbic acid in speciation of arsenic compounds in drinking water

    Directory of Open Access Journals (Sweden)

    Marjanovi? Nikola J.

    2009-01-01

    Full Text Available Arsenic speciation, besides total arsenic content determination, is very important in analysis of water, foodstuffs, and environmental samples, because of varying degrees of toxicity of different species. For such purpose hydride generation atomic absorption spectrometry can be used based on the generation of certain types of hydride, depending on the pH value and pretreatment in different reaction media. In this study, we have investigated the effect of L-ascorbic acid as the reaction medium as well as the pre-reducing agent in speciation of arsenic by hydride generation-atomic absorption spectrometry in order to determine monomethyl arsonic acid (MMA in the presence of inorganic forms of arsenic.

  4. Corrosion behaviours of AISI 304 stainless steel and Inconel-600 in EDTA/citric acid/ascorbic acid base decontamination solution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Pyo; Park, Sang Yoon; Oh, Won Zin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    1991-07-01

    Corrosion behaviours of AISI 304 stainless steel (SS) and Inconel-600 in dilute EDTA/citric acid/ascorbic acid solution of pH = 2.8 have been studied at 95 .deg. C with electrochemical polarization, weight loss measurement and metallographic observation. Polarization curves on AISI 304 SS were very similar to those on Inconel-600 in all solutions except a slightly higher passive current density on Inconel-600. Anodic polarization curves on AISI 304 SS and Inconel-600 in EDTA/citric acid mixture were also similar to those in EDTA solution. A passive region was found over the range of potential from-300 mV to 400 mV in EDTA solution as well as in EDTA/citric acid mixture. The passive current density in EDTA solution and in EDTA/citric acid mixture dose not depend on both kinds and concentration of chemicals in the experimental range. In case of EDTA/ascorbic acid mixture, the anodic current density was exactly the same with that in EDTA/citric acid mixture at potential below 100 mV. The higher anodic current density in EDTA/ascorbic acid mixture than in EDTA/citric acid mixture, however, was observed at potential above 100 mV. The metal oxidation current density calculated from weight loss at 400 mV in EDTA/ascorbic acid mixture was almost equal to that in EDTA/citric acid mixture. And anodic oxidation of chemicals on Pt increased with a sequence of citric acid, EDTA and ascorbic acid. So the higher anodic current in EDTA/ascorbic acid mixture than in EDTA/citric acid mixture was due to ascorbic acid oxidation. Those results indicated that EDTA, citric acid and ascorbic acid have no influence on corrosion behaviours of AISI 304 SS and Inconel-600 in the passive region. In all solutions passive current density was about 3 {approx} 5 {mu} A/cm{sup 2}, and corrosion current density was about 1 {approx} 5 {mu} A. No pitting and intergranular corrosion were observed over the range of potential from 300 mV to 400 mV.

  5. L-ascorbic acid quenching of singlet delta molecular oxygen in aqueous media: generalized antioxidant property of vitamin C

    International Nuclear Information System (INIS)

    L-ascorbic acid quenches singlet (1?/sub g/) molecular oxygen in aqueous media (pH 6.8 for [1H]H2O and pD 7.2 for (2H)D2O) as measured directly by monitoring (0,0) 1?/sub g/ ? 3?/sub g/- emission at 1.28 micron. Singlet oxygen was generated at room temperature in the solutions via photosensitization of sodium chrysene sulfonate; this sulfonated polycyclic hydrocarbon was synthesized to provide a water soluble chromophore inert to usual dye-ascorbate photobleaching. A marked isotope effect is found; k/sub Q//sup H2O/ is 3.3 times faster than k/sub Q//sup D2O/, suggesting ascorbic acid is chemically quenching singlet oxygen

  6. Measurement of cardiac output in adult and newborn animals by ascorbic acid dilution.

    Science.gov (United States)

    Smallwood, J K; Haselby, K A; Paradise, R R

    1984-05-01

    We have developed an ascorbic acid-dilution method for measuring cardiac output which requires minimal blood withdrawal. Ascorbate is injected into a central venous catheter. The indicator-dilution curve is obtained by drawing blood from an arterial catheter through an amperometric cell at 0.96 ml/min for 35 s. The current is measured by a picoammeter . A calibration curve is obtained in 15 s prior to each indicator-dilution curve. An on-line digital computer measures the curve areas and calculates the cardiac output. Cardiac outputs of heparinized dogs anesthetized with pentobarbital and halothane measured by this method (AA) compared closely to cardiac outputs measured by the dye-dilution method (CG) (AA = 0.96 CG + 20 ml/min, r = 0.98). Both the cardiac output and the arterial blood pressure remained stable during replicate measurements of the cardiac output of 1-day-old piglets. This system allows cardiac output determinations of neonatal subjects without excessive blood removal and, with further development, should be practical in human neonates. PMID:6372525

  7. Serum Angiotensin Converting Enzyme Activity, Total Antioxidants and Ascorbic Acid in Iranian Patients with Coronary Artery Disease

    Directory of Open Access Journals (Sweden)

    F. Ghazi

    2009-01-01

    Full Text Available Angiotensin-Converting Enzyme (ACE is a dipeptidyl carboxypeptidase (EC: 3.4.15.1 that catalyzes the conversion of angiotensin I to the potent vasoconstrictor angiotensin II. Angiotesin II is responsible for an increase in blood pressure and maintenance of hypertension through the stimulation of oxidative stress. The relationship between Coronary Artery Disease (CAD, Angiotensin-Converting Enzyme (ACE activity, ascorbic acid and serum antioxidant status in patients with coronary artery disease. A group of 65 patients with angiographically defined Coronary Artery Disease (CAD and 60 normal control subjects were examined. The activity of Angiotensin-Converting Enzyme (ACE was determined by the reversed-phase High Performance Liquid Chromatography (HPLC to separate and quantify Hippuryl-Histidyl-Leucin (HHL and Hippuric Acid (HA. Ferric Reducing Ability of Plasma (FRAP Assay as a measure of antioxidant power was used. Serum ascorbic acid concentration was determined photometrically. The results demonstrated significant differences in ACE activity, antioxidant and ascorbic acid between CAD cases and normal controls. Increased levels of ACE activity in serum have been related to coronary artery disease. Serum ascorbic acid concentration (25.6±3.8 mg dL-1 and total antioxidant capacity (475.5±18.51 ?M L-1 were significantly (p<0.05 decreased in CAD patients compared with controls.

  8. Determination of Ascorbic Acid Content of Some Fruit Juices and Wine by Voltammetry Performed at Pt and Carbon Paste Electrodes

    Directory of Open Access Journals (Sweden)

    Aurel Pisoschi

    2011-02-01

    Full Text Available A method was developed for assessing ascorbic acid concentration in fruit juices and wine by differential pulse voltammetry. The oxidation peak for ascorbic acid occurs at about 530 mV (versus SCE on a Pt strip working electrode and at about 470 mV on a carbon paste working electrode. The influence of the operational parameters like the pulse amplitude and the pulse period on the analytical signal was investigated. The obtained calibration graph shows a linear dependence between the peak height and ascorbic acid concentration within the range 0.31-20 mM with a Pt working electrode, and within the range 0.07-20 mM with a carbon paste working electrode. The equation of the calibration graph was y = 21.839x + 35.726, r2 = 0.9940, when a Pt strip electrode was used (where y represents the value of the current intensity measured for the peak height, expressed as µA and x the analyte concentration, as mM. R.S.D. = 2.09%, n = 10, Cascorbic acid = 2.5 mM. The equation of the calibration graph was y = 3.4429x + 5.7334, r2 = 0.9971, when a carbon paste electrode was used (where y represents the value of intensity measured for the peak height, expressed as µA and x the analyte concentration, as mM. R.S.D. = 2.35%, n = 10, Cascorbic acid = 2.5 mM. The developed method was applied to ascorbic acid assessment in fruit juices and wine. The ascorbic acid content determined ranged between 6.83 mg/100 mL juice for soft drinks (Fanta Madness and 54.74 mg/100 mL for citrus (lemon juices obtained by squeezing fruit. Different ascorbic acid concentrations (from standard solutions were added to the analysed samples, the degree of recovery being comprised between 94.74 and 104.97%. The results of ascorbic acid assessment by differential pulse voltammetry were compared with those obtained by cyclic voltammetry. The results obtained by the two methods were in good agreement.

  9. Dietary ascorbic acid and subsequent change in body weight and waist circumference : associations may depend on genetic predisposition to obesity--a prospective study of three independent cohorts

    DEFF Research Database (Denmark)

    Larsen, Sofus C; Angquist, Lars

    2014-01-01

    BACKGROUND: Cross-sectional data suggests that a low level of plasma ascorbic acid positively associates with both Body Mass Index (BMI) and Waist Circumference (WC). This leads to questions about a possible relationship between dietary intake of ascorbic acid and subsequent changes in anthropometry, and whether such associations may depend on genetic predisposition to obesity. Hence, we examined whether dietary ascorbic acid, possibly in interaction with the genetic predisposition to a high BMI, WC or waist-hip ratio adjusted for BMI (WHR), associates with subsequent annual changes in weight (?BW) and waist circumference (?WC). METHODS: A total of 7,569 participants' from MONICA, the Diet Cancer and Health study and the INTER99 study were included in the study. We combined 50 obesity associated single nucleotide polymorphisms (SNPs) in four genetic scores: a score of all SNPs and a score for each of the traits (BMI, WC and WHR) with which the SNPs associate. Linear regression was used to examine the association between ascorbic acid intake and ?BW or ?WC. SNP-score?×?ascorbic acid interactions were examined by adding product terms to the models. RESULTS: We found no significant associations between dietary ascorbic acid and ?BW or ?WC. Regarding SNP-score?×?ascorbic acid interactions, each additional risk allele of the 14 WHR associated SNPs associated with a ?WC of 0.039?cm/year (P?=?0.02, 95% CI: 0.005 to 0.073) per 100?mg/day higher ascorbic acid intake. However, the association to ?WC only remained borderline significant after adjustment for ?BW. CONCLUSION: In general, our study does not support an association between dietary ascorbic acid and ?BW or ?WC, but a diet with a high content of ascorbic acid may be weakly associated to higher WC gain among people who are genetically predisposed to a high WHR. However, given the quite limited association any public health relevance is questionable.

  10. Dietary ascorbic acid and subsequent change in body weight and waist circumference : associations may depend on genetic predisposition to obesity - a prospective study of three independent cohorts

    DEFF Research Database (Denmark)

    Larsen, Sofus C; Angquist, Lars

    2014-01-01

    BACKGROUND: Cross-sectional data suggests that a low level of plasma ascorbic acid positively associates with both Body Mass Index (BMI) and Waist Circumference (WC). This leads to questions about a possible relationship between dietary intake of ascorbic acid and subsequent changes in anthropometry, and whether such associations may depend on genetic predisposition to obesity. Hence, we examined whether dietary ascorbic acid, possibly in interaction with the genetic predisposition to a high BMI, WC or waist-hip ratio adjusted for BMI (WHR), associates with subsequent annual changes in weight (?BW) and waist circumference (?WC). METHODS: A total of 7,569 participants' from MONICA, the Diet Cancer and Health study and the INTER99 study were included in the study. We combined 50 obesity associated single nucleotide polymorphisms (SNPs) in four genetic scores: a score of all SNPs and a score for each of the traits (BMI, WC and WHR) with which the SNPs associate. Linear regression was used to examine the association between ascorbic acid intake and ?BW or ?WC. SNP-score?×?ascorbic acid interactions were examined by adding product terms to the models. RESULTS: We found no significant associations between dietary ascorbic acid and ?BW or ?WC. Regarding SNP-score?×?ascorbic acid interactions, each additional risk allele of the 14 WHR associated SNPs associated with a ?WC of 0.039?cm/year (P?=?0.02, 95% CI: 0.005 to 0.073) per 100?mg/day higher ascorbic acid intake. However, the association to ?WC only remained borderline significant after adjustment for ?BW. CONCLUSION: In general, our study does not support an association between dietary ascorbic acid and ?BW or ?WC, but a diet with a high content of ascorbic acid may be weakly associated to higher WC gain among people who are genetically predisposed to a high WHR. However, given the quite limited association any public health relevance is questionable.

  11. Marked increase in urinary excretion of nitrate and N-nitrosothioproline in the osteogenic disordered syndrome rats, lacking ascorbic acid biosynthesis, by administration of lipopolysaccharide and thioproline.

    Science.gov (United States)

    Tsuda, M; Kurashima, Y; Kosaka, H; Ohshima, H; Sugimura, T; Esumi, H

    1995-11-01

    Urinary excretions of nitrate and N-nitrosothiazolidine-4-carboxylic acid (N-nitrosothioproline; NTPRO) were determined in rats with osteogenic disordered syndrome (ODS, od/od), lacking L-ascorbic acid (ASC) biosynthesis, after i.p. administration of Escherichia coli lipopolysaccharide (LPS, 1 mg/kg) followed by thiazolidine-4-carboxylic acid (thioproline, 20 mg/rat). L-Ascorbic acid-sufficient ODS rats showed the excretion of nitrate and NTPRO at the levels of 20.3 +/- 7.9 mumol/24h and 369 +/- 111 pmol/24 h respectively, whereas the levels of nitrate and NTPRO in ASC-deficient (scorbutic) rats increased to 54.7 +/- 5.6 mumol/24 h (P < 0.01) and 796 +/- 367 pmol/24 h (P < 0.05) respectively. Administration of L-arginine further increased urinary excretion of nitrate and NTPRO while D-arginine showed no effect. NG-Monomethyl-L-arginine, a specific inhibitor of nitric oxide synthase (NOS), strongly inhibited endogenous formation of both nitrate and NTPRO. These results indicate that increased excretion of NTPRO in ODS rats stimulated by LPS involves induction of NOS leading to an increase in endogenous formation of reactive nitrogen oxides such as N2O3, a potent nitrosating agent at physiological pH conditions. Increased NOS activities in the plasma and various tissues of ODS rats were observed 5 h after treatment with LPS. The possibility of extragastric N-nitroso compound formation in inflammation sites is discussed. PMID:7586182

  12. Simultaneous determination of norepinephrine, uric acid, and ascorbic acid at a screen printed carbon electrode modified with polyacrylic acid-coated multi-wall carbon nanotubes.

    Science.gov (United States)

    Huang, Shih-Hung; Liao, Hsiu-Hsien; Chen, Dong-Hwang

    2010-06-15

    A screen printed carbon electrode (SPCE) modified with polyacrylic acid-coated multi-wall carbon nanotubes (PAA-MWCNTs) has been prepared by the dispersion of MWCNTs in PAA aqueous solution via sonication and the followed drop-coating for the simultaneous determination of norepinephrine (NE), uric acid (UA), and ascorbic acid (AA). The presence of PAA inhibited the adsorption of AA owing to the electrostatic repulsion, but was favorable for the affinity adsorption of NE and UA via the ion exchange and hydrogen bonding mechanisms, respectively. This led to the decrease in the oxidation potential of AA and the significantly enhanced oxidation peak currents of NE and UA at the PAA-MWCNTs/SPCE. By cyclic voltammetry and differential pulse voltammetry, the oxidation potentials of NE, UA, and AA at the PAA-MWCNTs/SPCE in a ternary mixture were found to be well resolved so that their simultaneous determination could be achieved. Furthermore, the interaction of NE, UA, and AA with PAA accounted for their electrochemical responses at different pH values. Also, the effect of pH revealed that the oxidation of NE, UA, and AA at the PAA-MWCNTs/SPCE all involved the transfer of two electrons. In addition, by differential pulse voltammetry, the linear dependence of peak current on the concentration was obtained in the ranges of 0-10, 0-30, and 100-1000 microM with the lowest detection limits of 0.131, 0.458, and 49.8 microM for NE, UA, and AA, respectively. PMID:20395124

  13. A sensor of a polyoxometalate and Au–Pd alloy for simultaneously detection of dopamine and ascorbic acid

    International Nuclear Information System (INIS)

    A composite film based on K8P2W16V2O62·18H2O decorated by Au–Pd nanoparticles was prepared by the layer-by-layer self-assembly method. This composite film exhibits enhanced electrocatalytic performance, repeatability and long-term stability for the simultaneous determination of dopamine and ascorbic acid at biological pH (pH 7.0). The proposed electrochemical sensing film for simultaneous detecting dopamine and ascorbic acid shows rather low detection limit of 8.3 × 10?7 and 4.3 × 10?7 M and a linear response range from 2.1 × 10?6 to 2.06 × 10?3 M and 1.2 × 10?6 to 1.61 × 10?3 M, as well as no interference from the common interfering species at an applied potential. -- Abstract: A novel composite film based on Dawson-type phosphovanadotungstate K8P2W16V2O62·18H2O (P2W16V2) decorated by Au–Pd alloy nanoparticles (Au–Pd) was fabricated on quartz, silicon and ITO using the layer-by-layer self-assembly method. The composite film was characterized by UV–vis spectroscopy, X-ray photoelectron spectra, atomic force microscopy, Scanning electronic microscope, cyclic voltammetry and differential pulse voltammetry. The composite film can be employed for sensitive and simultaneous determination of dopamine and ascorbic acid at biological pH (pH 7.0). Linear analytical curves were obtained in the ranges from 2.1 × 10?6 to 2.06 × 10?3 M and 1.2 × 10?6 to 1.61 × 10?3 M for dopamine and ascorbic acid by DPV methods, respectively. The low detection limit for dopamine and ascorbic acid were 8.3 × 10?7 and 4.3 × 10?7 M, as well as no interference was observed from the common interfering species such as glucose, uric acid, L-cysteine, CH3OH, CH3CH2OH and H2O2. The composite film was used for dopamine and ascorbic acid determinations in real samples with satisfactory results. With high sensitivity and selectivity, the proposed electrochemical sensor would provide a simple method for simultaneous determination of dopamine and ascorbic acid in practical applications

  14. Biosynthesis of l-Ascorbic Acid and Conversion of Carbons 1 and 2 of l-Ascorbic Acid to Oxalic Acid Occurs within Individual Calcium Oxalate Crystal Idioblasts1

    Science.gov (United States)

    Kostman, Todd A.; Tarlyn, Nathan M.; Loewus, Frank A.; Franceschi, Vincent R.

    2001-01-01

    l-Ascorbic acid (AsA) and its metabolic precursors give rise to oxalic acid (OxA) found in calcium oxalate crystals in specialized crystal idioblast cells in plants; however, it is not known if AsA and OxA are synthesized within the crystal idioblast cell or transported in from surrounding mesophyll cells. Isolated developing crystal idioblasts from Pistia stratiotes were used to study the pathway of OxA biosynthesis and to determine if idioblasts contain the entire path and are essentially independent in OxA synthesis. Idioblasts were supplied with various 14C-labeled compounds and examined by micro-autoradiography for incorporation of 14C into calcium oxalate crystals. [14C]OxA gave heavy labeling of crystals, indicating the isolated idioblasts are functional in crystal formation. Incubation with [1-14C]AsA also gave heavy labeling of crystals, whereas [6-14C]AsA gave no labeling. Labeled precursors of AsA (l-[1-14C]galactose; d-[1-14C]mannose) also resulted in crystal labeling, as did the ascorbic acid analog, d-[1-14C]erythorbic acid. Intensity of labeling of isolated idioblasts followed the pattern OxA > AsA (erythorbic acid) > l-galactose > d-mannose. Our results demonstrate that P. stratiotes crystal idioblasts synthesize the OxA used for crystal formation, the OxA is derived from the number 1 and 2 carbons of AsA, and the proposed pathway of ascorbic acid synthesis via d-mannose and l-galactose is operational in individual P. stratiotes crystal idioblasts. These results are discussed with respect to fine control of calcium oxalate precipitation and the concept of crystal idioblasts as independent physiological compartments. PMID:11161021

  15. Comparative study of the efficacy of ascorbic acid, quercetin, and thiamine for reversing ethanol-induced toxicity.

    Science.gov (United States)

    Ambadath, Vidhya; Venu, Renju Gopal; Madambath, Indira

    2010-12-01

    This study compares the curative effect of three antioxidants-ascorbic acid, quercetin, and thiamine-on ethanol-induced toxicity in rats. Administration of ethanol at a dose of 4 g/kg of body weight/day for 90 days initiated chronic alcohol-induced oxidative stress as shown by increased malondialdehyde level and DNA fragmentation in liver and brain. Ethanol administration also led to a decrease in DNA content. Activities of toxicity marker enzymes-alanine aminotransferase, aspartate aminotransferase, and ?-glutamyltranspeptidase-in liver and serum increased progressively upon ethanol administration. After ethanol administration for 90 days, the efficacy of antioxidant treatment of the alcohol-induced toxicity was studied by supplementing ascorbic acid (200 mg/100 g of body weight/day), quercetin (50 mg/kg of body weight/day), and thiamine (25 mg/kg of body weight/day) for 30 days. These groups were compared with the abstention group (not treated with ethanol). All the alterations induced by alcohol were reduced significantly by the supplementation of antioxidants and also with abstention. The regression by antioxidants was greater that of abstention. Antioxidants significantly reduced the oxidative stress induced by ethanol intoxication, increased membrane integrity, and also increased organ regeneration. Ascorbic acid was shown to be more effective than quercetin and thiamine in treating both hepatotoxicity and neurotoxicity induced by alcohol administration. This may be due to the higher antioxidant potential of ascorbic acid in physiological conditions. PMID:20946019

  16. Identification and thermal degradation kinetics of chlorophyll pigments and ascorbic acid from ditax nectar (Detarium senegalense J.F. Gmel).

    Science.gov (United States)

    Diop Ndiaye, Nafissatou; Dhuique-Mayer, Claudie; Cisse, Mady; Dornier, Manuel

    2011-11-23

    Detarium senegalense J.F. Gmel (ditax) is a forest tree found in Senegal the fruits of which are characterized by an attractive green flesh with a high amount in ascorbic acid. It is generally consumed as a nectar in Senegal. In this study, the main pigments of ditax pulp were identified and quantified by HPLC-DAD. Pheophytin a (128 mg/kg), which represents 58% of the total pigments, followed by hydroxypheophytin a' (33 mg/kg), chlorophyll b (24 mg/kg), and chlorophyll a (20 mg/kg) was the major pigment of ditax pulp. Lutein and ?-carotene were present in lower amounts (4.6 and 3.6 mg/kg, respectively). The thermal degradation kinetics of pheophytin a, hydroxypheophytin a', and ascorbic acid were determined at temperatures ranging from 60 to 95 °C in ditax nectar. Pheophytin a was the most heat sensitive. Thermal processing induced the formation of degradation products such as pyropheophytin a and pyropheophytin b. The kinetics parameters have been calculated according to the models of Arrhenius, Eyring, and Ball. Following the Arrhenius relation, activation energies of pheophytin a, hydroxypheophytin a', and ascorbic acid were, respectively, 79, 74, and 46 kJ mol(-1). Losses calculated during isothermal treatments were close to experimental losses in pheophytin a, hydroxypheophytin a', and ascorbic acid. The Eyring model can then be used to predict chlorophyll pigments and vitamin C losses during pasteurization of the nectar (<10%). PMID:21981680

  17. A GREEN CHEMISTRY APPROACH TO PREPARATION OF CORE (FE OR CU)-SHELL (NOBLE METALS) NANOCOMPOSITES USING AQUEOUS ASCORBIC ACID

    Science.gov (United States)

    A greener method to fabricate novel core (Fe or Cu)-shell (noble metals) nanocomposites of transition metals such as Fe and Cu and noble metals such as Au, Pt, Pd, and Ag using aqueous ascorbic acid is described. Transition metal salts such as Cu and Fe were reduced using ascor...

  18. EFFECTS OF DEPLETION OF ASCORBIC ACID OR NONPROTEIN SULFYDRYLS ON THE ACUTE INHALATION TOXICITY OF NITROGEN DIOXIDE, OZONE, AND PHOSGENE

    Science.gov (United States)

    The effect of depleting lung ascorbic acid (AH2) and nonprotein sulfhydryls (NPSH) on the acute inhalation toxicity of nitrogen dioxide (N02), ozone (03), and phosgene (C0Cl2) was investigated in guinea pigs. he increase in bronchoalveolar lavage (BAL) fluid protein (an indicator...

  19. Effect of ascorbic acid on long-term cold exposure induced changes in thyroid activity in sprague dawley rats

    International Nuclear Information System (INIS)

    Objective: To determine the effect of ascorbic acid supplementation on long-term cold exposure induced changes in thyroid activity in Sprague-Dawley rats. Study Design: Experimental study. Place and Duration of Study: Physiology Department of Islamic International Medical College, Rawalpindi, National Institute of Health, Islamabad and Railway Hospital, Rawalpindi, from January to December 2009. Methodology: Ninety Sprague-Dawley rats were randomly divided into three groups of control, cold exposed and cold exposed along with ascorbic acid supplementation. After one month, their thyroid levels were analyzed by using chemiluminescent immunometric Assay on Siemens Immulite 2000 Analyzer. Results: After 4 weeks of cold exposure to experimental animals, the thyroid activity was raised significantly in the cold exposed group as compared to the control group (p-value for T3 difference = 0.004, T4 difference = 0.002 and TSH difference < 0.001). Supplementation with ascorbic acid in the third group normalized the thyroid hormone activity with p-value for difference in levels of T3 being 0.6661, T4 = 0.027 and TSH = 0.0028. Conclusion: Ascorbic acid prevented the cold induced changes in thyroid hormone levels in rodents. (author)

  20. Effects of Ascorbic Acid on Egg Production and Egg Shell Quality in Laying Hens Drinking Saline Water

    Directory of Open Access Journals (Sweden)

    J. Mirabdollbaghi

    2006-01-01

    Full Text Available An experiment was conducted to study the effects of different water source, saline water (Tap water +2 g L-1 Na and tape water with a diet that supplemented by three level of Ascorbic Acid (0, 1.5 and 3 g kg-1 of diet on laying hen`s performance and egg shell quality. This trail was carried out on 108 commercial laying hens (Hy-Line 32 weeks old for 12 weeks. All of the data were subjected to Two- way analysis of variance test. The result showed that egg production (%, egg weight (g, egg mass (g/h/day, feed conversion ratio, feed consumptions didn`t effected by saline water but using saline water increased the percentage of eggs with damaged shells (p<0.01. Also the effect of different level of Ascorbic acid on egg production (%, egg weight (g, egg mass (g/h/day, feed conversion ratio were not significant, but feed consumption reduced by using ascorbic acid (p<0.05. Egg shell thickness (mm, egg shell weight (%, egg shell weight (mg/cm2, egg specific gravity, egg shell calcium (% and egg shell phosphorous (% didn`t affected by saline water and different level of Ascorbic acid.

  1. A self-seeding synthesis of Ag microrods of tuned aspect ratio: ascorbic acid plays a key role

    Science.gov (United States)

    Visaveliya, Nikunjkumar; Köhler, J. Michael

    2013-08-01

    Control of the shape and size of nanoparticles is crucial for using them as labels or as building blocks in nanotechnology. In fact, silver has so far been considered as having the widest variety of different morphologies at the nano-scale and micro-scale levels. To make progress in these criteria, in our paper we have synthesized highly reproducible silver (Ag) microrods of controlled aspect ratios through a rapid self-seeding method. The Ag nano seeds are formed via the reduction of Ag ions in hot ethylene glycol by ascorbic acid, and the subsequent growth of microrods is controlled by further deposition of Ag atoms in the presence of poly(vinylpyrrolidone). Moreover, ascorbic acid is exclusively responsible for the rod morphology, as we describe here in detail. A very low concentration of ascorbic acid forms very few Ag microrods along with a majority of Ag colloidal particles, while random overgrowth on the surfaces is observed for higher concentrations. The critical reaction condition has been found in that the aspect ratio of the Ag microrods can be systematically tuned between 4 and 90. Also, the method in which ascorbic acid is added to the reaction medium plays a key role in controlling the aspect ratio of the Ag microrods. The non-monotonic dependence of the length and the diameter of the Ag microrods has been described by an empirical equation. The function can be interpreted by means of concentration-dependent competition between the adsorption of ligands and metal deposition.

  2. Simultaneous voltammetric detection of ascorbic acid, dopamine and uric acid using a pyrolytic graphite electrode modified into dopamine solution.

    Science.gov (United States)

    da Silva, Robson P; Lima, Antonio William O; Serrano, Silvia H P

    2008-03-31

    Pyrolytic graphite electrodes (PGE) were modified into dopamine solutions using phosphate buffer solutions, pH 10 and 6.5, as supporting electrolyte. The modification process involved a previous anodization of the working electrode at +1.5 V into 0.1 mol L(-1) NaOH followed by other anodization step, in the same experimental conditions, into dopamine (DA) solutions. pH of the supporting electrolyte performed an important role in the production of a superficial melanin polymeric film, which permitted the simultaneous detection of ascorbic acid (AA), (DA) and uric acid (UA), DeltaE(AA-DA)=222 mV; DeltaE(AA-UA)=360 mV and DeltaE(DA-UA)=138 mV, avoiding the superficial poisoning effects. The calculated detection limits were: 1.4x10(-6) mol L(-1) for uric acid, 1.3x10(-5)molL(-1) for ascorbic acid and 1.1x10(-7) mol L(-1) for dopamine, with sensitivities of (7.7+/-0.5), (0.061+/-0.001) and (9.5+/-0.05) A mol(-1) cm(-2), respectively, with no mutual interference. Uric acid was determined in urine, blood and serum human samples after dilution in phosphate buffer and no additional sample pre-treatment was necessary. The concentration of uric acid in urine was higher than the values found in blood and serum and the recovery tests (92-102%) indicated that no matrix effects were observed. PMID:18331862

  3. Rapid screening of ascorbic acid, glycoalkaloids, and phenolics in potato using high-performance liquid chromatography.

    Science.gov (United States)

    Shakya, Roshani; Navarre, Duroy A

    2006-07-26

    Evaluation of phenolic metabolism in potato tubers (Solanum tuberosum) would be facilitated by faster analytical methods. A high-throughput HPLC method was developed for the qualitative and quantitative determination in potato of numerous phenolic compounds, the sum of the glycoalkaloids chaconine and solanine, plus ascorbic acid. Following a fast extraction, HPLC run times of 12 min were achieved with the use of a monolithic RP C18 column. UV and MS analyses were used to characterize the phenolic complement in extracts from two white-fleshed varieties. Over 30 compounds were identified, some of which are thought to possess either nutritional value or are involved in plant disease resistance. This method is expected to be useful for germplasm mining and for varietal development programs in which large numbers of lines are generated. PMID:16848503

  4. Polyoxometalate-Graphene Nanocomposite Modified Electrode for Electrocatalytic Detection of Ascorbic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Weiying; Du, Dan; Gunaratne, Kalupathirannehelage Don D.; Colby, Robert J.; Lin, Yuehe; Laskin, Julia

    2014-01-15

    Phosphomolybdate functionalized graphene nanocomposite (PMo12-GS) has been successfully formed on a glassy carbon electrode (GCE) for the detection of ascorbic acid (AA). The obtained PMo12-GS modified GCE, was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy and compared with GCE, GS modified GCE, and PMo12 modified GCE. It shows an increased current and a decrease in over-potential of ~210 mV. The amperometric signals are linearly proportional to the AA concentration in a wide concentration range from 1×10?6 M to 8×10?3 M, with a detection limit of 0.5×10?6 M. The PMo12-GS modified electrode was employed for the determination of the AA level in vitamin C tablets, with recoveries between 96.3 and 100.8?%.

  5. Direct fluorimetric determination of ascorbic acid by the supramolecular system of AA with ?-cyclodextrin derivative

    Science.gov (United States)

    Wang, Lun; Zhang, Li; She, Shike; Gao, Feng

    2005-09-01

    We established a simple and selective fluorimetric method for the determination of ascorbic acid (AA) with the novel mono-[6- N(4-carboxy-phenyl)]-?-cyclodextrin (ACD). The method is based on the fluorescence intensity of ACD decreases as the ACD-AA supramolecular complexes form. The fluorescence intensity is measured at excitation and emission wavelengths of 270 and 352 nm, respectively. Under optimum condition, a linear relationship is obtained between the fluorescence intensity and the concentration of AA in the range of 0.05-8.0 ?g ml -1. The detection limit is 0.012 ?g ml -1. The method has been applied to the direct analysis of AA in real samples with satisfactory results.

  6. A direct comparison of nanosilver particles and nanosilver plates for the oxidation of ascorbic acid

    Science.gov (United States)

    Sadeghi, Babak; Meskinfam, Masoumeh

    2012-11-01

    We study of spherical silver nanoparticles of different size and Ag nanoplates were grown at zinc tin oxide (ZTO) surface and characterized using SEM. The application of different electrodes in voltammetry for determination ascorbic acid indicated that oxidation of this biomolecule occurs at these electrodes in diffusion controlled process. Ag nanoplates modified zinc tin oxide electrodes exhibit at least two to three times higher current than spherical nanosilver particles. The observed behavior suggests that Ag nanoplates exhibit higher electrocatalytic activity than spherical silver nanoparticles. The reason for such behavior may be due to lattice plane as well as due to more available surface edges. As dimensions of nanoplates are increased surface area in the case of nanoplates also appears to play a significant role.

  7. Photometric starch-iodine determination in plant materials as influenced by ascorbic acid. Critical remarks

    Directory of Open Access Journals (Sweden)

    Bogus?aw Samotus

    1994-03-01

    Full Text Available Following the work of Sharma et al. (1990 on the interference of ascorbic acid (AA with starch-iodine reaction, the present authors repeated it, giving a proper explanation of the influence of AA in this reaction. AA oxidizes iodine-iodide (I-KI reagent which makes impossible to form the blue complex with starch. Three measures are suggested to overcome the interference of AA: 1 to titrate starch solution with I-KI reagent and thus work out an I-KI amount for development of blue coloration, 2 to remove from plant material AA (and other reducing soluble substances by washing the material with cold water or ethanol, and 3 starch solution could be treated with alkali (pH about 9, which destroys AA in 15 minutes. After acidifying the solution and adding I-KI reagent the blue complex can be determined.

  8. Dielectric behaviour and intermolecular association between L(+) ascorbic acid and ethanol

    International Nuclear Information System (INIS)

    In order to determine the dipole moment of L(+) ascorbic acid and the relation to its structure the experimental variations of permitivities, refractive indices and specific volumes of a series of dilute ethanolic solutions at 25 deg C were examined. The average moment (?) using Buckingham equation was found to be 5,58 D considering the spherical approximation and 7,81 D if the ellipsoidal form factor was considered. The calculated ? value through vectorial addition was 4,98 D. The solute partial molal volume in the studied range was calculated to be 94,73 cm3 instead of the theoretical value of 106,71 cm3. Both discrepancies are attributed to intermolecular solute-solvent interactions. A possible electronic displacement which favours hydrogen bonding with the solvent is postulated. (Author)

  9. Sensitive and reliable ascorbic acid sensing by lanthanum oxide/reduced graphene oxide nanocomposite.

    Science.gov (United States)

    Mogha, Navin Kumar; Sahu, Vikrant; Sharma, Meenakshi; Sharma, Raj Kishore; Masram, Dhanraj T

    2014-10-01

    A simple strategy for the detection and estimation of ascorbic acid (AA), using lanthanum oxide-reduced graphene oxide nanocomposite (LO/RGO) on indium tin oxide (ITO) substrate, is reported. LO/RGO displays high catalytic activity toward the oxidation of AA, and the synergism between lanthanum oxide and reduced graphene oxide was attributed to the successful and efficient detection. Detection mechanism and sensing efficacy of LO/RGO nanocomposite are investigated by electrochemical techniques. Chronoamperometric results under optimal conditions show a linear response range from 14 to 100 ?M for AA detection. Commercially available vitamin C tablets were also analyzed using the proposed LO/RGO sensor, and the remarkable recovery percentage (97.64-99.7) shows the potential application in AA detection. PMID:24879601

  10. Cross-linked potato starch-based blend films using ascorbic acid as a plasticizer.

    Science.gov (United States)

    Yoon, Soon-Do

    2014-02-26

    The main objects of this study were to prepare the cross-linked potato starch/polyvinyl alcohol blend films with ascorbic acid (AsA) added as a plasticizer with and without heat curing and to examine their mechanical properties, elongation at break, degree of swelling, solubility, water vapor absorption, thermal properties, optical properties, and biodegradability. The specific surface area, pore volume, and topography of the films with and without heat curing were also investigated via nitrogen adsorption and desorption isotherms and atomic force microscopy analysis. The results indicate that the cured films possess mechanical, thermal, and optical properties enhanced compared to those of noncured films. The mechanical and water barrier properties of the AsA-added film were also found to be superior to those of other films with polyol plasticizers (glycerol and xylitol). The biodegradability test revealed that the prepared films are degraded by ~35-80% after 165 days. PMID:23909738

  11. [Preclinical toxicological study of theraphthal-Lio and binary catalytic system "theraphthal-Lio+ascorbic acid"].

    Science.gov (United States)

    Mikha?lova, L M; Koniaeva, O N; Chlenova, E L; Merkulova, I B; Ermakova, N P; Gavrilova, T N; Sergeev, A A

    2001-01-01

    Pre-clinical toxicologic studies were conducted of a new drug teraphtal-Lio (TPh) and a teraphtal-Lio + ascorbic acid (TPh + AA) catalytic system recommended for binary catalytic therapy of malignant tumors. Quantitative criteria for "acute" and "chronic" toxicity of TPh and TPh + AA were established, which describe their toxic effects in single or multiple application. The coefficient of specific sensitivity and cumulation index for TPh and TPh + AA were determined. The toxicodynamic characteristics of TPh and TPh + AA were investigated. The results were used to prognose pulmonary, cardio-vascular, hemato- and hepatotoxic as well as hemodynamic and ophthalmologic disorders and functional changes in the central nervous system involved in clinical use of TPh and TPh + AA. PMID:11826491

  12. Cadmium sulfide photocatalysed reduction of malachite green by ascorbic acid and EDTA as reductants

    Scientific Electronic Library Online (English)

    Shilpa, Kothari; Anil, Kumar; Ritu, Vyas; Rakshit, Ameta; Pinki B., Punjabi.

    1821-18-01

    Full Text Available SciELO Brazil | Language: English Abstract in portuguese Foi efetuada a fotoredução do verde de malaquita na presença de CdS como fotocatalizador e ácido ascorbico/EDTA como redutores. Foram estudados os efeitos de diferentes parâmetros como pH, concentração de verde de malaquita, redutores, quantidade de semicondutor e intensidade de luz, na velocidade d [...] a reação fotocatalítica. Levando em conta os dados obtidos propomos um de mecanismo.para a fotoredução do verde de malaquita. Abstract in english The photoreduction of malachite green in presence of CdS as photocatalyst and ascorbic acid/EDTA as reductants has been carried out. The effect of different parameters like pH, concentration of malachite green, reductants, amount of semiconductor and light intensity on the rate of photocatalytic rea [...] ction has been studied. On the basis of observed data, a tentative mechanism for the photoreduction of malachite green has been proposed.

  13. Ascorbic acid-functionalized Ag NPs as a probe for colorimetric sensing of glutathione

    Science.gov (United States)

    D'souza, Stephanie L.; Pati, Ranjan; Kailasa, Suresh Kumar

    2014-10-01

    In this work, we report the use of ascorbic acid-capped silver nanoparticles (AA-Ag NPs) as a probe for selective colorimetric detection of glutathione (GSH) in aqueous solution. This detection system was based on the GSH-induced aggregation of AA-Ag NPs, resulting in drastic changes in the absorption spectra and color of the AA-Ag NPs system. The GSH-induced AA-Ag NPs aggregation was confirmed by UV-visible spectrometry, dynamic light scattering (DLS) and transmission electron microscopic (TEM) techniques. Under optimal conditions, this method exhibited good linearity over the concentration ranges from 5.0 to 50 µM, with the limit of detection 2.4 × 10-7 M. This method was successfully applied to detect GSH in the presence of other biomolecules, which confirms that this probe can be used for the detection of GSH in real samples.

  14. An adult case of cerebral malakoplakia successfully cured by treatment with antibiotics, bethanechol and ascorbic acid.

    Science.gov (United States)

    Fudaba, Hirotaka; Ooba, Hiroshi; Abe, Tatsuya; Kamida, Tohru; Wakabayashi, Yukihiro; Nagatomi, Hirofumi; Fujiki, Minoru

    2014-07-15

    Cerebral malakoplakia is a very rare chronic inflammatory disease. We herein report the case of a 49-year-old female who presented with a slowly progressive speech disturbance and right hemiparesis. Computed tomography and magnetic resonance imaging showed irregular enhanced mass lesions with numerous scattered areas of calcification in the left insula, thalamus and basal ganglia. Histopathologically, the biopsy specimen showed basophilic laminated inclusion bodies and intracellular and extracellular calculospherules, usually with a typical targetoid appearance (Michaelis-Gutmann bodies). Treatment with antibiotics, bethanechol and ascorbic acid improved her symptoms in association with a decrease in the abnormal calcification and enhancement. The cerebral malakoplakia mimicked a brain tumor in terms of the patient's clinical course and neuroradiological image findings; however, it was successfully cured with medical treatment. This case provides evidence that the pathogenesis of cerebral malakoplakia is deeply tied to bacterial infection and that medical treatment is effective in cases of this disease. PMID:24863007

  15. Uptake of dehydroascorbic acid and ascorbic acid to isolated nerve terminals and secretory granules from ox neurohypophyses

    DEFF Research Database (Denmark)

    Thorn, N A; Nielsen, F S

    1986-01-01

    When uptake of L-[14C]ascorbic acid ([14C]AA) to various organs in guinea-pigs was studied after intracardiac injection, the adenohypophysis, pars intermedia, and the neurohypophysis had an uptake per milligramme protein which was about half of the uptake to the adrenals. Adrenal uptake was 20 +/- 2.8 pmol mg-1 protein microCi-1 injected. The uptake to the different parts of the hypophysis was considerably higher than the uptake to pancreas, liver, kidney, spleen and other organs. When isolated nerve endings (neurosecretosomes) from ox neurohypophyses were incubated with a medium containing labelled dehydroascorbic acid ([14C]DHA), the uptake was much slower than when the medium contained labelled ascorbic acid. The uptake of [14C]DHA showed a linear dependence on concentration, and was not influenced by addition of Mg2+ and ATP. Addition of Mg2+ + ATP, omission of Ca2+ and Mg2+ or exchange of Na+ in the medium with K+ had no effect on the uptake of ascorbic acid. When isolated secretory granules from ox neurohypophyses were incubated with a medium containing [14C]DHA, uptake was considerably faster than the uptake when they were incubated in a medium containing [14C]AA. The uptake of dehydroascorbic acid was linear with the concentration in the medium and was not changed by addition of Mg2+ ATP. Addition of 10 mM NH4Cl or exchange of 120 mM K+ in the incubation medium with Na+ did not change the uptake of dehydroascorbic acid. The contents of copper, zinc, iron and cobalt were determined in isolated nerve endings (A) and membranes (B) as well as in lysate (C) from isolated neurosecretory granules. The results (in nmol mg-1 protein) were for Cu: (A): 0.25 +/- 0.01 (SEM), (B): 0.67 +/- 0.16, (C): 0.22 +/- 0.06; for Zn: (A): 0.53 +/- 0.13, (B): 6.97 +/- 0.75, (C): 1.8 +/- 0.53; and for Fe: (A): 15.6 +/- 1.9, (B): 6.92 +/- 0.32, (C): 3.15 +/- 0.43. In all preparations the cobalt content was below the detection limit (less than 5 pmol mg-1 protein).

  16. Ascorbic acid rescues cardiomyocyte development in Fgfr1(-/-) murine embryonic stem cells.

    Science.gov (United States)

    Crescini, Elisabetta; Gualandi, Laura; Uberti, Daniela; Prandelli, Chiara; Presta, Marco; Dell'Era, Patrizia

    2013-01-01

    Fibroblast growth factor receptor 1 (Fgfr1) gene knockout impairs cardiomyocyte differentiation in murine embryonic stem cells (mESC). Here, various chemical compounds able to enhance cardiomyocyte differentiation in mESC [including dimethylsulfoxide, ascorbic acid (vitC), free radicals and reactive oxygen species] were tested for their ability to rescue the cardiomyogenic potential of Fgfr1(-/-) mESC. Among them, only the reduced form of vitC, l-ascorbic acid, was able to recover beating cell differentiation in Fgfr1(-/-) mESC. The appearance of contracting cells was paralleled by the expression of early and late cardiac gene markers, thus suggesting their identity as cardiomyocytes. In the attempt to elucidate the mechanism of action of vitC on Fgfr1(-/-) mESC, we analyzed several parameters related to the intracellular redox state, such as reactive oxygen species content, Nox4 expression, and superoxide dismutase activity. The results did not show any relationship between the antioxidant capacity of vitC and cardiomyocyte differentiation in Fgfr1(-/-) mESC. No correlation was found also for the ability of vitC to modulate the expression of pluripotency genes. Then, we tested the hypothesis that vitC was acting as a prolyl hydroxylase cofactor by maintaining iron in a reduced state. We first analyze hypoxia inducible factor (HIF)-1? mRNA and protein levels that were found to be slightly upregulated in Fgfr1(-/-) cells. We treated mESC with Fe(2+) or the HIF inhibitor CAY10585 during the first phases of the differentiation process and, similar to vitC, the two compounds were able to rescue cardiomyocyte formation in Fgfr1(-/-) mESC, thus implicating HIF-1? modulation in Fgfr1-dependent cardiomyogenesis. PMID:22735182

  17. Modification of Death rate and Disturbances induced in the Levels of serum total Lipids and free fatty acids of irradiated rats by ascorbic acid and serotonin

    International Nuclear Information System (INIS)

    Intraperitoneal injection of normal rats with ascorbic acid (10 mg/100 g body weight ) or serotonin (2 mg/100 g body weight) had no harmful effect on the life span. Moreover, the levels of serum total lipids and free fatty acids did not show any significant changes at 3, 7, 10 and 14 days after injection. Administration of ascorbic acid or serotonin to rats at the pre mentioned doses, 15 minutes, before gamma irradiation at 7.5 Gy (single dose ) improved the survival time of rats and the hyperlipemic state recorded after radiation exposure

  18. Ion exchange separation of carrier-free 140Ba and 140La from their equilibrium mixture using nitrilotriacetic acid and ascorbic acid as eluents

    International Nuclear Information System (INIS)

    A simple cation exchange procedure for separation of 140Ba- 140La using Dowex 50W-X8 and nitrilotriacetic acid or ascorbic acid as the eluent has been described. The optimal separation of the daughter from the parent has been achieved using a 4% Na-nitrilotriacetate or Na-ascorbate solution at pH 7. The parent, 140Ba, left in the column can be eluted with dilute hydrochloric acid or it can be retained in the column for milking off the daughter, 140La, when needed. The radiochemical purity of the separated isotopes, 140Ba and 140La, were verified by ?-ray spectrometry. (author)

  19. Antitumoral activity of L-ascorbic acid-poly-D,L-(lactide-co-glycolide nanoparticles containing violacein

    Directory of Open Access Journals (Sweden)

    Dorival Martins

    2010-01-01

    Full Text Available Dorival Martins1, Lucas Frungillo2, Maristela C Anazzetti2, Patrícia S Melo3, Nelson Durán11Institute of Chemistry, Biological Chemistry Laboratory, Universidade Estadual de Campinas-UNICAMP, C.P. 6154, CE P 13083-970, Campinas, SP, Brazil; 2Institute of Biology, Cell Cultures and Biopharmaceutical Laboratory, Universidade Estadual de Campinas, UNICAMP, Campinas, SP, Brazil; 3Campinas Integrated Metropolitan Faculties-METROCAMP, Campinas, SP, BrazilAbstract: It has been demonstrated that tumoral cells have a higher uptake of ascorbic acid compared to normal cells. This differential characteristic can be used as a way to improve the specificity of antitumoral compounds if combined with polymeric drug delivery systems. The aim of this study was to prepare, characterize and evaluate the antitumoral activity of poly-D,L-(lactide-co-glycolide 50:50 loading the antitumoral compound violacein and capped with L-ascorbic acid. Nanoparticles were prepared using the nanoprecipitation method and morphologically characterized by scanning electron microscopy (SEM. The average diameter and Zeta potential were determined by photon correlation spectroscopy method (PCS, and assays were carried out to determine the content of ascorbic acid and in vitro drug release kinetics. The antitumoral activity of this system was also evaluated against HL-60 cells by tetrazolium reduction assay. Nanoparticles with size distribution between 300–400 nm and strong negative outer surface (-40 mV were obtained by this method. Analysis of ascorbic acid content showed that this compound was mainly localized on the external surface of nanoparticles. Violacein loading efficiency was determined as 32% ± 1% and this drug was gradually released from nanoparticles at different rates depending on the composition of the release media. In addition, this system was observed to be 2 × more efficient as an antitumoral compared with free violacein.Keywords: violacein, ascorbic acid, nanoparticles, PLGA

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

    Energy Technology Data Exchange (ETDEWEB)

    Günther, T-hat nia Mara Fischer; Kviecinski, Maicon Roberto; Baron, Carla Cristine; Felipe, Karina Bettega; Farias, Mirelle Sifroni; Ourique da Silva, Fabiana; Bücker, Nádia Cristina Falcão [Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis (Brazil); Pich, Claus Tröger [Campus de Araranguá, Universidade Federal de Santa Catarina, Araranguá (Brazil); Ferreira, Eduardo Antonio [Universidade de Brasília, Faculdade de Ceilândia, DF (Brazil); Filho, Danilo Wilhelm [Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis (Brazil); Verrax, Julien; Calderon, Pedro Buc [Toxicology and Cancer Biology Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels (Belgium); Pedrosa, Rozangela Curi, E-mail: rozangelapedrosa@gmail.com [Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis (Brazil)

    2013-01-18

    Graphical abstract: -- Abstract: Pharmacological doses of ascorbate were evaluated for its ability to potentiate the toxicity of sodium orthovanadate (Na{sub 3}VO{sub 4}) in tumor cells. Cytotoxicity, inhibition of cell proliferation, generation of ROS and DNA fragmentation were assessed in T24 cells. Na{sub 3}VO{sub 4} was cytotoxic against T24 cells (EC{sub 50} = 5.8 ?M at 24 h), but in the presence of ascorbate (100 ?M) the EC{sub 50} fell to 3.3 ?M. Na{sub 3}VO{sub 4} plus ascorbate caused a strong inhibition of cell proliferation (up to 20%) and increased the generation of ROS (4-fold). Na{sub 3}VO{sub 4} did not directly cleave plasmid DNA, at this aspect no synergism was found occurring between Na{sub 3}VO{sub 4} 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. Na{sub 3}VO{sub 4} alone, or combined with ascorbate, increased catalase activity, but only Na{sub 3}VO{sub 4} plus ascorbate increased superoxide dismutase activity (up to 4-fold). Oxidative damage on proteins and lipids was higher due to the treatment done with Na{sub 3}VO{sub 4} plus ascorbate (2–3-fold). Ascorbate potentiated apoptosis in tumor cells from mice treated with Na{sub 3}VO{sub 4}. The results indicate that pharmacological doses of ascorbate enhance the generation of ROS induced by Na{sub 3}VO{sub 4} 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.

  1. Ascorbic acid is a dose-dependent inhibitor of adipocyte differentiation, probably by reducing cAMP pool

    Science.gov (United States)

    Rahman, Fryad; Al Frouh, Fadi; Bordignon, Benoit; Fraterno, Marc; Landrier, Jean-François; Peiretti, Franck; Fontes, Michel

    2014-01-01

    Ascorbic acid (AA) is the active component of vitamin C and antioxidant activity was long considered to be the primary molecular mechanism underlying the physiological actions of AA. We recently demonstrated that AA is a competitive inhibitor of adenylate cyclase, acting as a global regulator of intracellular cyclic adenosine monophosphate (cAMP) levels. Our study, therefore, aimed to determine new targets of AA that would account for its potential effect on signal transduction, particularly during cell differentiation. We demonstrated that AA is an inhibitor of pre-adipocyte cell line differentiation, with a dose-dependent effect. Additionally, we describe the impact of AA on the expression of genes involved in adipogenesis and/or the adipocyte phenotype. Moreover, our data suggest that treatment with AA partially reverses lipid accumulation in mature adipocytes. These properties likely reflect the function of AA as a global regulator of the cAMP pool, since an analog of AA without any antioxidant properties elicited the same effect. Additionally, we demonstrated that AA inhibits adipogenesis in OP9 mesenchymal cell line and drives the differentiation of this line toward osteogenesis. Finally, our data suggest that the intracellular transporter SVCT2 is involved in these processes and may act as a receptor for AA. PMID:25364736

  2. Effects of salinity and ascorbic acid on growth, water status and antioxidant system in a perennial halophyte.

    Science.gov (United States)

    Hameed, Abdul; Gulzar, Salman; Aziz, Irfan; Hussain, Tabassum; Gul, Bilquees; Khan, M Ajmal

    2015-01-01

    Salinity causes oxidative stress in plants by enhancing production of reactive oxygen species, so that an efficient antioxidant system, of which ascorbic acid (AsA) is a key component, is an essential requirement of tolerance. However, antioxidant responses of plants to salinity vary considerably among species. Limonium stocksii is a sub-tropical halophyte found in the coastal marshes from Gujarat (India) to Karachi (Pakistan) but little information exists on its salt resistance. In order to investigate the role of AsA in tolerance, 2-month-old plants were treated with 0 (control), 300 (moderate) and 600 (high) mM NaCl for 30 days with or without exogenous application of AsA (20 mM) or distilled water. Shoot growth of unsprayed plants at moderate salinity was similar to that of controls while at high salinity growth was inhibited substantially. Sap osmolality, AsA concentrations and activities of AsA-dependant antioxidant enzymes increased with increasing salinity. Water spray resulted in some improvement in growth, indicating that the growth promotion by exogenous treatments could partly be attributed to water. However, exogenous application of AsA on plants grown under saline conditions improved growth and AsA dependent antioxidant enzymes more than the water control treatment. Our data show that AsA-dependent antioxidant enzymes play an important role in salinity tolerance of L. stocksii. PMID:25603966

  3. Protective role of ascorbic acid isolated from Cissus quadrangularis on NSAID induced toxicity through immunomodulating response and growth factors expression.

    Science.gov (United States)

    Jainu, Mallika; Mohan, Kunju Vijai

    2008-12-20

    The present study investigate the effect of ascorbic acid, the major bioactive component isolated from Cissus quadrangularis extract (CAA) on inflammatory cytokines and growth factors in non-steroidal anti-inflammatory drug (NSAID) induced gastric ulcer. Analysis of serum cytokine profile using enzymelinked immunosorbent assay (ELISA) showed a drastic increase in interleukin (IL)-1beta, IL-6, tumour necrosis factor-alpha (TNF)-alpha, interferon-gamma (IFN-gamma) and decrease in IL-10, Il-4 and prostaglandin E2 (PGE2) levels in NSAID (aspirin) treated rats. The reduction of growth factors such as transforming growth factor-alpha (TGF)-alpha and vascular endothelial cell growth factor (VEGF) by aspirin was determined by immunohistochemistry method. Administration of CAA produced significant protection against aspirin induced gastric toxicity by showing significant increase in PGE2, TGF-alpha, VEGF expression and accompanied by a significant inhibition of nitric oxide and regulating the levels of cytokines in rats. These findings suggest that CAA prevents gastric ulcer formation due to its immunomodulatory effect, antioxidant activity along with the ability to modulate PG synthesis and up-regulation of the growth factors. PMID:18773975

  4. A biosensor based on zucchini (Cucurbita pepo L.) homogenate as a biorecognition layer for ascorbic acid determination.

    Science.gov (United States)

    Sezgintürk, Mustafa Kemal; Koca, Halit Bu?ra; Ozben, Yavuz Selim; Dinçkaya, Erhan

    2010-08-01

    An amperometric biosensor based on zucchini (Cucurbita pepo) tissue homogenate is presented. The zucchini tissue homogenate was crosslinked with gelatine using glutaraldehyde and fixed on a pretreated teflon membrane. The zucchini tissue contained the enzyme ascorbate oxidase and this enzyme catalyzed the oxidation of ascorbic acid in the presence of dissolved oxygen. The principle of the measurements was based on the determination of the decrease in the dissolved oxygen level. Determinations were carried out by standard curves, which were obtained by the measurement of the decrease in the oxygen level related to ascorbic acid concentration. Optimization and characterization studies of the biosensor were carried out in detail. First of all, the amounts of zucchini tissue homogenate, gelatin, and glutaraldehyde percentage were optimized. Experimental parameters such as buffer system, pH, buffer concentration, and temperature were also optimized carefully. Thermal stability, storage stability, and repeatability of the biosensor were investigated. A linear response was observed from 5x10(-6) M to 1.2x10(-3) M ascorbic acid. Finally, the results of some plant and drug samples analyzed with the presented biosensor compared with the spectrophotometric method (Tillman reagent) used as a reference. PMID:20384439

  5. Rapid, sensitive and simultaneous determination of ascorbic and uric acids in human plasma by ion-exclusion HPLC-UV,

    OpenAIRE

    Ferin, Rita; Pava?o, Maria Leonor; Baptista, Jose?

    2013-01-01

    OBJECTIVES: Ascorbic (AA) and uric (UA) acids act as antioxidants and are capable to react with biologically relevant oxidants. We aimed to developed a simple, rapid, sensitive, and accurate ion-exclusion HPLC-UV methodology for the simultaneously determination of AA and UA in human plasma. METHODS: Analytical pre-requisites, such as the use of heparin as an anticoagulant and meta-phosphoric acid as a stabilizer were added for accurate and reliable measurements. Chromatographic separation was...

  6. Rheological Characteristics of Gluten after Modified by DATEM, Ascorbic Acid, Urea and DTT Using Creep-Recovery Test

    OpenAIRE

    Pavalee Chompoorat; Amogh Ambardekar; Steven Mulvaney; Patricia Rayas-Duarte

    2013-01-01

    The effects of diacetyl tartaric acid ester of monoglycerides (DATEM), ascorbic acid (AA), urea, and dithiothreitol (DTT) on viscoelastic properties of commercial hard red winter wheat gluten were investigated. A constant shear stress of 40 Pa was applied to gluten during creep-recovery test. Experimental creep-recovery compliance responses were fitted into a Burgers model with four elements accounting for characteristics of pure elastic (spring), viscoelastic (spring-dashpots elements),...

  7. Protective effect of ascorbic acid against oxidative damage induced by hydrogen peroxide in cultured human peripheral blood lymphocytes

    OpenAIRE

    Siddique, Yasir Hasan; Beg, Tanveer; Afzal, Mohammad

    2009-01-01

    Hydrogen peroxide is one of the reactive oxygen species for cellular injury. It is overproduced during oxidative stress and is known to damage proteins, nucleic acids and cell membranes. The present study was aimed to study the protective effect of ascorbic acid against the toxic doses of hydrogen peroxide using lipid peroxidation and cytokinesis blocked micronucleus assay. Hydrogen peroxide was studied at 50, 100 and 200?M and was found to increase a dose dependent increase in lipid peroxid...

  8. Ascorbic acid attenuates scopolamine-induced spatial learning deficits in the water maze

    OpenAIRE

    Harrison, F. E.; Hosseini, A. H.; Dawes, S. M.; Weaver, S.; May, J. M.

    2009-01-01

    Vitamin C (ascorbate) has important antioxidant functions that can help protect against oxidative stress in the brain and damage associated with neurodegenerative disorders such as Alzheimer’s disease. When administered parenterally ascorbate can bypass saturable uptake mechanisms in the gut and thus higher tissue concentrations can be achieved than by oral administration. In the present study we show that ascorbate (125 mg/kg) administered intraperitoneally (i.p.) 1-hour before testing, pa...

  9. Influence of ascorbic acid on in vivo amidation of alpha-melanocyte stimulating hormone in guinea pig pituitary

    DEFF Research Database (Denmark)

    Fenger, M; Hilsted, L

    1988-01-01

    The effect of ascorbic acid depletion on the amidation of alphamelanocyte stimulating hormone (alpha MSH) was studied in vivo in guinea pig pituitary. After four weeks, the concentration of ascorbic acid was 1.20 +/- 0.11 mumol/g tissue (mean +/- SD) in the pituitary and 0.34 +/- 0.07 mumol/g tissue in the cerebral cortex from the depleted animals versus 7.58 +/- 0.08 and 1.51 +/- 0.32 mumol/g tissue, respectively, in the control animals. In the pituitaries from the animals depleted of ascorbate (N = 4), the relative amount of alpha MSH was reduced to approximately half the values obtained in the control group (from 66.5 +/- 4.6% of total ACTH-related peptides to 31.1 +/- 12.2% (P less than 0.0025]. A concomitant increase (from 5.9 +/- 3.1% to 19.4 +/- 4.3% (P less than 0.004] in ACTH (1-14) (the glycine-extended precursor of alpha MSH) immunoreactivity and a smaller increase in ACTH (1-39) immunoreactivity was observed in the depleted guinea pigs. Gel chromatography and reversed-phase high-performance luquid chromatography showed that the alpha MSH and ACTH (1-14) immunoreactivity was of low molecular weight and partly mono- or diacetylated. Depletion of ascorbic acid had no influence on the degree of acetylation of alpha MSH and ACTH (1-14). It is concluded that depletion of ascorbic acid reduces the in vivo amidation of ACTH (1-14) in the guinea pig pituitary.

  10. All-solid-state potentiometric sensors for ascorbic acid by using a screen-printed compatible solid contact

    Energy Technology Data Exchange (ETDEWEB)

    Veltsistas, Panayotis G.; Prodromidis, Mamas I.; Efstathiou, Constantinos

    2004-01-23

    The development of all-solid-state potentiometric ion selective electrodes for monitoring of ascorbic acid, by using a screen-printed compatible solid contact is described. The applied methodology is based on the use of PVC membrane modified with some firstly-tested ionophores (triphenyltin(IV)chloride, triphenyltin(IV)hydroxide and palmitoyl-L-ascorbic acid) and a novel one synthesized in our laboratory (dibutyltin(IV) diascorbate). Synthesis protocol and some preliminary identification studies are given. A conductive graphite-based polymer thick film ink was used as an internal solid contact between the graphite electrode and the PVC membrane. The presence and the nature of the solid contact (plain or doped with lanthanum 2,6-dichlorophenolindophenol (DCPI)) seem to enhance the analytical performance of the electrodes in terms of sensitivity, dynamic range, and response time. The analytical performance of the constructed electrodes was evaluated with potentiometry, constant-current chronopotentiometry and electrochemical impedance spectroscopy (EIS). The interference effect of various compounds was also tested. The potential response of the optimized Ph{sub 3}SnCl-based electrode was linear against ascorbic acid concentration range 0.005-5.0 mM. The applicability of the proposed sensors in real samples was also tested. The detection limit was 0.002 mM ascorbic acid (50 mM phosphate, pH 5 in 50 mM KCl). The slope of the electrodes was super-Nernstian and pH dependent, indicating a mechanism involving a combination of charge transfer and ion exchange processes. Fabrication of screen-printed ascorbate ISEs has also been demonstrated.

  11. Radiolytic study of the action of perhydroxyl radicals with ascorbic acid

    International Nuclear Information System (INIS)

    This paper shows that the difficulties encountered up to now about the interpretation of the radiolysis of aerated ascorbic acid (AH2) solutions, were due to a low oxygen concentration. For oxygen-saturated solutions, the yield is about G(-AH2) = G/sub OH/ + G/sub H/ + G/sub eaq-/ according to the mechanism, and formic acid has no influence on it. For lower concentrations of oxygen, in the presence of air, the action of oxygen on AH radical being slow, the yield decreases because of competitive reactions. Formic acid accentuates the decrease. This hypothesis allows a quantitative interpretation of the experimental results which explains the influence of AH2 concentration (1) by the presence of an oxidation chain by O2, initiated by OH and HO2 radicals; this chain, however, is not important even at the highest concentrations, and (2) by a dilution effect allowing partial disproportionation of HO2 radicals; the kinetic calculation leads to the value of the rate constant of oxidation of AH2 by HO2: k8 = 3300 M-1 sec-1

  12. Study on the Ascorbic Acid Content of rose Hip fruit Depending on Stationary Conditions

    Directory of Open Access Journals (Sweden)

    Sorina Ropciuc

    2011-10-01

    Full Text Available The dog rose area includes southern and central Europe, reaching southern Scandinavia; it is also found in Asia Minor, Central Asia and North Africa. In our country, Rosa canina is the most widespread of the many species of Rosa, common in all areas. The components of the station, known also as the „stationary factors” affect differently the plant life and their chemical composition. Cynosbati fructus is the false fruit of Rosa canina L. (Rosaceae, known in Romanian as rose hip. The rose hip contain as active ingredients 500-1000 % vitamin C, 600-10000 mg% carotenoids, pectin, dextrin, vitamins B2, E, PP, flavone, sugars, organic acids, tannins, volatile oil, vanillin, triterpenoid saponosides, beta-sitosterol, fat (lecithin, glycerides of fatty acids in seeds, minerals (potassium, calcium, magnesium, iron. Vitamin C (ascorbic acid plays an important role in human body. The greatest amount is found in plants which reached maturity. It is concentrated in the rose hip flesh. Solutions easily destroyit in the presence of UV, of copper, silver, iron and oxidative enzymes traces. Vitamin C participates actively in all processes of oxidoreductions of the living cell. Its lack in food causes the disease called scurvy which manifests itself by inflammated and bleeding gums, tooth loss. Rose hip fruits are known as medicines since prehistoric times.

  13. Synergistic effects of tea polyphenols and ascorbic acid on human lung adenocarcinoma SPC-A-1 cells.

    Science.gov (United States)

    Li, Wei; Wu, Jian-xiang; Tu, You-ying

    2010-06-01

    Tea polyphenols have been shown to have anticancer activity in many studies. In the present study, we investigated effects of theaflavin-3-3'-digallate (TF(3)), one of the major theaflavin monomers in black tea, in combination with ascorbic acid (AA), a reducing agent, and (-)-epigallocatechin-3-gallate (EGCG), the main polyphenol presented in green tea, in combination with AA on cellular viability and cell cycles of the human lung adenocarcinoma SPC-A-1 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay showed that the 50% inhibition concentrations (IC(50)) of TF(3), EGCG, and AA on SPC-A-1 cells were 4.78, 4.90, and 30.62 micromol/L, respectively. The inhibitory rates of TF(3) combined with AA (TF(3)+AA) and EGCG combined with AA (EGCG+AA) at a molar ratio of 1:6 on SPC-A-1 cells were 54.4% and 45.5%, respectively. Flow cytometry analysis showed that TF(3)+AA and EGCG+AA obviously increased the cell population in the G(0)/G(1) phase of the SPC-A-1 cell cycle from 53.9% to 62.8% and 60.0%, respectively. TF(3)-treated cells exhibited 65.3% of the G(0)/G(1) phase at the concentration of its IC(50). Therefore, TF(3)+AA and EGCG+AA had synergistic inhibition effects on the proliferation of SPC-A-1 cells, and significantly held SPC-A-1 cells in G(0)/G(1) phase. The results suggest that the combination of TF(3) with AA or EGCG with AA enhances their anticancer activity. PMID:20506578

  14. Synergistic effects of tea polyphenols and ascorbic acid on human lung adenocarcinoma SPC-A-1 cells*

    Science.gov (United States)

    Li, Wei; Wu, Jian-xiang; Tu, You-ying

    2010-01-01

    Tea polyphenols have been shown to have ansticancer activity in many studies. In the present study, we investigated effects of theaflavin-3-3?-digallate (TF3), one of the major theaflavin monomers in black tea, in combination with ascorbic acid (AA), a reducing agent, and (?)-epigallocatechin-3-gallate (EGCG), the main polyphenol presented in green tea, in combination with AA on cellular viability and cell cycles of the human lung adenocarcinoma SPC-A-1 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay showed that the 50% inhibition concentrations (IC50) of TF3, EGCG, and AA on SPC-A-1 cells were 4.78, 4.90, and 30.62 ?mol/L, respectively. The inhibitory rates of TF3 combined with AA (TF3+AA) and EGCG combined with AA (EGCG+AA) at a molar ratio of 1:6 on SPC-A-1 cells were 54.4% and 45.5%, respectively. Flow cytometry analysis showed that TF3+AA and EGCG+AA obviously increased the cell population in the G0/G1 phase of the SPC-A-1 cell cycle from 53.9% to 62.8% and 60.0%, respectively. TF3-treated cells exhibited 65.3% of the G0/G1 phase at the concentration of its IC50. Therefore, TF3+AA and EGCG+AA had synergistic inhibition effects on the proliferation of SPC-A-1 cells, and significantly held SPC-A-1 cells in G0/G1 phase. The results suggest that the combination of TF3 with AA or EGCG with AA enhances their anticancer activity. PMID:20506578

  15. Oral high dose ascorbic acid treatment for one year in young CMT1A patients: a randomised, double-blind, placebo-controlled phase II trial

    OpenAIRE

    de Visser Marianne; Baas Frank; Vermeulen Marinus; de Haan Rob J; Verhamme Camiel; van Schaik Ivo N

    2009-01-01

    Abstract Background High dose oral ascorbic acid substantially improved myelination and locomotor function in a Charcot-Marie-Tooth type 1A mouse model. A phase II study was warranted to investigate whether high dose ascorbic acid also has such a substantial effect on myelination in Charcot-Marie-Tooth type 1A patients and whether this treatment is safe. Methods Patients below age 25 years were randomly assigned to receive placebo or ascorbic acid (one gram twice daily) in a double-blind fash...

  16. [Application of the chromatographic-spectrophotometric method for the analytical control of l-ascorbic acid in pharmaceutical and plant material].

    Science.gov (United States)

    Hachu?a, U; Zawisza, B; Winkler, W

    2000-01-01

    The conditions of chromatographic separation allowing the isolation of L-ascorbic acid from its products of decomposition and other accompanying substances in the determined pharmaceutic preparation and plant materials were established. The isolated L-ascorbic acid was signed by the extractive--spectrophotometric method using coupled redox-complexation reactions with iron(III), 1, 10 phenantroline and bromophenol blue system. The analytical procedure allowing the evaluation of durability of vitamin C in multivitamin "Vitaral" preparate was described. The procedure was used also for the evaluation of the loss of L-ascorbic acid in the parsley and lovage in the process of drying and storage. PMID:10846938

  17. Ascorbic acid, garlic extract and taurine alleviate cadmium-induced oxidative stress in freshwater catfish (Clarias batrachus)

    International Nuclear Information System (INIS)

    An experiment was conducted to investigate bioaccumulation potential of cadmium (Cd) and changes in oxidative stress indices in liver and kidney tissues from Cd-exposed catfish (Clarias batrachus) with or without simultaneous treatment of water with ascorbic acid, garlic extract or taurine. C. batrachus (n = 324) with average length of 20 ± 4 cm and weight of 86 ± 5 g were used for the present investigation. Fishes were divided into nine groups (I to IX) each comprising 36 fishes. The fishes of groups II, III, IV and V were challenged with 5 ppm of cadmium chloride monohydrate (CdCl2.H2O), whereas groups VI, VII, VIII and IX were exposed to 10 ppm CdCl2.H2O solution for a period of 45 days. Group I was kept as negative control and the fishes of this group were maintained in water containing no added Cadmium. Group II and VI were maintained as Cd exposed non treated control to serve as positive controls. Fishes of III and VII, IV and VIII, V and IX received ascorbic acid (5 ppm), extract of dried garlic (5 ppm) or taurine (5 ppm), respectively during the entire experiment period. The concentrations of Cd in liver and kidney increased significantly following exposure to Cd and the level continued to rise with the increase in exposure duration. Treatment of tank water with ascorbic acid, garlic or taurine significantly reduced the Cd concentrations in tissues compared to the positive control group, but the level in Cd exposedntrol group, but the level in Cd exposed groups was greater than the negative control group. Fishes exposed to Cd and treated with ascorbic acid, garlic or taurine had reduced oxidative stress as evidenced from lower concentration of lipid peroxides and higher activities of superoxide dismutase and catalase in liver, kidney and erythrocytes compared to fishes exposed to Cd. The reduction in Cd induced oxidative stress was highest in ascorbic acid treated group followed by garlic and taurine treatment. The results suggest that ascorbic acid, garlic and taurine have potential to reduce tissue accumulation of Cd and associated oxidative stress in freshwater catfish.

  18. Ascorbic acid, garlic extract and taurine alleviate cadmium-induced oxidative stress in freshwater catfish (Clarias batrachus)

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Puneet, E-mail: puneetbiochem@gmail.com [Aquatic Biotechnology and Fish Pathology Laboratory, Department of Animal Science, M.J.P. Rohilkhand University, Bareilly-243 006 (India); Prasad, Y. [Aquatic Biotechnology and Fish Pathology Laboratory, Department of Animal Science, M.J.P. Rohilkhand University, Bareilly-243 006 (India); Patra, A.K. [West Bengal University of Animal and Fishery Sciences, Kolkata-700037 (India); Ranjan, R.; Swarup, D.; Patra, R.C. [Division of Medicine, Indian Veterinary Research Institute, Izatnagar-243122 (India); Pal, Satya [Env. Eng. Lab., Deptt. of Civil Engineering, I.I.T., Roorkee-247667 (India)

    2009-09-01

    An experiment was conducted to investigate bioaccumulation potential of cadmium (Cd) and changes in oxidative stress indices in liver and kidney tissues from Cd-exposed catfish (Clarias batrachus) with or without simultaneous treatment of water with ascorbic acid, garlic extract or taurine. C. batrachus (n = 324) with average length of 20 {+-} 4 cm and weight of 86 {+-} 5 g were used for the present investigation. Fishes were divided into nine groups (I to IX) each comprising 36 fishes. The fishes of groups II, III, IV and V were challenged with 5 ppm of cadmium chloride monohydrate (CdCl{sub 2}.H{sub 2}O), whereas groups VI, VII, VIII and IX were exposed to 10 ppm CdCl{sub 2}.H{sub 2}O solution for a period of 45 days. Group I was kept as negative control and the fishes of this group were maintained in water containing no added Cadmium. Group II and VI were maintained as Cd exposed non treated control to serve as positive controls. Fishes of III and VII, IV and VIII, V and IX received ascorbic acid (5 ppm), extract of dried garlic (5 ppm) or taurine (5 ppm), respectively during the entire experiment period. The concentrations of Cd in liver and kidney increased significantly following exposure to Cd and the level continued to rise with the increase in exposure duration. Treatment of tank water with ascorbic acid, garlic or taurine significantly reduced the Cd concentrations in tissues compared to the positive control group, but the level in Cd exposed groups was greater than the negative control group. Fishes exposed to Cd and treated with ascorbic acid, garlic or taurine had reduced oxidative stress as evidenced from lower concentration of lipid peroxides and higher activities of superoxide dismutase and catalase in liver, kidney and erythrocytes compared to fishes exposed to Cd. The reduction in Cd induced oxidative stress was highest in ascorbic acid treated group followed by garlic and taurine treatment. The results suggest that ascorbic acid, garlic and taurine have potential to reduce tissue accumulation of Cd and associated oxidative stress in freshwater catfish.

  19. Optimisation of analytical methods for the characterisation of oranges, clementines and citrus hybrids cultivated in Spain on the basis of their composition in ascorbic acid, citric acid and major sugars

    OpenAIRE

    Carballo Marrero, Silvia; Zingarello, Fabrizio A.; Maestre Pe?rez, Salvador; Todoli? Torro?, Jose? Luis; Prats Moya, Soledad

    2014-01-01

    Three HPLC methods were optimised for the determination of citric acid, succinic acid and ascorbic acid using a photodiode array detector and fructose, glucose and sucrose using a refractive index in twenty eight citrus juices. The analysis was completed in

  20. Lipophilization of ascorbic acid: a monolayer study and biological and antileishmanial activities.

    Science.gov (United States)

    Kharrat, Nadia; Aissa, Imen; Sghaier, Manel; Bouaziz, Mohamed; Sellami, Mohamed; Laouini, Dhafer; Gargouri, Youssef

    2014-09-17

    Ascorbyl lipophilic derivatives (Asc-C2 to Asc-C(18:1)) were synthesized in a good yield using lipase from Staphylococcus xylosus produced in our laboratory and immobilized onto silica aerogel. Results showed that esterification had little effect on radical-scavenging capacity of purified ascorbyl esters using DPPH assay in ethanol. However, long chain fatty acid esters displayed higher protection of target lipids from oxidation. Moreover, compared to ascorbic acid, synthesized derivatives exhibited an antibacterial effect. Furthermore, ascorbyl derivatives were evaluated, for the first time, for their antileishmanial effects against visceral (Leishmania infantum) and cutaneous parasites (Leishmania major). Among all the tested compounds, only Asc-C10, Asc-C12, and Asc-C(18:1) exhibited antileishmanial activities. The interaction of ascorbyl esters with a phospholipid monolayer showed that only medium and unsaturated long chain (Asc-C10 to Asc-C(18:1)) derivative esters were found to interact efficiently with mimetic membrane of leishmania. These properties would make ascorbyl derivatives good candidates to be used in cosmetic and pharmaceutical lipophilic formulations. PMID:25148258

  1. Ascorbic acid and citric flavonoids for broilers under heat stress: effects on performance and meat quality

    Scientific Electronic Library Online (English)

    JEM, Peña; SL, Vieira; J, López; RN, Reis; R, Barros; FVF, Furtado; PX, Silva.

    2008-06-01

    Full Text Available The aim of this study was to evaluate the effects of increasing doses of ascorbic acid (AA) and citric flavonoids (quercetin and rutin) on the performance and meat quality characteristics of broilers submitted to cyclic heat stress. Four-hundred one-day-old female Ross 308 were housed in 40 battery [...] cages a in temperature controlled room. Treatments consisted of 0, 250, 500, and 1000 g/ton on of AA + citric flavonoids. Birds were fed ad libitum until 32 day of age. Beginning on day 14 post-hatch until the end of the experiment, in order to simulate cyclic heat stress, the temperature inside the room was increased to 32°C for 5 hours, and decreased until reaching the comfort temperature corresponding to the age of the animals. Birds were slaughtered at 33 days of age, and carcass and commercial cuts yields were determined. Thighs and boneless breast samples were collected and frozen for subsequent analyses of pH, cooking loss, shear force, color, and Thiobarbituric Acid Reactive Substances (TBARS). Significant differences (p

  2. Thermal-driven attachment of gold nanoparticles prepared with ascorbic acid onto indium tin oxide surfaces

    International Nuclear Information System (INIS)

    Thermal-driven attachment of gold nanoparticles (AuNPs), of which size was less than 50 nm, onto the surfaces of indium tin oxide (ITO) is reported as a new phenomenon. This was permitted by preparing AuNPs via the reduction of hydrogen tetrachloroaurate (HAuCl4) with ascorbic acid (AA). While the AuNPs prepared via the AA reduction sparsely attached on the surface of ITO even at room temperature, a heat-up treatment at ca. 75 °C caused denser attachment of AuNPs on ITO surfaces. The attached density and the homogeneity after the thermal treatment were better than those of AuNP/ITO prepared using 3-aminopropyl-trimethoxysilane linker molecules. The denser attachment was observed similarly both by the immersion of ITO samples after the preparations of AuNPs by AA and by the in situ preparation of AuNPs with AA together with ITO samples. Thus, it is considered that the thermal-driven attachment of AuNPs would occur after the formation of AuNPs in the aqueous solutions, not via the growth of AuNPs on ITO surfaces. The preparation of AuNPs with AA would be a key for the thermal-driven attachment because the same attachments were not observed for AuNPs prepared with citrate ions or commercially available tannic acid-capped AuNPs.

  3. Thermal-driven attachment of gold nanoparticles prepared with ascorbic acid onto indium tin oxide surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, Md. Abdul; Oyama, Munetaka, E-mail: oyama.munetaka.4m@kyoto-u.ac.jp [Kyoto University, Department of Material Chemistry, Graduate School of Engineering (Japan)

    2013-05-15

    Thermal-driven attachment of gold nanoparticles (AuNPs), of which size was less than 50 nm, onto the surfaces of indium tin oxide (ITO) is reported as a new phenomenon. This was permitted by preparing AuNPs via the reduction of hydrogen tetrachloroaurate (HAuCl{sub 4}) with ascorbic acid (AA). While the AuNPs prepared via the AA reduction sparsely attached on the surface of ITO even at room temperature, a heat-up treatment at ca. 75 Degree-Sign C caused denser attachment of AuNPs on ITO surfaces. The attached density and the homogeneity after the thermal treatment were better than those of AuNP/ITO prepared using 3-aminopropyl-trimethoxysilane linker molecules. The denser attachment was observed similarly both by the immersion of ITO samples after the preparations of AuNPs by AA and by the in situ preparation of AuNPs with AA together with ITO samples. Thus, it is considered that the thermal-driven attachment of AuNPs would occur after the formation of AuNPs in the aqueous solutions, not via the growth of AuNPs on ITO surfaces. The preparation of AuNPs with AA would be a key for the thermal-driven attachment because the same attachments were not observed for AuNPs prepared with citrate ions or commercially available tannic acid-capped AuNPs.

  4. Phytotoxicity of multi-walled carbon nanotubes on red spinach (Amaranthus tricolor L) and the role of ascorbic acid as an antioxidant

    International Nuclear Information System (INIS)

    Highlights: ? MWNTs are selected for study of the systemic toxicity and the potential influence on red spinach. ? Microscopic observation revealed some adverse effects on root and leaf. ? Cell damage were detected on 15 days after the exposure to MWNTs. ? ROS increase ceased once ascorbic acid was added into media. ? Oxidative stress seems to be the key element responsible for causing the toxicity. - Abstract: Carbon nanotubes (CNTs) are a novel nanomaterial with wide potential applications; however the adverse effects of CNTs following environmental exposure have recently received significant attention. Herein, we explore the systemic toxicity and potential influence of 0–1000 mg L?1 the multi-walled CNTs on red spinach. The multi-walled CNTs exposed plants exhibited growth inhibition and cell death after 15 days of hydroponic culture. The multi-walled CNTs had adverse effects on root and leaf morphology, as observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Raman spectroscopy detected the multi-walled CNTs in leaves. Biomarkers of nanoparticle toxicity, reactive oxygen species (ROS), and cell damage in the red spinach were greatly increased 15 days post-exposure to the multi-walled CNTs. These effects were reversed when the multi-walled CNTs were supplemented with ascorbic acid (AsA), suggesting a role of ROS in the multl-walled CNT-induced toxicity and that the primary mechanism of the multi-walled CNanism of the multi-walled CNTs’ toxicity is oxidative stress.

  5. Methylene blue immobilized on cellulose acetate with titanium dioxide: an application as sensor for ascorbic acid

    Scientific Electronic Library Online (English)

    Andrea A., Hoffmann; Silvio L. P., Dias; Jordana R., Rodrigues; Flavio A., Pavan; Edilson V., Benvenutti; Eder C., Lima.

    Full Text Available SciELO Brazil | Language: English Abstract in portuguese Neste trabalho, o corante azul de metileno foi imobilizado na superfície do acetato de celulose modificado com dióxido de titânio produzindo um material híbrido sólido denominado de CA-TiO2MB. O experimento produziu uma quantidade de 1,8 mmol g-1 de TiO2 incorporado no acetato de celulose e uma quan [...] tidade de 0,170 ± 0,005 mmol g-1 de azul de metileno adsorvido na superfície do CA-TiO2. Um eletrodo de pasta de carbono desse material foi usado para estudar a oxidação eletrocatalítica do ácido ascórbico pelas técnicas de voltametria cíclica e cronoamperometria. O pH da solução não afetou o potencial de pico de anódico nem a corrente de pico anódico ao variar de 3,0 a 7,0. A oxidação do analito ocorreu em 75 mV versus ECS em solução de KCl 1,0 mol L-1 e pH 7,0. A intensidade da corrente de pico anódico variou com a concentração de ácido ascórbico na faixa de 5,0 × 10-4 mol L-1 to 4,5 × 10-3 mol L-1, sendo observada uma correlação linear com um limite de detecção de 15 µmol L-1, limite de quantificação de 50 µmol L-1 e uma sensibilidade de 7,1 µA L mol-1. A resposta do eletrodo foi muito rápida, com um tempo decorrido de 1,0 s, mostrando potencial para ser utilizado como um sensor eletroquímico para a determinação de ácido ascórbico em produtos comerciais. Abstract in english In this work, methylene blue dye was immobilized on the surface of cellulose acetate modified with titanium dioxide, producing a solid hybrid material designated as CA-TiO2MB. The experiment yielded an amount of 1.8 mmol g-1 of TiO2 incorporated in the cellulose acetate and an amount of 0.170 ± 0.00 [...] 5 mmol g-1 of methylene blue adsorbed onto CA-TiO2 surface. A carbon paste electrode of this material was used to study the electrocatalytic oxidation of ascorbic acid by cyclic voltammetric and chronoamperometric techniques. The pH of the solution had no effect on the anodic peak potential and anodic peak current when ranging from 3.0 to 7.0. The oxidation of the analyte occurred at 75 mV versus SCE in 1.0 mol L-1 KCl solution and pH 7.0. The intensity of the anodic peak current varied with the concentration of ascorbic acid from 5.0 × 10-4 mol L-1 to 4.5 × 10-3 mol L-1 and a linear correlation was observed, with a detection limit of 15 µmol L-1, quantification limit of 50 µmol L-1 and a sensitivity of 7.1 µA L mol-1. The electrode response was very fast, with an elapsed time of about 1.0 s, showing the potentiality to be utilized as an electrochemical sensor for determination of ascorbic acid in commercial samples.

  6. Theoretical study on structure, conformation, stability and electronic transition of C4 and C5 anions of ascorbic acid stereoisomers

    Science.gov (United States)

    Dabbagh, Hossein A.; Azami, Fatemeh; Farrokhpour, Hossein; Chermahini, Alireza Najafi

    2014-03-01

    The structures, stabilities, conformational analysis and electronic transitions of L-ascorbic acid anions (four stereoisomers) were studied theoretically. These anions are produced from the de-protonation of C4-H and C5-H sites of L-ascorbic acid stereoisomers. The geometries of these anions were fully optimized in gas phase and aqueous phase in order to determine their relative stabilities. It was observed that the de-protonation at C5 site of two stereoisomers leads to the ring opening in both phases. Isomerization of the L-form to one of the D-form was observed during the optimization of the anions at C5. Conformational analysis (potential energy surface scan) of the opened ring anions was performed in search of energy minima and/or maxima. The absorption electronic transitions of the anions in the UV region were calculated using Time-Dependent Density Functional Theory (TD-DFT).

  7. Flow injection spectrophotometric determination of ascorbic acid with 2,2'-bipyridine in anionic surfactant micellar medium

    International Nuclear Information System (INIS)

    An indirect flow injection spectrophotometric method for the determination of ascorbic acid has been developed using its reducing action on iron(III) in sodium dodecyl sulfate micellar medium. Reduced iron(II) is chelated with 2,2'-bipyridine and is monitored on 520 nm. A single line FIA manifold is used throughout. The linear range of method is 10-100 micro g/ml with equation of straight-line y=-.171+0.0146x. The proposed method is rapid (sample throughput is 54 sample per hour), reproducible (RSD 0.18%) and is fairly sensitive. The procedure is successfully applied to assay ascorbic acid content in pharmaceutical preparations. (author)

  8. The content determination of calcium, magnesium and ascorbic acid in sea buckthorn fruits at vulcan coal dump

    Directory of Open Access Journals (Sweden)

    Andreea BRASOVAN

    2009-11-01

    Full Text Available The study presents data on content determination of calcium, magnesium and ascorbic acid in sea buckthorn fruits collected from Vulcan coal dump. The dump was never covered with soil or fertilizers containing azoth, potassium and phosphorus. The sea buckthorn was planted directly on the sterile and it has an important function in stabilizing the acclivity and fixing the atmospheric azoth with the nodosities on the roots. So, the sea buckthorn becomes widespread plant in coal dumps because it helps to the soil formation. The results obtained after the determination of calcium, magnesium and ascorbic acid from the fruits of this plant were compared with the values already reported in various references, concluding that these differences are insignificant (3.7% for magnesium and 9.4% for calcium. Therefore, the sea buckthorn from the dump can be used in food industry, as well as in pharmaceutics and medicine.

  9. STUDY OF LIPID PEROXIDATION AND SERUM ASCORBIC ACID LEVELS AS INDICES OF OXIDATIVE STRESS IN VARIOUS LUNG DISORDERS

    Directory of Open Access Journals (Sweden)

    Ivvala Anand Shaker1*, Suresh Babu Kondaveeti1, Hemraz Palwan2, Dabburu Kumaraswamy3, Raja G1, S Saleem Basha1

    2012-10-01

    Full Text Available The present study was planned to assess the levels of oxidant and antioxidant in various lung disorders and to evaluate the existence of correlation between oxidant-antioxidant levels. Asthma, Bronchitis, COPD and Lung fibrosis well know chronic inflammatory disorders where disturbances in the oxidative system have been observed. To investigate the lipidperoxidation in terms of plasma MDA and antioxidant capacity in terms of ascorbic acid (Vitamin C were measured. Results revealed statistically significantly Increase serum MDA (P<0.001 and decrease vitamin C (P<0.001 in patients suggestive of oxidative imbalance in various lung disorders was revealed. However there is negative correlation between lipidperoxidation and ascorbic acid levels correlation. The study thus supported the emerging concept of free radical injury in various lung disorders and therefore a thought can be given to whether antioxidant supply could have a beneficial impact on the free radical induced injury and improvement of respiratory reserve in various lung disorders.

  10. Effectiveness of ascorbic acid and PVP in the rooting of clonal minicuttings of Eucalyptus urophylla x Eucalyptus grandis

    Directory of Open Access Journals (Sweden)

    Lucas Amaral de Melo

    2011-12-01

    Full Text Available The objective of this study is to evaluate the effectiveness of the antioxidants ascorbic acid and polyvinylpyrrolidone (PVP in the rooting of mini-cuttings for three clones of Eucalyptus urophylla x Eucalyptus grandis. Mini-cuttings were gathered from a mini-clonal hedge which had been cultivated in concrete ducts containing washed sand. Five concentrations of each antioxidant were experimentally tested on each of the three clones (C1, C2 and C3. Assessments were done of mini-cutting survival and rooting rates when leaving the greenhouse and the shade house, as well as seedling survival and growth at age 50 days. Ascorbic acid was found to be beneficial to the mini-cuttings of the clone with a lower rooting percentage (C3, whereas PVP was found to be unbeneficial to the clones being studied.

  11. Positron labeled antioxidants: synthesis and tissue biodistribution of 6-deoxy-6-[18F]fluoro-L-ascorbic acid

    International Nuclear Information System (INIS)

    A one-pot synthesis of 6-deoxy-6-[18F]fluoro-L-ascorbic acid (18F-DFA) has been developed via nucleophilic displacement of a cyclic sulfate with no-carrier-added [18F]fluoride ion. Isolated radiochemical yields of around 15% were obtained with radiochemical purity of over 99% after overall synthesis time of 90 min. Tissue distribution studies with 18F-DFA in rats showed high uptake of radioactivity in the adrenals, kidneys, liver and small intestine - organs known to have high concentrations of L-ascorbic acid. The slow and low uptake of radioactivity in the brain was observed between 10 and 120 min after i.v. injection. In vivo behaviour of 18F-DFA in mice bearing 3-methylcholanthrene-induced fibrosarcoma demonstrated its ability to accumulate in the tumor. (author)

  12. Production of 61Cu using natural cobalt target and its separation using ascorbic acid and common anion exchange resin

    International Nuclear Information System (INIS)

    61Cu was produced by natCo(?, xn)61Cu reaction. 61Cu production yield was 89.5 MBq/?Ah (2.42 mCi/?Ah) at the end of irradiation (EOI). A simple radiochemical separation method using anion exchange resin and ascorbic acid has been employed to separate the product radionuclide from inactive target material and co-produced non-isotopic impurities. The radiochemical separation yield was about 90%. Radiochemical purity of 61Cu was >99% 1 h after EOI. Final product was suitable for making complex with N2S2 type of ligands. - Highlights: ? High purity, no-carrier added 61Cu produced from natural cobalt target. ? 61Cu separated from impurities using anion exchange resin and ascorbic acid. ? 61Cu preparation was successfully used to label N2S2-type of ligand.

  13. Effects of the ascorbic acid supplementation on NADH-diaphorase myenteric neurons in the duodenum of diabetic rats

    Scientific Electronic Library Online (English)

    Marli Aparecida Dos Santos, Pereira; Maria Claúdia, Bagatin; Jacqueline Nelisis, Zanoni.

    2006-08-01

    Full Text Available SciELO Argentina | Language: English Abstract in english We assessed the ascorbic acid (AA) supplementation on the myenteric neurons in the duodenum of rats. Fifteen rats with 90 days of age were divided into three groups: control (C), diabetics (D) and ascorbic acid treated diabetics (DA). After 120 days of daily treatment with AA, the duodenum was submi [...] tted to the NADH-diaphorase (NADH-d) histochemical technique, which allowed us to evaluate the neuronal density in an area of 8.96 mm² for each duodenum, and also to measure the cellular profile area of 500 neurons per group. The supplementation promoted an increase on AA levels. The neuronal density (p 0.05). The AA-supplementation avoided the density reduction of the NADHd myenteric neurons in the duodenum of diabetic rats.

  14. Effects of the ascorbic acid supplementation on NADH-diaphorase myenteric neurons in the duodenum of diabetic rats

    Directory of Open Access Journals (Sweden)

    Marli Aparecida Dos Santos Pereira

    2006-08-01

    Full Text Available We assessed the ascorbic acid (AA supplementation on the myenteric neurons in the duodenum of rats. Fifteen rats with 90 days of age were divided into three groups: control (C, diabetics (D and ascorbic acid treated diabetics (DA. After 120 days of daily treatment with AA, the duodenum was submitted to the NADH-diaphorase (NADH-d histochemical technique, which allowed us to evaluate the neuronal density in an area of 8.96 mm² for each duodenum, and also to measure the cellular profile area of 500 neurons per group. The supplementation promoted an increase on AA levels. The neuronal density (p 0.05. The AA-supplementation avoided the density reduction of the NADHd myenteric neurons in the duodenum of diabetic rats.

  15. Partial molar volumes and viscosity B-coefficients of arginine in aqueous glucose, sucrose and L-ascorbic acid solutions at T = 298.15 K

    International Nuclear Information System (INIS)

    Densities and viscosities of arginine in (glucose + water), (sucrose + water) and (L-ascorbic acid + water) mixed solvents have been measured at T 298.15 K by an oscillating-tube densimeter and viscometer. Standard-state partial molar volume, hydration number and viscosity B-coefficients of arginine have been calculated. The transfer volumes from water to (sugar + water) or (L-ascorbic acid + water) mixed solvents have been obtained and discussed in terms of the structural hydration interaction model. The results indicate that the partial molar volumes of transfer and viscosity B-coefficients of arginine increase with increasing the mass concentration of sugar or L-ascorbic acid, and the hydration number of arginine decreases owing to the interaction of sugar or L-ascorbic acid and the zwitterionic groups. It is concluded that the magnitude of the enhancement effect on volume and hydration number is related to the number of OH groups and the structure of mixture solvent

  16. Catalytic formation of silver nanoparticles by bovine serum albumin protected-silver nanoclusters and its application for colorimetric detection of ascorbic acid

    Science.gov (United States)

    Yang, Xiu-Hua; Ling, Jian; Peng, Jun; Cao, Qiu-E.; Wang, Lei; Ding, Zhong-Tao; Xiong, Jie

    2013-04-01

    We established a simple spectrophotometric and colorimetric method for detection of ascorbic acid based on the growth of silver nanoparticles in bovine serum albumin protected-silver nanoclusters (BSA-AgNCs) and Ag+ mixture. Due to the catalysis of BSA-AgNCs, ascorbic acid could reduce Ag+ to silver nanoparticles (NPs) at room temperature. The color of the mixture changed from colorless to yellow and a strong absorption band near 420 nm could be found in their absorption spectra owing to localized surface plasmon resonance (LSPR) of produced silver NPs. The absorbance changes at 420 nm had a good relationship with ascorbic acid concentration. Thus, we proposed a spectrophotometric and colorimetric method to determine ascorbic acid in concentration range from 2.0 to 50.0 ?M, with the corresponding limits of determination (3?) of 0.16 ?M.

  17. A spectroscopic study on applicability of spectral analysis for simultaneous quantification of L-dopa, benserazide and ascorbic acid in batch and flow systems

    Science.gov (United States)

    Karpi?ska, Joanna; Smyk, Jerzy; Wo?yniec, El?bieta

    2005-11-01

    The usefulness of derivative spectrophotometry for simultaneous assay of L-dopa, benserazide and ascorbic acid in pharmaceuticals was studied. The parameters of derivatisation depends on composition of solution in which particular compound was determined. For quantification of L-dopa in mixtures with benserazide or ascorbic acid the first derivative was used. Its determination in ternary mixture ( L-dopa + benserazide + ascorbic acid) is possible by third derivative spectra. Benserazide was assayed in presence of L-dopa using first derivative while in ternary mixture by third derivative. Direct determination of ascorbic acid is possible applying first derivative only in presence of L-dopa. The elaborated derivative spectrophotometric methods were used for assaying of L-dopa and benserazide in their commercial form "Madopar". The proposed spectrophotometric derivative method of simultaneous determination of L-dopa and benserazide was combined with FIA technique.

  18. L-ascorbic acid determination in pharmaceutical formulations using a biosensor based on carbon paste modified with crude extract of zucchini (Cucurbita pepo

    Directory of Open Access Journals (Sweden)

    Fatibello-Filho Orlando

    2000-01-01

    Full Text Available A biosensor based on carbon paste modified with crude extract of zucchini (Cucurbita pepo as a source of peroxidase is proposed for determining L-ascorbic acid in pharmaceutical formulations. This enzyme in the presence of hydrogen peroxide catalyses the oxidation of hydroquinone to p-quinone whose electrochemical reduction back to hydroquinone was obtained at peak potential of -0.14V. Thus, when L-ascorbic acid is added to the solution, this acid can reduce chemically p-quinone to hydroquinone and/or reduce hydrogen peroxide, decreasing the peak current obtained proportionally to the increase of its concentration. The recovery of L-ascorbic acid from five samples ranged from 98.1 to 102.1% and a rectilinear calibration curve for L-ascorbic acid concentration from 2.0x10-4 to 5.5x10-3 mol L-1 (r=0.9992 was obtained. The detection limit was 2.2x10-5 mol L-1 and relative standard deviation was < 1.3% for a solution containing 4.0x10-3 mol L-1 L-ascorbic acid, 7.0x10-3 mol L-1 hydroquinone and 2.0x10-4 mol L-1 hydrogen peroxide. The results obtained for L-ascorbic acid in pharmaceutical formulations using the proposed biosensor and those obtained using the Pharmacopeia method are in agreement at the 95 % confidence level.

  19. Facile synthesis of graphene hybrid tube-like structure for simultaneous detection of ascorbic acid, dopamine, uric acid and tryptophan

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Wen [Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Chai Yaqin, E-mail: yqchai@swu.edu.cn [Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yuan Ruo, E-mail: yuanruo@swu.edu.cn [Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Chen Shihong; Han Jing; Yuan Dehua [Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

    2012-12-05

    Graphical abstract: A tube-like structure of graphene hybrid (GS-PTCA) was synthesized via {pi}-{pi} stacking interaction, and was used as modifier to fabricate electrode for simultaneous detection of ascorbic acid (AA), dopamine (DA), uric acid (UA) and tryptophan (Trp). SEM images of GS, PTCA and GS-PTCA were presented. Under the synergistic effects between GS and PTCA, the modified electrode displayed high catalytic activity and selectivity toward the oxidation of AA, DA, UA, and Trp. Highlights: Black-Right-Pointing-Pointer A simple strategy for simultaneous detection of AA, DA, UA and Trp has been constructed. Black-Right-Pointing-Pointer The tube-like structure of graphene hybrid (GS-PTCA) was synthesized. Black-Right-Pointing-Pointer The GS-PTCA provided a selective interface for discrimination of AA, DA, UA and Trp. - Abstract: In the present work, a tube-like structure of graphene hybrid as modifier to fabricate electrode for simultaneous detection of ascorbic acid (AA), dopamine (DA), uric acid (UA) and tryptophan (Trp) was reported. The hybrid was synthesized by a simple method based on graphene sheets (GS) and 3,4,9,10-perylenetetracarboxylic acid (PTCA) via {pi}-{pi} stacking interaction under ultrasonic condition. The combination of GS and PTCA could effectively improve the dispersion of GS, owing to PTCA with the carboxylic-functionalized interface. Comparing with pure GS or PTCA modified electrode, GS-PTCA displayed high catalytic activity and selectivity toward the oxidation of AA, DA, UA, and Trp. Moreover, cyclic voltammetry, different pulse voltammetry and scanning electron microscopy were employed to characterize the sensors. The experiment results showed that the linear response range for simultaneous detection of AA, DA, UA, and Trp were 20-420 {mu}M, 0.40-374 {mu}M, 4-544 {mu}M and 0.40-138 {mu}M, respectively, and the detection limits were 5.60 {mu}M, 0.13 {mu}M, 0.92 {mu}M and 0.06 {mu}M (S/N = 3). Importantly, the proposed method offers promise for simple, rapid, selective and cost-effective analysis of small biomolecules.

  20. Facile synthesis of graphene hybrid tube-like structure for simultaneous detection of ascorbic acid, dopamine, uric acid and tryptophan

    International Nuclear Information System (INIS)

    Graphical abstract: A tube-like structure of graphene hybrid (GS–PTCA) was synthesized via ?–? stacking interaction, and was used as modifier to fabricate electrode for simultaneous detection of ascorbic acid (AA), dopamine (DA), uric acid (UA) and tryptophan (Trp). SEM images of GS, PTCA and GS–PTCA were presented. Under the synergistic effects between GS and PTCA, the modified electrode displayed high catalytic activity and selectivity toward the oxidation of AA, DA, UA, and Trp. Highlights: ? A simple strategy for simultaneous detection of AA, DA, UA and Trp has been constructed. ? The tube-like structure of graphene hybrid (GS–PTCA) was synthesized. ? The GS–PTCA provided a selective interface for discrimination of AA, DA, UA and Trp. - Abstract: In the present work, a tube-like structure of graphene hybrid as modifier to fabricate electrode for simultaneous detection of ascorbic acid (AA), dopamine (DA), uric acid (UA) and tryptophan (Trp) was reported. The hybrid was synthesized by a simple method based on graphene sheets (GS) and 3,4,9,10-perylenetetracarboxylic acid (PTCA) via ?–? stacking interaction under ultrasonic condition. The combination of GS and PTCA could effectively improve the dispersion of GS, owing to PTCA with the carboxylic-functionalized interface. Comparing with pure GS or PTCA modified electrode, GS–PTCA displayed high catalytic activity and selectivity toward the oxidation of AA, DA, UA, and Trp. Moreover, cyclic volreover, cyclic voltammetry, different pulse voltammetry and scanning electron microscopy were employed to characterize the sensors. The experiment results showed that the linear response range for simultaneous detection of AA, DA, UA, and Trp were 20–420 ?M, 0.40–374 ?M, 4–544 ?M and 0.40–138 ?M, respectively, and the detection limits were 5.60 ?M, 0.13 ?M, 0.92 ?M and 0.06 ?M (S/N = 3). Importantly, the proposed method offers promise for simple, rapid, selective and cost-effective analysis of small biomolecules.

  1. Interferência do ácido ascórbico nas determinações de parâmetros bioquímicos séricos: estudos in vivo e in vitro Ascorbic acid interference on the measurement of serum biochemical parameters: in vivo and in vitro studies

    Directory of Open Access Journals (Sweden)

    Flávia Martinello

    2003-01-01

    Full Text Available INTRODUÇÃO: O ácido ascórbico, quando presente em amostras biológicas, pode interferir nos ensaios laboratoriais que utilizam reações de oxidorredução. OBJETIVOS: Estabelecer o grau de interferência do ácido ascórbico nas determinações bioquímicas séricas em relação à dose de vitamina C, ingerida e ao tempo de coleta das amostras e comparar com o efeito interferente in vitro. MÉTODOS: Voluntários saudáveis (n = 18 consumiram doses crescentes e sucessivas de 0,25 a 4g/dia de vitamina C durante uma semana cada dose. As determinações bioquímicas de ácido úrico, bilirrubina, colesterol total, glicose e triglicerídeos foram realizadas antes e 4, 12 e 24 horas após a última ingestão de cada dose. No estudo in vitro, concentrações crescentes de ácido ascórbico foram adicionadas ao soro humano e os analitos foram determinados até 24 horas após a adição. RESULTADOS E DISCUSSÃO: Os níveis séricos de ácido ascórbico aumentaram significativamente após a ingestão da vitamina C, provocando inibição nas determinações de ácido úrico e bilirrubina total 4, 12 e 24 horas após a ingestão (p BACKGROUND: Ascorbic acid, when present in biological samples, can produce a negative interference in several biochemical tests that use redox indicator systems. OBJECTIVES: We evaluated the ascorbic acid interference on serum biochemical tests in relation to the dose of vitamin C ingested and to the time of blood collection, and compared these results with in vitro interference. METHODS: Healthy volunteers (n =18 consumed increasing and successive doses of vitamin C (0.25 to 4g/day for one week. Biochemical analytes were measured before and after each dose consumption. Serum samples were obtained 4, 12 and 24 h after vitamin C ingestion. Ascorbic acid was added in vitro to the human serum and the biochemical analytes were assayed up to 24 h after addition. RESULTS AND DISCUSSION: Serum ascorbic acid increased significantly after vitamin C ingestion, inhibiting the assays for urate and total bilirubin up to 24 h after ingestion (p < 0,01. In contrast, the ingested vitamin C did not interfere on the glucose, cholesterol, and triglycerides tests. In vitro ascorbic acid inhibited the reactions for all studied tests, proportional to the ascorbic acid amount and inversely proportional to the analyte concentrations. The urate test had in vitro interference only, whereas for bilirubin there were in vitro and, mainly, in vivo interference. CONCLUSION: To avoid false-negative results of serum urate and bilirubin we recommend the suspension of vitamin C intake at least 48 horas before blood collection.

  2. The Planetary Biology of Ascorbate and Uric acid and their Relationship with the Epidemic of Obesity and Cardiovascular Disease

    OpenAIRE

    Johnson, Richard J.; Gaucher, Eric A.; Sautin, Yuri Y.; Henderson, George N.; Angerhofer, Alex J.; Benner, Steven A.

    2008-01-01

    Humans have relatively low plasma ascorbate levels and high serum uric acid levels compared to most mammals due to the presence of genetic mutations in L-gulonolactone oxidase and uricase, respectively. We review the major hypotheses for why these mutations may have occurred. In particular, we suggest that both mutations may have provided a survival advantage to early primates by helping maintain blood pressure during periods of dietary change and environmental stress. We further propose that...

  3. Ascorbic Acid Enhances the Accumulation of Polycyclic Aromatic Hydrocarbons (PAHs) in Roots of Tall Fescue (Festuca arundinacea Schreb.)

    OpenAIRE

    Gao, Yanzheng; Li, Hui; Gong, Shuaishuai

    2012-01-01

    Plant contamination by polycyclic aromatic hydrocarbons (PAHs) is crucial to food safety and human health. Enzyme inhibitors are commonly utilized in agriculture to control plant metabolism of organic components. This study revealed that the enzyme inhibitor ascorbic acid (AA) significantly reduced the activities of peroxidase (POD) and polyphenol oxidase (PPO), thus enhancing the potential risks of PAH contamination in tall fescue (Festuca arundinacea Schreb.). POD and PPO enzymes in vitro e...

  4. Plasma levels and redox status of ascorbic acid and levels of lipid peroxidation products in active and passive smokers.

    OpenAIRE

    Ayaori, M.; Hisada, T.; Suzukawa, M.; Yoshida, H.; Nishiwaki, M.; Ito, T.; Nakajima, K.; Higashi, K.; Yonemura, A.; Ohsuzu, F.; Ishikawa, T.; Nakamura, H.

    2000-01-01

    Both active and passive smoking are regarded as risk factors for various diseases. To clarify the effects of active and passive smoking on plasma vitamin C levels and lipid peroxidation status, we examined the plasma levels of ascorbic acid (AA), its redox status [ratio of dehydroascorbate (DHAA) to total AA], the levels of thiobarbiturate reactive substance (TBARS), and the levels of lipid peroxides (LPO) in smokers, nonsmokers, and nonsmokers regularly exposed to environmental cigarette smo...

  5. The content determination of calcium, magnesium and ascorbic acid in sea buckthorn fruits at vulcan coal dump

    OpenAIRE

    Brasovan, Andreea; Codrea, Vlad; Ma?ndroc, Vasilica; Ca?mpean, Ramona; Olah, Neli

    2009-01-01

    The study presents data on content determination of calcium, magnesium and ascorbic acid in sea buckthorn fruits collected from Vulcan coal dump. The dump was never covered with soil or fertilizers containing azoth, potassium and phosphorus. The sea buckthorn was planted directly on the sterile and it has an important function in stabilizing the acclivity and fixing the atmospheric azoth with the nodosities on the roots. So, the sea buckthorn becomes widespread plant in coal dumps because it ...

  6. Cheap and easy modification of glassy carbon electrode for voltammetric determination of dopamine in the presence of ascorbic acid

    OpenAIRE

    Naseri, A.; MR Majidi

    2011-01-01

    Background and the purpose of the study: Different methods have been proposed to modify glassy carbon electrode in order to determine dopamine (DA), as one of the most important neurotransmitters in central nervous systems of mammalian. These methods are time comsuming and in some cases expensive. In this work, a very simple and cheap pretreatment method is developed for the bare glassy carbon electrode (GCE) to determine DA in the presence of Ascorbic acid (AA).   Methods: Cyclic vo...

  7. Simultaneous Determination of Dopamine, Serotonin and Ascorbic Acid at a Glassy Carbon Electrode Modified with Carbon-Spheres

    OpenAIRE

    Jianqing Zhou; Meili Sheng; Xueyue Jiang; Guozhi Wu; Feng Gao

    2013-01-01

    A novel glassy carbon electrode (GCE) modified with carbon-spheres has been fabricated through a simple casting procedure. The modified GCE displays high selectivity and excellent electrochemical catalytic activities towards dopamine (DA), serotonin (5-HT), and ascorbic acid (AA). In the co-existence system, the peak separations between AA and DA, DA and 5-HT, and AA and 5-HT are large up to 230, 180, and 410 mV, respectively. Differential pulse voltammetry (DPV) has been employed to simultan...

  8. Chemically Modified Carbon Paste Electrodes for Ascorbic Acid Determination in Soft Drinks by Flow Injection Amperometric Analysis

    OpenAIRE

    Sales, M. Goreti F.; Castanheira, M. S. A.; Ferreira, Rosa M. S.; Vaz, M. Carmo V. F.; Cristina Delerue-Matos

    2008-01-01

    Simple, rapid and precise amperometric methods for quantification of ascorbic acid (AA) are presented. Glassy carbon (GC), carbon paste (CP) and modified carbon paste (MCP) electrodes are used for this purpose. MCP electrodes are of CP with 10 % vanadate (V). All electrodes are inserted in a wall-jet device with an Ag/AgCl reference electrode and a platinum auxiliary electrode. This device is coupled to a flow injection analysis (FIA) set-up. Hydrodynamic and amperometric parameters are optim...

  9. Effect of packing on changes in erythrocyte osmotic fragility and malondialdehyde concentration in donkeys administered with ascorbic acid

    OpenAIRE

    Ambali, Suleiman F.; Ayo, Joseph O.; Folashade Olaifa; Rekwot, Peter I.

    2012-01-01

    Experiments were performed with the aim of investigating the effect of packing on erythrocyte osmotic fragility (EOF) and malondialdehyde (MDA) concentration in donkeys, and the effect of ascorbic acid (AA). Twelve apparently healthy donkeys raised under the traditional extensive system served as experimental subjects. Six donkeys administered orally with AA (200 mg/kg) and subjected to packing were used as experimental animals, whilst six others not administered with AA served as controls. B...

  10. Simultaneous Determination of Dopamine and L-Ascorbic Acid by Modified Carbon Paste Electrode with Ni (II) Cyclam Complex

    OpenAIRE

    Mohammad Reza Milani Hosseini; Leila Farzin

    2011-01-01

    The electroanalysis of dopamine (DA) and ascorbic acid (AA) by square wave voltammetry has been performed at a modified carbon paste electrode with macrocyclic ligand 1, 4, 8, 11-tetraazacyclotetradecane (cyclam) and monolayer of Ni (II) cyclam. In pH 7.2 buffer solutions, the electrostatic reaction of AA with di-positive monolayer shifts the oxidation potential to less positive potential, while the electrostatic repulsion of DA with the monolayer shifts the oxidation potential of DA to more ...

  11. Selective Determination of Epinephrine in the Presence of Ascorbic Acid and Dopamine Using a Glassy Carbon Electrode Modified with Valine

    OpenAIRE

    Xia Li; Meifeng Chen; Xinying Ma; Xianjie Lin

    2010-01-01

    A glassy carbon electrode (GCE) modified with valine was used for the sensitive volt metric determination ofepinephrine (EP). The electrochemical response characteristics of the modified electrode toward EP, ascorbic acid (AA)and dopamine (DA) were investigated by cyclic voltammetry (CV). The results show an efficient catalytic activity ofthe electrode for the electro-oxidation of EP, which leads to an improvement to the reversibility of the electroderesponse. The effect of pH and potential s...

  12. Effect of ascorbic acid supplementation on nitric oxide metabolites and systolic blood pressure in rats exposed to lead

    OpenAIRE

    Mohammad Amani; Ali Noroozzadeh; Reza Badalzadeh; Ali Khoshbaten

    2010-01-01

    Background: Extended exposure to low levels of lead causes high blood pressure in human and laboratory animals. The mechanism is not completely recognized, but it is relatively implicated with generation of free radicals, oxidant agents such as ROS, and decrease of available nitric oxide (NO). In this study, we have demonstrated the effect of ascorbic acid as an antioxidant on nitric oxide metabolites and systolic blood pressure in rats exposed to low levels of lead. Materials and Methods:...

  13. Ascorbic acid for the healing of skin wounds in rats Ácido ascórbico na cicatrização de feridas cutâneas em ratos

    OpenAIRE

    Cc, Lima; Apc, Pereira; Jrf, Silva; Ls, Oliveira; Mcc, Resck; Co, Grechi; Mtcp, Bernardes; Fmp, Oli?mpio; Amm, Santos; Ek, Incerpi; Jad, Garcia

    2009-01-01

    BACKGROUND: Healing is a complex process that involves cellular and biochemical events. Several medicines have been used in order to shorten healing time and avoid aesthetic damage. OBJECTIVE: to verify the topical effect of ascorbic acid for the healing of rats' skin wounds through the number of macrophages, new vessels and fibroblast verifications in the experimental period; and analyse the thickness and the collagen fibre organization in the injured tissue. METHODS: Male Rattus norvegicus ...

  14. The ascorbic acid content of tomato fruits is associated with the expression of genes involved in pectin degradation

    OpenAIRE

    Di Matteo Antonio; Sacco Adriana; Anacleria Milena; Pezzotti Mario; Delledonne Massimo; Ferrarini Alberto; Frusciante Luigi; Barone Amalia

    2010-01-01

    Abstract Background High levels of ascorbic acid (AsA) in tomato fruits provide health benefits for humans and also play an important role in several aspects of plant life. Although AsA metabolism has been characterized in detail, the genetic mechanisms controlling AsA accumulation in tomatoes are poorly understood. The transcriptional control of AsA levels in fruits can be investigated by combining the advanced genetic and genomic resources currently available for tomato. A comparative trans...

  15. A self-seeding synthesis of Ag microrods of tuned aspect ratio: ascorbic acid plays a key role

    International Nuclear Information System (INIS)

    Control of the shape and size of nanoparticles is crucial for using them as labels or as building blocks in nanotechnology. In fact, silver has so far been considered as having the widest variety of different morphologies at the nano-scale and micro-scale levels. To make progress in these criteria, in our paper we have synthesized highly reproducible silver (Ag) microrods of controlled aspect ratios through a rapid self-seeding method. The Ag nano seeds are formed via the reduction of Ag ions in hot ethylene glycol by ascorbic acid, and the subsequent growth of microrods is controlled by further deposition of Ag atoms in the presence of poly(vinylpyrrolidone). Moreover, ascorbic acid is exclusively responsible for the rod morphology, as we describe here in detail. A very low concentration of ascorbic acid forms very few Ag microrods along with a majority of Ag colloidal particles, while random overgrowth on the surfaces is observed for higher concentrations. The critical reaction condition has been found in that the aspect ratio of the Ag microrods can be systematically tuned between 4 and 90. Also, the method in which ascorbic acid is added to the reaction medium plays a key role in controlling the aspect ratio of the Ag microrods. The non-monotonic dependence of the length and the diameter of the Ag microrods has been described by an empirical equation. The function can be interpreted by means of concentration-dependent competition between the adsorption of ligands etition between the adsorption of ligands and metal deposition. (paper)

  16. Effect of ascorbic acid on thyroid functions and some biochemical activities in rats treated with cadmium chloride

    International Nuclear Information System (INIS)

    This study was carried out to investigate the role of oral administration of ascorbic acid (vitamin C) in rats at a dose level of 100 mg/kg body weight in reducing disturbances caused by cadmium at a dose level of 1.2 mg CdCl2/Kg body weight (1/4 LD50). Cadmium treatment induced thyroid dysfunction and disturbance in blood count and some elements in sera of male rats. The rats were divided into four groups. The first group (I) of rats served as normal control, the second group (II) was treated with CdCl2, the third group (III) was treated with CdCl2 followed by 2 weeks rehabilitation and the fourth one (IV) was treated with CdCl2 followed by ascorbic acid treatment. Serum total T3, total T4, hemoglobin, red blood cell count, and hematocrit value, blood indices as well as white blood cell count, total serum calcium, phosphorus and alkaline phosphatase were evaluated in all rats.The results revealed that treatment with cadmium in groups II and III led to significant decreases in T3 and T4 levels and most of blood count parameters.In rats treated with ascorbic acid, a non-significant improvement in serum T3 level was obtained, whereas, serum T4 level was significantly increased and its level was reached around corresponding control value. Also, ascorbic acid treatment led to significant increases in Hb, RBCs, Hct, MCV, MCH and MCHC values, which were comparable to those obtained in control, whereas WBCs count was slined in control, whereas WBCs count was slightly improved in group (IV) in comparison with both groups treated with Cd but it was highly significantly decreased in both groups treated with Cd as compared to control. Serum total calcium and alkaline phosphatase activity were non-significantly decreased, whereas inorganic phosphorus concentrations was significantly decreased in groups III and IV as compared to control

  17. Ascorbic Acid Biosynthesis and Brackish Water Acclimation in the Euryhaline Freshwater White-Rimmed Stingray, Himantura signifer

    OpenAIRE

    Wong, Samuel Z. H.; Ching, Biyun; Chng, You R.; Wong, Wai P.; Chew, Shit F.; Ip, Yuen K.

    2013-01-01

    L-gulono-?-lactone oxidase (Gulo) catalyzes the last step of ascorbic acid biosynthesis, which occurs in the kidney of elasmobranchs. This study aimed to clone and sequence gulonolactone oxidase (gulo) from the kidney of the euryhaline freshwater stingray, Himantura signifer, and to determine the effects of acclimation from freshwater to brackish water (salinity 20) on its renal gulo mRNA expression and Gulo activity. We also examined the effects of brackish water acclimation on concentratio...

  18. Glassy carbon electrodes modified with multiwalled carbon nanotubes for the determination of ascorbic acid by square-wave voltammetry

    Directory of Open Access Journals (Sweden)

    Sushil Kumar

    2012-05-01

    Full Text Available Multiwalled carbon nanotubes were used to modify the surface of a glassy carbon electrode to enhance its electroactivity. Nafion served to immobilise the carbon nanotubes on the electrode surface. The modified electrode was used to develop an analytical method for the analysis of ascorbic acid (AA by square-wave voltammetry (SWV. The oxidation of ascorbic acid at the modified glassy carbon electrode showed a peak potential at 315 mV, about 80 mV lower than that observed at the bare (unmodified electrode. The peak current was about threefold higher than the response at the bare electrode. Replicate measurements of peak currents showed good precision (3% rsd. Peak currents increased with increasing ascorbic acid concentration (dynamic range = 0.0047–5.0 mmol/L and displayed good linearity (R2 = 0.994. The limit of detection was 1.4 ?mol/L AA, while the limit of quantitation was 4.7 ?mol/L AA. The modified electrode was applied to the determination of the amount of ascorbic acid in four brands of commercial orange-juice products. The measured content agreed well (96–104% with the product label claim for all brands tested. Recovery tests on spiked samples of orange juice showed good recovery (99–104%. The reliability of the SWV method was validated by conducting parallel experiments based on high-performance liquid chromatography (HPLC with absorbance detection. The observed mean AA contents of the commercial orange juice samples obtained by the two methods were compared statistically and were found to have no significant difference (P = 0.05.

  19. Evaluation of the genotype, environment and their interaction on carotenoid and ascorbic acid accumulation in tomato germplasm

    OpenAIRE

    Rosello? Ripolle?s, Salvador; Adalid, Ana Mari?a; Cebolla Cornejo, Jaime; Nuez Vin?als, Fernando

    2011-01-01

    BACKGROUND: Tomatoes are an important source of antioxidants (carotenoids, vitamin C, etc.) owing to their high level of consumption. There is great interest in developing cultivars with increased levels of lycopene, ?-carotene or L-ascorbic acid. There is necessary to survey new sources of variation. In this study, the potential of improvement for each character in tomato breeding programmes, in a single or joint approach, and the nature of genotype (G), environment (E) and G × E interacti...

  20. Redox Cycles of Caffeic Acid, alpha-Tocopherol, and Ascorbate: Implications for Protection of Low-Density Lipoproteins Against Oxidation

    OpenAIRE

    Laranjinha, Joa?o; Cadenas, Enrique

    1999-01-01

    This study addresses the dynamic interactions among alpha-tocopherol, caffeic acid, and ascorbate in terms of a sequence of redox cycles aimed at accomplishing optimal synergistic antioxidant protection. Several experimental models were designed to examine these interactions: UV irradiation of alpha-tocopherol-containing sodium dodecyl sulfate micelles, one-electron oxidations catalyzed by the hypervalent state of myoglobin, ferrylmyoglobin, and autoxidation at appropriate pHs. These models w...

  1. Simultaneous/Selective Detection of Dopamine and Ascorbic Acid at Synthetic Zeolite-Modified/Graphite-Epoxy Composite Macro/Quasi-Microelectrodes

    OpenAIRE

    Rodica Pode; Elida Cristina Ilinoiu; Pier Andrea Serra; Florica Manea

    2013-01-01

    The present paper aims to miniaturize a graphite-epoxy and synthetic zeolite-modified graphite-epoxy composite macroelectrode as a quasi-microelectrode aiming in vitro and also, envisaging in vivo simultaneous electrochemical detection of dopamine (DA) and ascorbic acid (AA) neurotransmitters, or DA detection in the presence of AA. The electrochemical behavior and the response of the designed materials to the presence of dopamine and ascorbic acid without any protective membranes were studied...

  2. EVALUATION OF ANTIPEROXIDATIVE POTENTIAL OF ASCORBIC ACID ON BUSULFAN-INDUCED LIPID PEROXIDATION USING 4-HYDROXY-2-NONENAL AND NITRIC OXIDE AS MODEL MARKERS

    OpenAIRE

    Supratim Ray

    2012-01-01

    The study was designed with an aim to evaluate the antiperoxidative potential of ascorbic acid on busulfan-induced lipid peroxidation. The study was performed in vitro using goat liver as lipid source. This evaluation was done by measuring the 4-hydroxy-2-nonenal (4-HNE) and nitric oxide (NO) content of liver tissue homogenates as markers of lipid peroxidation. The study reveals the lipid peroxidation induction capacity of busulfan and the antiperoxidative potential of ascorbic acid on busulf...

  3. Elimination of ascorbic Acid after high-dose infusion in prostate cancer patients: a pharmacokinetic evaluation.

    Science.gov (United States)

    Nielsen, Torben K; Højgaard, Martin; Andersen, Jon T; Poulsen, Henrik E; Lykkesfeldt, Jens; Mikines, Kári J

    2015-04-01

    Treatment with high-dose intravenous (IV) ascorbic acid (AA) is used in complementary and alternative medicine for various conditions including cancer. Cytotoxicity to cancer cell lines has been observed with millimolar concentrations of AA. Little is known about the pharmacokinetics of high-dose IV AA. The purpose of this study was to assess the basic kinetic variables in human beings over a relevant AA dosing interval for proper design of future clinical trials. Ten patients with metastatic prostate cancer were treated for 4 weeks with fixed AA doses of 5, 30 and 60 g. AA was measured consecutively in plasma and indicated first-order elimination kinetics throughout the dosing range with supra-physiological concentrations. The target dose of 60 g AA IV produced a peak plasma AA concentration of 20.3 mM. Elimination half-life was 1.87 hr (mean, S.D. ± 0.40), volume of distribution 0.19 L/kg (S.D. ±0.05) and clearance rate 6.02 L/hr (100 mL/min). No differences in pharmacokinetic parameters were observed between weeks/doses. A relatively fast first-order elimination with half-life of about 2 hr makes it impossible to maintain AA concentrations in the potential cytotoxic range after infusion stop in prostate cancer patients with normal kidney function. We propose a regimen with a bolus loading followed by a maintenance infusion based on the calculated clearance. PMID:25220574

  4. Effects of ascorbic acid on iproniazid-induced hepatitis in phenobarbital-treated rats.

    Science.gov (United States)

    Matsuki, Y; Bandou, R; Kiwada, H; Maeda, H; Goromaru, T

    1994-08-01

    The effects of ascorbic acid (AA) on hepatic injury induced by iproniazid (IPN) in phenobarbital-treated rats were investigated by the evaluation of hepatic function using the clearance of aminopyrine (AM). Either IPN or isopropylhydrazine (IP-Hy), a potent toxic metabolite of IPN, were administered as a pretreatment to rats with or without AA. After i.v. injection of AM, the blood concentration of AM was determined by capillary gas chromatography by isotope dilution analysis using deuterium-labeled AM (AM-d9) as the internal standard. The kinetic parameters of AM, Vd, kel and total body clearance, were estimated from the time course of blood concentration. Pretreatment with IPN with AA led to a marked increase in the kel and in the clearance compared with pretreatment using IPN alone. A significant increase in the kel and the clearance was also found in the case of combined pretreatment using IP-Hy with AA. The effects of AA on the hepatic injury induced by IPN were studied according to its histological aspects. In the specimens obtained following the administration of IPN or IP-Hy with AA, the degree of cell necrosis was remarkably lowed both quantitatively and qualitatively. The present results clearly demonstrate that AA was effective in reducing IPN-induced hepatitis. PMID:7820112

  5. Melatonin combined with ascorbic acid provides salt adaptation in Citrus aurantium L. seedlings.

    Science.gov (United States)

    Kostopoulou, Zacharoula; Therios, Ioannis; Roumeliotis, Efstathios; Kanellis, Angelos K; Molassiotis, Athanassios

    2015-01-01

    Ascorbic acid (AsA) and melatonin (Mel) are known molecules participating in stress resistance, however, their combined role in counteracting the impact of salinity in plants is still unknown. In this work the effect of exogenous application of 0.50 m? AsA, 1 ?? Mel and their combination (AsA + Mel) on various stress responses in leaves and roots of Citrus aurantium L. seedlings grown under 100 m? NaCl for 30 days was investigated. Application of AsA, Mel or AsA + Mel to saline solution decreased NaCl-induced electrolyte leakage and lipid peroxidation and prevented NaCl-associated toxicity symptoms and pigments degradation. Also, leaves exposed to combined AsA + Mel treatment displayed lower Cl(-) accumulation. Treatments with AsA and/or Mel modulated differently carbohydrates, proline, phenols, glutathione and the total antioxidant power of tissues as well as the activities of SOD, APX, POD, GR and PPO compared to NaCl alone treatment. Exposure of leaves and roots to chemical treatments and especially to combined AsA and Mel application was able to regulate CaMIPS, CaSLAH1 and CaMYB73 expression, indicating that sugar metabolism, ion homeostasis and transcription regulation were triggered by AsA and Mel. These results provide evidence that the activation of the metabolic pathways associated with combined AsA and Mel application are linked with salt adaptation in citrus plants. PMID:25500452

  6. Effects of Socio demographic factors on plasma ascorbic acid and alpha tocopherol anti oxidants during pregnancy

    International Nuclear Information System (INIS)

    Objectives: To assess the plasma levels of vitamins C and E at the various stages of pregnancy and to correlate their plasma levels with the socio-demographic factors of pregnant Nigerians. Methodology: The pregnant cases (n=180) were randomly selected according to gestational ages. And the controls (n=20) were non-pregnant women of the same age. Plasma levels of both vitamins were assayed with well established laboratory methods. Results: The mean plasma vitamins C and E in the pregnant cases was lower (by 17-23%) than controls across the three trimesters, p<0.0001. The correlation of vitamin C versus maternal age was significant; r = - 0.59, p<0.05; the mean plasma level of vitamin C declined by 57% as the maternal age increases from 22-37 years. Conclusion: The mean plasma Ascorbic acid and Alpha-tocopherol are reduced during pregnancy and socio-demographic factors have mild effects on the plasma levels of these vitamins. (author)

  7. Cupric oxide nanowires assembled by nanoparticles in situ with enhancing electrocatalytic oxidation of ascorbic acid

    Science.gov (United States)

    Wang, Chuanxi; Liu, Jie; Huang, Xing; Wang, Huanhuan; Zheng, Youdan; Lin, Li; Wang, Siyu; Chen, Song; Jin, Yong

    2014-02-01

    CuO nanowires are facilely fabricated on the surface of AgCuZn alloy in situ by direct oxidation and partial reduction procedures, which shows an improved electrocatalytic activity toward ascorbic acid oxidation. The morphology shows the nanowires are assembled by CuO nanoparticles and we consider the process that the unordered spheres convert to ordered wires is due to the reduction of [1 1 0] and [ 1 bar ?? 1 ?? 1 ] crystal planes in CuO. Moreover, the prepared modified electrode displays a high sensitivity of 1660 ?A cm-2 mM-1, wide linear range from 0.1 ?M to 3.1 mM and a low detection limit of 0.095 ?mol (signal/noise = 3). Further, the sensor is also tested for anti-interferences and real samples determination, exhibiting distinguished selectivity, accuracy, and recovery. Such excellent properties are owing to the special structure of the synthesized CuO that would provide more specific surface area and enhanced activity compared with common nanowires. Hence, this work of fabricating CuO nanowires assembled by CuO nanoparticles with high performance might supply a way for facile obtain more electrochemical sensor in this structure.

  8. Polyethyleneimine-templated copper nanoclusters via ascorbic acid reduction approach as ferric ion sensor.

    Science.gov (United States)

    Feng, Jie; Ju, Yuyun; Liu, Juanjuan; Zhang, Huige; Chen, Xingguo

    2015-01-01

    In this report we reported a facile one-pot method for synthesis of water-soluble and stable fluorescent CuNCs at room temperature, in which branched polyethyleneimine (BPEI) served as capping scaffold and ascorbic acid as reducing agent. The prepared BPEI-CuNCs exhibited excellent properties such as good water-solubility, photostability and high stability toward high ionic strength. Based on the electron transfer induced fluorescence quenching mechanism, this fluorescence probe was used for the sensitive and selective determination of ferric ions (Fe(3+)) in aqueous solution. The limit of detection was 340 nM in the linear range of 0.5-1000 ?M, which was lower than the maximum level of Fe(3+) permitted in drinking water by the U.S. Environmental Protection Agency. The method was successfully applied to the detection of Fe(3+) in tap water, Yellow River water and human urine samples with the quantitative spike recoveries ranging from 95.3% to 112.0%. PMID:25479879

  9. Synthesis of Au/Graphene Oxide Composites for Selective and Sensitive Electrochemical Detection of Ascorbic Acid

    Science.gov (United States)

    Song, Jian; Xu, Lin; Xing, Ruiqing; Li, Qingling; Zhou, Chunyang; Liu, Dali; Song, Hongwei

    2014-12-01

    In this work, we present a novel ascorbic acid (AA) sensor applied to the detection of AA in human sera and pharmaceuticals. A series of Au nanoparticles (NPs) and graphene oxide sheets (Au NP/GO) composites were successfully synthesized by reduction of gold (III) using sodium citrate. Then the Au NP/GO composites were used to construct nonenzymatic electrodes in practical AA measurement. The electrode that has the best performance presents attractive analytical features, such as a low working potential of +0.15 V, a high sensitivity of 101.86 ?A mM-1 cm-2 to AA, a low detection limit of 100 nM, good reproducibility and excellent selectivity. And more,it was also employed to accurately and practically detect AA in human serum and clinical vitamin C tablet with the existence of some food additive. The enhanced AA electrochemical properties of the Au NP/GO modified electrode in our work can be attributed to the improvement of electroactive surface area of Au NPs and the synergistic effect from the combination of Au NPs and GO sheets. This work shows that the Au NP/GO/GCEs hold the prospect for sensitive and selective determination of AA in practical clinical application.

  10. Simultaneous Chronoamperometric Sensing of Ascorbic Acid and Acetaminophen at a Boron-Doped Diamond Electrode

    Directory of Open Access Journals (Sweden)

    Ciprian Radovan

    2008-06-01

    Full Text Available Cyclic voltammetry (CV and chronoamperometry (CA have been used to sense and determine simultaneously L-ascorbic acid (AA and acetaminophen (AC at a boron-doped diamond electrode (BDDE in a Britton-Robinson buffer solution. The calibration plots of anodic current peak versus concentration obtained from CV and CA data for both investigated compounds in single and di-component solutions over the concentration range 0.01 mM – 0.1 mM proved to be linear, with very good correlation parameters. Sensitivity values and RSD of 2-3% were obtained for various situations, involving both individual and simultaneous presence of AA and AC. The chronoamperometric technique associated with standard addition in sequential one step and/or two successive and continuous chronoamperograms at two characteristic potential levels represented a feasible option for the simultaneous determination of AA and AC in real sample systems such as pharmaceutical formulations. The average values indicated by the supplier were confirmed to a very close approximation from chronoamperomgrams by using several additions with the application of suitable current correction factors.

  11. SCREEN-PRINTED ELECTRODE MODIFIED WITH SILVER HEXACY ANOFERRATE-NAFION® FOR ASCORBIC ACID DETERMINATION

    Scientific Electronic Library Online (English)

    I.L, MATTOS; F, PADILLA; J. H, ZAGAL; E.H.L, FALCAO; R, SEGURA.

    Full Text Available SciELO Chile | Language: English Abstract in english A flow injection system using a new and/or re-used graphite screen-printed electrode modified with silver hexacyanoferrate and a Nafion® polymer layer (AgHCF/GSPE) was employed for the determination of ascorbic acid in orange juice and drugs samples. Both modified electrodes showed an initial sensit [...] ivity of 0.015 A.cm²?.M¹?, with a linear response over the range from 50 to 300 mg L¹ , relative standard deviations smaller than 2%, detection and quantification limits of c.a. 5.0 and 25.0 mg.L¹. The response of the electrodes was stable, with no variation of base line after 6-8 hours of continuous operation. With this system it is possible to measure 65-70 samples (20??) per hour. By using 1.06 mg of AgNO3, 4.12 mg of K3Fe(CN)6, 50.5 mg of KNO3 and 800?L of HNO3, it is possible to obtain between 25 and 30 modified electrodes. The proposed system showed to be inexpensive, versatile, robust and suitable for industrial application. The surface morphology of the bare and/or modified graphite screen-printed electrode was characterized by scanning electron microscopy.

  12. A new electrochemical aptasensor based on electrocatalytic property of graphene toward ascorbic acid oxidation.

    Science.gov (United States)

    Wu, Liang; Xiong, Erhu; Yao, Yue; Zhang, Xia; Zhang, Xiaohua; Chen, Jinhua

    2015-03-01

    Based on the superior electrocatalytic property of graphene (GN) toward ascorbic acid (AA) oxidation, a new electrochemical aptasensor has been developed. Here, adenosine triphosphate (ATP) is used as the model to demonstrate the performance of the developed aptasensor. Briefly, GN is attached to the thiolated ATP binding aptamer (ABA) modified gold electrode through ?-? stacking interaction, resulting in a significant oxidation signal of AA. In the presence of ATP, the formation of ATP-ABA complex leads to the release of GN from sensing interface, resulting in a sharp decrease of the oxidation peak current of AA and an obviously positive shift of the related peak potential. Taking both the change values of the peak current and peak potential of AA oxidation as the response signals, ATP can be detected sensitively. This is the first time to demonstrate the application of GN as the nanocatalyst in an amplified aptasensor. It can be expected that GN, as nanocatalyst, should become the very promising amplifying-elements in DNA-based electrochemical biosensors. PMID:25618724

  13. Elimination of Ascorbic Acid After High-Dose Infusion in Prostate Cancer Patients: A Pharmacokinetic Evaluation

    DEFF Research Database (Denmark)

    Nielsen, Torben K; HØjgaard, Martin

    2015-01-01

    Treatment with high-dose intravenous (IV) ascorbic acid (AA) is used in complementary and alternative medicine for various conditions including cancer. Cytotoxicity to cancer cell lines has been observed with millimolar concentrations of AA. Little is known about the pharmacokinetics of high dose IV AA. The purpose of the present study was to assess the basic kinetic variables in human beings over a relevant AA dosing interval for proper design of future clinical trials. Ten patients with metastatic prostate cancer were treated for four weeks with fixed AA doses of 5, 30 and 60 g. AA was measured consecutively in plasma and indicated first-order elimination kinetics throughout the dosing range with supra-physiological concentrations. The target dose of 60g AA IV produced a peak plasma AA concentration of 20.3 mM. Elimination half-life was 1.87 hr (mean, SD ± 0.40), volume of distribution 0.19 L/kg (SD ±0.05) and clearance rate 6.02 L/hr (100mL/min). No differences in pharmacokinetic parameters were observed between weeks/doses. A relatively fast first-order elimination with half-life of about 2 hr makes it impossible to maintain AA concentrations in the potential cytotoxic range after infusion stop in prostate cancer patients with normal kidney function. We propose a regimen with a bolus loading followed by a maintenance infusion based on the calculated clearance. This article is protected by copyright. All rights reserved.

  14. Elimination of ascorbic acid after high-dose infusion in prostate cancer patients : a pharmacokinetic evaluation

    DEFF Research Database (Denmark)

    Nielsen, Torben Kjær; HØjgaard, Martin

    2015-01-01

    Treatment with high-dose intravenous (IV) ascorbic acid (AA) is used in complementary and alternative medicine for various conditions including cancer. Cytotoxicity to cancer cell lines has been observed with millimolar concentrations of AA. Little is known about the pharmacokinetics of high dose IV AA. The purpose of the present study was to assess the basic kinetic variables in human beings over a relevant AA dosing interval for proper design of future clinical trials. Ten patients with metastatic prostate cancer were treated for four weeks with fixed AA doses of 5, 30 and 60 g. AA was measured consecutively in plasma and indicated first-order elimination kinetics throughout the dosing range with supra-physiological concentrations. The target dose of 60g AA IV produced a peak plasma AA concentration of 20.3 mM. Elimination half-life was 1.87 hr (mean, SD ± 0.40), volume of distribution 0.19 L/kg (SD ±0.05) and clearance rate 6.02 L/hr (100mL/min). No differences in pharmacokinetic parameters were observed between weeks/doses. A relatively fast first-order elimination with half-life of about 2 hr makes it impossible to maintain AA concentrations in the potential cytotoxic range after infusion stop in prostate cancer patients with normal kidney function. We propose a regimen with a bolus loading followed by a maintenance infusion based on the calculated clearance. This article is protected by copyright. All rights reserved.

  15. Application of some chemometric methods in conventional and derivative spectrophotometric analysis of acetaminophen and ascorbic acid.

    Science.gov (United States)

    Khajehsharifi, H; Eskandari, Z; Asadipour, A

    2010-04-01

    The multivariate methods, principal component regression (PCR) and partial least squares (PLS) were tested as a calibration procedure for simultaneous ultraviolet spectrophotometric determination of acetaminophen (AC) and ascorbic acid (AA). Determination of these compounds is important because of their pharmacotherapeutic advantages. Due to spectral overlapping of AC and AA, PCR and PLS were used for construction of the calibration sets. The concentration linear range of AC and AA were 1.5-24.2 and 1.8-21.1 microg mL(-1) respectively. The absorption spectra were recorded from 215-310 nm. The minimum root mean square error of prediction (RMSEP) was 1.3507 and 0.4088 for AC and AA, by PLS, 0.7525 and 0.4015 by PCR in original data and 0.9454 and 0.2875, by PLS and 1.0386 and 0.4000 by PCR in derivative data. The procedure allows the simultaneous determination of AC and AA in synthetic mixtures and real sample solutions made up from pharmaceutical products, human serum and urine. PMID:20376831

  16. Electrocatalytic oxidation of ascorbic acid on a lithium-doped tantalum oxide film coated electrode

    International Nuclear Information System (INIS)

    In this work, lithium-doped tantalum oxide (lithium-Ta2O5) particles were synthesized using a low-temperature hydrothermal method. X-ray photoelectron spectroscopy (XPS) indicated that the state of lithium on the Ta2O5 surface is the Li+ form. The crystal phase of the samples was analyzed using X-ray diffraction (XRD). The analysis revealed that the lithium-Ta2O5 particles are well crystallized into an orthorhombic phase. Calculation from density functional theory (DFT) indicated that the band gap of Ta2O5 narrows when it is doped with lithium, resulting in improved conductivity and electrocatalytic activity over Ta2O5. The electrocatalytic activity of a lithium-Ta2O5 film coated electrode was investigated in a 0.1 mol dm?3 KCl solution containing ascorbic acid (AA) using cyclic voltammetry (CV). The lithium-Ta2O5 film coated electrode has excellent electrocatalytic activity toward the oxidation of AA with much reduced overpotential. The anodic peak potential of AA shifted from 0.72 V (versus Ag|AgCl) on a bare glassy carbon electrode (GCE) to 0.42 V on the lithium-Ta2O5 film coated electrode

  17. Evaluation of accelerated UV and thermal testing for benzene formation in beverages containing benzoate and ascorbic acid.

    Science.gov (United States)

    Nyman, Patricia J; Wamer, Wayne G; Begley, Timothy H; Diachenko, Gregory W; Perfetti, Gracia A

    2010-04-01

    Under certain conditions, benzene can form in beverages containing benzoic and ascorbic acids. The American Beverage Assn. (ABA) has published guidelines to help manufacturers mitigate benzene formation in beverages. These guidelines recommend accelerated testing conditions to test product formulations, because exposure to ultraviolet (UV) light and elevated temperature over the shelf life of the beverage may result in benzene formation in products containing benzoic and ascorbic acids. In this study, the effects of UVA exposure on benzene formation were determined. Benzene formation was examined for samples contained in UV stabilized and non-UV stabilized packaging. Additionally, the usefulness of accelerated thermal testing to simulate end of shelf-life benzene formation was evaluated for samples containing either benzoic or ascorbic acid, or both. The 24 h studies showed that under intense UVA light benzene levels increased by as much as 53% in model solutions stored in non-UV stabilized bottles, whereas the use of UV stabilized polyethylene terephthalate bottles reduced benzene formation by about 13% relative to the non-UV stabilized bottles. Similar trends were observed for the 7 d study. Retail beverages and positive and negative controls were used to study the accelerated thermal testing conditions. The amount of benzene found in the positive controls and cranberry juice suggests that testing at 40 degrees C for 14 d may more reliably simulate end of shelf-life benzene formation in beverages. Except for cranberry juice, retail beverages were not found to contain detectable amounts of benzene (shelf lives. PMID:20492277

  18. Effect of ascorbic acid on bond strength between the hydrogen peroxide-treated fiber posts and composite resin cores

    Science.gov (United States)

    Talebian, Reza; Khamverdi, Zahra; Nouri, Maryam; Kasraei, Shahin

    2014-01-01

    Aim: This study evaluated the effect of 10% ascorbic acid on the bond strength between fiber post and composite resin core after applying 24% hydrogen peroxide. Materials and Methods: Twenty-four hydrogen peroxide-treated fiber posts were divided into 4 groups (n = 6). Group 1 was the control group with no treatment. In groups 2-4, post surfaces were treated with 10% v ascorbic acid solution for 10, 30 and 60 minutes, respectively. Cores were built up using flowable composite resin. Two sticks were prepared from each specimen. Microtensile bond strength test was performed for each stick. Failure modes of sticks were evaluated under a stereomicroscope (×20). Surface morphologies of two fractured sticks from each group were assessed by SEM. Statistical analysis: Data were analyzed using one-way ANOVA and Tukey HSD tests (? = 0.05). Results: The highest microtensile bond strength was observed in Group 4 (20.55 ± 2.09) and the lowest in Group 1 (10.10 ± 0.55). There were significant differences in microtensile bond strength between all the groups (P < 0.05). Conclusion: It is concluded that ascorbic acid application increased the microtensile bond strength between the hydrogen peroxide treated fiber post and composite resin core. The increase is dependent on the duration of exposure to the antioxidant. PMID:24944443

  19. Influence of dried Hokkaido pumpkin and ascorbic acid addition on chemical properties and colour of corn extrudates.

    Science.gov (United States)

    Obradovi?, Valentina; Babi?, Jurislav; Šubari?, Drago; Jozinovi?, Antun; A?kar, ?ur?ica; Klari?, Ilija

    2015-09-15

    The influence of Hokkaido pumpkin powder (PP) addition to corn grits at levels 4%, 6%, and 8% and ascorbic acid (AA) addition at levels 0.5% and 1% was evaluated. Extrusion was done using a single-screw extruder at two temperature regimes: 135/170/170°C (E1) and 100/150/150°C (E2). Mathematical models that describe the influence of additives on the colour of extrudates were determined. Raw extrusion mixtures as well as obtained extrudates were tested for ascorbic acid, polyphenol, proteins, fat, crude fibre, ash and carotenoids content, and antioxidant activity. E1 extrusion regime acted favourably on polyphenols, crude fibre content, and antioxidant activity. It also caused higher fat degradation than E2 extrusion. Xanthophylls (lutein and zeaxanthin) were less sensitive to extrusion than carotenes (?-carotene, 9-cis-?-carotene and 13-cis-?-carotene). Ascorbic acid was more sensitive to higher extrusion temperatures (49-76% degradation). It provided protection to carotenoids and consequently the colour of the extrudates. PMID:25863621

  20. Selective complexometric determination of titanium(IV) using sodium potassium tartrate or ascorbic acid as masking agent

    International Nuclear Information System (INIS)

    A simple, rapid and accurate complexometric method is proposed for the determination of titanium(IV) where sodium potassium tartrate or ascorbic acid were used as masking agents. In the presence of diverse metal ions, titanium is first complexed with excess of EDTA and surplus EDTA is then titrated at pH 5-6 with zinc sulfate, xylenol orange being used as indicator. An excess of 5 % aqueous sodium potassium tartrate is then added to displace the complexed EDTA from the Ti-EDTA complex quantitatively, which is titrated with zinc sulfate. Also, ascorbic acid may be used as the releasing agent. The methods work well in the range 1-53 mg of Ti(IV) for sodium potassium tartrate with relative errors ± 0.28 % and standard deviations 0.16 mg. For ascorbic acid the range is 1.00-30.00 mg of Ti(IV) with relative errors of ± 0.40 % and standard deviations of 0.05 mg. (author)

  1. Dietary ascorbic acid normalizes ribosomal efficiency for collagen production in skin of streptozotocin-induced diabetic rats

    International Nuclear Information System (INIS)

    The objective of this study was to quantify the contribution of both ribosome amount and ribosomal efficiency to decreased collagen production in skin of diabetic rats and diabetic rats treated with dietary ascorbic acid. Male Sprague-Dawley rats were distributed equally into the following categories: non-diabetic controls; diabetics; ascorbic acid-treated diabetics. On day-20, all rats were injected with (3H)proline and killed after 2 h. Absolute rate of collagen production, ribosome content, and ribosomal efficiency of collagen production were quantified. Also ribosomal efficiency was quantified for ribosomes in sucrose-gradient fractionated post-mitochondrial supernatants. The results indicate that decreased ribosomal efficiency was responsible for 70% of the decreased collagen production with 30% caused by decreased ribosome content, when measured for total skin or sucrose gradient-isolated ribosomes. At both levels of analysis, ascorbic acid treatment normalized ribosomal efficiency, indicating diabetes-mediated decreased ribosomal efficiency for collagen production is related to a co-translational event, such as procollagen underhydroxylation

  2. Effects of ascorbic acid and alpha tocopherol supplementation on basal testosterone cortisol ratio in male sprague dawley rats

    International Nuclear Information System (INIS)

    Background: Basal testosterone cortisol ratio is considered very important to maintain homeostasis. Increase in this ratio has various beneficial effects on body. In this study we determined the effects of ascorbic acid and alpha tocopherol supplementation on basal testosterone cortisol ratio in male Sprague Dawley rats. Methods: It was quasi experimental study carried out in department of Physiology, Army Medical College Rawalpindi in collaboration with National Institute of Health, Islamabad during October 2006 to September 2007. Forty male Sprague Dawley rats were divided into four groups with ten rats in each group and above mentioned antioxidants supplementation were given along with standard diet for one month. After this, blood samples were taken and analyzed for serum testosterone and cortisol by ELISA and malondialdehyde levels colorimetrically. Data were analysed on SPSS version 13 and p<0.05 was considered significant. Results: There was no significant rise in testosterone cortisol ratio in rats supplemented with single antioxidant; however rats supplemented with combination of ascorbic acid and alpha tocopherol revealed significant rise in testosterone cortisol ratio with a fall in malondialdehyde levels. Conclusions: Synergistic effects of ascorbic acid and alpha tocopherol resulted in a decline in reactive oxygen species induced lipid peroxidation and rise of testosterone cortisol ratio. (author)

  3. A miniature glucose/O{sub 2} biofuel cell with a high tolerance against ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Zhang, L. [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing (China); Graduate School of CAS, Beijing (China); Su, L. [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing (China); Ohsaka, T. [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Midori-ku, Yokohama (Japan); Mao, L.

    2009-02-15

    This study demonstrates a miniature glucose/O{sub 2} biofuel cell (BFC) with a high tolerance against physiological level of ascorbic acid (AA) by immobilising ascorbate oxidase (AAox) on both the bioanode and the biocathode. Single-walled carbon nanotube (SWNT)-modified carbon fiber microelectrodes (CFMEs) are employed as the substrate electrode for the bioanode and biocathode. Glucose dehydrogenase (GDH) and bilirubin oxidase (BOD) are used as the biocatalysts for the electro-oxidation of glucose and for the electro-reduction of oxygen, respectively. SWNTs are used as the support for the both, stably confining the electrocatalyst (i.e. polymerised methylene blue, polyMB) for the oxidation of NADH co-factor for GDH and efficiently facilitating direct electrochemistry of the cathodic biocatalyst (i.e. BOD) for O{sub 2} reduction. The prepared micro-sized GDH-based bioanode and BOD-based biocathode employed for the bioelectrocatalytic oxidation of glucose and reduction of oxygen, respectively, are further over-coated with AAox to give a miniature glucose/O{sub 2} BFC with a high tolerance against AA. The maximum power density and the open circuit voltage (OCV) of the assembled glucose/O{sub 2} BFC are 52 {mu}W cm{sup -2} and 0.60 V, respectively. These values remain unchanged with the presence of AA in solution. In the human serum containing 10 mM NAD{sup +} and under ambient air, the maximum power density and the OCV of the assembled glucose/O{sub 2} BFC with AAox immobilisation on both the bioanode and the biocathode are 35 {mu}W cm{sup -2} and 0.39 V, respectively. These values are remarkably larger than those of the glucose/O{sub 2} BFC without AAox immobilisation on both the bioanode and the biocathode. This study could offer a new route to the development of enzymatic BFCs with promising application in real biological systems. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  4. Determination of uric acid in human urine by eliminating ascorbic acid interference on copper(II)-polydopamine immobilized electrode surface

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • A simple strategy for preparation of ploydopamine-Cu(II) coating on electrode. • The sensor shows the extraordinary selectivity for electrochemical determination of UA. • Modified electrode was characterized in detail. • Practical application was demonstrated in urine samples. - Abstract: The polydopamine (PD) coating was spontaneously formed through simple immersion of glassy carbon (GC) electrode in a dilute aqueous solution of dopamine (DA) at acidic solution (pH = 4.5) in the presence of Cu2+. Copper(II) ions were anchored on surface of GC electrode to prepare a PD-Cu(II) modified electrode. The morphology, composition and electrochemical properties of the PD-Cu(II) films were characterized by scanning electron microscopy, energy-dispersive spectrometry, X-ray photoelectron spectroscopy, powder X-ray diffraction, electrochemical impedance spectroscopy and cyclic voltammetry. This modified electrode shows the extraordinary selectivity for electrochemical determination of uric acid (UA) without interference of high concentration of ascorbic acid (AA). Under coexistence of 5 mM AA, the differential pulse voltammetry peak current of UA give linear response over the range of 0.06–1.68 mM (R2= 0.9934) with detection limit of 24.6 ?M (S/N = 3). Furthermore, the proposed sensor is ideal for the analysis of UA in human urine samples providing satisfactory results

  5. Effect of the Ascorbic Acid, Pyridoxine and Hydrogen Peroxide Treatments on Germination, Catalase Activity, Protein and Malondialdehyde Content of Three Oil Seeds

    Directory of Open Access Journals (Sweden)

    Seyed Ali Mohammad MODARRES SANAVY

    2008-08-01

    Full Text Available Oil seed production has an important role in human nutrition and industry. Success in oil plant cultivation is related to seed production with high viability and rapid germination, because these seeds rapidly loose their viability by fats oxidation. Thus, in this work we studied the effects of ascorbic acid, pyridoxine and hydrogen peroxide solutions on germination quantitative traits, catalase activity, protein and malondialdehyde content of three old oil seeds (sunflower, rape seed and safflower. The results showed that ascorbic acid and pyridoxine stimulated significantly the sunflower and rape seed germination. These vitamins, however, didn't have any effect on safflower germination. Hydrogen peroxide strongly increased safflower germination. Ascorbic acid and pyridoxine decreased catalase activity in sunflower and rape seed, whereas hydrogen peroxide increased it. Ascorbic acid and pyridoxine prevented protein degradation and lipid peroxidation in germinated seeds. Consequently, we understand that ascorbic acid and pyridoxine can increase sunflower and rape seed germination and stimulate rate of growth. Also safflower germination increased due to germination inhibitor oxidation by hydrogen peroxide. In conclusion, this report shows that oil seeds treated with ascorbic acid, pyridoxine and hydrogen peroxide remarkably increase the capacity of germination. We suggest that treatments with such substances can improve the old oil seed germination during storage.

  6. Addition of l-ascorbic acid to culture and vitrification media of IVF porcine blastocysts improves survival and reduces HSPA1A levels of vitrified embryos.

    Science.gov (United States)

    Castillo-Martín, Miriam; Yeste, Marc; Soler, Albert; Morató, Roser; Bonet, Sergi

    2014-04-17

    The aim of the present study was to determine the effect of l-ascorbic acid on embryo quality and gene expression of porcine blastocysts after supplementations of in vitro culture medium and/or vitrification-warming media. Embryo quality, in terms of total cell number (TCN), DNA fragmentation and peroxide levels, together with the relative transcript abundance of BCL-2 associated X protein (BAX), BCL2-like 1 (BCL2L1), POU class 5 homeobox 1 (POU5F1) and heat shock protein 70 (HSPA1A), was analysed. In Experiment 1, gene expression and embryo quality of fresh blastocysts were evaluated after culture with or without l-ascorbic acid; no significant differences were observed between the groups. In Experiment 2, blastocysts cultured with or without l-ascorbic acid were vitrified using two different vitrification solutions, supplemented or not with l-ascorbic acid. Supplementation of culture and vitrification media significantly enhanced survival rates and reduced peroxide levels. No significant differences in TCN, DNA fragmentation and BAX, BCL2L1 and POU5F1 expression were found in vitrified blastocysts among experimental groups. Vitrification procedures increase HSPA1A transcript abundance, but this increase was significantly lower in embryos cultured and/or vitrified with l-ascorbic acid. Thus, supplementing culture and/or vitrification media with l-ascorbic acid enhances survival rates of porcine blastocysts, suggesting a relationship with HSPA1A expression. PMID:25322209

  7. Scientific Opinion on the safety and efficacy of vitamin C (ascorbic acid, sodium ascorbate, calcium ascorbate, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate as a feed additive for all animal species based on a dossier submitted by DSM Nutritional Products Ltd

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-02-01

    Full Text Available Vitamin C is essential for primates, guinea pigs and fish. Vitamin C, in the form of ascorbic acid and its calcium and sodium salts, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate, is safe for all animal species. Setting a maximum content in feed and water for drinking is not considered necessary. Data on the vitamin C consumption of consumers are based on the levels of vitamin C in foodstuffs, including food of animal origin, produced in accordance with current EU legislation on the supplementation of feed with vitamin C. The exposure is far below the guidance level. Any potential contribution of the use of vitamin C in feed is therefore already considered in the above data. Consequently, the use of vitamin C in animal nutrition is not of concern for consumer safety. In the absence of inhalation toxicity studies it would be prudent to assume that inhalation of dust from the additives presents a health hazard to workers. Sodium calcium ascorbyl phosphate is not an irritant to skin and eyes and is unlikely to be a skin sensitiser. This conclusion is extrapolated to sodium ascorbyl phosphate. In the absence of data, ascorbic acid, sodium ascorbate, calcium ascorbate and ascorbyl palmitate should be considered as irritant to skin and eyes and as dermal sensitisers. The supplementation of feed with vitamin C does not pose a risk to the environment. Ascorbic acid, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate are regarded as effective sources of vitamin C when added to feed or water for drinking. Since ascorbic acid, sodium ascorbate, calcium ascorbate and ascorbyl palmitate are authorised for use as antioxidants in food and their function in feed is essentially the same as that in food, no further demonstration of efficacy is considered necessary.

  8. Ascorbic acid and citric flavonoids for broilers under heat stress: effects on performance and meat quality

    Directory of Open Access Journals (Sweden)

    JEM Peña

    2008-06-01

    Full Text Available The aim of this study was to evaluate the effects of increasing doses of ascorbic acid (AA and citric flavonoids (quercetin and rutin on the performance and meat quality characteristics of broilers submitted to cyclic heat stress. Four-hundred one-day-old female Ross 308 were housed in 40 battery cages a in temperature controlled room. Treatments consisted of 0, 250, 500, and 1000 g/ton on of AA + citric flavonoids. Birds were fed ad libitum until 32 day of age. Beginning on day 14 post-hatch until the end of the experiment, in order to simulate cyclic heat stress, the temperature inside the room was increased to 32°C for 5 hours, and decreased until reaching the comfort temperature corresponding to the age of the animals. Birds were slaughtered at 33 days of age, and carcass and commercial cuts yields were determined. Thighs and boneless breast samples were collected and frozen for subsequent analyses of pH, cooking loss, shear force, color, and Thiobarbituric Acid Reactive Substances (TBARS. Significant differences (p <0.05 were found for feed efficiency from 1 to 7 days of age, with the best values for the birds fed 0 and 250 g/ton on of AA + citric flavonoids. At the end of the experiment, there were no differences in other performance variables, carcass and parts yields, pH, shear force, color and TBARS. The meat of the birds supplemented with 250 g/ton on of product presented the lowest cooking loss.

  9. A novel amperometric sensor for ascorbic acid based on poly(Nile blue A) and functionalised multi-walled carbon nanotube modified electrodes.

    Science.gov (United States)

    Kul, Dilek; Ghica, M Emilia; Pauliukaite, Rasa; Brett, Christopher M A

    2013-07-15

    A new type of modified electrode sensor for ascorbic acid has been prepared by deposition of multi-walled carbon nanotubes (MWCNT) and poly(Nile blue A) on the surface of glassy carbon electrodes. Nile blue A was electropolymerised either beneath (directly on glassy carbon) or onto the MWCNT layer by potential cycling in phosphate buffer solution at pH 6.0. Characterisation of the modified electrodes was carried out by cyclic voltammetry and electrochemical impedance spectroscopy. Quantitative determination of ascorbate was achieved by cyclic voltammetry and fixed potential amperometry in phosphate buffer solution at pH 5.3. The modified electrodes exhibited good sensitivity, wide linear range, a detection limit of 1.6 ?M and good stability, showing that they can be used as sensors for ascorbic acid. There is no interference from compounds commonly found in clinical and pharmaceutical samples and the determination of ascorbic acid in commercial tablet samples was successfully performed. PMID:23622528

  10. Avaliação da interferência do ácido ascórbico na detecção da glicosúria / Evaluation of ascorbic acid interference in the detection of glycosuria

    Scientific Electronic Library Online (English)

    Jaime Murilo Fernandes, Costa; Maria Elizabete, Mendes; Nairo Massakazu, Sumita.

    2012-02-01

    Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese INTRODUÇÃO: O ácido ascórbico (vitamina C) é comumente ingerido como suplemento vitamínico. É uma vitamina hidrossolúvel, excretada pela urina e pode interferir nos ensaios laboratoriais, como nas reações de oxirredução para detecção da glicosúria. OBJETIVO: Este trabalho tem como objetivo avaliar a [...] interferência do ácido ascórbico na detecção de glicosúria pelo método de química seca por meio do uso de tiras reagentes. MATERIAIS E MÉTODOS: Amostras de urina foram avaliadas no analisador da marca Clinitek Atlas (Siemens Healthcare Diagnostics Inc., EUA). Foram selecionadas quatro amostras de urina com diferentes concentrações de glicose: 100 mg/dl, 250 mg/dl, 500 mg/dl e 1.000 mg/dl. Para cada concentração de glicose foram criadas cinco alíquotas, adicionando-se uma solução de ácido ascórbico 200 mg/dl, suficiente para obter uma concentração final de ácido ascórbico de 20 mg/dl no primeiro tubo, de 50 mg/dl no segundo tubo, de 270 mg/dl no terceiro tubo, de 1.000 mg/dl no quarto tubo e de 2.000 mg/dl no quinto tubo. Após essa adição, as amostras foram novamente avaliadas no analisador Clinitek Atlas. RESULTADOS: Nas amostras com concentração de 20 mg/dl de ácido, não se evidenciou interferência. Nas concentrações iguais e acima de 50 mg/dl, a interferência do ácido ascórbico se fez presente, sendo que o fato foi caracterizado pelos resultados falso negativos para detecção da glicose urinária. CONCLUSÃO: Os resultados demonstraram a interferência do ácido ascórbico no método da química seca (tiras reagentes), subestimando o nível de glicose urinária. Abstract in english INTRODUCTION: Ascorbic acid (vitamin C) is commonly used as a vitamin supplement. It is a water soluble vitamin, which is excreted through urine and may interfere in laboratory tests as well as redox reactions for urinary glucose detection. OBJECTIVE: This study aims to assess ascorbic acid interfer [...] ence in glycosuria detection by dry chemistry method (reagent strips). MATERIAL AND METHODS: Urine samples were evaluated by using Clinitek Atlas chemistry analyzer (Siemens Healthcare Diagnostics Inc., USA). Four urine samples with different glucose concentrations were selected: 100 mg/dl, 250 mg/dl, 500 mg/dl and > 1,000 mg/dl. 5 aliquots were created for each glucose concentration and a solution of ascorbic acid 200 mg/dl was added, sufficient to obtain a final ascorbic acid concentration of 20 mg/dl in the first tube, 50 mg/dl in the second tube, 270 mg/dl in the third tube, 1,000 mg/dl the fourth tube, and 2,000 mg/dl in the fifth tube. After the addition of ascorbic acid, the samples were reassessed by using Clinitek Atlas chemistry analyzer. RESULTS: There was no interference at concentrations of 20 mg/dl. However, there was ascorbic acid interference at concentrations higher than or equal to 50 mg/dl, which was characterized by false-negative results for urinary glucose detection. CONCLUSION: The results corroborated the interference of ascorbic acid in dry chemistry method (reagent strips) inasmuch as it underestimates urinary glucose levels.

  11. Avaliação da interferência do ácido ascórbico na detecção da glicosúria Evaluation of ascorbic acid interference in the detection of glycosuria

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    Jaime Murilo Fernandes Costa

    2012-02-01

    Full Text Available INTRODUÇÃO: O ácido ascórbico (vitamina C é comumente ingerido como suplemento vitamínico. É uma vitamina hidrossolúvel, excretada pela urina e pode interferir nos ensaios laboratoriais, como nas reações de oxirredução para detecção da glicosúria. OBJETIVO: Este trabalho tem como objetivo avaliar a interferência do ácido ascórbico na detecção de glicosúria pelo método de química seca por meio do uso de tiras reagentes. MATERIAIS E MÉTODOS: Amostras de urina foram avaliadas no analisador da marca Clinitek Atlas (Siemens Healthcare Diagnostics Inc., EUA. Foram selecionadas quatro amostras de urina com diferentes concentrações de glicose: 100 mg/dl, 250 mg/dl, 500 mg/dl e 1.000 mg/dl. Para cada concentração de glicose foram criadas cinco alíquotas, adicionando-se uma solução de ácido ascórbico 200 mg/dl, suficiente para obter uma concentração final de ácido ascórbico de 20 mg/dl no primeiro tubo, de 50 mg/dl no segundo tubo, de 270 mg/dl no terceiro tubo, de 1.000 mg/dl no quarto tubo e de 2.000 mg/dl no quinto tubo. Após essa adição, as amostras foram novamente avaliadas no analisador Clinitek Atlas. RESULTADOS: Nas amostras com concentração de 20 mg/dl de ácido, não se evidenciou interferência. Nas concentrações iguais e acima de 50 mg/dl, a interferência do ácido ascórbico se fez presente, sendo que o fato foi caracterizado pelos resultados falso negativos para detecção da glicose urinária. CONCLUSÃO: Os resultados demonstraram a interferência do ácido ascórbico no método da química seca (tiras reagentes, subestimando o nível de glicose urinária.INTRODUCTION: Ascorbic acid (vitamin C is commonly used as a vitamin supplement. It is a water soluble vitamin, which is excreted through urine and may interfere in laboratory tests as well as redox reactions for urinary glucose detection. OBJECTIVE: This study aims to assess ascorbic acid interference in glycosuria detection by dry chemistry method (reagent strips. MATERIAL AND METHODS: Urine samples were evaluated by using Clinitek Atlas chemistry analyzer (Siemens Healthcare Diagnostics Inc., USA. Four urine samples with different glucose concentrations were selected: 100 mg/dl, 250 mg/dl, 500 mg/dl and > 1,000 mg/dl. 5 aliquots were created for each glucose concentration and a solution of ascorbic acid 200 mg/dl was added, sufficient to obtain a final ascorbic acid concentration of 20 mg/dl in the first tube, 50 mg/dl in the second tube, 270 mg/dl in the third tube, 1,000 mg/dl the fourth tube, and 2,000 mg/dl in the fifth tube. After the addition of ascorbic acid, the samples were reassessed by using Clinitek Atlas chemistry analyzer. RESULTS: There was no interference at concentrations of 20 mg/dl. However, there was ascorbic acid interference at concentrations higher than or equal to 50 mg/dl, which was characterized by false-negative results for urinary glucose detection. CONCLUSION: The results corroborated the interference of ascorbic acid in dry chemistry method (reagent strips inasmuch as it underestimates urinary glucose levels.

  12. Chemometric-assisted kinetic-spectrophotometric method for simultaneous determination of ascorbic acid, uric acid, and dopamine.

    Science.gov (United States)

    Moghadam, Masoud Rohani; Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shahbazikhah, Parviz

    2011-03-15

    A chemometric-assisted kinetic spectrophotometric method has been developed for simultaneous determination of ascorbic acid (AA), uric acid (UA), and dopamine (DA). This method relies on the difference in the kinetic rates of the reactions of analytes with a common oxidizing agent, tris(1,10-phenanthroline) and iron(III) complex (ferritin, [Fe(phen)(3)](3+)) at pH 4.4. The changes in absorbance were monitored spectrophotometrically. The data obtained from the experiments were processed by chemometric methods of artificial neural network (ANN) and partial least squares (PLS). Acceptable techniques of prediction set, randomization t test, cross-validation, and Y randomization were applied for the selection of the best chemometric method. The results showed that feedforward artificial neural network (FFANN) is more efficient than the other chemometric methods. The parameters affecting the experimental conditions were optimized, and it was found that under optimal conditions Beer's law is followed in the concentration ranges of 4.3-74.1, 4.3-78.3, and 2.0-33.0 ?M for AA, UA, and DA, respectively. The proposed method was successfully applied to the determination of analytes in serum and urine samples. PMID:21078280

  13. Simultaneous Electrochemical Determination of Uric Acid and Ascorbic Acid Using L-Cysteine Self-Assembled Gold Electrode

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    Yuqing Zhao, Junyue Bai, Liang Wang, Xu Hong, Pengfei Huang, Hongjing Wang, Liying Zhang

    2006-11-01

    Full Text Available The electrochemical behaviors of uric acid (UA and ascorbic acid (AA at the L-cysteine (L-Cys self-assembled monolayers modified gold electrode (L-Cys/Au electrode have been studied. The modified electrode shows an excellent electrocatalytical effect on the oxidation of UA and AA by cyclic voltammetry (CV in 0.1 M phosphate buffer solution (pH 7.0. In differential pulse voltammetric (DPV measurements, the L-Cys/Au electrode can separate the oxidation peak potentials of UA and AA present in homogeneous solution by about 236 mV though the bare electrode give a single broad response. A successful elimination of the fouling effect by the oxidized product of AA on the response of UA has been achieved at the L-Cys/Au electrode. The detection limit of UA and AA is 2.0 × 10-6 M and 1.1 × 10-5 M, respectively. The proposed method can be used for the determination of UA in urine sample. The method is simple, quick, sensitive and accurate.

  14. Noncovalent nanohybrid of cobalt tetraphenylporphyrin with graphene for simultaneous detection of ascorbic acid, dopamine, and uric acid

    International Nuclear Information System (INIS)

    Highlights: •A noncovalent nanohybrid of cobalt tetraphenylporphyrin with chemically reduced graphene oxide was prepared. •The nanohybrid was characterized by UV–vis spectroscopy, Raman spectroscopy, and atomic force microscopy. •The nanohybrid can be applied to simultaneously detect AA, DA and UA with high sensitivity and low detection limit. -- Abstract: A noncovalent nanohybrid of cobalt tetraphenylporphyrin (CoTPP) with chemically reduced graphene oxide (CRGO) was prepared through ?–? stacking interaction between CRGO and CoTPP. The hybrid (CoTPP-CRGO) was characterized by UV–vis spectroscopy, Raman spectroscopy, and atomic force microscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) at CoTPP-CRGO modified glass carbon electrode (CoTPP-CRGO/GCE) were studied by cyclic voltammetry (CV). Three well-resolved oxidation peaks were obtained. The peak potential separations were 225 and 140 mV for AA and DA, DA and UA respectively. Owing to the synergistic effect of CoTPP and CRGO, CoTPP-CRGO showed faster electron transfer and stronger electrocatalysis than CoTPP, CRGO or their mixture. The proposed modified electrode exhibited linear responses to AA, DA and UA in the ranges of 5.0–200.0 ?M, 0.1–12.0 ?M, 0.5–40 ?M, respectively. The detection limits were 1.2, 0.03, and 0.15 ?M, respectively. It was also applied to detect real samples with a satisfactory result

  15. Long-distance transport of L-ascorbic acid in potato

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    Alberino Salvatore

    2004-09-01

    Full Text Available Abstract Background Following on from recent advances in plant AsA biosynthesis there is increasing interest in elucidating the factors contributing to the L-ascorbic acid (AsA content of edible crops. One main objective is to establish whether in sink organs such as fruits and tubers, AsA is synthesised in situ from imported photoassimilates or synthesised in source tissues and translocated via the phloem. In the current work we test the hypothesis that long-distance transport is involved in AsA accumulation within the potato tuber, the most significant source of AsA in the European diet. Results Using the EDTA exudation technique we confirm the presence of AsA in the phloem of potato plants and demonstrate a correlation between changes in the AsA content of source leaves and that of phloem exudates. Comparison of carboxyflourescein and AgNO3 staining is suggestive of symplastic unloading of AsA in developing tubers. This hypothesis was further supported by the changes in AsA distribution during tuber development which closely resembled those of imported photoassimilates. Manipulation of leaf AsA content by supply of precursors to source leaves resulted in increased AsA content of developing tubers. Conclusion Our data provide strong support to the hypothesis that long-distance transport of AsA occurs in potato. We also show that phloem AsA content and AsA accumulation in sink organs can be directly increased via manipulation of AsA content in the foliage. We are now attempting to establish the quantitative contribution of imported AsA to overall AsA accumulation in developing potato tubers via transgenic approaches.

  16. Combining reduced glutathione and ascorbic acid has supplementary beneficial effects on boar sperm cryotolerance.

    Science.gov (United States)

    Giaretta, Elisa; Estrada, Efrén; Bucci, Diego; Spinaci, Marcella; Rodríguez-Gil, Joan E; Yeste, Marc

    2015-02-01

    The main aim of this work was to evaluate how supplementing freezing and thawing media with reduced glutathione (GSH) and l-ascorbic acid (AA) affected the quality parameters of frozen-thawed boar spermatozoa. With this purpose, semen samples of 12 ejaculates coming from 12 boars were used. Each ejaculate was split into seven aliquots to which 5 mM of GSH and 100 ?M of AA were added separately or together at two different steps of freeze-thawing. Various sperm parameters (levels of free cysteine residues in sperm nucleoproteins, sperm viability, acrosome membrane integrity, intracellular peroxide and superoxide levels [ROS], and total and progressive motility) were evaluated before freezing and at 30 and 240 minutes after thawing. Both GSH and AA significantly improved boar sperm cryotolerance when they were separately added to freezing and thawing media. However, the highest improvement was recorded when both freezing and thawing media were supplemented with 5 mM of GSH plus 100 ?M of AA. This improvement was observed in sperm viability and acrosome integrity, sperm motility, and nucleoprotein structure. Although ROS levels were not much increased by freeze-thawing procedures, the addition of GSH and AA to both freezing and thawing extenders significantly decreased intracellular peroxide levels and had no impact on superoxide levels. According to our results, we can conclude that supplementation of freezing and thawing media with both GSH and AA has a combined, beneficial effect on frozen-thawed boar sperm, which is greater than that obtained with the separate addition of either GSH or AA. PMID:25459422

  17. Modulatory effect of ascorbic acid on physiological responses of transported ostrich chicks

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    Minka N. Salka

    2012-05-01

    Full Text Available The aims of this study were to determine the modulating role of ascorbic acid (AA on rectal temperature (RT, heterophil to lymphocyte (H to L ratio and aberrant behaviours of ostrich chicks transported by road for 4 h during hot-dry conditions. Twenty ostrich chicks aged 2.5 months, of both sexes and belonging to the Red Neck breed, served as subjects of the study. The chicks were assigned randomly to AA-treated and control groups, consisting of 10 chicks each. The AA-treated group was administered orally with 100 mg/kg body weight of AA dissolved in 5 mL of sterile water 30 min before transportation, whilst the control group was given the equivalent of sterile water only. The thermal load (TL experienced in the vehicle during transportation fluctuated between 31 °C and 89 °C, as calculated from the ambient temperature and relative humidity. Transportation induced hyperthermia, lymphopenia, heterophilia and aberrant behaviours of pecking, wing fluffing and panting, which were ameliorated by AA administration. The relationships between the TL, journey duration and physiological variables of RT, H to L ratio and aberrant behaviours recorded during transportation were significantly and positively correlated in the control group. In AA-treated group the relationships were not significantly correlated. In conclusion, the results showed for the first time that AA ameliorated the adverse effects of stress caused by road transportation on the aberrant behaviours, RT and H to L ratio of ostrich chicks during the hot-dry season.

  18. Ascorbate metabolism and the developmental demand for tartaric and oxalic acids in ripening grape berries

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    Soole Kathleen L

    2009-12-01

    Full Text Available Abstract Background Fresh fruits are well accepted as a good source of the dietary antioxidant ascorbic acid (Asc, Vitamin C. However, fruits such as grapes do not accumulate exceptionally high quantities of Asc. Grapes, unlike most other cultivated fruits do however use Asc as a precursor for the synthesis of both oxalic (OA and tartaric acids (TA. TA is a commercially important product in the wine industry and due to its acidifying effect on crushed juice it can influence the organoleptic properties of the wine. Despite the interest in Asc accumulation in fruits, little is known about the mechanisms whereby Asc concentration is regulated. The purpose of this study was to gain insights into Asc metabolism in wine grapes (Vitis vinifera c.v. Shiraz. and thus ascertain whether the developmental demand for TA and OA synthesis influences Asc accumulation in the berry. Results We provide evidence for developmentally differentiated up-regulation of Asc biosynthetic pathways and subsequent fluctuations in Asc, TA and OA accumulation. Rapid accumulation of Asc and a low Asc to dehydroascorbate (DHA ratio in young berries was co-ordinated with up-regulation of three of the primary Asc biosynthetic (Smirnoff-Wheeler pathway genes. Immature berries synthesised Asc in-situ from the primary pathway precursors D-mannose and L-galactose. Immature berries also accumulated TA in early berry development in co-ordination with up-regulation of a TA biosynthetic gene. In contrast, ripe berries have up-regulated expression of the alternative Asc biosynthetic pathway gene D-galacturonic acid reductase with only residual expression of Smirnoff-Wheeler Asc biosynthetic pathway genes and of the TA biosynthetic gene. The ripening phase was further associated with up-regulation of Asc recycling genes, a secondary phase of increased accumulation of Asc and an increase in the Asc to DHA ratio. Conclusion We demonstrate strong developmental regulation of Asc biosynthetic, recycling and catabolic genes in grape berries. Integration of the transcript, radiotracer and metabolite data demonstrates that Asc and TA metabolism are developmentally regulated in grapevines; resulting in low accumulated levels of the biosynthetic intermediate Asc, and high accumulated levels of the metabolic end-product TA.

  19. Oral high dose ascorbic acid treatment for one year in young CMT1A patients: a randomised, double-blind, placebo-controlled phase II trial

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    de Visser Marianne

    2009-11-01

    Full Text Available Abstract Background High dose oral ascorbic acid substantially improved myelination and locomotor function in a Charcot-Marie-Tooth type 1A mouse model. A phase II study was warranted to investigate whether high dose ascorbic acid also has such a substantial effect on myelination in Charcot-Marie-Tooth type 1A patients and whether this treatment is safe. Methods Patients below age 25 years were randomly assigned to receive placebo or ascorbic acid (one gram twice daily in a double-blind fashion during one year. The primary outcome measure was the change over time in motor nerve conduction velocity of the median nerve. Secondary outcome measures included changes in minimal F response latencies, compound muscle action potential amplitude, muscle strength, sensory function, Charcot-Marie-Tooth neuropathy score, and disability. Results There were no significant differences between the six placebo-treated (median age 16 years, range 13 to 24 and the five ascorbic acid-treated (19, 14 to 24 patients in change in motor nerve conduction velocity of the median nerve (mean difference ascorbic acid as opposed to placebo treatment of 1.3 m/s, confidence interval -0.3 to 3.0 m/s, P = 0.11 or in change of any of the secondary outcome measures over time. One patient in the ascorbic acid group developed a skin rash, which led to discontinuation of the study medication. Conclusion Oral high dose ascorbic acid for one year did not improve myelination of the median nerve in young Charcot-Marie-Tooth type 1A patients. Treatment was relatively safe. Trial registration Current Controlled Trials ISRCTN56968278, ClinicalTrials.gov NCT00271635.

  20. Chemical repair of base lesions, AP-sites, and strand breaks on plasmid DNA in dilute aqueous solution by ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Hata, Kuniki [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakatashirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Urushibara, Ayumi; Yamashita, Shinichi; Shikazono, Naoya; Yokoya, Akinari [Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakatashirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Katsumura, Yosuke, E-mail: katsu@n.t.u-tokyo.ac.jp [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakatashirane, Tokai-mura, Naka-gun, Ibaraki 319-1188 (Japan)

    2013-05-03

    Highlights: •We report a novel mechanism of radiation protection of DNA by chemical activity of ascorbic acid. •The “chemical repair” of DNA damage was revealed using biochemical assay and chemical kinetics analysis. •We found that ascorbic acid significantly repairs precursors of nucleobase lesions and abasic sites. •However, ascorbic acid seldom repairs precursors of DNA-strand breaks. -- Abstract: We quantified the damage yields produced in plasmid DNA by ?-irradiation in the presence of low concentrations (10–100 ?M) of ascorbic acid, which is a major antioxidant in living systems, to clarify whether it chemically repairs radiation damage in DNA. The yield of DNA single strand breaks induced by irradiation was analyzed with agarose gel electrophoresis as conformational changes in closed circular plasmids. Base lesions and abasic sites were also observed as additional conformational changes by treating irradiated samples with glycosylase proteins. By comparing the suppression efficiencies to the induction of each DNA lesion, in addition to scavenging of the OH radicals derived from water radiolysis, it was found that ascorbic acid promotes the chemical repair of precursors of AP-sites and base lesions more effectively than those of single strand breaks. We estimated the efficiency of the chemical repair of each lesion using a kinetic model. Approximately 50–60% of base lesions and AP-sites were repaired by 10 ?M ascorbic acid, although strand breaks were largely unrepaired by ascorbic acid at low concentrations. The methods in this study will provide a route to understanding the mechanistic aspects of antioxidant activity in living systems.

  1. Interactions of peroxynitrite, tetrahydrobiopterin, ascorbic acid, and thiols: implications for uncoupling endothelial nitric-oxide synthase.

    Science.gov (United States)

    Kuzkaya, Nermin; Weissmann, Norbert; Harrison, David G; Dikalov, Sergey

    2003-06-20

    Tetrahydrobiopterin (BH4) serves as a critical co-factor for the endothelial nitric-oxide synthase (eNOS). A deficiency of BH4 results in eNOS uncoupling, which is associated with increased superoxide and decreased NO* production. BH4 has been suggested to be a target for oxidation by peroxynitrite (ONOO-), and ascorbate has been shown to preserve BH4 levels and enhance endothelial NO* production; however, the mechanisms underlying these processes remain poorly defined. To gain further insight into these interactions, the reaction of ONOO- with BH4 was studied using electron spin resonance and the spin probe 1-hydroxy-3-carboxy-2,2,5-tetramethyl-pyrrolidine. ONOO- reacted with BH4 6-10 times faster than with ascorbate or thiols. The immediate product of the reaction between ONOO- and BH4 was the trihydrobiopterin radical (BH3.), which was reduced back to BH4 by ascorbate, whereas thiols were not efficient in recycling of BH4. Uncoupling of eNOS caused by peroxynitrite was investigated in cultured bovine aortic endothelial cells (BAECs) by measuring superoxide and NO* using spin probe 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine and the NO*-spin trap iron-diethyldithiocarbamate. Bolus ONOO-, the ONOO- donor 3-morpholinosydnonimine, and an inhibitor of BH4 synthesis (2,4-diamino-6-hydroxypyrimidine) uncoupled eNOS, increasing superoxide and decreasing NO* production. Exogenous BH4 supplementation restored endothelial NO* production. Treatment of BAECs with both BH4 and ascorbate prior to ONOO- prevented uncoupling of eNOS by ONOO-. This study demonstrates that endothelial BH4 is a crucial target for oxidation by ONOO- and that the BH4 reaction rate constant exceeds those of thiols or ascorbate. We confirmed that ONOO- uncouples eNOS by oxidation of tetrahydrobiopterin and that ascorbate does not fully protect BH4 from oxidation but recycles BH3. radical back to BH4. PMID:12692136

  2. The novel Arabidopsis thaliana svt2 suppressor of the ascorbic acid-deficient mutant vtc1-1 exhibits phenotypic and genotypic instability [v1; ref status: indexed, http://f1000r.es/o2

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    Chase F Kempinski

    2013-01-01

    Full Text Available Ascorbic acid is a potent antioxidant that detoxifies reactive oxygen species when plants are exposed to unfavorable environmental conditions. In addition to its antioxidant properties, ascorbic acid and its biosynthetic precursors fulfill a variety of other physiological and molecular functions. A mutation in the ascorbic acid biosynthesis gene VTC1, which encodes GDP-mannose pyrophosphorylase, results in conditional root growth inhibition in the presence of ammonium. To isolate suppressors of vtc1-1, which is in the Arabidopsis Columbia-0 background, seeds of the mutant were subjected to ethyl methanesulfonate mutagenesis. A suppressor mutant of vtc1-1 2, svt2, with wild-type levels of ascorbic acid and root growth similar to the wild type in the presence of ammonium was isolated. Interestingly, svt2 has Arabidopsis Landsberg erecta features, although svt2 is delayed in flowering and has an enlarged morphology. Moreover, the svt2 genotype shares similarities with Ler polymorphism markers and sequences, despite the fact that the mutant derived from mutagenesis of Col-0 vtc1-1 seed. We provide evidence that svt2 is not an artifact of the experiment, a contamination of Ler seed, or a result of outcrossing of the svt2 mutant with Ler pollen. Instead, our results show that svt2 exhibits transgenerational genotypic and phenotypic instability, which is manifested in a fraction of svt2 progeny, producing revertants that have Col-like phenotypic and genotypic characteristics. Some of those Col-like revertants then revert back to svt2-like plants in the subsequent generation. Our findings have important implications for undiscovered phenomena in transmitting genetic information in addition to the Mendelian laws of inheritance. Our results suggest that stress can trigger a genome restoration mechanism that could be advantageous for plants to survive environmental changes for which the ancestral genes were better adapted.

  3. Electrochemical determination of dopamine in the presence of ascorbic acid based on the gold nanorods/carbon nanotubes composite film

    International Nuclear Information System (INIS)

    Highlights: ? The GNR/CNT/GC electrode was fabricated simply. It has higher catalytic activity towards the oxidation of DA and ascorbic acid (AA). The selective determination of DA was carried out with low detection limit (0.8 nM, S/N = 3). The proposed method was feasible to detect the concentration of DA in human blood serum. - Abstract: In this paper, the gold nanorods (GNRs)/multiwalled carbon nanotubes (CNT) composite film-modified glassy carbon (GC) electrode was fabricated simply by the electrostatic interaction between the positively charged GNRs and the negatively charged CNT. And the GNRs/CNT/GC electrode was used for the selective and sensitive determination of dopamine (DA) in the presence of ascorbic acid (AA). It was found that the GNRs/CNT/GC electrode had higher catalytic activity towards the oxidation of DA and ascorbic acid (AA) comparing with the bare GC and CNT/GC electrodes. It may be due to the synergic effect of GNRs and CNT, because the surface area of the GNRs/CNT/GC electrode increased, the edge plan sites presented on the CNT surface can improve the electron transfer between the modified electrode and DA, and the rod-shaped gold may be served as the mediator for the oxidation of dopamine and provided the electrocatalytic ability. Moreover, the voltammetric peaks of AA and DA were separated enough at the GNRs/CNT/GC electrode, which was sufficiently enough for the selective determination of DA. Thus, the selective determination of DA was cathe selective determination of DA was carried out with low detection limit (0.8 nM, S/N = 3). Also it was obtained that the proposed method was feasible to detect the concentration of DA in human blood serum. Therefore, it can be concluded that the GNRs/CNT modified electrode may be advantageous for the DA determination.

  4. Electrochemical determination of dopamine in the presence of ascorbic acid based on the gold nanorods/carbon nanotubes composite film

    Energy Technology Data Exchange (ETDEWEB)

    Deng Chunyan, E-mail: dengchunyan81@126.com [Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha, 410083 (China); Chen Jinzhuo; Yang Minghui [Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha, 410083 (China); Nie Zhou [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Si Shihui [Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha, 410083 (China)

    2011-10-01

    Highlights: > The GNR/CNT/GC electrode was fabricated simply. It has higher catalytic activity towards the oxidation of DA and ascorbic acid (AA). The selective determination of DA was carried out with low detection limit (0.8 nM, S/N = 3). The proposed method was feasible to detect the concentration of DA in human blood serum. - Abstract: In this paper, the gold nanorods (GNRs)/multiwalled carbon nanotubes (CNT) composite film-modified glassy carbon (GC) electrode was fabricated simply by the electrostatic interaction between the positively charged GNRs and the negatively charged CNT. And the GNRs/CNT/GC electrode was used for the selective and sensitive determination of dopamine (DA) in the presence of ascorbic acid (AA). It was found that the GNRs/CNT/GC electrode had higher catalytic activity towards the oxidation of DA and ascorbic acid (AA) comparing with the bare GC and CNT/GC electrodes. It may be due to the synergic effect of GNRs and CNT, because the surface area of the GNRs/CNT/GC electrode increased, the edge plan sites presented on the CNT surface can improve the electron transfer between the modified electrode and DA, and the rod-shaped gold may be served as the mediator for the oxidation of dopamine and provided the electrocatalytic ability. Moreover, the voltammetric peaks of AA and DA were separated enough at the GNRs/CNT/GC electrode, which was sufficiently enough for the selective determination of DA. Thus, the selective determination of DA was carried out with low detection limit (0.8 nM, S/N = 3). Also it was obtained that the proposed method was feasible to detect the concentration of DA in human blood serum. Therefore, it can be concluded that the GNRs/CNT modified electrode may be advantageous for the DA determination.

  5. Inhibitory action of antioxidants (ascorbic acid or ?-tocopherol on seizures and brain damage induced by pilocarpine in rats Ação inibitória de antioxidantes (ácido ascórbico e ?-tocoferol nas convulsões e dano cerebral em ratos induzidos pela pilocarpina

    Directory of Open Access Journals (Sweden)

    Adriana da Rocha Tomé

    2010-06-01

    Full Text Available Temporal lobe epilepsy is the most common form of epilepsy in humans. Oxidative stress is a mechanism of cell death induced by seizures. Antioxidant compounds have neuroprotective effects due to their ability to inhibit free radical production. The objectives of this work were to comparatively study the inhibitory action of antioxidants (ascorbic acid or ?-tocopherol on behavioral changes and brain damage induced by high doses of pilocarpine, aiming to further clarify the mechanism of action of these antioxidant compounds. In order to determinate neuroprotective effects, we studied the effects of ascorbic acid (250 or 500 mg/kg, i.p. and ?-tocopherol (200 or 400 mg/kg, i.p. on the behavior and brain lesions observed after seizures induced by pilocarpine (400 mg/kg, i.p., P400 model in rats. Ascorbic acid or ?-tocopherol injections prior to pilocarpine suppressed behavioral seizure episodes. These findings suggested that free radicals can be produced during brain damage induced by seizures. In the P400 model, ascorbic acid and ?-tocopherol significantly decreased cerebral damage percentage. Antioxidant compounds can exert neuroprotective effects associated with inhibition of free radical production. These results highlighted the promising therapeutic potential of ascorbic acid and ?-tocopherol in treatments for neurodegenerative diseases.A epilepsia de lobo temporal é a mais comum forma de epilepsia em humanos. O estresse oxidativo é um dos mecanismos de morte celular induzida pelas crises convulsivas. Os compostos antioxidantes apresentam efeitos neuroprotetores devido à sua capacidade de inibir a produção de radicais livres. Os objetivos do presente trabalho foram estudar de forma comparativa a ação inibitória de antioxidantes (ácido ascórbico e ?-tocoferol sobre as alterações comportamentais e histopatológicas no hipocampo de ratos após convulsões induzidas pela pilocarpina. A fim de determinar os efeitos neuroprotetores destas drogas, o presente trabalho estudou os efeitos do ácido ascórbico (250 ou 500 mg/kg, i.p. e do ?-tocoferol (200 ou 400 mg/kg, i.p. sobre o comportamento e as lesões cerebrais observados após convulsões induzidas pela pilocarpina (400 mg/kg, i.p., P400, em ratos. As injeções de ácido ascórbico ou ?-tocoferol antes da administração de pilocarpina reduzem o número de animais que convulsionam. Estes achados sugerem que os radicais livres podem induzir o desenvolvimento de lesão cerebral durante as crises epilépticas. No modelo P400, o ácido ascórbico e o ?-tocoferol, diminuem significativamente os danos cerebrais. Os compostos antioxidantes podem exercer efeitos neuroprotetores, e esses resultados podem estar associados à inibição da produção de radicais livres. Estes resultados sugerem um promissor potencial terapêutico tanto para o ácido ascórbico quanto para o ?-tocoferol no tratamento de doenças neurodegenerativas.

  6. Inhibitory action of antioxidants (ascorbic acid or ?-tocopherol) on seizures and brain damage induced by pilocarpine in rats / Ação inibitória de antioxidantes (ácido ascórbico e ?-tocoferol) nas convulsões e dano cerebral em ratos induzidos pela pilocarpina

    Scientific Electronic Library Online (English)

    Adriana da Rocha, Tomé; Paulo Michel Pinheiro, Ferreira; Rivelilson Mendes de, Freitas.

    2010-06-01

    Full Text Available A epilepsia de lobo temporal é a mais comum forma de epilepsia em humanos. O estresse oxidativo é um dos mecanismos de morte celular induzida pelas crises convulsivas. Os compostos antioxidantes apresentam efeitos neuroprotetores devido à sua capacidade de inibir a produção de radicais livres. Os ob [...] jetivos do presente trabalho foram estudar de forma comparativa a ação inibitória de antioxidantes (ácido ascórbico e ?-tocoferol) sobre as alterações comportamentais e histopatológicas no hipocampo de ratos após convulsões induzidas pela pilocarpina. A fim de determinar os efeitos neuroprotetores destas drogas, o presente trabalho estudou os efeitos do ácido ascórbico (250 ou 500 mg/kg, i.p.) e do ?-tocoferol (200 ou 400 mg/kg, i.p.) sobre o comportamento e as lesões cerebrais observados após convulsões induzidas pela pilocarpina (400 mg/kg, i.p., P400), em ratos. As injeções de ácido ascórbico ou ?-tocoferol antes da administração de pilocarpina reduzem o número de animais que convulsionam. Estes achados sugerem que os radicais livres podem induzir o desenvolvimento de lesão cerebral durante as crises epilépticas. No modelo P400, o ácido ascórbico e o ?-tocoferol, diminuem significativamente os danos cerebrais. Os compostos antioxidantes podem exercer efeitos neuroprotetores, e esses resultados podem estar associados à inibição da produção de radicais livres. Estes resultados sugerem um promissor potencial terapêutico tanto para o ácido ascórbico quanto para o ?-tocoferol no tratamento de doenças neurodegenerativas. Abstract in english Temporal lobe epilepsy is the most common form of epilepsy in humans. Oxidative stress is a mechanism of cell death induced by seizures. Antioxidant compounds have neuroprotective effects due to their ability to inhibit free radical production. The objectives of this work were to comparatively study [...] the inhibitory action of antioxidants (ascorbic acid or ?-tocopherol) on behavioral changes and brain damage induced by high doses of pilocarpine, aiming to further clarify the mechanism of action of these antioxidant compounds. In order to determinate neuroprotective effects, we studied the effects of ascorbic acid (250 or 500 mg/kg, i.p.) and ?-tocopherol (200 or 400 mg/kg, i.p.) on the behavior and brain lesions observed after seizures induced by pilocarpine (400 mg/kg, i.p., P400 model) in rats. Ascorbic acid or ?-tocopherol injections prior to pilocarpine suppressed behavioral seizure episodes. These findings suggested that free radicals can be produced during brain damage induced by seizures. In the P400 model, ascorbic acid and ?-tocopherol significantly decreased cerebral damage percentage. Antioxidant compounds can exert neuroprotective effects associated with inhibition of free radical production. These results highlighted the promising therapeutic potential of ascorbic acid and ?-tocopherol in treatments for neurodegenerative diseases.

  7. Monolayer covalent modification of 5-hydroxytryptophan on glassy carbon electrodes for simultaneous determination of uric acid and ascorbic acid

    International Nuclear Information System (INIS)

    5-Hydroxytryptophan (5-HTP) was covalently grafted on the surface of glassy carbon electrodes (GCEs) using cyclic voltammetric method in a phosphate buffer solution. The prepared electrode, denoded as 5-HTP/GCE, was characterized by X-ray photoelectron spectroscopy, cyclic voltammetry and differential pulse voltammetry (DPV). Tryptophan grafted GCE (TRP/GCE) and 5-hydroxytryptamine grafted GCE (5-HTP/GCE) were also prepared by the same method for comparison. It was found that the electrocatalytic activities toward the oxidation of uric acid (UA) and ascorbic acid (AA) was in the order of 5-HT/GCE > 5-HTP/GCE > TRP/GCE for UA oxidation and 5-HT/GCE 5-HTP/GCE > TRP/GCE for AA oxidation. However, the CV current sensitivity was estimated as 4:2:1 for 5-HTP/GCE:5-HT/GCE:TRP/GCE. The DPV peaks for UA and AA oxidation appeared at 0.07 V and 0.34 V versus SCE, respectively, allowing simultaneous determination in mixtures. A linearly response in the range of: 5.0 x 10-7 to 1.1 x 10-5 M with the detection limit (s/n = 3) of 2.8 x 10-7 M for UA determination, and a linear response in the range of: 5.0 x 10-6 to 1.0 x 10-4 M with the detection limit of 4.2 x 10-6 M for AA determination were obtained. This electrode was used for UA and AA determinations in human urine samples satisfactorily

  8. ZnO-CuxO/polypyrrole nanocomposite modified electrode for simultaneous determination of ascorbic acid, dopamine, and uric acid.

    Science.gov (United States)

    Ghanbari, Kh; Hajheidari, N

    2015-03-15

    Novel zinc oxide (ZnO) nanosheets and copper oxide (CuxO, CuO, and Cu2O) decorated polypyrrole (PPy) nanofibers (ZnO-CuxO-PPy) have been successfully fabricated for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The morphology and structure of ZnO-CuxO-PPy nanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. Compared with the bare glassy carbon electrode (GCE), PPy/GCE, CuxO-PPy/GCE, and ZnO-PPy/GCE, ZnO-CuxO-PPy/GCE exhibits much higher electrocatalytic activities toward the oxidation of AA, DA, and UA with increasing peak currents and decreasing oxidation overpotentials. Cyclic voltammetry (CV) results show that AA, DA, and UA could be detected selectively and sensitively at ZnO-CuxO-PPy/GCE with peak-to-peak separation of 150 and 154mV for AA-DA and DA-UA, respectively. The calibration curves for AA, DA, and UA were obtained in the ranges of 0.2 to 1.0mM, 0.1 to 130.0?M, and 0.5 to 70.0?M, respectively. The lowest detection limits (signal/noise=3) were 25.0, 0.04, and 0.2?M for AA, DA, and UA, respectively. With good selectivity and sensitivity, the current method was applied to the determination of DA in injectable medicine and UA in urine samples. PMID:25576954

  9. Preparation and dissolution of lanthanum-, cerium- and zirconium-containing magnetites in citric acid-EDTA-ascorbic acid mixtures

    International Nuclear Information System (INIS)

    If fission products such as lanthanum, cerium, and zirconium are present in corrosion product deposits of primary systems of nuclear reactors, then this can lead to an increased radiation field buildup. The minimization of such an activity buildup is normally done by a chemical decontamination process involving the dissolution of this oxide deposit (corrosion product, Fe3O4). Thus, the dissolution behavior of oxides of lanthanum, cerium, and zirconium in magnetite (equivalent to 1 metal at.% in magnetite) in citric acid-EDTA-ascorbic acid mixture is reported in this study. The oxides employed are prepared synthetically by a co-precipitation method and characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electronic microscopy, atomic absorption spectroscopy, energy dispersive X-ray analysis, and Branauer-Emmett-Teller surface area measurements. The addition of cerium during the preparation of magnetite resulted in a decreased particle size and hence in an increased surface of the oxide irrespective of the presence of lanthanum and zirconium. The dissolution behavior of magnetite was not affected by the presence of the fission products lanthanum, cerium, and zirconium at 1 at.% each, either individually or in combination. A dissolution rate coefficient of 3 x 10-3 s-1 (k1) and a y value of 1.3 was obtained by applying general kinetic equation, while using inverse cubic ratec equation, while using inverse cubic rate law, kobs was found to be 5.16 x 10-4 s-1. When the amount of the metals was ? 3 at.%, a turbidity was observed during the dissolution, which could be removed by filtration. (orig.)

  10. Radiation protection by 6-palmitoyl ascorbic acid-2-glucoside. Studies on DNA damage in vitro, ex vivo, in vivo and oxidative stress in vivo

    International Nuclear Information System (INIS)

    A palmitoyl derivative of ascorbic acid 2-glucoside, 6-palmitoyl ascorbic acid-2-glucoside (PAsAG), which possess good antioxidant properties, is examined for radioprotection in vitro, ex vivo and in vivo models. PAsAG protected plasmid DNA from gamma-radiation induced damages under in vitro conditions. Presence of 1.6 mM PAsAG inhibited the disappearance of ccc (covalently closed circular) form of plasmid pBR322 with a dose modifying factor of 1.5. Comet assay studies on mouse spleen cells exposed to 6 Gy gamma-radiation (ex vivo) in presence and absence of PAsAG revealed that cellular DNA was effectively protected by this compound from radiation induced damages. Oral administration of 80 mg/kg body weight of PAsAG to mice 1 hour prior to 6 Gy whole body gamma-radiation exposure, efficiently protected cellular DNA in tissues such as spleen, bone marrow and blood, from radiation induced damages as indicated by alkaline comet assay. Oxidative stress in tissues such as liver and brain of mice, following whole body exposure to various doses of gamma-radiation (2-8 Gy), monitored as levels of glutathione (GSH) and peroxidation of lipids, were found considerably reduced when PAsAG was orally administered (80 mg/kg body weight) to the mice one hour prior to the radiation exposure. PAsAG administration improved the per cent survival of mice following exposure to 10 Gy whole body gamma-radiation. Thus PAsAG could act as a radioprotector under in vitro, ex vivo and in vivo conor under in vitro, ex vivo and in vivo conditions of ionizing-radiation exposure. (author)

  11. Synergistic effects of tea polyphenols and ascorbic acid on human lung adenocarcinoma SPC-A-1 cells*

    OpenAIRE

    Li, Wei; Wu, Jian-xiang; Tu, You-ying

    2010-01-01

    Tea polyphenols have been shown to have ansticancer activity in many studies. In the present study, we investigated effects of theaflavin-3-3?-digallate (TF3), one of the major theaflavin monomers in black tea, in combination with ascorbic acid (AA), a reducing agent, and (?)-epigallocatechin-3-gallate (EGCG), the main polyphenol presented in green tea, in combination with AA on cellular viability and cell cycles of the human lung adenocarcinoma SPC-A-1 cells. The 3-(4,5-dimethylthiazol-2...

  12. Simultaneous Electrochemical Detection of Dopamine and Ascorbic Acid Using an Iron Oxide/Reduced Graphene Oxide Modified Glassy Carbon Electrode

    OpenAIRE

    Teo Peik-See; Alagarsamy Pandikumar; Huang Nay-Ming; Lim Hong-Ngee; Yusran Sulaiman

    2014-01-01

    The fabrication of an electrochemical sensor based on an iron oxide/graphene modified glassy carbon electrode (Fe3O4/rGO/GCE) and its simultaneous detection of dopamine (DA) and ascorbic acid (AA) is described here. The Fe3O4/rGO nanocomposite was synthesized via a simple, one step in-situ wet chemical method and characterized by different techniques. The presence of Fe3O4 nanoparticles on the surface of rGO sheets was confirmed by FESEM and TEM images. The electrochemical behavior of Fe3O4/r...

  13. Simultaneous Determination of Dopamine, Sertonin and Ascorbic Acid at a Glassy Carbon Electrode Modified with Carbon-Spheres

    OpenAIRE

    Feng Gao; Guozhi Wu; Xueyue Jiang; Meili Sheng; Jianqing Zhou

    2013-01-01

    A novel glassy carbon electrode (GCE) modi?ed with carbon-spheres has been fabricated through a simple casting procedure. The modified GCE displays high selectivity and excellent electrochemical catalytic activities towards dopamine (DA), serotonin (5-HT), and ascorbic acid (AA). In the co-existence system, the peak separations between AA and DA, DA and 5-HT, and AA and 5-HT are large up to 230, 180, and 410 mV, respectively. Differential pulse voltammetry (DPV) has been employed to simulta...

  14. Simultaneous Detection of Homocysteine and Cysteine in the Presence of Ascorbic Acid and Glutathione Using a Nanocarbon Modified Electrode

    OpenAIRE

    Lee, Pt; Lowinsohn, D.; Compton, Rg

    2014-01-01

    The simultaneous electrochemical detection of homocysteine and cysteine using an absorbed ortho-quinone species, catechol, at the nanocarbon modified glassy carbon electrode was achieved via 1,4-Michael addition reaction. The detection was done in the presence and the absence of each other as well as with both glutathione and ascorbic acid present in order to investigate the selectivity of homocysteine and cysteine. A determination of homocysteine sensitivity is (0.882±0.296)nAnM-1 with a LO...

  15. Ascorbic acid biosynthesis: a precursor study on plants Biossíntese de ácido ascórbico: um estudo com precursores em plantas

    OpenAIRE

    Barata-soares, Anderson D.; Gomez, Maria Luiza P. A.; Carlos Henrique de Mesquita; Lajolo, Franco M.

    2004-01-01

    Since the first isolation of ascorbic acid (AsA) in 1928, few papers have been published regarding the biosynthesis of AsA in plants, especially in fruits. It took as long as 1998, before Wheeler, Jones and Smirnoff, based on a study with Arabidopsis leaves, proposed what can be considered the main pathway of biosynthesis of AsA, in which L-galactose (L-GAL) is a key precursor. This paper reports the effectiveness of some precursors (cold or radiolabeled) in the biosynthesis of AsA in differe...

  16. The Influence of Two Lithium Forms on the Growth, l-Ascorbic Acid Content and Lithium Accumulation in Lettuce Plants

    OpenAIRE

    Kalinowska, Monika; Hawrylak-nowak, Barbara; Szyman?ska, Maria

    2013-01-01

    Lithium (Li) is a trace element that is essential in the human diet due to its importance for health and proper functioning of an organism. However, the biological activity of this metal in crop plants, which are the primary dietary sources of Li, is still poorly understood. The aim of the presented study was to comparatively analyse two Li chemical forms on the growth, as well as the l-ascorbic acid content, the Li accumulation and translocation in butterhead lettuce (Lactuca sativa L. var. ...

  17. REDUCTION OF L-METHIONINE SELENOXIDE TO SELENO-L-METHIONINE BY ENDOGENOUS THIOLS, ASCORBIC ACID, OR METHIMAZOLE

    OpenAIRE

    Krause, Renee J.; Elfarra, Adnan A.

    2008-01-01

    Seleno-L-methionine (SeMet) can be oxidized to L-methionine selenoxide (MetSeO) by flavin-containing monooxygenase 3 (FMO3) and rat liver microsomes in the presence of NADPH. MetSeO can be reduced by GSH to yield SeMet and GSSG. In the present study, the potential reduction of MetSeO to SeMet by other cellular components and antioxidants was investigated. Besides GSH, other thiols (L-cysteine, or N-acetyl-L-cysteine) and antioxidants (ascorbic acid and methimazole) also reduced MetSeO to SeMe...

  18. Simultaneous voltammetric determination of paracetamol and ascorbic acid using a boron-doped diamond electrode modified with Nafion and lead films.

    Science.gov (United States)

    Tyszczuk-Rotko, Katarzyna; B?czkowska, Ilona; Wójciak-Kosior, Magdalena; Sowa, Ireneusz

    2014-11-01

    The paper describes the fabrication and application of a novel sensor (a boron-doped diamond electrode modified with Nafion and lead films) for the simultaneous determination of paracetamol and ascorbic acid by differential pulse voltammetry. The main advantage of the lead film and polymer covered boron-doped diamond electrode is that the sensitivity of the stripping responses is increased and the separation of paracetamol and ascorbic acid signals is improved due to the modification of the boron-doped diamond surface by the lead layer. Additionally, the repeatability of paracetamol and ascorbic acid signals is improved by the application of the Nafion film coating. In the presence of oxygen, linear calibration curves were obtained in a wide concentration range from 5×10(-7) to 2×10(-4) mol L(-1) for paracetamol and from 1×10(-6) to 5×10(-4) mol L(-1) for ascorbic acid. The analytical utility of the differential pulse voltammetric method elaborated was tested in the assay of paracetamol and ascorbic acid in commercially available pharmaceutical formulations and the method was validated by high performance liquid chromatography coupled with diode array detector. PMID:25127609

  19. PENGARUH ASAM AKROBAT TERHADAP PEMBENTUKAN GEL MIOFIBRIL IKAN MATA BESAR (Selar crumenophthalnus [effect of ascorbic acid on gel formation of myofibril from big eye scad fish (Selar crumenophthalnus

    Directory of Open Access Journals (Sweden)

    Yuli Witono

    2005-08-01

    Full Text Available Effect of ascorbic acid on gel formation of myofibril from big eye scad fish (Selar crumenophthalnuswere studied for its development as food ingredient. Myofibril was galled by the addition of various concentrations of ascorbic acid (0, 0.1, 0.2, 0.3 and 0.4% and the gels were then characterized for its cooking loss, of the gel, but at 0.4% the cooking loss of gel increased significantly. Accordingly, the WHC of the gel changed insignificantly with the ascorbic acid addition below 0.3%, and decrease sharply in the addition of 0.4%. Gel textures were affected by the addition of ascorbic acid at all levels, namely 29.9 ± 1.9, 31.0 ± 0.3, 35.4 ± 0.4, 46.7 ± 1.5, and 115.7 ± 3.2 g/7 mm for 0, 0.1, 0.2, 0.3 and 0.4%, respectively. Sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS-PAGE showed that addition of ascorbic acid drove formation odfdisulphide bond in the myosin heavy chain (MHC and other myofirillar proteins, resulting in the development of a strong three dimensions structure I myofibril gel as shown by microscopic structure.

  20. Countercurrent Chromatographic Separation of Lipophilic Ascorbic Acid Derivatives and Extract from Kadsura Coccinea Using Hydrophobic Organic-Aqueous Two-Phase Solvent Systems

    OpenAIRE

    Shinomiya, Kazufusa; Li, Heran; Kitanaka, Susumu; Ito, Yoichiro

    2009-01-01

    Countercurrent chromatographic (CCC) separation of lipophilic ascorbic acid derivatives and the crude extract from Kadsura Coccinea was performed using the type-J multilayer coil planet centrifuge with a hydrophobic organic-aqueous two-phase solvent system composed of n-hexane/ethyl acetate/ethanol/aqueous 0.1% trifluoroacetic acid at the volume ratio of (5 : 5 : 6 : 2). The lipophilic ascorbic acid derivatives were separated in the order of L-ascrobyl 2,6-dibutyrate, L-ascorbyl 6-palmitate a...

  1. L-ascorbic acid determination in pharmaceutical formulations using a biosensor based on carbon paste modified with crude extract of zucchini (Cucurbita pepo)

    OpenAIRE

    Fatibello-Filho Orlando; Vieira Iolanda da C.

    2000-01-01

    A biosensor based on carbon paste modified with crude extract of zucchini (Cucurbita pepo) as a source of peroxidase is proposed for determining L-ascorbic acid in pharmaceutical formulations. This enzyme in the presence of hydrogen peroxide catalyses the oxidation of hydroquinone to p-quinone whose electrochemical reduction back to hydroquinone was obtained at peak potential of -0.14V. Thus, when L-ascorbic acid is added to the solution, this acid can reduce chemically p-quinone to hydroquin...

  2. Effect of the ascorbic acid treatment on the NADHd-positive myenteric neurons of diabetic rats proximal colon

    Scientific Electronic Library Online (English)

    Jacqueline Nelisis, Zanoni; Renata Virginia Fernandes, Pereira; Priscila de, Freitas.

    2007-01-01

    Full Text Available SciELO Brazil | Language: English Abstract in portuguese O efeito do ácido ascórbico sobre neurônios mioentéricos do colo proximal de ratos diabéticos foi avaliado. Quinze ratos com 90 dias foram divididos nos grupos: controle, diabéticos e diabéticos tratados com ácido ascórbico (DA). Após 120 dias de tratamento diário com ácido ascórbico os segmentos in [...] testinais foram submetidos à técnica histoquímica NADH-diaforase (NADHd). A densidade neuronal, em uma área de 14,11 mm² para cada segmento, e o perfil do corpo celular de neurônios (500 neurônios/grupo) foram avaliados. O grupo DA apresentou maior densidade neuronal (33.4 %) em relação aos animais diabéticos (p Abstract in english The aim of this work was to study the effect of the ascorbic acid on the myenteric neurons of diabetic rats proximal colon. Fifteen rats (90 days old) were divided into three groups: control, untreated diabetic and treated diabetic with ascorbic acid (DA). After 120 days of daily treatment with asco [...] rbic acid, the intestinal segments were submitted to the NADH-diaphorase (NADHd) histochemistry technique to expose the myenteric neurons. The group DA showed a higher neuronal density (33.4 %) when compared to the untreated diabetic animals (p

  3. Radioprotective effect of ascorbic acid on cytological changes induced by exposing fertile eggs to different doses of gamma rays in chicken embryos

    International Nuclear Information System (INIS)

    Acute radiation syndrome that develops after exposure to ionizing radiation is mainly caused by the impairment of cell division which is of vital importance for all biological systems. DNA is susceptible to damage by reactive oxygen species (ROS) which are produced via exposure to ionizing radiation and expressed by cellular alterations and chromosomal damage. The present study showed that the irradiated group of chick embryo revealed linearity of damaging effect with increasing dose level from 50 rad to 150 rad. The antioxidant ascorbic acid (vitamin C) could acts as a first defense against DNA oxidative stress. The present work clarified the extent to which the natural compound ascorbic acid could antagonist the incorporated radionuclide impact induced by radiation and effect genomic stability of embryonic cells. The obtained data revealed that injection of ascorbic acid(100 mug/ egg) prior to radiation exposure induced significant reduction (P<0.05) in the frequency of total aberrant

  4. Furan occurrence in starchy food model systems processed at high temperatures: effect of ascorbic acid and heating conditions.

    Science.gov (United States)

    Mariotti, María; Granby, Kit; Fromberg, Arvid; Risum, Jørgen; Agosin, Eduardo; Pedreschi, Franco

    2012-10-10

    Furan, a potential carcinogen, has been detected in highly consumed starchy foods, such as bread and snacks; however, research on furan generation in these food matrixes has not been undertaken, thus far. The present study explored the effect of ascorbic acid addition and cooking methods (frying and baking) over furan occurrence and its relation with the non-enzymatic browning in a wheat flour starchy food model system. Results showed that furan generation significantly increased in the presence of ascorbic acid after 7 min of heating (p baked products. Additionally, the furan content in fried products increased with the increase of the oil uptake levels. As for Maillard reactions, in general, the furan level in all samples linearly correlated with their degree of non-enzymatic browning, represented by L* and a* color parameters (e.g., wheat flour baked samples showed a R(2) of 0.88 and 0.87 for L* and a*, respectively), when the sample moisture content decreased during heating. PMID:22985355

  5. Furan Occurrence in Starchy Food Model Systems Processed at High Temperatures: Effect of Ascorbic Acid and Heating Conditions

    DEFF Research Database (Denmark)

    Mariotti, Mari?a; Granby, Kit

    2012-01-01

    Furan, a potential carcinogen, has been detected in highly consumed starchy foods, such as bread and snacks; however, research on furan generation in these food matrixes has not been undertaken, thus far. The present study explored the effect of ascorbic acid addition and cooking methods (frying and baking) over furan occurrence and its relation with the non-enzymatic browning in a wheat flour starchy food model system. Results showed that furan generation significantly increased in the presence of ascorbic acid after 7 min of heating (p <0.05). The strongest effect was observed for baked products. Additionally, the furan content in fried products increased with the increase of the oil uptake levels. As for Maillard reactions, in general, the furan level in all samples linearly correlated with their degree of non-enzymatic browning, represented by L* and a* color parameters (e.g., wheat flour baked samples showed a R2 of 0.88 and 0.87 for L* and a*, respectively), when the sample moisture content decreased during heating.

  6. Effects of ascorbic acid on PVS2 cryopreservation of Dendrobium Bobby Messina's PLBs supported with SEM analysis.

    Science.gov (United States)

    Antony, Jessica Jeyanthi James; Keng, Chan Lai; Mahmood, Maziah; Subramaniam, Sreeramanan

    2013-09-01

    Regrowth of the cryopreserved protocorm-like bodies (PLBs) of Dendrobium Bobby Messina was assessed based on the plant vitrification solution 2 (PVS2) optimisation conditions. The optimized protocol obtained based on TTC spectrophotometrical analysis and growth recovery were 3-4 mm of PLBs size precultured in 0.2 M sucrose for 1 day, treated with a mixture of 2 M glycerol and 0.4 M sucrose supplemented with half-strength liquid MS media at 25 °C for 20 min and subsequently dehydrated with PVS2 at 0 °C for 20 min prior to storage in liquid nitrogen. Following rapid warming in a water bath at 40 °C for 90 s, PLBs were treated with unloading solution containing half-strength liquid MS media supplemented with 1.2 M sucrose. Subsequently, the PLBs were cultured on half-strength semi-solid MS media supplemented with 2 % (w/v) sucrose without any growth regulators and resulted in 40 % growth recovery. In addition, ascorbic acid treatment was used to evaluate the regeneration process of cryopreserved PLBs. However, growth recovery rates of non-cryopreserved and cryopreserved PLBs were 30 and 10 % when 0.6 mM ascorbic acid was added. Scanning electron microscopy analysis indicates that there are not much damages observed on both cryopreserved and non-cryopreserved PLBs in comparison to PLBs stock culture. PMID:23832189

  7. Role of C-terminal acidic cluster in stabilization of heme spin state of ascorbate peroxidase from Leishmania major.

    Science.gov (United States)

    Yadav, Rajesh K; Dolai, Subhankar; Pal, Swati; Adak, Subrata

    2010-03-15

    Architecture of hemoprotein is solely responsible for different nature of heme coordination. Here we report that substitution of the acidic surface residue Glu226 to Ala in ascorbate peroxidase from Leishmania major alters the 5 coordinate high spin (5cHS) to a 6 coordinate low spin (6cLS) form at pH 7.5. Using UV-visible spectrophotometry, we show that the sixth ligand of heme in Glu226Ala at pH 7.5 is hydroxo. When the pH is decreased to 5.5, a new species of Glu226Ala appeared that had a spectrum characteristic of a 6cHS derivative. Stopped flow spectrophotometric techniques revealed that characteristics of Compound I was not seen in the Glu226Ala in presence of H(2)O(2). Similarly guaiacol, ascorbate and ferrocytochrome c oxidation rate was 10(3) orders less for the Glu226Ala mutants compared to the wild type. These data suggested that surface acidic residue Glu226 might play role in proper maintenance of active site conformation. PMID:20060805

  8. Cottonseed meal, dehydrated grass and ascorbic acid as dietary factors preventing toxicity of vanadium for the chick

    Energy Technology Data Exchange (ETDEWEB)

    Berg, L.R.; Lawrence, W.W.

    1971-01-01

    Studies have been conducted which show that the replacement of 5% sucrose in a sucrose-fish meal diet for chicks with degossypolized cottonseed meal prevents the toxicity of 20 ppm added vanadium. The addition of 5% dehydrated grass to the same ration markedly reduced the toxicity symptoms. No such reduction in vanadium toxicity resulted when soybean meal, corn gluten meal, meat meal, fish meal, casein, isolated soybean protein, zein or wheat gluten were added to the ration. No evidence was found that the gossypol remaining in the cottonseed meal was the detoxifying agent. The addition of 0.25 to 0.50% ascorbic acid to the sucrose-fish meal basal ration prevented the toxic symptoms resulting from the addition of 20 ppm vanadium derived from HN/sub 4/VO/sub 3/. The vanadium derived from VOSO/sub 4/ and VOCl/sub 2/ (vanadium valence 4) was as toxic as vanadium derived from HN/sub 4/VO/sub 3/ (V = valence 5). This leads one to question that the action of ascorbic acid in reducing vanadium toxicity is through its property of a reducing agent which might change the vanadium in VH/sub 4/VO/sub 3/ to a lower valence, presumably less toxic.

  9. Protective effect of ascorbic acid on netilmicin-induced lipid profile and peroxidation parameters in rabbit blood plasma.

    Science.gov (United States)

    Devbhuti, Pritesh; Sikdar, Debasis; Saha, Achintya; Sengupta, Chandana

    2011-01-01

    A drug may cause alteration in blood-lipid profile and induce lipid peroxidation phenomena on administration in the body. Antioxidant may play beneficial role to control the negative alteration in lipid profile and lipid peroxidation. In view of this context, the present in vivo study was carried out to evaluate the role of ascorbic acid as antioxidant on netilmicin-induced alteration of blood lipid profile and peroxidation parameters. Rabbits were used as experimental animals and blood was collected to estimate blood-lipid profiles, such as total cholesterol (TCh), high density lipoprotein cholesterol (HDL-Ch), low density lipoprotein cholesterol (LDL-Ch), very low density lipoprotein cholesterol (VLDL-Ch), triglycerides (Tg), phospholipids (PL), and total lipids (TL), as well as peroxidation parameters, such as malondialdehyde (MDA), 4-hydroxy-2-nonenal (HNE), reduced glutathione (GSH) and nitric oxide (NO). The results revealed that netilmicin caused significant enhancement of MDA, HNE, TCh, LDL-Ch, VLDL-Ch, Tg levels and reduction in GSH, NO, HDL-Ch, PL, TL levels. On co-administration, ascorbic acid was found to be effective in reducing netilmicin-induced negative alterations of the above parameters. PMID:21485697

  10. Column chromatographic separation of thorium(IV) from ascorbic acid medium using poly-(dibenzo-18-crown-6)

    International Nuclear Information System (INIS)

    A simple separation method has been developed for thorium(IV) using poly-(dibenzo-18-crown-6) and column chromatography. The separation was carried out from ascorbic acid medium. The adsorption of thorium(IV) was quantitative from 0.001-0.01M ascorbic acid. The elution of thorium(IV) was quantitative with 4.0-8.0M HCl, 3.0-6.0M HClO4, 4.0-8.0M H2SO4 and 1.0-8.0M HBr. The capacity of poly-(dibenzo-18-crown-6) for thorium(IV) was found to be 1.379 ± 0.01 m x mol/g of crown polymer. Thorium(IV) was separated from a number of cations in binary as well as in multicomponent mixtures. The method was extended to the determination of thorium in monazite sand. It is possible to separate and determine 5 ppm of thorium(IV) by this method. The method is very simple, rapid, selective and has good reproducibility (approximately ±2%). (author)

  11. ESR identification of ?-irradiated redoxon and determination of ESR parameters of radicals produced in irradiated ascorbic acid

    International Nuclear Information System (INIS)

    In the present work, electron spin resonance (ESR) identification of irradiated redoxon and its potential use as a normal and/or accidental dosimetric material were investigated in details. The ground redoxon samples exhibited a single weak resonance line of peak-to-peak width ?Hpp = 0.9 mT appearing at g = 2.0057. ?-Radiation produced many resonance lines beside four different intense lines (denoted as I1, I2, I3 and I4) of different spectral features in the studied dose range of 2.5-25 kGy. Experimental dose-response curves associated with I1, I2, I3 and I4 resonance lines were found to follow an exponential function. From stability and kinetic studies at room and above room temperatures it was concluded that radicals contributing to I3 and I4 resonance lines were more stable than the radical species contributing to I1 and I2 resonance lines. Simulation calculations based on the room temperature ESR intensity data of an ascorbic acid (active ingredient of redoxon) sample irradiated at 10 kGy was performed to determine the structure and spectral parameters of the radiation-induced radical species involved in the formation of experimental ESR spectrum of ascorbic acid. The contributions of these species to the ESR spectrum of irradiated redoxon were discussed

  12. D-glucosone and L-sorbosone as putative intermediates in the biosynthesis of L-ascorbic acid in plants

    International Nuclear Information System (INIS)

    In plants, biosynthesis of L-ascorbic acid (AA) from D-glucose (glc) proceeds without carbon chain inversion. This requires oxidation of C1 and C2, and epimerization at C5. Neither sequence of reactions nor enzymes involved is yet known. To examine the overall reaction the authors fed D-[6-14C]glucosone to bean seedlings. It was converted to AA as effectively as [6-14C]glc with virtually no redistribution of label into the opposite terminal carbon. In other studies, a NADP-dependent L-sorbosone dehydrogenase that synthesized AA was isolated from bean and spinach leaves. Partial purification by precipitation at 45-55% (NH4)2SO4, fractionation on DEAE cellulose, and molecular sieving on Sephadex G-200 gave 30-fold purification. The enzyme was stable at -200C for several months. The apparent Km for sorbosone (0.9 mM NADP+) was 11.3+/-1.9 mM and for NADP+ (50 mM sorbosone) was 145+/-47 ?M. The relatively high Km's may reflect a two-step process or selection of a minor isomeric forms or sorbosone. A pathway (possibly involving phosphorylated intermediates) is suggested: D-Glucose?D-Glucosone?L-Sorbosone?L-Ascorbic acid

  13. Production of {sup 61}Cu using natural cobalt target and its separation using ascorbic acid and common anion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujata Saha; Chattopadhyay, Sankha; Barua, Luna [Radiopharmaceuticals Laboratory, Board of Radiation and Isotope Technology (BRIT), Variable Energy Cyclotron Centre (VECC), Kolkata 700064 (India); Das, Malay Kanti, E-mail: mkdas@vecc.gov.in [Radiopharmaceuticals Laboratory, Board of Radiation and Isotope Technology (BRIT), Variable Energy Cyclotron Centre (VECC), Kolkata 700064 (India)

    2012-02-15

    {sup 61}Cu was produced by {sup nat}Co({alpha}, xn){sup 61}Cu reaction. {sup 61}Cu production yield was 89.5 MBq/{mu}Ah (2.42 mCi/{mu}Ah) at the end of irradiation (EOI). A simple radiochemical separation method using anion exchange resin and ascorbic acid has been employed to separate the product radionuclide from inactive target material and co-produced non-isotopic impurities. The radiochemical separation yield was about 90%. Radiochemical purity of {sup 61}Cu was >99% 1 h after EOI. Final product was suitable for making complex with N{sub 2}S{sub 2} type of ligands. - Highlights: Black-Right-Pointing-Pointer High purity, no-carrier added {sup 61}Cu produced from natural cobalt target. Black-Right-Pointing-Pointer {sup 61}Cu separated from impurities using anion exchange resin and ascorbic acid. Black-Right-Pointing-Pointer {sup 61}Cu preparation was successfully used to label N{sub 2}S{sub 2}-type of ligand.

  14. Effect of gamma irradiation in presence of ascorbic acid on microbial composition and TBARS concentration of ground beef coated with an edible active coating

    International Nuclear Information System (INIS)

    The present study was conducted to evaluate the combined effect of gamma irradiation in presence of ascorbic acid on the microbiological characteristics and thiobarbituric acid-reactive substances (TBARS) concentration of ground beef coated with an edible coating, crosslinked by gamma irradiation. The medium fat ground beef patties (23% fat ) were divided into two separate treatment groups: (i) control (ground beef without additive), (ii) ground beef with 0.5% (w/w) ascorbic acid. Meat samples were irradiated at doses of 0, 1, 2, and 3 kGy and stored at 4±2 deg. C. The content of TBARS was evaluated. After 7 days of storage, Enterobacteriaceae, presumptive Staphylococcus aureus, presumptive Pseudomonas spp., Brochothrix thermosphacta and lactic acid bacteria were enumerated. Results showed that lactic acid bacteria and Br. thermosphacta were more resistant to irradiation than Enterobacteriaceae and Pseudomonas. The content in TBARS was stabilized during post-irradiation storage for samples containing ascorbic acid. Shelf life extension periods estimated on the basis of a limit level of 6 log CFU/g for APCs were 4, 7, and 10 days for samples irradiated at 1, 2, and 3 kGy, respectively. However, the incorporation of ascorbic acid in ground beef did not improve significantly (p>0.05) the inhibitory effect of gamma irradiation

  15. Rapid and specific spectrophotometric and RP-HPLC methods for the determination of ascorbic acid in fruits juices and in human plasma

    International Nuclear Information System (INIS)

    Ascorbic acid (AA) is one of the most important water soluble vitamin in the human diet, present naturally in a wide range of foods, especially fruits and vegetables. The objective of this study was to develop a rapid, sensitive and specific method for the determination of ascorbic acid (vitamin C) from a variety of sources like fresh fruits or from human plasma using spectrophotometric technique or by RP-HPLC. Initially, estimation of vitamin C was carried out spectrophotometrically as UV spectroscopy is a trusted technique to monitor small quantities of drugs and vitamins. The assay was linear over the concentration range of 0.05-100 mi cro g/mL/sup -I/. In the second procedure, we attempted to separate and quantitate ascorbic acid from fruit juices as well as from human plasma by RP-HPLC with UV detection. This has been possible because of the diversity of columns and conditions of analysis available. Chromatographic separation was successfully achieved on a pre-packed Kromasil 100, C/sub 18/ (5 macro m 25 x 0.46) column using acetonitrile water (60:40; v/v) as mobile phase at a flow rate of 0.75 mL/sup -min/ and effluent monitored at 265 nm. The assay was also linear over the concentration range of 0.05-100 micro g/mL/sub -1/, with recovery ranging from 99.0-100.0 % and intra and inter day CV <3 % when applied to the analysis of ascorbic acid from fruit juice available in Pakistan at the time of study Grape fruit, malta, mosami, sweetlemon, fruiter, lemon, lime, cosami, sweetlemon, fruiter, lemon, lime, custard apple, orange, lemon, guava and papaya juice were found to be very rich in as ascorbic acid, while chikoo, pear, apricot, peach, carrot and some other fruits were found to be poor sources of ascorbic acid. (author)

  16. Determinação espectrofotométrica de ácido ascórbico em fármacos empregando amostragem binária em fluxo Spectrophotometric determination of ascorbic acid in drugs employing binary sampling in flow system

    OpenAIRE

    Paim, Ana Paula S.; Kronka, Eloisa Ap M.; Reis, Boaventura F.; Mauro Korn

    1998-01-01

    A flow system procedure for spectrophotometric determination of ascorbic acid in drugs based on [Fe3+(SCN-)n]+3-n complex decomposition by reduction is described. The flow network was constituted by a set of three-way solenoid valves, controlled by a microcomputer running a software wrote in QuickBasic 4.5 language. The feasibility of the procedure was ascertained by determining ascorbic acid in drug samples with mass ranging from 0.0018 up to 0.0180 g. The results showed an agreement of abou...

  17. AN AUTOMATED METHOD FOR DETERMINATION OF ASCORBIC ACID IN URINE BY FLOW INJECTION CHEMILUMINESCENCE COUPLING WITH ON-LINE REMOVAL OF INTERFERENCE

    OpenAIRE

    LONGFEI CAI; CHUNXIU XU

    2011-01-01

    A simple and automated method for determination of ascorbic acid (AA) in complex samples by flow injection chemiluminescence (FI-CL) was presented. It is based on the inhibitory effect of ascorbic acid on the chemiluminescence reaction between luminol and hydrogen peroxide in the flow system. A home-made micro column of cation exchange resin was adapted to the FI manifold to achieve on-line removal of interference. This method was used to determine the AA content in urine samples with a detec...

  18. EVALUATION OF ANTIPEROXIDATIVE POTENTIAL OF ASCORBIC ACID ON BUSULFAN-INDUCED LIPID PEROXIDATION USING 4-HYDROXY-2-NONENAL AND NITRIC OXIDE AS MODEL MARKERS

    Directory of Open Access Journals (Sweden)

    Supratim Ray

    2012-03-01

    Full Text Available The study was designed with an aim to evaluate the antiperoxidative potential of ascorbic acid on busulfan-induced lipid peroxidation. The study was performed in vitro using goat liver as lipid source. This evaluation was done by measuring the 4-hydroxy-2-nonenal (4-HNE and nitric oxide (NO content of liver tissue homogenates as markers of lipid peroxidation. The study reveals the lipid peroxidation induction capacity of busulfan and the antiperoxidative potential of ascorbic acid on busulfan-induced lipid peroxidation.

  19. Effect of Food Supplementation by N and Ascorbic Acid on Larval Mortality of Silkworm (Bombyx mori L.)

    OpenAIRE

    Humayun Javed; Mubashir Hussain Gondal

    2002-01-01

    The study was carried out to determine the effect of 0.2 % N in combination with different doses of ascorbic acid (0.025, 0.075, 0.100, 0.125 and 0.150%) on larval growth and silk production of silk worm larvae (Bombyx mori L.). The larvae were fed on mulberry leaves treated with given doses of nitrogen and ascorbic acid throughout the larval period. It was observed that all the growth parameter were influenced by food supplementation. The larvae which were offered mulberry leaves treated wit...

  20. Micelle-mediated method for simultaneous determination of ascorbic acid and uric acid by differential pulse voltammetry

    Scientific Electronic Library Online (English)

    Alaécio P. dos, Reis; César R. T., Tarley; Lauro T., Kubota.

    1567-15-01

    Full Text Available SciELO Brazil | Language: English Abstract in portuguese O presente trabalho descreve uma metodologia analítica para determinação simultânea de ácido ascórbico (AA) e ácido úrico (AU) por voltametria de pulso diferencial empregando o surfactante catiônico cloreto de cetilpiridínio. Medidas voltamétricas de pulso diferencial realizadas em pH 7,0 revelaram [...] que o meio micelar catiônico permite separar em 282 mV os picos de oxidação de AA e AU na mesma solução, valor suficiente para determinar ambas as espécies simultaneamente. Como em pH 7,0 o AA está mais ionizado que o AU, sua atração eletrostática em direção às micelas catiônicas, formadas sobre a superfície do eletrodo de carbono vítreo, é maior; desta forma, promove a diminuição no sobrepotencial e o aumento na taxa de transferência de elétrons. Foram construídas curvas de calibração para AA e AU na faixa de concentração de 4,70 até 220 µmol L-1 e 0,50 até 110 µmol L-1. A metodologia proposta foi aplicada para a determinação de AA e AU em amostras de urina humana. Abstract in english The present work describes an analytical methodology for simultaneous determination of ascorbic acid (AA) and uric acid (UA) by differential pulse voltammetry employing the cationic surfactant, cetylpyridinium chloride. Differential pulse voltammetry measurements revealed that the cationic micellar [...] media may separate the oxidation peak potentials of AA and UA present in the same solution by about 282 mV, which is enough to determine both species simultaneously. As in pH 7.0 the AA is more ionized than UA, its electrostatic attraction towards the cationic micelles formed onto the surface of glassy carbon electrode is higher, therefore, promoting a decrease in the overpotential and increasing the electron transfer rate. Calibration curves to AA and UA in the concentration range from 4.70 up to 220 µmol L-1 and 0.50 up to 110 µmol L-1 were built. The proposed methodology was applied for the simultaneous determination of AA and UA in human urine samples.