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Sample records for ascorbic acid inhibits

  1. Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid.

    Science.gov (United States)

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

    2013-08-15

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

  2. Ascorbic Acid

    Science.gov (United States)

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

  3. Inhibition of free radical-induced erythrocyte hemolysis by 2-O-substituted ascorbic acid derivatives.

    Science.gov (United States)

    Takebayashi, Jun; Kaji, Hiroaki; Ichiyama, Kenji; Makino, Kazutaka; Gohda, Eiichi; Yamamoto, Itaru; Tai, Akihiro

    2007-10-15

    Inhibitory effects of 2-O-substituted ascorbic acid derivatives, ascorbic acid 2-glucoside (AA-2G), ascorbic acid 2-phosphate (AA-2P), and ascorbic acid 2-sulfate (AA-2S), on 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis of sheep erythrocytes were studied and were compared with those of ascorbic acid (AA) and other antioxidants. The order of the inhibition efficiency was AA-2S> or =Trolox=uric acid> or =AA-2P> or =AA-2G=AA>glutathione. Although the reactivity of the AA derivatives against AAPH-derived peroxyl radical (ROO(*)) was much lower than that of AA, the derivatives exerted equal or more potent protective effects on AAPH-induced hemolysis and membrane protein oxidation. In addition, the AA derivatives were found to react per se with ROO(*), not via AA as an intermediate. These findings suggest that secondary reactions between the AA derivative radical and ROO(*) play a part in hemolysis inhibition. Delayed addition of the AA derivatives after AAPH-induced oxidation of erythrocytes had already proceeded showed weaker inhibition of hemolysis compared to that of AA. These results suggest that the AA derivatives per se act as biologically effective antioxidants under moderate oxidative stress and that AA-2G and AA-2P may be able to act under severe oxidative stress after enzymatic conversion to AA in vivo. PMID:17854711

  4. Fat transforms ascorbic acid from inhibiting to promoting acid?catalysed N?nitrosation

    OpenAIRE

    Combet, E; Paterson, S.; Iijima, K; Winter, J; Mullen, W.; Crozier, A; Preston, T.; McColl, K.E.L.

    2007-01-01

    Background: The major potential site of acid nitrosation is the proximal stomach, an anatomical site prone to a rising incidence of metaplasia and adenocarcinoma. Nitrite, a pre-carcinogen present in saliva, can be converted to nitrosating species and N-nitroso compounds by acidification at low gastric pH in the presence of thiocyanate. Aims: To assess the effect of lipid and ascorbic acid on the nitrosative chemistry under conditions simulating the human proximal stomach. M...

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

    Science.gov (United States)

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

    2014-10-01

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

  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. Oxygen dependency of one-electron reactions generating ascorbate radicals and hydrogen peroxide from ascorbic acid.

    Science.gov (United States)

    Boatright, William L

    2016-04-01

    The effect of oxygen on the two separate one-electron reactions involved in the oxidation of ascorbic acid was investigated. The rate of ascorbate radical (Asc(-)) formation (and stability) was strongly dependent on the presence of oxygen. A product of ascorbic acid oxidation was measurable levels of hydrogen peroxide, as high as 32.5?M from 100?M ascorbic acid. Evidence for a feedback mechanism where hydrogen peroxide generated during the oxidation of ascorbic acid accelerates further oxidation of ascorbic acid is also presented. The second one-electron oxidation reaction of ascorbic acid leading to the disappearance of Asc(-) was also strongly inhibited in samples flushed with argon. In the range of 0.05-1.2mM ascorbic acid, maximum levels of measurable hydrogen peroxide were achieved with an initial concentration of 0.2mM ascorbic acid. Hydrogen peroxide generation was greatly diminished at ascorbic acid levels of 0.8mM or above. PMID:26593628

  9. Browning inhibition mechanisms by cysteine, ascorbic acid and citric acid, and identifying PPO-catechol-cysteine reaction products.

    Science.gov (United States)

    Ali, Hussein M; El-Gizawy, Ahmed M; El-Bassiouny, Rawia E I; Saleh, Mahmoud A

    2015-06-01

    The titled compounds were examined as PPO inhibitors and antibrowning agents; their various mechanisms were investigated and discussed. All compounds reduced significantly both the browning process and PPO activity. Browning index gave strong correlation with PPO activity (r(2)?=?0.96, n?=?19) indicating that the browning process is mainly enzymatic. Ascorbic acid could reduce the formed quinone instantly to the original substrate (catechol) at high concentration (>1.5 %) while at lower concentrations acted as competitive inhibitor (KI?=?0.256?±?0.067 mM). Cysteine, at higher concentrations (?1.0 %), reacted with the resulted quinone to give a colorless products while at the low concentrations, cysteine worked as competitive inhibitor (KI?=?1.113?±?0.176 mM). Citric acid acted only as PPO non-competitive inhibitor with KI?=?2.074?±?0.363 mM. The products of PPO-catechole-cysteine reaction could be separation and identification by LC-ESI-MS. Results indicated that the product of the enzymatic oxidation of catechol, quinone, undergoes two successive nucleophilic attacks by cysteine thiol group. Cysteine was condensed with the resulted mono and dithiocatechols to form peptide side chains. PMID:26028748

  10. 21 CFR 582.5013 - Ascorbic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ascorbic acid. 582.5013 Section 582.5013 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids listed in this subpart may...

  11. 21 CFR 582.3013 - Ascorbic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ascorbic acid. 582.3013 Section 582.3013 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... Ascorbic acid. (a) Product. Ascorbic acid. (b) Conditions of use. This substance is generally recognized...

  12. 21 CFR 182.8013 - Ascorbic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ascorbic acid. 182.8013 Section 182.8013 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8013 Ascorbic acid. (a) Product. Ascorbic acid. (b) Conditions of use. This substance is generally recognized as safe when used...

  13. Drug Nanoparticle Formulation Using Ascorbic Acid Derivatives

    OpenAIRE

    Kunikazu Moribe; Waree Limwikrant; Kenjirou Higashi; Keiji Yamamoto

    2011-01-01

    Drug nanoparticle formulation using ascorbic acid derivatives and its therapeutic uses have recently been introduced. Hydrophilic ascorbic acid derivatives such as ascorbyl glycoside have been used not only as antioxidants but also as food and pharmaceutical excipients. In addition to drug solubilization, drug nanoparticle formation was observed using ascorbyl glycoside. Hydrophobic ascorbic acid derivatives such as ascorbyl mono- and di-n-alkyl fatty acid derivatives are used either as drugs...

  14. 21 CFR 182.3013 - Ascorbic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ascorbic acid. 182.3013 Section 182.3013 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... acid. (a) Product. Ascorbic acid. (b) Conditions of use. This substance is generally recognized as...

  15. Ascorbic acid mitigation of water stress-inhibition of root growth in association with oxidative defense in tall fescue (Festuca arundinacea Schreb.)

    Science.gov (United States)

    Xu, Yi; Xu, Qian; Huang, Bingru

    2015-01-01

    Root growth inhibition by water stress may be related to oxidative damages. The objectives of this study were to determine whether exogenous application of ascorbic acid (ASA) could mitigate root growth decline due to water stress and whether ASA effects on root growth could be regulated through activating non-enzymatic or enzymatic antioxidant systems in perennial grass species. Tall fescue (Festuca arundinacea Schreb. cv. “K-31”) plants were grown in nutrient solution, and polyethylene glycol (PEG)-8000 was added into the solution to induce water stress. For exogenous ASA treatment, ASA (5 mM) was added into the solution with or without PEG-8000. Plants treated with ASA under water stress showed significantly increased root growth rate, and those roots had significantly lower content of reactive oxygen species (ROS) (H2O2 and O2? content) than those without ASA treatment. Malondialdehyde content in root tips treated with ASA under water stress was also significantly reduced compared with those under water stress alone. In addition, free ascorbate and total ascorbate content were significantly higher in roots treated with ASA under water stress than those without ASA treatment. The enzymatic activities for ROS scavenging-related genes were not significantly altered by ASA treatment under water stress, while transcript abundances of genes encoding superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monohydroascorbate reductase showed significant decreases in the root elongation zone and significant increases in the root maturation zone treated with ASA under water stress. Transcripts of genes for expansins and xyloglucan endotransglycosylases showed increased abundances in ASA-treated root maturation zone under water stress, indicating that ASA could accelerated cell wall loosening and cell expansion. The results suggested that exogenous treatment of roots with ASA enhanced root elongation under water stress, which could be attributed by increasing non-enzymatic antioxidant production, suppressing ROS toxicity and up-regulating gene expression of cell-wall loosening proteins controlling cell expansion. PMID:26483821

  16. Ascorbic acid inhibits ferric nitrilotriacetate induction of ornithine decarboxylase, DNA synthesis, oxidative stress, and hepatotoxicity in rats.

    Science.gov (United States)

    Ansar, S; Iqbal, M

    2015-11-01

    Ascorbic acid (AA) is a naturally occurring phenolic compound with antioxidant properties used in food, cosmetics, and pharmaceutical products. In this study, the effect of AA on ferric nitrilotriacetate (Fe-NTA)-induced hepatotoxicity in rats has been examined. Fe-NTA alone enhances ornithine decarboxylase activity to 4.5-fold and tritiated thymidine incorporation in DNA to 3.6-fold in livers compared with the corresponding saline-treated controls. The enhanced ornithine decarboxylase activity and DNA synthesis showed a reduction to 3.02- and 1.88-fold, respectively, at a higher dose of 2 mg AA per day per animal, compared with the Fe-NTA-treated groups. Fe-NTA treatment also enhanced the hepatic microsomal lipid peroxidation to 1.7-fold compared to saline-treated controls. These changes were reversed significantly in animals receiving pretreatment of AA. The present data shows that AA can reciprocate the toxic effects of Fe-NTA and can serve as a potent chemopreventive agent to suppress oxidant-induced tissue injury and hepatotoxicity in rats. PMID:23863956

  17. 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

  18. Sensitization of Salmonella typhi towards gamma-radiation by ascorbic acid

    International Nuclear Information System (INIS)

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

  19. Higher transcription levels in ascorbic acid biosynthetic and recycling genes were associated with higher ascorbic acid accumulation in blueberry.

    Science.gov (United States)

    Liu, Fenghong; Wang, Lei; Gu, Liang; Zhao, Wei; Su, Hongyan; Cheng, Xianhao

    2015-12-01

    In our preliminary study, the ripe fruits of two highbush blueberry (Vaccinium corymbosum L.) cultivars, cv 'Berkeley' and cv 'Bluecrop', were found to contain different levels of ascorbic acid. However, factors responsible for these differences are still unknown. In the present study, ascorbic acid content in fruits was compared with expression profiles of ascorbic acid biosynthetic and recycling genes between 'Bluecrop' and 'Berkeley' cultivars. The results indicated that the l-galactose pathway was the predominant route of ascorbic acid biosynthesis in blueberry fruits. Moreover, higher expression levels of the ascorbic acid biosynthetic genes GME, GGP, and GLDH, as well as the recycling genes MDHAR and DHAR, were associated with higher ascorbic acid content in 'Bluecrop' compared with 'Berkeley', which indicated that a higher efficiency ascorbic acid biosynthesis and regeneration was likely to be responsible for the higher ascorbic acid accumulation in 'Bluecrop'. PMID:26041210

  20. Transglucosylation of ascorbic acid to ascorbic acid 2-glucoside by a recombinant sucrose phosphorylase from Bifidobacterium longum.

    Science.gov (United States)

    Kwon, Taeyeon; Kim, Cheong Tae; Lee, Jong-Hoon

    2007-04-01

    A novel transglycosylation reaction from sucrose to L-ascorbic acid by a recombinant sucrose phosphorylase from Bifidobacterium longum was used to produce a stable L-ascorbic acid derivative. The major product was detected by HPLC, and confirmed to be 2-O-alpha-D-glucopyranosyl-L-ascorbic acid by LC-MS/MS analysis. PMID:17216298

  1. Ascorbic acid enhances the inhibitory effect of aspirin on neuronal cyclooxygenase-2-mediated prostaglandin E2 production

    OpenAIRE

    Candelario-Jalil, E.; Akundi, R. S.; Bhatia, H. S.; Lieb, K.; Appel, K; Munoz, E; Hull, M.; Fiebich, B. L.

    2007-01-01

    In the present study, we show that ascorbic acid dose-dependently inhibited interleukin-1beta (IL-1beta)-mediated PGE2 synthesis in the human neuronal cell line, SK-N-SH. Furthermore, in combination with aspirin, ascorbic acid augmented the inhibitory effect of aspirin on PGE2 synthesis. However, ascorbic acid had no synergistic effect along with other COX inhibitors (SC-58125 and indomethacin). The inhibition of IL-1beta-mediated PGE2 synthesis by ascorbic acid was not due ...

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

    International Nuclear Information System (INIS)

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

  3. Supplementation of Ascorbic Acid in Weanling Horses Following Prolonged Transportation

    Directory of Open Access Journals (Sweden)

    Michelle Stives

    2012-04-01

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

  4. 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.

  5. 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)

  6. Ascorbic acid monoglucoside as antioxidant and radioprotector

    International Nuclear Information System (INIS)

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

  7. Heavy metals influence on ascorbic acid level

    Science.gov (United States)

    Kamaldinov, E. V.; Patrashkov, S. A.; Batenyeva, E. V.; Korotkevich, O. S.

    2003-05-01

    It is well known that heavy metals (HM) are extremely dangerous pollutants influencing to metabolism in animals' organisms. The vitamin C is one of the most important metabolites taking part in many biochemical processes. We studied the influence of main essential HM-Zn and Cu as well as the based supertoxical elements - Cd and Pd on ascorbic acid level in serum. The studies were carried out in Tulinskoe farm of Novosibirsk region. The objects of investigations were piglets (2 month after weaning) and 6-month pigs of Early Ripe Meat breed. The levels of HM in bristle were found by stripping voltammetric analysis using the TA-2 analyzer. Vitamin C content was determined by I.P. Kondrakhin (1985) method using 2,2-dipyridyl. The significant negative correlations between Pb, Cd content and vitamin C (-0.46 ± 0.18, -0.47 ± 0.19) in 6-month pigs were determined. The tendencies of negative correlation between all HM levels in hair and ascorbic acid level in plasma of piglets were revealed. Thus, the obtained correlations let us to suppose that all studied HM influence on 1-gulono-gamma-lactone oxidase and other vitamin C metabolism enzymes activity.

  8. Ascorbic acid supplements in patients receiving chronic peritoneal dialysis.

    Science.gov (United States)

    Shah, G M; Ross, E A; Sabo, A; Pichon, M; Bhagavan, H; Reynolds, R D

    1991-07-01

    Ascorbic acid supplements are commonly prescribed to patients with end-stage renal disease receiving peritoneal dialysis. To establish the need for ascorbic acid supplements, we evaluated seven chronic peritoneal dialysis patients during a supplement-free (phase I) period, and while receiving oral ascorbic acid (0.57 mmol/d [100 mg/d]) (phase II). Because of a proposed interaction with vitamin B6, patients were additionally supplemented with pyridoxine HCl (59.6 mumol/d [10 mg/d]) (phase III). Plasma levels and dialysate removal rates of total ascorbic acid and plasma pyridoxal-5-phosphate (PLP) were measured at the end of each phase. During phase I, plasma ascorbic acid levels (normal, 45 to 57 mumol/L [0.8 to 1.0 mg/dL]) declined slightly from 74 +/- 11 mumol/L (1.3 +/- 0.2 mg/dL) to 62 +/- 11 mumol/L (1.1 +/- 0.2 mg/dL) (P less than 0.02) at the end of the third week, and then remained stable to the end of the fourth week. Plasma ascorbic acid levels were no different in patients with or without residual renal function. With the addition of vitamin C supplements, plasma ascorbic acid levels increased by 45% of the baseline value at the end of phases II (P less than 0.001). The dialysate removal rate of ascorbic acid was 0.28 +/- 0.03 mmol/d (50 +/- 6 mg/d) at the end of phase I, and increased by 57% of the baseline value at the end of phases II (P less than 0.001). However, the peritoneal clearance of ascorbic acid remained unchanged during all phases the study. Pyridoxine depletion or repletion had no effect on plasma ascorbic acid levels (P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2063860

  9. Ascorbic acid contents of Pakistani fruits and vegetables.

    Science.gov (United States)

    Iqbal, M Perwaiz; Kazim, Syed Faraz; Mehboobali, Naseema

    2006-10-01

    Fresh fruits and vegetables are good sources of vitamin C which is known for its antioxidant and immune-enhancing effects. The objective of this study was to determine ascorbic acid (vitamin C) contents of regularly consumed fruits and vegetables available in Pakistani markets. Most commonly used fresh fruits and vegetables were homogenized in 5% trichloroacetic acid, and ascorbic acid contents in the extracts were determined using a spectrophotometric method. Banana, custard apple, orange, lemon, guava and papaya were found to be very rich in ascorbic acid. Among vegetables, capsicum (green sweet pepper), cauliflower, bittergourd, roundgourd, beetroot, spinach, cabbage and radish contained high concentrations of ascorbic acid. Chikoo, grapes, pear, apricot, peach, carrot, cucumber, lettuce and "kakri" were found to be poor sources of ascorbic acid. Several Pakistani fruits and vegetables (pear, melon, onion, sweet green pepper, spinach, cucumber) had ascorbic acid values similar to those reported by US Department of Agriculture in these fruits and vegetables in USA. However, wide differences in vitamin C contents were also observed in certain other fruits and vegetables from these two countries. This indicates that regional varieties of fruits and vegetables could vary in their ascorbic acid contents. Since subclinical deficiency of vitamin C appears to be quite common in developing countries like Pakistan, there is a need to develop awareness among masses to consume fresh fruits and vegetables with high contents of vitamin C. PMID:17105704

  10. 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.

  11. Regulation of collagen synthesis by ascorbic acid.

    OpenAIRE

    Murad, S; Grove, D.; Lindberg, K A; Reynolds, G.; Sivarajah, A; Pinnell, S R

    1981-01-01

    After prolonged exposure to ascorbate, collagen synthesis in cultured human skin fibroblasts increased approximately 8-fold with no significant change in synthesis of noncollagen protein. This effect of ascorbate appears to be unrelated to its cofactor function in collagen hydroxylation. The collagenous protein secreted in the absence of added ascorbate was normal in hydroxylysine but was mildly deficient in hydroxyproline. In parallel experiments, lysine hydroxylase (peptidyllysine, 2-oxoglu...

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

    Science.gov (United States)

    Chen, Hongxing; Gu, Zhengbiao

    2014-09-01

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

  13. Synthesis of New L-Ascorbic Ferulic Acid Hybrids

    OpenAIRE

    Sylvain Rault; Jean-Charles Lancelot; Marc-Antoine Bazin; Anne Sophie Voisin-Chiret

    2007-01-01

    A feasibility and chemical study of the coupling conditions of L-ascorbic acidwith ferulic acid derivatives are described on the basis of the known synergistic effects ofmixtures of various antioxidants. Novel L-ascorbic ferulic hybrids linked at the C-3hydroxyl group were prepared with the aim to protect the alcohol function and the enediolsystem.

  14. Synthesis of New L-Ascorbic Ferulic Acid Hybrids

    Directory of Open Access Journals (Sweden)

    Sylvain Rault

    2007-11-01

    Full Text Available A feasibility and chemical study of the coupling conditions of L-ascorbic acidwith ferulic acid derivatives are described on the basis of the known synergistic effects ofmixtures of various antioxidants. Novel L-ascorbic ferulic hybrids linked at the C-3hydroxyl group were prepared with the aim to protect the alcohol function and the enediolsystem.

  15. 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 eq...

  16. Ascorbic Acid Contents in Chili Peppers (Capsicum L.)

    OpenAIRE

    Owk ANIEL KUMAR; Sape SUBBA TATA

    2009-01-01

    The genus Capsicum commonly known as chili pepper is a major spice crop and is almost cosmopolitan in distribution. The nutritive value of chili pepper is largely determined by ascorbic acid content. The fruits at five ripening stages viz., (M1, M2, M3, M4 and M5) from seventeen cultivars of Capsicum annuum L and one cultivar of Capsicum frutescens L were analyzed for ascorbic acid content. Among eighteen genotypes the C. annuum var. IC: 119262(CA2) showed higher ascorbic acid content (mg/100...

  17. Ascorbic acid use in hyporesponders to Epoetin alfa.

    Science.gov (United States)

    Gibbs, M A

    2000-08-01

    I.v. ascorbic acid has been used in an effort to mobilize ferritin stores in hyporesponsive HD patients receiving Epoetin alfa. However, not all patients who respond to i.v. ascorbic acid therapy will have subsequent decline in feritin stores (Gastaldello et al., 1995; Tarng & Huang, 1998). Additionally, predicting those patients who will overcome their Epoetin alfa hyporesponsiveness remains unclear. Ascorbic acid's effect on hemosiderin deposits may be another possible mechanism to the increased Epoetin alfa response observed in some HD patients (Hemosiderin is a pathologic deposition of iron in tissues including the spleen, small intestine, and bone marrow). Although there are no well-controlled studies evaluating hemosiderin and i.v. ascorbic acid, it should be noted that subjects with scurvy often present with excessive iron deposits in the tissues, indicating the possible effects of ascorbic acid on hemosiderin metabolism (Bothwell et al., 1964). Ascorbic acid deficiency is often present in many HD patients due to its removal during dialysis and lack of dietary intake (Ponka & Kuhlback, 1983). It remains controversial whether oral ascorbic acid supplementation is indicated in patients receiving HD. Therefore, the Recommended Daily Allowance (RDA) of 60 mg/day should be advised (Makoff, 1999). I.v. ascorbic acid should be considered as a possible adjuvant to therapy in patients who are "iron-overloaded" and hyporesponsive to Epoetin alfa. Although the long-term effects of i.v. ascorbic acid on HD patients is unknown, the potential risk of secondary oxalosis should be considered (Costello, 1991; Pru, Eaton, & Kjellstrand, 1985). It may be necessary to monitor plasma oxalate levels if long-term therapy with i.v. ascorbic acid is used. Clinical studies have examined i.v. ascorbic acid doses from 300 mg-500 mg given up to TIW for a maximum duration of 12 weeks without any significant deleterious effects (Gastaldello et al., 1995; Tarng & Huang, 1998; Tarng et al., 1999). However, large-scale, prospective, and controlled trails are needed to determine the long-term safety and efficacy of i.v. ascorbic acid therapy in iron overloaded HD patients receiving Epoetin alfa. PMID:11276634

  18. Effect of Ascorbic Acid on Lipid Peroxidation Induced by Ceftazidime

    Directory of Open Access Journals (Sweden)

    Devbhuti P*,1

    2011-01-01

    Full Text Available Lipid peroxidation is the oxidative deterioration of polyunsaturated lipids which is a free radical related process and responsible for thedevelopment of many diseases and disorders like diabetes mellitus, hypertension, cancer etc. End products of lipid peroxidation aremalondialdehyde (MDA, 4-hydroxy-2-nonenal (4-HNE, etc. which are the ultimate mediator of toxicity. Antioxidants have the capability toinhibit lipid peroxidation. Keeping in mind this fact, the present in vitro study was carried out to evaluate lipid peroxidation induction potential of ceftazidime, a cephalosporin antibiotic and its suppression with ascorbic acid considering some laboratory markers of lipid peroxidation like MDA, 4-HNE and reduced glutathione (GSH. Goat liver was used as the lipid source. After treatment of the liver homogenate with drug and/or antioxidant the levels of 4-HNE, MDA and GSH were estimated in different samples at different hours of incubation. The results showed that the drug ceftazidime could significantly induce lipid peroxidation and the antioxidant ascorbic acid has the capability to inhibit ceftazidime-inducedlipid peroxidation.

  19. Radiation protection by ascorbic acid in sodium alginate solutions

    International Nuclear Information System (INIS)

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

  20. Radiation protection by ascorbic acid in sodium alginate solutions

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  1. Combined antioxidant (beta-carotene, alpha-tocopherol and ascorbic acid) supplementation increases the levels of lung retinoic acid and inhibits the activation of mitogen-activated protein kinase in the ferret lung cancer model.

    OpenAIRE

    Kim, Yuri; Chongviriyaphan, Nalinee; LIU, CHUN; RUSSELL Robert M.; Wang, Xiang-Dong

    2006-01-01

    Interactions among beta-carotene (BC), alpha-tocopherol (AT) and ascorbic acid (AA) led to the hypothesis that using a combination of these antioxidants could be more beneficial than using a single antioxidant alone, particularly against smoke-related lung cancer. In this investigation, we have conducted an animal study to determine whether combined BC, AT and AA supplementation (AOX) protects against 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung carcinogenesis in smoke-ex...

  2. Ascorbic acid metabolism in diabetes mellitus.

    Science.gov (United States)

    Pecoraro, R E; Chen, M S

    1987-01-01

    Competition for membrane transport between glucose and ascorbic acid (AA) has been shown in vitro in human lymphocytes, granulocytes, and fibroblasts. Therefore, we examined the effects of acute administration of i.v. glucose on AA levels in mononuclear (MNL) and polymorphonuclear leukocytes (PMN) and on leukocyte chemotaxis. Plasma glucose and AA, MNL AA, PMN AA, and chemotaxis by MNL and PMN were measured before and after i.v. glucose in fasted normal male volunteers. A decline in AA occurred in PMN as well as MNL, but decreases in AA induced acutely by transient hyperglycemia were not associated with changes in chemotaxis. However, under conditions of prolonged hyperglycemia maintained by a glucose clamp technique, significant changes (p less than 0.01) in chemotaxis by both PMN and MNL were observed after 210 and 240 min, with changes in chemotaxis to several chemoattractants significantly correlated with decreases in intracellular AA after 240 min (p less than 0.05). These results are consistent with the hypothesis that chronic hyperglycemia may be associated with intracellular deficits of leukocyte AA, an impaired acute inflammatory response, and altered susceptibility to infection and faulty wound repair in patients with diabetes. PMID:3475999

  3. Synergic interaction between ascorbic acid and antibiotics against Pseudomonas aeruginosa

    OpenAIRE

    Luciana Cursino; Edmar Chartone-Souza; Andréa Maria Amaral Nascimento

    2005-01-01

    Studies were carried out on in vitro combination of ascorbic acid (AA) with six antibiotics against 12 multi-resistant Pseudomonas aeruginosa isolates. Synergic activity was detected with AA chloramphenicol, kanamycin, streptomycin and tetracycline. Indifference was observed to any antibiotics and antagonism only for chloramphenicol. Results indicated that multiresistant P. aeruginosa was affected by combination of AA and antibiotics. Future research on ascorbic acid-antimicrobial interaction...

  4. 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...

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

    Science.gov (United States)

    PLASMID DNA DAMAGE CAOUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITINABSTRACT Both dimethylarsinic acid (DMA(V)) and dimethylarsinous acid (DMA(III)) release iron from human liver ferritin (HLF) with or without the presence of ascorbic acid. ...

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

    International Nuclear Information System (INIS)

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

  7. 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 ...

  8. 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.

  9. 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.

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

    OpenAIRE

    Vlad Artenie; Ioana-Anca Ieremie

    2008-01-01

    This paper present the influence of ascorbic acid and citric acid upon the mitotic division, and to the activity of some antioxidant enzymes to Picea abies (L.) Karst. The treatment was made through the germination of seeds in ascorbic acid and citric acid. We observed the stimulator or inhibitor effect of ascorbic acid and citric acid to the mitotic index and estimated the aberrations appearance. Comparative the control, the mitotic index increased at 0.1 % concentration ascorbic acid and de...

  11. 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 three ...

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

    Directory of Open Access Journals (Sweden)

    Anne-Christi Graeser

    2009-12-01

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

  13. Measurement of uric acid, ascorbic acid, and related metabolites in biological fluids.

    Science.gov (United States)

    Hatch, L L; Sevanian, A

    1984-05-01

    A rapid and quantitative method for the simultaneous measurement of uric acid, ascorbic acid, and related metabolites in biological fluids is described. This method makes use of anion-exchange extraction columns to isolate the desired compounds from a wide range of biological fluids, and anion-exchange HPLC with ultraviolet detection for their separation and measurement. By this procedure the contents of uric and ascorbic acids in human serum and urine were estimated. Furthermore, the oxidation of uric acid to allantoin and ascorbic acid to dehydroascorbic acid could be readily monitored. PMID:6742409

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

    OpenAIRE

    Anne-Christi Graeser; Katri Giller; Heike Wiegand; Luca Barella; Christine Boesch Saadatmandi; Gerald Rimbach

    2009-01-01

    Overproduction of reactive oxygen species and impaired antioxidant defence accompanied by chronic inflammatory processes may impair joint health. Pro-inflammatory cytokines such as interleukin-1? (IL-1?) and tumor necrosis factor alpha (TNF-?) stimulate the expression of metalloproteinases which degrade the extracellular matrix. Little is known regarding the potential synergistic effects of natural compounds such as ?-tocopherol (?-toc), ascorbic acid (AA) and selenium (Se) on oxidant induced...

  15. Ascorbic acid attenuates the pressor response to voluntary apnea in postmenopausal women.

    Science.gov (United States)

    Randolph, Brittney J; Patel, Hardikkumar M; Muller, Matthew D

    2015-04-01

    We recently demonstrated that postmenopausal women have an augmented blood pressure response to voluntary apnea compared to premenopausal women. Both obstructive sleep apnea (OSA) and healthy aging are associated with increased oxidative stress, which may impair cardiovascular function. Restoring physiological responses could have clinical relevance since transient surges in blood pressure are thought to be an important stimulus for end-organ damage in aging and disease. We tested the hypothesis that acute antioxidant infusion improves physiological responses to voluntary apnea in healthy postmenopausal women (n = 8, 64 ± 2 year). We measured beat-by-beat mean arterial pressure (MAP), heart rate (HR), and brachial artery blood flow velocity (BBFV, Doppler ultrasound) following intravenous infusion of normal saline and ascorbic acid (~3500 mg). Subjects performed maximal voluntary end-expiratory apneas and changes (?) from baseline were compared between infusions. The breath hold duration and oxygen saturation nadir were similar between saline (29 ± 6 sec, 94 ± 1%) and ascorbic acid (29 ± 5 sec, 94 ± 1%). Ascorbic acid attenuated the pressor response to voluntary apnea (?MAP: 6 ± 2 mmHg) as compared to saline (?MAP: 12 ± 2 mmHg, P = 0.034) and also attenuated forearm vasoconstriction (?BBFV: 4 ± 9 vs. -12 ± 7%, P = 0.049) but did not affect ?HR. We conclude that ascorbic acid lowers the blood pressure response to voluntary apnea in postmenopausal women by inhibiting vasoconstriction in the limb vasculature. Whether ascorbic acid has similar effects in OSA patients remains to be prospectively tested. PMID:25907792

  16. L-ascorbic acid- and L-ascorbic acid 2-glucoside accelerate in vivo liver regeneration and lower serum alanine aminotransaminase activity in 70% partially hepatectomized rats.

    Science.gov (United States)

    Kimura, Mitsutoshi; Moteki, Hajime; Uchida, Masaki; Natsume, Hideshi; Ogihara, Masahiko

    2014-01-01

    The effects of L-ascorbic acid and its stable analogue L-ascorbic acid 2-glucoside on the restoration of liver mass and recovery of liver function after 70% partial hepatectomy (PH), were compared with other natural vitamin C analogues in rats in vivo. L-Ascorbic acid (100 mg/kg/d, intraperitoneally (i.p.))- and L-ascorbic acid 2-glucoside (50 mg/kg/d, i.p.)-treated rats showed an approximately 1.3-fold increase in the ratio of liver weight (LW) to body weight (BW), when compared to saline (as control)-, L-dehydroascorbic acid (150 mg/kg/d, i.p.)- and D-isoascorbic acid (150 mg/kg/d, i.p.)-administrated rats on day 3 after PH. Accordingly, 5-bromo-2-deoxyuridine-labeling index in the regenerating liver was significantly higher in L-ascorbic acid- and L-ascorbic acid 2-glucoside-treated rats compared with saline-, L-dehydroascorbic acid and D-isoascorbic acid-treated rats on day 1. In control rats, liver-related serum alanine aminotransferase (ALT) activity was rapidly elevated on day 1, and then decreased to near pre-operative levels on day 5 following PH. L-Ascorbic acid and L-ascorbic acid 2-glucoside significantly lowered the serum ALT on day 1 after PH compared with saline-, L-dehydroascorbic acid- and D-isoascorbic acid-administered rats. These results demonstrate that L-ascorbic acid and L-ascorbic acid 2-glucoside significantly promote the regeneration of liver mass and function with full recovery after liver injury. PMID:24818255

  17. 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.

  18. 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.

  19. A Chronoamperometric Screen Printed Carbon Biosensor Based on Alkaline Phosphatase Inhibition for W(VI) Determination in Water, Using 2-Phospho-l-Ascorbic Acid Trisodium Salt as a Substrate

    OpenAIRE

    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 ...

  20. Effects of supplemental ascorbic acid on humeral immune response in broilers reared under heat-stress condition

    Directory of Open Access Journals (Sweden)

    Vahel J. A. Amedy,

    2011-07-01

    Full Text Available An experiment was conducted to evaluate the efficacy of supplemental ascorbic acid (Vitamin C on the haemagglutination inhibition (HI and enzyme linked immune sorbent assay (ELISA antibody titer of the commercial broiler chicks vaccinated against Newcastle disease (ND virus, reared under heat stress condition. A total of 420, one day-old broiler chicks were randomly divided into 4 groups and kept under elevated summer temperature and treated with four levels of added ascorbic acid i.e., 0 (control group, 200, 400, 600 mg/kg in diets for 28 days, from 21 to 49 days of experimental period. HI antibody titer and ELISA antibody titer against ND virus were significantly (P<0.05 higher at 600 mg/kg Vitamin C in the diet than the others treatments. Apparently, adding ascorbic acid at 600 mg/kg in the diet could improve humoral immunity in broilers reared under heat stress.

  1. Industrial production of L-ascorbic Acid (vitamin C) and D-isoascorbic acid.

    Science.gov (United States)

    Pappenberger, Günter; Hohmann, Hans-Peter

    2014-01-01

    L-ascorbic acid (vitamin C) was first isolated in 1928 and subsequently identified as the long-sought antiscorbutic factor. Industrially produced L-ascorbic acid is widely used in the feed, food, and pharmaceutical sector as nutritional supplement and preservative, making use of its antioxidative properties. Until recently, the Reichstein-Grüssner process, designed in 1933, was the main industrial route. Here, D-sorbitol is converted to L-ascorbic acid via 2-keto-L-gulonic acid (2KGA) as key intermediate, using a bio-oxidation with Gluconobacter oxydans and several chemical steps. Today, industrial production processes use additional bio-oxidation steps with Ketogulonicigenium vulgare as biocatalyst to convert D-sorbitol to the intermediate 2KGA without chemical steps. The enzymes involved are characterized by a broad substrate range, but remarkable regiospecificity. This puzzling specificity pattern can be understood from the preferences of these enyzmes for certain of the many isomeric structures which the carbohydrate substrates adopt in aqueous solution. Recently, novel enzymes were identified that generate L-ascorbic acid directly via oxidation of L-sorbosone, an intermediate of the bio-oxidation of D-sorbitol to 2KGA. This opens the possibility for a direct route from D-sorbitol to L-ascorbic acid, obviating the need for chemical rearrangement of 2KGA. Similar concepts for industrial processes apply for the production of D-isoascorbic acid, the C5 epimer of L-ascorbic acid. D-isoascorbic acid has the same conformation at C5 as D-glucose and can be derived more directly than L-ascorbic acid from this common carbohydrate feed stock. PMID:24258144

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

    Science.gov (United States)

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

    2000-11-10

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

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

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Timm Heinrich, Maike; Meyer, Anne S.

    2001-01-01

    The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil- water interface into the aqueous phase at all pH levels, but this effect of ascorbic acid was strongest at low pH (pH 3.8- 4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-18

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

  5. Ascorbic acid glucoside reduces neurotoxicity and glutathione depletion in mouse brain induced by nitrotriazole radiosensitazer

    Directory of Open Access Journals (Sweden)

    Nadezda V Cherdyntseva

    2013-01-01

    Full Text Available Aim: To investigate the potential of the anti-oxidant ascorbic acid glucoside (AA-2G to modulate neurotoxicity induced by high doses of nitrotriazole radiosensitizer. Materials and Methods: Male and female C56Bl/6xCBA hybrid mice aged 8-14 weeks (weight 18-24 g were used. Nitrotriazole drug radiosensitizer sanazole at a high dose of 2, 1 g/kg was per os administered to induce neurotoxicity at mice. Ascorbic acid glucoside was given 30 min before the sanazole administration. Serum ascorbic acid, brain glutathione level, as well as behavioral performance using open field apparatus were measured. Results: Administration of high (non-therapeutic doses of the nitrotriazole drug sanazole results in neurotoxicity in mice as evidenced from behavioral performance, emotional activity and depletion of the cellular antioxidant, glutathione, in the brain. The serum levels of ascorbic acid was also found reduced in high dose sanazole treated animals. Per os administration of ascorbic acid glucoside significantly reduced the neurotoxicity. This effect was associated with the prevention of glutathione depletion in mouse brain and restoring the ascorbic acid level in serum. Conclusion: Administration of ascorbic acid glucoside, but not ascorbic acid, before sanazole administration protected from sanazole-induced neurotoxicity by preventing the decrease in the brain reduced glutathione level and providing high level of ascorbic acid in plasma.

  6. Measurement of binding of ascorbic acid to myrosinase by rate of dialysis

    International Nuclear Information System (INIS)

    The activation mechanism of myrosinase by L-ascorbic acid depends on the slight conformational change of enzyme protein induced by ascorbic acid. Ascorbic acid binds to enzyme like Michaelis-complex, and then the value of Km had been evaluated to be 1 x 10-3M. The authors determined the binding constant and the number of binding sites using dialysis rate technique. Rate dialysis was carried out with a dialysis cell, and the ordinary cellophane tubing membrane was used. (14C)- ascorbic acid was added, and counted by liquid scintillation counting. By the time course of two dialysis rate measurement with and without enzyme. The concentrations of free and bound ascorbic acids were counted. From the results, the enzyme was activated to the maximum level at 10-3M of ascorbic acid, and four molecules of ascorbic acid bound to the enzyme on Kd=0.1x10-4M. However, when more than 4 molecules of L-ascorbic acid bound to the enzyme, Kd increased to 0.9x10-4M, and L-ascorbic acid acted as an inhibitor. (Kubatake, H.)

  7. 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 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

  8. 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)

  9. 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

  10. Effect of ascorbic acid on blood oxidative stress in experimental chronic arsenicosis in rodents.

    Science.gov (United States)

    Rana, Tanmoy; Bera, Asit Kumar; Das, Subhashree; Pan, Diganta; Bandyopadhyay, Subhasish; Bhattacharya, Debasis; De, Sumanta; Sikdar, Sourav; Das, Subrata Kumar

    2010-04-01

    Ascorbic acid is a sugar acid and an essential vital food nutrient found mainly in fruits and vegetables. The purpose of this study was to investigate the effects of ascorbic acid against arsenic induced oxidative stress in blood of rat. In rat, treatment with ascorbic acid prevented the increased serum enzymatic activity of AST, ALT, ALP, ACP and LDH. In addition, treatment with ascorbic acid prevented elevated production of LPO, PC and NO and restored the depletion of reduced SOD and CAT activities. Interestingly, ascorbic acid markedly upregulated lymphocytes relative mRNA expression of lymphocytes SOD2 gene corresponding to GAPDH, house keeping candidate gene in arsenic-treated rat, which might provide anti-oxidative activity in the blood. PMID:20122981

  11. Glycation by ascorbic acid oxidation products leads to the aggregation of lens proteins.

    Science.gov (United States)

    Linetsky, Mikhail; Shipova, Ekaterina; Cheng, Rongzhu; Ortwerth, Beryl J

    2008-01-01

    Previous studies from this laboratory have shown that there are striking similarities between the yellow chromophores, fluorophores and modified amino acids released by proteolytic digestion from calf lens proteins ascorbylated in vitro and their counterparts isolated from aged and cataractous lens proteins. The studies reported in this communication were conducted to further investigate whether ascorbic acid-mediated modification of lens proteins could lead to the formation of lens protein aggregates capable of scattering visible light, similar to the high molecular aggregates found in aged human lenses. Ascorbic acid, but not glucose, fructose, ribose or erythrulose, caused the aggregation of calf lens proteins to proteins ranging from 2.2 x 10(6) up to 3.0 x 10(8 )Da. This compared to proteins ranging from 1.8 x 10(6) up to 3.6 x 10(8 )Da for the water-soluble (WS) proteins isolated from aged human lenses. This aggregation was likely due to the glycation of lens crystallins because [U-(14)C] ascorbate was incorporated into the aggregate fraction and because NaCNBH(3), which reduces the initial Schiff base, prevented any protein aggregation. Reactions of ascorbate with purified crystallin fractions showed little or no aggregation of alpha-crystallin, significant aggregation of beta(H)-crystallin, but rapid precipitation of purified beta(L)- and gamma-crystallin. The aggregation of lens proteins can be prevented by the binding of damaged crystallins to alpha-crystallin due to its chaperone activity. Depending upon the ratios between the components of the incubation mixtures, alpha-crystallin prevented the precipitation of the purified beta(L)- and gamma-crystallin fractions during ascorbylation. The addition of at least 20% of alpha-crystallin by weight into glycation mixtures with beta(L)-, or gamma-crystallins completely inhibited protein precipitation, and increased the amount of the high molecular weight aggregates in solution. Static and dynamic light scattering measurements of the supernatants from the ascorbic acid-modified mixtures of alpha- and beta(L)-, or gamma-crystallins showed similar molar masses (up to 10(8 )Da) and hydrodynamic diameter (up to 80( )nm). These data support the hypothesis, that if the lens reducing environment is compromised, the ascorbylation of lens crystallins can significantly change the short range interactions between different classes of crystallins leading to protein aggregation, light scattering and eventually to senile cataract formation. PMID:18023423

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    Ion Bara

    2006-08-01

    Full Text Available 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 (variantAand germinated seeds in disttilate water, than treated with ascorbic acid in 3 concentrations (variant B.

  14. Amperometric biosensor for ascorbic acid / Biossensor amperométrico para ácido ascórbico

    Scientific Electronic Library Online (English)

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

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

  15. Enhancement by ascorbic acid 2-glucoside or repeated additions of ascorbate of mitogen-induced IgM and IgG productions by human peripheral blood lymphocytes.

    Science.gov (United States)

    Tanaka, M; Muto, N; Gohda, E; Yamamoto, I

    1994-12-01

    In this study, the effect of ascorbic acid 2-glucoside (AA-2G), a stable derivative of ascorbic acid (AsA), or repeated additions of ascorbate on antibody productions by human peripheral blood lymphocytes (PBLs) was examined, and the physiological function of AsA was evaluated. When human PBLs were stimulated with Staphylococcus aureus Cowan I or pokeweed mitogen, AA-2G remarkably increased the numbers of IgM- and IgG-secreting cells which were detected by enzyme-linked immunospot assay. Although a single addition of ascorbate was without effect, the effect of AA-2G was remarkably inhibited by the addition of castanospermine, an alpha-glucosidase inhibitor; and moreover, repeated additions of AsA to the culture medium during the culture period enhanced the response to the same level as did a single addition of AA-2G. These results indicate that AsA has the ability to stimulate the immunoglobulin productions by AA-2G. The phytohemagglutinin-induced proliferative response of PBLs was also stimulated by AA-2G. The intracellular AsA content in PBLs cultured with AA-2G was maintained at relatively high levels during the culture period, whereas the content with a single dose of AsA reached nearly zero by the end of the experiment. These in vitro findings suggest that AA-2G and AsA function as potent immunostimulators of antibody production in humans and that the intracellular AsA content is a key parameter for establishing the immune response of PBLs. PMID:7723222

  16. Protective effect of seminal plasma proteins on the degradation of ascorbic acid.

    Science.gov (United States)

    Liu, L; Dabrowski, K; Ciereszko, A

    1995-07-01

    The objectives of this study were to determine ascorbic acid stability and its effect on antiproteinase activity of seminal plasma in the presence of an oxidant. Effect of seminal plasma, and additives: glutathione, albumin, hydrogen peroxide and Tris buffer, on ascorbic acid degradation was investigated by UV absorbance. Antiproteinase against trypsin amidase activity was measured spectrophotometrically using N-benzoyl-DL-arginine-p-nitroanilide (BAPNA) as substrate. Ascorbic acid was destroyed much more rapidly with the addition of hydrogen peroxide than in Tris buffer at pH 8.2 alone. Seminal plasma protected ascorbic acid more efficiently than glutathione and albumin alone. The protective effect of seminal plasma on ascorbic acid degradation may closely relate to the function of ascorbic acid in reproductive system of scurvy-prone animals including teleost fish. Within the range of 1-8 mM concentrations, ascorbic acid had a pro-oxidant action on seminal plasma antiproteinase activity in vitro when they were incubated with hydrogen peroxide. PMID:7476934

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

    Directory of Open Access Journals (Sweden)

    Ali Akbar Aliabadi

    2006-04-01

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

  18. Dissolution of haematite in citric acid-EDTA-ascorbic acid mixtures

    International Nuclear Information System (INIS)

    This study is related to the development of a suitable mixture of citric acid, EDTA and ascorbic acid (CEA) for dissolving the haematite deposited on the structural surfaces of cooling water circuits in BWRs. The dissolution experiments were performed with synthetically prepared haematite. The dependence of the dissolution rates on each of the constituents of the mixture has been evaluated using a 'grain model'. It was found to be Langmuirian in the case of citric acid, linear in the case of EDTA and independent of ascorbic acid concentration. The ratio of molar concentration of the ligand to the total iron was varied from 0.5-2.5. Activation energy of the dissolution in a CEA mixture having stoichiometrically excess EDTA has been determined by performing experiments upto 353 K. The highest dissolution was obtained in 11:44:4 mol·m-3 and 2:55:4 mol·m-3 CEA mixtures. (author)

  19. 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 = 6.391x +...

  20. 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 ...

  1. Neutralization of local toxicity induced by vipera russelli phospholipase A2 by lipophilic derivative of ascorbic acid.

    Science.gov (United States)

    Mohamed, Riyaz; Shivaprasad, Holenarasipura V; Jameel, Noor M; Shekar, Mysore A; Vishwanath, Bannikuppe S

    2011-01-01

    L-ascorbic acid upon condensation with palmitic acid in the presence of sulphuric acid results in L-ascorbic acid-6-palmitate (AP). The effect of L-ascorbic acid derivative, AP on the pharmacological activities of purified basic multi-toxic PLA2 enzyme, VRV-PL-VIIIa from Vipera russelli snake venom along with in vitro activities is described. AP inhibited VRV-PL-VIIIa enzyme activity in a concentration dependent manner with IC50 value of 48.85 ?M and the inhibition is found to be independent of substrate and calcium concentration. Upon investigating the in vivo pharmacological activities, it has been found that AP inhibited VRV-PL-VIIIa induced mouse paw edematogenic activity in a dose dependant manner. Intramuscular co-injection of AP with VRV-PL-VIIIa (1:10 w:w) neutralized the VRV-PL-VIIIa induced myotoxocity. Sections of mouse thigh muscle showed normal intact musculature with normal levels of serum creatine kinase and lactate dehydrogenase. Histopathological studies showed that administration of VRV-PL-VIIIa (i.p) along with AP mixture inhibited VRV-PL-VIIIa induced lung haemorrhage in mouse indicated that enzyme activity is responsible for all these observed pathological and pharmacological activities. The biophysical interaction studies showed that AP interacted directly with the enzyme and decreased the relative intrinsic fluorescence intensity. CD spectral analysis showed an apparent shift in the far UV-CD spectra of VRV-PL-VIIIa with AP. Docking study also confirmed the interaction of AP with enzyme directly. These results demonstrate that AP neutralizes VRV-PL-VIIIa induced pharmacological activities by inhibiting the enzyme with direct interactions. This compound along with other inhibitors of snake venom hydrolytic enzymes might be of use to neutralize local toxicity of V. russelli venom where antivenoms have failed. PMID:21682683

  2. 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)

  3. 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.

  4. [Examinations of aminoacids in aqueous humour after intravitreous injection of ascorbic acid (author's transl)].

    Science.gov (United States)

    Welge-Lüssen, L; Schimmel, K P

    1978-01-01

    The ascorbic acid concentration of the vitreous of rabbits was experimentally increased to about 20 times the normal value. 24 h after the intravitreal injection of ascorbic acid 13 out of 16 free amino acids were decreased, only Glutamicacid, Glycine and Alanine were increased. 48 h after the injection 13 amino acids were lowered. On the fourth day 8 amino acids were decreased in relation to normal values. After 4 weeks the concentrations of 5 amino acids were raised further compared to the normal values, but 10 amino acids were concentrated lower than the normal values. Also Glu-acid, Gly and Ala had fallen down to the range of the normal values. The total amino acids include the free amino acids and the amino acids, which we find after 6 h hydrolysis. On the first day 11 amino acids showed elevations, 7 amino acids were decreased. After 4 weeks Taurin, Lysine and Histidin were higher than the normal values, 15 amino acids were lower. In single cases the differences were statistically significant. We suppose, that the changes of amino acids are caused by the ascorbic acid or their derivates. There is an anterior drainage after intravitreal injection. We come to the conclusion, that there is a reversible disturbance of the diffusion and active transport of amino acids by ascorbic acid. PMID:692017

  5. 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

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

    Directory of Open Access Journals (Sweden)

    Antonio De Michelis

    2007-01-01

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

  7. 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.

  8. Copper/ascorbic acid dyad as a catalytic system for selective aerobic oxidation of amines.

    Czech Academy of Sciences Publication Activity Database

    Šrogl, Ji?í; Voltrová, Svatava

    2009-01-01

    Ro?. 11, ?. 4 (2009), s. 843-845. ISSN 1523-7060 Institutional research plan: CEZ:AV0Z40550506 Keywords : copper * ascorbic acid * oxidative deamination Subject RIV: CC - Organic Chemistry Impact factor: 5.420, year: 2009

  9. 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.)

  10. Kinetics of degradation of ascorbic acid by cyclic voltammetry method

    Directory of Open Access Journals (Sweden)

    Grudi? Veselinka V.

    2015-01-01

    Full Text Available Cyclic voltammetry was used to examine the kinetics of degradation of ascorbic acid (AA at different temperatures. It has been shown that the reduction of the concentration of AA in all temperatures follow the kinetics of the first order reaction. The rate constant of the oxidation reaction increases with temperature as follows: 5x10-5; 2x10-4; 1x10-3 and 3x10-3 min-1 at temperatures of 25°C, 35°C, 65°C and 90°C, respectively. The temperature dependence of the rate constant follows Arrhenius equation, and the value of activation energy of the reaction degradation is 48.2 kJ mol-1 . The effect of storage time at a temperature of 90 °C on AA content in fresh juice of green peppers was investigated. It was shown that AA oxidation reaction in the juice is also the first order reaction, while the lower rate constant in relation to the pure AA (5x10-3 min-1 indicates the influence of other substances present in peppers.

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

    OpenAIRE

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

    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...

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

    OpenAIRE

    CRAVOTTO, Giancarlo; VINCENTI, Marco; Gobetto, Roberto; Albertino, Andrea; Barge, Alessandro

    2009-01-01

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

  13. Formulation with ascorbic acid and sucrose modulates catechin bioavailability from green tea

    OpenAIRE

    Peters, Catrina M.; Green, Rodney J.; Janle, Elsa M; Ferruzzi, Mario G.

    2010-01-01

    In order to investigate the impact of common food ingredients on catechin absorption, green tea (GT) extract (50 mg) was formulated plain, with sucrose (GT+S), with ascorbic acid (GT+AA) and with sucrose and ascorbic acid (GT+S+AA). Bioavailability and bioaccessibility were assessed in Sprague Dawley rats and an in vitro digestion/Caco-2 cell model respectively. Absorption of epigallocatechin (EGC) and epigallocatechin gallate (EGCG) was significantly (P

  14. Flow injection-chemiluminescence determination of ascorbic acid based on luminol–ferricyanide–gold nanoparticles system

    International Nuclear Information System (INIS)

    A novel flow-injection chemiluminescence (CL) method for the determination of ascorbic acid (AA) is proposed, based upon its enhancing effect on the CL reaction of luminol with ferricyanide catalyzed by gold nanoparticles in alkaline solution. Different sizes gold nanoparticles exhibited different catalyzing effect towards luminol CL and 38 nm gold nanoparticles exhibited the best enhancing effect. Under the optimal experimental conditions, a linear relationship was obtained between the CL intensity and the concentration of ascorbic acid in the range of 1.0×10?10–1.0×10?6 mol L?1. The detection limit was 2.0×10–11 mol ?1 and the relative standard deviation for 1.0×10?6 mol L?1 ascorbic acid was 0.71% (n=10). This method has been successfully applied in the determination of ascorbic acid in several real samples. - Highlights: • Gold nanoparticles could enhance luminol–K3Fe(CN)6 CL signal. • 38 nm gold nanoparticles exhibited the best catalyzing effect. • Ascorbic acid could further enhance luminol–K3Fe(CN)6–gold nanoparticles CL. • Ascorbic acid could be detected sensitively based on its enhancing effect

  15. 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

  16. 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.

  17. 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.

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

    OpenAIRE

    Gamze Erdo?du; Mehmet Mutluhan Mutlu

    2011-01-01

    Poly (m-aminobenzene sulfonic acid, m-ABSA) films were electrochemically prepared by cyclic voltammetry (CV) in 0.1 mol L–1 KCl solution. The dopamine (DA) selectivity of polymeric electrodes prepared at the different thicknesses was examined in the presence of ascorbic acid (AA). The results showed that the modified electrode showed an excellent electrocatalytical effect towards oxidation of dopamine (DA) and ascorbic acid (AA). Electrostatic interaction between the negatively charged poly(m...

  19. The effects of dietary ascorbic acid supplementation on collagen and amino acid concentrations in Japanese quails exposed to heat stress

    OpenAIRE

    SEYREK, Kamil; ERBA?, Hakan; Serter, Mukadder; YEN?SEY, Çi?dem

    2010-01-01

    A considerable body of data exists regarding the role of vitamin C in mammalian physiology; however, there are no data about the effects of dietary ascorbic acid supplementation on collagen concentrations and amino acid levels in animals exposed to heat stress. The present study investigated the effects of supplementary ascorbic acid intake on collagen concentrations in the brain and heart tissue in Japanese quails. In addition, glycine, glutamine, histidine, asparagine, and serine contents i...

  20. The effects of ?-tocopherol and ascorbic acid glucosides on radiation- and H2O2-induced decomposition of thymine in aqueous solution

    International Nuclear Information System (INIS)

    The effects of ascorbic acid, ascorbic acid glycoside and ?-tocopherol monoglycoside on radiation- and H2O2-induced decomposition of thymine in aqueous solutions were investigated. Of the three compounds studied, ascorbic acid glycoside was found to possess the most marked protecting properties. An explanation of this phenomenon has been given in terms of differences in molecular structures of ascorbic acid and ascorbic acid glycoside, as well as properties of radical adducts formed during their interaction with OH radicals. (authors)

  1. 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)

  2. 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...

  3. 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...

  4. 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.

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

    International Nuclear Information System (INIS)

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

  6. Relief of delayed oxidative stress by ascorbic acid can suppress radiation-induced cellular senescence in mammalian fibroblast cells.

    Science.gov (United States)

    Kobashigawa, Shinko; Kashino, Genro; Mori, Hiromu; Watanabe, Masami

    2015-03-01

    Ionizing radiation-induced cellular senescence is thought to be caused by nuclear DNA damage that cannot be repaired. However, here we found that radiation induces delayed increase of intracellular oxidative stress after irradiation. We investigated whether the relief of delayed oxidative stress by ascorbic acid would suppress the radiation-induced cellular senescence in Syrian golden hamster embryo (SHE) cells. We observed that the level of oxidative stress was drastically increased soon after irradiation, then declined to the level in non-irradiated cells, and increased again with a peak on day 3 after irradiation. We found that the inductions of cellular senescence after X-irradiation were reduced along with suppression of the delayed induction of oxidative stress by treatment with ascorbic acid, but not when oxidative stress occurred immediately after irradiation. Moreover, treatment of ascorbic acid inhibited p53 accumulation at 3 days after irradiation. Our data suggested a delayed increase of intracellular oxidative stress levels plays an important role in the process of radiation-induced cellular senescence by p53 accumulation. PMID:25958121

  7. Construction of an optical sensor for the determination of ascorbic acid using ionic liquids as modifier.

    Science.gov (United States)

    Absalan, Ghodratollah; Arabi, Maryam; Tashkhourian, Javad

    2012-01-01

    An optode was designed for an indirect determination of ascorbic acid by using neocuproine, which has been coated on transparent triacetylcellulose film as a membrane. The proposed method is based on the oxidation of ascorbic acid to dehydroascorbic acid with the Cu(II) and neocuproine reagent. The increase in the absorbance value of the optode at the maximum wavelength of 455 nm was related to the ascorbic acid concentration in aqueous samples. The sensitivity of the method was improved by using room-temperature ionic liquid, [C(8)MIM][PF(6)]. The linear dynamic range for the determination of ascorbic acid was 7.4 × 10(-5) - 3.5 × 10(-3) mol L(-1) with a limit of detection of 2.2 × 10(-5) mol L(-1) (n = 10) and a response time range of 6.0 - 8.0 min. The optode was successfully applied for the determination of ascorbic acid in orange juice. PMID:23232246

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

    International Nuclear Information System (INIS)

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

  9. 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.

  10. Effects of low-dose irradiation on the free amino acid, glucose and ascorbic acid contents of potato

    International Nuclear Information System (INIS)

    Free amino acid, glucose and ascorbic acid contents of potato with doses of 0.05, 0.1 and 0.15 kGy have been investigated immediately after irradiation. Aspartic acid and glutamic acid decreased about 50 % at a dose of 0.15 kGy. An increase in the glucose content has been observed with increase in radiation doses. A decrease of approximately 20, 36 and 43 % in ascorbic acid was observed in 0.05, 0.10 and 0.15 kGy irradiated potatoes than that of the unirradiated one. (author)

  11. Ascorbic acid protects lipids in human plasma and low-density lipoprotein against oxidative damage

    Energy Technology Data Exchange (ETDEWEB)

    Frei, B. (Department of Nutrition, Harvard School of Public Health, Boston, MA (Unites States))

    1991-12-01

    The authors exposed human blood plasma and low-density lipoprotein (LDL) to many different oxidative challenges and followed the temporal consumption of endogenous antioxidants in relation to the initiation of oxidative damage. Under all types of oxidizing conditions, ascorbic acid completely protects lipids in plasma and LDL against detectable peroxidative damage as assessed by a specific and highly sensitive assay for lipid peroxidation. Ascorbic acid proved to be superior to the other water-soluble plasma antioxidants bilirubin, uric acid, and protein thiols as well as to the lipoprotein-associated antioxidants alpha-tocopherol, ubiquinol-10, lycopene, and beta-carotene. Although these antioxidants can lower the rate of detectable lipid peroxidation, they are not able to prevent its initiation. Only ascorbic acid is reactive enough to effectively intercept oxidants in the aqueous phase before they can attack and cause detectable oxidative damage to lipids.

  12. The Effect of Ascorbic Acid on Mancozeb-Induced Toxicity in Rat Thymocytes.

    Science.gov (United States)

    Pavlovic, V; Cekic, S; Kamenov, B; Ciric, M; Krtinic, D

    2015-01-01

    Mancozeb, as a dithiocarbamate fungicide, has been found to exhibit toxicological manifestations in different cells, mainly by generation of free radicals which may alter antioxidant defence systems in cells. The effect of mancozeb on the cells of a primary lymphoid organ has not been studied. In the present study, the effects of mancozeb (0.2, 2 and 5 ?g/ml) or mancozeb+ascorbic acid (100 ?g/ml), or ascorbic acid alone or control medium alone on the levels of cell viability, apoptosis, intracellular reactive oxygen species production (ROS), mitochondrial membrane potential (MMP) and ATP levels in rat thymocytes were examined in vitro. Cells treated with mancozeb displayed a concentration-dependent increase of hypodiploid cells and ROS production followed by markedly decreased viability of the cells, MMP and ATP levels. Application of ascorbic acid significantly reduced cytotoxicity in cell cultures treated with 0.2 and 2 ?g/ml of mancozeb, together with significantly decreased ROS levels and increased MMP and ATP levels. In cells treated with 5 ?g/ml of mancozeb, ascorbic acid failed to reduce toxicity while simultaneously increasing the apoptosis rate of thymocytes. These results suggest that ROS plays a significant role in mancozeb-induced toxicity, through alteration of mitochondrial function. Ascorbic acid administration reduced the toxicity rate in cells treated with lower mancozeb concentrations, while it may have the ability to shift cells from necrosis to apoptosis in the presence of highest mancozeb concentrations. PMID:26213857

  13. 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)

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

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Timm Heinrich, Maike

    2001-01-01

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

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

    Science.gov (United States)

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

    2013-12-01

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

  16. 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 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.

  17. 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.

  18. 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.

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

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

    OpenAIRE

    Abbasi; M. Niakousari

    2008-01-01

    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...

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

    Directory of Open Access Journals (Sweden)

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

    2004-07-01

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

  1. Electrochemical impedance based chiral analysis of anti-ascorbutic drug: l-Ascorbic acid and d-ascorbic acid using C-dots decorated conductive polymer nano-composite electrode.

    Science.gov (United States)

    Pandey, Indu; Kant, Rama

    2016-03-15

    Clinical manifestations owing to l-ascorbic acid for scurvy as comparison to d-ascorbic acid and challenges of chiral purity are overcome by using chiral selective conductive polymer nanocomposite which mimics antibodies and enzymes. A novel chiral selective imprinted polyaniline-ferrocene-sulfonic acid film has been electrochemically fabricated on C-dots modified pencil graphite electrode. The performance of the obtained l-ascorbic acid or d-ascorbic acid chiral selective sensor was investigated by electrochemical impedance spectroscopy, cyclic and differential pulse voltammetry. The surface characteristics of the C-dots, chiral sensor before and after the de-doping of chiral d- and l-ascorbic acid were characterized by scanning electron microscopy, Raman spectroscopy and X-ray diffraction spectroscopy. Excellent recognition results were obtained by difference in electron transfer resistance. The proposed chiral sensor is capable of measuring d-ascorbic acid or l-ascorbic acid in aqueous as well as in real and commercial samples within the range of 0.020-0.187nM and 0.003-0.232nM with detection limit of 0.00073nM and 0.00016nM, respectively. The proposed method has also been examined for the chiral selective recognition of ascorbic acid isomers (d- and l-) quantitatively, in complicated matrices of real samples. PMID:26499067

  2. Ascorbic acid glycation of lens proteins produces UVA sensitizers similar to those in human lens

    Energy Technology Data Exchange (ETDEWEB)

    Ortwerth, B.J.; Linetsky, Mikhail; Olesen, P.R. [Missouri Univ., Columbia, MO (United States). Mason Inst. of Ophthalmology

    1995-09-01

    Soluble calf lens proteins were extensively glycated during a 4 week incubation with ascorbic acid in the presence of oxygen. Amino acids analysis of the dialyzed proteins removed at weekly intervals showed an increasing loss of lysine, arginine and histidine, consistent with the extensive protein cross-linking observed. Irradiation of the dialyzed samples with UVA light (1.0 kJ/cm{sup 2} total illumination through a 338 nm cutoff filter) caused an increasing loss of tryptophan, an additional loss of histidine and the production of micromolar concentrations of hydrogen peroxide. No alteration in amino acid content and no photolytic effects were seen in proteins incubated without ascorbic acid in proteins incubated with glucose for 4 weeks. The rate of hydrogen peroxide formation was linear with each glycated sample with a maximum production of 25 nmol/mg protein illuminated. The possibility that the sensitizer activity was due to an ascorbate-induced oxidation of tryptophan was eliminated by the presence of a heavy metal ion chelator during the incubation and by showing equivalent effects with ascorbate-incubated ribonuclease A, which is devoid of tryptophan. The ascorbate-incubated samples displayed increasing absorbance at wavelengths above 300 nm and increasing fluorescence (340/430) as glycation proceeded. The spectra of the 4 week glycated proteins were identical to those obtained with a solubilized water-insoluble fraction from human lens, which is known to have UVA sensitizer activity. (Author).

  3. 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.

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

    OpenAIRE

    Anwar, Bilal; Khan, Shakil Akhtar; Aslam, Asim; MAQBOOL, Azhar; Khan, Kashif Aziz

    2004-01-01

    A total of 100, day-old broiler chicks were randomly divided into 5 equal groups and kept under elevated temperature (93-97°F) to see the effect of ascorbic acid and acetylsalicylic acid on the feed conversion ratio (FCR), immune status and ratio of weight of bursa, thymus and spleen to body weight. Heat stress increased the FCR but decreased the immune response and ratio of bursa, thymus and spleen to body weight of the birds. Ascorbic acid and acetylsalicylic acid supplementation during hea...

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

    OpenAIRE

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

    2004-01-01

    A total of 100, day-old broiler chicks were randomly divided into 5 equal groups and kept under elevated temperature (93-97oF) to see the effect of ascorbic acid and acetylsalicylic acid on the feed conversion ratio (FCR), immune status and ratio of weight of bursa, thymus and spleen to body weight. Heat stress increased the FCR but decreased the immune response and ratio of bursa, thymus and spleen to body weight of the birds. Ascorbic acid and acetylsalicylic acid supplementation during hea...

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

    Directory of Open Access Journals (Sweden)

    M. Shahedi

    2001-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Sunday Abraham Musa

    2012-12-01

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

  8. Signal transduction pathway for L-ascorbic acid- and L-ascorbic acid 2-glucoside-induced DNA synthesis and cell proliferation in primary cultures of adult rat hepatocytes.

    Science.gov (United States)

    Moteki, Hajime; Shimamura, Yuya; Kimura, Mitsutoshi; Ogihara, Masahiko

    2012-05-15

    We examined the effects of L-ascorbic acid and its analogues on DNA synthesis and cell proliferation. We also investigated the signal transduction pathways involved in the induction of mitogenesis by L-ascorbic acid and its analogues using primary cultures of adult rat hepatocytes. Following a 4-h serum-free cultivation, both L-ascorbic acid and its stable analogue, L-ascorbic acid 2-glucoside, time- and dose-dependently stimulated hepatocyte DNA synthesis and cell proliferation, with EC?? values of 6.46×10?? M and 3.34×10?? M, respectively. Dehydroascorbic acid (10?? M-10?? M) weakly stimulated hepatocyte mitogenesis, whereas isoascorbic acid (10?? M-10?? M) had no effect. Hepatocyte mitogenesis induced by L-ascorbic acid or L-ascorbic acid 2-glucoside was dose-dependently abolished by treatment with monoclonal antibodies against insulin-like growth factor (IGF)-I receptor, but not by treatment with monoclonal antibodies against insulin receptor or IGF-II receptor. Western blot analysis showed that both L-ascorbic acid and L-ascorbic acid 2-glucoside significantly stimulated IFG-I receptor tyrosine kinase activity within 3 min, and mitogen-activated protein (MAP) kinase activity within 5 min. These results demonstrate that both L-ascorbic acid and L-ascorbic acid 2-glucoside induce DNA synthesis and cell proliferation in primary cultures of adult rat hepatocytes by interacting with the IGF-I receptor site and by activating the receptor tyrosine kinase/MAP kinase pathway. PMID:22429571

  9. Modulating Effect of Ascorbic Acid on Transport-Induced Immunosuppression in Goats

    OpenAIRE

    Ndazo Salka Minka; Joseph Olusegun Ayo

    2011-01-01

    The effect of 12?h road transportation on some basic blood cells and the modulating role of ascorbic acid were investigated in 40 adult Red Sokoto goats during the hot dry season. The animals were divided into two groups, GI (experimental; n = 20) and GII (control; n = 20). Group 1 was administered with ascorbic acid (AA) per os at a dosage rate of 100?mg/kg body weight, while GII was given 10?mL of sterile water per goat. Forty minutes after the administration and loading, the goats were tra...

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

    OpenAIRE

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

    2014-01-01

    In this work, the influence of the electric field frequency and solids content on the degradation kinetics of ascorbic acid during ohmic heating of acerola pulp and acerola serum was investigated. The degradation percentage of ascorbic acid in the pulp after 120 min of heating varied between 12 and 17%. For the serum, the degradation percentage was in the range of 13 and 18%. The results were fitted to the first-order model, and the kinetic rate constants ranged from 1.1 to 1.6 × 10?3 min?1 a...

  11. 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 ...

  12. 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.

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

    OpenAIRE

    Shamoon Naseem; M. Younus; Bilal Anwar; Aamir Ghafoor; Asim Aslam; Akhter, S

    2005-01-01

    A total of 100, day-old broiler chickens were randomly divided into 5 groups and kept under elevated temperature (34-36oC) to see the effect of ascorbic acid and acetylsalicylic acid (Sb-Asper-C, a commercial product) on the feed conversion ratio (FCR), immune status and ratio of weight of bursa, thymus and spleen to body weight. Heat stress increased the FCR but decreased the immune response and ratio of bursa, thymus and spleen to body weight of the birds. Ascorbic acid and acetylsal...

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Mohamed, H. E.

    2006-01-01

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

  16. Ascorbic Acid Profiles in 'Delicious' and 'Honeycrisp' Apples During on-Tree Development and Cold Storage

    Science.gov (United States)

    Reactive oxygen species (ROS) produced in plants are involved in a number of processes both beneficial (signal transduction) and detrimental (induction of physiological disorders). ROS toxicity can be ameliorated by a number of metabolic systems or compounds in plant tissue including L-Ascorbic acid...

  17. INFLUENCES OF THIAMINE AND/OR ASCORBIC ACID ON LEAD INTOXICATION

    Directory of Open Access Journals (Sweden)

    M. Ghazi-Khansari

    1996-07-01

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

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    Samina Malik and Muhammad Ashraf

    2012-05-01

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

  20. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-05-01

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

  2. 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.

  3. Decolorization of structurally different synthetic dyes using cobalt(II)/ascorbic acid/hydrogen peroxide system.

    Czech Academy of Sciences Publication Activity Database

    Verma, P.; Baldrian, Petr; Nerud, František

    2002-01-01

    Ro?. 50, - (2002), s. 975-979. ISSN 0045-6535 R&D Projects: GA ?R GA526/01/0915 Institutional research plan: CEZ:AV0Z5020903 Keywords : dye decolorization * cobalt * ascorbic acid Subject RIV: EE - Microbiology, Virology Impact factor: 1.461, year: 2002

  4. Decolorization ofstricturally different synthetic dyes using cobalt(II)/ascorbic acid/hydrogen peroxide system.

    Czech Academy of Sciences Publication Activity Database

    Verma, P.; Baldrian, Petr; Nerud, František

    2003-01-01

    Ro?. 50, - (2003), s. 975-979. ISSN 0045-6535 R&D Projects: GA ?R GA526/01/0915 Institutional research plan: CEZ:AV0Z5020903 Keywords : dye decolorization * cobalt * ascorbic acid Subject RIV: EE - Microbiology, Virology Impact factor: 1.904, year: 2003

  5. 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.)

  6. 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 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

  7. 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.

  8. Characterization of a new malignant human T-cell line (PFI-285) sensitive to ascorbic acid.

    Science.gov (United States)

    Helgestad, J; Pettersen, R; Storm-Mathisen, I; Schjerven, L; Ulrich, K; Smeland, E B; Egeland, T; Sørskaard, D; Brøgger, A; Hovig, T

    1990-01-01

    A new malignant human T-cell line-labelled PFI-285-has been isolated from a boy with malignant lymphoma. Morphologically, the cells had characteristics of malignant lymphoid cells. The cells presented surface antigens as early cortical lymphocytes and proliferated non-adherently as single cells, independent of T-cell growth factor (IL-2), in liquid culture. The cells had undetectable levels of receptors for IL-2, were not clonogenic in soft agar, but did form tumors in nude mice. Their establishment and continuous growth in vitro was dependent on the number of cells inoculated and on the growth medium used. Cytogenetic alteration, HTLV-1 or reverse transcriptase activity were not detected. The production of known T-cell derived lymphokines such as IL-2, B-cell growth factor(s), alpha-interferon or granulocyte/macrophage colony stimulating or inhibiting factor(s) was not detected. The cells had 5-8% natural killer (NK)-cell activity against NK-cell sensitive target cells (K562) and were not sensitive for NK cells. A most unusual characteristic was the pronounced sensitivity of the cells to ascorbic acid. Concentrations down to 50 mumol/l killed the cells within hours. PMID:2307225

  9. 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 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

  10. Ascorbic acid supplementation diminishes microparticle elevations and neutrophil activation following SCUBA diving.

    Science.gov (United States)

    Yang, Ming; Barak, Otto F; Dujic, Zeljko; Madden, Dennis; Bhopale, Veena M; Bhullar, Jasjeet; Thom, Stephen R

    2015-08-15

    Predicated on evidence that diving-related microparticle generation is an oxidative stress response, this study investigated the role that oxygen plays in augmenting production of annexin V-positive microparticles associated with open-water SCUBA diving and whether elevations can be abrogated by ascorbic acid. Following a cross-over study design, 14 male subjects ingested placebo and 2-3 wk later ascorbic acid (2 g) daily for 6 days prior to performing either a 47-min dive to 18 m of sea water while breathing air (?222 kPa N2/59 kPa O2) or breathing a mixture of 60% O2/balance N2 from a tight-fitting face mask at atmospheric pressure for 47 min (?40 kPa N2/59 kPa O2). Within 30 min after the 18-m dive in the placebo group, neutrophil activation, and platelet-neutrophil interactions occurred, and the total number of microparticles, as well as subgroups bearing CD66b, CD41, CD31, CD142 proteins or nitrotyrosine, increased approximately twofold. No significant elevations occurred among divers after ingesting ascorbic acid, nor were elevations identified in either group after breathing 60% O2. Ascorbic acid had no significant effect on post-dive intravascular bubble production quantified by transthoracic echocardiography. We conclude that high-pressure nitrogen plays a key role in neutrophil and microparticle-associated changes with diving and that responses can be abrogated by dietary ascorbic acid supplementation. PMID:26084697

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

    International Nuclear Information System (INIS)

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

  12. Betalain, Acid Ascorbic, Phenolic Contents and Antioxidant Properties of Purple, Red, Yellow and White Cactus Pears

    OpenAIRE

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

    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, betac...

  13. Glycation by ascorbic acid oxidation products leads to the aggregation of lens proteins

    OpenAIRE

    Linetsky, Mikhail; Shipova, Ekaterina; CHENG, RONGZHU; Ortwerth, Beryl J.

    2008-01-01

    Previous studies from this laboratory have shown that there are striking similarities between the yellow chromophores, fluorophores and modified amino acids released by proteolytic digestion from calf lens proteins ascorbylated in vitro and their counterparts isolated from aged and cataractous lens proteins. The studies reported in this communication were conducted to further investigate whether ascorbic acid-mediated modification of lens proteins could lead to the formation of lens protein a...

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

    Directory of Open Access Journals (Sweden)

    Yukihiro Takahashi

    2013-09-01

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

  15. 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.

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

    OpenAIRE

    H.E. Mohamed

    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...

  17. Effects of Ascorbic Acid on the Performance and Some Blood Parameters of Japanese Quails Reared Under Hot Climate Conditions

    OpenAIRE

    AVCI, Mehmet

    2005-01-01

    The effects of ascorbic acid on the performance and some blood parameters of Japanese quails reared under hot conditions were investigated. Three hundred Japanese quails, 7 days of age, were randomly divided into one control and two experimental groups, comprising five replicates of 20 birds each. Ascorbic acid (500 and 1000 mg/kg) was given to the experimental groups. The body weight gain increased significantly (P < 0.05) in the group given 500 mg/kg of ascorbic acid until the fourth wee...

  18. 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; Farver, O; Thorn, N A

    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 o...

  19. The application of conducting polymer nanoparticle electrodes to the sensing of ascorbic acid.

    Science.gov (United States)

    Ambrosi, Adriano; Morrin, Aoife; Smyth, Malcolm R; Killard, Anthony J

    2008-02-18

    An ascorbic acid sensor was fabricated via the drop-casting of dodecylbenzene sulphonic acid (DBSA)-doped polyaniline nanoparticles onto a screen-printed carbon-paste electrode. The modified electrode was characterised with respect to the numbers of drop cast layers, optimum potential and operating pH. The sensor was found to be optimal at neutral pH and at 0V vs. Ag/AgCl. Under these conditions, the sensor showed good selectivity and sensitivity in that it did not respond to a range of common interferents such as dopamine, acetaminophen, uric acid and citric acid, but was capable of the detection of ascorbic acid at a sensitivity of 0.76 microA mM(-1) or 10.75 microA mM(-1) cm(-2) across a range from 0.5 to 8mM (r2=0.996, n=6), and a limit of detection of 8.3 microM (S/N=3). The sensor was compared to a range of other conducting polymer-based ascorbate sensors and found to be comparable or superior in terms of analytical performance. PMID:18243871

  20. 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?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.

  1. 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

  2. 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)

  3. 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

  4. Structure, spectra and antioxidant action of ascorbic acid studied by density functional theory, Raman spectroscopic and nuclear magnetic resonance techniques.

    Science.gov (United States)

    Singh, Gurpreet; Mohanty, B P; Saini, G S S

    2016-02-15

    Structure, vibrational and nuclear magnetic resonance spectra, and antioxidant action of ascorbic acid towards hydroxyl radicals have been studied computationally and in vitro by ultraviolet-visible, nuclear magnetic resonance and vibrational spectroscopic techniques. Time dependant density functional theory calculations have been employed to specify various electronic transitions in ultraviolet-visible spectra. Observed chemical shifts and vibrational bands in nuclear magnetic resonance and vibrational spectra, respectively have been assigned with the help of calculations. Changes in the structure of ascorbic acid in aqueous phase have been examined computationally and experimentally by recording Raman spectra in aqueous medium. Theoretical calculations of the interaction between ascorbic acid molecule and hydroxyl radical predicted the formation of dehydroascorbic acid as first product, which has been confirmed by comparing its simulated spectra with the corresponding spectra of ascorbic acid in presence of hydrogen peroxide. PMID:26580511

  5. 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.

  6. Solubilities of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid in water

    International Nuclear Information System (INIS)

    The solubility in water of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid was determined in the 278.15 K to 343.15 K temperature range. The solubility of these compounds served to permit the evaluation of the apparent molar enthalpies of solution

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

    International Nuclear Information System (INIS)

    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. - Highlights: • 2.0% ascorbic acid and 1.0 kGy inhibited PPO activity in minimally processed eggplant. • Above treatment maintained creamy white color and storage quality up to 6 days at 3±1 °C. • The treatment gave 1.5 log reductions in microbial counts, thus enhancing microbial safety. • The treatment can provide convenience to consumer and will reduce spoilage during storage

  8. Modulating effect of ascorbic Acid on transport-induced immunosuppression in goats.

    Science.gov (United States)

    Minka, Ndazo Salka; Ayo, Joseph Olusegun

    2011-01-01

    The effect of 12?h road transportation on some basic blood cells and the modulating role of ascorbic acid were investigated in 40 adult Red Sokoto goats during the hot dry season. The animals were divided into two groups, GI (experimental; n = 20) and GII (control; n = 20). Group 1 was administered with ascorbic acid (AA) per os at a dosage rate of 100?mg/kg body weight, while GII was given 10?mL of sterile water per goat. Forty minutes after the administration and loading, the goats were transported for 12?h. The result obtained in GII goats showed that loading, transportation, high ambient temperature (AT), and relative humidity (RH) encountered during transportation induced lymphopenia, neutrophilia, and eosinopenia, which can cause immunosuppression. In GI goats, the administration of AA prior to loading and transportation ameliorated the adverse effects of loading and transportation stress on neutrophil/lymphocyte ratio and eosinopenia of the goats. PMID:23738106

  9. 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

  10. The crystal structure and physicochemical properties of L-ascorbic acid 2-glucoside.

    Science.gov (United States)

    Mandai, T; Yoneyama, M; Sakai, S; Muto, N; Yamamoto, I

    1992-08-01

    The stable L-ascorbic acid glucoside produced by the action of the cyclomaltodextrin glucanotransferase (CGTase, EC 2.4.1.19) from Bacillus stearothermophilus was crystallized from an aqueous solution. Determination of the molecular structure by single crystal X-ray analysis showed the compound to be 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G). The crystals are orthorhombic, space group P2(1)2(1)2(1), with unit-cell dimensions a = 11.929 A, b = 24.351 A, and c = 4.864 A. The D-glucopyranose residue has the 4C1 conformation. These conclusions are in good agreement with those based on the 13C-NMR spectrum. The general physicochemical properties of crystalline AA-2G are reported. PMID:1423355

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

    Science.gov (United States)

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

    2013-03-15

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

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

    Science.gov (United States)

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

    2013-12-01

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Supranee MANURAKCHINAKORN

    2004-06-01

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

  15. 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.

  16. 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.

    2013-12-01

    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.

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

    Scientific Electronic Library Online (English)

    Martín Roberto, Alvarez; Fernando Osvaldo, Kravetz.

    2009-06-01

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

  18. Elimination of ascorbic acid after high-dose infusion in prostate cancer patients

    DEFF Research Database (Denmark)

    Nielsen, Torben Kjær; Højgaard, Martin; Andersen, Jon Thor Trærup; Poulsen, Henrik Enghusen; Lykkesfeldt, Jens; Mikines, Kari Joensen

    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 metast...

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

    OpenAIRE

    Drew N. Buchanan; Omaye, Stanley T.

    2013-01-01

    Hydroponically-grown produce may be a way of helping to feed the world a variety of fruits and vegetables, regardless of soil quality, space availability or climate. The objective of this study was to determine whether hydroponicallygrown lettuce contains as much ascorbic acid and tocopherol as soil-grown lettuce. We analyzed four varieties of lettuce, including: Waldmann’s Dark Green, Red Lollo Antago, Red Romaine Annapolis, and Butterleaf. The tocopherol content of hydroponically-grown Wald...

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

    OpenAIRE

    A.I. Okwori; P.C. Njoku; C.D. Tuleun

    2010-01-01

    A 2 x 2 factorial experiment was conducted to determine the performance of 400 Anak broiler chicks exposed to two lighting regimes viz. 12 h light:12 h darkness and 24 h light:0 h darkness and fed diets containing two levels of ascorbic acid (0 and 250 mg AA/kg of feed). Each treatment was replicated four times with 25 birds per replicate. Results showed that at the starter phase of growth, chicks on continuous lighting regime recorded significantly (p

  1. 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...

  2. Effects of ascorbic acid on UV light-mediated photoreceptor damage in isolated rat retina

    OpenAIRE

    Tokuda, Kazuhiro; Zorumski, Charles F.; Izumi, Yukitoshi

    2007-01-01

    Concerns have been raised about whether operating microscopes and endoillumination used during ophthalmic surgeries contribute to retinal damage. Despite the recognition that ascorbic acid (vitamin C) helps to protect the eye from light and the abundance of vitamin C in the retina, artificial aqueous humors used during surgery only contain the antioxidant glutathione. To test whether inclusion of antioxidants other than glutathione in surgical solutions might help to preserve retinal integrit...

  3. Antioxidant capacity and contents of phenols, ascorbic acid, ?-carotene and lycopene in lettuce

    OpenAIRE

    Zdravkovi? Jasmina M.; A?amovi?-?okovi? Gordana S.; Mladenovi? Jelena D.; Pavlovi? Radoš M.; Zdravkovi? Milan S.

    2014-01-01

    The antioxidant activity of three lettuce varieties (Lactuca sativa L.) Emerald, Vera and Neva, cultivated in two kinds of protected spaces, a glasshouse and a plastic greenhouse, under controlled conditions, was determined. The content of antioxidant compounds: total phenols, flavonoids, L-ascorbic acid, ß-carotene and lycopene, were determined in ethanolic extracts of the lettuce with spectrophotometric methods. The largest content of total phenols (78.98...

  4. Killing of Bacillus Spores by Aqueous Dissolved Oxygen, Ascorbic Acid, and Copper Ions

    OpenAIRE

    Cross, J. B.; Currier, R. P.; Torraco, D. J.; Vanderberg, L. A.; Wagner, G. L.; Gladen, P. D.

    2003-01-01

    An approach to decontamination of biological endospores is discussed. Specifically, the performance of an aqueous modified Fenton reagent is examined. A modified Fenton reagent formulation of cupric chloride, ascorbic acid, and sodium chloride is shown to be an effective sporicide under aerobic conditions. The traditional Fenton reaction involves the conversion of hydrogen peroxide to hydroxyl radical by aqueous ionic catalysts such as the transition metal ions. Our modified Fenton reaction i...

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

    OpenAIRE

    Samina Malik and Muhammad Ashraf

    2012-01-01

    Drought causes considerable reduction in plant growth. A hydroponic experiment was conducted to appraise the potential role of exogenously applied ascorbic acid in alleviating the effect of drought on wheat. Two contrasting wheat genotypes, a drought tolerant cultivar Chakwal-86 and a drought sensitive strain 6544-6 were used in the study. Drought was induced by dissolving 20% Polyethylene glycol (PEG8000) in the nutrient solution producing -0.6MPa osmotic stress. Drought caused a significant...

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

    OpenAIRE

    Maria+Magdalena Zamfirache; Zenovia Olteanu; Stefania Surdu; Elena Truta

    2006-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Maria+Magdalena Zamfirache

    2006-08-01

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

  8. 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.

  9. 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

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

    Science.gov (United States)

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

    2014-06-25

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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  13. 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)

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

    International Nuclear Information System (INIS)

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

  15. Effect of ascorbic acid and particle size on iron absorption from ferric pyrophosphate in adult women.

    Science.gov (United States)

    Fidler, Meredith C; Davidsson, Lena; Zeder, Christophe; Walczyk, Thomas; Marti, Irene; Hurrell, Richard F

    2004-07-01

    The effects of added ascorbic acid and particle size on iron absorption from ferric pyrophosphate were evaluated in adult women (9-10 women/study) based on erythrocyte incorporation of iron stable isotopes (57Fe or 58Fe) 14 days after administration. Three separate studies were made with test meals of iron-fortified infant cereal (5 mg iron/meal) and the results are presented as geometric means and relative bioavailability values (RBV, FeSO4 = 100%). The results of study 1 showed that iron absorption was significantly lower from ferric pyrophosphate (mean particle size 8.5 microm) than from FeSO4 in meals without ascorbic acid (0.9 vs. 2.6%, p ferric pyrophosphate slightly less (2.6-fold) than from FeSO4 (3.7-fold) (p ferric pyrophosphate with an average particle size of 6.7 microm and 12.5 pm was not significantly different at 52 and 42% (p > 0.05), respectively. In conclusion, the addition of ascorbic acid increased fractional iron absorption from ferric pyrophosphate significantly, but to a lesser extent than from FeSO4. Decreasing the mean particle size to 6.7 microm did not significantly increase iron absorption from ferric pyrophosphate. PMID:15580812

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

    Directory of Open Access Journals (Sweden)

    Vardhan Vishnu A

    2005-03-01

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

  17. Ascorbic acid enhances adipogenesis of 3T3-L1 murine preadipocyte through differential expression of collagens

    Science.gov (United States)

    2013-01-01

    Background Adipogenesis from preadipocytes into mature adipocyte is precisely coordinated by transcription factors such as CCAAT-enhancer-binding proteins (C/EBPs) and peroxisome proliferator-activated receptor ? (PPAR?), cytokines, and hormones, which is accompanied by extracellular matrix remodeling. Besides anti-oxidant activity, ascorbic acid (ASC) is participating in collagen biosynthesis and increase production and processing of collagens. Moreover, several studies demonstrated that ASC enhanced differentiation from preadipocytes into mature adipocytes. Methods The adipogenic effect of ascorbic acid was evaluated in chemical induced 3T3-L1 by Oil Red O staining. This effect was elucidated by immunoblotting which detected the expression level of collagens and transcription factors in adipogenesis. The immunocytochemical determination of type I collagen was performed in 3T3-L1 adipocyte to show the change of extracellular matrix during adipogenesis. Results In this study, Oil Red O staining in 3T3-L1 preadipocytes was increased dose-dependently by addition of ASC. These ASC-treated adipocytes increased collagen processing of ?1(I) and ?1(V) and expressed ?1(VI) and ?2(VI) collagens differentially. ASC also stimulated expression of C/EBP? and PPAR?, which is preceded by collagen enhancement. In addition, inhibition of ASC activity by ethyl-3,4-dihydroxybenzoate showed reduction of lipid accumulation by removal of large lipid droplets, not by inhibition of lipid production. This observation went with loss of ?1(I) deposition on adipocyte surface, increase of ?1(V) and ?2(VI) collagens and decrease of C/EBPs. Conclusion Our findings imply that various actions of ASC on adipogenesis through differential collagen expression may provide diverse applications of ASC to adipose tissue technology. PMID:24325571

  18. Experimental Study on How Human Lung Surfactant Protein SP-B1-25 is Oxidized by Ozone in the Presence of Fe(II) and Ascorbic Acid

    Science.gov (United States)

    Colussi, A. J.; Enami, S.; Hoffmann, M. R.

    2014-12-01

    We will report the results of experiments on the chemical fate of the human lung surfactant protein SP-B1-25 upon exposure to gaseous ozone in realistic aqueous media simulating the conditions prevalent in epithelial lining fluids in polluted ambient air. Our experiments consist of exposing aqueous microjets containing SP-B1-25, the natural antioxidant ascorbic acid, and the Fe2+ carried by most atmospheric fine particulates, under mild acidic conditions, such as those created by the innate lung host defense response. Reactants and the products of such interactions are detected via online electrospray ionization mass spectrometry. We will show that ascorbic acid largely inhibits the ozonation of SP-B1-25 in the absence of Fe2+, leading to the formation of an ascorbic acid ozonide (Enami et al., PNAS 2008). In the presence of Fe2+, however, the ozonide decomposes into reactive intermediates that result in the partial oxidation of SP-B1-25, presumable affecting its function as surfactant. We infer that these experimental results establish a plausible causal link for the observed synergic adverse health effects of ambient ozone and fine particulates

  19. 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 open...

  20. Effect of L (+) ascorbic acid and monosodium glutamate concentration on the morphology of calcium carbonate

    Science.gov (United States)

    Saraya, Mohamed El-shahte Ismaiel

    2015-11-01

    In this study, monosodium glutamate and ascorbic acid were used as crystal and growth modifiers to control the crystallization of CaCO3. Calcium carbonate prepared by reacting a mixed solution of Na2CO3 with CaCl2 at ambient temperature, (25 °C), constant Ca++CO3-- molar ratio and pH with stirring. The polymorph and morphology of the crystals were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results indicate that rhombohedral calcite was only formed in water without organic additives, and both calcite and spherical vaterite with various morphologies were produced in the presence of monosodium glutamate. The content of vaterite increased as the monosodium glutamate increased. In addition, spherical vaterite was obtained in the presence of different concentrations of ascorbic acid. The spherical vaterite posses an aggregate shape composed of nano-particles, ranging from 30 to 50 nm as demonstrated by the SEM and TEM analyses. Therefore, the ascorbic stabilizes vaterite and result in nano-particles compared to monosodium glutamate.

  1. Improvement of development of equine preantral follicles after 6 days of in vitro culture with ascorbic acid supplementation.

    Science.gov (United States)

    Gomes, R G; Lisboa, L A; Silva, C B; Max, M C; Marino, P C; Oliveira, R L; González, S M; Barreiros, T R R; Marinho, L S R; Seneda, M M

    2015-09-15

    The aim of this study was to evaluate the effects of different concentrations of ascorbic acid (25, 50, and 100 ?g/mL) in supplemented minimum essential medium (MEM+) on the development of equine preantral follicles that were cultured in vitro for 2 or 6 days. The contralateral ovaries (n = 5) from five mares in seasonal anestrus were collected from a local abattoir. Nine ovarian tissue fragments of approximately 5 × 5 × 1 mm were obtained from each animal. One fragment was immediately fixed and subjected to histologic analysis (control group; Day 0), and the other eight were placed in PBS supplemented with penicillin (200 IU/mL) and streptomycin (200 mg/mL) at 4 °C for 1 hour (during transport to the laboratory). The fragments were cultured in situ for 2 days (D2) or 6 days (D6) in MEM+ or MEM+ plus ascorbic acid at three different concentrations, establishing the following nine groups: control; MEM+ (D2); MEM+ (D6); MEM+ 25 ?g/mL of ascorbic acid (D2); MEM+ 25 ?g/mL of ascorbic acid (D6); MEM+ 50 ?g/mL of ascorbic acid (D2); MEM+ 50 ?g/mL of ascorbic acid (D6); MEM+ 100 ?g/mL of ascorbic acid (D2); and MEM+ 100 ?g/mL of ascorbic acid (D6). The preantral follicles were classified according to their stage (primordial, primary, secondary, or antral) and their morphology (normal or abnormal). Slides (n = 951) including 4450 histologic sections were evaluated. Follicles were observed in only 4.85% (216 of 4450) of the histologic sections. Of the 407 follicles evaluated, 120 were in the primordial stage and 287 were in different developmental stages; additionally, 43.5% were morphologically normal. After 6 days of culture, the groups cultured with 50 and 100 ?g/mL of ascorbic acid differed in terms of follicular development compared with the other groups. On the basis of occurrence of follicular development and the presence of viable follicles, it can be concluded that a positive effect of culture for 6 days in MEM+ supplemented with 50 and 100 ?g/mL of ascorbic acid was observed on equine ovarian fragments. PMID:26074067

  2. Comparison of ascorbic acid biosynthesis in different tissues of three non-heading Chinese cabbage cultivars.

    Science.gov (United States)

    Ren, Jun; Chen, Zhongwen; Duan, Weike; Song, Xiaoming; Liu, Tongkun; Wang, Jianjun; Hou, Xilin; Li, Ying

    2013-12-01

    Ascorbic acid (L-AsA) is an important antioxidant in plants and humans. Vegetables are one of the main sources of ascorbic acid for humans. For instance, non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino) is considered as one of the most important vegetables in south China. To elucidate the mechanism by which AsA accumulates, we systematically investigated the expression profiles of D-mannose/L-galactose pathway-related genes. We also investigated the recycling-related genes and AsA contents in different tissues of three non-heading Chinese cabbage cultivars, 'Suzhouqing', 'Wutacai' and 'Erqing' containing different amounts of AsA. Our results showed that six genes [D-mannose-6-phosphate isomerase 1 (PMI1), GDP-L-galactose phosphorylase 1 (GGP1), GGP2, GGP4, GDP-mannose-3', 5'-epimerase1 (GME1), and GME2] were expressed at high level and ascorbate oxidase (AAO) was expressed at low level. This expression pattern contributes, at least partially, to higher AsA accumulation in the leaves and petioles than in the roots. Eight genes (PMI1, GME, GGP, L-galactose-1-phosphate phosphatase, L-galactose dehydrogenase, L-galactono-1, 4-lactone dehydrogenase, monodehydroascorbate reductase 1, and glutathione reductase1) were also expressed at high level; AAO and ascorbate peroxidase (APX) were expressed at low level. This expression pattern may similarly contribute to higher AsA accumulation in 'Wutacai' and 'Suzhouqing' than in 'Erqing'. Therefore, the high expression levels of PMI, GME, and GGP and the low expression level of AAO contributed to the high AsA accumulation in non-heading Chinese cabbage. PMID:24157701

  3. 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.

  4. 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.

  5. 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

  6. 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 epinephrine hydrochloride injection when contain AA and UA, which also shows good recovery for determination of EP in some biological fluids.

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

    Science.gov (United States)

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

    2013-05-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  10. Exposure to ?-Tocopherol, Lutein or Ascorbic Acid improve Cumulus Expansion, Viability and Maturation of Swine Oocytes

    Directory of Open Access Journals (Sweden)

    Ileana Miclea

    2010-05-01

    Full Text Available Protection of the fatty acid and lipid components of oocytes that render them susceptible to free radical or other oxidative injury may prevent the damage currently associated with culture. The goal of this study was to establish the influence of several ?-tocopherol, lutein and ascorbic acid concentrations on swine oocyte maturation, viability and the function of cumulus cells in order to improve culture media. Pig oocytes were cultured for 45 hours at 37°C in 5% CO2 atmosphere; in M199 containing several ?-tocopherol (5, 10, 20, 40, 80 ?M, lutein (2.5, 4, 5, 8, 10 ?M or ascorbic acid (50, 150, 250, 500, 750 ?M concentrations and cumulus expansion was assessed. Afterwards oocytes were coloured using FDA, PI and Hoechst 33258. The differences between treatments were analyzed by the analysis of variance and interpreted using the Newman-Keuls method. When cultured in ?-tocopherol supplemented medium the number of expanded COCs to be scored as 3 was significantly greater (p<0.05 for the 5 and 40 ?M concentrations. The addition of 8 ?M lutein to the maturation medium lead to a significant (p<0.05 increase in the number of COCs that were scored at 4. For both ?-tocopherol and lutein additions the numbers of oocytes stained by FDA, as well as those stained by Hoechst were greater than the control without being statistically significant. When cultured in 150 and 500 ?M ascorbic acid the percentages of COCs scored at 4 were significantly lower (p<0.05 than the control. Also, significantly (p<0.05 fewer oocytes were stained with FDA when matured in 500 ?M. Differences between the control and the several concentrations were significant (p<0.05 for 150 and 750 ?M and distinctly significant (p<0.01 for 250 ?M.

  11. 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

  12. 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.

  13. Ultraviolet-induced oxidation of ascorbic acid in a model juice system: identification of degradation products.

    Science.gov (United States)

    Tikekar, Rohan V; Anantheswaran, Ramaswamy C; Elias, Ryan J; LaBorde, Luke F

    2011-08-10

    Degradation products of ultraviolet (UV-C, 254 nm) treated ascorbic acid (AA) are reported. Analysis by high-performance liquid chromatography-mass spectroscopy (HPLC-MS) conducted in a 0.5% malic acid model juice system (pH 3.3) demonstrated increased degradation of AA above untreated controls with concomitant increases in dehydroascorbic acid (DHA) and 2,3-diketogulonic acid (DKGA) levels. Electron spin resonance (ESR) spectroscopy studies, conducted in phosphate buffer (pH 7.0) to increase detection sensitivity, demonstrated that ascorbyl radical (AA•) formation occurs simultaneously with AA degradation. Consistent with a previous study in which UV treatments were shown to accelerate dark storage degradation, AA• radicals continued to form for up to 200 min after an initial UV treatment. Results from this study suggest that the mechanism for UV-induced degradation is the same as the general mechanism for metal-catalyzed oxidation of AA in juice. PMID:21699245

  14. 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

  15. 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.

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

    OpenAIRE

    Devaney R. do Carmo; Ricardo M. da Silva; NELSON R. STRADIOTTO

    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 decrease...

  17. Effects of lighting schedule and ascorbic acid on performance and tibiotarsus bone characteristics in broilers

    OpenAIRE

    YILDIZ, Hüseyin; Petek, Metin; Sönmez, Gürsel; ARICAN, ?lker; YILMAZ, Bestami

    2009-01-01

    This study was conducted to determine the effects of 2 lighting programs (continuous: 24 h light:0 h dark; intermittent: 12 h daylight followed by 3 cycles of 1 h light, and then 3 h dark during the night) and 3 ascorbic acid supplementations (0, 200, and 400 mg/L added to water) on broiler performance, bone characteristics, and the incidence of tibial dyschondroplasia. One-day-old male commercial (Ross PM3) broiler chicks (600) were divided into 6 treatment groups (2 × 3) with random replica...

  18. 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.

  19. Stimulation of hepatocyte growth factor production by ascorbic acid and its stable 2-glucoside.

    Science.gov (United States)

    Wu, Y L; Gohda, E; Iwao, M; Matsunaga, T; Nagao, T; Takebe, T; Yamamoto, I

    1998-10-01

    Hepatocyte growth factor (HGF), a cytokine which is generally produced by mesenchymal cells, has mitogenic, motogenic and morphogenic activities in epithelial cells and it also has tumor-suppressing activities. Induction of HGF production may be involved in organ regeneration, wound healing and embryogenesis. We examined the effects of ascorbic acid (AsA), which stimulates the proliferation of fibroblasts, and its stable derivative, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G), on HGF production by human skin fibroblasts. Basal HGF secretion was significantly stimulated by more than 0.1 mM AsA or AA-2G. Both vitamins synergistically enhanced HGF secretion stimulated by growth factors such as epidermal growth factor (EGF), platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF), cholera toxin and other inducers. Induction by EGF or bFGF was most markedly potentiated by the vitamins. HGF production by the KG-1 human leukemia cell line was also augmented by AsA or AA-2G. Another stable AsA derivative, ascorbic acid 2-phosphate (AA-2P) effectively promoted basal and EGF-induced HGF secretion by the fibroblasts, but ascorbic acid 2-sulfate (AA-2S) was much less effective. Intracellular AsA levels increased after the addition of AA-2G and AA-2P as well as AsA, but not after AA-2S. The effect of AA-2G was completely abrogated by the simultaneous addition of castanospermine, an alpha-glucosidase inhibitor, suggesting that the active form of AA-2G is AsA. Constitutive and EGF-induced HGF gene expression was also up-regulated after adding AsA or AA-2G to the cells. These results indicated that AsA acts alone or in synergy with several inducers to stimulate the production and gene expression of HGF in human skin fibroblasts and that the stable AsA derivative AA-2G is as effective as AsA in promoting HGF production. PMID:10984304

  20. Stability in fish feed and bioavailability to rainbow trout of two ascorbic acid forms

    OpenAIRE

    Skelbaek, T.; Andersen, Niels Gerner; Winning, M.; Westergaard, S.

    2011-01-01

    The stability in warm pelleted fish feed and the bioavailability to rainbow trout of crystalline ascorbic acid (AA) and a synthetic polymer-coated AA product (PCAA) were compared. The AA loss during pelleting was 29% for crystalline AA and 19% for PCAA. After 6 weeks at room temperature 73% of PCAA was still retained whereas less than 10% of crystalline AA was left. Rainbow trout were deprived of AA for 8 weeks, and then supplemented with AA from crystalline AA and PCAA, respectively. At the ...

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

    OpenAIRE

    JEM Peña; Vieira SL; López, 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...

  2. 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.

  3. Long-term ascorbic acid administration causes anticonvulsant activity during moderate and long-duration swimming exercise in experimental epilepsy.

    Science.gov (United States)

    Tutkun, Erkut; Arslan, Gokhan; Soslu, Recep; Ayyildiz, Mustafa; Agar, Erdal

    2015-01-01

    The benefits of regular exercise on brain health are undeniable. Long-term exercise increases the production of reactive oxygen species in brain. Therefore, athletes often consume antioxidant supplements to remedy exercise-related damage and fatigue during exercise. The aim of this study is to evaluate the role of ascorbic acid in the effects of different intensities of swimming exercise on the brain susceptibility to experimental epilepsy in rats. Ascorbic acid was administered intraperitoneally (ip) during three different swimming exercise programme for 90 days (15 min, 30 min, 90 min/day). The anticonvulsant activity regarding the frequency of epileptiform activity appeared in the 80 min after 500 units intracortical penicillin injection in 30 min and 90 min/day exercise groups. The administration of ascorbic acid (100 mg/kg, ip) did not alter the anticonvulsant properties seen in the in short-duration (15 min/day) swimming exercise group. The amplitude of epileptiform activity also became significant in the 110 and 120 min after penicillin injection in the moderate (30 min/day) and long duration (60 min/day) groups, respectively. The results of the present study provide electrophysiologic evidence that long-term administration of ascorbic acid causes anticonvulsant activities in the moderate and long-duration swimming exercise. Antioxidant supplementation such as ascorbic acid might be suggested for moderate and long-duration swimming exercise in epilepsy. PMID:26232995

  4. Voltammetric Oxidation of Ascorbic Acid Mediated by Multi-Walled Carbon Nanotubes/Titanium Dioxide Composite Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    P. Ganchimeg

    2011-01-01

    Full Text Available A MWCNT/TiO2 composite was modified onto glassy carbon electrode and fabricated by mechanical attachment, then applied to detection of ascorbic acid using cyclic voltammetry. Electrode responses were obtained for the oxidation of 0.5 mM ascorbic acid at the glassy carbon electrode modified with MWCNT, TiO2, MWCNT/TiO2 composite and an unmodified glassy carbon electrode. A well-defined and highly resolved oxidation peak of ascorbic acid at the MWCNT/TiO2/GCE with current enhancement and peak potential shift toward the origin being observed, this indicates evidence of electrocatalytic process. In comparison with other electrodes, the observed current enhancements at the MWCNT/TiO2/GCE were 1.3 folds higher than those obtained by MWCNT/GCE and 1.5 folds by a bare glassy carbon electrode. The response peak current revealed a good linear relationship of up to 2.5 mM ascorbic acid with correlation coefficient of 0.998. A good detection limit of 4.0 ?M was found using MWCNT/TiO2/GCE. Other usual parameters such as effect of pH, scan rate, temperature, supporting electrolyte and concentration of ascorbic acid were studied.

  5. Modelling the effects of transglutaminase and L-ascorbic acid on substandard quality wheat flour by response surface methodology

    Directory of Open Access Journals (Sweden)

    Šimurina Olivera D.

    2014-01-01

    Full Text Available In recent decade, there have been observed extreme variations in climatic conditions which in combination with inadequate agro techniques lead to decreased quality of mercantile wheat, actally flour. The application of improvers can optimise the quality of substandard wheat flour. This paper focuses to systematic analysis of individual and interaction effects of ascorbic acid and transglutaminase as dough strengthening improvers. The effects were investigated using the Response Surface Methodology. Transglutaminase had much higher linear effect on the rheological and fermentative properties of dough from substandard flour than L-ascorbic acid. Both transglutaminase and L-ascorbic acid additions had a significant linear effect on the increase of bread specific volume. Effects of transglutaminase and ascorbic acid are dependent on the applied concentrations and it is necessary to determine the optimal concentration in order to achieve the maximum quality of the dough and bread. Optimal levels of tested improvers were determined using appropriate statistical techniques which applied the desirability function. It was found that the combination of 30 mg/kg of transglutaminase and 75.8 mg/kg of L-ascorbic acid achieved positive synergistic effect on rheological and fermentative wheat dough properties, as well on textural properties and specific volume of bread made from substandard quality flour.

  6. Betalain, Acid Ascorbic, Phenolic Contents and Antioxidant Properties of Purple, Red, Yellow and White Cactus Pears

    Directory of Open Access Journals (Sweden)

    Leonardo Martinez-Cardenas

    2011-09-01

    Full Text Available 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 < 0.05 and were lower than the average antiradical activities in red and purple cultivars. The red cactus pear from the state of 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 (R2 = 0.90 and ascorbic acid (R2 = 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•.

  7. 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.

  8. 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.

  9. Calcium and ascorbic acid affect cellular structure and water mobility in apple tissue during osmotic dehydration in sucrose solutions.

    Science.gov (United States)

    Mauro, Maria A; Dellarosa, Nicolò; Tylewicz, Urszula; Tappi, Silvia; Laghi, Luca; Rocculi, Pietro; Rosa, Marco Dalla

    2016-03-15

    The effects of the addition of calcium lactate and ascorbic acid to sucrose osmotic solutions on cell viability and microstructure of apple tissue were studied. In addition, water distribution and mobility modification of the different cellular compartments were observed. Fluorescence microscopy, light microscopy and time domain nuclear magnetic resonance (TD-NMR) were respectively used to evaluate cell viability and microstructural changes during osmotic dehydration. Tissues treated in a sucrose-calcium lactate-ascorbic acid solution did not show viability. Calcium lactate had some effects on cell walls and membranes. Sucrose solution visibly preserved the protoplast viability and slightly influenced the water distribution within the apple tissue, as highlighted by TD-NMR, which showed higher proton intensity in the vacuoles and lower intensity in cytoplasm-free spaces compared to other treatments. The presence of ascorbic acid enhanced calcium impregnation, which was associated with permeability changes of the cellular wall and membranes. PMID:26575708

  10. 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)

  11. A novel method for the determination of ascorbic acid and antioxidant capacity in Opuntia ficus indica using in vivo microdialysis.

    Science.gov (United States)

    Pretti, L; Bazzu, G; Serra, P A; Nieddu, G

    2014-03-15

    A simple and rapid method was developed for in vivo simultaneous determination of ascorbic-acid and antioxidant capacity in microdialysates from cladodes of Opuntia ficus-indica (L.) Miller. The method is verified in water-stressed plants, as compared with a well-watered test controls. The microdialysis probe construction and insertion procedure was specifically developed to minimise the tissue trauma of the plant and to obtain optimal dialysis performance. Microdialysis was performed using a flow rate of 3 ?L/min and the samples were analysed by HPLC coupled to electrochemical detection of ascorbic-acid and DPPH-determined antioxidant capacity. Our data indicate exponential decay of the concentrations of the analysed compounds as a function of microdialysis sampling time. Water-stressed Opuntia show decreased ascorbic acid levels and increased the others antioxidants. PMID:24206696

  12. 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)

  13. Association of Lactobacillus crispatus with fructo-oligosaccharides and ascorbic acid in hydroxypropyl methylcellulose vaginal insert.

    Science.gov (United States)

    Vitali, Beatrice; Abruzzo, Angela; Parolin, Carola; Palomino, Rogers Alberto Ñahui; Dalena, Francesco; Bigucci, Federica; Cerchiara, Teresa; Luppi, Barbara

    2016-01-20

    The aim of this work was to develop a synbiotic vaginal insert containing the probiotic strain Lactobacillus crispatus BC5, the prebiotic substrate fructo-oligosaccharide and the antioxidant agent ascorbic acid, for the prophylaxis and therapy of vaginal infections. Mucoadhesive in situ gelling vaginal inserts based on hydroxypropyl methylcellulose were prepared by freeze-drying, stored at +2-8°C for 90 days and characterized in terms of technological and functional properties. Complete survival of L. crispatus BC5 was found immediately after insert preparation (96.08%) as well as after 90 days of storage (95.82%) in the vaginal inserts containing fructo-oligosaccharide, ascorbic acid and skimmed milk. Synbiotic inserts showed improved mucoadhesion ability (from three- to five-fold) with respect to a standard formulation based on hydroxypropyl methylcellulose alone. Moreover, inserts allowed to modulate lactobacilli release in virtue of the different amounts of fructo-oligosaccharide. Finally, antimicrobial activity was exerted by L. crispatus BC5 released from the vaginal formulation. PMID:26572459

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

    International Nuclear Information System (INIS)

    Re-188 labeled RC-160 [ cyclic NH2-(D)-Phe-Cys-Tyr-(D)-Trp-Lys-Val-Cys-Trp-NH2 ] 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 188Re-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, 188Re-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 NH2-(D)-Phe-CysTyr-(D)-Trp-Orn-Thr-Pen-Thr-ol], a ?-opiod-receptor antagonist used as a negative control compound, was also determined in vitro and in vivo using NCI-H69 cells as targets. 188Re-RC-160 demonstrated a higher amount of net binding in vitro and in vivo compared to 188ReCTOP. (orig.)

  15. 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)

  16. 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)

  17. 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.)

  18. Determining Total Phenolics, Anthocyanin Content and Ascorbic Acid Content in Some Plum Genotypes Grown in Ardahan Ecological Conditions

    Directory of Open Access Journals (Sweden)

    Z. T. ABACI

    2014-06-01

    Full Text Available In this study, total phenol content, total anthocyanin content, brix, pH, titrable acidity and total ascorbic acid content in the five plum genotypes cultivated in Ardahan City are determined and sustenance of the plums are revealed. Total phenol content was determined with folin-ciocalteu’s method, total anthocyanin content was determined with pH differential method and total ascorbic acid was determined with 2,6-dichlorophenolindophenol method.It is detected that the genotype with the highest brix content (%13.9 and lowest acidity (%0.98 is cancur, the genotype with the lowest brix content (%11 and highest acidity (%2.06 is wild plum, the genotype with the highest content of total anthocyanin, total phenolic substance and ascorbic acid is the wild plum and the genotype with the least content of these is the water plum. As a result of the study, it is revealed that the plum fruit has high levels of phenolic substance, anthocyanin and ascorbic acid content, so it has a high sustenance.

  19. "Oral ascorbic acid in combination with beta blockers in prevention of atrial fibrillation after Coronary Artery Bypass Graft "

    Directory of Open Access Journals (Sweden)

    Mousavi M

    2007-04-01

    Full Text Available Background: Adrenergic beta antagonists are not sufficient to prevent atrial fibrillation after coronary artery bypass graft (CABG. This study was designed to evaluate the effect of ascorbic acid as an adjunct to beta-blockers in prevention of post-CABG atrial fibrillation Methods: Patients who were more than 50 years old and scheduled to undergo CABG were included if they were treated with beta-blockers at least 1 week before surgery. Patients with previous history of atrial fibrillation, AV block, heart rate <50 /min, end-stage renal disease, severe pulmonary or liver disease and those who were taking digoxin or class I and III anti-arrhythmics or had pacemakers were not included. Ascorbic acid group were prescribed 2 gm of ascorbic acid, the night before the surgery, and 1 gm twice daily for 5 days after surgery. Beta blockers continued in both group after surgery. Telemetry monitoring was performed in ICU and Holter monitoring was performed for 4 days. Results: Fifty patients completed the study as ascorbic acid and 50 as control group. The population was 60.19 ± 7.14 years old and 67% were male. The incidence of postoperative atrial fibrillation was 4% in the ascorbic acid group and 26% in control group (odds ratio=0.119, 95% confidence interval: 0.025 to 0.558, P=0.002 Conclusion: Ascorbic acid is well-tolerated, relatively safe and seems effective. Therefore it can be prescribed as an adjunct to beta-blockers for prophylaxis of post-CABG atrial fibrillation.

  20. Modeling the combined effects of pH, temperature and ascorbic acid concentration on the heat resistance of Alicyclobacillus acidoterrestis.

    Science.gov (United States)

    Bahçeci, K Sava?; Acar, Jale

    2007-12-15

    In this study, thermal inactivation parameters (D- and z-values) of Alicyclobacillus acidoterrestris spores in McIlvaine buffers at different pH, apple juice and apple nectar produced with and without ascorbic acid addition were determined. The effects of pH, temperature and ascorbic acid concentration on D-values of A. acidoterrestris spores were also investigated using response surface methodology. A second order polynomial equation was used to describe the relationship between pH, temperature, ascorbic acid concentration and the D-values of A. acidoterrestris spores. Temperature was the most important factor on D-values, and its effect was three times higher than those of pH. Although the statistically significant, heat resistance of A. acidoterrestris spores was not so influenced from the ascorbic acid within the concentration studied. D-values in apple juice and apple nectars were higher than those in buffers as heating medium at similar pH. The D-values ranged from 11.1 (90 degrees C) to 0.7 min (100 degrees C) in apple juice, 14.1 (90 degrees C) to 1.0 min (100 degrees C) in apple nectar produced with ascorbic acid addition, and 14.4 (90 degrees C) to 1.2 min (100 degrees C) in apple nectar produced without ascorbic acid addition. However, no significant difference in z-values was observed among spores in the juices and buffers at different pH, and it was between 8.2 and 9.2 degrees C. The results indicated that the spores of A. acidoterrestris may survive in fruit juices and nectars after pasteurization treatment commonly applied in the food industry. PMID:17936391

  1. Electrochemical Sensing of Dopamine, Uric Acid and Ascorbic Acid Using tRGO-TiO2 Nanocomposites.

    Science.gov (United States)

    Rajamani, A R; Kannan, Rajesh; Krishnan, Sruthy; Ramakrishnan, S; Raj, S Mohan; Kumaresan, D; Kothurkar, Nikhil; Rangarajan, Murali

    2015-07-01

    This work reports a graphene-based nonenzymatic electrochemical sensing platform for the detection of dopamine (DA), uric acid (UA), and ascorbic acid (AA). Graphene oxide, synthesized by modified Hummers method, was thermally reduced in an induction furnace at 200 °C in an Ar-H2 atmosphere to obtain thermally reduced graphene oxide (tRGO). Nanocomposites of tRGO-TiO2 were obtained by a hydrothermal method, and were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD). FTIR spectra showed Ti-O-C peaks, indicating covalent linkage between the TiO2 nanoparticles and the reduced graphene oxide sheets. Glassy carbon electrode (GCE) was modified with the nanocomposite (tRGO-TiO2-GCE), and the modified electrode could detect dopamine (DA: 1 to 1000 µM), uric acid (UA: 1 to 900 µM), and ascorbic acid (AA: 10 to 1000 µM) in each other's presence over wide ranges, with adequate separation in peak potentials. Differential pulse voltammetry experiments yielded linear responses with sensitivities of 133.18, 33.96, and 155.59 µA mM(-1) cm(-2) for DA, UA, and AA, respectively. PMID:26373074

  2. 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 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

  3. Dye-sensitized photopolymerization of N,N -methylenebisacrylamide by initiation with eosin-ascorbic acid system

    Indian Academy of Sciences (India)

    Parthasarathy Tigulla; Uma Vuruputuri

    2004-03-01

    The dye-sensitized photopolymerization of N,N'-methylenebisacrylamide (MBA) in aqueous medium initiated by eosin-ascorbic acid (AH2) was studied at 25°C. The polymerization takes place only at higher concentration of AH2 (> 10-3 mol/L) and its rate increases rapidly as [AH2] is increased. The rate of polymerization is proportional to [MBA] and [AH2]. Kinetic results indicate that semi-quinone (DH) dye radical and semi-oxidized form ($A$) of ascorbic acid are unable to initiate polymerization. Formation of H2O2 is proposed and confirmed. A suitable mechanism is proposed in accordance with experimental results obtained.

  4. Effect of pre and post treatment of ascorbic acid on wheat and maize seeds exposed to gamma radiation

    International Nuclear Information System (INIS)

    Seeds treated with and grown in the presence of ascorbic acid (AA) showed reduction in germination, seedling height and chlorophyll content. The LD50 of AA was found to be 0.7 M and 10 M for wheat and maize, respectively. Pre-irradiation treatment of the seeds with ascorbic acid showed relatively increased germination, seedling height and chlorophyll content compared to that of AA treatment after irradiation. The protection rendered by the pre-treatment of AA may be due to AA acting as a free radical scavenger and thus protecting seeds from radiation induced damages. (author)

  5. 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.

  6. 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

  7. Impact of lipid oxidation-derived aldehydes and ascorbic acid on the antioxidant activity of model melanoidins.

    Science.gov (United States)

    Kitryt?, Vaida; Adams, An; Venskutonis, Petras Rimantas; De Kimpe, Norbert

    2012-12-01

    As the heat-induced formation of antioxidants throughout the Maillard reaction is known, this study was undertaken to evaluate the impact of lipid oxidation-derived aldehydes and ascorbic acid in Maillard model systems on the resulting antioxidant activity. For this purpose, various fractions of melanoidin-like polycondensation products were obtained from mixtures of amino acids (glycine, lysine, arginine) and lipid oxidation-derived aldehydes (hexanal, (E)-2-hexenal), in the presence or absence of glucose or ascorbic acid. All fractions showed a significant radical scavenging capacity (DPPH assay) and ferric reducing power (FRAP assay). The activity varied according to the composition of the model system tested, although some similar trends were discovered in both assays applied. The presence of lipid oxidation products in the browning products augmented the antioxidant activity in specific cases. For instance, the combined presence of arginine, hexanal and glucose in heated model systems resulted in a significantly higher antioxidant capacity. With an exception of ascorbic acid-containing model systems, melanoidin-like polycondensation products possessed significantly stronger antioxidant activities than the corresponding unheated initial reactant mixtures. Water-soluble high molecular weight (>12kDa) and nonsoluble fractions comprised the major part of the antioxidants derived from amino acid/lipid oxidation product model systems, with or without glucose or ascorbic acid. PMID:22953854

  8. Mechanism of degradation and discoloration reaction of L-ascorbic acid

    International Nuclear Information System (INIS)

    The mechanisms of decomposition and coloration reaction of L-ascorbic acid are reviewed. At the initial stage of the decomposition, it can be classified roughly into oxidative and non-oxidative processes of decomposition. ASA forms furfural by being heated and decomposed in strong acid. The mechanism of the production of furfural at varying pH in acidic region was discussed. Furfural was produced through the enol form of 3-deoxy-L-pentosulose(3DP). 3DP seemed to be produced by two different routes: the one route consists of successive reactions from ASA through lactone ring-opening, dehydration, decarboxylation, to 3DP, and the other consists of reactions from the 3-keto form of ASA, through lactone ring-opening, decarboxylation, and dehydration, to the enol form of 3DP. ASA is easily reduced and decomposed through dehydro-ASA(DHA) by the presence of an oxidizing agent. The decomposition of DHA is discussed in cases of the systems of DHA alone, DHA and ?-aminoacid, and DHA and amine. DHA was decomposed by the same reaction scheme as the decomposition of ASA and yielded 2-furoic acid. In the presence of an amino acid, DHA was decomposed by the Strecker decomposition, and yielded a red compound and a radical. In the presence of an amine, the discoloration reaction seemed to take place through radical reaction mechanism. The coloration reaction of ASA occurs in an acidic medium, and is accelerated by the oxidative process of decomposition. (Nishino, S.)

  9. 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.

  10. Novel halogenated 3-deazapurine, 7-deazapurine and alkylated 9-deazapurine derivatives of l-ascorbic or imino-l-ascorbic acid: Synthesis, antitumour and antiviral activity evaluations.

    Science.gov (United States)

    Stipkovi? Babi?, Maja; Makuc, Damjan; Plavec, Janez; Martinovi?, Tamara; Kraljevi? Paveli?, Sandra; Paveli?, Krešimir; Snoeck, Robert; Andrei, Graciela; Schols, Dominique; Wittine, Karlo; Mintas, Mladen

    2015-09-18

    Keeping the potential synergy of biological activity of synthetic anomalous derivatives of deazapurines and l-ascorbic acid (l-AA) in mind, we have synthesized new 3-, 7- and 9-deazapurine derivatives of l-ascorbic (1-4, 8-10, 13-15) and imino-l-ascorbic acid (5-7, 11, 12, 16-19). These novel compounds were evaluated for their cytostatic and antiviral activity in vitro against a panel of human malignant tumour cell lines and normal murine fibroblasts (3T3). Among all evaluated compounds, the 9-deazapurine derivative of l-AA (13) exerted the most potent inhibitory activity on the growth of CEM/0 cells (IC50 = 4.1 ± 1.8 ?M) and strong antiproliferative effect against L1210/0 (IC50 = 4.7 ± 0.1 ?M) while the 9-deazahypoxanthine derivative of l-AA (15) showed the best effect against HeLa cells (IC50 = 5.6 ± 1.3 ?M) and prominent effect on L1210/0 (IC50 = 4.5 ± 0.5 ?M). Furthermore, the 9-deazapurine derivative disubstituted with two imino-l-AA moieties (18) showed the best activity against L1210/0 tumour cells (IC50 = 4.4 ± 0.3 ?M) and the most pronounced antiproliferative effects against MiaPaCa-2 cells (IC50 = 5.7 ± 0.2 ?M). All these compounds showed selective cytostatic effect on tumour cell lines in comparison with embryonal murine fibroblasts (3T3). When evaluating their antiviral activity, the 3-deazapurine derivative of l-AA (3) exhibited the highest activity against both laboratory-adapted strains of human cytomegalovirus (HCMV) (AD-169 and Davis) with EC50 values comparable to those of the well-known anti-HCMV drug ganciclovir and without cytotoxic effects on normal human embryonal lung (HEL) cells. PMID:26291038

  11. 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.

  12. Fabrication and characterisation of high performance polypyrrole modified microarray sensor for ascorbic acid determination

    Energy Technology Data Exchange (ETDEWEB)

    Samseya, J. [Alagappa University, Karaikudi, Tamil Nadu (India); Srinivasan, R., E-mail: sivarunjan@gmail.com [Central Electro Chemical Research Insititute, Karaikudi, Tamil Nadu (India); Chang, Yu-Tsern; Tsao, Cheng-Wen [Department of Cosmetic Applications, Taoyuan Innovation Institute of Technology, Taiwan (China); Vasantha, V.S. [Madurai Kamaraj University, Madurai, Tamil Nadu (India)

    2013-09-02

    Graphical abstract: -- Highlights: •Gold microelectrode array (Au/MEA) with electrode of 12 ?m diameter was fabricated by photolithography technique. •Subsequently, polypyrrole (Ppy) modified gold microarrays sensor (Ppy/Au/MEA) was prepared. •Ppy/Au/MEA used for ascorbic acid determination in the presence of different neurotransmitters. •The micro array exhibited wide linear range, very high sensitivity and very low LOD than the earlier reports. •It was used successfully to test ascorbic acid in different types real samples. -- Abstract: In this study, gold microelectrode array (Au/MEA) with electrode of 12 ?m diameter was fabricated by photolithography technique. Subsequently, polypyrrole (Ppy) modified gold microarrays sensor (Ppy/Au/MEA) was prepared by cyclic voltammetry technique. The deposition potential range and number of cycles were optimised in order to get optimum thickness of Ppy film. Scanning Electron Microscope and Atomic Force Microscope investigations reveal that Ppy coating formed at 3 cycles is porous with thickness of 1.5 ?m which exhibiting high catalytic current for ascorbic acid (AA) in square wave technique (SWV). In contrast to earlier sensors designs, these Ppy/Au/MEA sensors exhibits lower detection limit (LOD) of 10 nm towards AA at physiological conditions. It also exhibits enhanced sensitivity (2.5 mA cm{sup ?2} mM{sup ?1}) and long range of linear detection limit from 10 nm to 2.8 mM. In the same way, polypyrrole modified macro Au (Ppy/Au/MA) biosensor was also fabricated and its electro catalytic property towards AA was compared with that of Ppy/Au/MEA. The Ppy/Au/MA exhibits sensitivity of only 0.27 mA cm{sup ?2} mM{sup ?1}, LOD of 5 ?M and linear range of 10 ?M to 2.2 mM. Hence, our investigations indicate that the Ppy/Au/MEA could serve as highly sensitive sensor for AA than any of the earlier designs. So, the Ppy/Au/MEA electrode was utilised for determination AA in a wide variety of real samples.

  13. Fabrication and characterisation of high performance polypyrrole modified microarray sensor for ascorbic acid determination

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Gold microelectrode array (Au/MEA) with electrode of 12 ?m diameter was fabricated by photolithography technique. •Subsequently, polypyrrole (Ppy) modified gold microarrays sensor (Ppy/Au/MEA) was prepared. •Ppy/Au/MEA used for ascorbic acid determination in the presence of different neurotransmitters. •The micro array exhibited wide linear range, very high sensitivity and very low LOD than the earlier reports. •It was used successfully to test ascorbic acid in different types real samples. -- Abstract: In this study, gold microelectrode array (Au/MEA) with electrode of 12 ?m diameter was fabricated by photolithography technique. Subsequently, polypyrrole (Ppy) modified gold microarrays sensor (Ppy/Au/MEA) was prepared by cyclic voltammetry technique. The deposition potential range and number of cycles were optimised in order to get optimum thickness of Ppy film. Scanning Electron Microscope and Atomic Force Microscope investigations reveal that Ppy coating formed at 3 cycles is porous with thickness of 1.5 ?m which exhibiting high catalytic current for ascorbic acid (AA) in square wave technique (SWV). In contrast to earlier sensors designs, these Ppy/Au/MEA sensors exhibits lower detection limit (LOD) of 10 nm towards AA at physiological conditions. It also exhibits enhanced sensitivity (2.5 mA cm?2 mM?1) and long range of linear detection limit from 10 nm to 2.8 mM. In the same way, polypyrrole modified macro Au (Ppy/Au/MA) biosensor was also fabricated and its electro catalytic property towards AA was compared with that of Ppy/Au/MEA. The Ppy/Au/MA exhibits sensitivity of only 0.27 mA cm?2 mM?1, LOD of 5 ?M and linear range of 10 ?M to 2.2 mM. Hence, our investigations indicate that the Ppy/Au/MEA could serve as highly sensitive sensor for AA than any of the earlier designs. So, the Ppy/Au/MEA electrode was utilised for determination AA in a wide variety of real samples

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. Effects of ascorbic acid on interactions between ciprofloxacin and ferrous sulphate, sodium ferrous citrate or ferric pyrophosphate, in mice.

    Science.gov (United States)

    Motoya, T; Miyashita, M; Kawachi, A; Yamada, K

    2000-04-01

    The absorption of ciprofloxacin has been reported to be impaired by concomitant administration of ferrous sulphate. The effects of sodium ferrous citrate and ferric pyrophosphate, which have been used as extensively as ferrous sulphate, on the absorption of ciprofloxacin were compared with that of ferrous sulphate. The effects of ascorbic acid on the interactions between ciprofloxacin and each iron compound were studied in mice. Mice were treated orally with ciprofloxacin (50 mg kg(-1)) alone, the iron compound (ferrous sulphate, sodium ferrous citrate or ferric pyrophosphate; 50 mg elemental iron kg(-1)) alone, ciprofloxacin with each iron compound or ciprofloxacin in combination with each iron compound and ascorbic acid (250 mg kg(-1)). The maximum serum concentration of ciprofloxacin was significantly (P ferric pyrophosphate was administered along with ciprofloxacin. The addition of ascorbic acid did not affect the inhibitory effects of each iron compound on the absorption of ciprofloxacin. Ciprofloxacin did not affect the variation of serum iron levels after administration of each iron compound. The addition of ascorbic acid significantly (P ferric pyrophosphate, although it did not affect the levels after ferrous sulphate administration. The results suggest that sodium ferrous citrate and ferric pyrophosphate should not be administered with ciprofloxacin (as for ferrous sulphate) and that sodium ferrous citrate is converted to the ferric form more easily than ferrous sulphate. This difference in convertibility might contribute to a clinical difference between sodium ferrous citrate and ferrous sulphate. PMID:10813549

  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. SPECTROPHOTOMETRIC DETERMINATION OF RITONAVIR BY CONDENSATION METHOD USING NINHYDRIN AND ASCORBIC ACID

    Directory of Open Access Journals (Sweden)

    M.L.N.Acharyulu

    2013-02-01

    Full Text Available A simple and sensitive extractive visible spectrophotometric method for the assay ofRitonavir in pure and pharmaceutical Formulations based on the reaction between peptidegroup in RIT and Ninhydrin in the presence of ascorbic acid affords a blue violet coloured product (?max 560nm. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges (20-60 ?g/ml. The percent recoveries are obtained as 99.64 ±0.47 to 100.40 ±0.45 by proposed method and 99.51 ±0.25 to 99.92 ±0.20 by reference method for the formulations respectively. The method can be applied successfully for the estimation of the Ritonavir in the presence of other ingredients that are usually present in formulations. The method offers the advantage of rapidity, simplicity and sensitivity and low cost without the need for expensive instrumentation and reagents.

  1. 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.

    Full Text Available 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.

  2. 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

    2015-08-01

    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.

  3. 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?%.

  4. Silver nanoparticles prepared in presence of ascorbic acid and gelatin, and their electrocatalytic application

    Indian Academy of Sciences (India)

    Fereshteh Chekin; Somayeh Ghasemi

    2014-10-01

    In this paper, we reported a simple and low-cost procedure to synthesize silver nanoparticles (AgNPs) by using ascorbic acid as reducing agent and gelatin as stabilizer. The synthesized AgNPs were characterized by various means such as transmission electron microscope (TEM), powder X-ray diffraction (XRD) and energy-dispersive X-ray (EDX). TEM observations and XRD analysis demonstrated that the size of AgNPs is about 20 nm. Silver nanoparticles modified with carbon-paste electrode (AgNPs–CPE) displayed excellent electrochemical catalytic activities towards hydrogen peroxide (H2O2). The reduction overpotential of H2O2 was decreased significantly compared with those obtained at the bare CPE. The sensor responded linearly to hydrogen peroxide (H2O2) in the concentration of 10–350 M, with detection limit of 5.6 M at 3 using amperometry. The studied sensor exhibited good reproducibility and long-term stability.

  5. 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 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.

  6. Ascorbic acid is superior to silymarin in the recovery of ethanol-induced inflammatory reactions in hepatocytes of guinea pigs.

    Science.gov (United States)

    Abhilash, P A; Harikrishnan, R; Indira, M

    2013-12-01

    Both oxidative stress and inflammatory reactions play a major role in alcoholic liver fibrosis. We evaluated the efficacy of ascorbic acid (AA) and silymarin in the regression of alcohol-induced inflammation in hepatocytes of guinea pigs (Cavia porcellus). Animals were administered with ethanol at a daily dose of 4 g/kg body weight (b.wt) for 90 days. On the ninety-first day, ethanol administration was stopped and animals were divided into alcohol abstention group and silymarin- (25 mg/100 g b.wt) and AA- (25 mg/100 g b.wt) supplemented groups and maintained for 30 days. There was a significant increase in the activities of alanine aminotransferase, aspartate aminotransferase, and ?-glutamyl transpeptidase in the serum of the ethanol group. The intracellular reactive oxygen species (ROS) and expressions of cytochrome P4502E1 and nuclear factor ?B1, tumor necrosis factor-?, and transforming growth factor-?(1) in hepatocytes were significantly increased in ethanol group. The fibrotic markers ?-smooth muscle actin and ?(1)(I) collagen and activity of cytotoxicity marker caspase-3 were significantly increased and AA content was significantly reduced in hepatocytes of alcohol-treated guinea pigs. But the AA and silymarin supplementation significantly reduced these changes in comparison with alcohol abstention group. AA could induce greater reduction of inflammatory and fibrotic markers in hepatocytes than silymarin. This indicates that AA is superior to silymarin in inhibiting intracellular ROS generation and thereby reducing the ethanol-induced inflammation in hepatocytes. PMID:23653339

  7. 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

  8. Therapeutic Potential effects of pyridoxine and /or ascorbic acid on Microalbuminuria in diabetes mellitus patient's: a randomized controlled clinical study

    Directory of Open Access Journals (Sweden)

    Hayder M. Al-Kuraishy

    2013-06-01

    Full Text Available Objectives: This study aimed to evaluate the therapeutic potential effects of ascorbic acid or and pyridoxine on diabetic renal microalbumiuria. Methods: This was a cross-sectional study on patients with diabetes mellitus at Al-Yarmouk teaching hospital from January to December 2012, Iraq-Baghdad. Twenty one patients with diabetes mellitus (D.M, 8 IDDM and 13 IDDM were selected from, the duration of disease were ranged from 2-12 years for both type (10 females and 11males and all enrolled patients ages were ranged from 28-65years. The concentration of total protein in urine was calculated by a biuret colorimetric assay and the urine creatinine level was measured by a modified Jaffe test. Statistical analysis: results are expressed as mean ± SD, for comparisons of two groups, Student’s t-test was used and statistical significance was accepted at p values < 0.05. Results: pyridoxine produced significant reduction in urinary albumin:creatinine ratio in patients with Type ?? D.M with the current therapy p?0.05 except with glimepiride p ?0.05 while the Ascorbic acid showed significant effect on albumin:creatinine in patients with Type ?? D.M after six week of treatment p ?0.05except on patient that treated with glibenclamide or glimepiride p?0.05. Combined effects of ascorbic acid 500 mg/day and pyridoxine 40mg/day on urinary albumin:creatinine produced significant reduction in albumin: creatinine ratio in both Type ? D.M and Type ?? D.M p ?0.05. Conclusions: Dual synergistic effects of ascorbic acid and pyridoxine produced more beneficial effects than either ascorbic acid or pyridoxine in amelioration of diabetic microalbuminuric nephropathy.

  9. 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.

  10. Biomarkers of lead exposure in petrol station attendants and auto-mechanics in Abeokuta, Nigeria: effect of 2-week ascorbic acid supplementation.

    Science.gov (United States)

    Onunkwor, B; Dosumu, O; Odukoya, O O; Arowolo, T; Ademuyiwa, O

    2004-07-01

    In order to study the ameliorative effects of ascorbic acid in chronic lead poisoning, petrol station attendants and auto-mechanics in Abeokuta, Nigeria, who have been shown to be occupationally exposed to lead and university students (serving as control), were supplemented daily with 500mg ascorbic acid for 2 weeks. Blood and urine samples were collected from the subjects before and after ascorbic acid regimen and analysed for lead and biochemical effects associated with lead toxicity. The 2-week ascorbic acid supplementation resulted in a significant (P < 0.05) reduction in blood lead in the occupationally exposed subjects. The reduction in blood lead amounted to 57% in male petrol station attendants, 50% in female petrol station attendants and 44% in the auto-mechanics. Urinary excretion of lead increased remarkably in the occupationally exposed subjects (P < 0.05). The biochemical effects associated with the toxic effects of lead also responded positively to the ascorbic acid regimen. Plasma and urine aminolevulinic acid (ALA) were reduced significantly (P < 0.05) by as much as 55% and 57% respectively. Plasma calcium also increased significantly (P < 0.05) in the subjects. Decreased levels of reduced glutathione (GSH) and hemoglobin observed in the occupationally exposed subjects were reversed by ascorbic acid. Glutathione-S-transferase (GST) and catalase (CAT) activities were not affected. Our findings indicate that ascorbic acid may be useful as an economical and convenient prophylactic agent for lead poisoning. PMID:21782728

  11. Amelioration of High Cholesterol Diet Caused Lipids Accumulation in Hepatic Cells by Rutin and Ascorbic Acid

    Directory of Open Access Journals (Sweden)

    Abdulaziz M. Aleisa

    2013-04-01

    Full Text Available Non Alcoholic Fatty Liver Disease (NAFLD has become a very common metabolic disorder. It refers to a group of conditions where excess fats are deposited in hepatic cells. Several approaches have been considered for the management of NAFLD including dietary changes, which were reported to suppress hepatic lipids accumulation in previous studies. The present study was designed to investigate the possible synergistic effects of Rutin (RT and Ascorbic Acid (AA against lipids accumulation in hepatic cells of male Wistar albino rats. Thirty animals received freshly prepared experimental High Cholesterol Diets (HCD with or without RT and/or AA for 6 consecutive weeks. In hepatic tissues nucleic acids, total protein, Total Cholesterol (TC and Triglycerides (TG concentrations were measured. Histopathological changes were also observed. In hepatic cells, nucleic acids and total protein levels were significantly reduced in HCD alone fed group, quite the reverse, TC and TG levels increased. RT and/or AA supplementation along with HCD showed antilipidemic effects in hepatic cells while compared to only HCD group. Histopathological assessment of the liver sections revealed moderate degree of hepatotoxicity following HCD feedings and mild degree of hepatoxocity when combining either RT or AA with HCD, while HCD+RT+AA group had no such changes. The present data demonstrated that the degree of HCD induced hepatotoxicity is in positive correlation with hepatic lipids accumulations. Both RT and AA could reduce this toxicity through their antilipidaemic properties, which may be augmented by their combined intake.

  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. Plasma ascorbic acid concentrations and fat distribution in 19,068 British men and women in the European Prospective Investigation into Cancer and Nutrition Norfolk cohort study.

    OpenAIRE

    Canoy, D; Wareham, N.; Welch, A; Bingham, S.; Luben, R.; Day, N; Khaw, KT

    2005-01-01

    BACKGROUND: Antioxidants, such as ascorbic acid, play a role in scavenging free radicals to protect against oxidative endothelial damage. Excess fat may promote fatty acid oxidation and increase free radical concentrations, which could result in increased antioxidant use. Whether plasma ascorbic acid concentrations are associated with fat distribution remains unclear. OBJECTIVE: Our aim was to examine the association between abdominal obesity, as measured by the waist-to-hip ratio, and plasma...

  14. Ascorbic acid/saline eluant increases 188Re yields after ''wet'' storage of 188W/188Re generators

    International Nuclear Information System (INIS)

    We have evaluated several factors in an attempt to minimize the reduced yields observed after ''wet'' storage of 188W/188Re generators, which include the dispersion of 188W-tungstic acid in the alumina column bed by pre-mixing with silica gel, incorporation of cupric ion as an antioxidant in the adsorbent, and elution of the alumina columns with saline containing ascorbic acid. The results demonstrate that dispersion of the 188W-tungstic acid in a silica-alumina bed and the use of cupric ion do not significantly increase 188Re yields after weekend ''wet'' storage. In contrast, addition of ascorbic acid at concentrations as low as 0.01% in the saline eluant was found to be an effective method of maintaining good 188Re yields after ''wet'' weekend storage, resulting in Monday elution yields greater than 70%. Use of low concentrations of ascorbic acid is thus an effective alternative to drying the generator columns before storage. (author)

  15. Antiscorbutic activity of L-ascorbic acid 2-glucoside and its availability as a vitamin C supplement in normal rats and guinea pigs.

    Science.gov (United States)

    Yamamoto, I; Suga, S; Mitoh, Y; Tanaka, M; Muto, N

    1990-11-01

    Bioavailability of a newly-synthesized and chemically-stable 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) as a vitamin C supplement was investigated in rats and guinea pigs. Oral administration of AA-2G to the animals resulted in an increase of serum ascorbic acid (AA) levels. However, in these sera the intact form was not detectable by the high performance liquid chromatography (HPLC) method, indicating its hydrolysis through the process of absorption. After an intravenous injection of AA-2G, the intact form diminished rapidly from the serum, followed by prolonged and marked elevation of serum AA levels. Various tissue homogenates from rats and guinea pigs were examined for their releasing activity of AA from AA-2G. High activity was observed in kidney, small intestine and serum of rats and in small intestine and kidney of guinea pigs. These hydrolytic activities were completely inhibited by castanospermine, a specific alpha-glucosidase inhibitor, suggesting the participation of alpha-glucosidase in the in vivo hydrolysis of AA-2G. AA-2G was found to exhibit obvious therapeutic effect in scorbutic guinea pigs by its repeated oral administrations. These results indicate that AA-2G is a readily available source of vitamin C activity in vivo. PMID:2093127

  16. 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 CNTs’ toxicity is oxidative stress.

  17. 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.

  18. 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 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. 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.

  20. Mechanisms of the influence of UV irradiation on collagen and collagen-ascorbic acid solutions

    Directory of Open Access Journals (Sweden)

    A. Sionkowska

    2006-09-01

    Full Text Available The study of the influence of UV irradiation on collagen solutions has shown the destabilization of the collagen molecule by calorimetric method. It is reflected both in changes of thermodynamic parameters of transition (Tm, ΔH, Cp=f(t and in the appearance of a low temperature peak, that is practically irreversible against rescanning. All these indicate that the important defects in the molecule occur. The ESR measurements have shown that the above-mentioned thermal changes are connected with the occurrence of free radicals in solution under UV irradiation. They interact with proline (Pro residues of the protein with the appearance of secondary free radicals, with following migration to glycine (Gly residues. The emergence of the free radicals at the Pro and then at the Gly residues may cause the dramatic structural defect resulting from the UV irradiation, which significantly alters the network of hydrogen bonds in the triple helix of the collagen molecule. All this is connected with destabilization of the collagen molecule, because the defects in amino acid residues probably lead to cleavage of covalent bonds near the damaged sites maintaining the triple helical structure. The presence of ascorbic acid in collagen solution protects the collagen molecule from occurring of secondary free radicals.

  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. Improved regeneration potential of fibroblasts using ascorbic acid-blended nanofibrous scaffolds.

    Science.gov (United States)

    Sridhar, Sreepathy; Venugopal, Jayarama Reddy; Ramakrishna, Seeram

    2015-11-01

    Two-dimensional scaffolds, three-dimensional scaffolds, and dermal substitutes are extensively used for biomedical applications in skin tissue regeneration. Not much explored synthetic polymers, like poly(l-lactic acid)-co-poly-(?-caprolactone) (PLACL), natural polymers, like silk fibroin (SF), and active inducing agents, such as ascorbic acid (AA) and tetracycline hydrochloride (TCH), represent a favorable matrix for fabricating dermal substitutes to engineer artificial skin for wound repair. The profligate nature of residing skin cells near the wound site is a paramount to survival and also regulating stem cells and other cellular networks and mechanical forces. PLACL/SF/TCH/AA nanofibrous scaffolds were fabricated by electrospinning and characterized for fiber morphology, membrane porosity, wettability, and significant subchains using Fourier transform infrared spectroscopy for culturing human-derived dermal fibroblasts. The PLACL, PLACL/SF, PLACL/SF/TCH, and PLACL/SF/TCH/AA scaffolds obtained diameters between 250 and 340 nm. The secretion of collagen by the laboratory-grown fibroblasts over the AA-blended scaffolds was found to be significantly higher compared with that of other scaffolds. The obtained results positively prove that introduction of naturally secreting compounds (AA) by the cells into the nanofibrous scaffolds will favor cell's microenvironment and eventually leads to complete tissue regeneration. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3431-3440, 2015. PMID:25903719

  3. 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 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.

  4. 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.

  5. 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.

  6. Direct electron transfer of ferritin in dihexadecylphosphate on an Au film electrode and its catalytic oxidation toward ascorbic acid

    International Nuclear Information System (INIS)

    Stable thin films were obtained by casting vesicle dispersion of dihexadecylphosphate (DHP) containing ferritin onto the nanometer Au film electrode. Ferritin in DHP films exhibited a well-defined current-potential curve. The voltammetric behavior of ferritin and the stability of the ferritin-DHP modified Au film electrode were investigated. UV-vis and reflctance absorbance infrared spectra indicated that ferritin retained near-native secondary structure in the DHP films. The loading and unloading of ferritin iron into the apoferritin shell were investigated by cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The results showed that iron exited the apoferritin shell when reduced, and entered into it when oxidized. Ferritin in DHP films exhibited a strong electrocatalytic activity toward the oxidation of ascorbic acid, which resulted in lowering 330 mV overpotential and greatly increasing the oxidation peak current. Based on this procedure, an amperometric method for the determination of ascorbic acid was proposed

  7. 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.

  8. Conclusion on the peer review of the pesticide risk assessment of the active substance L-ascorbic acid

    Directory of Open Access Journals (Sweden)

    European Food Safety Authority

    2013-04-01

    Full Text Available The conclusions of the European Food Safety Authority (EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State the Netherlands, for the pesticide active substance L-ascorbic acid are reported. The context of the peer review was that required by Commission Regulation (EU No 188/2011. The conclusions were reached on the basis of the evaluation of the representative uses of L-ascorbic acid as a fungicide on potato, glasshouse tomato and field and glasshouse flower bulbs. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and literature in the dossier peer reviewed, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

  9. 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 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

  10. Hyaluronic acid depolymerization by ascorbate-redox effects on solid state cultivation of Streptococcus zooepidemicus in cashew apple fruit bagasse.

    Science.gov (United States)

    de Macedo, André Casimiro; Santana, Maria Helena Andrade

    2012-05-01

    The cashew fruit (Anacardium occidentale L.) has been used as a promising agricultural resource for the production of low-molecular weight (M(W)) hyaluronic acid (HA) (10(4)-10(5) Da). The cashew juice is a rich source of vitamin C containing, 1.2-2.0 g L(-1). This work explores the effects of the initial concentration of the ascorbate on the solid fermentation of the juice-moisturized bagasse from the cashew apple fruit. The results show that the M(W) reduction of HA is proportional to the initial ascorbate concentration. The presence of ascorbate did not influence the Streptococcus zooepidemicus metabolism. However, the HA productivity was increased from 0.18 to 0.28 mg g(-1) h(-1) when the ascorbate concentration ranged from 1.7 to 10 mg mL(-1). These findings contribute to the controlled production of HA in a low M(W) range, which is important in cell signalization, angiogenesis and nanoparticles production. PMID:22806044

  11. SYNERGISTIC PROTECTIVE ROLE OF CAFFEINE AND L-ASCORBIC ACID ON LEAD INDUCED PROTEIN CONTENT ALTERATIONS IN VARIOUS TISSUES OF LEMELLIDENS CORRIANUS (LEA

    Directory of Open Access Journals (Sweden)

    Nawale S. P

    2015-02-01

    Full Text Available The present communication deals with individual and synergistic effectiveness of caffeine and L-ascorbic acid in lead induced toxicity in an experimental model, freshwater bivalve, Lamellidens corrianus.The effect on bivalve was studied under nine groups. From each treated and recovery groups, some bivalves were removed and protein contents in selected tissues of bivalves were estimated. The protein level was significantly decreased on exposure to lead while the decrease in presence of caffeine + ascorbic acid was less when exposed simultaneously than when exposed individually. During recovery protein contents recovered and the rate of recovery was faster in caffeine + ascorbic acid exposed bivalves as compared to those recovered individually and in normal water. The probable role of the caffeine (1,3,7- Trimethylexanthine and L-ascorbic acid is discussed in the paper.

  12. 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.

  13. Transcriptome Profiling of Tomato Fruit Development Reveals Transcription Factors Associated with Ascorbic Acid, Carotenoid and Flavonoid Biosynthesis

    Science.gov (United States)

    Ye, Jie; Hu, Tixu; Yang, Congmei; Li, Hanxia; Yang, Mingze; Ijaz, Raina; Ye, Zhibiao; Zhang, Yuyang

    2015-01-01

    Tomato (Solanum lycopersicum) serves as a research model for fruit development; however, while it is an important dietary source of antioxidant nutrients, the transcriptional regulation of genes that determine nutrient levels remains poorly understood. Here, the transcriptomes of fruit at seven developmental stages (7, 14, 21, 28, 35, 42 and 49 days after flowering) from two tomato cultivars (Ailsa Craig and HG6-61) were evaluated using the Illumina sequencing platform. A total of 26,397 genes, which were expressed in at least one developmental stage, were detected in the two cultivars, and the expression patterns of those genes could be divided into 20 groups using a K-mean cluster analysis. Gene Ontology term enrichment analysis indicated that genes involved in RNA regulation, secondary metabolism, hormone metabolism and cell wall metabolism were the most highly differentially expressed genes during fruit development and ripening. A co-expression analysis revealed several transcription factors whose expression patterns correlated with those of genes associated with ascorbic acid, carotenoid and flavonoid biosynthesis. This transcriptional correlation was confirmed by agroinfiltration mediated transient expression, which showed that most of the enzymatic genes in the ascorbic acid biosynthesis were regulated by the overexpression of each of the three transcription factors that were tested. The metabolic dynamics of ascorbic acid, carotenoid and flavonoid were investigated during fruit development and ripening, and some selected transcription factors showed transcriptional correlation with the accumulation of ascorbic acid, carotenoid and flavonoid. This transcriptome study provides insight into the regulatory mechanism of fruit development and presents candidate transcription factors involved in secondary metabolism. PMID:26133783

  14. Terminal ileum submucous plexus: Study of the VIP-ergic neurons of diabetic rats treated with ascorbic acid

    OpenAIRE

    Zanoni Jacqueline Nelisis; Hernandes Luzmarina; Bazotte Roberto Barbosa; Miranda Neto Marcílio Hubner de

    2002-01-01

    The aim of this study was to evaluate the effect of the ascorbic acid (AA) supplementation on the neurons that produce the vasoactive intestinal peptide (VIP) in the submucous plexus of the ileum of rat, four months after the induction of experimental diabetes mellitus with streptozotocin. Three groups of rats were used: C - control, D - diabetic, DA - diabetic receiving AA. We have measured the immunoreactivity and area of 80 cellular bodies of VIP-ergic neurons from each studied group. In t...

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

    OpenAIRE

    Andreea BRASOVAN; Codrea, Vlad; Vasilica MÂNDROC; Ramona CÂMPEAN; Neli OLAH

    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 ...

  16. 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.

  17. Stimulative Effects of Ascorbic Acid, Thiamin or Pyridoxine on Vicia faba Growth and Some Related Metabolic Activities

    Directory of Open Access Journals (Sweden)

    A. M. Hamada

    2000-01-01

    Full Text Available Soaking of bean seeds in 100 ppm ascorbic acid, thiamin or pyridoxine induced a stimulation effect on germination. Also, soaking of seeds or spraying of bean seedlings (25 day old with 100 ppm of each of these vitamins, stimulated fresh and dry weight, biosynthesis of photosynthetic pigment fractions and net photosynthetic rate. However, these treatments did not induce a considerable change in dark respiration.

  18. 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 concentration...

  19. Dynamical properties in uniform and periodic growth modes of ascorbic acid crystal domain from thin solution film

    OpenAIRE

    Yamazaki, Yoshihiro; Kikuchi, Mitsunobu; Toda, Akihiko; Wakita, Jun-ichi; Matsushita, Mitsugu

    2013-01-01

    There exists the threshold-sensitive dynamical transition between the uniform and the periodic growth modes in the domain growth of ascorbic acid crystals from its aqueous supersaturated solution film. The crystal growth induces the solution flow. Humidity controls the fluidity of the solution. The solution flow varies the film thickness. The threshold exists in the thickness of the solution film, and the crystal growth almost stops if the thickness becomes lower than the th...

  20. Optimum Efficiency of Photogalvanic Cell for Solar Energy Conversion: Lissamine Green B-Ascorbic Acid-NaLS System

    OpenAIRE

    Kishna Ram Genwa; Kewal Singh

    2013-01-01

    Photogalvanic cells are photoelectrochemical cells chargeable in light for solar energy conversion and storage. They may be energy source for the future, if their electrical performance is increased. In this study, a photosensitizer Lissamine green B, a reductant Ascorbic acid and a surfactant NaLS have been used in the photogalvanic cell. The generated photopotential and photocurrent are 850.0 mV and 375.0 ?A respectively. The conversion efficiency of the cell, fill factor and the cell perfo...

  1. Iron binding efficiency of polyphenols: Comparison of effect of ascorbic acid and ethylenediaminetetraacetic acid on catechol and galloyl groups.

    Science.gov (United States)

    Tamilmani, Poonkodi; Pandey, Mohan Chandra

    2016-04-15

    Dietary polyphenols are markedly studied for their antioxidant activity. They also have a negative impact on nutrition whereby they interfere with iron absorption. Common dietary polyphenols include: catechins, flavonols, flavanols, flavones, anthocyanins, proanthocyanidins and phenolic acids. Ascorbic acid (AA) and Ethylenediaminetetraacetic acid (EDTA) are commonly used to counter act this reaction and increase iron bioavailability. This study was aimed at determining the effect of AA and EDTA on the catechol or galloyl iron binding ability of pure phenolics, coffee and tea. Phenolic concentrations of 40, 80, 610, 240, 320, 400, 520 and 900?g/ml were tested against six levels of AA and EDTA. These effects were studied in detail using Multivariate Analysis of Variance (MANOVA) with the hypothesis that there would be one or more mean differences between the ratio of enhancer and the different concentrations of samples tested. AA was found to be more efficient than EDTA in a way that lesser quantity is required for completely overcoming negative iron binding effects of polyphenols and similar samples. PMID:26675868

  2. 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

  3. Electrochemical determination of ascorbic acid at p-phenylenediamine film-holes modified glassy carbon electrode

    Directory of Open Access Journals (Sweden)

    Olana Bikila Nagasa

    2015-01-01

    Full Text Available In this work the determination of ascorbic acid (AA at glassy carbon electrode (GCE modified with a perforated film produced by reduction of diazonium generated in situ from p-phenylenediamine (PD is reported. Holes were intentionally created in the modifier film by stripping a pre-deposited gold nanoparticles. The modified electrodes were electrochemically characterized by common redox probes: hydroquinone, ferrocyanide and hexamineruthenium(III. The cyclic voltammetric and amperometric response of AA using the modified electrodes was compared with that of bare GCE. The bare GCE showed a linear response to AA in the concentration range of 5 mM to 45 mM with detection limit of 1.656 mM and the modified GCE showed a linear response to AA in the concentration range of 5 ?M to 45 ?M with detection limit of 0.123 ?M. The effect of potential intereferents on amperometric signal of AA at the modified GCE was examined and found to be minimal. The inter-electrode reproducibility, stability, and accuracy were determined. The modified electrode showed excellent inter-electrode reproducibility, accuracy and stability. The modified electrode reported is a promising candidate for use in electroanalysis of AA.

  4. Regulation of ascorbic acid metabolism by blue LED light irradiation in citrus juice sacs.

    Science.gov (United States)

    Zhang, Lancui; Ma, Gang; Yamawaki, Kazuki; Ikoma, Yoshinori; Matsumoto, Hikaru; Yoshioka, Terutaka; Ohta, Satoshi; Kato, Masaya

    2015-04-01

    In the present study, the effects of red and blue LED lights on the accumulation of ascorbic acid (AsA) were investigated in the juice sacs of three citrus varieties, Satsuma mandarin, Valencia orange, and Lisbon lemon. The results showed that the blue LED light treatment effectively increased the AsA content in the juice sacs of the three citrus varieties, whereas the red LED light treatment did not. By increasing the blue LED light intensity, the juice sacs of the three citrus varieties accumulated more AsA. Moreover, continuous irradiation with blue LED light was more effective than pulsed irradiation for increasing the AsA content in the juice sacs of the three citrus varieties. Gene expression results showed that the modulation of AsA accumulation by blue LED light was highly regulated at the transcription level. The up-regulation of AsA biosynthetic genes (CitVTC1, CitVTC2, CitVTC4, and CitGLDH), AsA regeneration genes (CitMDAR1, CitMDAR2, and CitDHAR) and two GSH-producing genes (CitGR and CitchGR) contributed to these increases in the AsA content in the three citrus varieties. PMID:25711821

  5. 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.

  6. Polyethyleneimine-templated copper nanoclusters via ascorbic acid reduction approach as ferric ion sensor

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Jie; Ju, Yuyun; Liu, Juanjuan; Zhang, Huige [State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen, Xingguo, E-mail: chenxg@lzu.edu.cn [State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 730000 (China)

    2015-01-07

    Highlights: • A new method for synthesis of the BPEI-CuNCs is established. • A facile approach for Fe{sup 3+} ion sensing by fluorescence quenching is developed. • The method for Fe{sup 3+} sensing has high sensitivity and excellent selectivity. - Abstract: 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{sup 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{sup 3+} permitted in drinking water by the U.S. Environmental Protection Agency. The method was successfully applied to the detection of Fe{sup 3+} in tap water, Yellow River water and human urine samples with the quantitative spike recoveries ranging from 95.3% to 112.0%.

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

    Science.gov (United States)

    Cofan, Codru?a; Radovan, Ciprian

    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 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.

  8. Preparation of monodisperse aqueous microspheres containing high concentration of l-ascorbic acid by microchannel emulsification.

    Science.gov (United States)

    Khalid, Nauman; Kobayashi, Isao; Neves, Marcos A; Uemura, Kunihiko; Nakajima, Mitsutoshi; Nabetani, Hiroshi

    2015-09-01

    Monodisperse aqueous microspheres containing high concentrations of l-ascorbic acid with different concentrations of sodium alginate (Na-ALG) and magnesium sulfate (MgSO4) were prepared by using microchannel emulsification (MCE). The continuous phase was water-saturated decane containing a 5% (w/w) hydrophobic emulsifier. The flow rate of the continuous phase was maintained at 10?mL?h(-1), whereas the pressure applied to the disperse phase was varied between 3 and 25?kPa. The disperse phase optimized for successfully generating aqueous microspheres included 2% (w/w) Na-ALG and 1% (w/w) MgSO4. At a higher MgSO4 concentration, the generated microspheres resulted in coalescence and subsequent bursting. At a lower MgSO4 concentration, unstable and polydisperse microspheres were obtained. The aqueous microspheres generated from the MCs under optimized conditions had a mean particle diameter (dav) of 14-16?µm and a coefficient of variation (CV) of less than 8% at the disperse phase pressures of 5-15?kPa. PMID:26190217

  9. 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 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.

  10. Chronic nickel-induced DNA damage and cell death: the protection role of ascorbic acid.

    Science.gov (United States)

    Jia, Jie; Chen, Jie

    2008-06-01

    High consumption of nickel-containing products leads to more exposure of humans to nickel and its by-products. Except the lethal effect of acute nickel poison, chronic nickel exposure is also harmful to humans, but the mechanism of chronic nickel-induced cytotoxicity remains unclear. Here, we found that long-term exposure of Ni(2+) led to significant DNA fragmentation, cell death, and reactive oxygen species (ROS) generation in human leukemia HL-60 cells. Induction of Ni(2+) on DNA fragmentation and cell death could be prevented by the antioxidants ascorbic acid (ASA) or N-acetyl-cysteine (NAC), or enhanced by H(2)O(2), indicating the involvement of ROS generation in the chronic nickel cytotoxicity in cells. Long-term exposure of mice to low Ni(2+) also led to a significant increase in both the ROS generation in the serum and the DNA fragmentation in the peripheral blood mononuclear cells (PBMC), while coadministration of ASA with Ni(2+) together significantly decreased both the DNA fragmentation and the ROS generation. Collectively, these results proved that ROS generation is at least one mechanism of the cytotoxicity of chronic nickel exposure, while ASA is probably useful for people to prevent the chronic nickel cytotoxicity, especially for those who work or live near a mining area or a factory related with nickel. PMID:18214889

  11. 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.

  12. Elimination of Ascorbic Acid following High-Dose Infusion in Prostate Cancer Patients : A Pharmacokinetic Evaluation

    DEFF Research Database (Denmark)

    Kjær Nielsen, Torben; 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.

  13. Exogenous application of ascorbic acid alleviates chilling injury in apricot (Prunus armeniaca L. cv. Shahroudi flowers

    Directory of Open Access Journals (Sweden)

    Hassan Bayat

    2013-08-01

    Full Text Available One of the most important limiting factors in spread of apricot in Iran is late spring frost, which damages flower bud and decrease total yield of crop. It has been found that ascorbic acid (AA plays a beneficial role during plant response to chilling and freezing stresses. To evaluate the effects of AA on alleviating of cold stress, the flower buds of Prunus armeniaca L. cv. Shahroudi were sprayed at pink cluster stage with AS at 4 levels (0, 100, 200 and 300 mg. L-1 and were then exposed to artificial cold stress (4 h at –4 °C or without cold stress (+ 25°C. Experimental attributes including electrolyte leakage (EL of flower buds and percentage of damage of pistil, anthers and petals to temperature treatments were determined. The results showed that at - 4°C the lowest and highest percentage of damage and EL of flower buds were observed in application of 200 and 0 mg. L-1 AA, respectively. The highest and lowest percentage of damage of flower organs and EL were obtained in application of 300 and 200 mg. L-1 AA, respectively at + 25 °C. Based on the results of this experiment, AA alleviates the negative effect of cold stress on EL and flower organ damages in apricot cv. Shahroudi, depending on the concentrations of AA used.

  14. 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...

  15. Dietary vitamin A, ascorbic acid and ?-tocopherol affect the gonad development and reproductive performance of starry flounder Platichthys stellatus broodstock

    Science.gov (United States)

    Wang, Jiying; Li, Baoshan; Liu, Xudong; Ma, Jingjing; Wang, Shixin; Zhang, Limin

    2014-03-01

    The present trial was conducted with starry flounder Platichthys stellatus broodstock to evaluate the effects of dietary vitamin A, ascorbic acid, and ?-tocopherol on the gonadal development and reproductive performance. 8 000 IU/kg diet vitamin A (VA group), 500 mg/kg diet ascorbic acid (Vcpp group), or 250 mg/kg diet ?-tocopherol (?-TA group) was added into basal diet to create 3 vitamin experimental diets, respectively. Each diet was fed to 450 starry flounder broodstock for 104 days. Samples were collected weekly. The gonadosomatic index (GSI) of 3 vitamin experimental groups first decreased and then increased. Maximum GSI of Vcpp group was higher than that of ?-TA group but lower than that of VA group. The spawning periods of 3 vitamin experimental groups lasted 49, 56, and 45 days, respectively. No mature eggs were observed in the control group during the trial. The absolute fecundity (AF) and relative fecundity (RF) of ?-TA group was higher than that of Vcpp group but lower than that of VA group. The results suggest that different vitamins play different roles in the fish reproductive process. Vitamin A stimulated the maturation of the ovary, ascorbic acid prolonged the spawning period, and ?-tocopherol affected the development of the eggs.

  16. 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

  17. 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)

  18. Effect of ascorbic acid on fatigue of skeletal muscle fibres in long term cold exposed sprague dawley rats

    International Nuclear Information System (INIS)

    On exposure to prolonged cold temperature, the body responds for effective heat production both by shivering and non-shivering thermo genesis. Cold exposure increases the production of reactive oxygen species which influence the sarcoplasmic reticulum Ca/sup ++/ release from the skeletal muscles and affect their contractile properties. The role of ascorbic acid supplementation on force of contraction during fatigue of cold exposed skeletal muscles was evaluated in this study. Method: Ninety healthy, male Sprague Dawley rats were randomly divided into three groups of control, cold exposed, and cold exposed with ascorbic acid 500 mg/L supplementation mixed in drinking water. Group II and III were given cold exposure by keeping their cages in ice-filled tubs for 1 hr/day for one month. After one month, the extensor digitorum longus muscle was dissected out and force of contraction during fatigue in the skeletal muscle fibres was analysed on a computerised data acquisition system. Results: The cold exposed group showed a significant delay in the force of contraction during fatigue of skeletal muscle fibres compared to control group. Group III showed easy fatigability and a better force of contraction than the cold exposed group. Conclusions: Ascorbic acid increases the force of contraction and decreases resistance to fatigue in the muscles exposed to chronic cold. (author)

  19. Effects of ?-tocopherol and ascorbic acid in the severity and management of traumatic brain injury in albino rats

    Directory of Open Access Journals (Sweden)

    Gaafar M Ishaq

    2013-01-01

    Full Text Available Background: Traumatic brain injury (TBI is accompanied by substantial accumulation of biomarkers of oxidative stress and depletion of antioxidants reserve which initiate chain reactions that damage brain cells. The present study investigated the role of ascorbic acid and ?-tocopherol on the severity and management of TBI in rats. Materials and Methods: Wistar rats were subjected to closed head injury using an accelerated impact device. Rats were administered 45 mg/kg and 60 mg/kg body weight of ascorbic acid, ?-tocopherol or a combination of the two vitamins for 2 weeks pre- and post injury. Blood and brain tissue homogenates were analyzed for vitamin C, vitamin E, malondialdehyde, superoxide dismutase, and creatine kinase activities. Results: The results indicated that TBI caused significant (P < 0.05 decreased in vitamins C and E levels in the blood and brain tissue of TBI-untreated rats. The activities of superoxide dismutase in TBI rats were markedly reduced when compared with non traumatized control and showed a tendency to increased following supplementation with vitamins C and E. Supplementation of the vitamins significantly (P < 0.05 reduced malondialdehyde in the treatment groups compared with the TBI-untreated group. Conclusion: The study indicated that pre and post treatment with ascorbic acid and ?-tocopherol reduced oxidative stress induced by brain injury and effectively reduced mortality rate in rats.

  20. Frontier orbitals and transition states in the oxidation and degradation of L-ascorbic acid: a DFT study.

    Science.gov (United States)

    Yamabe, Shinichi; Tsuchida, Noriko; Yamazaki, Shoko; Sakaki, Shigeyoshi

    2015-04-01

    DFT calculations were carried out to investigate reaction paths of L-ascorbic acid (AAH2), hydroxyl radicals and water clusters. Frontier-orbital analyses were also performed to examine the regioselectivity of the OH? addition. Transition states of the electrolytic dissociation of AAH2 and intermediate carboxylic acids were found to have very small activation energies through proton transfers along hydrogen bonds. The ionized species (anions) are subject to the electrophilic attack of OH?. The elementary processes of AAH2 ? A?(-) ? dehydroascorbic acid ? diketogulonic acid ? threonic, oxalic, xylonic and lyxonic acids were investigated and discussed. The processes involved in the conversion of dehydroascorbic acid into a bicyclic hemiketal were also examined as a side-chain participating reaction. The oxidation and degradation of vitamin C up to threonic acid were described mainly as a donor (AAH2)-acceptor (OH?) reaction. PMID:25723880

  1. 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.)

  2. Ascorbic acid is a key participant during the interactions between chloroplasts and mitochondria to optimize photosynthesis and protect against photoinhibition

    Indian Academy of Sciences (India)

    Saikrishna Talla; Khateef Riazunnisa; Lolla Padmavathi; Pidakala Rajsheel; Agepati S Raghavendra

    2011-03-01

    The possible role of L-ascorbate (AsA) as a biochemical signal during the interactions between photosynthesis and respiration was examined in leaf discs of Arabidopsis thaliana. AsA content was either decreased as in AsA-deficient vtc1 mutants or increased by treatment with L-galactono-1, 4-lactone (L-GalL, a precursor of AsA; EC 1.3.2.3). In mutants, photosynthesis was extremely sensitive to both antimycin A (inhibitor of the cytochrome oxidase pathway [COX pathway]) and salicylhydroxamic acid (SHAM, inhibitor of the alternative pathway [AOX pathway]), particularly at high light conditions. Mitochondrial inhibitors lowered the ratio of reduced AsA to total AsA, at high light, indicating oxidative stress in leaf discs. Elevation of AsA by L-GalL decreased the sensitivity of photosynthesis at high light to antimycin A or SHAM, sustained photosynthesis at supraoptimal light and relieved the extent of photoinhibition. High ratios of reduced AsA to total AsA in L-GalL-treated leaf discs suggests that L-GalL lowers oxidative stress. The protection by L-GalL of photosynthesis against the mitochondrial inhibitors and photoinhibition was quite pronounced in vtc1 mutants. Our results suggest that the levels and redox state of AsA modify the pattern of modulation of photosynthesis by mitochondrial metabolism. The extent of the AOX pathway as a percentage of the total respiration in Arabidopsis mesophyll protoplasts was much higher in vtc1 than in wild type. We suggest that the role of AsA becomes pronounced at high light and/or when the AOX pathway is inhibited. While acknowledging the importance of the COX pathway, we hypothesize that AsA and the AOX pathway may complement each other to protect photosynthesis against photoinhibition.

  3. 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)

    Aria DOLATABADIAN

    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.

  4. 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

  5. Nickel inhibits mitochondrial fatty acid oxidation.

    Science.gov (United States)

    Uppala, Radha; McKinney, Richard W; Brant, Kelly A; Fabisiak, James P; Goetzman, Eric S

    2015-08-01

    Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation-the pathway by which fatty acids are catabolized for energy-in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with l-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 h), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1? (HIF1?). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1? knockout fibroblasts, implicating HIF1? as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis. PMID:26051273

  6. 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.

  7. The effect of long term administration of ascorbic acid on the learning and memory deficits induced by diabetes in rat

    Directory of Open Access Journals (Sweden)

    Parisa Hasanein

    2010-04-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: Ascorbic acid improves cognitive impairments in several experimental models. Diabetes causes learning and memory deficits. In this study we hypothesized that chronic treatment with ascorbic acid (100mg/kg, p.o would affect on the passive avoidance learning (PAL and memory in control and streptozocin-induced diabetic rats."n"nMethods: Diabetes was induced by a single i.p. injection of STZ (60mg/kg. The rats were considered diabetic if plasma glucose levels exceeded 250mg/dl on three days after STZ injection. Treatment was begun at the onset of hyperglycemia. PAL was assessed 30 days later. Retention test was done 24 h after training. At the end, animals were weighted and blood samples were drawn for plasma glucose measurement."n"nResults: Diabetes caused impairment in acquisition and retrieval processes of PAL and memory in rats. Ascorbic acid treatment improved learning and memory in control rats and reversed learning and memory deficits in diabetic rats. Ascorbic acid administration also improved the body weight loss and hyperglycemia of diabetics. Hypoglycemic and antioxidant properties of the vitamin may be involved in the memory improving effects of such treatment."n"nConclusion: These results show that ascorbic acid administration to rats for 30 days from onset of diabetes alleviated the negative influence of diabetes on learning and memory. Comparing with other nootropic drugs, vitamins have fewer side effects. Therefore, this regimen may provide a new potential alternative for prevention of the impaired cognitive functions associated with diabetes after confirming by clinical trials.

  8. Daytime of Sampling, Tooth-Brushing and Ascorbic Acid Influence Salivary Thiobarbituric Acid Reacting Substances – A Potential Clinical Marker of Gingival Status

    OpenAIRE

    Július Hodosy; Peter Celec

    2005-01-01

    Background. Salivary thiobarbituric acid reacting substances (TBARS) have been previously shown to correlate with the impairment of gingival tissue. Although the details on the origin and the composition of this heterogeneous group of compounds in saliva are unknown, the potential clinical usefulness makes necessary the studies of factors influencing the salivary TBARS levels. Aim. To observe the effects of daily dynamics, tooth-brushing and ascorbic acid administration on salivary TBARS leve...

  9. 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

  10. Determination of dopamine in presence of ascorbic acid and uric acid using poly (Spands Reagent) modified carbon paste electrode.

    Science.gov (United States)

    Veera Manohara Reddy, Y; Prabhakara Rao, V; Vijaya Bhaskar Reddy, A; Lavanya, M; Venu, M; Lavanya, M; Madhavi, G

    2015-12-01

    In this paper, we have fabricated a modified carbon paste electrode (CPE) by electropolymerisation of spands reagent (SR) onto surface of CPE using cyclic voltammetry (CV). The developed electrode was abbreviated as poly(SR)/CPE and the surface morphology of the modified electrode was studied by using scanning electron microscopy (SEM). The developed electrode showed higher electrocatalytic properties towards the detection of dopamine (DA) in 0.1M phosphate buffer solution (PBS) at pH7.0. The effect of pH, scan rate, accumulation time and concentration of dopamine was studied at poly(SR)/CPE. The poly(SR)/CPE was successfully used as a sensor for the selective determination of DA in presence of ascorbic acid (AA) and uric acid (UA) without any interference. The poly(SR)/CPE showed a good detection limit of 0.7?M over the linear dynamic range of 1.6?M to 16?M, which is extremely lower than the reported methods. The prepared poly(SR)/CPE exhibited good stability, high sensitivity, better reproducibility, low detection limit towards the determination of DA. The developed method was also applied for the determination of DA in real samples. PMID:26354279

  11. 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.

  12. Amperometric microsensor for direct probing of ascorbic acid in human gastric juice

    Energy Technology Data Exchange (ETDEWEB)

    Hutton, Emily A.; Pauliukaite, Rasa; Hocevar, Samo B. [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Ogorevc, Bozidar, E-mail: bogorevc@ki.s [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Smyth, Malcolm R. [National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland)

    2010-09-30

    This article reports on a novel microsensor for amperometric measurement of ascorbic acid (AA) under acidic conditions (pH 2) based on a carbon fiber microelectrode (CFME) modified with nickel oxide and ruthenium hexacyanoferrate (NiO-RuHCF). This sensing layer was deposited electrochemically in a two-step procedure involving an initial galvanostatic NiO deposition followed by a potentiodynamic RuHCF deposition from solutions containing the precursor salts. Several important parameters were examined to characterize and optimize the NiO-RuHCF sensing layer with respect to its current response to AA by using cyclic voltammetry, and scanning electron microscopy-energy dispersive X-ray spectroscopy methods. With the NiO-RuHCF coated CFME, the AA oxidation potential under acidic conditions was shifted to a less positive value for about 0.2 V (E{sub p} of ca. 0.23 V vs. Ag/AgCl) as compared to a bare CFME, which greatly improves the electrochemical selectivity. Using the hydrodynamic amperometry mode, the current vs. AA concentration in 0.01 M HCl, at a selected operating potential of 0.30 V, was found to be linear over a wide range of 10-1610 {mu}M (n = 22, r = 0.999) with a calculated limit of detection of 1.0 {mu}M. The measurement repeatability was satisfactory with a relative standard deviation (r.s.d.) ranging from 4% to 5% (n = 6), depending on the AA concentration, and with a sensor-to-sensor reproducibility (r.s.d.) of 6.9% at 100 {mu}M AA. The long-term reproducibility, using the same microsensor for 112 consecutive measurements of 20 {mu}M AA over 11 h of periodic probing sets over 4 days, was 16.1% r.s.d., thus showing very good stability at low AA levels and suitability for use over a prolonged period of time. Moreover, using the proposed microsensor, additionally coated with a protective cellulose acetate membrane, the calibration plot obtained in the extremely complex matrix of real undiluted gastric juice was linear from 10 to 520 {mu}M (n = 14, r = 0.998). These results demonstrated the unique featuring of the proposed NiO-RuHCF microsensor under acidic conditions with enhanced sensitivity and stability and proved its promising potentiality for direct amperometric probing of AA at physiological levels in real gastric juice environments.

  13. 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 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.

  14. Graphene decorated microelectrodes for simultaneous detection of ascorbic, dopamine, and folic acids by means of chemical vapor deposition

    Science.gov (United States)

    Namdar, N.; Hassanpour Amiri, M.; Dehghan Nayeri, F.; Gholizadeh, A.; Mohajerzadeh, S.

    2015-09-01

    In this paper, high quality and large area graphene layers were synthesized using thermal chemical vapour deposition on copper foil substrates. We use graphene incorporated electrodes to measure simultaneously ascorbic acid, dopamine and folic acid. Cyclic voltammetry and differential pulse voltammetry methods were used to evaluate electrochemical behaviour of the grown graphene layers. The graphene-modified electrode shows large electrochemical potential difference compared to bare gold electrodes with higher current responses. Also our fabricated electrodes configuration can be used easily for microfluidic analysis.

  15. Ratiometric Electrochemical Sensor for Effective and Reliable Detection of Ascorbic Acid in Living Brains.

    Science.gov (United States)

    Cheng, Hanjun; Wang, Xiaoyu; Wei, Hui

    2015-09-01

    The in vivo detection of ascorbic acid (AA), one of the physiologically important cerebral neurochemicals, is critical to probe and understand brain functions. Electrochemical sensors are convenient for AA detection. However, conventional electrochemical sensors usually suffer from several challenges, such as sluggish electron transfer kinetics for AA oxidation and poor reproducibility. To address these challenges, here we report ratiometric electrochemical sensors for effective and reliable detection of AA in living brains. The sensors were constructed by immobilizing preassembled thionine/Ketjen black (KB) nanocomposites onto glassy carbon (GC) electrodes or carbon fiber microelectrodes (CFMEs). The KB in the rationally functionalized nanocomposites efficiently facilitated AA oxidation at a relatively negative potential (?-0.14 V) without particular physical or chemical pretreatment, forming the basis of selective measurement of AA. With a well-defined and reversible pair of redox wave at -0.22 V, the assembled thionine acted as an internal reference to substantially alleviate the lab-to-lab, person-to-person, and electrode-to-electrode variations. The in vitro experiments demonstrated that the sensors exhibited extremely high reproducibility and stability toward selective measurement of AA. More, with operational simplicity and robustness in analytical performance, the designed sensors were successfully applied to in vivo effectively, selectively, and reliably monitor the dynamic change of cerebral AA associated with pathological processes (i.e., salicylate-induced tinnitus as the model) in living rats' brains. This study not only offers a new strategy for construction of ratiometric electrochemical sensors but also opens a new way for selective and reliable detection of neurochemicals for probing brain functions. PMID:26244714

  16. Modulatory effect of ascorbic acid on physiological responses of transported ostrich chicks

    Directory of Open Access Journals (Sweden)

    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.

  17. Modulatory effect of ascorbic acid on physiological responses of transported ostrich chicks

    Directory of Open Access Journals (Sweden)

    Minka N. Salka

    2012-02-01

    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. Application of ascorbic acid 2-glucoside as a solubilizing agent for clarithromycin: solubilization and nanoparticle formation.

    Science.gov (United States)

    Inoue, Yutaka; Yoshimura, Sachie; Tozuka, Yuichi; Moribe, Kunikazu; Kumamoto, Takuya; Ishikawa, Tsutomu; Yamamoto, Keiji

    2007-02-22

    Clarithromycin (CAM) was co-ground with l-ascorbic acid 2-glucoside (AA-2G), a newly developed food additive, to improve the solubility characteristics. The complete solubilizing effect of AA-2G was observed for the ground mixture with 1:1 molar ratio. When ground mixtures of CAM and AA-2G (2:1) were dispersed into water, not only the solubilization of CAM was observed but also nanoparticle formation with a mean particle diameter of 280 nm. The CAM particles obtained in this manner were stable in suspension for at least 7 days. Zeta potential analysis showed that positive charges on the particle surface may be contributing to the stability of the suspension. 1H NMR spectrum of CAM dissolved in a phosphate buffer (pH 5.5) showed a signal derived from the N,N-dimethylamino group at 2.73 ppm, while that of an equimolar ground mixture of CAM with AA-2G in D2O (pH 5.5) showed clearly two signals at 2.65 and 2.77 ppm derived from the splitting of the two methyl groups. The 13C NMR spectrum of the equimolar ground mixture dissolved in D2O exhibited two signals derived from N,N-dimethyl carbons of desosamine group at 37.2 and 42.3 ppm, whereas unprocessed CAM showed no resonance signal arising from those carbons. Moreover, the carbon resonance at 163 and 173 ppm arising from the ketone group in the CAM lactone ring shifted downfield to 177 and 180 ppm after the co-grinding with AA-2G. The formation of nanoparticles was only observed when CAM was co-ground with AA-2G in the molar ratio of 2:1, which might be attributable to a grinding-induced interaction in the solid-state via the ketone group in lactone ring of CAM. PMID:17055675

  19. Novel Spectrophotometric Methods for Determination of Salicylamide and Ascorbic acid in their binary mixture

    International Nuclear Information System (INIS)

    Simple, selective and precise four spectrophotometric methods were developed and validated for quantitative determination of Salicylamide (SAD) and Ascorbic acid (ASC, Vitamin C) in their binary mixture. Method A is Area under curve spectrophotometry, in which the area under curve in the wavelength ranges 225-245 nm and 265-285 nm were selected for determination of SAD and ASC. Method B is based on dual wavelength spectrophotometry, where ASC can be determined by difference in absorbance at 249.8 and 285.8 nm. On the same way; SAD is measured by difference in absorbance at 240.4 and 286.4 nm. Method C utilizes isoabsorptive point spectrophotometry where total concentration of SAD and ASC was calculated at their isoabsorptive points at 246.4 and 287 nm, while SAD concentration alone can be determined by first derivative spectrophotometry (1D) at 315.4 nm, then ASC concentration can be determined by subtraction. Method D is ratio subtraction spectrophotometry, where ASC can be determined by dividing the spectrum of the mixture by the spectrum of the SAD (as a divisor) followed by subtracting the constant absorbance value of the plateau region, then finally multiplying the obtained spectrum by the spectrum of the divisor. The developed methods have been successfully applied for determination of the studied drugs in different laboratory prepared mixtures and in their pharmaceutical formulation. Statistical comparison between the results obtained by applying the proposed methods and the reported HPLC method was done, and it was found that there was no significant difference between them regarding both accuracy and precision. (author)

  20. Simultaneous Determination of Ascorbic Acid, L-Dopa, Uric Acid, Insulin, and Acetylsalicylic Acid on Reactive Blue 19 and Multi-Wall Carbon Nanotube Modified Glassy Carbon Electrode

    Scientific Electronic Library Online (English)

    Navid, Nasirizadeh; Zahra, Shekari; Masoumeh, Tabatabaee; Masoud, Ghaani.

    2015-04-01

    Full Text Available A trifunctional electrochemical sensor was fabricated for simultaneous determination of ascorbic acid (AA), levodopa (LD), and insulin. This was done by modifying a glassy carbon electrode (GCE) with multi-walled carbon nanotubes and reactive blue 19 (RB-MWCNT-GCE). Cyclic voltammetry was used to in [...] vestigate the redox properties of this modified electrode. The electro-catalytic activity of the modified electrode was studied for the oxidation of AA, LD, and insulin. By differential pulse voltammetry (DPV), the detection limits of AA, LD, and insulin were estimated to be 0.45 µmol L -1, 0.37 µmol L-1, and 0.25 µmol L-1, respectively. In DPV measurements, the RB-MWCNT-GCE could separate the oxidation peak potentials of AA, LD, uric acid (UA), insulin, and acetylsalicylic acid (ASA) in a mixture. The practical utility of this modified electrode was demonstrated by detecting AA, LD, UA, insulin, and ASA in real samples.

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Promotion of IL-4- and IL-5-dependent differentiation of anti-mu-primed B cells by ascorbic acid 2-glucoside.

    Science.gov (United States)

    Ichiyama, Kenji; Mitsuzumi, Hitoshi; Zhong, Ming; Tai, Akihiro; Tsuchioka, Akihiro; Kawai, Saeko; Yamamoto, Itaru; Gohda, Eiichi

    2009-02-21

    The stable ascorbic acid derivative 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) was used to investigate the role of ascorbic acid (AA) in B cell differentiation in vitro. AA-2G is stable in a solution unlike AA but is hydrolyzed by cellular alpha-glucosidase to release AA. Mouse spleen B cells were primed for 2 days with an anti-mu antibody in the presence of interleukin (IL)-4 and IL-5 and then washed and recultured with AA-2G in the presence of IL-4 and IL-5. AA-2G, but not AA, dose-dependently increased IgM production, the greatest enhancement being 150% at concentrations of more than 0.5mM. In the absence of IL-4 and IL-5, primed B cells produced a negligible amount of IgM, and AA-2G had no effect. AA-2G-induced IgM production in the presence of IL-4 and IL-5 was inhibited by the alpha-glucosidase inhibitor castanospermine. Intracellular AA content, depleted during the priming period, increased by adding AA-2G at the start of reculture. Treatment of B cells with AA-2G resulted in an increase in the number of IgM-secreting cells, CD138-positive cells and CD45R/B220-negative cells. The number of viable cells in untreated cultures decreased gradually, but the decrease was significantly attenuated by AA-2G, resulting in about 70% more viable cells in AA-2G-treated cultures. AA-2G caused a slight but reproducible enhancement of DNA synthesis and a slight decrease in the number of cells with a sub-G1 DNA content. These results demonstrated that AA released from AA-2G enhanced cytokine-dependent IgM production in anti-mu-primed B cells and suggest that its effect is caused through promoting the differentiation of B cells to plasma cells and attenuating the gradual decrease in the number of viable cells. PMID:19201381

  4. High-sensitivity ascorbic acid sensor using graphene sheet/graphene nanoribbon hybrid material as an enhanced electrochemical sensing platform.

    Science.gov (United States)

    Lavanya, J; Gomathi, N

    2015-11-01

    A novel electrode material of graphene sheet/graphene nanoribbon (GS/GNR) hybrid material was developed by incorporating graphene nanoribbons into graphene nanosheets through simultaneous chemical reduction of graphene oxide sheets and graphene oxide ribbons. The structure and properties of synthesized GS/GNR were characterized by transmission electron microscope, scanning electron microscope, X-ray diffraction, Brunauer Emmett Teller measurements and Fourier transform infrared spectroscopy. This work compares the electro catalytic performance of the GS/GNR, chemically reduced graphene oxide sheets (CRGOS) and GS/carbon nanotube (CNT) by modifying the glassy carbon electrode (GCE) using ascorbic acid (AA) as analyte. The electrochemical impedance spectroscopy revealed that the charge transfer resistance of GS/GNR modified electrode was less than that of CRGOS modified electrode and bare GCE. The cyclic voltammetric sensing of GS/GNR modified electrode towards AA was negatively shifted (0.08 V) compared to CRGOS, GS/CNT modified electrode and bare GCE (0.222, 0.150 and 0.666 V). This catalytic oxidation allows an amperometric detection of AA with a detection limit of 230 nM and sensitivity of 22 nA ?M(-1) cm(-2). GS/GNR modified GCE exhibited a high selectivity for ascorbic acid in the presence of other interferents like dopamine, uric acid and citric acid. PMID:26452874

  5. 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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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

  7. 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.

  8. 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.

  9. Radiation protection by 6-palmitoyl ascorbic acid-2-glucoside: studies on DNA damage in vitro, ex vivo, in vivo and oxidative stress in vivo.

    Science.gov (United States)

    Chandrasekharan, Dhanya K; Kagiya, Tsutomu V; Nair, Cherupally Krishnan Krishnan

    2009-05-01

    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 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 conditions of ionizing-radiation exposure. PMID:19384055

  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 conditions of ionizing-radiation exposure. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Begum, Parvin [Laboratory of Environmental Medical Chemistry, Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810 (Japan); Fugetsu, Bunshi, E-mail: hu@ees.hokudai.ac.jp [Laboratory of Environmental Medical Chemistry, Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810 (Japan)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer MWNTs are selected for study of the systemic toxicity and the potential influence on red spinach. Black-Right-Pointing-Pointer Microscopic observation revealed some adverse effects on root and leaf. Black-Right-Pointing-Pointer Cell damage were detected on 15 days after the exposure to MWNTs. Black-Right-Pointing-Pointer ROS increase ceased once ascorbic acid was added into media. Black-Right-Pointing-Pointer 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{sup -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 CNTs' toxicity is oxidative stress.

  12. Ácido L-ascórbico: reações de complexação e de óxido-redução com alguns íons metálicos de transição / L-ascorbic acid: complexation and redox reactions with some transition metal ions

    Scientific Electronic Library Online (English)

    Adalgiza, Fornaro; Nina, Coichev.

    1998-10-01

    Full Text Available [...] Abstract in english The strong reducing action of L-ascorbic acid (Vitamin C) are of fundamental interest in biochemical and related process. The oxidation of ascorbic acid by molecular oxygen and others oxidants are of fundamental importance, involving the intervention of transition metal ions as catalysts and the for [...] mation transition metal complexes of ascorbic acid as intermediates. The present article is intended to cover some aspects of the reactions of ascorbic acid and related compounds involving some transition metal ions.

  13. 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.

  14. 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

    Directory of Open Access Journals (Sweden)

    Klingelhoeffer Christoph

    2012-05-01

    Full Text Available 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. Methods Effective concentration (EC50 values, which indicate the concentration of ascorbic acid that reduced the number of viable cells by 50%, were detected with the crystal violet assay. The level of intracellular catalase protein and enzyme activity was determined. Expression of catalase was silenced by catalase-specific short hairpin RNA (sh-RNA in BT-20 breast carcinoma cells. Oxidative cell stress induced apoptosis was measured by a caspase luminescent assay. Results The tested human cancer cell lines demonstrated obvious differences in their resistance to ascorbic acid mediated oxidative cell stress. Forty-five percent of the cell lines had an EC50?>?20?mmol/L and fifty-five percent had an EC50?50 of 2.6–5.5?mmol/L, glioblastoma cells were the most susceptible cancer cell lines analysed in this study. A correlation between catalase activity and the susceptibility to ascorbic acid was observed. To study the possible protective role of catalase on the resistance of cancer cells to oxidative cell stress, the expression of catalase in the breast carcinoma cell line BT-20, which cells were highly resistant to the exposure to ascorbic acid (EC50: 94,9?mmol/L, was silenced with specific sh-RNA. The effect was that catalase-silenced BT-20 cells (BT-20 KD-CAT became more susceptible to high concentrations of ascorbic acid (50 and 100?mmol/L. Conclusions Fifty-five percent of the human cancer cell lines tested were unable to protect themselves against oxidative stress mediated by ascorbic acid induced hydrogen peroxide production. The antioxidative enzyme catalase is important to protect cancer cells against cytotoxic hydrogen peroxide. Silenced catalase expression increased the susceptibility of the formerly resistant cancer cell line BT-20 to oxidative stress.

  15. Lack of promotion of urinary bladder carcinogenesis by sodium bicarbonate and/or L-ascorbic acid in male ODS/Shi-od/od rats synthesizing alpha 2 mu-globulin but not L-ascorbic acid.

    Science.gov (United States)

    Mori, S; Murai, T; Hosono, M; Machino, S; Makino, S; Chou, C; Fukushima, S

    1997-08-01

    The study was designed to investigate whether sodium bicarbonate (NaHCO3) and/or L-ascorbic acid (AsA) promote urinary bladder carcinogenesis in male ODS/Shi-od/od (ODS) rats, which, unlike male F344 rats, are resistant to sodium L-ascorbate (Na-AsA)-promoting effects. Whereas F344 rats can synthesize AsA and alpha 2 mu-globulin (A2 mu-G), only A2 mu-G in produced in ODS rats. The two strains were given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in their drinking water for 2 wk and then were fed basal CA-1 diet supplemented with 3% NaHCO3 plus 5% AsA (NaHCO3 + AsA), 3% NaHCO3, 5% AsA, or no chemicals for 32 wk. ODS rats given BBN-NaHCO3 or BBN-(NaHCO3 + AsA) had only a few small carcinomas in the urinary bladder, like those receiving BBN alone or BBN-AsA. In contrast, F344 rats administered BBN-NaHCO3 or BBN-(NaHCO3 + AsA) had many more, larger, carcinoma than animals of the same strain given BBN alone or BBN-AsA. AsA alone did not have any effect in either strain. Administration of NaHCO3 alone or NaHCO3 + AsA was associated with significant elevation of urinary pH and Na+ concentration to the same extent in both strains but, again, AsA alone was without effect. NaHCO3 + AsA and AsA alone increased the urinary concentration of total ascorbic acid in both strains but the observed levels wer lower in ODS rats. The results indicate that ODS rats are resistant to the modifying effects of NaHCO3 and/or AsA on two-stage urinary bladder carcinogenesis, and thus that the susceptibility to the promotional activity of sodium-salt-type compounds may be regulated by factors other than A2 mu-G-synthesizing ability and urinary levels of pH, Na+ and total ascorbic acid. PMID:9350223

  16. Effect of turmeric powder (Curcuma longa L.) and ascorbic acid on physical characteristics and oxidative status of fresh and stored rabbit burgers.

    Science.gov (United States)

    Mancini, Simone; Preziuso, Giovanna; Dal Bosco, Alessandro; Roscini, Valentina; Szendr?, Zsolt; Fratini, Filippo; Paci, Gisella

    2015-12-01

    The objective of this study was to evaluate the effect of Curcuma longa powder and ascorbic acid on some quality traits of rabbit burgers. The burgers (burgers control with no additives; burgers with 3.5g of turmeric powder/100g meat; burgers with 0.1g of ascorbic acid/100g meat) were analyzed at Days 0 and 7 for pH, color, drip loss, cooking loss, fatty acid profile, TBARS, antioxidant capacity (ABTS, DPPH and FRAP) and microbial growth. The addition of turmeric powder modified the meat color, produced an antioxidant capacity similar to ascorbic acid and determined a lower cooking loss than other formulations. Turmeric powder might be considered as a useful natural antioxidant, increasing the quality and extending the shelf life of rabbit burgers. PMID:26188362

  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. Electrocatalytic Determination of Ascorbic Acid Using Glassy Carbon Modified with Nickel(II) Macrocycle Containing Dianionic Tetraazaannulene Ligand

    OpenAIRE

    KHORASANI-MOTLAGH, Mozhgan; NOROOZIFAR, Meissam

    2004-01-01

    A symmetric Ni(II) tetraaza macrocycle modified glassy electrode shows electrocatalytic activity for the oxidation of L-ascorbic acid at pH 7. It was shown the peak potential shifted to the negative by 250 mV compared with that for the bare electrode in the cyclic voltammograms. The calibration curve was linear up to 5 mM with a detection limit of 2.5 \\times 10-4 mM and RSD% better than 2.8%. Excipients used as additives in pharmaceutical formulations and foods did not interfere in ...

  19. Volumetric properties of (ascorbic acid + polyethylene glycol 3350 + water) systems at T = (288.15, 298.15, and 308.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Melike [Chemistry Department, Akdeniz University, 07058 Antalya (Turkey); Ayranci, Erol, E-mail: eayranci@akdeniz.edu.t [Chemistry Department, Akdeniz University, 07058 Antalya (Turkey)

    2011-02-15

    Density and ultrasound speed were measured accurately for binary ascorbic acid-water and ternary ascorbic acid-water-polyethylene glycol 3350 (PEG3350) solutions at T = (288.15, 298.15, and 308.15) K. The data were used to evaluate thermodynamic properties as apparent molar volumes, V{sub {phi}}, and apparent molar isentropic compressions, K{sub S{Phi}}, of ascorbic acid in water and in aqueous PEG3350 solutions. Infinite dilution values of these parameters, V{sub {phi}}{sup 0} and K{sub S{Phi}}{sup 0}, were obtained from their plots as a function of molality and have been utilized in obtaining transfer volumes and transfer compressions of ascorbic acid from water to PEG3350 solutions at various weight percentages. All transfer volumes and compressions at infinite dilution were found to be positive, to increase with weight per cent of PEG3350 and to decrease with temperature. Apparent molar isobaric expansions at infinite dilution were derived from the temperature dependence of V{sub {phi}}{sup 0} values. The results were interpreted in terms of ascorbic acid-water-PEG3350 interactions.

  20. Volumetric properties of (ascorbic acid + polyethylene glycol 3350 + water) systems at T = (288.15, 298.15, and 308.15) K

    International Nuclear Information System (INIS)

    Density and ultrasound speed were measured accurately for binary ascorbic acid-water and ternary ascorbic acid-water-polyethylene glycol 3350 (PEG3350) solutions at T = (288.15, 298.15, and 308.15) K. The data were used to evaluate thermodynamic properties as apparent molar volumes, V?, and apparent molar isentropic compressions, KS?, of ascorbic acid in water and in aqueous PEG3350 solutions. Infinite dilution values of these parameters, V?0 and KS?0, were obtained from their plots as a function of molality and have been utilized in obtaining transfer volumes and transfer compressions of ascorbic acid from water to PEG3350 solutions at various weight percentages. All transfer volumes and compressions at infinite dilution were found to be positive, to increase with weight per cent of PEG3350 and to decrease with temperature. Apparent molar isobaric expansions at infinite dilution were derived from the temperature dependence of V?0 values. The results were interpreted in terms of ascorbic acid-water-PEG3350 interactions.

  1. Effects of ascorbic acid and glucose oxidase levels on the viability of probiotic bacteria and the physical and sensory characteristics in symbiotic ice-cream

    Directory of Open Access Journals (Sweden)

    M. B. Ak?n

    2015-05-01

    Full Text Available In this study, the effects of addition of different amounts of ascorbic acid and glucose oxidase on the properties of symbiotic ice cream were investigated. Ice-cream containing inulin (2 % (w/w was produced by mixing fortified milk fermented with probiotic strains with the ice-cream mixes containing different ascorbic acid and glucose oxidase concentrations (0.025, 0.05, 0.1 (w/w. The cultures were grown (37 °C, 12 h in UHT skimmed milk. The fermented milk was added to the ice-cream mix up to a level of 10 % w/w. Increasing the concentration of ascorbic acid stimulated the growth of Lactobacillus acidophilus LA-5 (L. acidophilus and Bifidobacterium animalis subsp. lactis BB-12 (Bifidobacterium BB-12. On contrary, increasing the concentration of glucose oxidase negatively affected the growth of L. acidophilus and Bifidobacterium BB-12. However, both, ascorbic acid and glucose oxidase concentration had no effect on physical and sensory properties of ice cream. The results suggested that the addition of ascorbic acid stimulated the growth of L. acidophilus and Bifidobacterium BB-12 and could be recommended for ice cream production.

  2. Losses of Ascorbic Acid During Storage of Fresh Tubers, Frying, Packaging and Storage of Potato Crisps from Four Kenyan Potato Cultivars

    Directory of Open Access Journals (Sweden)

    J.N. Kabira

    2011-01-01

    Full Text Available The ascorbic acid (AA, vitamin C levels of tubers was determined in four Kenyan potato cultivars (Dutch Robyjn, Tigoni, 393385.39 and 391691.96 grown under standard cultural conditions and the effect of storage on fresh tubers was evaluated. Tubers were processed into crisps and the effect of frying temperature, package type, storage temperature and time were also determined. There was significant (p=0.05 variation due to cultivar and storage condition was found to affect the levels of ascorbic acid in fresh tubers. There was significant (p=0.05 reduction on the level of ascorbic acid (45% on the average in all the cultivars when tubers were fried into crisps. Packaging type and storage temperature significantly (p=0.05 influenced the amount of ascorbic acid retained by crisps within the storage period. It is therefore important for processors to choose lower frying temperature and proper packaging for maximum vitamin C retention. Storage of potato crisps at temperatures beyond 30C results in lower levels of ascorbic acid retention.

  3. Regulation of fruit ascorbic acid concentrations during ripening in high and low vitamin C tomato cultivars

    Directory of Open Access Journals (Sweden)

    Mellidou Ifigeneia

    2012-12-01

    Full Text Available Abstract Background To gain insight into the regulation of fruit ascorbic acid (AsA pool in tomatoes, a combination of metabolite analyses, non-labelled and radiolabelled substrate feeding experiments, enzyme activity measurements and gene expression studies were carried out in fruits of the ‘low-’ and ‘high-AsA’ tomato cultivars ‘Ailsa Craig’ and ‘Santorini’ respectively. Results The two cultivars exhibited different profiles of total AsA (totAsA, AsA + dehydroascorbate and AsA accumulation during ripening, but both displayed a characteristic peak in concentrations at the breaker stage. Substrate feeding experiments demonstrated that the L-galactose pathway is the main AsA biosynthetic route in tomato fruits, but that substrates from alternative pathways can increase the AsA pool at specific developmental stages. In addition, we show that young fruits display a higher AsA biosynthetic capacity than mature ones, but this does not lead to higher AsA concentrations due to either enhanced rates of AsA breakdown (‘Ailsa Craig’ or decreased rates of AsA recycling (‘Santorini’, depending on the cultivar. In the later stages of ripening, differences in fruit totAsA-AsA concentrations of the two cultivars can be explained by differences in the rate of AsA recycling activities. Analysis of the expression of AsA metabolic genes showed that only the expression of one orthologue of GDP-L-galactose phosphorylase (SlGGP1, and of two monodehydroascorbate reductases (SlMDHAR1 and SlMDHAR3 correlated with the changes in fruit totAsA-AsA concentrations during fruit ripening in ‘Ailsa Craig’, and that only the expression of SlGGP1 was linked to the high AsA concentrations found in red ripe ‘Santorini’ fruits. Conclusions Results indicate that ‘Ailsa Craig’ and ‘Santorini’ use complementary mechanisms to maintain the fruit AsA pool. In the low-AsA cultivar (‘Ailsa Craig’, alternative routes of AsA biosynthesis may supplement biosynthesis via L-galactose, while in the high-AsA cultivar (‘Santorini’, enhanced AsA recycling activities appear to be responsible for AsA accumulation in the later stages of ripening. Gene expression studies indicate that expression of SlGGP1 and two orthologues of SlMDHAR are closely correlated with totAsA-AsA concentrations during ripening and are potentially good candidates for marker development for breeding and selection.

  4. Graphene ceramic composite as a new kind of surface-renewable electrode: application to the electroanalysis of ascorbic acid

    International Nuclear Information System (INIS)

    This study introduces a new surface-renewable electrode based on a sol–gel derived graphene ceramic composite. The electrode was prepared by dispersing graphene nanosheets into a solution of the sol–gel precursors containing methyl triethoxysilane in methanol and hydrochloric acid. During hydrolysis of methyl triethoxysilane, the graphene nanosheets are trapped in the gel. After moulding and drying the composite, it can be used as a surface-renewable electrode to which we refer as a graphene ceramic composite electrode (GCCE). Cyclic voltammograms of the hexacyanoferrate(II/III) model redox system at the GCCE were compared to those obtained with a conventional carbon ceramic electrode and showed a highly improved electron transfer rate at the GCCE. The electrocatalytic oxidation of ascorbic acid as a model analyte was then studied at working potential of 50 mV and over the 3–84 ?M concentration range. It revealed a sensitivity of 6.06 ?A ?M?1 cm?2 and a detection limit of 0.82 ?M. The GCCE was successfully applied to the determination of ascorbic acid in orange juice and urine samples. Advantages such as good mechanical and chemical stability, ease of fabrication, and reproducible preparation make the GCCE a potentially useful and widely applicable renewable electrode for use in routine analysis. (author)

  5. Understanding biocatalyst inhibition by carboxylic acids

    Directory of Open Access Journals (Sweden)

    LauraRJarboe

    2013-09-01

    Full Text Available Carboxylic acids are an attractive biorenewable chemical in terms of their flexibility and usage as precursors for a variety of industrial chemicals. It has been demonstrated that such carboxylic acids can be fermentatively produced using engineered microbes, such as Escherichia coli and Saccharomyces cerevisiae. However, like many other attractive biorenewable fuels and chemicals, carboxylic acids become inhibitory to these microbes at concentrations below the desired yield and titer. In fact, their potency as microbial inhibitors is highlighted by the fact that many of these carboxylic acids are routinely used as food preservatives. This review highlights the current knowledge regarding the impact that saturated, straight-chain carboxylic acids, such as hexanoic, octanoic, decanoic and lauric acids can have on E. coli and S. cerevisiae, with the goal of identifying metabolic engineering strategies to increase robustness. Key effects of these carboxylic acids include damage to the cell membrane and a decrease of the microbial internal pH. Certain changes in cell membrane properties, such as composition, fluidity, integrity and hydrophobicity, and intracellular pH are often associated with increased tolerance. The availability of appropriate exporters, such as Pdr12, can also increase tolerance. The effect on metabolic processes, such as maintaining appropriate respiratory function, regulation of Lrp activity and inhibition of production of key metabolites such as methionine, are also considered. Understanding the mechanisms of biocatalyst inhibition by these desirable products can aid in the engineering of robust strains with improved industrial performance.

  6. Studies of effect of heterocyclic dyes in photogalvanic cells for solar energy conversion and storage: NaLS-ascorbic acid system

    Indian Academy of Sciences (India)

    K R Genwa; Anju Chouhan

    2004-11-01

    The photogalvanic effect has been studied in three systems using photogalvanic cells and NaLS-ascorbic acid-azur A, NaLS-ascorbic acid-azur B, NaLS-ascorbic acid-azur C systems. The photopotential and photocurrent generated by these systems are 770.0, 971.0, 623.0 mV and 160.0, 185.0, 145.0 A respectively. The effects of different parameters on the electrical outputs of the cell have been observed and current-voltage characteristics of the cell studied, and a mechanism has been proposed for the generation of photocurrent in photogalvanic cells. The conversion efficiencies for azur A, azur B and azur C are 0.5461, 0.9646 and 0.4567% and storage capacity 110, 135 and 95 min respectively.

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. Effect of gamma irradiation in presence of ascorbic acid on microbial composition and TBARS concentration of ground beef coated with an edible active coating

    Energy Technology Data Exchange (ETDEWEB)

    Lacroix, M. E-mail: monique.lacroix@inrs-iaf.uquebec.ca; Ouattara, B.; Saucier, L.; Giroux, M.; Smoragiewicz, W

    2004-10-01

    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.

  12. Effect of gamma irradiation in presence of ascorbic acid on microbial composition and TBARS concentration of ground beef coated with an edible active coating

    Science.gov (United States)

    Lacroix, M.; Ouattara, B.; Saucier, L.; Giroux, M.; Smoragiewicz, W.

    2004-09-01

    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°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.

  13. Determination by HPLC of ascorbic acid and tocopherols in fruits / Determinação de ácido ascórbico e tocoferóis em frutas por CLAE

    Directory of Open Access Journals (Sweden)

    Rui Carlos Zambiazi

    2010-07-01

    Full Text Available The fruits and vegetables are recommended for human feeding due to the richness of antioxidant compounds. The bioactive compounds from the diet, such as vitamins C and E are important to reduce the speed of initiation or prevent the spread of free radicals. The objective of the work was to evaluate the ascorbic acid and tocopherol content of selections of Pitanga (Eugenia uniflora L., butiá (Butiá capitata, blackberry (Rubus spp, blueberry (Vaccium Reade ashei, loquat (Eribrotia japônica, jambolan (Eugenia jambolana, purple araçá (Psidium rufum, physalis (Physalis peruviana, pear (Pyrus communis and peaches (Prunus persica. The fruits were from 2006/2007/2008 harvest, which were obtained in Pelotas (RS region. The tocopherol analyses were performed according Rodrigues-Amaya (1999, and ascorbic acid according Vinci, Botre e Ruggieri (1995. The tocopherol and ascorbic acid identification and quantification was performed by high-efficiency liquid chromatography system (HPLC, using a fluorescent detector for tocopherol (excitation of 290 nm and emission of 330 nm and a UV-Visible (254 nm for ascorbic acid. The blackberry cv. Tupy showed the highest tocopherols content (8,251 ?g.g-1 fruit when compared with the other fruit content. The tocopherol was not found in pears and peaches of cv. Sensação and cv. Granada. The ascorbic acid content ranged from 9,291 mg.g-1 fruit for the physalis to 0,013 mg.g-1 fruit for the jambolan. It was concluded that the fruits are good sources of bioactive compounds.As frutas e as hortaliças são recomendadas na alimentação humana pela riqueza em compostos nutritivos e também pela presença de compostos que apresentam efeito antioxidante. Os compostos bioativos adquiridos através da dieta, como a vitamina C e a vitamina E, além do aspecto nutritivo, são importantes para reduzir a velocidade de iniciação ou prevenir a propagação de radicais livres. O objetivo deste estudo foi avaliar os teores de ácido ascórbico e de tocoferóis, de seleções de pitanga (Eugenia uniflora L., butiá (Butiá capitata, amora-preta (Rubus spp, mirtilo (Vaccium ashei Reade, nêspera (Eribrotia japônica, jambolão (Eugenia jambolana, araçá roxo (Psidium rufum, physalis (Physalis peruviana, pêra (Pyrus communis e pêssegos (Prunus persica. As frutas utilizadas foram das safras 2006/2007/2008, obtidas na região de Pelotas/RS. A análise dos tocoferóis foi realizada segundo Rodrigues-Amaya (1999, e do ácido ascórbico segundo Vinci, Botre e Ruggieri (1995. A identificação e quantificação dos tocoferóis e do ácido ascórbico foi realizada em um sistema de cromatografia liquída de alta eficiência (CLAE, utilizando detector de fluorescência para os tocoferóis (excitação em 290 nm e emissão em 330 nm e detector de UV-Visível para o ácido ascórbico (254 nm. A amora-preta cv. Tupy apresentou maior teor de tocoferóis (8,251 µg.g-1 de fruta quando comparado ao conteúdo das demais frutas. Na pêra e nos pêssegos cv. Sensação e cv. Granada não identificou-se a presença de tocoferóis. As concentrações de ácido ascórbico variaram de 9,291 mg.g-1 para o physalis à 0,013 mg.g-1 para o jambolão. Conclui-se que as frutas são boas fontes destes compostos bioativos.

  14. Iterative Saturation Mutagenesis of ?6 Subsite Residues in Cyclodextrin Glycosyltransferase from Paenibacillus macerans To Improve Maltodextrin Specificity for 2-O-d-Glucopyranosyl-l-Ascorbic Acid Synthesis

    OpenAIRE

    Han, Ruizhi; Long LIU; Shin, Hyun-dong; Chen, Rachel R.; Li, Jianghua; Du, Guocheng; Chen, Jian

    2013-01-01

    2-O-d-Glucopyranosyl-l-ascorbic acid (AA-2G), a stable l-ascorbic acid derivative, is usually synthesized by cyclodextrin glycosyltransferase (CGTase), which contains nine substrate-binding subsites (from +2 to ?7). In this study, iterative saturation mutagenesis (ISM) was performed on the ?6 subsite residues (Y167, G179, G180, and N193) in the CGTase from Paenibacillus macerans to improve its specificity for maltodextrin, which is a cheap and easily soluble glycosyl donor for AA-2G synthesis...

  15. Improvement on the thermal stability and activity of plant cytosolic ascorbate peroxidase 1 by tailing hyper-acidic fusion partners.

    Science.gov (United States)

    Zhang, Mengru; Gong, Ming; Yang, Yumei; Li, Xujuan; Wang, Haibo; Zou, Zhurong

    2015-04-01

    Cytosolic ascorbate peroxidase 1 (APX1) plays a crucial role in regulating the level of plant cellular reactive oxygen species and its thermolability is proposed to cause plant heat-susceptibility. Herein, several hyper-acidic fusion partners, such as the C-terminal peptide tails, were evaluated for their effects on the thermal stability and activity of APX1 from Jatropha curcas and Arabidopsis. The hyper-acidic fusion partners efficiently improved the thermostability and prevented thermal inactivation of APX1 in both plant species with an elevated heat tolerance of at least 2 °C. These hyper-acidified thermostable APX1 fusion variants are of considerable biotechnological potential and can provide a new route to enhance the heat tolerance of plant species especially of inherent thermo-sensitivity. PMID:25515798

  16. Poly (3-(3-Pyridyl) Acrylic Acid) Modified Glassy Carbon Electrode for Simultaneous Determination of Dopamine, Ascorbic Acid and Uric Acid

    International Nuclear Information System (INIS)

    Trans-3-(3-pyridyl) acrylic acid (PAA) was deposited on glassy carbon electrode (GCE) by electro polymerization in pH 7.0 phosphate buffer solution (PBS). The poly (3-(3-pyridyl) acrylic acid) (PPAA) film modified glassy carbon electrode shows an excellent electrochemical response for dopamine (DA), ascorbic acid (AA) and uric acid (UA). The cyclic voltammetry oxidation peaks for DA and AA, DA and UA, AA and UA are separated by 150 mV, 130 mV and 280 mV, respectively. This permits the simultaneous determination of AA, DA and UA. The interference of AA with the determination of DA could be eliminated because of the electrostatic interaction between DA cations and the negatively charged PPAA film at pH 7.0. The anodic peak currents of DA, AA and UA increase linearly with concentration in the range of 1-40 ?mol L-1, 10-400 ?mol L-1 and 1.6-80 ?mol L-1, respectively, with a correlation coefficient (r) always higher than 0.998. The detection limit is 0.06 ?mol L-1, 0.8 ?mol L-1 and 1.1 ?mol L-1 for DA, AA and UA, respectively

  17. ASCORBATE PEROXIDASE6 protects Arabidopsis desiccating and germinating seeds from stress and mediates cross talk between reactive oxygen species, abscisic acid, and auxin.

    Science.gov (United States)

    Chen, Changming; Letnik, Ilya; Hacham, Yael; Dobrev, Petre; Ben-Daniel, Bat-Hen; Vanková, Radomíra; Amir, Rachel; Miller, Gad

    2014-09-01

    A seed's ability to properly germinate largely depends on its oxidative poise. The level of reactive oxygen species (ROS) in Arabidopsis (Arabidopsis thaliana) is controlled by a large gene network, which includes the gene coding for the hydrogen peroxide-scavenging enzyme, cytosolic ASCORBATE PEROXIDASE6 (APX6), yet its specific function has remained unknown. In this study, we show that seeds lacking APX6 accumulate higher levels of ROS, exhibit increased oxidative damage, and display reduced germination on soil under control conditions and that these effects are further exacerbated under osmotic, salt, or heat stress. In addition, ripening APX6-deficient seeds exposed to heat stress displayed reduced germination vigor. This, together with the increased abundance of APX6 during late stages of maturation, indicates that APX6 activity is critical for the maturation-drying phase. Metabolic profiling revealed an altered activity of the tricarboxylic acid cycle, changes in amino acid levels, and elevated metabolism of abscisic acid (ABA) and auxin in drying apx6 mutant seeds. Further germination assays showed an impaired response of the apx6 mutants to ABA and to indole-3-acetic acid. Relative suppression of abscisic acid insensitive3 (ABI3) and ABI5 expression, two of the major ABA signaling downstream components controlling dormancy, suggested that an alternative signaling route inhibiting germination was activated. Thus, our study uncovered a new role for APX6, in protecting mature desiccating and germinating seeds from excessive oxidative damage, and suggested that APX6 modulate the ROS signal cross talk with hormone signals to properly execute the germination program in Arabidopsis. PMID:25049361

  18. Highly selective electrochemical sensor for ascorbic acid based on a novel hybrid graphene-copper phthalocyanine-polyaniline nanocomposites

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • A novel preparation method for nanocomposites, with CuPc immobilized on graphene in PANI matrix. • The Gr/CuPc/PANI enhanced selectivity and sensitivity of detecting AA due to graphene. • The constructed AA sensor shows excellent performances. - Abstract: In this work, we designed a novel electrochemical sensing platform based on graphene (Gr)/copper(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (CuPc)/polyaniline(PANI) nanocomposites. The prepared composites were used to modify screen printed electrodes (SPE) for selective determination of ascorbic acid (AA) in presence of dopamine (DA) and uric acid (UA). Copper phthalocyanine was immobilized on graphene sheets by ?-? interaction by electrolytical exfoliation and resulting CuPc/graphene was embedded in a PANI matrix to prevent leakage of Gr/CuPc from electrodes. The Gr/CuPc/PANI nanocomposites were characterized by scanning electron microscopy (SEM), UV-vis spectroscopy, cyclic voltammetry (CV) and amperometry. The prepared modified electrode presents good electrocatalytic properties, fast response time, high stability and reproducibility. The performance of the sensor exhibited a linear range from 5 × 10?7 to 1.2 × 10?5 M with low a limit of detection of 6.3 × 10?8 M (S/N = 3) and the sensitivity of the sensor was found to be 24.46 ?A mM?1. Moreover, the nanocomposites show excellent selectivity and lower potential for the oxidation of ascorbic acid. The novel sensor successfully applied to determination of AA in real samples with satisfactory results. This can open up new opportunities for fast, simple and selective detection of AA and provide a promising platform for sensor or biosensor designs for AA detection

  19. Ficocianina, tocoferol e ácido ascórbico na prevenção da oxidação lipídica em charque / Phycocyanin, tocopherol and ascorbic acid in the prevention of lipid oxidation in jerked beef

    Scientific Electronic Library Online (English)

    Telma Elita, Bertolin; Ana Claudia Freitas, Margarites; Bruna, Giacomelli; Andréia, Fruetti; Camila, Horts; Débora Marli de Freitas, Teixeira.

    2011-12-01

    Full Text Available Este estudo objetivou avaliar a prevenção da oxidação lipídica em charque através do uso de substâncias antioxidantes naturais e do antioxidante sintético butil hidroxitolueno (BHT). Utilizou-se bovino da raça Holandesa e o corte ponta de agulha para a elaboração das peças de charque. Os tratamentos [...] foram: Controle (sem adição de antioxidante), Tocoferol (adição de 0,03 %), Ficocianina (adição de 0,5 %), BHT (adição de 0,01 %), Tocoferol e Ácido ascórbico (adição de 0,03 % de cada) e cada tratamento foi composto por 5 mantas de charque. Os percentuais de antioxidantes foram adicionados com base no teor de lipídios da matéria-prima. Após o período de elaboração do charque, tempo zero, as mantas foram armazenadas em temperatura ambiente de 25 °C por 60 dias. Amostras representativas foram retiradas para a análise da oxidação lipídica através de índice de peróxidos (IP) e de índice de substâncias reativas ao ácido 2-tiobarbitúrico (TBARS). Os antioxidantes utilizados atenuaram a oxidação lipídica do charque e, dentre os antioxidantes naturais testados, a ficocianina apresentou a maior inibição da formação de peróxidos. O antioxidante ?-tocoferol apresentou melhor eficiência quando utilizado sinergicamente com o ácido ascórbico. Os resultados de TBARS indicaram que o BHT apresentou maior inibição e, dentre os naturais testados, a mistura de ácido ascórbico com tocoferol foi a mais eficiente. A utilização de antioxidantes naturais pode se tornar uma alternativa no retardamento da oxidação lipídica em charque e produtos similares. Abstract in english This study aimed to evaluate the prevention of lipid oxidation in jerked beef through the use of natural antioxidant substances and the synthetic antioxidant BHT. It was used spare ribs from Holstein cattle to elaborate the jerked beef pieces. The treatments were: Control (no addition of antioxidant [...] ), Tocopherol (addition of 0,03 %), Phycocyanin (addition of 0,5 %), BHT (addition of 0,01 %), Tocopherol and Ascorbic acid (addition of 0,03 % of each one), and each treatment had five slabs of jerked beef. The percentages of antioxidants added were according to the lipid content of the raw material. After preparation, zero time, the slabs were stored for 60 days at room temperature, 25 °C. Representative samples were taken for the analysis of lipid oxidation by way of the peroxide value (PV) and 2-thiobarbituric acid reactive substances (TBARS). The antioxidants attenuated the lipid oxidation of jerked beef and, among the natural antioxidants which were tested, Phycocyanin showed the highest inhibition of peroxide formation. The antioxidant ?-tocopherol presented a better efficiency when used synergistically with ascorbic acid. The TBARS results indicated that BHT showed the highest inhibition and, among the natural antioxidants tested, the mixture of ascorbic acid with tocopherol was more efficient. The use of natural antioxidants may become an alternative in delaying lipid oxidation in jerked beef and similar products.

  20. Ficocianina, tocoferol e ácido ascórbico na prevenção da oxidação lipídica em charque Phycocyanin, tocopherol and ascorbic acid in the prevention of lipid oxidation in jerked beef

    Directory of Open Access Journals (Sweden)

    Telma Elita Bertolin

    2011-12-01

    Full Text Available Este estudo objetivou avaliar a prevenção da oxidação lipídica em charque através do uso de substâncias antioxidantes naturais e do antioxidante sintético butil hidroxitolueno (BHT. Utilizou-se bovino da raça Holandesa e o corte ponta de agulha para a elaboração das peças de charque. Os tratamentos foram: Controle (sem adição de antioxidante, Tocoferol (adição de 0,03 %, Ficocianina (adição de 0,5 %, BHT (adição de 0,01 %, Tocoferol e Ácido ascórbico (adição de 0,03 % de cada e cada tratamento foi composto por 5 mantas de charque. Os percentuais de antioxidantes foram adicionados com base no teor de lipídios da matéria-prima. Após o período de elaboração do charque, tempo zero, as mantas foram armazenadas em temperatura ambiente de 25 °C por 60 dias. Amostras representativas foram retiradas para a análise da oxidação lipídica através de índice de peróxidos (IP e de índice de substâncias reativas ao ácido 2-tiobarbitúrico (TBARS. Os antioxidantes utilizados atenuaram a oxidação lipídica do charque e, dentre os antioxidantes naturais testados, a ficocianina apresentou a maior inibição da formação de peróxidos. O antioxidante ?-tocoferol apresentou melhor eficiência quando utilizado sinergicamente com o ácido ascórbico. Os resultados de TBARS indicaram que o BHT apresentou maior inibição e, dentre os naturais testados, a mistura de ácido ascórbico com tocoferol foi a mais eficiente. A utilização de antioxidantes naturais pode se tornar uma alternativa no retardamento da oxidação lipídica em charque e produtos similares.This study aimed to evaluate the prevention of lipid oxidation in jerked beef through the use of natural antioxidant substances and the synthetic antioxidant BHT. It was used spare ribs from Holstein cattle to elaborate the jerked beef pieces. The treatments were: Control (no addition of antioxidant, Tocopherol (addition of 0,03 %, Phycocyanin (addition of 0,5 %, BHT (addition of 0,01 %, Tocopherol and Ascorbic acid (addition of 0,03 % of each one, and each treatment had five slabs of jerked beef. The percentages of antioxidants added were according to the lipid content of the raw material. After preparation, zero time, the slabs were stored for 60 days at room temperature, 25 °C. Representative samples were taken for the analysis of lipid oxidation by way of the peroxide value (PV and 2-thiobarbituric acid reactive substances (TBARS. The antioxidants attenuated the lipid oxidation of jerked beef and, among the natural antioxidants which were tested, Phycocyanin showed the highest inhibition of peroxide formation. The antioxidant ?-tocopherol presented a better efficiency when used synergistically with ascorbic acid. The TBARS results indicated that BHT showed the highest inhibition and, among the natural antioxidants tested, the mixture of ascorbic acid with tocopherol was more efficient. The use of natural antioxidants may become an alternative in delaying lipid oxidation in jerked beef and similar products.

  1. Differential in vitro effects of homoarginine on oxidative stress in plasma, erythrocytes, kidney and liver of rats in the absence and in the presence ?-tocopherol, ascorbic acid or L-NAME.

    Science.gov (United States)

    Sasso, Simone; Dalmedico, Leticia; Magro, Débora Delwing-Dal; Pereira, Eduardo Manoel; Wyse, Angela T S; de Lima, Daniela Delwing-

    2015-09-01

    In the present study, we evaluated the in vitro effects of homoarginine (hArg) at 1, 10 and 20 µM on thiobarbituric acid-reactive substances (TBA-RS), total sulfhydryl content and on the activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in plasma, erythrocytes, kidney and liver of rats (60 days old). We also investigated the influence of the antioxidants (each at 1 mM) ?-tocopherol and ascorbic acid, as well as of the nitric oxide synthase inhibitor N (G)-nitro-L-arginine methyl ester (L-NAME) at 1 mM, on the effects elicited by hArg on the parameters tested. In plasma, hArg at concentrations of 10 and 20 ?M decreased moderately the total sulfhydryl content. At 20 µM, hArg enhanced moderately TBA-RS in the plasma. In plasma, the effects of hArg (20 µM) on TBA-RS and total thiol content were abolished by ?-tocopherol, ascorbic acid and L-NAME. At all concentrations tested, hArg did not exert any effect on CAT, SOD or GSH-Px activity in the erythrocytes. In the kidney, hArg exerted effects only at 20 µM and in a different manner: TBA-RS levels increased and total thiol content and CAT activity decreased, while SOD and GSH-Px activity increased. In the renal medulla, ?-tocopherol and ascorbic acid but not L-NAME abolished the effects of hArg (20 µM) on TBA-RS, while all agents inhibited the hArg-induced increase in SOD activity. In the renal cortex, ?-tocopherol, ascorbic acid and L-NAME abolished the effects of hArg (20 µM) on the total sulfhydryl content and GSH-Px activity, but L-NAME did not reverse the inhibitory effects of hArg on CAT activity. In the liver, no effects of hArg were observed of all biomarkers measured. At the pathologically high concentration of 20 µM, as it may occur in plasma in hyperargininemia, hArg may enhance lipid peroxidation and thiol oxidation and inhibit CAT activity, but may increase SOD and GSH-Px activity predominantly in the kidney. PMID:25894889

  2. Susceptibility of Propionibacterium acnes isolated from patients with acne vulgaris to zinc ascorbate and antibiotics

    Directory of Open Access Journals (Sweden)

    Iinuma K

    2011-10-01

    Full Text Available Katsuhiro Iinuma1, Norihisa Noguchi2, Hidemasa Nakaminami2, Masanori Sasatsu2, Setsuko Nishijima3, Isami Tsuboi1 1BML General Laboratory, Matoba, Kawagoe, Saitama, 2Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, 3Department of Dermatology, Nishijima Skin Clinic, Osaka, Japan Purpose: The in vitro antimicrobial activity of ascorbic acid derivatives against Propionibacterium acnes was tested either alone or in combination with a variety of antimicrobial agents, and their fractional inhibitory concentration index was determined using checkerboard tests. The antimicrobial effectiveness of zinc ascorbate in the treatment of acne vulgaris, either alone or in combination with antibiotics such as clindamycin that are commonly used in Japan for the treatment of acne vulgaris, was therefore examined. Materials and methods: The antimicrobial susceptibility of 41 strains of clindamycin-sensitive and/or clindamycin-resistant P. acnes isolated from acne vulgaris patients was tested, in comparison with a type strain of P. acnes. Results: Zinc ascorbate showed antimicrobial activity against a type strain of P. acnes and its concentration (0.064% was sufficiently lower than the normal dose (5% of other ascorbic acid derivatives. Combinations of zinc ascorbate with clindamycin, erythromycin, and chloramphenicol showed an additive effect, and zinc ascorbate alone effectively inhibited the growth of all P. acnes including clindamycin-resistant strains. Conclusion: The results provide novel evidence that the combination of zinc ascorbate and clindamycin is effective for acne vulgaris treatment. Keywords: antimicrobial susceptibility, ascorbic acid derivatives, combination therapy, checkerboard test

  3. Cognitive deficits and decreased locomotor activity induced by single-walled carbon nanotubes and neuroprotective effects of ascorbic acid

    Directory of Open Access Journals (Sweden)

    Liu X

    2014-02-01

    Full Text Available Xudong Liu,1,* Yuchao Zhang,1,* Jinquan Li,1 Dong Wang,1 Yang Wu,1 Yan Li,2 Zhisong Lu,3 Samuel CT Yu,4 Rui Li,1 Xu Yang1 1Laboratory of Environmental Biomedicine, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan, People's Republic of China; 2Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Hong Kong Special Administrative Region; 3Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing, People's Republic of China; 4Division of Environment, Hong Kong University of Science and Technology, Hong Kong Special Administrative Region *These authors contributed equally to this work Abstract: Single-walled carbon nanotubes (SWCNTs have shown increasing promise in the field of biomedicine, especially in applications related to the nervous system. However, there are limited studies available on the neurotoxicity of SWCNTs used in vivo. In this study, neurobehavioral changes caused by SWCNTs in mice and oxidative stress were investigated. The results of ethological analysis (Morris water maze and open-field test, brain histopathological examination, and assessments of oxidative stress (reactive oxygen species [ROS], malondialdehyde [MDA], and glutathione [GSH], inflammation (nuclear factor ?B, tumor necrosis factor a, interleukin-1?, and apoptosis (cysteine-aspartic acid protease 3 in brains showed that 6.25 and 12.50 mg/kg/day SWCNTs in mice could induce cognitive deficits and decreased locomotor activity, brain histopathological alterations, and increased levels of oxidative stress, inflammation, and apoptosis in mouse brains; however, 3.125 mg/kg/day SWCNTs had zero or minor adverse effects in mice, and these effects were blocked by concurrent administration of ascorbic acid. Down-regulation of oxidative stress, inflammation, and apoptosis were proposed to explain the neuroprotective effects of ascorbic acid. This work suggests SWCNTs could induce cognitive deficits and decreased locomotor activity, and provides a strategy to avoid the adverse effects. Keywords: behavioral changes, oxidative stress, inflammation, apoptosis

  4. Selective response of dopamine in the presence of ascorbic acid and uric acid at gold nanoparticles and multi-walled carbon nanotubes grafted with ethylene diamine tetraacetic acid modified electrode

    OpenAIRE

    Yun-fei Long; Yun-long Zeng; Xiao-fang Li; Xian-yong Yu; Hao-wen Huang; Bao-gang Lin; Chun-xiang Li; Zhong-hua Su; Ya-jing Wang; Ge Tian; Chun-ran Tang

    2009-01-01

    By grafting with ethylene diamine tetraacetic acid (EDTA), novel multi-walled carbon nanotube nano-composites (EDTA-MWCNTs) have been successfully prepared. The integration of gold nanoparticles (AuNPs) and novel functionalized matrix shows very promising applications in the fabrication of biosensors for sensitive detection of dopamine in the presence of ascorbic acid and uric acid with the combination of the charge repelling property of carboxylic anion and the electrocatalytic effect of EDT...

  5. Bioactivity-guided isolation of the active compounds from Rosa nutkana and quantitative analysis of ascorbic acid by HPLC.

    Science.gov (United States)

    Jovel, Eduardo M; Zhou, Xi Ling; Ming, Dong Sheng; Wahbe, Tanya R; Towers, G H Neil

    2007-09-01

    Rosa nutkana Presl. (Rosaceae) is distributed abundantly throughout central and southern areas of British Columbia, Canada. Aboriginal people in the Pacific Northwest have traditionally used R. nutkana as a food, medicine, and source of cultural material. The methanolic extract of the fruits of R. nutkana was previously found to have inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA). In our study, bioactivity-guided fractionation of the methanol extract from R. nutkana led to the isolation of the following 10 compounds: (i) tormentic acid, (ii) euscaphic acid, (iii) ursolic acid, (iv) maslinic acid, (v) quercetin, (vi) catechin gallate, (vii) quercetin-3-O-glucoside, (viii) 1,2,3,4,6-penta-O-galloyl-beta-D-glucoside, (ix) L-ascorbic acid (vitamin C), and (x) 1,6-digalloyl-beta-D-glucoside. Structures were elucidated by ultraviolet, infrared, mass spectrometry, and nuclear magnetic resonance data, as well as by comparison with those of the literature. The compounds quercetin, catechin gallate, quercetin-3-O-glucoside, 1,2,3,4,6-penta-O-galloyl-beta-D-glucoside, and 1,6-digalloyl-beta-D-glucoside exhibited weak antibacterial activity against MRSA. Our research demonstrates the value of traditional knowledge held by Aboriginal people in the Pacific Northwest with respect to uses of R. nutkana. Some described uses in the ethnobotanical literature correspond to activities observed under laboratory conditions. Further work on British Columbia Rosa spp. may contribute to identifying other potential therapeutic uses. PMID:18066132

  6. Contenido de osmoprotectores, ácido ascórbico y ascorbato peroxidasa en hojas de frijol sometidas a estrés por sequía / Osmoprotectants content, ascorbic acid and ascorbate peroxidase on bean leaves under drought stress

    Scientific Electronic Library Online (English)

    Teresa Susana, Herrera Flores; Joaquín, Ortíz Cereceres; Adriana, Delgado Alvarado; Jorge Alberto, Acosta Galleros.

    2014-08-01

    Full Text Available La acumulación de osmoprotectores en plantas que se encuentran en condiciones de estrés por sequía, le permiten contrarrestar el efecto negativo que le provoca dichas condición ambiental. En el presente trabajo se estudió la respuesta bioquímica de plantas de frijol con base en la acumulación de car [...] bohidratos solubles, almidón, ácido ascórbico, así como la actividad de la enzima ascorbato peroxidasa, en las hojas simples y en las dos primeras hojas trifolioladas de la variedad resistente, Pinto Villa, y la susceptible a sequía Bayo Madero, ambas de raza Durango. Las plantas de ambas variedades se sometieron a tres tratamientos de humedad, riego, sequía y riego de recuperación. Con respecto a Bayo Madero, Pinto Villa mostró una mayor respuesta de tolerancia al estrés de humedad relacionada con: altas concentraciones de prolina, de ácido ascórbico y mayor actividad de la enzima ascorbato peroxidasa, ésta última en el tratamiento de sequía. En relación a la cantidad de carbohidratos solubles, Bayo Madero fue estadísticamente superior (p Abstract in english The accumulation of osmoprotectants in plants that are under stress from drought, allow you to offset the negative effect that causes these environmental conditions. In this study the biochemical response of bean plants based on the accumulation of soluble carbohydrates, starch, ascorbic acid, and t [...] he activity of ascorbate peroxidase enzyme, simple leaves and the first two leaves trifoliolate of studied resistant variety, Pinto Villa, and susceptible to drought Bayo Madero, both of Durango race. Plants from two varieties were subjected to three moisture treatments, irrigation and irrigation drought recovery. Regarding Bayo Madero, Pinto Villa showed increased stress tolerance response related humidity: high concentrations of proline, ascorbic acid, and increased activity of the peroxidase enzyme ascorbate, the latter in the drying treatment. In relation to the amount of soluble carbohydrates, Bayo Madero was statistically superior (p

  7. Electrochemical Deposition and Characterization of Poly(3,4-ethylene dioxythiophene), Poly(aniline) and their Copolymer onto Glassy Carbon Electrodes for Potential Use in Ascorbic Acid Oxidation

    Scientific Electronic Library Online (English)

    G.M., El-Enany; M.A., Ghanem; M.A. Abd, El-Ghaffar.

    Full Text Available Poly(3,4-ethylene dioxythiophene) (PEDOT), poly(aniline) (PANI) and their copolymer (PEDOT-PANI) were electrodeposited onto a glassy carbon electrode. The electrodeposition was performed using cyclic voltammetry from acidic solution containing appropriate monomer concentrations and sodium dodecyl su [...] lphate (SDS) as a wetting agent. The resulting polymer films were characterised using cyclic voltammetry in acidic and neutral phosphate buffer solutions and IR spectroscopy. The specific capacitance of the PEDOT-PANI co-polymer reaches up to 260 F g?1 and had good stability during cycling in mineral acid solution. IR spectroscopy confirms the formation of PEDOT-PANI copolymer. The polymers showed an electrochemical activity towards ascorbic acid oxidation. The oxidation current was linearly dependant up to 20 mM ascorbic acid concentration and the PEDOT activity was much higher than that for PANI and PEDOT-PANI copolymer.

  8. Development of HPLC and UV spectrophotometric methods for the determination of ascorbic acid using hydroxypropyl-?-cyclodextrin and triethanolamine as photostabilizing agents

    International Nuclear Information System (INIS)

    In this study, the effect of complex formation with triethanolamine (TEA) alone and in combination with hydroxypropyl-?-cyclodextrin (HP-?-CD) on the photostability of ascorbic acid was evaluated for exposure to artificial and diffuse daylight. The first-order rate constants for the photodegradation reactions were determined. The data obtained showed that these complexes strongly reduced the photodegradation process with an 11- and 35-fold increase in the photostability of ascorbic acid, depending of the ligand concentration and the irradiation source. The multicomponent complex gave a significantly better stabilization for exposure to light than TEA alone. Due to the fact that the complexation extended the exposure of ascorbic acid to light (without molecular changes), UV spectrophotometric and reversed phase high performance liquid chromatographic (HPLC) methods were developed for the quantitative determination of the vitamin in pure form and in pharmaceutical preparations. These methods were statistically validated, all the validation parameters were found to be within the acceptance range. These results demonstrate that the proposed methods are suitable for the quality control of ascorbic acid, providing simple, rapid, precise, accurate and convenient approaches for routine analysis of bulk drug and pharmaceutical formulations.

  9. Efficacy of morning-only 4 liter sulfa free polyethylene glycol vs 2 liter polyethylene glycol with ascorbic acid for afternoon colonoscopy

    OpenAIRE

    Rivas, John M; Perez, Alejandro; Hernandez, Marlow; Schneider, Alison; Castro, Fernando J

    2014-01-01

    AIM: To compare the bowel cleansing efficacy of same day ingestion of 4-L sulfa-free polyethylene glycol (4-L SF-PEG) vs 2-L polyethylene glycol solution with ascorbic acid (2-L PEG + Asc) in patients undergoing afternoon colonoscopy.

  10. Quantification and histochemical localization of ascorbic acid in 'Delicious', 'Golden Delicious', and 'Fuji' apple fruit during on-tree development and cold storage

    Science.gov (United States)

    Apple fruit are subject to multiple stressors during pre- and post-harvest development. Stress-induced reactive oxygen species (ROS) can be detrimental to the fruit, and ascorbic acid (AsA) is involved in many of the antioxidant pathways that detoxify ROS. An inclusive study to characterize AsA dy...

  11. Collard, mustard and turnip greens: Effects of varieties and leaf position on concentrations of ascorbic acid, folate, B-carotene, lutein and phylloquinone

    Science.gov (United States)

    Leafy Brassica crops: collard (Brassica oleracea L.), mustard (B. juncea L.) and turnip (B. rapa) greens are important commercial and culinary vegetables; especially in the southern United States. However, almost no information on essential human-health vitamins [ascorbic acid (vit C), folate (vit...

  12. Study of anticlastogenic effect of ascorbic acid in relation to damage induced by photomutagenic action of 8-metoxypsoralen and ammonium molibdenate in human lymphocytes

    International Nuclear Information System (INIS)

    In experiments with cultured human lymphocytes anticlastogenic effect of ascorbic acid (AA) with respect to photomutagenic action of 8-methoxypsoralen (8-MOP) and ammonium molibdenate (Mo) was studied. It was found that AA effectively protected from mutagenic action of Mo. effective protection of cells from 8-MOP monoadducts and DNA interstrand links was also observed. 6 refs.; 2 tabs

  13. Quantitative trace analysis of L-ascorbic acid in human body fluids by on-line combination of capillary isotachophoresis and zone electrophoresis.

    Science.gov (United States)

    Procházková, A; Krivánková, L; Bocek, P

    1998-02-01

    On-line combination of capillary isotachophoresis and zone electrophoresis performed in two coupled capillaries (ITP-CZE) is used for the trace analysis of L-ascorbic acid in human serum, urine and stomach fluid. At the ITP stage, anionic sample components are separated into individual zones and macrocomponents are detected and driven out of the migration path. In the CZE stage, only a small segment of the sample zones containing L-ascorbic acid is analyzed. High sensitivity of this hyphenated method (limit of detection, 0.09-0.15 mg/L), low sample volume consumption (2 microL), and acceptable reproducibility of the results (relative standard deviation, 8%) in the concentration range 0.1-15 mg/L demonstrate that the method is applicable for the study of the relation between the content of L-ascorbic acid in body fluids and the state of health of a person, in which lower amounts of L-ascorbic acid than the normal levels (i.e., 5.1-15.1 mg/L in human serum and 12.5-26.8 mg/L in urine) are expected. Possible interferences of other components of the body fluids are excluded by good correlation of the results obtained by the ITP-CZE method and a routine colorimetric method. PMID:9548295

  14. Stimulative Effects of Ascorbic Acid, Thiamin or Pyridoxine on Vicia faba Growth and Some Related Metabolic Activities

    OpenAIRE

    A. M. Hamada; E. M. Khulaef

    2000-01-01

    Soaking of bean seeds in 100 ppm ascorbic acid, thiamin or pyridoxine induced a stimulation effect on germination. Also, soaking of seeds or spraying of bean seedlings (25 day old) with 100 ppm of each of these vitamins, stimulated fresh and dry weight, biosynthesis of photosynthetic pigment fractions and net photosynthetic rate. However, these treatments did not induce a considerable change in dark respiration.

  15. Spectrophotometric determination of titanium with ascorbic acid in aluminium alloys and other materials. Determinacion espectrofotometrica de titanio con acido ascorbico en aleaciones de base aluminio y otros materiales

    Energy Technology Data Exchange (ETDEWEB)

    Bosch Serrat, F. (Departamento de Quimica Analitica. Facultad de Qauimica. Valencia (Spain))

    1994-01-01

    A spectrophotometric determination of titanium with ascorbic acid in aluminium alloys and bauxite is described. The proposed procedures permit to determine levels of titanium down to 5.10 ''3% with a good accuracy and precision. (Author) 13 refs.

  16. Development of HPLC and UV spectrophotometric methods for the determination of ascorbic acid using hydroxypropyl-{beta}-cyclodextrin and triethanolamine as photostabilizing agents

    Energy Technology Data Exchange (ETDEWEB)

    Garnero, Claudia [Departamento de Farmacia, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Longhi, Marcela, E-mail: mrlcor@fcq.unc.edu.ar [Departamento de Farmacia, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2010-02-05

    In this study, the effect of complex formation with triethanolamine (TEA) alone and in combination with hydroxypropyl-{beta}-cyclodextrin (HP-{beta}-CD) on the photostability of ascorbic acid was evaluated for exposure to artificial and diffuse daylight. The first-order rate constants for the photodegradation reactions were determined. The data obtained showed that these complexes strongly reduced the photodegradation process with an 11- and 35-fold increase in the photostability of ascorbic acid, depending of the ligand concentration and the irradiation source. The multicomponent complex gave a significantly better stabilization for exposure to light than TEA alone. Due to the fact that the complexation extended the exposure of ascorbic acid to light (without molecular changes), UV spectrophotometric and reversed phase high performance liquid chromatographic (HPLC) methods were developed for the quantitative determination of the vitamin in pure form and in pharmaceutical preparations. These methods were statistically validated, all the validation parameters were found to be within the acceptance range. These results demonstrate that the proposed methods are suitable for the quality control of ascorbic acid, providing simple, rapid, precise, accurate and convenient approaches for routine analysis of bulk drug and pharmaceutical formulations.

  17. A gold electrode with a flower-like gold nanostructure for simultaneous determination of dopamine and ascorbic acid

    International Nuclear Information System (INIS)

    We have developed a facile method for the preparation of a gold electrode modified with a flower-like gold nanostructure using potentiostatic electrodeposition. Its formation, morphology, and electrochemical properties were studied by scanning electron microscopy and cyclic voltammetry. The resulting nanostructures possess rough and enlarged surface areas and enable fast electron transfer in the selective and sensitive detection of ascorbic acid (AA) and dopamine (DA) in phosphate-buffered saline without disturbance by common interferents. The differential pulse voltammetry anodic peak currents at approximately ?0.03 V and 0.16 V are strongly enhanced in the presence of AA and DA, respectively. The electrode responds linearly to AA in the concentration range from 60 ?M to 500 ?M, with a limit of detection at 10 ?M. The respective data for DA are 1 ?M to 150 ?M, and the limit of detection is 0.2 ?M. (author)

  18. Ascorbic acid for the healing of skin wounds in rats Ácido ascórbico na cicatrização de feridas cutâneas em ratos

    Directory of Open Access Journals (Sweden)

    CC. Lima

    2009-11-01

    Full Text Available 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 weighing 270 ± 30 g were used. After thionembutal anesthesia, 15 mm transversal incisions were made in the animals' cervical backs. They were divided into two groups: Control Group (CG, n = 12 - skin wound cleaned with water and soap daily; Treated Group (TG, n = 12 - skin wound cleaned daily and treated with ascorbic acid cream (10%. Samples of skin were collected on the 3rd, 7th and 14th days. The sections were stained with hematoxylin-eosin and picrosirius red for morphologic analysis. The images were obtained and analysed by a Digital Analyser System. RESULTS: The ascorbic acid acted on every stage of the healing process. It reduced the number of macrophages, increased the proliferation of fibroblasts and new vessels, and stimulated the synthesis of thicker and more organized collagen fibres in the wounds when compared to CG. CONCLUSION: Ascorbic acid was shown to have anti-inflammatory and healing effects, guaranteeing a suiTable environment and conditions for faster skin repair.FUNDAMENTOS: A cicatrização é um processo complexo que envolve eventos celulares e bioquímicos. Vários medicamentos têm sido empregados na tentativa de abreviar a cicatrização e evitar danos estéticos. OBJETIVO: verificar o efeito tópico do ácido ascórbico no processo de cicatrização de feridas cutâneas de ratos através da verificação do número de macrófagos, neovasos e fibroblastos presentes no período experimental; e analisar a espessura e a organização das fibras colágenas no tecido lesado. MÉTODOS: Foram utilizados Rattus norvegicus, machos, pesando 270 ± 30 g. Foi realizada incisão transversal na pele da região dorso-cervical de 15 mm de comprimento, após anestesia com Thionembutal. Os animais foram divididos em 2 grupos: grupo controle (GC, n = 12, feridas higienizadas diariamente com água e sabão; grupo tratado (GT, n = 12, feridas higienizadas e tratadas com creme de ácido ascórbico (10%. Os fragmentos para análise histológica foram coletados no 3º, 7º e 14º dia, e as lâminas coradas com hematoxilina-eosina e picrosírius red para análise morfológica. As imagens foram capturadas e analisadas por um sistema digitalizador. RESULTADOS: O ácido ascórbico atuou em todas as etapas da cicatrização, diminuindo o número de macrófagos, aumentando a proliferação dos fibroblastos e neovasos, e favorecendo a deposição de fibras colágenas mais espessas e organizadas nas feridas. CONCLUSÃO: O ácido ascórbico mostrou ter efeito antiinflamatório e cicatrizante, promovendo ambiente e condições favoráveis para a reparação tecidual, o que abreviou o tempo da cicatrização.

  19. Ascorbic acid for the healing of skin wounds in rats / Ácido ascórbico na cicatrização de feridas cutâneas em ratos

    Scientific Electronic Library Online (English)

    CC., Lima; APC., Pereira; JRF., Silva; LS., Oliveira; MCC., Resck; CO., Grechi; MTCP., Bernardes; FMP., Olímpio; AMM., Santos; EK., Incerpi; JAD., Garcia.

    2009-11-01

    Full Text Available FUNDAMENTOS: A cicatrização é um processo complexo que envolve eventos celulares e bioquímicos. Vários medicamentos têm sido empregados na tentativa de abreviar a cicatrização e evitar danos estéticos. OBJETIVO: verificar o efeito tópico do ácido ascórbico no processo de cicatrização de feridas cutâ [...] neas de ratos através da verificação do número de macrófagos, neovasos e fibroblastos presentes no período experimental; e analisar a espessura e a organização das fibras colágenas no tecido lesado. MÉTODOS: Foram utilizados Rattus norvegicus, machos, pesando 270 ± 30 g. Foi realizada incisão transversal na pele da região dorso-cervical de 15 mm de comprimento, após anestesia com Thionembutal. Os animais foram divididos em 2 grupos: grupo controle (GC, n = 12), feridas higienizadas diariamente com água e sabão; grupo tratado (GT, n = 12), feridas higienizadas e tratadas com creme de ácido ascórbico (10%). Os fragmentos para análise histológica foram coletados no 3º, 7º e 14º dia, e as lâminas coradas com hematoxilina-eosina e picrosírius red para análise morfológica. As imagens foram capturadas e analisadas por um sistema digitalizador. RESULTADOS: O ácido ascórbico atuou em todas as etapas da cicatrização, diminuindo o número de macrófagos, aumentando a proliferação dos fibroblastos e neovasos, e favorecendo a deposição de fibras colágenas mais espessas e organizadas nas feridas. CONCLUSÃO: O ácido ascórbico mostrou ter efeito antiinflamatório e cicatrizante, promovendo ambiente e condições favoráveis para a reparação tecidual, o que abreviou o tempo da cicatrização. Abstract in english 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 ma [...] crophages, 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 weighing 270 ± 30 g were used. After thionembutal anesthesia, 15 mm transversal incisions were made in the animals' cervical backs. They were divided into two groups: Control Group (CG, n = 12) - skin wound cleaned with water and soap daily; Treated Group (TG, n = 12) - skin wound cleaned daily and treated with ascorbic acid cream (10%). Samples of skin were collected on the 3rd, 7th and 14th days. The sections were stained with hematoxylin-eosin and picrosirius red for morphologic analysis. The images were obtained and analysed by a Digital Analyser System. RESULTS: The ascorbic acid acted on every stage of the healing process. It reduced the number of macrophages, increased the proliferation of fibroblasts and new vessels, and stimulated the synthesis of thicker and more organized collagen fibres in the wounds when compared to CG. CONCLUSION: Ascorbic acid was shown to have anti-inflammatory and healing effects, guaranteeing a suiTable environment and conditions for faster skin repair.

  20. Nitrate, ascorbic acid, mineral and antioxidant activities of Cosmos caudatus in response to organic and mineral-based fertilizer rates.

    Science.gov (United States)

    Hassan, Siti Aishah; Mijin, Salumiah; Yusoff, Umi Kalsom; Ding, Phebe; Wahab, Puteri Edaroyati Megat

    2012-01-01

    The source and quantity of nutrients available to plants can affect the quality of leafy herbs. A study was conducted to compare quality of Cosmos caudatus in response to rates of organic and mineral-based fertilizers. Organic based fertilizer GOBI (8% N:8% P?O?:8% K?O) and inorganic fertilizer (15% N, 15% P?O?, 15% K?O) were evaluated based on N element rates at 0, 30, 60, 90, 120 kg h?¹. Application of organic based fertilizer reduced nitrate, improved vitamin C, antioxidant activity as well as nitrogen and calcium nutrients content. Antioxidant activity and chlorophyll content were significantly higher with increased fertilizer application. Fertilization appeared to enhance vitamin C content, however for the maximum ascorbic acid content, regardless of fertilizer sources, plants did not require high amounts of fertilizer. PMID:22743588

  1. Uso do ácido ascórbico no controle do escurecimento do pericarpo de lichia Use of ascorbic acid in the control of browning in the pericarp of lychees

    Directory of Open Access Journals (Sweden)

    Danieele Fabíola Pereira da Silva

    2010-06-01

    Full Text Available Um dos maiores problemas na pós-colheita da lichia é o escurecimento do pericarpo, o qual tem sido atribuído à degradação da antocianina. O objetivo do trabalho foi avaliar o efeito de diferentes doses de ácido ascórbico na prevenção do escurecimento do pericarpo e na manutenção da qualidade pós-colheita de lichia. Frutos de lichieira 'Bengal' com o pericarpo completamente vermelho foram imersos em solução com diferentes doses de ácido ascórbico (0; 5; 10; 15 e 30 mM, por 5 minutos. Após secagem à temperatura ambiente, foram acondicionados em bandejas de poliestireno, armazenados em câmara fria a 5 ± 1,2°C e 90 ± 5% de UR e avaliados a cada 4 dias, durante 12 dias. Observou-se que a perda de massa fresca foi maior nos frutos não tratados com ácido ascórbico. Independentemente da dose, o ácido ascórbico teve pouco efeito na retenção da cor vermelha do pericarpo de lichia. A atividade das enzimas polifenoloxidase e peroxidase no pericarpo foi maior com as menores doses de ácido ascórbico (0; 5 e 10 mM, entretanto observou-se escurecimento a partir do quarto dia no pericarpo dos frutos tratados com este ácido. O ácido ascórbico também não foi eficiente na manutenção da qualidade interna dos frutos.One of the biggest problems in postharvest of lychees is the pericarp browning, which has been attributed to anthocyanins degradation. The purpose of this work was to evaluate the effect of different doses of ascorbic acid to prevent pericarp browning and on the maintenance of postharvest quality of lychees. Fruits of 'Bengal' lychee with completely red pericarp were immersed in solution with different doses of ascorbic acid (0, 5, 10, 15 and 30 mM for 5 minutes. After dried, the fruits were packed in polystyrene trays, stored in cold chamber at 5 ± 1,2°C e 90 ± 5% de RH and evaluated every other 4 days for 12 days. It was observed that the loss of fresh weight was higher in non-treated with ascorbic acid fruits. Independently of the dose, the ascorbic acid had little effect on the retention of the red color of the lychee pericarp. The polyphenoloxidase and peroxidase activities in the lychee pericarp was increased with lower doses of ascorbic acid (0, 5 and 10 mM, however, there was pericarp browning after the fourth day in the fruits of all treatments in ascorbic acid. Ascorbic acid was not efficient in maintaining the internal quality of fruit.

  2. Uso do ácido ascórbico no controle do escurecimento do pericarpo de lichia / Use of ascorbic acid in the control of browning in the pericarp of lychees

    Scientific Electronic Library Online (English)

    Danieele Fabíola Pereira da, Silva; Elaine Cristina, Cabrini; Robson Ribeiro, Alves; Luiz Carlos Chamhum, Salomão.

    2010-06-01

    Full Text Available Um dos maiores problemas na pós-colheita da lichia é o escurecimento do pericarpo, o qual tem sido atribuído à degradação da antocianina. O objetivo do trabalho foi avaliar o efeito de diferentes doses de ácido ascórbico na prevenção do escurecimento do pericarpo e na manutenção da qualidade pós-col [...] heita de lichia. Frutos de lichieira 'Bengal' com o pericarpo completamente vermelho foram imersos em solução com diferentes doses de ácido ascórbico (0; 5; 10; 15 e 30 mM), por 5 minutos. Após secagem à temperatura ambiente, foram acondicionados em bandejas de poliestireno, armazenados em câmara fria a 5 ± 1,2°C e 90 ± 5% de UR e avaliados a cada 4 dias, durante 12 dias. Observou-se que a perda de massa fresca foi maior nos frutos não tratados com ácido ascórbico. Independentemente da dose, o ácido ascórbico teve pouco efeito na retenção da cor vermelha do pericarpo de lichia. A atividade das enzimas polifenoloxidase e peroxidase no pericarpo foi maior com as menores doses de ácido ascórbico (0; 5 e 10 mM), entretanto observou-se escurecimento a partir do quarto dia no pericarpo dos frutos tratados com este ácido. O ácido ascórbico também não foi eficiente na manutenção da qualidade interna dos frutos. Abstract in english One of the biggest problems in postharvest of lychees is the pericarp browning, which has been attributed to anthocyanins degradation. The purpose of this work was to evaluate the effect of different doses of ascorbic acid to prevent pericarp browning and on the maintenance of postharvest quality of [...] lychees. Fruits of 'Bengal' lychee with completely red pericarp were immersed in solution with different doses of ascorbic acid (0, 5, 10, 15 and 30 mM) for 5 minutes. After dried, the fruits were packed in polystyrene trays, stored in cold chamber at 5 ± 1,2°C e 90 ± 5% de RH and evaluated every other 4 days for 12 days. It was observed that the loss of fresh weight was higher in non-treated with ascorbic acid fruits. Independently of the dose, the ascorbic acid had little effect on the retention of the red color of the lychee pericarp. The polyphenoloxidase and peroxidase activities in the lychee pericarp was increased with lower doses of ascorbic acid (0, 5 and 10 mM), however, there was pericarp browning after the fourth day in the fruits of all treatments in ascorbic acid. Ascorbic acid was not efficient in maintaining the internal quality of fruit.

  3. Electrocatalytic oxidation and voltammetric determination of ciprofloxacin employing poly(alizarin red)/graphene composite film in the presence of ascorbic acid, uric acid and dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xin; Wei, Youli; Ding, Yaping, E-mail: wdingyp@sina.com

    2014-07-04

    Graphical abstract: An electrochemical sensor based on PAR/EGR/GCE via a cooperation of the potentiostatic technique and cyclic voltammetry was first fabricated for the determination of CPFX with satisfied detecting result of real samples. - Highlights: • PAR/EGR composite film was prepared for the first time. • The sensor can be applied to determinate CPFX in the presence of AA, UA and DA. • The sensor indicated the feasibility in drug samples and biological media. - Abstract: A glassy carbon electrode modified with poly(alizarin red)/electrodeposited graphene (PAR/EGR) composite film was prepared and applied to detect ciprofloxacin (CPFX) in the presence of ascorbic, uric acid and dopamine. The morphology and interface property of PAR/EGR films were examined by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The electrocatalytic oxidation of CPFX on AR/EGR was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The linearity ranged from 4 × 10{sup ?8} to 1.2 × 10{sup ?4} M with a detection limit (S/N = 3) of 0.01 ?M. The modified electrode could be applied to the individual determination of CPFX as well as the simultaneous determination of CPFX, ascorbic acid, uric acid and dopamine. This method proved to be a simple, selective and rapid way to determine CPFX in pharmaceutical preparation and biological media.

  4. Electrocatalytic oxidation and voltammetric determination of ciprofloxacin employing poly(alizarin red)/graphene composite film in the presence of ascorbic acid, uric acid and dopamine

    International Nuclear Information System (INIS)

    Graphical abstract: An electrochemical sensor based on PAR/EGR/GCE via a cooperation of the potentiostatic technique and cyclic voltammetry was first fabricated for the determination of CPFX with satisfied detecting result of real samples. - Highlights: • PAR/EGR composite film was prepared for the first time. • The sensor can be applied to determinate CPFX in the presence of AA, UA and DA. • The sensor indicated the feasibility in drug samples and biological media. - Abstract: A glassy carbon electrode modified with poly(alizarin red)/electrodeposited graphene (PAR/EGR) composite film was prepared and applied to detect ciprofloxacin (CPFX) in the presence of ascorbic, uric acid and dopamine. The morphology and interface property of PAR/EGR films were examined by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The electrocatalytic oxidation of CPFX on AR/EGR was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The linearity ranged from 4 × 10?8 to 1.2 × 10?4 M with a detection limit (S/N = 3) of 0.01 ?M. The modified electrode could be applied to the individual determination of CPFX as well as the simultaneous determination of CPFX, ascorbic acid, uric acid and dopamine. This method proved to be a simple, selective and rapid way to determine CPFX in pharmaceutical preparation and biological media

  5. Effects of L- and iso-ascorbic acid on meat protein hydrolyzing activity of four commercial plant and three microbial protease preparations.

    Science.gov (United States)

    Ha, Minh; Bekhit, Alaa El-Din; Carne, Alan

    2014-04-15

    The present study investigated the effects of both l- and iso-ascorbic acid (AA) on the activity of four plant proteases (papain, bromelain, actinidin and zingibain) and three microbial proteases (Bacterial Protease G, Fungal 31,000 and Fungal 60,000) preparations using fluorescent-labelled casein, meat myofibrillar and connective tissue extracts to explore their effects on meat structure components upon treatment with individual proteases. While l-AA in the range 0.8-3.2mM inhibited the activity of papain, bromelain and zingibain, iso-AA acted as an inhibitor of papain but as an activator of zingibain and had no significant effect on bromelain. Both AA isoforms acted as an activator of the actinidin protease and the concentration of AA isoforms appeared to affect the level of activation of the protease. The effect of the two AA isoforms on collagen and myofibrillar protein hydrolyzing activity varied depending on the concentration of the two AA isoforms. The results indicate the ability to up and down regulate the activity of the investigated proteases by using an appropriate concentration of the AA isoform. PMID:24295669

  6. Polarographic study of the Cu(II)/Cu(I) system in the presence of 1-ascorbic acid and 0,1 M ClK

    International Nuclear Information System (INIS)

    While studying the catalytic effect of Cu?2 ions on the oxidation process of 1-ascorbic acid, it has been observed that, in a 0,1 M solution of K1 at a pH 6 to 7, the above acid gives rise in the presence of Cu?2 ions to a polarographic wave of half-wave potential of -0,41 V (vs. S.C.E.). (Author) 14 refs

  7. Phosphonoacetic Acid Inhibition of Frog Virus 3 Replication

    OpenAIRE

    Elliott, R M; Bateson, A.; Kelly, D. C.

    1980-01-01

    Phosphonoacetic acid at concentrations above 200 ?g/ml inhibited the replication of frog virus 3 in BHK cells. The inhibition of viral DNA replication observed in these cells was reversible and correlated with the inhibition of the virus-induced DNA polymerase activity in an in vitro assay. The synthesis of frog virus 3-induced late or ? polypeptides was also inhibited by phosphonoacetic acid, although the early (? and ?) polypeptides were unaffected.

  8. 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

    Directory of Open Access Journals (Sweden)

    Christiane de Queiroz Pereira

    2008-12-01

    Full Text Available 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 opened. The ascorbic acid content presented a great variability among the samples analyzed ranging from 37.3 to 46.3 mg.100 mL-1 in ready-to-drink juices and from 75.7 to 152 mg.100 mL-1 in concentrated juices. The storage of commercial cashew apple juices for 48 hours at 4 °C resulted in ascorbic acid losses of up to 8.8% for concentrated and 6.4% for ready-to-drink juices. The other parameters remained stable during storage. The results of this study point to the importance of considering ascorbic acid losses in commercial cashew apple juices which occurs after opening but before the expiration date expires.Sucos de caju industrializados são amplamente aceitos no mercado brasileiro. O caju contém alto teor de ácido ascórbico, importante nutriente para o ser humano. O teor deste nutriente pode ser afetado pelo processamento e pelas condições de estocagem dos alimentos. Foram analisadas amostras de sucos industrializados de caju, prontos para o consumo e concentrados. O teor de ácido ascórbico, a acidez total titulável, o teor de sólidos solúveis totais e o pH dos sucos foram determinados durante estocagem a 4 °C, após abertura das embalagens. Houve grande variabilidade no teor de ácido ascórbico entre as amostras, 37,3 a 46,3 mg.100 mL-1 nos sucos prontos para o consumo e 75,7 a 152 mg.100 mL-1 nos sucos concentrados. A estocagem dos sucos por 48 horas a 4 °C resultou em redução do teor de ácido ascórbico em até 8,8% para os concentrados e em até 6,4% para os prontos para o consumo. Os demais parâmetros analisados permaneceram estáveis durante a estocagem. Os resultados deste estudo demonstram a importância de se considerar a redução do teor de ácido ascórbico que ocorre em sucos industrializados de caju durante o período de validade, após a abertura da embalagem.

  9. 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

    Scientific Electronic Library Online (English)

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

    2008-12-01

    Full Text Available Sucos de caju industrializados são amplamente aceitos no mercado brasileiro. O caju contém alto teor de ácido ascórbico, importante nutriente para o ser humano. O teor deste nutriente pode ser afetado pelo processamento e pelas condições de estocagem dos alimentos. Foram analisadas amostras de sucos [...] industrializados de caju, prontos para o consumo e concentrados. O teor de ácido ascórbico, a acidez total titulável, o teor de sólidos solúveis totais e o pH dos sucos foram determinados durante estocagem a 4 °C, após abertura das embalagens. Houve grande variabilidade no teor de ácido ascórbico entre as amostras, 37,3 a 46,3 mg.100 mL-1 nos sucos prontos para o consumo e 75,7 a 152 mg.100 mL-1 nos sucos concentrados. A estocagem dos sucos por 48 horas a 4 °C resultou em redução do teor de ácido ascórbico em até 8,8% para os concentrados e em até 6,4% para os prontos para o consumo. Os demais parâmetros analisados permaneceram estáveis durante a estocagem. Os resultados deste estudo demonstram a importância de se considerar a redução do teor de ácido ascórbico que ocorre em sucos industrializados de caju durante o período de validade, após a abertura da embalagem. Abstract in english 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 a [...] nd 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 opened. The ascorbic acid content presented a great variability among the samples analyzed ranging from 37.3 to 46.3 mg.100 mL-1 in ready-to-drink juices and from 75.7 to 152 mg.100 mL-1 in concentrated juices. The storage of commercial cashew apple juices for 48 hours at 4 °C resulted in ascorbic acid losses of up to 8.8% for concentrated and 6.4% for ready-to-drink juices. The other parameters remained stable during storage. The results of this study point to the importance of considering ascorbic acid losses in commercial cashew apple juices which occurs after opening but before the expiration date expires.

  10. A thin poly(acridine orange) film containing reduced graphene oxide for voltammetric simultaneous sensing of ascorbic acid and uric acid

    International Nuclear Information System (INIS)

    We have fabricated, in a single step, carbon ceramic electrodes modified with a poly(acridine orange) film containing reduced graphene oxide. They display electrocatalytic activity to ascorbic acid (AA) and uric acid (UA) at pH 4.5. The anodic peak potentials of AA and UA are separated by 276 mV so that they can be well resolved in cyclic voltammetry. UA and AA were simultaneously determined in a mixture at working potentials of 170 and 400 mV, respectively. Under optimized conditions, the calibration curves for AA and UA cover the 0.8–5,000 ?M and 0.6–900 ?M concentration range, respectively, while detection limits are 0.3 ?M and 0.2 ?M. The electrode was applied to determine AA and UA in urine samples. (author)

  11. Exogenous salicylic acid improves photosynthesis and growth through increase in ascorbate-glutathione metabolism and S assimilation in mustard under salt stress

    Science.gov (United States)

    Nazar, Rahat; Umar, Shahid; Khan, Nafees A.

    2015-01-01

    Ascorbate (AsA)–glutathione (GSH) cycle metabolism has been regarded as the most important defense mechanism for the resistance of plants under stress. In this study the influence of salicylic acid (SA) was studied on ascorbate-glutathione pathway, S-assimilation, photosynthesis and growth of mustard (Brassica juncea L.) plants subjected to 100 mM NaCl. Treatment of SA (0.5 mM) alleviated the negative effects of salt stress and improved photosynthesis and growth through increase in enzymes of ascorbate-glutathione pathway which suggest that SA may participate in the redox balance under salt stress. The increase in leaf sulfur content through higher activity of ATP sulfurylase (ATPS) and serine acetyl transferase (SAT) by SA application was associated with the increased accumulation of glutathione (GSH) and lower levels of oxidative stress. These effects of SA were substantiated by the findings that application of SA-analog, 2,6, dichloro-isonicotinic acid (INA) and 1 mM GSH treatment produced similar results on rubisco, photosynthesis and growth of plants establishing that SA application alleviates the salt-induced decrease in photosynthesis mainly through inducing the enzyme activity of ascorbate-glutathione pathway and increased GSH production. Thus, SA/GSH could be a promising tool for alleviation of salt stress in mustard plants. PMID:25730495

  12. The non-oxidative degradation of ascorbic acid at physiological conditions.

    Science.gov (United States)

    Simpson, G L; Ortwerth, B J

    2000-04-15

    The degradation of L-ascorbate (AsA) and its primary oxidation products, L-dehydroascorbate (DHA) and 2,3-L-diketogulonate (2, 3-DKG) were studied under physiological conditions. Analysis determined that L-erythrulose (ERU) and oxalate were the primary degradation products of ASA regardless of which compound was used as the starting material. The identification of ERU was determined by proton decoupled (13)C-nuclear magnetic resonance spectroscopy, and was quantified by high performance liquid chromatography, and enzymatic analysis. The molar yield of ERU from 2,3-DKG at pH 7.0 37 degrees C and limiting O(2)97%. This novel ketose product of AsA degradation, was additionally qualitatively identified by gas-liquid chromatography, and by thin layer chromatography. ERU is an extremely reactive ketose, which rapidly glycates and crosslinks proteins, and therefore may mediate the AsA-dependent modification of protein (ascorbylation) seen in vitro, and also proposed to occur in vivo in human lens during diabetic and age-onset cataract formation. PMID:10727845

  13. Interferência do acido ascórbico na determinação de açúcares redutores pelo método de Lane e Eynon Ascorbic acid interference in the determination of reducing and total sugars by Lane and Eynon method

    Directory of Open Access Journals (Sweden)

    José Torquato de Queiroz Tavares

    2010-01-01

    Full Text Available Two studies, both set up as completely randomized design, in a 5x5 and 7x5 factorial schemes, evaluated the interference of 5 and 7 ascorbic acid concentrations and 5 glucose or 5 sucrose concentrations, respectively, on the determination of total and reducing sugars by Lane and Eynon method. The ascorbic acid reducing power (AARP over the Fehling liquor interfered in the results of total and reducing sugars. On average the AARP was equivalent to 74.83 and 69.71% of the reducing power of glucose and of hydrolyzed sucrose, respectively. The ascorbic acid was stable in all study conditions.

  14. 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

    OpenAIRE

    EFSA Panel on Additives and Products or Substances used in Animal Feed

    2013-01-01

    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 c...

  15. Direct electrodeposition of gold nanotube arrays of rough and porous wall by cyclic voltammetry and its applications of simultaneous determination of ascorbic acid and uric acid

    International Nuclear Information System (INIS)

    Gold nanotube arrays of rough and porous wall has been synthesized by direct electrodeposition with cyclic voltammetry utilizing anodic aluminum oxide template (AAO) and polycarbonate membrane (PC) during short time (only 3 min and 2 min, respectively). The mechanism of the direct electrodeposition of gold nanotube arrays by cyclic voltammetry (CV) has been discussed. The morphological characterizations of the gold nanotube arrays have been investigated by scanning electron microscopy (SEM). A simultaneous determination of ascorbic acid (AA) and uric acid (UA) by differential pulse voltammetry (DPV) was constructed by attaching gold nanotube arrays (using AAO) onto the surface of a glassy carbon electrode (GCE). The electrochemical behavior of AA and UA at this modified electrode has been studied by CV and differential pulse voltammetry (DPV). The sensor offers an excellent response for AA and UA and the linear response range for AA and UA were 1.02 × 10?7–5.23 × 10?4 mol L?1 and 1.43 × 10?7–4.64 × 10?4 mol L?1, the detection limits were 1.12 × 10?8 mol L?1 and 2.24 × 10?8 mol L?1, respectively. This sensor shows good regeneration, stability and selectivity and has been used for the determination of AA and UA in real human urine and serum samples with satisfied results. - Graphical abstract: The schematic diagram of formation of Au nanotube arrays (a) and the stepwise procedure of the sensor (b). Highlights: ? Gold nanotubes array has been synthesized by cyclic voltammetry. ? The mechanism of deposition of gold nanotube has been discussed. ? A determination of ascorbic acid and uric acid was constructed by gold array. ? A satisfied determination of samples can be obtained by this sensor.

  16. Use of green rooibos (Aspalathus linearis) extract and water-soluble nanomicelles of green rooibos extract encapsulated with ascorbic acid for enhanced aspalathin content in ready-to-drink iced teas.

    Science.gov (United States)

    Joubert, Elizabeth; Viljoen, Melvi; De Beer, Dalene; Malherbe, Christiaan J; Brand, D Jacobus; Manley, Marena

    2010-10-27

    Heat-induced changes in aspalathin, iso-orientin, and orientin content of ready-to-drink (RTD) green rooibos iced tea formulations were investigated. An organic-solvent-based aspalathin-enriched extract prepared from green rooibos was used "as-is" or encapsulated with ascorbic acid in a water-soluble nanomicelle-based carrier system. The common iced tea ingredients, ascorbic acid, and/or citric acid were added to the iced tea containing green rooibos extract. Only citric acid was added to the iced tea containing the nanomicelles. Heat treatments consisted of pasteurization (93 °C/5 min and 93 °C/30 min), normal-temperature sterilization (NTS; 121 °C/15 min), and high-temperature sterilization (HTS; 135 °C/4 min). Pasteurization had little or no effect on the flavonoid content. NTS and HTS induced significant losses in the flavonoids. The addition of citric and ascorbic acids improved the stability of the flavonoids, but encapsulation of green rooibos extract with ascorbic acid in nanomicelles did not offer additional stability. The only benefit of using the water-soluble nanomicelles was the improved clarity of the RTD product. Iso-orientin and orientin contents were substantially less affected than aspalathin by the heat treatments, partially because of conversion of aspalathin to these flavones, which countered losses. 5-Hydroxymethylfurfural (HMF), a known dehydration product of hexoses under mild acidic conditions and also a degradation product of ascorbic acid, was observed in formulations containing citric and/or ascorbic acids. PMID:20923193

  17. Melatonin, minocycline and ascorbic acid reduce oxidative stress and viral titers and increase survival rate in experimental Venezuelan equine encephalitis.

    Science.gov (United States)

    Valero, Nereida; Mosquera, Jesús; Alcocer, Sirley; Bonilla, Ernesto; Salazar, Jenny; Álvarez-Mon, Melchor

    2015-10-01

    Venezuelan equine encephalitis (VEE) virus causes an acute central nervous system infection in human and animals. Melatonin (MLT), minocycline (MIN) and ascorbic acid (AA) have been shown to have antiviral activities in experimental infections; however, the mechanisms involved are poorly studied. Therefore, the aim of this study was to determine the effects of those compounds on the viral titers, NO production and lipid peroxidation in the brain of mice and neuroblastoma cultures infected by VEE virus. Infected mouse (10 LD50) were treated with MLT (500?g/kg bw), MIN (50mg/kg bw) or AA (50mg/kg bw). Infected neuroblastoma cultures (MOI: 1); MLT: 0.5, 1, 5mM, MIN: 0.1, 0.2, 2?M or AA: 25, 50, 75?M. Brains were obtained at days 1, 3 and 5. In addition, survival rate of infected treated mice was also analyzed. Viral replication was determined by the plaque formation technique. NO and lipid peroxidation were measured by Griess? reaction and thiobarbituric acid assay respectively. Increased viral replication, NO production and lipid peroxidation were observed in both, infected brain and neuroblastoma cell cultures compared with uninfected controls. Those effects were diminished by the studied treatments. In addition, increased survival rate (50%) in treated infected animals compared with untreated infected mice (0%) was found. MLT, MIN and AA have an antiviral effect involving their anti-oxidant properties, and suggesting a potential use of these compounds for human VEE virus infection. PMID:26168898

  18. Zeolite A functionalized with copper nanoparticles and graphene oxide for simultaneous electrochemical determination of dopamine and ascorbic acid

    International Nuclear Information System (INIS)

    Graphical abstract: A novel Cu-zeolite A/graphene-modified glassy carbon electrode was applied in the simultaneous electrochemical determination of dopamine (DA) and ascorbic acid (AA). The potential difference between the two oxidation peaks of DA and AA were over 200 mV. The electrocatalytic oxidation currents of DA were linearly related to the corresponding concentration in the range of 1.0 × 10?7–1.9 × 10?5 M. Highlights: ? Cu nanoparticles doped-zeolite A/graphene (CuZEA/RGO) modified electrode was prepared. ? The composites of CuZEA/RGO were prepared via reduction of Cu2+ functionalized zeolite A and graphene oxide in one pot. ? The modified electrode was presented for the simultaneous determination of DA and AA. ? The proposed electrode showed a higher electrocatalytic performance. - Abstract: A novel Cu-zeolite A/graphene modified glassy carbon electrode for the simultaneous electrochemical determination of dopamine (DA) and ascorbic acid (AA) has been described. The Cu-zeolite A/graphene composites were prepared using Cu2+ functionalized zeolite A and graphene oxide as the precursor, and subsequently reduced by chemical agents. The composites were characterized by X-ray diffraction, Fourier transform infrared spectra and scanning electron microscopy. Based on the Cu-zeolite A/graphene-modified electrode, the potential difference between the oxidation peaks of DA and AA was over 200 mV, which was adequate for the simultaneous electrochemical determination of DA and AA. Also the proposed Cu-zeolite/graphene-modified electrode showed higher electrocatalytic performance than zeolite/graphene electrode or graphene-modified electrode. The electrocatalytic oxidation currents of DA and AA were linearly related to the corresponding concentration in the range of 1.0 × 10?7–1.9 × 10?5 M for DA and 2.0 × 10?5–2.0 × 10?4 M for AA. Detection limits (S/N = 3) were estimated to be 4.1 × 10?8 M for DA and 1.1 × 10?5 M for AA, respectively.

  19. 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

    Scientific Electronic Library Online (English)

    Ana Paula S., Paim; Eloisa Ap. M., Kronka; Boaventura F., Reis; Mauro, Korn.

    1998-02-01

    Full Text Available [...] Abstract in english 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 QuickBa [...] sic 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 about 7% when compared with recommended method. Other profitable features such as a standard deviation of 1.5% (n = 7) and a throughput of 120 determinations per hour was also achieved.

  20. The effect of gamma radiation on the peroxides activity, colour and ascorbic acid content of papaya

    International Nuclear Information System (INIS)

    The activity of peroxidase enzyme increases during ripening with external colour used as a maturity index. An experiment indicated that 200 Krad dose level was most effective in inhibiting any increase in peroxidase activity when papaya was stored at room temperature. The doses of 25, 50 and 100 Krad level at least double the shelf life of fruit with 100 Krad was the most effective when kept in the cold. The development of yellow colour and synthesis of vitamin C is not effected. So, this preliminary study indicates that gamma radiation prolongs the shelf life of papaya when stored at cold or room temperature due to the inhibiting of the ripening process. It is also suggested that treatment of fungicides combined with gamma radiation might have an additive effect on shelf life

  1. Effect of gamma radiation on the peroxides activity, colour and ascorbic acid content of papaya

    Energy Technology Data Exchange (ETDEWEB)

    Asmah, R.; Nitisewojo, P. (National Univ. of Malaysia, Bangi, Selangor)

    1977-01-01

    The activity of peroxidase enzyme increases during ripening with external colour used as a maturity index. An experiment indicated that 200 Krad dose level was most effective in inhibiting any increase in peroxidase activity when papaya was stored at room temperature. The doses of 25, 50 and 100 Krad level at least double the shelf life of fruit with 100 Krad was the most effective when kept in the cold. The development of yellow colour and synthesis of vitamin C is not effected. So, this preliminary study indicates that gamma radiation prolongs the shelf life of papaya when stored at cold or room temperature due to the inhibiting of the ripening process. It is also suggested that treatment of fungicides combined with gamma radiation might have an additive effect on shelf life.

  2. Association between circulating ascorbic acid, ?-tocopherol, 25-hydroxyvitamin D, and plasma cytokine concentrations in young adults: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    García-Bailo Bibiana

    2012-11-01

    Full Text Available Abstract Background Inflammation and oxidative stress are associated with the development of numerous chronic diseases. Circulating ascorbic acid, ?-tocopherol, and 25-hydroxyvitamin D (25(OHD may help reduce concentrations of pro-inflammatory cytokines through their antioxidant and anti-inflammatory properties. These micronutrients may act synergistically, and they may have different anti-inflammatory effects, but previous studies have assessed the link between each of these micronutrients and inflammation in isolation without controlling for the other micronutrients. Our objective was to examine the association between circulating concentrations of ascorbic acid, ?-tocopherol, and 25(OH D and a panel of pro-inflammatory cytokines in an ethnically diverse population of young adults. Methods Participants (n?=?1,007 from the Toronto Nutrigenomics and Health study provided fasting blood samples for biomarker measurements and were subsequently categorized into tertiles for each micronutrient based on their circulating concentrations. We conducted Pearson’s correlation analyses across all micronutrients and cytokines. The associations between individual micronutrients and cytokines were examined using analysis of covariance with age, sex, waist circumference, ethnicity, physical activity, season of blood collection, total cholesterol, hormonal contraceptive use among women, and the other two micronutrients as covariates. Results We observed weak micronutrient-cytokine correlations, moderate correlations between certain cytokines, and strong correlations between specific cytokines, particularly interleukin 1- receptor antagonist (IL-1RA, interferon-? (IFN-?, and platelet-derived growth factor BB (PDGF-bb. After full covariate adjustment, circulating ?-tocopherol was inversely associated with IFN-? and regulated upon activation normal T-cell expressed and secreted (RANTES. We observed an unexpected positive association between ascorbic acid and IFN-?. 25(OHD was not associated with altered concentrations of any inflammatory biomarkers. Conclusions These findings suggest that ?-tocopherol, but not ascorbic acid or 25(OHD, is inversely associated with inflammation in healthy young adults.

  3. Orally Administrated Ascorbic Acid Suppresses Neuronal Damage and Modifies Expression of SVCT2 and GLUT1 in the Brain of Diabetic Rats with Cerebral Ischemia-Reperfusion

    OpenAIRE

    Naohiro Iwata; Mari Okazaki; Meiyan Xuan; Shinya Kamiuchi; Hirokazu Matsuzaki; Yasuhide Hibino

    2014-01-01

    Diabetes mellitus is known to exacerbate cerebral ischemic injury. In the present study, we investigated antiapoptotic and anti-inflammatory effects of oral supplementation of ascorbic acid (AA) on cerebral injury caused by middle cerebral artery occlusion and reperfusion (MCAO/Re) in rats with streptozotocin-induced diabetes. We also evaluated the effects of AA on expression of sodium-dependent vitamin C transporter 2 (SVCT2) and glucose transporter 1 (GLUT1) after MCAO/Re in the brain. The ...

  4. Determination of Dopamine in the Presence of Ascorbic Acid by Nafion and Single-Walled Carbon Nanotube Film Modified on Carbon Fiber Microelectrode

    OpenAIRE

    Haesang Jeong; Seungwon Jeon

    2008-01-01

    Carbon fiber microelectrode (CFME) modified by Nafion and single-walled carbon nanotubes (SWNTs) was studied by voltammetric methods in phosphate buffer saline (PBS) solution at pH 7.4. The Nafion-SWNTs/CFME modified microelectrode exhibited strongly enhanced voltammetric sensitivity and selectivity towards dopamine (DA) determination in the presence of ascorbic acid (AA). Nafion-SWNTs film accelerated the electron transfer reaction of DA, but Nafion film as a negatively charged polymer restr...

  5. Role of Glycinebetaine and Ascorbic Acid in the Alleviation of Salt-Stress Induced Micro-Morphological Damages in Sweet Pepper Seedlings

    OpenAIRE

    A.A. Arafa; M.A. Khafagy; M.F. El-Banna

    2007-01-01

    The effects of exogenously applied glycinebetaine or ascorbic acid (pre-soaking or pre-soaking plus spraying) on the salt-stress induced ultrastructural damages in sweet pepper seedlings were investigated. The seedlings grown in hydroponic culture containing nutrient solution for 4 weeks treated with NaCl at (0 and 6000 ppm). Salinity induced ultrastructural damages in leaf, the most notable changes were swelling of thylakoid membrane, disintegration of grana stacking and intergrana lamellae ...

  6. Ascorbic acid pre-treated quartz stimulates TNF-? release in RAW 264.7 murine macrophages through ROS production and membrane lipid peroxidation

    OpenAIRE

    Benvenuto Federica; Ferraris Chiara; Pozzolini Marina; Magnone Mirko; Scarfì Sonia; Benatti Umberto; Giovine Marco

    2009-01-01

    Abstract Background Inhalation of crystalline silica induces a pulmonary fibrotic degeneration called silicosis caused by the inability of alveolar macrophages to dissolve the crystalline structure of phagocytosed quartz particles. Ascorbic acid is capable of partially dissolving quartz crystals, leading to an increase of soluble silica concentration and to the generation of new radical sites on the quartz surface. The reaction is specific for the crystalline forms of silica. It has been alre...

  7. Study of a direct method for 99Tcm labeling of monoclonal antibody. Pt.2: The effect of ascorbic acid in the direct labeling

    International Nuclear Information System (INIS)

    The effects of ascorbic acid (AA) on the process of direct labeling of monoclonal antibody are investigated. Based on the comparison of the relevant experimental conditions, it is found that AA has a strong antioxidizing effect on reduced antibody and also a stabilizing effect on the labels. Monoclonal antibody fragments F(ab')2 are successfully labeled using the method. Biodistributions of the labels are measured in tumor bearing nude mice. Tumor localization in vitro is also achieved

  8. Annexin V assay-proven anti-apoptotic effect of ascorbic acid 2-glucoside after cold ischemia/reperfusion injury in rat liver transplantation.

    OpenAIRE

    Liu J; Yagi T; Sadamori H; Matsukawa H; Sun DS; Mitsuoka N; Yamamura M; Matsuoka J; Jin Z; Yamamoto I; Tanaka N

    2003-01-01

    Controversy exists over whether the predominant cell death of hepatocytes is due to apoptosis or necrosis after ischemia/reperfusion injury. In this study we investigated the predominant cell death of hepatocytes after cold ischemia/reperfusion injury using the Annexin V-based assay, and evaluated the anti-apoptotic effect of ascorbic acid 2-glucoside (AA-2G) added to the University of Wisconsin solution (UW solution) in rat liver transplantation. The retrieved liver was preserved in 4 UW sol...

  9. Influence of maturity at harvest, N fertiliser and postharvest storage on dry matter, ascorbic acid and B-carotene contents of vegetable amaranth

    OpenAIRE

    Onyango, C.; Harbinson, J.; J.K. Imungi; VAN KOOTEN, O.

    2011-01-01

    Vegetable amaranth is a leafy vegetable traditionally grown in sub-Saharan Africa and Asia where it is the most consumed traditional vegetable. It is considered to have high nutritional quality, containing relatively large amounts of vitamins A and C. We have assessed the influence of the maturity of the vegetable and soil nutrition on the visual and nutritional quality of amaranth. We found that leaf ascorbic acid content is strongly influenced by both maturity and soil nutrition, with leave...

  10. Responses of serum electrolytes of goats to twelve hours of road transportation during the hot-dry season in Nigeria, and the effect of pretreatment with ascorbic acid

    Scientific Electronic Library Online (English)

    J.O., Ayo; N.S., Minka; A.K.B., Sackey; A.B., Adelaiye.

    Full Text Available Twenty goats which served as the experimental group were administered ascorbic acid (AA) per os at a dosage rate of 100 mg/kg body mass, while 20 others served as controls and were given 10 ml each of sterile water. Forty minutes after the administration and loading, the goats were transported for 1 [...] 2 h. Handling and loading of the experimental and control groups of goats decreased (p

  11. Modification of elution efficiency of 99mTc from 99Mo/99mTc gel generators using ascorbic acid

    OpenAIRE

    Mohammad Reza Davarpanah; Sima Attar Nosrati; Hosseinali Khoshhosn

    2010-01-01

    Introduction: Newer applications of radiopharmaceuticals in nuclear medicine require pertechnetate of moderate to high radioactive concentration. Hence there is a need to develop simple procedures for the concentration of pertechnetate. In this paper the influence of the addition of ascorbic acid to the eluent saline solution on the 99mTc elution yield is examined. Methods: Molybdenum-99 produced by neutron activation of molybdenum [98Mo(n,?)99Mo] in the research reactor of Tehran w...

  12. The effect of combined treatment of alpha-tocopherol, ascorbic acid, and pyridoxine with NMDA blocker memantine on penicillin-induced epileptiform activity in rats

    OpenAIRE

    Duygu AYDIN; Yildirim, Mehmet; Mustafa AYYILDIZ; A?AR, Erdal

    2013-01-01

    To evaluate the effects of coadministration of vitamins alpha-tocopherol, ascorbic acid, and pyridoxine with memantine on a penicillin-induced experimental epilepsy model in rats so as to clarify the eventual interaction between these vitamins and the N-methyl-D-aspartate (NMDA) system. Materials and methods: The epileptic focus was produced by intracortical penicillin G potassium injection. The effects of intraperitoneal injections of memantine, memantine + alpha-tocopherol, memantine + asc...

  13. Performance traits and immune response of broiler chicks treated with zinc and ascorbic acid supplementation during cyclic heat stress

    Science.gov (United States)

    Chand, Naila; Naz, Shabana; Khan, Ajab; Khan, Sarzamin; Khan, Rifat Ullah

    2014-12-01

    This research was conducted to investigate the effect of supplementation of zinc (Zn) and ascorbic acid (AA) in heat-stressed broilers. A total of 160-day-old broiler chicks of approximately the same weight and appearance were divided into four treatment groups (control, T1, T2, and T3). Control group was fed a standard diet without any supplementation. T1 was supplemented with Zn at the rate of 60 mg/kg of feed, T2 was supplemented with 300 mg/kg of feed AA, and T3 was supplemented with combination of Zn and AA. From week 3 to 5, heat stress environment was provided at the rate of 12 h at 25 °C, 3 h at 25 to 34 °C, 6 h at 34 °C, and 3 h at 34 to 25 °C daily. The results revealed that feed intake, body weight and feed conversion ratio (FCR), and weight of thymus, spleen, and bursa of Fabricius improved significantly ( P disease (ND), infectious bursal disease (IBD), and infectious bronchitis (IB) increased significantly ( P stress.

  14. Guest-Host Complex Formed between Ascorbic Acid and ?-Cyclodextrin Immobilized on the Surface of an Electrode

    Directory of Open Access Journals (Sweden)

    María Teresa Ramírez-Silva

    2014-05-01

    Full Text Available This work deals with the formation of supramolecular complexes between ascorbic acid (AA, the guest, and ?-cyclodextrin (?-CD, the host, that was first potentiodynamically immobilized on the surface of a carbon paste electrode (CPE throughout the formation of a ?-CD-based conducting polymer (poly-?-CD. With the bare CPE and the ?-CD-modified CPE, an electrochemical study was performed to understand the effect of such surface modification on the electrochemical response of the AA. From this study it was shown that on the modified-CPE, the AA was surface-immobilized through formation of an inclusion complex with ?-CD, which provoked the adsorption of AA in such a way that this stage became the limiting step for the electrochemical oxidation of AA. Moreover, from the analysis of the experimental voltammetric plots recorded during AA oxidation on the CPE/poly-?-CD electrode surfaces, the Gibbs’ standard free energy of the inclusion complex formed by the oxidation product of AA and ?-CD has been determined for the first time, ?G0inclus = ?36.4 kJ/mol.

  15. How the multiple antioxidant properties of ascorbic acid affect lipid oxidation in oil-in-water emulsions.

    Science.gov (United States)

    Uluata, Sibel; McClements, D Julian; Decker, Eric A

    2015-02-18

    Lipid oxidation is a serious problem for oil-containing food products because it negatively affects shelf life and nutritional composition. An antioxidant strategy commonly employed to prevent or delay oxidation in foods is to remove oxygen from the closed food-packaging system. An alternative technique is use of an edible oxygen scavenger to remove oxygen within the food. Ascorbic acid (AA) is a particularly promising antioxidant because of its natural label and multiple antioxidative functions. In this study, AA was tested as an oxygen scavenger in buffer and an oil-in-water (O/W) emulsion. The effects of transition metals on the ability of AA to scavenge oxygen were determined. Headspace oxygen decrease less than 1% in the medium-chain triacylglycerol (MCT) O/W emulsion system (pH 3 and 7). AA was able to almost completely remove dissolved oxygen (DO) in a buffered solution. Transition metals (Fe(2+) and Cu(+)) significantly accelerated the degradation of AA; however, iron and copper only increased DO depletion rates, by 10.6-16.4% from day 1 to 7, compared to the control. AA (2.5-20 mM) decreased DO in a 1% O/W emulsion system 32.0-64.0% and delayed the formation of headspace hexanal in the emulsion from 7 to over 20 days. This research shows that, when AA is used in an O/W emulsion system, oxidation of the emulsion system can be delay by multiple mechanisms. PMID:25650525

  16. Assessment of thermal load on transported goats administered with ascorbic acid during the hot-dry conditions.

    Science.gov (United States)

    Minka, N S; Ayo, J O

    2012-03-01

    The major factor in the induction of physiological stress during road transportation of livestock is the complex fluctuations of the thermal transport microenvironment, encountered when animals are transported across different ecological zones. Recommended guidelines on optimum "on-board" conditions in which goats should be transported are lacking, and there are no acceptable ranges and limits for the thermal loads to which goats may be subjected during long-distance road transportation in hot-dry conditions. Panting score (PS), rectal temperature (RT), heart rate (HR) and respiratory rate (RR) were employed as reliable stress indices to assess the effects of different thermal loads, measured as temperature humidity index (THI), encountered in the vehicle during 12 h of road transportation of 40 goats, and to suggest the administration of 100 mg/kg body weight of ascorbic acid (AA) as an ameliorating agent. The results obtained showed that the PS, RT, HR and RR rose above normal reference values with increase in the THI and journey duration. The rise in PS value, which is a visual indicator of the severity of thermal load, was the most pronounced. The results suggest that values of THI in the vehicle up to 94.6 constitute no risk, while at of 100 it presents a moderate risk and above 100 may result in severe stress. The relationships between the thermal load and the physiological variables were positive and significant (P?factors due to road transportation in goats. PMID:21544699

  17. Highly sensitive and selective electrochemical determination of dopamine and ascorbic acid at Ag/Ag{sub 2}S modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chen-Yan [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Cai, Ying-Jie [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Yang, Chien-Hsin [Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan (China); Wu, Chen-Hao [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Wei, Yen [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Chemistry, Drexel University, Philadelphia, PA 19104 (United States); Wen, Ten-Chin, E-mail: tcwen@mail.ncku.edu.t [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Wang, Tzong-Liu; Shieh, Yeong-Tarng [Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan (China); Lin, Wen-Churng [Department of Environmental Engineering, Kun Shan University, Tainan 71016, Taiwan (China); Chen, Wen-Janq [Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan (China)

    2011-02-01

    A biosensor electrode possessing highly sensitive and selective determination of dopamine (DA) is fabricated. This electrode, a silver (Ag) thin film on indium-tin-oxide glass, is treated with a silver sulfide (Ag{sub 2}S) film using electrochemical deposition. Active Ag ion is easier to form on Ag{sub 2}S than on pristine Ag, which prefers to attract ascorbic acid (AA). The Ag{sub 2}S layer reduces the oxidation potential of AA due to the electrostatic interaction, which results in well-separation of mixed oxidation responses to both of DA and AA. Besides, the Ag{sub 2}S-modified electrode exhibits dramatic electrocatalytic effect on the oxidation of DA in the presence of AA. In 0.1 M phosphate buffer solution at pH {approx} 7.0, the differential pulse voltammetric peak intensity linearly correlates with DA concentration in two regions, viz. 1.0-10, and 10-100 {mu}M, with correlation coefficient of 0.998 and 0.995, respectively. The lowest concentration limit of 1.0 {mu}M DA can be detected. The interference of AA effectively diminishes in the mixed solution. These features make the Ag{sub 2}S significant for selective and sensitive measurement of DA in the presence of excess AA.

  18. Encapsulation artocarpanone and ascorbic acid in O/W microemulsions: Preparation, characterization, and antibrowning effects in apple juice.

    Science.gov (United States)

    Dong, Xue; Zhu, Qin; Dai, Yaqing; He, Jianfei; Pan, Hongyang; Chen, Jie; Zheng, Zong-Ping

    2016-02-01

    The aim of this study is to improve artocarpanone solubility by developing an O/W microemulsion with the evaluation of its antibrowning effects. The chemical and physical stabilities as well as antibrowning effects in apple juice were also evaluated. The formulation of artocarpanone microemulsion consisted of 4% w/w of ethyl butyrate, 10.67% w/w of Tween 80, 5.33% w/w of polyethylene glycol 400, and 80% w/w of water, with a maximum solubility of artocarpanone up to 10.54 ± 0.01 mg/mL, at least 3000-folds increase in solubility compared that in water. Encapsulating artocarpanone and ascorbic acid (VC) into microemulsion simultaneously decreased modest artocarpanone solubility whereas improving its stability in long-term storage. Blank, artocarpanone and artocarpanone-Vc-loaded microemulsions demonstrated steadily during accelerated and long-term storage. Artocarpanone-Vc-loaded microemulsion showed strong antibrowning effects in apple juice at room temperature in 24h, suggesting that artocarpanone-Vc-loaded microemulsion is a good antibrowning agent for apple juices. PMID:26304444

  19. Terminal ileum submucous plexus: Study of the VIP-ergic neurons of diabetic rats treated with ascorbic acid

    Directory of Open Access Journals (Sweden)

    Zanoni Jacqueline Nelisis

    2002-01-01

    Full Text Available The aim of this study was to evaluate the effect of the ascorbic acid (AA supplementation on the neurons that produce the vasoactive intestinal peptide (VIP in the submucous plexus of the ileum of rat, four months after the induction of experimental diabetes mellitus with streptozotocin. Three groups of rats were used: C - control, D - diabetic, DA - diabetic receiving AA. We have measured the immunoreactivity and area of 80 cellular bodies of VIP-ergic neurons from each studied group. In the diabetic animals, we have observed hyperphagia, polydipsia, and an increase of glycemia and glycated hemoglobin. The VIP-ergic neurons have presented an increase of their immunoreactivity and the highest profiles when compared to the other groups. In the diabetic animals supplemented with AA it has been observed a small reduction in the glycemia and the water and food intake. We have also noticed smaller immunoreactivity in their VIP-ergic neurons, similar to what we have observed in the control group animals (group C.

  20. Fluorescence sensing of chromium (VI) and ascorbic acid using graphitic carbon nitride nanosheets as a fluorescent "switch".

    Science.gov (United States)

    Rong, Mingcong; Lin, Liping; Song, Xinhong; Wang, Yiru; Zhong, Yunxin; Yan, Jiawei; Feng, Yufeng; Zeng, Xiuya; Chen, Xi

    2015-06-15

    Using graphitic carbon nitride (g-C3N4) nanosheets, an effective and facile fluorescence sensing approach for the label-free and selective determination of chromium (VI) (Cr(VI)) was developed. The fluorescence of the solution of g-C3N4 nanosheets was quenched effectively by Cr(VI) via the inner filter effect. Under optimal conditions, a wide detection linear range for Cr(VI) was found to be from 0.6 ?M to 300 ?M with a limit of detection (LOD) of 0.15 ?M. In addition, the fluorescence of the solution of g-C3N4 nanosheets-Cr(VI) could be sensitively turned on in the presence of a reductant such as ascorbic acid (AA) via an "on-off-on" fluorescence response through the oxidation-reduction between Cr(VI) and AA. And a wide detection linear range for AA was found to be from 0.5 ?M to 200 ?M with an LOD of 0.13 ?M. Furthermore, the proposed method has the potential application for detection of Cr(VI) in lake waters and AA in biological fluids. PMID:25574860

  1. Development of crosslinked methylcellulose hydrogels for soft tissue augmentation using an ammonium persulfate-ascorbic acid redox system.

    Science.gov (United States)

    Gold, Gittel T; Varma, Devika M; Taub, Peter J; Nicoll, Steven B

    2015-12-10

    Hydrogels composed of methylcellulose are candidate materials for soft tissue reconstruction. Although photocrosslinked methylcellulose hydrogels have shown promise for such applications, gels crosslinked using reduction-oxidation (redox) initiators may be more clinically viable. In this study, methylcellulose modified with functional methacrylate groups was polymerized using an ammonium persulfate (APS)-ascorbic acid (AA) redox initiation system to produce injectable hydrogels with tunable properties. By varying macromer concentration from 2% to 4% (w/v), the equilibrium moduli of the hydrogels ranged from 1.47±0.33 to 5.31±0.71kPa, on par with human adipose tissue. Gelation time was found to conform to the ISO standard for injectable materials. Cellulase treatment resulted in complete degradation of the hydrogels within 24h, providing a reversible corrective feature. Co-culture with human dermal fibroblasts confirmed the cytocompatibility of the gels based on DNA measurements and Live/Dead imaging. Taken together, this evidence indicates that APS-AA redox-polymerized methylcellulose hydrogels possess properties beneficial for use as soft tissue fillers. PMID:26428151

  2. Arsenic induced toxicity in broiler chicks and its alleviation with ascorbic acid: a toxico-patho-biochemical study

    Science.gov (United States)

    Khan, Ahrar; Sharaf, Rabia; Khan, Muhammad Zargham; Saleemi, Muhammad Kashif; Mahmood, Fazal

    2013-01-01

    To find out toxico-pathological effects of arsenic (As) and ameliorating effect of ascorbic acid (Vit C), broilers birds were administered 50 and 250 mg/kg arsenic and Vit C, respectively alone/in combination. As-treated birds exhibited severe signs of toxicity such as dullness, depression, increased thirst, open mouth breathing and watery diarrhea. All these signs were partially ameliorated with the treatment of Vit C. As-treated birds showed a significant decrease in serum total proteins while serum enzymes, urea and creatinine were significantly increased. Alkaline phosphatase and lactate dehydrogenase completely whereas proteins, aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea and creatinine were partial ameliorated in birds treated with As+Vit C as compared to As-treated and control birds. Pale and hemorrhagic liver and swollen kidneys were observed in As-treated birds. Histopathologically, liver exhibited congestion and cytoplasmic vacuolation while in kidneys, condensation of tubular epithelium nuclei, epithelial necrosis, increased urinary spaces, sloughing of tubules from basement membrane and cast deposition were observed in As-treated birds. Pathological lesions were partially ameliorated with the treatment of Vit C. It can be concluded that arsenic induces biochemical and histopathological alterations in broiler birds; however, these toxic effects can be partially attenuated by Vit C.

  3. Chemically Modified Carbon Paste Electrodes for Ascorbic Acid Determination in Soft Drinks by Flow Injection Amperometric Analysis

    Scientific Electronic Library Online (English)

    M. Goreti F., Sales; M.S.A., Castanheira; Rosa M.S., Ferreira; M. Carmo V.F., Vaz; Cristina, Delerue-Matos.

    Full Text Available 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-je [...] t 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 optimized unvaryingly. GC electrodes present slopes of 4.75 ´ 10(5) nA L mol-1 (± 6.4 %) under optimum conditions. CP and MCP electrodes show higher sensitivity, with slopes of 6.37 ´ 10(5) nA L mol-1 (± 6.6 %) and 7.32 ´ 10(5) nA L mol-1 (± 4.4 %). Linear responses range (1.0-2.0) ´ 10-6 to (0.8-1.0) ´ 10-5 mol L-1. Correlation coefficients were > 0.994 and about 48 samples are analysed per hour. Application of the proposed method to the analysis of soft drinks is presented.

  4. Effect of ? irradiation and storage time on the ascorbic acid concentration in onion bulbs (Allium cepa L.)

    International Nuclear Information System (INIS)

    The stability of ascorbic acid (AA) of irradiated onion bulbs stored at 4 and 20 oC was studied. Gamma ionisation at 0.10; 0.15 and 0.30 kGy causes losses of 10, 13 and 20% of AA content, respectively, and the D value (Decimal Reduction Dose) of AA ionising treatment was estimated at 3.19. During the first 12 weeks of storage AA content decreased in nonirradiated and irradiated bulbs at 0.10, 0.15 and 0.30 kGy, respectively, to 4.52, 4.56, 4.81 and 5.18 mg 100 g-1 FW at 20oC. At 4oC, AA decreases to 5.92, 6.53, 6.08 and 5.92 mg 100 g-1 FW. From 12 weeks to the end of the storage period (24 weeks), AA increased but the final concentrations observed were lower than the initial levels and ranged from 15 to 30% less at 20oC, and from 5 to 20% at 4oC. (author)

  5. Electrocatalytic Oxidation of Ascorbic Acid Using a Poly(aniline-co-m-ferrocenylaniline Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Ekasith Somsook

    2011-10-01

    Full Text Available A poly(aniline-co-m-ferrocenylaniline was successfully synthesized on a glassy carbon electrode (GCE by electrochemical copolymerization using a scan potential range from ?0.3 to +0.9 V (vs. Ag/AgCl in 0.5 M H2SO4 containing 30% acetonitrile (ACN, 0.1 M aniline (Ani and 0.005 M m-ferrocenyaniline (m-FcAni. The field emission scanning electron microscope (FESEM and electrochemical methods were used to characterize the poly(Ani-co-m-FcAni modified electrode. The poly(Ani-co-m-FcAni/GCE exhibited excellent electrocatalytic oxidation of ascorbic acid (AA in citrate buffer solution (CBS, pH 5.0. The anodic peak potential of AA was shifted from +0.55 V at the bare GCE to +0.25 V at the poly(Ani-co-m-FcAni/GCE with higher current responses than those seen on the bare GCE. The scan number at the 10th cycle was selected as the maximum scan cycle in electrochemical polymerization. The limit of detection (LOD was estimated to be 2.0 mM based on the signal-to-noise ratio (S/N = 3. The amperometric responses demonstrated an excellent selectivity for AA determination over glucose (Glu and dopamine (DA.

  6. Influence of ascorbic acid supplementation on the haematological and clinical biochemistry parameters of male rabbits exposed to aflatoxin B1.

    Science.gov (United States)

    Yousef, M I; Salem, M H; Kamel, K I; Hassan, G A; El-Nouty, F D

    2003-03-01

    This study was undertaken to evaluate the effectiveness of L-ascorbic acid (AA) in alleviating the toxicity of aflatoxin B1 (AFB1) in male New-Zealand white rabbits. Five rabbits (6 months of age and mean body weight 3.12 kg) per group were assigned to 1 of 6 treatment groups: 0 mg AA and 0 mg AFB1/kg BW (control); 20 mg AA/kg BW; 15 microg AFB1/kg BW; 15 microg AFB1 plus 20 mg AA/kg BW; 30 pg AFB1/kg BW; 30 pg AFB1 plus 20 mg AA/kg BW. Rabbits were orally administered their respective doses every other day for 9 weeks, followed by a 9-week recovery period where all drugs were withdrawn. Evaluations were made for hemato-biochemical parameters and enzymatic activities. Results showed that AFB1 significantly (p urea and creatinine were not significantly affected by aflatoxin-treatment. Generally, it is interesting feature that the treatment with AA alone had no negative effects on most of the previous parameters. Also, the presence of AA could diminished the adverse effects of AFB1 on most of hematological and biochemical values, and enzymatic activities in rabbits. PMID:12617557

  7. Point-of-service, quantitative analysis of ascorbic acid in aqueous humor for evaluating anterior globe integrity

    Science.gov (United States)

    Gartia, Manas R.; Misra, Santosh K.; Ye, Mao; Schwartz-Duval, Aaron; Plucinski, Lisa; Zhou, Xiangfei; Kellner, David; Labriola, Leanne T.; Pan, Dipanjan

    2015-11-01

    Limited training, high cost, and low equipment mobility leads to inaccuracies in decision making and is concerning with serious ocular injuries such as suspected ruptured globe or post-operative infections. Here, we present a novel point-of-service (POS) quantitative ascorbic acid (AA) assay with use of the OcuCheck Biosensor. The present work describes the development and clinical testing of the paper-based biosensor that measures the changes in electrical resistance of the enzyme-plated interdigitated electrodes to quantify the level of AA present in ocular fluid. We have demonstrated the proof-of-concept of the biosensor testing 16 clinical samples collected from aqueous humor of patients undergoing therapeutic anterior chamber paracentesis. Comparing with gold standard colorimetric assay for AA concentration, OcuCheck showed accuracy of >80%, sensitivity of >88% and specificity of >71%. At present, there are no FDA-approved POS tests that can directly measures AA concentration levels in ocular fluid. We envisage that the device can be realized as a handheld, battery powered instrument that will have high impact on glaucoma care and point-of-care diagnostics of penetrating ocular globe injuries.

  8. Point-of-service, quantitative analysis of ascorbic acid in aqueous humor for evaluating anterior globe integrity.

    Science.gov (United States)

    Gartia, Manas R; Misra, Santosh K; Ye, Mao; Schwartz-Duval, Aaron; Plucinski, Lisa; Zhou, Xiangfei; Kellner, David; Labriola, Leanne T; Pan, Dipanjan

    2015-01-01

    Limited training, high cost, and low equipment mobility leads to inaccuracies in decision making and is concerning with serious ocular injuries such as suspected ruptured globe or post-operative infections. Here, we present a novel point-of-service (POS) quantitative ascorbic acid (AA) assay with use of the OcuCheck Biosensor. The present work describes the development and clinical testing of the paper-based biosensor that measures the changes in electrical resistance of the enzyme-plated interdigitated electrodes to quantify the level of AA present in ocular fluid. We have demonstrated the proof-of-concept of the biosensor testing 16 clinical samples collected from aqueous humor of patients undergoing therapeutic anterior chamber paracentesis. Comparing with gold standard colorimetric assay for AA concentration, OcuCheck showed accuracy of >80%, sensitivity of >88% and specificity of >71%. At present, there are no FDA-approved POS tests that can directly measures AA concentration levels in ocular fluid. We envisage that the device can be realized as a handheld, battery powered instrument that will have high impact on glaucoma care and point-of-care diagnostics of penetrating ocular globe injuries. PMID:26525715

  9. Simultaneous Determination of Dopamine, Sertonin and Ascorbic Acid at a Glassy Carbon Electrode Modified with Carbon-Spheres

    Directory of Open Access Journals (Sweden)

    Feng Gao

    2013-10-01

    Full Text Available 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 simultaneously detect DA, 5-HT, and AA, and the linear calibration curves for DA, 5-HT, and AA are obtained in the range of 20.0–150.0 ?M, 40.0–750.0 ?M and 300.0–2,000.0 ?M with detection limits (S/N = 3 of 2.0 ?M, 0.7 ?M and 0.6 ?M, respectively. The proposed electrode has been applied to detect DA, 5-HT, and AA in real samples using standard addition method with satisfactory results.

  10. Modulatory effects of the antioxidant ascorbic acid on the direct genotoxicity of doxorubicin in somatic cells of Drosophila melanogaster

    Scientific Electronic Library Online (English)

    Edson José, Fragiorge; Mário Antônio, Spanó; Lusânia Maria Greggi, Antunes.

    2007-03-01

    Full Text Available In this study two different crosses involving the wing cell markers mwh and flr³ (standard (ST) cross and high bioactivation (HB) cross, the latter being characterized by a high constitutive level of cytochrome P450 which leads to an increased sensitivity to a number of promutagens and procarcinogen [...] s) were used to investigate the modulatory effects of ascorbic acid (AA) combined with the antitumor agent doxorubicin (DXR) in Drosophila melanogaster. We observed that the two different concentrations of AA (50 or 100 mM) had no effect on spots frequencies, while DXR treatments (0.2 or 0.4 mM) gave positive results for all types of spots, when compared to negative control. For marker-heterozygous (MH) flies, a protective effect was observed with the lower concentration of AA (50 mM) that was able to statistically decrease the frequency of spots induced by DXR (0.2 mM), while an enhanced frequency of spots induced by DXR was observed with the higher concentration of AA (100 mM), when compared to DXR treatment (p

  11. Modulatory effects of the antioxidant ascorbic acid on the direct genotoxicity of doxorubicin in somatic cells of Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Edson José Fragiorge

    2007-03-01

    Full Text Available In this study two different crosses involving the wing cell markers mwh and flr³ (standard (ST cross and high bioactivation (HB cross, the latter being characterized by a high constitutive level of cytochrome P450 which leads to an increased sensitivity to a number of promutagens and procarcinogens were used to investigate the modulatory effects of ascorbic acid (AA combined with the antitumor agent doxorubicin (DXR in Drosophila melanogaster. We observed that the two different concentrations of AA (50 or 100 mM had no effect on spots frequencies, while DXR treatments (0.2 or 0.4 mM gave positive results for all types of spots, when compared to negative control. For marker-heterozygous (MH flies, a protective effect was observed with the lower concentration of AA (50 mM that was able to statistically decrease the frequency of spots induced by DXR (0.2 mM, while an enhanced frequency of spots induced by DXR was observed with the higher concentration of AA (100 mM, when compared to DXR treatment (p < 0.05. These results suggest that AA may interfere with free radicals generated by DXR and with other possible reactive metabolites. The efficiency of AA in protecting the somatic cells of D. melanogaster against mutation and recombination induced by DXR is dependent on the dose used and the protection is directly related to the activity of cytochrome P450 enzymes.

  12. Serum biochemical activities and muscular soreness in transported goats administered with ascorbic acid during the hot-dry season

    Directory of Open Access Journals (Sweden)

    Ndazo S Minka

    2010-12-01

    Full Text Available The effects of handling, loading and 12 h of road transportation during the hot-dry season on muscular metabolism of 20 experimental goats administered orally with 100 mg/kg body weight of ascorbic acid (AA dissolved in 10 ml of sterile water, and other 20 control goats given equivalent of sterile water 40 min prior to transportation were investigated. The result obtained post-transportation showed that handling, loading and transportation were stressful to the goats, especially the control goats and resulted into muscular damage and the development of delayed-onset-muscular-soreness (DOMS, which may lead to dark-firm-dry (DFD syndrome meat with undesirable effects on its quality. In the experimental goats administered AA such transportation effects were minimal or completely abolished. The result demonstrated that AA reduced the incidence of DOMS and muscular damage in transported goats, therefore it may be used to improve the welfare and quality of meat obtained from goats subjected to long period of road transportation under adverse climatic conditions.

  13. Colourimetric solid-phase extraction coupled with fibre optic reflectance spectroscopy for determination of ascorbic acid in pharmaceutical formulations.

    Science.gov (United States)

    Filik, Hayati; Aksu, Duygu; Giray, Derya; Apak, Re?at

    2012-06-01

    A redox colourimetric solid-phase extraction (C-SPE) procedure for the determination of ascorbic acid (AA) in pharmaceutical formulations was proposed. Iron (III)-2,2'-dipyridyl (Fe(III)-Bpy) reagent solution was used as a colouring reagent for AA and the immobilization of the redox product onto Amberlite XAD-16 resin was achieved. The analyte in the sample reacted with a solid sorbent loaded with the colourimetric reagent (Fe(III)-Bpy) and then quantified directly on the sorbent surface by using a fibre optic reflectance spectrometer (FORS). The amount of AA was reflectometrically determined in a few seconds with a total sample workup and readout time of ?10 min using only 10-ml sample volumes. The limit of detection (LOD) and quantification (LOQ) values were 0.18 and 0.6 mg L(-1), respectively, and the linear dynamic range for AA extended up to 8.8 mg L(-1). The C-SPE for different extractions (n = 5) gave a relative standard deviation (RSD) of 2.9% at 5.28 mg L(-1) AA level. PMID:21337723

  14. Multiwall carbon nanotube modified glassy carbon electrode as voltammetric sensor for the simultaneous determination of ascorbic acid and caffeine

    International Nuclear Information System (INIS)

    Highlights: ? Performance of bare and modified GCE for the study of oxidation of drugs. ? MWCNT/MGCE used for determination of AA and CAF in various samples. ? It is demonstrated that the modified electrode is better than the bare GCE. ? AA and CAF are quantified in tea leaves, coffee, cold drink, urine samples. - Abstract: Simultaneous determination of ascorbic acid (AA) and caffeine (CAF) in pharmaceutical preparation is important and it has been achieved by square wave voltammetry (SWV) using a glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNT). The oxidation of AA and CAF at MWCNT occurred at ??10 mV and ?1103 mV at a much lower potential, than that observed (?202 mV and ?1402 mV) for their oxidation at bare GCE. The mechanistic study has shown that the equal number of electrons and protons are involved in the oxidation of drugs. The electrodes could be used for the determination of AA and CAF in a wide concentration range 10–500 ?M, respectively, whereas the detection limit has been found to be 1.0 × 10?2 ?M and 3.52 × 10?3 ?M respectively. In view of high sensitivity for the detection of the drugs, the technique has been used for the reliable determination of AA and CAF in tea leaves, coffee, cold drink (mountain dew), pharmaceutical preparations and urine samples

  15. Fe(3+)-functionalized carbon quantum dots: A facile preparation strategy and detection for ascorbic acid in rat brain microdialysates.

    Science.gov (United States)

    Li, Linbo; Wang, Chao; Luo, Jingxuan; Guo, Quanwei; Liu, Kangyu; Liu, Kun; Zhao, Wenji; Lin, Yuqing

    2015-11-01

    This study reports an Fe(3+)-functionalized carbon quantum dots (Fe(3+)-functionalized CQDs) for the highly sensitive and selective detection of ascorbic acid (AA) in rat brain microdialysates based on the specific redox reaction between iron(III) ions and AA. The carbon quantum dots (CQDs) were synthesized by one-step pyrolysis of a small organic molecules i.e. tris(hydroxymethyl)aminomethane (Tris). Fe(3+) can tightly chelate to the surface of CQDs by the hydroxyl group to form Fe(3+)-functionalized CQDs while the fluorescence of CQDs can be effectively quenched by Fe(3+) via Fluorescence resonance energy transfer (FRET). The fluorescence of the Fe(3+)-functionalized CQDs can be sensitively turned on by AA to give an "on-off-on" fluorescence response through the oxidation-reduction between Fe(3+) and AA since the produced Fe(2+) has much lower chelating ability to CQDs and the fluorescence of CQDs can be restored. This Fe(3+)-functionalized CQDs based nanoprobe shows high selective and sensitive response in the concentration of AA ranging from 0.1?M to 50?M with the detection limit as lower as 9.1nM, which is lower than other assays. Finally, the proposed fluorescent probe was successfully applied to direct analysis of AA in biological fluids, i.e. rat brain microdialysates, and may pave a new route to the design of effective carbon quantum dots-based fluorescence probes for other bioassay. PMID:26452962

  16. Improvement of the healing of a rat tibia defect by means of a Calcium Carbonate based biopolymer mixed with Epidermal Growth Factor and Ascorbic Acid

    Science.gov (United States)

    Mendoza-Barrera, C.; Meléndez-Lira, M.; Hernández-Flores, C.; Lecona-Butrón, H.; García-López, E. S.

    2000-10-01

    At the present bone reparation is commonly solved by means of different graft types. Biomaterials such as hidroxyapatite, coraline, octacalcium phosphate and tricalcium phosphate are used. By other side there are factors like Epidermal Growth Factor (EGF), Fibroblast Growth Factor (TGF), Laminine, Ascorbic Acid (AA), etc. that stimulate the osteogenesis in fracture or bony defect. The goal of this work is to evaluate the effect of the addition of EGF and ascorbic acid to a Ca2CO3 based biopolymer in the healing of a rat tibia model to improve the consolidation with adequate bony quality. No implant rejection or inflammatory reaction was observed during a 5 weeks period in our in vivo studies. The evolution of the osteointegration has been followed employing scanning electronic microscopy (SEM), energy dispersive x-ray analysis (EDX), and biochemistry activity for calcium, phosphor and alkaline phosphatase. We conclude that the combined use of the based Ca2CO3 biopolymer with Ascorbic Acid and Epidermal Growth Factor (group B&AA&EGF) in vivo accelerates the process of bony repair, as compared with the other groups. The mixture B&AA&EGF provide a bridge in the lesion, helping in the cellular migration and increasing the collagen synthesis.

  17. A convenient strategy to functionalize carbon nanotubes with ascorbic acid and its effect on the physical and thermomechanical properties of poly(amide–imide) composites

    International Nuclear Information System (INIS)

    Multi-walled carbon nanotubes (MWCNTs) were functionalized by ascorbic acid by a fast strategy under microwave irradiation to improve interfacial interactions and dispersion of CNTs in a poly(amide–imide) (PAI) matrix. This technique provides a rapid and economically viable route to produce covalently functionalized CNTs. The as-prepared, new type of functionalized CNTs were analyzed by several techniques. The thermal stabilities and mechanical interfacial properties of CNT/PAI composites were investigated using several techniques. The dispersion state of CNTs in the PAI matrix was observed by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The mechanical interfacial property of the composites was significantly increased by the addition of ascorbic acid treated CNTs. The FE-SEM and TEM results showed that the separation and uniform dispersion of CNTs in the PAI matrix. The overview of these recent results is presented. -- Graphical abstract: Presentation of possible interactions of hydrogen bonding between the MWCNT-AS and the PAI chains. Highlights: • Surface functionalization of MWCNTs with ascorbic acid under microwave irradiation. • The MWCNT-AS/PAI composite films were fabricated by solution blending process. • Microstructure and MWCNT states in the composites were studied. • Thermal and mechanical properties of the composite films were evaluated. • Films of different contents of the MWCNTs-AS showed a superior tensile behavior

  18. Modification of carbon paste electrode with Fe(III)-clinoptilolite nano-particles for simultaneous voltammetric determination of acetaminophen and ascorbic acid.

    Science.gov (United States)

    Sharifian, Samira; Nezamzadeh-Ejhieh, Alireza

    2016-01-01

    A novel carbon paste electrode (CPE) modified with Fe(III)-exchanged clinoptilolite nano-particles (Fe(III)-NClino/CPE) was constructed and used for simultaneous voltammetric (CV, SqW and chronoamperometry) determination of ascorbic acid and acetaminophen. Raw and modified zeolites were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The square wave peak current was linearly increased in the concentration ranges of 1.0×10(-9)-1.0×10(-2) mol L(-1) for ascorbic acid and 1.0×10(-10-)1.0×10(-2) mol L(-1) for acetaminophen with detection limits of 1.8×10(-9) mol L(-1) and 9.9×10(-10) mol L(-1), respectively. The detection limits of 2.4×10(-10) mol L(-1) and 2.5×10(-11) mol L(-1) were also obtained for AA and AC in chronoamperometric measurements, respectively. The diffusion coefficients of 7.5×10(-5) cm(2) s(-1) and 2.4×10(-5) cm(2) s(-1) were respectively calculated for the oxidation of AC and AA by chronoamperometry. The proposed electrode exhibited high sensitivity and good stability, and would be valuable for the clinical assay of ascorbic acid and acetaminophen. PMID:26478339

  19. A convenient strategy to functionalize carbon nanotubes with ascorbic acid and its effect on the physical and thermomechanical properties of poly(amide–imide) composites

    Energy Technology Data Exchange (ETDEWEB)

    Mallakpour, Shadpour, E-mail: mallak@cc.iut.ac.ir [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, I.R. Iran (Iran, Islamic Republic of); Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan 84156-83111, I.R. Iran (Iran, Islamic Republic of); Zadehnazari, Amin [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, I.R. Iran (Iran, Islamic Republic of)

    2014-03-15

    Multi-walled carbon nanotubes (MWCNTs) were functionalized by ascorbic acid by a fast strategy under microwave irradiation to improve interfacial interactions and dispersion of CNTs in a poly(amide–imide) (PAI) matrix. This technique provides a rapid and economically viable route to produce covalently functionalized CNTs. The as-prepared, new type of functionalized CNTs were analyzed by several techniques. The thermal stabilities and mechanical interfacial properties of CNT/PAI composites were investigated using several techniques. The dispersion state of CNTs in the PAI matrix was observed by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The mechanical interfacial property of the composites was significantly increased by the addition of ascorbic acid treated CNTs. The FE-SEM and TEM results showed that the separation and uniform dispersion of CNTs in the PAI matrix. The overview of these recent results is presented. -- Graphical abstract: Presentation of possible interactions of hydrogen bonding between the MWCNT-AS and the PAI chains. Highlights: • Surface functionalization of MWCNTs with ascorbic acid under microwave irradiation. • The MWCNT-AS/PAI composite films were fabricated by solution blending process. • Microstructure and MWCNT states in the composites were studied. • Thermal and mechanical properties of the composite films were evaluated. • Films of different contents of the MWCNTs-AS showed a superior tensile behavior.

  20. Radioprotection potential of the ascorbic acid on the carrageenan used as food additive; Potencial radioprotetor do acido ascorbico sobre a carragenana utilizada como aditivo alimenticio

    Energy Technology Data Exchange (ETDEWEB)

    Aliste, Antonio Joao; Mastro, Nelida Lucia del [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: ajaliste@net.ipen.br; nlmastro@net.ipen.br

    2002-07-01

    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 {sup 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)

  1. Involvement of Nitrogen on Flavonoids, Glutathione, Anthocyanin, Ascorbic Acid and Antioxidant Activities of Malaysian Medicinal Plant Labisia pumila Blume (Kacip Fatimah

    Directory of Open Access Journals (Sweden)

    Zaharah Abdul Rahman

    2011-12-01

    Full Text Available A split plot 3 by 4 experiment was designed to characterize the relationship between production of gluthatione (GSH, oxidized gluthatione (GSSG, total flavonoid, anthocyanin, ascorbic acid and antioxidant activities (FRAP and DPPH in three varieties of Labisia pumila Blume, namely the varieties alata, pumila and lanceolata, under four levels of nitrogen fertilization (0, 90, 180 and 270 kg N/ha for 15 weeks. The treatment effects were solely contributed by nitrogen application; there was neither varietal nor interaction effects observed. As the nitrogen levels decreased from 270 to 0 kg N/ha, the production of GSH and GSSG, anthocyanin, total flavonoid and ascorbic acid increased steadily. At the highest nitrogen treatment level, L. pumila exhibited signi?cantly lower antioxidant activities (DPPH and FRAP than those exposed to limited nitrogen growing conditions. Significant positive correlation was obtained between antioxidant activities (DPPH and FRAP, total flavonoid, GSH, GSSG, anthocyanin and ascorbic acid suggesting that an increase in the antioxidative activities in L. pumila under low nitrogen fertilization could be attributed to higher contents of these compounds. From this observation, it could be concluded that in order to avoid negative effects on the quality of L. pumila, it is advisable to avoid excessive application of nitrogen fertilizer when cultivating the herb for its medicinal use.

  2. Application of l-ascorbic acid and its derivatives (sodium ascorbyl phosphate and magnesium ascorbyl phosphate) in topical cosmetic formulations: stability studies

    International Nuclear Information System (INIS)

    The present study aimed to formulate and subsequently evaluate a topical skin-care cream (o/w emulsion) from l-ascorbic acid and its derivatives (sodium ascorbyl phosphate and magnesium ascorbyl phosphate) at 2% versus its vehicle (Control). Formulations were developed by entrapping it in the oily phase of o/w emulsion and were stored at 8 degree C, 25 degree C and 40 degree C (in incubator) for a period of four weeks to investigate their stability. In the physical analysis, the evaluation parameters consisted of color, smell, phase separation, centrifugation, and liquefaction. Chemical stability of both derivatives was established by HPLC analysis. In the chemical analysis, the formulation with sodium ascorbyl phosphate was more stable than those with magnesium ascorbyl phosphate and l-ascorbic acid. The microbiological stability of the formulations was also evaluated. The findings indicated that the formulations with l-ascorbic acid and its derivatives were efficient against the proliferation of various spoilage microorganisms, including aerobic plate counts as well as Pseudomonas aeruginosa, Staphylococcus aureus, and yeast and mold counts. The results presented in this work showed good stability throughout the experimental period. Newly formulated emulsion proved to exhibit a number of promising properties and attributes that might open new opportunities for the construction of more efficient, safe, and cost-effective skin-care, cosmetic, and pharmaceutical products. (author)

  3. Tuning Surface Charge and Morphology for the Efficient Detection of Dopamine under the Interferences of Uric Acid, Ascorbic Acid, and Protein Adsorption.

    Science.gov (United States)

    Chen, Chien-Hsun; Luo, Shyh-Chyang

    2015-10-01

    In this research, we aimed to evaluate the impact of the surface charges and morphologies of electrodes on electrochemically detecting dopamine (DA) in the presence of protein adsorption, uric acid (UA), and ascorbic acid (AA). Through the electropolymerization of functionalized 3,4-ethylenedioxythiophenes (EDOT) directly on Au electrodes, we successfully created PEDOT-coated electrodes with three different functional groups and nanostructures. Negatively charged carboxylic acid groups attracted DA while reducing the interferences of UA and AA due to electrostatic effect. We used charge-free tetra(ethylene glycol) and zwitterionic phosphocholine groups are used to evaluate the interference of protein adsorption on DA sensing because they both can effectively prevent the nonspecific adsorption of proteins. These two electrodes can avoid protein adsorption, yet proved ineffective for DA sensing: both tetra(ethylene glycol) and the phosphocholine groups are electroneutral and have minimal electrostatic interactions with DA. We also used three proteins of different isoelectric points - bovine serum albumin, lysozyme, and fibrinogen - to evaluate the influence of protein adsorption on DA detection. We found that for an electrode coated with carboxylic acid-functionalized PEDOT, the adsorption of positively charged lysozyme can promote the detection sensitivity of AA and UA, and that all protein adsorption lowers the sensitivity of DA. In contrast, nanostructures promote the detection sensitivity of all three molecules. All of our tested functionalized PEDOT-coated electrodes demonstrated good stability and functionality in buffers. PMID:26381224

  4. Susceptibility of Propionibacterium acnes isolated from patients with acne vulgaris to zinc ascorbate and antibiotics

    Science.gov (United States)

    Iinuma, Katsuhiro; Noguchi, Norihisa; Nakaminami, Hidemasa; Sasatsu, Masanori; Nishijima, Setsuko; Tsuboi, Isami

    2011-01-01

    Purpose: The in vitro antimicrobial activity of ascorbic acid derivatives against Propionibacterium acnes was tested either alone or in combination with a variety of antimicrobial agents, and their fractional inhibitory concentration index was determined using checkerboard tests. The antimicrobial effectiveness of zinc ascorbate in the treatment of acne vulgaris, either alone or in combination with antibiotics such as clindamycin that are commonly used in Japan for the treatment of acne vulgaris, was therefore examined. Materials and methods: The antimicrobial susceptibility of 41 strains of clindamycin-sensitive and/or clindamycin-resistant P. acnes isolated from acne vulgaris patients was tested, in comparison with a type strain of P. acnes. Results: Zinc ascorbate showed antimicrobial activity against a type strain of P. acnes and its concentration (0.064%) was sufficiently lower than the normal dose (5%) of other ascorbic acid derivatives. Combinations of zinc ascorbate with clindamycin, erythromycin, and chloramphenicol showed an additive effect, and zinc ascorbate alone effectively inhibited the growth of all P. acnes including clindamycin-resistant strains. Conclusion: The results provide novel evidence that the combination of zinc ascorbate and clindamycin is effective for acne vulgaris treatment. PMID:22087070

  5. Effect of varying concentrations of caffeine and ascorbic acid on the radiosensitivity of barley seed irradiated in oxygenated or oxygen-free hydration medium at 25 and 3700C

    International Nuclear Information System (INIS)

    The modification of radiosensitivity of barley seed with 1.75 x 10-3M and 3.8 x 10-3M concentrations of caffeine and ascorbic acid during irradiation in oxygenated and oxygen-free hydration medium was studied at 25 and 370C, respectively. Both concentrations of caffeine and ascorbic acid afforded protection against oxic radiation damage which was maximal at 250C. Caffeine effectively potentiated the anoxic component of damage but ascorbic acid had no influence at all. At 250C there was no concentration-dependent effect of caffeine or ascorbic acid. At 370C, there was no effect, whatsoever, of either concentration of ascorbic acid, whereas caffeine dramatically potentiated the radiation damage under both oxygenated and oxygen-free conditions, and the magnitude of potentiation was concentration-dependent. The possible reactivity of caffeine and ascorbic acid towards the precursors of oxygen-dependent and -independent components of damage in determining the mode and magnitudes of modification is discussed briefly. (author)

  6. Estabilidade de ácido ascórbico em sucos de frutas frescos sob diferentes formas de armazenamento / Ascorbic acid stability in fresh fruit juice under different forms of storage

    Scientific Electronic Library Online (English)

    Kelly Damasceno, Cunha; Priscila Ribeiro da, Silva; Ana Lígia Faria e Silva da Fonseca, Costa; Anderson Junger, Teodoro; Maria Gabriela Bello, Koblitz.

    2014-06-01

    Full Text Available O ácido ascórbico é uma vitamina hidrossolúvel de importância nutricional há muito estabelecida, por sua atuação como cofator em diversos processos fisiológicos e como antioxidante. O ser humano depende da ingestão diária desse micronutriente, cujas principais fontes são as frutas e hortaliças. Por [...] ser um nutriente menos estável, o ácido ascórbico sofre perdas no processamento e no armazenamento, influenciadas por diversos fatores, como pH, temperatura, presença de íons, etc. A literatura apresenta escasso material sobre a estabilidade de ácido ascórbico em armazenamento doméstico, além de haver poucas informações sobre essa vitamina em sucos frescos. A metodologia padrão de análise dessa vitamina em sucos é o Método Titulométrico de Tillmans, que pode apresentar ponto de viragem de difícil visualização. Neste trabalho, foram avaliadas a concentração e a estabilidade do ácido ascórbico de sucos comerciais recém-preparados de laranja, abacaxi com hortelã e melancia, armazenados sob refrigeração e em temperatura ambiente, por dois métodos titulométricos distintos. O método alternativo de análise (NBS) superestimou a concentração de ácido ascórbico das amostras. Não houve diferença significativa na estabilidade da vitamina em sucos armazenados em temperaturas entre 6 e 30ºC, no período testado. O ácido ascórbico foi estável por 24h no suco de laranja, porém apresentou decréscimo significativo após 8h de armazenamento nos sucos de abacaxi e melancia, possivelmente em virtude das diferenças de acidez inicial desses sucos. Em comparação com a literatura disponível, verificou-se que sucos frescos apresentaram menor estabilidade de ácido ascórbico do que sucos industrializados. Abstract in english Ascorbic acid is a water soluble vitamin of long-established nutritional importance for its role as a cofactor in many physiological processes and as an antioxidant. Human beings depend on daily intake of this micronutrient, whose main sources are fruits and vegetables. As the least stable nutrient, [...] ascorbic acid suffers losses during processing and storage, influenced by several factors (pH, temperature, presence of ions, etc.). The literature provides little material on the stability of ascorbic acid in home storage and there is little information about this vitamin in fresh juices. The standard methodology for analysis of this vitamin in juices is the titrimetric method of Tillmans, which can present difficulties in visualizing the turning point. In this study, the concentration and stability of ascorbic acid in freshly prepared commercial juices of orange, pineapple with mint and watermelon, stored under refrigeration or at room temperature, were evaluated with two different titrimetric methods. The alternative method of analysis (NBS) overestimated the ascorbic acid concentration of the samples. There was no significant difference in the stability of this vitamin in juices stored in temperatures between 6 and 30ºC during the testing period. Ascorbic acid was stable for 24 h in orange juice, but showed significant decrease after 8 h storage in pineapple and watermelon juices, possibly due to differences in initial acidity of these juices. In comparison to the available literature it was found that fresh juices had lower ascorbic acid stability than industrialized juices.

  7. Selective determination of 3,4-dihydroxyphenylacetic acid in the presence of ascorbic and uric acids using polymer film modified electrode

    Indian Academy of Sciences (India)

    Palraj Kalimuthu; S Abraham John

    2011-05-01

    We report here the highly sensitive and selective electrochemical determination of 3,4-dihydroxyphenylacetic acid (DOPAC), one of the dopamine metabolites in the presence of important interferents ascorbic acid (AA) and uric acid (UA) using an ultrathin electropolymerized film of 5-amino-1,3,4-thiadiazole-2-thiol (p-ATT) modified glassy carbon (GC) electrode in 0.20M phosphate buffer solution (pH 5.0). The bare GC electrode fails to resolve the oxidation peaks of AA, DOPAC and UA in a mixture. Further, the oxidation peak potentials of them were shifted to more positive potential with decreased peak currents in the subsequent cycles. On the other hand, the p-ATT modified electrode not only separated the voltammetric signals of AA, DOPAC and UA but also enhanced their peak currents. The amperometric current response was increased linearly with increasing DOPAC concentration in the range of $4.0 \\times 10^{?8}$ to $1.0 \\times 10^{?5}$ M and the detection limit was found to be 150pM ($S/N =3$).

  8. Electron paramagnetic resonance study of hydrogen peroxide/ascorbic acid ratio as initiator redox pair in the inulin-gallic acid molecular grafting reaction.

    Science.gov (United States)

    Arizmendi-Cotero, Daniel; Gómez-Espinosa, Rosa María; Dublán García, Octavio; Gómez-Vidales, Virginia; Dominguez-Lopez, Aurelio

    2016-01-20

    Gallic acid (GA) was grafted onto inulin using the free radicals method, generated by the hydrogen peroxide/ascorbic acid (H2O2/AA) redox pair. Molar ratios of H2O2/AA at 9, 20, 39 and 49 were evaluated by Electron Paramagnetic Resonance in order to find the effect of the oxidation of the inulin and the efficiency in the inulin-gallic acid grafting (IGA). The highest concentration of the inulin macro-radical was obtained with H2O2/AA molar ratios of 20 and 49 with the removal of a hydrogen atom from a methyl group of the inulin fructose monomers. The highest grafting ratio (30.4mg GA eq/g IGA) was obtained at 9M of H2O2/AA. UV-Vis, FT-IR-ATR and XDR results confirmed a successful IGA grafting. The efficiency of the grafting reaction depends on the concentration of the macro-radical, it depends on the molar ratio of H2O2/AA, being affected by simultaneous reactions between components of the mixture (H2O2, AA, inulin, GA and eventually atmospheric oxygen) as well. PMID:26572365

  9. Combined effect of gamma irradiation, ascorbic acid, and edible coating on the improvement of microbial and biochemical characteristics of ground beef.

    Science.gov (United States)

    Ouattara, Blaise; Giroux, Martine; Smoragiewicz, Wanda; Saucier, Linda; Lacroix, Monique

    2002-06-01

    This study was conducted to evaluate the combined effect of gamma irradiation and the incorporation of natural antimicrobial compounds in cross-linked films on the microbiological and biochemical characteristics of ground beef. Medium-fat (23% fat) ground beef patties were divided into three separate treatment groups: (i) control samples without additives, (ii) ground beef samples containing 0.5% (wt/wt) ascorbic acid, and (iii) ground beef samples containing 0.5% ascorbic acid and coated with a protein-based cross-linked film containing immobilized spice powders. Meat samples were irradiated at doses of 0, 1, 2, and 3 kGy and stored at 4 +/- 2 degrees C. Microbial growth (based on total aerobic plate counts [APCs] and total coliforms) was evaluated, as were the content of thiobarbituric acid-reactive substances (TBARS) and that of free sulfydryl groups. At the end of the storage period, Enterobacteriaceae, presumptive Staphylococcus aureus, presumptive Pseudomonas spp., Brochothrix thermosphacta, and lactic acid bacteria were enumerated. Regardless of the treatment group, irradiation significantly (P < or = 0.05) reduced the APCs. Irradiation doses of 1, 2, and 3 kGy produced immediate APC reductions of 2, 3, and 4 log units, respectively. An APC level of 6 log CFU/g was reached after 4, 7, and 10 days for samples irradiated at 1, 2, and 3 kGy, respectively. Lactic acid bacteria and B. thermosphacta were more resistant to irradiation than were Enterobacteriaceae and Pseudomonas. The TBARS and free sulfydryl contents were stabilized during postirradiation storage for samples containing ascorbic acid and coated with the protein-based cross-linked film containing immobilized spice powders. PMID:12092732

  10. Direct electrodeposition of gold nanotube arrays of rough and porous wall by cyclic voltammetry and its applications of simultaneous determination of ascorbic acid and uric acid

    Energy Technology Data Exchange (ETDEWEB)

    Yang Guangming, E-mail: yangguangmingbs@126.com [Department of Resources and Environment, Baoshan University, Baoshan 678000 (China); Li Ling [Department of Resources and Environment, Baoshan University, Baoshan 678000 (China); Jiang Jinhe; Yang Yunhui [College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650092 (China)

    2012-08-01

    Gold nanotube arrays of rough and porous wall has been synthesized by direct electrodeposition with cyclic voltammetry utilizing anodic aluminum oxide template (AAO) and polycarbonate membrane (PC) during short time (only 3 min and 2 min, respectively). The mechanism of the direct electrodeposition of gold nanotube arrays by cyclic voltammetry (CV) has been discussed. The morphological characterizations of the gold nanotube arrays have been investigated by scanning electron microscopy (SEM). A simultaneous determination of ascorbic acid (AA) and uric acid (UA) by differential pulse voltammetry (DPV) was constructed by attaching gold nanotube arrays (using AAO) onto the surface of a glassy carbon electrode (GCE). The electrochemical behavior of AA and UA at this modified electrode has been studied by CV and differential pulse voltammetry (DPV). The sensor offers an excellent response for AA and UA and the linear response range for AA and UA were 1.02 Multiplication-Sign 10{sup -7}-5.23 Multiplication-Sign 10{sup -4} mol L{sup -1} and 1.43 Multiplication-Sign 10{sup -7}-4.64 Multiplication-Sign 10{sup -4} mol L{sup -1}, the detection limits were 1.12 Multiplication-Sign 10{sup -8} mol L{sup -1} and 2.24 Multiplication-Sign 10{sup -8} mol L{sup -1}, respectively. This sensor shows good regeneration, stability and selectivity and has been used for the determination of AA and UA in real human urine and serum samples with satisfied results. - Graphical abstract: The schematic diagram of formation of Au nanotube arrays (a) and the stepwise procedure of the sensor (b). Highlights: Black-Right-Pointing-Pointer Gold nanotubes array has been synthesized by cyclic voltammetry. Black-Right-Pointing-Pointer The mechanism of deposition of gold nanotube has been discussed. Black-Right-Pointing-Pointer A determination of ascorbic acid and uric acid was constructed by gold array. Black-Right-Pointing-Pointer A satisfied determination of samples can be obtained by this sensor.

  11. When Good Intentions Go Awry: Modification of a Recombinant Monoclonal Antibody in Chemically Defined Cell Culture by Xylosone, an Oxidative Product of Ascorbic Acid.

    Science.gov (United States)

    Chumsae, Chris; Hossler, Patrick; Raharimampionona, Haly; Zhou, Yu; McDermott, Sean; Racicot, Chris; Radziejewski, Czeslaw; Zhou, Zhaohui Sunny

    2015-08-01

    With the advent of new initiatives to develop chemically defined media, cell culture scientists screen many additives to improve cell growth and productivity. However, the introduction or increase of supplements, typically considered beneficial or protective on their own, to the basal media or feed stream may cause unexpected detrimental consequences to product quality. For instance, because cultured cells are constantly under oxidative stress, ascorbic acid (vitamin C, a potent natural reducing agent) is a common additive to cell culture media. However, as reported herein, a recombinant monoclonal antibody (adalimumab) in cell culture was covalently modified by xylosone (molecular weight 148), an oxidative product of ascorbate. Containing reactive carbonyl groups, xylosone modifies various amines (e.g., the N-termini of the heavy and light chains and susceptible lysines), forming either hemiaminal (+148 Da) or Schiff base (imine, +130 Da) products. Our findings show, for the first time, that ascorbate-derived xylosone can contribute to an increase in molecular heterogeneity, such as acidic species. Our work serves as a reminder that additives to cell culture and their metabolites may become reactive and negatively impact the overall product quality and should be carefully monitored with any changes in cell culture conditions. PMID:26151084

  12. [Lead detoxication effect of a combined calcium phosphate and ascorbic acid therapy in pregnant women with increased lead burden (author's transl)].

    Science.gov (United States)

    Altmann, P; Maruna, R F; Maruna, H; Michalica, W; Wagner, G

    1981-01-01

    In former papers it was stated that the fetus can be exposed a considerable burden by traces of heavy metals and that a combined therapy with calcium phosphate and ascorbic acid has a good detoxifying effect. In fourty lead-burdened mothers who were treated in this way the excretion of 5-aminolevulinic acid in urine decreased by 65%, the lead content of placenta by 90% and the lead content of mother's milk by 15% compared with a control group without treatment. The cadmium content of the placenta was reduced to 4% of the content in untreated mothers. PMID:7293190

  13. Annexin V assay-proven anti-apoptotic effect of ascorbic acid 2-glucoside after cold ischemia/reperfusion injury in rat liver transplantation.

    Directory of Open Access Journals (Sweden)

    Liu J

    2003-10-01

    Full Text Available Controversy exists over whether the predominant cell death of hepatocytes is due to apoptosis or necrosis after ischemia/reperfusion injury. In this study we investigated the predominant cell death of hepatocytes after cold ischemia/reperfusion injury using the Annexin V-based assay, and evaluated the anti-apoptotic effect of ascorbic acid 2-glucoside (AA-2G added to the University of Wisconsin solution (UW solution in rat liver transplantation. The retrieved liver was preserved in 4 UW solution for 24 h, and then transplanted orthotopically to the syngeneic Wistar recipient. The animals were divided into 2 groups, a control group (n=10, in which liver grafts were preserved in UW solution (4, and an AA-2G group (n=10, in which liver grafts were preserved in UW solution (4 with AA-2G (100 ug/ml. The serum AST level 4 h after reperfusion in the control group was significantly suppressed in the AA-2G group, and the bile production of the liver graft in the AA-2G group was well recovered. The mean survival time in the AA-2G group was significantly improved compared with that in the control group. Annexin-V and Propidium iodide staining 4 h after reperfusion showed a significantly higher percentage of viable hepatocytes in the AA-2G group compared with the control group (93.4 +/- 2.0 vs. 80.3 +- 2.1%, P<0.05. In the control group, the main cell death of hepatocytes was apoptosis (early apoptosis: 10.0 +- 4.7%, late apoptosis: 6.4 +/- 1.7%. The addition of AA-2G to the UW solution significantly inhibited both early and late apoptotic cell death 4 h after reperfusion (early apoptosis: 0.98 +/- 0.88%, late apoptosis: 2.2 +/- 1.1%. The expression of caspase 9 in the immunostaining of the liver graft was suppressed in the AA-2G group compared with in the control group. Our study using the Annexin V-based assay provided evidence that the predominant cell death of hepatocytes was apoptosis after 24 h cold ischemia/reperfusion injury in rat liver transplantation. The addition of AA-2G to the UW solution attenuated 24 h cold ischemia/reperfusion injury by inhibiting the apoptosis of hepatocytes.

  14. Annexin V assay-proven anti-apoptotic effect of ascorbic acid 2-glucoside after cold ischemia/reperfusion injury in rat liver transplantation.

    Science.gov (United States)

    Liu, Jie; Yagi, Takahito; Sadamori, Hiroshi; Matsukawa, Hiroyoshi; Sun, Dong-Sheng; Mitsuoka, Naoshi; Yamamura, Masao; Matsuoka, Junji; Jin, Zaishun; Yamamoto, Itaru; Tanaka, Noriaki

    2003-10-01

    Controversy exists over whether the predominant cell death of hepatocytes is due to apoptosis or necrosis after ischemia/reperfusion injury. In this study we investigated the predominant cell death of hepatocytes after cold ischemia/reperfusion injury using the Annexin V-based assay, and evaluated the anti-apoptotic effect of ascorbic acid 2-glucoside (AA-2G) added to the University of Wisconsin solution (UW solution) in rat liver transplantation. The retrieved liver was preserved in 4 UW solution for 24 h, and then transplanted orthotopically to the syngeneic Wistar recipient. The animals were divided into 2 groups, a control group (n=10), in which liver grafts were preserved in UW solution (4), and an AA-2G group (n=10), in which liver grafts were preserved in UW solution (4) with AA-2G (100 ug/ml). The serum AST level 4 h after reperfusion in the control group was significantly suppressed in the AA-2G group, and the bile production of the liver graft in the AA-2G group was well recovered. The mean survival time in the AA-2G group was significantly improved compared with that in the control group. Annexin-V and Propidium iodide staining 4 h after reperfusion showed a significantly higher percentage of viable hepatocytes in the AA-2G group compared with the control group (93.4 +/- 2.0 vs. 80.3 +- 2.1%, P<0.05). In the control group, the main cell death of hepatocytes was apoptosis (early apoptosis: 10.0 +- 4.7%, late apoptosis: 6.4 +/- 1.7%). The addition of AA-2G to the UW solution significantly inhibited both early and late apoptotic cell death 4 h after reperfusion (early apoptosis: 0.98 +/- 0.88%, late apoptosis: 2.2 +/- 1.1%). The expression of caspase 9 in the immunostaining of the liver graft was suppressed in the AA-2G group compared with in the control group. Our study using the Annexin V-based assay provided evidence that the predominant cell death of hepatocytes was apoptosis after 24 h cold ischemia/reperfusion injury in rat liver transplantation. The addition of AA-2G to the UW solution attenuated 24 h cold ischemia/reperfusion injury by inhibiting the apoptosis of hepatocytes. PMID:14679398

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

    Science.gov (United States)

    Abhilash, P A; Harikrishnan, R; Indira, M

    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 4g/kg b.wt for 90days. After 90days, ethanol administration was stopped. The ethanol treated animals were divided into abstention, silymarin (250mg/kg b.wt) and AA (250mg/kg b.wt) supplemented groups and maintained for 30days. 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. PMID:24239723

  16. Sensitive electrochemical detection of vaccinia virus in a solution containing a high concentration of L-ascorbic acid.

    Science.gov (United States)

    Park, Seonhwa; Kim, Jihye; Ock, Hwiseok; Dutta, Gorachand; Seo, Jeongwook; Shin, Eui-Cheol; Yang, Haesik

    2015-08-21

    Washing processes cannot fully remove interfering species that remain on biosensing surfaces when a sample solution contains a high concentration of interfering species. This study reports an immunosensing scheme employing electroreduction-based electrochemical-chemical (EC) redox cycling that allows sensitive detection of vaccinia virus (VV) in a solution containing a high concentration of L-ascorbic acid (AA). To obtain high signal amplification, an enzymatic reaction by ?-D-galactosidase (Gal) is combined with electroreduction-based EC redox cycling by an oxidant. Among the four possible oxidants (KIO3, NaClO, Ag2O, and H2O2), KIO3 shows the highest signal-to-background ratio and is chosen. During an incubation period of 10 min, Gal converts ?-D-galactopyranoside into p-aminophenol (AP), which is oxidized to p-quinone imine (QI) by KIO3. When -0.05 V vs. Ag/AgCl is applied to an immunosensing electrode, QI is reduced to AP, and the regenerated AP is then reoxidized by KIO3. The electroreduction-based EC redox cycling is induced. An indium-tin oxide electrode modified with reduced graphene oxide and an applied potential of -0.05 V are used to achieve low and reproducible background currents, slow O2 reduction, and fast electroreduction of QI. KIO3 favorably converts AA into noninterfering species during the incubation period. The detection limit for VV in commercial 50% mandarin juice (AA concentration = 0.7 mM) is 4 × 10(3) plaque-forming unit (PFU) per mL. The new EC redox cycling scheme is promising for sensitive detection of proteins, viruses, and bacteria in solutions containing high concentrations of AA. PMID:26149118

  17. Fabrication of GNPs/CDSH-Fc/nafion modified electrode for the detection of dopamine in the presence of ascorbic acid

    International Nuclear Information System (INIS)

    A novel dopamine sensor was fabricated by forming the inclusion complex between mono-6-thio-?-cyclodextrin (CD-SH) and ferrocene (Fc) functionalized gold nanoparticles (GNPs) films on a platinum electrode. The properties of the GNPs/CDSH-Fc nanocomposite were characterized by Fourier transform infrared spectra, UV-visible absorption spectroscopy, transmission electron microscopy and cyclic voltammetry. The electrochemistry of dopamine (DA) was investigated by cyclic voltammetry (CV) and differential pulse voltammograms (DPV). The electrooxidation of dopamine could be catalyzed by Fc/Fc+ couple as a mediator and had a higher electrochemical response due to the unique performance of GNPs/CDSH-Fc. The anodic peaks of DA and ascorbic acid (AA) in their mixture can be well separated by the prepared electrode. Under optimum conditions linear calibration graphs were obtained over the DA concentration range 2.0 x 10-6 to 5.0 x 10-5 M with a correlation coefficient of 0.998 and a detection limit of 9.0 x 10-8 M (S/N = 3). The modified electrode had been effectively applied for the assay of DA in dopamine hydrochloride injections. This work provides a simple and easy approach to selectively detect DA in the presence of AA. - Research highlights: ? The sensor of DA was constructed by using GNPs/CDSH-Fc as the building block. ? Inclusion complex on the surface of GNPs decreased the leakage of mediator. ? The electro-oxidation of DA could be catalyzed by Fc/Fc+ couple as a mediator. ? This work provides a simple approach to selectively detect DA in the presence of AA.

  18. Ascorbic Acid Reduces the Adverse Effects of Delayed Administration of Tissue Plasminogen Activator in a Rat Stroke Model.

    Science.gov (United States)

    Allahtavakoli, Mohammad; Amin, Fatemeh; Esmaeeli-Nadimi, Ali; Shamsizadeh, Ali; Kazemi-Arababadi, Mohammad; Kennedy, Derek

    2015-11-01

    Delayed treatment of stroke with recombinant tissue plasminogen activator (r-tPA) induces overexpression of matrix metalloproteinase 9 (MMP-9) which leads to breakdown of the blood-brain barrier (BBB) and causes more injuries to the brain parenchyma. In this study, the effect of ascorbic acid (AA), an antioxidant agent, on the delayed administration of r-tPA in a rat model of permanent middle cerebral artery occlusion (MCAO) was investigated. Forty male rats were randomly divided into four groups: untreated control rats (ischaemic animals), AA-treated (500 mg/kg; 5 hr after stroke) rats, r-tPA-treated (5 hr after stroke 1 mg/kg) rats and rats treated with the combination of AA and r-tPA. Middle cerebral artery occlusion was induced by occluding the right middle cerebral artery (MCA). Infarct size, BBB, brain oedema and the levels of MMP-9 were measured at the end of study. Neurological deficits were evaluated at 24 and 48 hr after stroke. Compared to the control or r-tPA-treated animals, AA alone (p control; p brain oedema (p control or the r-tPA-treated animals. Latency to the removal of sticky labels from the forepaw was also significantly decreased after the administration of AA + r-tPA (p < 0.05) at 24 or 48 hr after stroke. Based on our data, acute treatment with AA may be considered as a useful candidate to reduce the side effects of delayed application of r-tPA in stroke therapy. PMID:25899606

  19. Assessment of thermal load on transported goats administered with ascorbic acid during the hot-dry conditions

    Science.gov (United States)

    Minka, N. S.; Ayo, J. O.

    2012-03-01

    The major factor in the induction of physiological stress during road transportation of livestock is the complex fluctuations of the thermal transport microenvironment, encountered when animals are transported across different ecological zones. Recommended guidelines on optimum "on-board" conditions in which goats should be transported are lacking, and there are no acceptable ranges and limits for the thermal loads to which goats may be subjected during long-distance road transportation in hot-dry conditions. Panting score (PS), rectal temperature (RT), heart rate (HR) and respiratory rate (RR) were employed as reliable stress indices to assess the effects of different thermal loads, measured as temperature humidity index (THI), encountered in the vehicle during 12 h of road transportation of 40 goats, and to suggest the administration of 100 mg/kg body weight of ascorbic acid (AA) as an ameliorating agent. The results obtained showed that the PS, RT, HR and RR rose above normal reference values with increase in the THI and journey duration. The rise in PS value, which is a visual indicator of the severity of thermal load, was the most pronounced. The results suggest that values of THI in the vehicle up to 94.6 constitute no risk, while at of 100 it presents a moderate risk and above 100 may result in severe stress. The relationships between the thermal load and the physiological variables were positive and significant ( P body weight of AA before road transportation mitigated the risk of adverse effects of high THI values and other stress factors due to road transportation in goats.

  20. Combined effect of ascorbic acid and selenium supplementation on alcohol-induced oxidative stress in guinea pigs.

    Science.gov (United States)

    Sivaram, Asha G; Suresh, M V; Indira, M

    2003-03-01

    Oxidative stress is a key step in the pathogenesis of ethanol associated liver injury. Ethanol administration induces an increase in lipid peroxidation either by enhancing the production of oxygen reactive species or by decreasing the level of endogenous antioxidants. In this present study, four groups of male guinea pigs (Cavia porcellus) were maintained for 45 days as follows: Control group (1 mg ascorbic acid (AA)/100 g body wt./day); Ethanol group (1 mg AA/100 g body wt./day+900 mg ethanol/100 g body wt./day); Selenium+AA group (25 mg AA+0.05 mg sodium selenite/100 g body wt./day); Ethanol+Se+AA group (25 mg AA+0.05 mg sodium selenite/100 g body wt.+900 mg ethanol/100 g body wt./day). Malondialehyde (MDA), hydroperoxides (HP) and conjugated dienes (CD) were significantly increased, while the activities of scavenging enzymes superoxide dismutase (SOD) and catalase were reduced in the alcohol administered groups. Co-administration of Se+AA along with alcohol increased the activities of scavenging enzymes and reduced the lipid peroxidation products level in hepatic tissues of guinea pigs. Activities of glutathione peroxidase (GPX) and glutathione reductase (GR) were enhanced in co-administered group. gamma-Glutamyl transpeptidase (GGT), a marker enzyme of alcohol induced toxicity, was also reduced, as was the glutathione content. This study suggests that the combined effect of Se+AA, provides protection against alcohol-induced oxidative stress as evidenced from the decreased levels of lipid peroxidation products and enhanced activities of scavenging enzymes. PMID:12643986

  1. Simultaneous Electrochemical Detection of Dopamine and Ascorbic Acid Using an Iron Oxide/Reduced Graphene Oxide Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Teo Peik-See

    2014-08-01

    Full Text Available 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/rGO/GCE towards electrocatalytic oxidation of DA was investigated by cyclic voltammetry (CV and differential pulse voltammetry (DPV analysis. The electrochemical studies revealed that the Fe3O4/rGO/GCE dramatically increased the current response against the DA, due to the synergistic effect emerged between Fe3O4 and rGO. This implies that Fe3O4/rGO/GCE could exhibit excellent electrocatalytic activity and remarkable electron transfer kinetics towards the oxidation of DA. Moreover, the modified sensor electrode portrayed sensitivity and selectivity for simultaneous determination of AA and DA. The observed DPVs response linearly depends on AA and DA concentration in the range of 1–9 mM and 0.5–100 µM, with correlation coefficients of 0.995 and 0.996, respectively. The detection limit of (S/N = 3 was found to be 0.42 and 0.12 µM for AA and DA, respectively.

  2. Ascorbic acid delivered by mesoporous silica nanoparticles induces the differentiation of human embryonic stem cells into cardiomyocytes.

    Science.gov (United States)

    Ren, Mingming; Han, Zhen; Li, Jinglai; Feng, Gang; Ouyang, Shuyuan

    2015-11-01

    Embryonic stem (ES) cells offer the potential to generate all cell types in the body, which provide a promising approach to repair tissue damage or dysfunction. In the past decade, great efforts have been made to induce the differentiation of ES cells into numerous types of cells, such as adipocytes, neurocytes and cardiomyocytes. However, the low differentiated efficiency and successful rate limit the development of induction of the differentiation of stem cells for tissue engineering. Here, we utilize ascorbic acid (AA)-loaded fluorescent TRITC-mesoporous silica nanoparticles (TMSN-AA) as a potential tool to induce the differentiation of human ES cells into cardiomyocytes. The treatment of human ES cells by TMSN-AA nanoplex arrests cell cycle at G1 phase and decreases the expression of stemness genes octamer-binding transcription factor 4 (OCT4) and sex determining region Y-box 2 (SOX2), which exhibits more significant induction efficiency of stem cell differentiation than the treatment by AA alone. Furthermore, we have tested the myocardial marker genes cardiac Troponin I (cTnI) and fetal liver kinase 1 (FLK-1), and found these genes are up-regulated by TMSN-AA nanoplex. Importantly, this work demonstrates the more efficient induction efficiency of human ES cells differentiation by the nanoparticle-drug formulation. Our studies reveal a novel approach based on MSNs as nanocarriers to induce the differentiation of human ES cells into cardiomyocytes efficiently and feasibly, and offer the potential perspectives for tissue engineering, eventually in clinical applications. PMID:26249600

  3. Electropolymerization of brilliant cresyl blue on carbon ionic liquid electrode and electrocatalytic application for the voltammetric determination of ascorbic acid

    Scientific Electronic Library Online (English)

    Li, Xia; Qingjuan, Niu; Guangjiu, Li; Tianrong, Zhan; Wei, Sun.

    2011-03-01

    Full Text Available Azul de cresil brilhante (BCB) foi eletropolimerizado sobre a superfície de um eletrodo de carbono líquido iônico (CILE) por voltametria cíclica de varredura na faixa de potencial de -0,5 a 1,0 V. CILE foi preparado usando o 1-etil-3-metil-imidazólio tetrafluoroborato ([EMIM]BF4) como modificador. U [...] m filme polimerico estável de BCB foi obtido no CILE com aparecimento de um par de picos redox. As características do filme PBCB foram estudadas por diversos métodos tais como, microscopia eletrônica de varredura (SEM), espectroscopia de impedância eletroquímica (EIS) e voltametria cíclica. O eletrodo