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1

Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid.  

UK PubMed Central (United Kingdom)

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.

Lidong W; Yongliang M; Wendi Z; Qiangwei L; Yi Z; Zhanchao Z

2013-08-01

2

Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid.  

Science.gov (United States)

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

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

2013-04-18

3

Inhibiting effect of ascorbic acid on the growth of human mammary tumor xenografts.  

UK PubMed Central (United Kingdom)

The effect of ascorbic acid on the growth of a human mammary tumor in mice has been investigated using the 6-d subrenal capsule assay method. The results indicated that ascorbic acid administered in the drinking water significantly inhibited the growth of the tumor fragments implanted beneath the renal capsule of mice. Administration of a mixture of ascorbic acid and cupric sulfate orally or intraperitoneally significantly inhibited tumor growth in these mice, whereas neither alone was effective. These results support the hypothesis that certain oxidation or degradation products of ascorbic acid were active antineoplastic agents for the human mammary tumor studied. The activity of D-isoascorbic acid, an isomer of ascorbic acid, was similar to that of ascorbic acid. This suggests that the antitumor activity of ascorbic acid was not due to the metabolism of ascorbic acid as a vitamin, but due to its chemical properties.

Tsao CS

1991-12-01

4

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

UK PubMed Central (United Kingdom)

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.

Takebayashi J; Kaji H; Ichiyama K; Makino K; Gohda E; Yamamoto I; Tai A

2007-10-01

5

Inhibition of dimeric dihydrodiol dehydrogenases of rabbit and pig lens by ascorbic acid.  

UK PubMed Central (United Kingdom)

The dehydrogenase activity of dimeric dihydrodiol dehydrogenases (DD) purified from pig and rabbit lenses was inhibited by either L-ascorbic acid or its epimer, isoascorbic acid, at pH 7.5. Isoascorbate [IC50 (concn. giving 50% inhibition) = 0.043 mM for the pig enzyme; IC50 = 0.13 mM for the rabbit enzyme] was a more potent inhibitor than ascorbate (IC50 values 0.45 and 0.90 mM respectively), but 1 mM-dehydroascorbate gave less than 30% inhibition. Glucose, glucuronate, gulono-gamma-lactone, glutathione and dithiothreitol did not inhibit the enzyme activity. The inhibition by isoascorbate and ascorbate was instantaneous and reversible, and their inhibitory potency was decreased by addition of ascorbate oxidase. In the reverse reaction, isoascorbate and ascorbate gave low IC50 values of 0.013 and 0.10 mM respectively for the pig enzyme and 0.025 and 0.25 mM for the rabbit enzyme. The inhibition patterns by the two compounds were competitive with respect to dihydrodiols of naphthalene and benzene and uncompetitive with respect to NADP+, but those in the reverse reaction were uncompetitive with respect to both carbonyl substrate and NADPH. The steady-state kinetic measurements in the forward and reverse reactions by the pig enzyme were consistent with an ordered Bi Bi mechanism, in which NADP+ binds to the enzyme first and NADPH leaves last. The results indicate that ascorbate and its epimer directly bind to an enzyme: NADP+ binary complex as dead-end inhibitors. Thus ascorbate may be an important modulator of DD in the lens.

Hara A; Shinoda M; Kanazu T; Nakayama T; Deyashiki Y; Sawada H

1991-04-01

6

Inhibition of dimeric dihydrodiol dehydrogenases of rabbit and pig lens by ascorbic acid.  

Science.gov (United States)

The dehydrogenase activity of dimeric dihydrodiol dehydrogenases (DD) purified from pig and rabbit lenses was inhibited by either L-ascorbic acid or its epimer, isoascorbic acid, at pH 7.5. Isoascorbate [IC50 (concn. giving 50% inhibition) = 0.043 mM for the pig enzyme; IC50 = 0.13 mM for the rabbit enzyme] was a more potent inhibitor than ascorbate (IC50 values 0.45 and 0.90 mM respectively), but 1 mM-dehydroascorbate gave less than 30% inhibition. Glucose, glucuronate, gulono-gamma-lactone, glutathione and dithiothreitol did not inhibit the enzyme activity. The inhibition by isoascorbate and ascorbate was instantaneous and reversible, and their inhibitory potency was decreased by addition of ascorbate oxidase. In the reverse reaction, isoascorbate and ascorbate gave low IC50 values of 0.013 and 0.10 mM respectively for the pig enzyme and 0.025 and 0.25 mM for the rabbit enzyme. The inhibition patterns by the two compounds were competitive with respect to dihydrodiols of naphthalene and benzene and uncompetitive with respect to NADP+, but those in the reverse reaction were uncompetitive with respect to both carbonyl substrate and NADPH. The steady-state kinetic measurements in the forward and reverse reactions by the pig enzyme were consistent with an ordered Bi Bi mechanism, in which NADP+ binds to the enzyme first and NADPH leaves last. The results indicate that ascorbate and its epimer directly bind to an enzyme: NADP+ binary complex as dead-end inhibitors. Thus ascorbate may be an important modulator of DD in the lens.

Hara, A; Shinoda, M; Kanazu, T; Nakayama, T; Deyashiki, Y; Sawada, H

1991-01-01

7

Inhibition of bacterial multiplication by the iron chelator deferoxamine: potentiating effect of ascorbic acid.  

Science.gov (United States)

Since iron is essential for the multiplication of microorganisms, the effect of the iron chelator deferoxamine, with or without ascorbic acid, on the growth of 43 strains of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Alcaligenes faecalis, Neisseria meningitidis and species of Salmonella, Enterobacter, Pseudomonas and Providencia, was investigated with the use of an automated turbidimeter. Addition of deferoxamine (25-400 micrograms/ml) to the incubation medium was inhibitory in a dose-dependent fashion. At concentrations between 200-400 micrograms/ml, growth was about 25% lower than control values. However, when ascorbic acid (100 micrograms/ml) was added to the culture medium, this antimicrobial activity of deferoxamine was significantly increased to on average 75% of the control value (p less than 0.05). Ascorbic acid alone had no bacteriostatic properties. Growth in the presence of 200 micrograms/ml deferoxamine combined with 100 micrograms/ml ascorbic acid was significantly lower than that in control media without additions (p less than 0.001). Addition of ferric citrate to the culture medium at a concentration sufficient to saturate all of the deferoxamine with iron, abolished the growth inhibiting effect of deferoxamine. The results provide evidence that deferoxamine is bacteriostatic due to its capacity to deplete iron which would otherwise be used for bacterial multiplication, and that ascorbic acid enhances this antibacterial property of deferoxamine. PMID:6416837

van Asbeck, B S; Marcelis, J H; Marx, J J; Struyvenberg, A; van Kats, J H; Verhoef, J

1983-10-01

8

Inhibition of bacterial multiplication by the iron chelator deferoxamine: potentiating effect of ascorbic acid.  

UK PubMed Central (United Kingdom)

Since iron is essential for the multiplication of microorganisms, the effect of the iron chelator deferoxamine, with or without ascorbic acid, on the growth of 43 strains of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Alcaligenes faecalis, Neisseria meningitidis and species of Salmonella, Enterobacter, Pseudomonas and Providencia, was investigated with the use of an automated turbidimeter. Addition of deferoxamine (25-400 micrograms/ml) to the incubation medium was inhibitory in a dose-dependent fashion. At concentrations between 200-400 micrograms/ml, growth was about 25% lower than control values. However, when ascorbic acid (100 micrograms/ml) was added to the culture medium, this antimicrobial activity of deferoxamine was significantly increased to on average 75% of the control value (p less than 0.05). Ascorbic acid alone had no bacteriostatic properties. Growth in the presence of 200 micrograms/ml deferoxamine combined with 100 micrograms/ml ascorbic acid was significantly lower than that in control media without additions (p less than 0.001). Addition of ferric citrate to the culture medium at a concentration sufficient to saturate all of the deferoxamine with iron, abolished the growth inhibiting effect of deferoxamine. The results provide evidence that deferoxamine is bacteriostatic due to its capacity to deplete iron which would otherwise be used for bacterial multiplication, and that ascorbic acid enhances this antibacterial property of deferoxamine.

van Asbeck BS; Marcelis JH; Marx JJ; Struyvenberg A; van Kats JH; Verhoef J

1983-10-01

9

INHIBITION OF ASCORBIC ACID ELECTROOXIDATION ON GOLD BY OVEROXIDIZED POLYPYRROL  

Directory of Open Access Journals (Sweden)

Full Text Available Electroanalytical determination of neurotransmitters in the brain, presents the difficulty of high anion ascorbate concentration, which oxidized at almost the same potential as the neurotransmitters. To avoid this interference, the electrode is recovered with a selective overoxidized polypyrrol (Ppy) film, which supresses voltammetric ascorbate wave and the discharge current of neurotransmitter is only observed. The Pyrrol polymerization is made with a stepped voltammetric sweep, between 0.3 V and an anodic potential of approximately 1.0 V in a buffer solution at 0,005 V/sec. With potentiostatic electrolysis at 1.05 V (measured vs. reversible hydrogen electrode, RHE) the polymer film is oxidized and it is overoxidized at 1.7 V. During 48 hours, the film remains stable. Then, it slowly losses its properties. The optimum conditions to obtain a good quality film are found in this research.

Luis Pesetti; Clidia R. Abaca; Claudio Falivene; Jorge O. Zerbino; María G. Sustersic

2013-01-01

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Comparative brain cholinesterase-inhibiting activity of Glycyrrhiza glabra, Myristica fragrans, ascorbic acid, and metrifonate in mice.  

UK PubMed Central (United Kingdom)

The central cholinergic pathways play a prominent role in the learning and memory processes. Acetylcholinesterase is an enzyme that inactivates acetylcholine. The present study was undertaken to estimate the acetylcholinesterase- inhibiting activity of extracts of Glycyrrhiza glabra, Myristica fragrans seeds, and ascorbic acid and compare these values with a standard acetylcholinesterase-inhibiting drug, metrifonate. Aqueous extract of G. glabra (150 mg/kg p.o. for 7 successive days), n-hexane extract of M. fragrans seeds (5 mg/kg p.o. for 3 successive days), ascorbic acid (60 mg/kg i.p. for 3 successive days), and metrifonate (50 mg/kg i.p.) were administered to young male Swiss albino mice. Acetylcholinesterase enzyme was estimated in brains of mice. G. glabra, M. fragrans, ascorbic acid, and metrifonate significantly decreased acetylcholinesterase activity as compared with their respective vehicle-treated control groups.

Dhingra D; Parle M; Kulkarni SK

2006-01-01

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Comparative brain cholinesterase-inhibiting activity of Glycyrrhiza glabra, Myristica fragrans, ascorbic acid, and metrifonate in mice.  

Science.gov (United States)

The central cholinergic pathways play a prominent role in the learning and memory processes. Acetylcholinesterase is an enzyme that inactivates acetylcholine. The present study was undertaken to estimate the acetylcholinesterase- inhibiting activity of extracts of Glycyrrhiza glabra, Myristica fragrans seeds, and ascorbic acid and compare these values with a standard acetylcholinesterase-inhibiting drug, metrifonate. Aqueous extract of G. glabra (150 mg/kg p.o. for 7 successive days), n-hexane extract of M. fragrans seeds (5 mg/kg p.o. for 3 successive days), ascorbic acid (60 mg/kg i.p. for 3 successive days), and metrifonate (50 mg/kg i.p.) were administered to young male Swiss albino mice. Acetylcholinesterase enzyme was estimated in brains of mice. G. glabra, M. fragrans, ascorbic acid, and metrifonate significantly decreased acetylcholinesterase activity as compared with their respective vehicle-treated control groups. PMID:16822217

Dhingra, Dinesh; Parle, Milind; Kulkarni, S K

2006-01-01

12

ASCORBIC ACID MODULATES SPONTANEOUS THYMOCYTE APOPTOSIS  

Directory of Open Access Journals (Sweden)

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

Voja Pavlovi?; Snežana Ceki?; Vladmila Bojani?; Nenad Stojiljkovi?; Goran Rankovi?

2005-01-01

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Ascorbic acid transport into cultured pituitary cells  

Energy Technology Data Exchange (ETDEWEB)

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

Cullen, E.I.; May, V.; Eipper, R.A.

1986-05-01

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Ascorbic acid transport into cultured pituitary cells  

International Nuclear Information System (INIS)

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

1986-01-01

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COSMETIC COMPOSITION CONTAINING ASCORBIC ACID-2-GLUCOSIDE  

UK PubMed Central (United Kingdom)

PURPOSE: Provided is a cosmetic composition containing ascorbic acid-2-glucoside of ascorbic acid derivatives. The ascorbic acid-2-glucoside inhibits the formation of melanin, promotes the synthesis of collagen, lightens the color of existing melanin, inhibits skin inflammation caused by ultraviolet rays and the formation of free radicals. Therefore, the cosmetic composition is used for skin whitening. CONSTITUTION: A skin whitening cosmetic composition is characterized by containing 0.001-10 wt.% of ascorbic acid-2-glucoside as a skin whitening agent. It is formulated into emulsion, essence, eye-cream, nourishing cream, eye-essence, toilet-water, facial pack, body cream and the like.

CHO GUK YEONG

16

Ascorbic acid inhibits replication and infectivity of avian RNA tumor virus  

Energy Technology Data Exchange (ETDEWEB)

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

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

1980-04-01

17

Relationship between ascorbic acid and cell division.  

UK PubMed Central (United Kingdom)

Proliferating cells require large amounts of ascorbic acid to reach cell division. The decrease in ascorbic acid caused by adding lycorine, an inhibitor of ascorbic acid biosynthesis, induces profound inhibition of cell division: the cell cycle is arrested in G1 and G2 phase, more than 90% of the cells being accumulated in G1 after some time. The effect of lycorine on mitotic index (MI) has been reversed by increasing experimentally the concentration of ascorbic acid in tissues. Ascorbic acid control on cell division is found to be specific, since isoascorbic acid is wholly ineffective. It is suggested that the principal role of ascorbic acid in the cell cycle may be related to its action in controlling the synthesis of hydroxyproline-containing proteins, which can be essential requirements for development of G1 and G2.

Liso R; Calabrese G; Bitonti MB; Arrigoni O

1984-02-01

18

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.

2002-01-01

19

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

Directory of Open Access Journals (Sweden)

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

Weerayuth SUTTIRAK; Supranee MANURAKCHINAKORN

2010-01-01

20

Ascorbic acid stability in aqueous solutions.  

UK PubMed Central (United Kingdom)

Different water purity provokes a great variation of the stability of ascorbic acid and isoascorbic acid solutions. The effect of temperature on ascorbate aerobic oxidation was assessed by means of Arrhenius plots from which thermodynamic parameters were derived. The presence of bovine serum albumin drastically reduces the vitamin oxidation rate regardless of stereoisomerism. On the other hand the interaction with alkaline phosphatase, an enzyme inhibited by preincubation with vitamin C, does not modify significantly the stability in the experimental conditions used.

Meucci E; Martorana GE; Ursitti A; Pischiutta MG; Miggiano GA; Castelli A

1985-01-01

 
 
 
 
21

Ascorbate inhibition of 6-aminonicotinamide teratogenesis in chicken embryos.  

UK PubMed Central (United Kingdom)

Chicken eggs of 4 or 6 days of incubation were injected with 10 mug 6-aminonicotinamide (6-AN) or 6-AN plus various doses of sodium ascorbate, calcium ascorbate, or ascorbic acid; 11-day embryos were examined grossly and histologically. 6-AN-treated embryos had various degrees of micromelia and were reduced in overall size. All three ascorbates inhibited 6-AN teratogenesis but not completely. The extent of inhibition was dose related. Increased amounts of intercellular matrix and decreased necrosis of chondrocytes in the limb cartilage of protected embryos correlated with the gross findings.

Overman DO; Graham MN; Roy WA

1976-02-01

22

Kinetic determination of ascorbic acid in pharmaceuticalsamples  

Directory of Open Access Journals (Sweden)

Full Text Available A kinetic method is described for the determination of ascorbic acid based on its inhibiting effect on the Mn(II) catalysis of the oxidation of Malachite Green with potassium periodate. The sensitivity of the method is 35.4 ng cm-3. The relative error ranges between 2.66 and 7.45% for the concentration interval 35.4 to 354 ng cm-3. Kinetic equations are proposed for the investigated process. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The method was applied for the determination of ascorbic acid in pharmaceutical samples.

S. S. MITIC; G. Z. MILETIC; S. M. MILETIC; D. A. KOSTIC

1999-01-01

23

Uncoupling of incorporation of ascorbic acid and apoptosis induction.  

Science.gov (United States)

Exposure of human promyelocytic leukemic HL-60 cells to millimolar concentration of sodium ascorbate induced apoptotic cell death. The extent of apoptosis induction was a positive function of temperature at the time of exposure. The incorporation of [1-14C] ascorbic acid into the cytosolic fraction of HL-60 cells was also temperature-dependent, and competitively inhibited by active analogs (L-ascorbic acid, sodium L-ascorbate, D-isoascorbic acid, sodium 6-beta-O-galactosyl-L-ascorbate, sodium 5,6-benzylidene-L-ascorbate), but not by inactive analogs (L-ascorbic acid-2-phosphate magnesium, L-ascorbic acid 2-sulfate). Calcium depletion, which had considerably reduced the apoptosis-inducing activity of sodium ascorbate, did not affect the intracellular incorporation of [14C] ascorbic acid. These data suggests that cell death might not be simply induced by the intracellular incorporation of ascorbate, but rather initiated by the rapid elevation of intracellular Ca2+ concentration, possibly mediated by an as yet unidentified temperature-sensitive mechanism. PMID:9703900

Amano, Y; Sakagami, H; Tanaka, T; Yamanaka, Y; Nishimoto, Y; Yamaguchi, M; Takeda, M

24

Uncoupling of incorporation of ascorbic acid and apoptosis induction.  

UK PubMed Central (United Kingdom)

Exposure of human promyelocytic leukemic HL-60 cells to millimolar concentration of sodium ascorbate induced apoptotic cell death. The extent of apoptosis induction was a positive function of temperature at the time of exposure. The incorporation of [1-14C] ascorbic acid into the cytosolic fraction of HL-60 cells was also temperature-dependent, and competitively inhibited by active analogs (L-ascorbic acid, sodium L-ascorbate, D-isoascorbic acid, sodium 6-beta-O-galactosyl-L-ascorbate, sodium 5,6-benzylidene-L-ascorbate), but not by inactive analogs (L-ascorbic acid-2-phosphate magnesium, L-ascorbic acid 2-sulfate). Calcium depletion, which had considerably reduced the apoptosis-inducing activity of sodium ascorbate, did not affect the intracellular incorporation of [14C] ascorbic acid. These data suggests that cell death might not be simply induced by the intracellular incorporation of ascorbate, but rather initiated by the rapid elevation of intracellular Ca2+ concentration, possibly mediated by an as yet unidentified temperature-sensitive mechanism.

Amano Y; Sakagami H; Tanaka T; Yamanaka Y; Nishimoto Y; Yamaguchi M; Takeda M

1998-07-01

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Final report of the safety assessment of L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate as used in cosmetics.  

Science.gov (United States)

L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate function in cosmetic formulations primarily as antioxidants. Ascorbic Acid is commonly called Vitamin C. Ascorbic Acid is used as an antioxidant and pH adjuster in a large variety of cosmetic formulations, over 3/4 of which were hair dyes and colors at concentrations between 0.3% and 0.6%. For other uses, the reported concentrations were either very low (Magnesium Ascorbyl Phosphate functions as an antioxidant in cosmetics and was reported being used at concentrations from 0.001% to 3%. Sodium Ascorbate also functions as an antioxidant in cosmetics at concentrations from 0.0003% to 0.3%. Related ingredients (Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate) have been previously reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel and found "to be safe for use as cosmetic ingredients in the present practices of good use." Ascorbic Acid is a generally recognized as safe (GRAS) substance for use as a chemical preservative in foods and as a nutrient and/or dietary supplement. Calcium Ascorbate and Sodium Ascorbate are listed as GRAS substances for use as chemical preservatives. L-Ascorbic Acid is readily and reversibly oxidized to L-dehydroascorbic acid and both forms exist in equilibrium in the body. Permeation rates of Ascorbic Acid through whole and stripped mouse skin were 3.43 +/- 0.74 microg/cm(2)/h and 33.2 +/- 5.2 microg/cm(2)/h. Acute oral and parenteral studies in mice, rats, rabbits, guinea pigs, dogs, and cats demonstrated little toxicity. Ascorbic Acid and Sodium Ascorbate acted as a nitrosation inhibitor in several food and cosmetic product studies. No compound-related clinical signs or gross or microscopic pathological effects were observed in either mice, rats, or guinea pigs in short-term studies. Male guinea pigs fed a control basal diet and given up to 250 mg Ascorbic Acid orally for 20 weeks had similar hemoglobin, blood glucose, serum iron, liver iron, and liver glycogen levels compared to control values. Male and female F344/N rats and B6C3F(1) mice were fed diets containing up to 100,000 ppm Ascorbic Acid for 13 weeks with little toxicity. Chronic Ascorbic Acid feeding studies showed toxic effects at dosages above 25 mg/kg body weight (bw) in rats and guinea pigs. Groups of male and female rats given daily doses up to 2000 mg/kg bw Ascorbic Acid for 2 years had no macro- or microscopically detectable toxic lesions. Mice given Ascorbic Acid subcutaneous and intravenous daily doses (500 to 1000 mg/kg bw) for 7 days had no changes in appetite, weight gain, and general behavior; and histological examination of various organs showed no changes. Ascorbic Acid was a photoprotectant when applied to mice and pig skin before exposure to ultraviolet (UV) radiation. The inhibition of UV-induced suppression of contact hypersensitivity was also noted. Magnesium Ascorbyl Phosphate administration immediately after exposure in hairless mice significantly delayed skin tumor formation and hyperplasia induced by chronic exposure to UV radiation. Pregnant mice and rats were given daily oral doses of Ascorbic Acid up to 1000 mg/kg bw with no indications of adult-toxic, teratogenic, or fetotoxic effects. Ascorbic Acid and Sodium Ascorbate were not genotoxic in several bacterial and mammalian test systems, consistent with the antioxidant properties of these chemicals. In the presence of certain enzyme systems or metal ions, evidence of genotoxicity was seen. The National Toxicology Program (NTP) conducted a 2-year oral carcinogenesis bioassay of Ascorbic Acid (25,000 and 50,000 ppm) in F344/N ra

Elmore, Amy R

2005-01-01

26

Mitochondrial recycling of ascorbic acid as a mechanism for regenerating cellular ascorbate.  

UK PubMed Central (United Kingdom)

Mitochondria are the major source of potentially damaging reactive oxygen species in most cells. Since ascorbic acid, or vitamin C, can protect against cellular oxidant stress, we studied the ability of mitochondria prepared from guinea pig skeletal muscle to recycle the vitamin from its oxidized forms. Although ascorbate concentrations in freshly prepared mitochondria were only about 0.2 mM, when provided with 6 mM succinate and 1 mM dehydroascorbate (the two-electron-oxidized form of the vitamin), mitochondria were able to generate and maintain concentrations as high as 4 mM, while releasing most of the ascorbate into the incubation medium. Mitochondrial reduction of dehydroascorbate was strongly inhibited by 1,3-bis(chloroethyl)-1-nitrosourea and by phenylarsine oxide. Despite existing evidence that mitochondrial ascorbate protects the organelle from oxidant damage, ascorbate failed to preserve mitochondrial alpha-tocopherol during prolonged incubation in oxygenated buffer. Nonetheless, the capacity for mitochondria to recycle ascorbate from its oxidized forms, measured as ascorbate-dependent ferricyanide reduction, was several-fold greater than total steady-state ascorbate concentrations. This, and the finding that more than half of the ascorbate recycled from dehydroascorbate escaped the mitochondrion, suggests that mitochondrial recycling of ascorbate might be an important mechanism for regenerating intracellular ascorbate.

May JM; Li L; Qu ZC; Cobb CE

2007-01-01

27

Ascorbic acid regeneration in chromaffin granules. In situ kinetics.  

UK PubMed Central (United Kingdom)

We have investigated in intact chromaffin secretory vesicles the kinetics, specificity, and mechanism of intragranular ascorbic acid regeneration by extragranular ascorbic acid. The apparent Km of internal ascorbic acid regeneration for external ascorbic acid was 280 microM by Lineweaver-Burk analysis and 287 microM by Eadie-Hofstee analysis. Intragranular ascorbic acid regeneration was specifically mediated by extragranular ascorbic acid or its isomer isoascorbic acid; the reducing agents glutathione, thiourea, homocysteine, NADH, and NADPH did not support regeneration. The structural analog D-glucose did not inhibit regeneration by external ascorbic acid, suggesting specificity at the membrane site of electron transfer. The driving force for regeneration of intragranular ascorbic acid was independent of membrane potential, absolute intragranular and extragranular pH, and ATPase activity, but might be coupled to the pH difference across the chromaffin granule membrane. Since the apparent Km of regeneration was approximately 10-fold below the cytosolic concentration of ascorbic acid, the reaction may proceed at Vmax in situ.

Dhariwal KR; Shirvan M; Levine M

1991-03-01

28

Degradation of Ascorbic Acid in Aqueous Solution  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An HPLC method, for the simultaneous determination of the degradation products of ascorbic acid, was employed to investigate the degradation of ascorbic acid in aqueous solution at different pH values. After ascorbic acid aqueous solutions were heated at 100 °C for 2 h, four main degradation product...

Yuan, JP; Chen, F

29

Ascorbic acid-based inhibitors of alpha-amylases.  

Science.gov (United States)

A series of ascorbic acid and isoascorbic acid derivatives has been evaluated as inhibitors of malt, bacterial, fungal, pancreatic and salivary alpha-amylases using a simple and quick assay procedure. The results demonstrate that the enediol moiety of ascorbic acid is essential for alpha-amylase inhibition. Acylation of the primary and secondary alcohols, and the absolute configuration of the secondary alcohol, do not affect the potency of inhibition. PMID:9873419

Abell, A D; Ratcliffe, M J; Gerrard, J

1998-07-01

30

Ascorbic acid-based inhibitors of alpha-amylases.  

UK PubMed Central (United Kingdom)

A series of ascorbic acid and isoascorbic acid derivatives has been evaluated as inhibitors of malt, bacterial, fungal, pancreatic and salivary alpha-amylases using a simple and quick assay procedure. The results demonstrate that the enediol moiety of ascorbic acid is essential for alpha-amylase inhibition. Acylation of the primary and secondary alcohols, and the absolute configuration of the secondary alcohol, do not affect the potency of inhibition.

Abell AD; Ratcliffe MJ; Gerrard J

1998-07-01

31

Role of ascorbic acid in the inhibition of polyphenol oxidase and the prevention of browning in different browning?sensitive Lactuca sativa var. capitata (L.) and Eruca sativa (Mill.) stored as fresh?cut produce  

UK PubMed Central (United Kingdom)

BACKGROUND: Polyphenol oxidase (PPO) and, to a minor extent, peroxidase (POD) represent the key enzymes involved in enzymatic browning, a negative process induced by cutting fresh?cut produce such as lettuce (Lactuca sativa) and rocket salad (Eruca sativa). Although ascorbic acid is frequently utilised as an anti?browning agent, its mechanism in the prevention of the browning phenomenon is not clearly understood. RESULTS: The activity of PPO and POD and their isoforms in lettuce (a high?browning and low?ascorbic acid species) and rocket salad (a low?browning and high?ascorbic species) was characterised. The kinetic parameters of PPO and in vitro ascorbic acid–PPO inhibition were also investigated. In rocket salad, PPO activity was much lower than that in lettuce and cutting induced an increase in PPO activity only in lettuce. Exogenous ascorbic acid (5?mmol?L?¹) reduced PPO activity by about 90% in lettuce. POD did not appear to be closely related to browning in lettuce. CONCLUSION: PPO is the main enzyme involved in the browning phenomenon; POD appears to play a minor role. The concentration of endogenous ascorbic acid in rocket salad was related to its low?browning sensitivity after cutting. In lettuce, the addition of ascorbic acid directly inhibited PPO activity. The results suggest that the high ascorbic acid content found in rocket salad plays an effective role in reducing PPO activity. © 2012 Society of Chemical Industry

Landi M; Degl'Innocenti E; Guglielminetti L; Guidi L

2013-06-01

32

Kinetic properties of light-dependent ascorbic acid oxidation by melanin.  

Science.gov (United States)

The kinetic properties of ascorbic acid oxidation by light-activated melanin granules demonstrate the presence of a specific reactive site on the melanin granule saturable by ascorbic acid. Increased light intensity increased the Vmax and reduced the Km of this reaction, indicating increased affinity of the active site for ascorbic acid. The kinetics of this reaction are not markedly changed in a reduced-oxygen environment. Ascorbic acid oxidation is competitively inhibited by isoascorbic acid, an epimer of ascorbic acid, while other tested reducing agents are inactive. The Ki for isoascorbic acid is 1 mM, about the same as the Km of ascorbic acid. PMID:8225027

Glickman, R D; Sowell, R; Lam, K W

1993-10-01

33

Kinetic properties of light-dependent ascorbic acid oxidation by melanin.  

UK PubMed Central (United Kingdom)

The kinetic properties of ascorbic acid oxidation by light-activated melanin granules demonstrate the presence of a specific reactive site on the melanin granule saturable by ascorbic acid. Increased light intensity increased the Vmax and reduced the Km of this reaction, indicating increased affinity of the active site for ascorbic acid. The kinetics of this reaction are not markedly changed in a reduced-oxygen environment. Ascorbic acid oxidation is competitively inhibited by isoascorbic acid, an epimer of ascorbic acid, while other tested reducing agents are inactive. The Ki for isoascorbic acid is 1 mM, about the same as the Km of ascorbic acid.

Glickman RD; Sowell R; Lam KW

1993-10-01

34

Regeneration of ascorbic acid by rat colon.  

UK PubMed Central (United Kingdom)

Plants and animals alike use ascorbic acid in a variety of reactions that result in net generation of dehydro-L-ascorbic acid. The ability to reduce dehydro-L-ascorbic acid back to ascorbic acid would conserve "total ascorbate" and would help to maintain the toxic oxidized form of the molecule at a low level. This study evaluated the rate of dehydro-L-ascorbic acid reduction either by following the rate of NADPH consumption or by analysis of the amount of 14C-labeled dehydro-L-ascorbic acid converted to ascorbic acid. A large percentage of the NADPH consumed by a semipurified preparation of rat colonic mucosa in vitro was dependent on the presence of dehydro-L-ascorbic acid. The tissue factor active in regenerating ascorbic acid is intermediate in size between cytochrome c and blue dextran. The present results indicate that the mucosa reduced dehydro-L-ascorbic acid by a cytosolic enzyme that uses NADPH as a hydrogen donor. Subsequent to precipitation by ammonium sulfate, the 55-70% fraction contains most of the reductase activity while consisting of only 17% of the cellular soluble protein.

Choi JL; Rose RC

1989-04-01

35

Characterization of alkaline phosphatase inactivation by ascorbic acid.  

UK PubMed Central (United Kingdom)

Ascorbic acid, isoascorbic acid and dehydroascorbic acid inhibit bovine kidney alkaline phosphatase activity. Ascorbic acid free radicals seem not to be involved. Dialysis does not make the inactivation reversible. A competitive mechanism can be inferred from experiments with phosphate and substrates, which block the activity decay. The influence of temperature, pH, other inhibitors and tertiary structure modifications on the inactivation process is also investigated.

Miggiano GA; Mordente A; Martorana GE; Meucci E; Castelli A

1984-09-01

36

Characterization of ascorbic acid uptake by isolated rat kidney cells.  

UK PubMed Central (United Kingdom)

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

Bowers-Komro DM; McCormick DB

1991-01-01

37

Characterization of ascorbic acid uptake by isolated rat kidney cells  

International Nuclear Information System (INIS)

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

1991-01-01

38

Characterization of ascorbic acid uptake by isolated rat kidney cells  

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-01-01

39

Regeneration of ascorbic acid in human placenta  

International Nuclear Information System (INIS)

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

1990-02-26

40

Regeneration of ascorbic acid in human placenta  

Energy Technology Data Exchange (ETDEWEB)

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

Rose, R.C.; Bode, A.M. (Univ. of North Dakota, Grand Forks (United States))

1990-02-26

 
 
 
 
41

Ascorbic acid in the human stomach.  

UK PubMed Central (United Kingdom)

Ascorbic acid, the reduced form of vitamin C, may protect against gastric cancer. Accordingly, this study assessed the variability of ascorbic acid and vitamin C in the gastric juice of 77 patients with dyspepsia. There was a vitamin C concentration gradient from gastric juice down to plasma in subjects with normal gastric mucosa, but not in those with chronic gastritis. Patients with chronic gastritis had significantly lower gastric concentrations of vitamin C and ascorbic acid, and ascorbic acid concentrations were especially low in subjects with hypochlorhydria. The presence of the concentration gradient suggests that a mechanism for the secretion of vitamin C into the stomach exists. This is compromised by chronic gastritis. The very low ascorbic acid concentrations in hypochlorhydria may be a consequence of oxidation by bacterial nitrite. Those patients who by the Correa model are at greatest risk for gastric cancer have the lowest gastric levels of ascorbic acid.

Sobala GM; Schorah CJ; Sanderson M; Dixon MF; Tompkins DS; Godwin P; Axon AT

1989-08-01

42

Ascorbic acid modulates pathogenecity markers of Candida albicans  

Directory of Open Access Journals (Sweden)

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

Ojha R.; Manzoor N.; Khan L.A.

2009-01-01

43

Aqeous solution of ascorbic acid  

UK PubMed Central (United Kingdom)

Aqueous solution useful as an additive to e.g. skin and hair care products, foodstuffs, bacterial or algae cultures, comprises excess emulsifier with specific hydrophilic-lipophilic balance value range Aqueous solution comprises excess emulsifier, e.g. Polysorbate with a hydrophilic-lipophilic balance (HLB) value of 9-18. An Independent claim is also included for a method of manufacturing the solution comprising: (1) adding Polysorbate to an aqueous ascorbic acid solution; and (2) stirring and heating mixture until it becomes clear.

Behnam Dariush

44

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

DEFF Research Database (Denmark)

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

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

2001-01-01

45

Ascorbic acid: effects on ricin intoxicated HeLa cells  

International Nuclear Information System (INIS)

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

1977-01-01

46

Final report of the safety assessment of L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate as used in cosmetics.  

UK PubMed Central (United Kingdom)

L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate function in cosmetic formulations primarily as antioxidants. Ascorbic Acid is commonly called Vitamin C. Ascorbic Acid is used as an antioxidant and pH adjuster in a large variety of cosmetic formulations, over 3/4 of which were hair dyes and colors at concentrations between 0.3% and 0.6%. For other uses, the reported concentrations were either very low (<0.01%) or in the 5% to 10% range. Calcium Ascorbate and Magnesium Ascorbate are described as antioxidants and skin conditioning agents--miscellaneous for use in cosmetics, but are not currently used. Sodium Ascorbyl Phosphate functions as an antioxidant in cosmetic products and is used at concentrations ranging from 0.01% to 3%. Magnesium Ascorbyl Phosphate functions as an antioxidant in cosmetics and was reported being used at concentrations from 0.001% to 3%. Sodium Ascorbate also functions as an antioxidant in cosmetics at concentrations from 0.0003% to 0.3%. Related ingredients (Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate) have been previously reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel and found "to be safe for use as cosmetic ingredients in the present practices of good use." Ascorbic Acid is a generally recognized as safe (GRAS) substance for use as a chemical preservative in foods and as a nutrient and/or dietary supplement. Calcium Ascorbate and Sodium Ascorbate are listed as GRAS substances for use as chemical preservatives. L-Ascorbic Acid is readily and reversibly oxidized to L-dehydroascorbic acid and both forms exist in equilibrium in the body. Permeation rates of Ascorbic Acid through whole and stripped mouse skin were 3.43 +/- 0.74 microg/cm(2)/h and 33.2 +/- 5.2 microg/cm(2)/h. Acute oral and parenteral studies in mice, rats, rabbits, guinea pigs, dogs, and cats demonstrated little toxicity. Ascorbic Acid and Sodium Ascorbate acted as a nitrosation inhibitor in several food and cosmetic product studies. No compound-related clinical signs or gross or microscopic pathological effects were observed in either mice, rats, or guinea pigs in short-term studies. Male guinea pigs fed a control basal diet and given up to 250 mg Ascorbic Acid orally for 20 weeks had similar hemoglobin, blood glucose, serum iron, liver iron, and liver glycogen levels compared to control values. Male and female F344/N rats and B6C3F(1) mice were fed diets containing up to 100,000 ppm Ascorbic Acid for 13 weeks with little toxicity. Chronic Ascorbic Acid feeding studies showed toxic effects at dosages above 25 mg/kg body weight (bw) in rats and guinea pigs. Groups of male and female rats given daily doses up to 2000 mg/kg bw Ascorbic Acid for 2 years had no macro- or microscopically detectable toxic lesions. Mice given Ascorbic Acid subcutaneous and intravenous daily doses (500 to 1000 mg/kg bw) for 7 days had no changes in appetite, weight gain, and general behavior; and histological examination of various organs showed no changes. Ascorbic Acid was a photoprotectant when applied to mice and pig skin before exposure to ultraviolet (UV) radiation. The inhibition of UV-induced suppression of contact hypersensitivity was also noted. Magnesium Ascorbyl Phosphate administration immediately after exposure in hairless mice significantly delayed skin tumor formation and hyperplasia induced by chronic exposure to UV radiation. Pregnant mice and rats were given daily oral doses of Ascorbic Acid up to 1000 mg/kg bw with no indications of adult-toxic, teratogenic, or fetotoxic effects. Ascorbic Acid and Sodium Ascorbate were not genotoxic in several bacterial and mammalian test systems, consistent with the antioxidant properties of these chemicals. In the presence of certain enzyme systems or metal ions, evidence of genotoxicity was seen. The National Toxicology Program (NTP) conducted a 2-year oral carcinogenesis bioassay of Ascorbic Acid (25,000 and 50,000 ppm) in F344/N ra

Elmore AR

2005-01-01

47

Interaction of erythorbic acid with ascorbic acid catabolism.  

UK PubMed Central (United Kingdom)

There exist altogether four stereoisomers of ascorbic acid. Erythorbic acid (D-isoascorbic acid) differs in the spatial configuration at carbon 5 and has less than 5 per cent of biological vitamin C activity. In guinea pigs, depending on an exogenous supply of ascorbic acid, a possible interaction of erythorbic acid with absorption, transport through the cell membranes at the tissue level, or with catabolism of ascorbic acid has been investigated. After oral administration, results suggest no difference in absorption of these two compounds from the intestine, whereas uptake by the tissues was approximately four to one in favour of ascorbic acid. Feeding experiments with erythorbic acid indicate the availability of ascorbic acid being diminished by 40-60% when administered together with erythorbic acid. Kinetic data on the catabolism of ascorbic acid showed a significant reduction in half-life (50% of the dose excreted) of the vitamin caused by administration of erythorbic acid. The results suggest the oxidative destruction of ascorbic acid in the liver being significantly accelerated. Thus, ingestion of erythorbic acid interacts with newly introduced ascorbic acid by enforcing the breakdown of ascorbic acid. Implications of these findings for the metabolism, availability and nutritional status of ascorbic acid in humans will be discussed.

Hornig D

1977-01-01

48

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

UK PubMed Central (United Kingdom)

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.

Ansar S; Iqbal M

2013-07-01

49

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.

1989-01-01

50

Ascorbic Acid, Biological Function and Chemistry.  

Science.gov (United States)

This is a report on the concluding year of a study in depth on the chemistry and metabolism of ascorbic acid and isoascorbic acid or erythorbic acid. The broad objectives of the research were to study in detail the biochemistry of these compounds to provi...

B. M. Tolbert

1978-01-01

51

Enterococcus faecalis grows on ascorbic acid.  

UK PubMed Central (United Kingdom)

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

Mehmeti I; Solheim M; Nes IF; Holo H

2013-08-01

52

Arsenic trioxide and ascorbic acid demonstrate promising activity against primary human CLL cells in vitro.  

UK PubMed Central (United Kingdom)

The compromised antioxidant defense system in chronic lymphocytic leukemia (CLL) suggested a potential use for reactive oxygen species (ROS) generating arsenic trioxide (ATO) and ascorbic acid. While both ATO and ascorbic acid mediate cytotoxicity in CLL B cells as single agents, the efficacy of ATO is enhanced by ascorbic acid. This effect is dependent on increased ROS accumulation, as pretreatment of B-CLL cells with a glutathione reducing buthionine sulfoximine or catalase inhibiting aminotriazole, enhanced ATO/ascorbic acid-mediated cytotoxicity. Pretreatment with reducing agents such as catalase, or thiol antioxidant, N-acetyl cysteine or GSH also abrogated ATO/ascorbic acid-mediated cytotoxicity. Furthermore, Hu1D10-mediated cell death was enhanced with ATO and ascorbic acid, thus justifying potential combination of ATO/arsenic trioxide therapy with antibodies such as Hu1D10 that also cause accumulation of ROS.

Biswas S; Zhao X; Mone AP; Mo X; Vargo M; Jarjoura D; Byrd JC; Muthusamy N

2010-07-01

53

Arsenic trioxide and ascorbic acid demonstrate promising activity against primary human CLL cells in vitro.  

Science.gov (United States)

The compromised antioxidant defense system in chronic lymphocytic leukemia (CLL) suggested a potential use for reactive oxygen species (ROS) generating arsenic trioxide (ATO) and ascorbic acid. While both ATO and ascorbic acid mediate cytotoxicity in CLL B cells as single agents, the efficacy of ATO is enhanced by ascorbic acid. This effect is dependent on increased ROS accumulation, as pretreatment of B-CLL cells with a glutathione reducing buthionine sulfoximine or catalase inhibiting aminotriazole, enhanced ATO/ascorbic acid-mediated cytotoxicity. Pretreatment with reducing agents such as catalase, or thiol antioxidant, N-acetyl cysteine or GSH also abrogated ATO/ascorbic acid-mediated cytotoxicity. Furthermore, Hu1D10-mediated cell death was enhanced with ATO and ascorbic acid, thus justifying potential combination of ATO/arsenic trioxide therapy with antibodies such as Hu1D10 that also cause accumulation of ROS. PMID:20171736

Biswas, Sabyasachi; Zhao, Xiaobin; Mone, Andrew P; Mo, Xiaokui; Vargo, Melissa; Jarjoura, David; Byrd, John C; Muthusamy, Natarajan

2010-02-19

54

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

Science.gov (United States)

This study explores the link between the antiproliferative activity of emodin through the generation of reactive oxygen species (ROS) in various cancer cell lines and the expression of the androgen receptor (AR) in the prostate cancer cell lines LNCaP (androgen-sensitive) and PC-3 (androgen-refractory), as well as the pro-metastatic low-density lipoprotein receptor-related protein 1 (LRP1) in the above prostate cancer cells and the nonprostate cell lines A549 (lung), HCT-15 (colon) and MG-63 (bone) under normoxic and hypoxia-like conditions. Among all cell lines, emodin showed most growth inhibition in LNCaP, followed by A549. The mechanism of cytotoxicity of emodin was postulated to be the widely reported ROS generation, based on the observations of poor in vitro radical-scavenging activity and increased growth inhibition of emodin by ascorbic acid (AA) pre-treatment owing to the additive effects of ROS generation by emodin and pro-oxidant effects of AA. Emodin downregulated AR in LNCaP under normoxic and hypoxia-like conditions (simulated by CoCl(2) ) and LRP1 under normoxia. Emodin upregulated LRP1 in other cell lines, except HCT-15, under normoxic, and even more markedly under hypoxia-like conditions. The downregulation of AR in LNCaP and upregulation of LRP1 in all cell lines, except HCT-15, under hypoxia-like conditions along with growth inhibition by emodin, suggests that emodin may be a useful therapeutic option against androgen-sensitive prostate cancer and other such LRP1-expressing cancers to attempt the targeting of the elevated LRP1 levels to allow the uptake of emodin and/or any other accompanying therapeutic agents by LRP1. Copyright © 2012 John Wiley & Sons, Ltd. PMID:23212659

Masaldan, Shashank; Iyer, Vidhya V

2012-12-01

55

High Concentrations of L-Ascorbic Acid Specifically Inhibit the Growth of Human Leukemic Cells via Downregulation of HIF-1? Transcription  

Science.gov (United States)

We examined the antileukemic effects of high concentrations of L-ascorbic acid (high AA) on human leukemic cells. In vitro, high AA markedly induced apoptosis in various leukemic cell lines by generating hydrogen peroxide (H2O2) but not in normal hematopoietic stem/progenitor cells. High AA significantly repressed leukemic cell proliferation as well as neoangiogenesis in immunodeficient mice. We then noted that in leukemic cells, HIF-1? transcription was strongly suppressed by high AA and correlated with the transcription of VEGF. Our data indicate that exposure to high AA markedly increased the intracellular AA content of leukemic cells and inhibited the nuclear translocation of NF-?B, which mediates expression of HIF-1?. We next generated K562 cells that overexpressed HIF-1? (K562-HIF1? cells) and assessed the mechanistic relationship between inhibition of HIF-1? transcription and the antileukemic effect of high AA. The ability of high AA to induce apoptosis was significantly lower in K562-HIF1? cells than in K562 cells in vitro. We found that expression of HIF-1?-regulated antiapoptotic proteins of the Bcl-2 family, such as Mcl-1, Bcl-xL, and Bcl-2, was significantly suppressed by high AA in K562 cells, but was sustained at higher levels in K562-HIF1? cells, regardless of high AA exposure. Moreover, repression of cell proliferation and neoangiogenesis by high AA was completely abrogated in mice receiving transplants of K562-HIF1? cells. These results indicate that, along with H2O2 generation, downregulation of HIF-1? transcription plays a crucial role in growth inhibition of human leukemic cells by high AA.

Sawanobori, Masakazu; Uno, Tomoko; Matsuzawa, Hideyuki; Nakamura, Yoshihiko; Matsushita, Hiromichi; Ando, Kiyoshi

2013-01-01

56

Measurement of ascorbic acid and dehydroascorbic acid in biological samples.  

UK PubMed Central (United Kingdom)

Ascorbic acid and dehydroascorbic acid are commonly used biomarkers of oxidative stress in a variety of experimental models. However, the accurate measurement of these labile compounds remains a challenge both in terms of sample collection and analysis. Determination of dehydroascorbic acid most commonly involves indirect measurement. The concentration is calculated by subtraction of the measured ascorbic acid concentration from that of total ascorbic acid analyzed after reduction of the dehydroascorbic acid present; a method referred to as the subtraction method. Consequently, successful determination of dehydroascorbic acid is dependent upon proper sample handling, quantitative reduction of the compound, and accurate quantification of both ascorbic acid and total ascorbic acid. The unit presents a detailed introduction to ascorbate analysis in biological samples and discusses common problems and pitfalls. The analytical method described is based on reversed-phase HPLC with coloumetric detection. This method includes co-analysis of isoascorbic acid and uric acid. Where applicable, uric acid can conveniently be used as an endogenous intrasample standard that significantly improves the accuracy of the subsequent dehydroascorbic acid calculation.

Lykkesfeldt J

2002-08-01

57

Measurement of ascorbic acid and dehydroascorbic acid in biological samples.  

Science.gov (United States)

Ascorbic acid and dehydroascorbic acid are commonly used biomarkers of oxidative stress in a variety of experimental models. However, the accurate measurement of these labile compounds remains a challenge both in terms of sample collection and analysis. Determination of dehydroascorbic acid most commonly involves indirect measurement. The concentration is calculated by subtraction of the measured ascorbic acid concentration from that of total ascorbic acid analyzed after reduction of the dehydroascorbic acid present; a method referred to as the subtraction method. Consequently, successful determination of dehydroascorbic acid is dependent upon proper sample handling, quantitative reduction of the compound, and accurate quantification of both ascorbic acid and total ascorbic acid. The unit presents a detailed introduction to ascorbate analysis in biological samples and discusses common problems and pitfalls. The analytical method described is based on reversed-phase HPLC with coloumetric detection. This method includes co-analysis of isoascorbic acid and uric acid. Where applicable, uric acid can conveniently be used as an endogenous intrasample standard that significantly improves the accuracy of the subsequent dehydroascorbic acid calculation. PMID:20954159

Lykkesfeldt, Jens

2002-08-01

58

Human vitamin C (L-ascorbic acid) transporter SVCT1.  

Science.gov (United States)

In human, vitamin C (l-ascorbic acid) is an essential micronutrient required for an array of biological functions including enzymatic reactions and antioxidation. We describe here the molecular cloning of a novel human cDNA encoding a vitamin C transporter SVCT1. SVCT1 is largely confined to bulk-transporting epithelia (e.g., kidney and small intestine) with a putative alternative-splice product present in thymus. Applying radiotracer and voltage-clamp approaches in cRNA-injected Xenopus oocytes, we found that SVCT1 mediates saturable, concentrative, high-affinity l-ascorbic acid transport (K(0.5) = 50-100 microM) that is electrogenic and can be inhibited by phloretin. SVCT1 displays exquisite substrate selectivity, greatly favoring l-ascorbic acid over its isomers d-isoascorbic acid and dehydroascorbic acid and 2- or 6-substituted analogues, whereas glucose and nucleobases are excluded. We have mapped the SLC23A2 gene (coding for SVCT1) to human chromosome 5 in band 5q31.2-31.3, within a region commonly deleted in malignant myeloid (leukemia) diseases. In addition, we have demonstrated that the human SLC23A1 gene product is a related high-affinity l-ascorbic acid transporter (SVCT2) that is widely distributed in brain, retina, and a host of endocrine and neuroendocrine tissues. The molecular identification of the human l-ascorbic acid transporters now provides the tools with which to investigate their roles in vitamin C metabolism in health and disease. PMID:10631088

Wang, Y; Mackenzie, B; Tsukaguchi, H; Weremowicz, S; Morton, C C; Hediger, M A

2000-01-19

59

Human vitamin C (L-ascorbic acid) transporter SVCT1.  

UK PubMed Central (United Kingdom)

In human, vitamin C (l-ascorbic acid) is an essential micronutrient required for an array of biological functions including enzymatic reactions and antioxidation. We describe here the molecular cloning of a novel human cDNA encoding a vitamin C transporter SVCT1. SVCT1 is largely confined to bulk-transporting epithelia (e.g., kidney and small intestine) with a putative alternative-splice product present in thymus. Applying radiotracer and voltage-clamp approaches in cRNA-injected Xenopus oocytes, we found that SVCT1 mediates saturable, concentrative, high-affinity l-ascorbic acid transport (K(0.5) = 50-100 microM) that is electrogenic and can be inhibited by phloretin. SVCT1 displays exquisite substrate selectivity, greatly favoring l-ascorbic acid over its isomers d-isoascorbic acid and dehydroascorbic acid and 2- or 6-substituted analogues, whereas glucose and nucleobases are excluded. We have mapped the SLC23A2 gene (coding for SVCT1) to human chromosome 5 in band 5q31.2-31.3, within a region commonly deleted in malignant myeloid (leukemia) diseases. In addition, we have demonstrated that the human SLC23A1 gene product is a related high-affinity l-ascorbic acid transporter (SVCT2) that is widely distributed in brain, retina, and a host of endocrine and neuroendocrine tissues. The molecular identification of the human l-ascorbic acid transporters now provides the tools with which to investigate their roles in vitamin C metabolism in health and disease.

Wang Y; Mackenzie B; Tsukaguchi H; Weremowicz S; Morton CC; Hediger MA

2000-01-01

60

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

UK PubMed Central (United Kingdom)

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-?-d-glucopyranosyl-l-ascorbic acid by LC-MS/MS analysis.

Kwon Taeyeon; Kim CheongTae; Lee Jong-Hoon

2007-04-01

 
 
 
 
61

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

UK PubMed Central (United Kingdom)

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.

Kwon T; Kim CT; Lee JH

2007-04-01

62

The effects of ascorbic acid on diphtheria toxin and intoxicated HeLa cells.  

UK PubMed Central (United Kingdom)

Ascorbic acid (vitamin C) prevented diphtheria toxin from inhibiting the incorporation of [U-14C]-alanine into trichloroacetic acid precipitable material in HeLa cells. Ascorbic acid did not exhibit an effect on the adenosine diphosphate-ribosylation of amino acyl transferase II nor did it separate fragment A from fragment B in "nicked" toxin. A non-specific reducing agent, para-methylaminophenol sulfate, exhibited an effect on HeLa cells very similar to the results of ascorbic acid. Citric acid, a tricarboxylic acid, had no effect on HeLa cells.

Clark CE; Smith TJ

1976-01-01

63

Ascorbic acid potentiates the inhibitory effect of dopamine on prolactin release in primary cultured rat pituitary cells.  

UK PubMed Central (United Kingdom)

The chemical structure of dopamine includes an ortho-catechol group which is labile to oxidizing agents. Ascorbic acid, a reducing agent, has in the past been added to the incubation medium in order to protect dopamine against oxidation. However, there has been no thorough examination of the biological effect of ascorbic acid on prolactin release. In this present study we have shown that ascorbic acid has neither a stimulatory nor an inhibitory effect on prolactin release but reduces by approximately two orders of magnitude the concentration of dopamine necessary to inhibit prolactin release from cultured anterior pituitary cells. The strong potentiation effect of ascorbic acid was reproduced using apomorphine. We compared the effect of ascorbic acid and isoascorbic acid on dopamine inhibition of prolactin release. Isoascorbic acid is an epimer of ascorbic acid, having the same reduction-oxidation potential as ascorbic acid, but is less biologically active. Isoascorbic acid was less effective in potentiating the dopaminergic effect than was ascorbic acid, which supports the notion that potentiation by ascorbic acid is not entirely due to its reducing property. In order to dissociate further the chemical protection of dopamine from the biological potentiation, the inhibitory effects of freshly made and 3-h-old dopamine solutions were compared. Neither one of the two solutions contained any ascorbic acid, yet the two solutions did not show any difference in their ability to inhibit prolactin release during the 3-h incubation period, indicating that no significant amount of dopamine was oxidized.(ABSTRACT TRUNCATED AT 250 WORDS)

Shin SH; Stirling R

1988-08-01

64

Topical L-ascorbic acid: percutaneous absorption studies.  

UK PubMed Central (United Kingdom)

BACKGROUND: Reactive oxygen species generated by ultraviolet light result in photocarcinogenic and photoaging changes in the skin. Antioxidants protect skin from these insults. OBJECTIVE: This study defines formulation characteristics for delivering L-ascorbic acid into the skin to supplement the skin's natural antioxidant reservoir. METHODS: L-ascorbic acid or its derivatives were applied to pig skin. Skin levels of L-ascorbic acid were measured to determine percutaneous delivery. RESULTS: L-ascorbic acid must be formulated at pH levels less than 3.5 to enter the skin. Maximal concentration for optimal percutaneous absorption was 20%. Tissue levels were saturated after three daily applications; the half-life of tissue disappearance was about 4 days. Derivatives of ascorbic acid including magnesium ascorbyl phosphate, ascorbyl-6-palmitate, and dehydroascorbic acid did not increase skin levels of L-ascorbic acid. CONCLUSIONS: Delivery of topical L-ascorbic acid into the skin is critically dependent on formulation characteristics.

Pinnell SR; Yang H; Omar M; Monteiro-Riviere N; DeBuys HV; Walker LC; Wang Y; Levine M

2001-02-01

65

Kinetic studies on the reaction of compound II of myeloperoxidase with ascorbic acid. Role of ascorbic acid in myeloperoxidase function.  

UK PubMed Central (United Kingdom)

Ascorbic acid is known to stimulate leukocyte functions. In a recent publication it was suggested that the role of ascorbic acid is to reduce compound II of myeloperoxidase back to the native enzyme (Bolscher, B. G. J. M., Zoutberg, G. R., Cuperus, R. A., and Wever, R. (1984) Biochim. Biophys. Acta 784, 189-191). In this paper we report rapid spectral scan and transient state kinetic results on the reaction of three myeloperoxidase compounds II, namely, human neutrophil myeloperoxidase, canine myeloperoxidase, and bovine spleen heme protein with ascorbate. We show by rapid scan spectra that compound II does not pass through any other intermediate when ascorbic acid reduces it back to native form. We also show that the reactions of all three compounds II involve a simple binding interaction before enzyme reduction with an apparent dissociation constant of 6.3 +/- 0.9 x 10(-4) to 2.0 +/- 0.3 x 10(-3)M and a first-order rate constant for reduction of 12.6 +/- 0.6 to 18.8 +/- 1.3 s-1. The optimum pH is 4.5, and at this pH the activation energy for the reaction is 13.2 kJ mol-1. Results of this work lend further evidence that the spleen green heme protein is very similar if not identical to leukocyte myeloperoxidase based on a comparison of spectral scans, pH-rate profiles, and kinetic parameters. We demonstrate that chloride cannot reduce compound II whereas iodide reduces compound II to native enzyme at a rate comparable to that of ascorbate. This explains why ascorbate accelerates chlorination but inhibits iodination. Formation of compound II is a dead end for the generation of hypochlorous acid; ascorbate regenerates more native enzyme to enhance the chlorination reaction namely: myeloperoxidase + peroxide----compound I followed by compound I + chloride----HOCl. On the other hand, ascorbate is a competitor with iodide for both compounds I and II and so inhibits iodination.

Marquez LA; Dunford HB; Van Wart H

1990-04-01

66

Kinetic studies on the reaction of compound II of myeloperoxidase with ascorbic acid. Role of ascorbic acid in myeloperoxidase function.  

Science.gov (United States)

Ascorbic acid is known to stimulate leukocyte functions. In a recent publication it was suggested that the role of ascorbic acid is to reduce compound II of myeloperoxidase back to the native enzyme (Bolscher, B. G. J. M., Zoutberg, G. R., Cuperus, R. A., and Wever, R. (1984) Biochim. Biophys. Acta 784, 189-191). In this paper we report rapid spectral scan and transient state kinetic results on the reaction of three myeloperoxidase compounds II, namely, human neutrophil myeloperoxidase, canine myeloperoxidase, and bovine spleen heme protein with ascorbate. We show by rapid scan spectra that compound II does not pass through any other intermediate when ascorbic acid reduces it back to native form. We also show that the reactions of all three compounds II involve a simple binding interaction before enzyme reduction with an apparent dissociation constant of 6.3 +/- 0.9 x 10(-4) to 2.0 +/- 0.3 x 10(-3)M and a first-order rate constant for reduction of 12.6 +/- 0.6 to 18.8 +/- 1.3 s-1. The optimum pH is 4.5, and at this pH the activation energy for the reaction is 13.2 kJ mol-1. Results of this work lend further evidence that the spleen green heme protein is very similar if not identical to leukocyte myeloperoxidase based on a comparison of spectral scans, pH-rate profiles, and kinetic parameters. We demonstrate that chloride cannot reduce compound II whereas iodide reduces compound II to native enzyme at a rate comparable to that of ascorbate. This explains why ascorbate accelerates chlorination but inhibits iodination. Formation of compound II is a dead end for the generation of hypochlorous acid; ascorbate regenerates more native enzyme to enhance the chlorination reaction namely: myeloperoxidase + peroxide----compound I followed by compound I + chloride----HOCl. On the other hand, ascorbate is a competitor with iodide for both compounds I and II and so inhibits iodination. PMID:2156823

Marquez, L A; Dunford, H B; Van Wart, H

1990-04-01

67

Methylglyoxal inhibition of cytosolic ascorbate peroxidase from Nicotiana tabacum.  

Science.gov (United States)

Methylglyoxal (MG) is one of the aldehydes accumulated in plants under environmental stress. Cytosolic ascorbate peroxidase (cAPX) plays a key role in the protection of cells from oxidative damage by scavenging reactive oxygen species in higher plants. A cDNA encoding cAPX, named NtcAPX, was isolated from Nicotiana tabacum. We characterized recombinant NtcAPX (rNtcAPX) as a fusion protein with glutathione S-transferase to investigate the effects of MG on APX. NtcAPX consists of 250 amino acids and has a deduced molecular mass of 27.5 kDa. The rNtcAPX showed a higher APX activity. MG treatments resulted in a reduction of APX activity and modifications of amino groups in rNtcAPX with increasing K(m) for ascorbate. On the contrary, neither NaCl nor cadmium reduced the activity of APX. The present study suggests that inhibition of APX is in part due to the modification of amino acids by MG. PMID:22696433

Hoque, Md Anamul; Uraji, Misugi; Torii, Akiko; Banu, Mst Nasrin Akhter; Mori, Izumi C; Nakamura, Yoshimasa; Murata, Yoshiyuki

2012-06-13

68

Methylglyoxal inhibition of cytosolic ascorbate peroxidase from Nicotiana tabacum.  

UK PubMed Central (United Kingdom)

Methylglyoxal (MG) is one of the aldehydes accumulated in plants under environmental stress. Cytosolic ascorbate peroxidase (cAPX) plays a key role in the protection of cells from oxidative damage by scavenging reactive oxygen species in higher plants. A cDNA encoding cAPX, named NtcAPX, was isolated from Nicotiana tabacum. We characterized recombinant NtcAPX (rNtcAPX) as a fusion protein with glutathione S-transferase to investigate the effects of MG on APX. NtcAPX consists of 250 amino acids and has a deduced molecular mass of 27.5 kDa. The rNtcAPX showed a higher APX activity. MG treatments resulted in a reduction of APX activity and modifications of amino groups in rNtcAPX with increasing K(m) for ascorbate. On the contrary, neither NaCl nor cadmium reduced the activity of APX. The present study suggests that inhibition of APX is in part due to the modification of amino acids by MG.

Hoque MA; Uraji M; Torii A; Banu MN; Mori IC; Nakamura Y; Murata Y

2012-08-01

69

L-ascorbic acid metabolism in the ascorbate-deficient arabidopsis mutant vtc1.  

Science.gov (United States)

The biosynthesis of L-ascorbic acid (vitamin C) is not well understood in plants. The ozone-sensitive Arabidopsis thaliana mutant vitamin c-1 (vtc1; formerly known as soz1) is deficient in ascorbic acid, accumulating approximately 30% of wild-type levels. This deficiency could result from elevated catabolism or decreased biosynthesis. No differences that could account for the deficiency were found in the activities of enzymes that catalyze the oxidation or reduction of ascorbic acid. The absolute rate of ascorbic acid turnover is actually less in vtc1 than in wild type; however, the turnover rate relative to the pool of ascorbic acid is not significantly different. The results from [U-14C]Glc labeling experiments suggest that the deficiency is the result of a biosynthetic defect: less L-[14C]ascorbic acid as a percentage of total soluble 14C accumulates in vtc1 than in wild type. The feeding of two putative biosynthetic intermediates, D-glucosone and L-sorbosone, had no positive effect on ascorbic acid levels in either genotype. The vtc1 defect does not appear to be the result of a deficiency in L-galactono-1,4-lactone dehydrogenase, an enzyme able to convert L-galactono-1,4-lactone to ascorbic acid. PMID:9390448

Conklin, P L; Pallanca, J E; Last, R L; Smirnoff, N

1997-11-01

70

L-ascorbic acid metabolism in the ascorbate-deficient arabidopsis mutant vtc1.  

UK PubMed Central (United Kingdom)

The biosynthesis of L-ascorbic acid (vitamin C) is not well understood in plants. The ozone-sensitive Arabidopsis thaliana mutant vitamin c-1 (vtc1; formerly known as soz1) is deficient in ascorbic acid, accumulating approximately 30% of wild-type levels. This deficiency could result from elevated catabolism or decreased biosynthesis. No differences that could account for the deficiency were found in the activities of enzymes that catalyze the oxidation or reduction of ascorbic acid. The absolute rate of ascorbic acid turnover is actually less in vtc1 than in wild type; however, the turnover rate relative to the pool of ascorbic acid is not significantly different. The results from [U-14C]Glc labeling experiments suggest that the deficiency is the result of a biosynthetic defect: less L-[14C]ascorbic acid as a percentage of total soluble 14C accumulates in vtc1 than in wild type. The feeding of two putative biosynthetic intermediates, D-glucosone and L-sorbosone, had no positive effect on ascorbic acid levels in either genotype. The vtc1 defect does not appear to be the result of a deficiency in L-galactono-1,4-lactone dehydrogenase, an enzyme able to convert L-galactono-1,4-lactone to ascorbic acid.

Conklin PL; Pallanca JE; Last RL; Smirnoff N

1997-11-01

71

ASCORBIC ACID DERIVATIVE COMPOSITION FOR INCREASING CELL RENEWAL RATE  

UK PubMed Central (United Kingdom)

The present invention relates to a method of enhancing the rate of skin desquamation by incorporating an ascorbic acid derivative into a cosmetic composition suitable for application to mammalian skin. The ascorbic acid derivative is selected from the group consisting of esters of ascorbic acid, salts, and mixtures thereof. The esters are generally selected from fatty acid mono-, di-, tri-, or tetra-esters. The salts are generally selected from ascorbyl phosphates, ascorbyl sulfates, and mixtures thereof.

SCHNEIDER Louise M.

72

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)

[en] 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

2007-06-25

73

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-06-25

74

Ascorbic acid potentiates the inhibitory effect of dopamine on prolactin release: a putative supplementary agent for PIF.  

UK PubMed Central (United Kingdom)

Dopamine has a catechol group which can be easily oxidized by mild oxidizing agents. Ascorbic acid has been routinely added to a dopamine solution in order to protect it from oxidation. We have examined the effect of ascorbic acid on dopaminergic inhibition of prolactin release. Male rat pituitary cells were dispersed using trypsin and cultured for 5-7 days before experiments. Ascorbic acid did not stimulate nor inhibit prolactin release in both static monolayer culture and dynamic perifusion systems, but potentiated by approximately 100 times the inhibitory effect of dopamine on prolactin release. In order to differentiate chemical protection from potentiation, we tested the potentiation effect of isoascorbic acid which is an epimer of biologically active L-ascorbic acid but is biologically less active. Our results indicated that isoascorbic acid caused less potentiation of the dopaminergic effect on prolactin release than did ascorbic acid. In a perifusion system, a high concentration of dopamine (100 nmol/l) was unable to inhibit prolactin release for a 1 h experimental period, but a low concentration of dopamine (10 nmol/l) plus ascorbic acid (10 mumol/l) inhibited prolactin release for the entire 1 h perifusion period. There is a strong possibility that ascorbic acid may be a physiological supplementary agent for the prolactin-release inhibiting factor (PIF) since the blood concentration of ascorbic acid is rather high (23-85 mumol/l).

Shin SH; Stirling RG; Hanna S; Lim M; Wilson JX

1990-03-01

75

Spectrophotometric determination of ascorbic acid with potassium hexacyanoferrate(III).  

Science.gov (United States)

A new, simple and rapid method of determination of ascorbic acid in amounts of 45-360 mug is described. The ascorbic acid is determined spectrophotometrically at 420 nm from the decrease in absorbance it causes in 1 x 10(-3)M hexacyanoferrate(III) in McIlvaine buffer at pH 5.2. The proposed method is suitable for the determination of ascorbic acid in pharmaceutical preparations and probably natural products. PMID:18961346

Burger, N; Karas-Gasparec, V

1973-08-01

76

Spectrophotometric determination of ascorbic acid with potassium hexacyanoferrate(III).  

UK PubMed Central (United Kingdom)

A new, simple and rapid method of determination of ascorbic acid in amounts of 45-360 mug is described. The ascorbic acid is determined spectrophotometrically at 420 nm from the decrease in absorbance it causes in 1 x 10(-3)M hexacyanoferrate(III) in McIlvaine buffer at pH 5.2. The proposed method is suitable for the determination of ascorbic acid in pharmaceutical preparations and probably natural products.

Burger N; Karas-Gasparec V

1973-08-01

77

Hepatoprotective Effect of Vitamin C (Ascorbic Acid)  

Directory of Open Access Journals (Sweden)

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

Elias Adikwu; Oputiri Deo

2013-01-01

78

ESR dosimetry of irradiated ascorbic acid.  

UK PubMed Central (United Kingdom)

PURPOSE: As an alternative to heat and gas exposure sterilization, ionizing radiation is gaining interest as a sterilization process for medicinal products. The aim of this work was to develop equations to describe the ESR curves versus dose and storage time after gamma irradiation of ascorbic acid. Several ESR data sets previously acquired in this laboratory were adopted to check the performance of the models. RESULTS: Limit of detection and limit of discrimination are respectively 0.5 kGy and 2 kGy for ascorbic acid. Linear regression is applicable for doses lower than 25 kGy. Since the radiation dose selected must always be based upon the bioburden of the products and the Degree of Sterility required (ANSI/AAMI/ISO 11137), doses in the range 5-25 kGy could be investigated and linear regression would appear to be the least expensive route to follow and gives good results. Quadratic fit, power function, exponential function and bi-exponential functions are of more general applicability to predict irradiation dose. Decay kinetics for radicals versus storage were considered. Nonhomogeneous kinetics with time-dependent rate (diffusion-controlled second-order reaction) and bi-exponential function appeared valid to reproduce the experimental data. Discrimination between irradiated and unirradiated ascorbic acid is possible after a storage of 800 days. CONCLUSIONS: It is worth noting that, at present, ESR is the only technique which proves to be suitable for identification and quantification purposes in irradiated pharmaceuticals. Moreover, other features such as sensitivity, precision, ease and non-destructive readout make ESR superior to other proposed analytical techniques.

Basly JP; Longy I; Bernard M

1997-09-01

79

The anti-inflammatory effect of lycopene complements the antioxidant action of ascorbic acid and ?-tocopherol  

UK PubMed Central (United Kingdom)

Tomato foods contain bioactive compounds, such as lycopene, ascorbic acid and ?-tocopherol, which are assumed to show synergistic effects. The aim of the study was to investigate this presumed synergy. The effect on lipid peroxidation and inflammation was assessed. Lipid peroxidation was effectively inhibited by combinations of the compounds compared to the single compounds. Synergy between the combination of ascorbic acid and ?-tocopherol was confirmed. Lycopene on its own effectively reduced inflammation by inhibiting the release of TNF-? and stimulating IL-10 production. The combination of lycopene, ascorbic acid and ?-tocopherol tended to display a synergistic interaction on IL-10 production. Our observations highlight that lycopene mitigates inflammation, whereas ascorbic acid and ?-tocopherol efficiently protect against lipid peroxidation. Both activities are complementary since they diminish the process of inflammation differently on different levels. In relation to health, this is an added value of fruit and vegetables such as tomato products that contain complementary bio-active compounds.

Hazewindus M; Haenen GRMM; Weseler AR; Bast A

2012-05-01

80

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

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

Mikirova Nina A; Casciari Joseph J; Riordan Neil H

2010-01-01

 
 
 
 
81

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

DEFF Research Database (Denmark)

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

Meyer, Anne S.; Jacobsen, Charlotte

1996-01-01

82

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)

2005-01-01

83

Development of a new ascorbic acid sensor  

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

Thiago da Cruz Canevari; Rodrigo Ferrari de Castilho; Rení Ventura da Silva Alfaya; Antonio Alberto da Silva Alfaya

2006-01-01

84

Simultaneous quantification of capsaicinoids and ascorbic acid from pungent peppers.  

UK PubMed Central (United Kingdom)

The development of simultaneous extraction and determination of bioactive molecules from natural products is becoming more popular. The present study reports the development of a method for the simultaneous extraction and determination of both capsaicinoids and ascorbic acid in peppers. Capsaicin (341.61 µg/g), dihydrocapsaicin (119.91 µg/g) and ascorbic acid (2,109.60 µg/g) were extracted with 3% metaphosphoric acid-ethanol (2:8) as a solvent. The efficient extraction of capsaicinoids (412.61 µg/g) and ascorbic acid (2,785.93 µg/g) was achieved at a sample-to-solvent ratio of 1:8 after 30 minutes of sonication. Simultaneous separation of capsaicinoids and ascorbic acid was achieved using a Gemini C18 column with a gradient elution of 0.03M phosphoric acid and methanol. Capsaicinoids and ascorbic acid were simultaneously detected at 282 and 254 nm, respectively. The recovery of capsaicinoids ranged from 96.21 to 108.71%, and the recovery of ascorbic acid ranged from 97.01 to 98.83%. The limits of detection for capsaicin, dihydrocapsaicin and ascorbic acid were 0.24, 0.21 and 0.26 µg, respectively. Relative standard deviation for the intra-day and inter-day variability in the results was less than 3%, indicating that the method produced highly reproducible results. Therefore, this method enables the reproducible, simultaneous separation and quantification of capsaicinoids and ascorbic acid from peppers.

Bae H; Jayaprakasha GK; Crosby K; Jifon JL; Patil BS

2013-05-01

85

Requirement for Na(+)-dependent ascorbic acid transport in osteoblast function.  

UK PubMed Central (United Kingdom)

Ascorbic acid is necessary for expression of the osteoblast phenotype. We examined whether Na(+)-dependent transport is required for MC3T3-E1 preosteoblast cells to respond to vitamin C and investigated the role of membrane transport in the intracellular accumulation and function of ascorbate. MC3T3-E1 cells were found to possess a saturable, stereoselective, Na(+)-dependent ascorbic acid transport activity that is sensitive to the transport inhibitors sulfinpyrazone, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, and phloretin. Transport activity showed no competition with glucose or 2-deoxyglucose and was not inhibited by cytochalasin B, indicating that it is distinct from known hexose transporters. On addition of 100 microM ascorbic acid to the extracellular medium, intracellular concentrations of 10 mM were reached within 5-10 h and remained constant for up to 24 h. A good correlation was observed between intracellular ascorbic acid concentration and rate of hydroxyproline synthesis. Although ascorbic acid was transported preferentially compared with D-isoascorbic acid, both isomers had equivalent activity in stimulating hydroxyproline formation once they entered cells. Marked stereoselectivity for extracellular L-ascorbic acid relative to D-isoascorbic acid was also seen when alkaline phosphatase and total hydroxyproline were measured after 6 days in culture. Moreover, ascorbic acid transport inhibitors that prevented intracellular accumulation of vitamin blocked the synthesis of hydroxyproline. Thus Na(+)-dependent ascorbic acid transport is required for MC3T3-E1 cells to achieve the millimolar intracellular vitamin C concentrations necessary for maximal prolyl hydroxylase activity and expression of the osteoblast phenotype.

Franceschi RT; Wilson JX; Dixon SJ

1995-06-01

86

Requirement for Na(+)-dependent ascorbic acid transport in osteoblast function.  

Science.gov (United States)

Ascorbic acid is necessary for expression of the osteoblast phenotype. We examined whether Na(+)-dependent transport is required for MC3T3-E1 preosteoblast cells to respond to vitamin C and investigated the role of membrane transport in the intracellular accumulation and function of ascorbate. MC3T3-E1 cells were found to possess a saturable, stereoselective, Na(+)-dependent ascorbic acid transport activity that is sensitive to the transport inhibitors sulfinpyrazone, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, and phloretin. Transport activity showed no competition with glucose or 2-deoxyglucose and was not inhibited by cytochalasin B, indicating that it is distinct from known hexose transporters. On addition of 100 microM ascorbic acid to the extracellular medium, intracellular concentrations of 10 mM were reached within 5-10 h and remained constant for up to 24 h. A good correlation was observed between intracellular ascorbic acid concentration and rate of hydroxyproline synthesis. Although ascorbic acid was transported preferentially compared with D-isoascorbic acid, both isomers had equivalent activity in stimulating hydroxyproline formation once they entered cells. Marked stereoselectivity for extracellular L-ascorbic acid relative to D-isoascorbic acid was also seen when alkaline phosphatase and total hydroxyproline were measured after 6 days in culture. Moreover, ascorbic acid transport inhibitors that prevented intracellular accumulation of vitamin blocked the synthesis of hydroxyproline. Thus Na(+)-dependent ascorbic acid transport is required for MC3T3-E1 cells to achieve the millimolar intracellular vitamin C concentrations necessary for maximal prolyl hydroxylase activity and expression of the osteoblast phenotype. PMID:7611363

Franceschi, R T; Wilson, J X; Dixon, S J

1995-06-01

87

Symmetric and asymmetric bolaamphiphiles from ascorbic acid.  

UK PubMed Central (United Kingdom)

The properties of novel bolaamphiphiles that carry epimers of vitamin C (L-ascorbic acid and/or D-isoascorbic acid) as hydrophilic head groups, and an interconnecting aliphatic C(12) chain (DD, DL, and LL) were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) in the solid state (anhydrous powders) and in aqueous dispersions as a function of the surfactant concentration. Upon heating, the aqueous dispersions undergo a phase transition from a hydrated semicrystalline "coagel" to a micellar phase. The results suggest that the headgroup chirality determines the formation of either inter- or intramolecular hydrogen bonds between the polar heads, which affect the phase behavior and structural properties of the nanoassemblies produced by these surfactants in water dispersions. The DSC data of aqueous dispersions were analyzed to obtain the size distribution of the pores in the coagel state.

Dolle C; Magrone P; Riva S; Ambrosi M; Fratini E; Peruzzi N; Lo Nostro P

2011-10-01

88

Symmetric and asymmetric bolaamphiphiles from ascorbic acid.  

Science.gov (United States)

The properties of novel bolaamphiphiles that carry epimers of vitamin C (L-ascorbic acid and/or D-isoascorbic acid) as hydrophilic head groups, and an interconnecting aliphatic C(12) chain (DD, DL, and LL) were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) in the solid state (anhydrous powders) and in aqueous dispersions as a function of the surfactant concentration. Upon heating, the aqueous dispersions undergo a phase transition from a hydrated semicrystalline "coagel" to a micellar phase. The results suggest that the headgroup chirality determines the formation of either inter- or intramolecular hydrogen bonds between the polar heads, which affect the phase behavior and structural properties of the nanoassemblies produced by these surfactants in water dispersions. The DSC data of aqueous dispersions were analyzed to obtain the size distribution of the pores in the coagel state. PMID:21894932

Dolle, Christian; Magrone, Pietro; Riva, Sergio; Ambrosi, Moira; Fratini, Emiliano; Peruzzi, Niccolò; Lo Nostro, Pierandrea

2011-09-19

89

[Modification of urinary pH through ascorbic acid].  

Science.gov (United States)

The influence of orally administered ascorbic acid on the urinary pH of 10 healthy volunteers and 10 patients with infected urine was investigated. During a four-day period of investigation urinary pH and the concentration of ascorbic acid in the respective urines were measured five times a day. On the second and third day three times a dose of 2 g ascorbic acid was given, while the diet was under control all four days. A correlation between pH decrease and ascorbic acid concentration is only observed if the concentration of the latter is higher than 200 mg%. The mean decrease in urinary pH between days with ascorbic acid supply and days without is -0,16 pH units for the volunteers respectively -0,18 pH units for the patients. Therefore, vitamin C can not be recommended to lower the pH of alkaline urines. PMID:7287481

Bannwart, C; Hagmaier, V; Straumann, E; Hofer, H; Vuillemier, J P; Rutishauser, G

1981-08-01

90

[Modification of urinary pH through ascorbic acid  

UK PubMed Central (United Kingdom)

The influence of orally administered ascorbic acid on the urinary pH of 10 healthy volunteers and 10 patients with infected urine was investigated. During a four-day period of investigation urinary pH and the concentration of ascorbic acid in the respective urines were measured five times a day. On the second and third day three times a dose of 2 g ascorbic acid was given, while the diet was under control all four days. A correlation between pH decrease and ascorbic acid concentration is only observed if the concentration of the latter is higher than 200 mg%. The mean decrease in urinary pH between days with ascorbic acid supply and days without is -0,16 pH units for the volunteers respectively -0,18 pH units for the patients. Therefore, vitamin C can not be recommended to lower the pH of alkaline urines.

Bannwart C; Hagmaier V; Straumann E; Hofer H; Vuillemier JP; Rutishauser G

1981-08-01

91

Kinetics of Fe(III)*EDTA reduction by ascorbic acid  

Energy Technology Data Exchange (ETDEWEB)

The kinetics of the reduction of ferric chelate by ascorbic acid have been determined at a typical flue-gas scrubber-system operating temperature ([approximately]55[degrees]C). The ascorbic acid reaction has the same reduction rate expression as the reduction by bisulfite ions, namely, first order with respect to the concentrations of both Fe(III)*EDTA and monoionic species of ascorbic acid. The reaction rate isnegative first order with respect to Fe(II)*EDTA concentration. In the pH range of 6--8, reduction of the hydrolyzed form of the metal chelate compound was negligible. The rate constant for the ascorbic acid reduction reaction is almost 400 times larger than that for the bisulfite reduction reaction under the same reaction conditions. There was no contribution associated with the nonionized form of ascorbic acid.

Li, W.; Harkness, J.B.L.; Mendelsohn, M.H.

1992-01-01

92

Ascorbic acid absorption in Crohn's disease. Studies using L-(carboxyl-/sup 14/C)ascorbic acid  

Energy Technology Data Exchange (ETDEWEB)

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-/sup 14/C)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 /sup 14/C 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 /sup 14/C 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.

Pettit, S.H.; Shaffer, J.L.; Johns, C.W.; Bennett, R.J.; Irving, M.H.

1989-04-01

93

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

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

Ioana-Anca Ieremie; Vlad Artenie

2008-01-01

94

Quantification of L-ascorbic acid and total ascorbic acid in fruits and spinach by capillary zone electrophoresis.  

Science.gov (United States)

A standard curve for the quantification of L-ascorbic acid (L-AA) by capillary zone electrophoresis (CZE) was established, and the quantification of ascorbic acid and total ascorbic acid in fruits (lemon, Sunkist, and pineapple) and spinach were performed using D-isoascorbic acid (D-IAA) as an internal standard. The minimum detection limits (MDLs) for L-AA and D-IAA were determined to be 1 and 2 microg/mL, respectively, at 265 nm. Dehydroascorbic acid (DHAA) in fruits and spinach was quantified in the presence of DL-homocysteine. The recoveries for L-AA in these juices were between 95 and 105%. PMID:11386660

Liao, T; Jiang, C M; Wu, M C; Hwang, J Y; Chang, H M

2001-05-01

95

Quantification of L-ascorbic acid and total ascorbic acid in fruits and spinach by capillary zone electrophoresis.  

UK PubMed Central (United Kingdom)

A standard curve for the quantification of L-ascorbic acid (L-AA) by capillary zone electrophoresis (CZE) was established, and the quantification of ascorbic acid and total ascorbic acid in fruits (lemon, Sunkist, and pineapple) and spinach were performed using D-isoascorbic acid (D-IAA) as an internal standard. The minimum detection limits (MDLs) for L-AA and D-IAA were determined to be 1 and 2 microg/mL, respectively, at 265 nm. Dehydroascorbic acid (DHAA) in fruits and spinach was quantified in the presence of DL-homocysteine. The recoveries for L-AA in these juices were between 95 and 105%.

Liao T; Jiang CM; Wu MC; Hwang JY; Chang HM

2001-05-01

96

Ascorbic acid contents of Pakistani fruits and vegetables.  

Science.gov (United States)

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

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

2006-10-01

97

Ascorbic acid contents of Pakistani fruits and vegetables.  

UK PubMed Central (United Kingdom)

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.

Iqbal MP; Kazim SF; Mehboobali N

2006-10-01

98

Synthesis of New L-Ascorbic Ferulic Acid Hybrids  

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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 p...

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

99

Synthesis of New L-Ascorbic Ferulic Acid Hybrids  

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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.

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

2007-01-01

100

THE EFFECTS OF ASCORBIC ACID ON MEMBRANE TRANSPORT OF GLUCOSE  

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

Voja Pavlovic; Zoran Pavlovic

2004-01-01

 
 
 
 
101

THE EFFECTS OF ASCORBIC ACID ON MEMBRANE TRANSPORT OF GLUCOSE  

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

Voja Pavlovic; Zoran Pavlovic

2004-01-01

102

THE EFFECT OF ASCORBIC ACID ON BLAST TRANSFORMATION OF LYMPHOCYTES  

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

Voja Pavlovi?; Zoran Pavlovi?; Zorica Anti?

2003-01-01

103

Expression of a rabbit renal ascorbic acid transporter in Xenopus laevis oocytes.  

Science.gov (United States)

We examined the expression of renal ascorbic acid transporter(s) in Xenopus laevis oocytes after microinjection of cells with poly(A)+ RNA extracted from rabbit kidney cortex. Concomitant expression of the Na+-glucose cotransporter served as a control in these studies. Injection of poly(A)+ RNA into oocytes produced over a fivefold increase in the uptake of [14C]ascorbic acid (570 microM) compared with water-injected cells. Size fractionation of the kidney cortex mRNA by sucrose gradient revealed that the mRNA species that induced ascorbic acid transporter expression in oocytes was present in a fraction centered around 2.0 kilobases (kb) and had a size range of 1.8-3.1 kb. Injection of the active fraction into oocytes produced a > 40-fold increase in ascorbic acid uptake compared with water-injected controls. Expression of ascorbic acid transporter(s) was noticeable as early as 2 days after injection and was maximal after 7 days; it was also dependent on the amount of mRNA injected into oocytes. The induced uptake of [14C]ascorbic acid after injection of mRNA into oocytes was 1) Na+ dependent, as indicated by the almost complete lack of transport on removal of Na+ from the incubation medium; 2) significantly inhibited by unlabeled ascorbic acid and its structural analogue isoascorbic acid but not by D-glucose; and 3) saturable as a function of increasing the substrate concentration in the incubation medium (100-1,000 microM), with an apparent Km of 258 +/- 72.5 microM and a maximum velocity of 29.6 +/- 2.8 pmol.oocyte-1.2 h-1. These data demonstrate that X. laevis oocytes are a suitable system to functionally express the mammalian renal ascorbic acid transporter.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7519399

Dyer, D L; Kanai, Y; Hediger, M A; Rubin, S A; Said, H M

1994-07-01

104

Expression of a rabbit renal ascorbic acid transporter in Xenopus laevis oocytes.  

UK PubMed Central (United Kingdom)

We examined the expression of renal ascorbic acid transporter(s) in Xenopus laevis oocytes after microinjection of cells with poly(A)+ RNA extracted from rabbit kidney cortex. Concomitant expression of the Na+-glucose cotransporter served as a control in these studies. Injection of poly(A)+ RNA into oocytes produced over a fivefold increase in the uptake of [14C]ascorbic acid (570 microM) compared with water-injected cells. Size fractionation of the kidney cortex mRNA by sucrose gradient revealed that the mRNA species that induced ascorbic acid transporter expression in oocytes was present in a fraction centered around 2.0 kilobases (kb) and had a size range of 1.8-3.1 kb. Injection of the active fraction into oocytes produced a > 40-fold increase in ascorbic acid uptake compared with water-injected controls. Expression of ascorbic acid transporter(s) was noticeable as early as 2 days after injection and was maximal after 7 days; it was also dependent on the amount of mRNA injected into oocytes. The induced uptake of [14C]ascorbic acid after injection of mRNA into oocytes was 1) Na+ dependent, as indicated by the almost complete lack of transport on removal of Na+ from the incubation medium; 2) significantly inhibited by unlabeled ascorbic acid and its structural analogue isoascorbic acid but not by D-glucose; and 3) saturable as a function of increasing the substrate concentration in the incubation medium (100-1,000 microM), with an apparent Km of 258 +/- 72.5 microM and a maximum velocity of 29.6 +/- 2.8 pmol.oocyte-1.2 h-1. These data demonstrate that X. laevis oocytes are a suitable system to functionally express the mammalian renal ascorbic acid transporter.(ABSTRACT TRUNCATED AT 250 WORDS)

Dyer DL; Kanai Y; Hediger MA; Rubin SA; Said HM

1994-07-01

105

Modifications induced by ascorbic acid on alkaline phosphatase fluorescence.  

UK PubMed Central (United Kingdom)

Ascorbic acid, isoascorbic acid and dehydroascorbic acid quench the tryptophyl fluorescence of alkaline phosphatase. The quenching is protein aspecific, although its extent reflects the different inhibitory efficiency of the compounds. The kinetic inactivation and emission deactivation of alkaline phosphatase isoenzymes present also striking similarities. The fluorescence modifications, moreover, show a particular pattern, indicative of a transition phenomenon. The quenching effects displayed by the ascorbic system on alkaline phosphatase can then supply an interesting insight into other aspects of the inhibitor-enzyme interaction.

Martorana GE; Meucci E; Miggiano GA; Mordente A; Ursitti A; Castelli A

1984-09-01

106

Radiation protection by ascorbic acid in sodium alginate solutions  

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

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

2004-07-01

107

Effects of ascorbic acid and analogs on the activity of testicular hyaluronidase and hyaluronan lyase on hyaluronan.  

UK PubMed Central (United Kingdom)

We have evaluated the inhibition of testicular hyaluronidase and hyaluronan lyase by L-ascorbic acid and chemical analogs. We observed that L-ascorbic acid, D-isoascorbic acid and dehydroascorbic acid inhibited both types of enzymes, but showed stronger effects towards hyaluronan lyase. But these compounds were observed to degrade the substrate, hyaluronan, by themselves. Of the other ascorbic acid analogs tested, saccharic acid inhibited hyaluronan lyase, while not affecting the enzymatic activity of testicular hyaluronidase, nor affecting the physic-chemical stability of hyaluronan. This is the first compound, to our knowledge, to be shown to possess such selective inhibition. Therefore, we propose that saccharic acid could serve as a lead compound for the development of potent and selective inhibitors of bacterial hyaluronan lyase or of polysaccharide lyase enzymes in general as we observed this compound to be capable of inhibiting chondroitinase ABC in addition to hyaluronan lyase.

Okorukwu ON; Vercruysse KP

2003-08-01

108

Effects of ascorbic acid and analogs on the activity of testicular hyaluronidase and hyaluronan lyase on hyaluronan.  

Science.gov (United States)

We have evaluated the inhibition of testicular hyaluronidase and hyaluronan lyase by L-ascorbic acid and chemical analogs. We observed that L-ascorbic acid, D-isoascorbic acid and dehydroascorbic acid inhibited both types of enzymes, but showed stronger effects towards hyaluronan lyase. But these compounds were observed to degrade the substrate, hyaluronan, by themselves. Of the other ascorbic acid analogs tested, saccharic acid inhibited hyaluronan lyase, while not affecting the enzymatic activity of testicular hyaluronidase, nor affecting the physic-chemical stability of hyaluronan. This is the first compound, to our knowledge, to be shown to possess such selective inhibition. Therefore, we propose that saccharic acid could serve as a lead compound for the development of potent and selective inhibitors of bacterial hyaluronan lyase or of polysaccharide lyase enzymes in general as we observed this compound to be capable of inhibiting chondroitinase ABC in addition to hyaluronan lyase. PMID:14567553

Okorukwu, Odilia N; Vercruysse, Koen P

2003-08-01

109

Effect of Ascorbic Acid on Lipid Peroxidation Induced by Ceftazidime  

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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.

Devbhuti P*,1; Devbhuti D2; Saha A3; Sengupta C4

2011-01-01

110

BROWNING INHIBITOR CONTAINING ASCORBIC ACID 2-GLUCOSIDE AS THE ACTIVE INGREDIENT AND METHOD FOR INHBITING BROWNING WITH THE SAME  

UK PubMed Central (United Kingdom)

The invention aims at providing a method for inhibiting the browning and/or stinking of a composition and thus improving the storage stability of the composition. The aim is attained by a method which comprises adding a browning inhibitor containing ascorbic acid 2-glucoside as the active ingredient to a composition to inhibit the discoloration and/or stinking of the composition by virtue of gradual and continuous decrease in the ascorbic acid 2-glucoside.

KUBOTA Michio; FUKUSHIMA Hideki; MIYAKE Toshio

111

Investigations of ascorbic acid interference in urine test strips.  

Science.gov (United States)

Ascorbic acid at higher concentration in urine samples can lead to false negative results in a number of urine tests, with a potential risk of clinical findings being overlooked, particularly with glucose and hemoglobin. For this reason, the ascorbic acid status of urine samples should always be routinely known so as to establish what adjustment needs to be made. A much better approach, however, is to use a test which is by design largely resistant to ascorbic acid. We compared five very common 10-parameter urine test strips from different manufacturers. The results of this study show that of the strips tested, only the product Combur-Test from Roche Diagnostics is largely resistant to ascorbic acid interference. Even lowest - but clinically relevant - concentrations of erythrocytes (10/microL), hemoglobin (0.03 mg/dL), and glucose (50 mg/dL) were correctly detected with concentrations of up to 400 mg/L ascorbic acid. Higher analyte concentrations correctly reacted positive even in the presence of up to 1000 mg/L ascorbic acid. PMID:16584061

Nagel, Dietmar; Seiler, Dieter; Hohenberger, Ewald F; Ziegler, Manfred

2006-01-01

112

Investigations of ascorbic acid interference in urine test strips.  

UK PubMed Central (United Kingdom)

Ascorbic acid at higher concentration in urine samples can lead to false negative results in a number of urine tests, with a potential risk of clinical findings being overlooked, particularly with glucose and hemoglobin. For this reason, the ascorbic acid status of urine samples should always be routinely known so as to establish what adjustment needs to be made. A much better approach, however, is to use a test which is by design largely resistant to ascorbic acid. We compared five very common 10-parameter urine test strips from different manufacturers. The results of this study show that of the strips tested, only the product Combur-Test from Roche Diagnostics is largely resistant to ascorbic acid interference. Even lowest - but clinically relevant - concentrations of erythrocytes (10/microL), hemoglobin (0.03 mg/dL), and glucose (50 mg/dL) were correctly detected with concentrations of up to 400 mg/L ascorbic acid. Higher analyte concentrations correctly reacted positive even in the presence of up to 1000 mg/L ascorbic acid.

Nagel D; Seiler D; Hohenberger EF; Ziegler M

2006-01-01

113

Browning in ethanolic solutions of ascorbic acid and catechin.  

UK PubMed Central (United Kingdom)

Nonenzymatic browning occurs readily in alcoholic beverages and degrades their color quality. Ascorbic acid degradation in the presence of phenolic compounds is a major browning pathway in alcoholic beverages with fruit or fruit juice as the raw material or an ingredient. In the present study ethanolic solutions of ascorbic acid and catechin were prepared to simulate the alcoholic beverages. Ascorbic acid degradation and browning in these model solutions were investigated. Glycerol solutions with the same water activity (A(w)) values as those of the ethanolic model solutions were used as controls in the evaluation of browning rate. Results showed that the aerobic degradation of ascorbic acid dominates over the anaerobic one in ethanolic solutions, that the browning rate decreases as the ethanol concentration increases, that the compound 3-hydroxy-2-pyrone may not be a good indicator of browning in ethanolic ascorbic acid-catechin solutions, and that A(w) is a major factor responsible for the difference in the browning rate among ascorbic acid-catechin solutions with different ethanol concentrations.

Chuang PT; Shen SC; Wu JS

2011-07-01

114

Ascorbic acid: Nonradioactive extracellular space marker in canine heart  

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The distribution pattern of ascorbic acid and L-({sup 14}C)ascorbic acid in myocardial tissue was compared with those of the classical radioactive extracellular space markers ({sup 3}H)-inulin, ({sup 3}H)sucrose, and Na{sup 82}Br. A new polarographic techniques was developed for analogue registration of ascorbic acid concentration in coronary venous blood. The kinetic data of the markers were studied in an open-chest canine heart preparation during a constant tracer infusion of up to 9 min. Distribution volumes were calculated based on the mean transit time method of Zierler. The distribution volume of ascorbic acid as well as of L-({sup 14}C)ascorbic acid in myocardial tissue agreed closely with those of ({sup 3}H)inulin and ({sup 3}H)sucrose as well as {sup 82}Br. The obtained kinetic data confirmed that ascorbic acid exhibits the physicochemical properties of an extracellular space marker, though this compound was shown to leak slowly into myocardial cells. Favorable attributes of this indicator are its low molecular weight, high diffusibility in interstitial fluid, low binding affinity to macromolecules, and high transcapillary as well as low transplasmalemmal penetration rate. Therefore, this nonradioactive marker can be applied in a safe and simple fashion, and without untoward side effects in experimental animals as well as in patients.

Reil, G.H.; Frombach, R.; Kownatzki, R.; Quante, W.; Lichtlen, P.R. (Medizinische Hochschule Hannover (West Germany))

1987-11-01

115

Ascorbic acid: Nonradioactive extracellular space marker in canine heart  

International Nuclear Information System (INIS)

The distribution pattern of ascorbic acid and L-[14C]ascorbic acid in myocardial tissue was compared with those of the classical radioactive extracellular space markers [3H]-inulin, [3H]sucrose, and Na82Br. A new polarographic techniques was developed for analogue registration of ascorbic acid concentration in coronary venous blood. The kinetic data of the markers were studied in an open-chest canine heart preparation during a constant tracer infusion of up to 9 min. Distribution volumes were calculated based on the mean transit time method of Zierler. The distribution volume of ascorbic acid as well as of L-[14C]ascorbic acid in myocardial tissue agreed closely with those of [3H]inulin and [3H]sucrose as well as 82Br. The obtained kinetic data confirmed that ascorbic acid exhibits the physicochemical properties of an extracellular space marker, though this compound was shown to leak slowly into myocardial cells. Favorable attributes of this indicator are its low molecular weight, high diffusibility in interstitial fluid, low binding affinity to macromolecules, and high transcapillary as well as low transplasmalemmal penetration rate. Therefore, this nonradioactive marker can be applied in a safe and simple fashion, and without untoward side effects in experimental animals as well as in patients

1987-01-01

116

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

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The influence of solutions of ascorbic acid, thiamine, L-arginine, and L-gtutamic acid on egg hatch, juvenile survival, and development and reproduction of Meloidogyne incognita in susceptible and resistant tomatoes was studied. Maximum inhibition of egg hatch occurred at 2,000, 4,000, and 2,000 ppm...

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

117

Ascorbic acid biosynthesis in Amazonian fishes.  

UK PubMed Central (United Kingdom)

The incapacity to synthesize ascorbic acid (AA) is due to the lack of activity of L-gulonolactone oxidase (GLO), which catalyzes the last step of AA biosynthesis. It was postulated that vertebrates unable to synthesize AA had sufficient amounts of this nutrient in their diet and consequently did not need to preserve synthetic capability. In the present study, we analyzed the GLO activity in kidney and liver of 13 fish species, including 11 teleosts, namely: freshwater stingray, Potamotrygon sp.; South American lungfish, Lepidosiren paradoxa; "sardinhao," Pelona sp.; arowana, Osteoglossum bicirrhosum; arapaima, Arapaima gigas; "piranha caju," Pygocentrus nattereri; "piranha mucura," Serrasalmus elongatus; "aracu," Schizodon fasciatus; "tambaqui," Colossoma macropomum; "acari-pedra," Hypostomus sp.; "sarapo," Steatogenys elegans; electric eel, Electrophorus electricus; and the peacock bass, Cichla sp. Four representatives of the Characiformes order with distinct feeding habits were included in this study to evaluate the influence of feeding habit on GLO activity. Only two species of non-teleost fishes, the freshwater stingray (Miliobatiformes) and the South American lungfish (Lepidosireniformes), showed GLO activity in their kidneys, corroborating the hypothesis that teleosts are unable to synthesize AA. Additionally, as expected, we observed that the phylogenetic position is more important than feeding habit as a determinant of the biosynthetic ability since none of the Characiformes species analyzed synthesize AA, independent of their distinct feeding habits. Female freshwater stingrays had a significantly higher GLO activity than males (P < 0.05), but there was no difference in the biosynthetic capability regarding the portion of the kidney analyzed (P > 0.05), as previously reported in white sturgeon. This is the first report of the AA biosynthetic ability in South American lungfish and freshwater Elasmobranchs.

Fracalossi DM; Allen ME; Yuyama LK; Oftedal OT

2001-01-01

118

The antiscorbutic action of L-ascorbic acid and D-isoascorbic acid (erythorbic acid) in the guinea pig.  

UK PubMed Central (United Kingdom)

Female guinea pigs were fed a scorbutigenic diet supplemented with either L-ascorbic acid or D-isoascorbic acid or combinations of these. Their responses were judged by changes in body weight, serum alkaline phosphatase levels, wound healing, and tooth structure. Large additions (100 mg daily) of D-isoascorbic acid to the scorbutigenic diet resulted in normal growth over a 7-wk period and normal serum alkaline phosphatase levels, tooth structure development, and collagen formation after wounding. The addition of 0.5 or 5.0 mg of L-ascorbic acid to this high D-isoascorbic diet improved neither growth rate nor collagen deposition during wound healing. On the basis of changes in tooth structure, D-isoascorbic acid has 1/20 the potency of L-ascorbic acid. Its effect is additive to subminimal maintenance levels of L-ascorbic acid implying that there is no competitive inhibition in the utilization of the two compounds. The relatively weak activity of D-isoascorbic acid is probably due to poor transport to the tissues and ineffective binding to functional sites. This explains why the onset of scurvy is much more rapid after withdrawal of D-isoascorbic acid from the diet when it had been the sole antiscorbutic dietary constituent. It is concluded that D-isoascorbic acid is a "weakly" antiscorbutic agent on the basis that it is both poorly absorbed and retained by the tissue; that in fact it may, to the degree that it is taken up by the tissues and retained, be equal in antiscorbutic potency to L-ascorbic acid.

Goldman HM; Gould BS; Munro HN

1981-01-01

119

Effects of ascorbic acid on gingival melanin pigmentation in vitro and in vivo.  

UK PubMed Central (United Kingdom)

BACKGROUND: Gingival melanin pigmentation may cause esthetic concerns, even if no serious medical problem is present. As an inhibitor of melanin formation, ascorbic acid is often used to treat skin melanin pigmentation. Thus, the present study investigated the effects of ascorbic acid on gingival melanin pigmentation in vitro and in vivo. METHODS: The effects of ascorbic acid on melanin formation were evaluated in vitro in B16 mouse melanoma cells and three-dimensional human skin models. In addition, a clinical trial was performed to investigate the inhibitory effects of a gel containing ascorbic acid 2-glucoside (AS-G gel) on gingival melanin pigmentation. This study used a double-masked, split-mouth design on 73 subjects with symmetric gingival melanin pigmentation. AS-G gel was applied to one side of the gingiva for 12 weeks, whereas placebo gel was applied to the other side as a control. Luminance (L*)-value, which describes the lightness of gingiva, was determined by spectrophotometry to obtain an objective measure of melanin pigmentation every 4 weeks. RESULTS: Ascorbic acid significantly inhibited tyrosinase activity and melanin formation in B16 mouse melanoma cells (P <0.01 and P <0.05, respectively). The inhibitory effects of ascorbic acid on melanin formation were also significant in three-dimensional human skin models (P <0.01). Moreover, in the clinical trial, a significant relative change in pigmentation was seen after 4 weeks with the application of AS-G gel compared to placebo (L*-value ratio). CONCLUSION: Ascorbic acid (AS-G) has potential for the treatment of gingival melanin pigmentation.

Shimada Y; Tai H; Tanaka A; Ikezawa-Suzuki I; Takagi K; Yoshida Y; Yoshie H

2009-02-01

120

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)

1998-01-01

 
 
 
 
121

[Decrease in the ascorbic acid content of guinea pig tissues caused by thalidomide  

UK PubMed Central (United Kingdom)

It has been demonstrated that thalidomide is capable of a noticeable stabilization of the enzymes from rabbit, pig and guinea-pig liver microsomal fractions. Administration of thalidomide to guinea-pigs resulted in an increase of microsomal hydroxylase activity measured by the aniline test. The growth of the activity of microsomal enzymes led to an abrupt drop of ascorbic acid concentration in guinea-pig organs. It is suggested that thalidomide has a teratogenic action on the species which are incapable of the synthesis of ascorbic acid by making this vitamin deficiency in embryonal tissues. Probably, it is the deficiency of ascorbic acid that inhibits the synthesis of collagen in embryonal limbs and disturbs their sensory ganglia.

Va?sman BL; Popov VB; Ignat'eva TV

1983-07-01

122

Ascorbic acid enables reversible dopamine receptor /sup 3/H-agonist binding  

Energy Technology Data Exchange (ETDEWEB)

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

Leff, S.; Sibley, D.R.; Hamblin, M.; Creese, I.

1981-11-16

123

Anti-stress agent for animals comprising an ascorbic acid derivative  

UK PubMed Central (United Kingdom)

An anti-stress agent for animals for reducing the growth inhibition or mortality of animals and a method of reducing stress using a feed composition having blended therein the anti-stress agent. The anti-stress agent for animals comprises one or more substances selected from an L-ascorbic acid-2-phosphoric acid, a salt thereof and an L-ascorbic-acid-2-glucoside, as an active ingredient, for inhibiting the increase of blood plasma lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and aspartate aminotransferase (AspAT) and for inhibiting the increase of stress proteins in blood, which occur when animals are placed under stress. Also disclosed is a feed composition comprising the anti-stress agent; and a method of reducing the stress of animals by supplying the same as feed.

Ito Shinobu; Ogata Eiji; Yamada Masahiro

124

PDMS-based gold electrode for sensing ascorbic acid.  

Science.gov (United States)

Electrode with optical shapes is appreciated in microfluidics. In this article, we reported a flexible poly(dimethylsiloxane) (PDMS)-based gold electrode for ascorbic acid detection. Gold nanoparticles were chemically deposited on PDMS and the composite film was applied as working electrode. The electrode could undergo deformation and display good response performance without damage. This biosensor could give quick response to ascorbic acid (AA) (<5s) and the currents were linear with concentrations of AA in range of 0.023-7.00 mM and 30-100 mM, respectively. Limit of detection was 0.008 mM (S/N=3). This biosensor has been applied to determine ascorbic acid content in vitamin C tablets and the results were consistent with traditional iodometric method. PMID:21807485

Xu, Qin; Bi, Lianhua; Zheng, Huxiang; Fan, Dahe; Wang, Wei

2011-07-12

125

PDMS-based gold electrode for sensing ascorbic acid.  

UK PubMed Central (United Kingdom)

Electrode with optical shapes is appreciated in microfluidics. In this article, we reported a flexible poly(dimethylsiloxane) (PDMS)-based gold electrode for ascorbic acid detection. Gold nanoparticles were chemically deposited on PDMS and the composite film was applied as working electrode. The electrode could undergo deformation and display good response performance without damage. This biosensor could give quick response to ascorbic acid (AA) (<5s) and the currents were linear with concentrations of AA in range of 0.023-7.00 mM and 30-100 mM, respectively. Limit of detection was 0.008 mM (S/N=3). This biosensor has been applied to determine ascorbic acid content in vitamin C tablets and the results were consistent with traditional iodometric method.

Xu Q; Bi L; Zheng H; Fan D; Wang W

2011-11-01

126

Urinary ascorbic acid--HPLC determination and application as a noninvasive biomarker of hepatic response.  

Science.gov (United States)

A high-performance liquid chromatograph (HPLC) procedure has been developed for the determination of rat urinary ascorbic acid, a major metabolite of the hepatic glucuronic acid pathway. The presence of EDTA and HCl effectively inhibited degradation of ascorbic acid during the collection of urine specimens. The reliability of the procedure was demonstrated by its high recovery (90%), specificity (characteristic absorption maximum and discrimination from isoascorbic acid), and reproducibility (2-3% coefficient of variation). The usefulness of this assay as an indicator of hepatic response was demonstrated in preliminary experiments where increases in urinary ascorbic acid excretion were detected in male rats treated with PCB 126 (3,3',4,4',5-pentachlorobiphenyl) or PCB 105 (2,3,3',4,4'-pentachlorobiphenyl). The HPLC measurement also showed that the two PCB congeners differed markedly in their potency in stimulating urinary ascorbic acid excretion. For example, 10 micrograms/kg bw/day of PCB 126 was sufficient to cause a fourfold increase in urinary ascorbic excretion while 5000 micrograms/kg bw/day of PCB 105 was required for a sevenfold increase. In response to the administration of PCB 105 or PCB 126, urinary ascorbic acid appeared to increase to the same extent as increases in hepatic ethoxyresorufin O-deethylase (EROD) and UDP-glucuronosyltransferase (UGT) activities, and to a much higher extent than changes in liver weight and hematological and serum clinical chemical parameters. The sensitivity and specificity, the ease in obtaining timed specimens, and the noninvasive nature make this assay a useful biomarker of hepatic response in dose-finding and various acute and chronic studies. PMID:7891365

Poon, R; Chu, I; Lecavalier, P; Bergman, A; Villeneuve, D C

1994-12-01

127

Urinary ascorbic acid--HPLC determination and application as a noninvasive biomarker of hepatic response.  

UK PubMed Central (United Kingdom)

A high-performance liquid chromatograph (HPLC) procedure has been developed for the determination of rat urinary ascorbic acid, a major metabolite of the hepatic glucuronic acid pathway. The presence of EDTA and HCl effectively inhibited degradation of ascorbic acid during the collection of urine specimens. The reliability of the procedure was demonstrated by its high recovery (90%), specificity (characteristic absorption maximum and discrimination from isoascorbic acid), and reproducibility (2-3% coefficient of variation). The usefulness of this assay as an indicator of hepatic response was demonstrated in preliminary experiments where increases in urinary ascorbic acid excretion were detected in male rats treated with PCB 126 (3,3',4,4',5-pentachlorobiphenyl) or PCB 105 (2,3,3',4,4'-pentachlorobiphenyl). The HPLC measurement also showed that the two PCB congeners differed markedly in their potency in stimulating urinary ascorbic acid excretion. For example, 10 micrograms/kg bw/day of PCB 126 was sufficient to cause a fourfold increase in urinary ascorbic excretion while 5000 micrograms/kg bw/day of PCB 105 was required for a sevenfold increase. In response to the administration of PCB 105 or PCB 126, urinary ascorbic acid appeared to increase to the same extent as increases in hepatic ethoxyresorufin O-deethylase (EROD) and UDP-glucuronosyltransferase (UGT) activities, and to a much higher extent than changes in liver weight and hematological and serum clinical chemical parameters. The sensitivity and specificity, the ease in obtaining timed specimens, and the noninvasive nature make this assay a useful biomarker of hepatic response in dose-finding and various acute and chronic studies.

Poon R; Chu I; Lecavalier P; Bergman A; Villeneuve DC

1994-12-01

128

[Effect of thiamine, riboflavin and ascorbic acid on tetracycline, erythromycin and levomycetin activity  

UK PubMed Central (United Kingdom)

The effect of antibiotics was estimated by inhibition of the protein increase in the broth culture of Staph, aureus during incubation at a temperature of 37 degrees for 18 hours. In some experiments preincubation of the antibiotic solutions with the vitamins for 2 hours at light and in dark was used. The antibiotic concentrations in gamma per 1 ml were equal to those of the vitamins. In the experiments with tetracycline and 2-hour preincubation at light the antibiotic in a concentration of 0.1gamma ml inhibited for certain the protein increase by 58.9%, in combination with thiamin it inhibited the protein by 60 per cent and in combination with ascorbic acid by 59%. Riboflavin lowered the activity of tetracycline to a value not differing for certain from the control one. In the experiments with preincubation in dark tetracycline inhibited the protein increase by 55.2%, in combination with thiamin it inhibited the protein increase by 50.5%, in combination with riboflavin by 53% and in combination with ascorbic acid by 57.2%. Erythromycin in a concentration of 0.03gamma/ml when preincubated at light inhibited the protein increase by 48.8% and in combinations with thiamin, riboflavin or ascorbic acid by 23, 27, 47.2% respectively. When preincubated in the darkness erythromycin alone inhibited the protein increase by 47.8% and in combinations with thiamin, riboflavin or ascorbic acid by 32.5, 51.1 or 49.8% respectively. The above vitamins has no effect on levomycetin activity.

Velizhenko GG

1975-06-01

129

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

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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.

Mohammad Amani; Ali Noroozzadeh; Reza Badalzadeh; Ali Khoshbaten

2010-01-01

130

Low-volume plus ascorbic acid vs high-volume plus simethicone bowel preparation before colonoscopy  

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AIM: To investigate the effectiveness of low-volume plus ascorbic acid [polyethylene glycol plus ascorbic acid (PEG + Asc)] and high-volume plus simethicone [polyethylene glycol plus simethicone (PEG + Sim)] bowel preparations.

Pontone, Stefano; Angelini, Rita; Standoli, Monica; Patrizi, Gregorio; Culasso, Franco; Pontone, Paolo; Redler, Adriano

131

Reduction of hexavalent chromium by ascorbic acid in aqueous solutions  

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Hexavalent chromium is a priority pollutant in the USA and many other countries. Reduction of Cr(VI) to Cr(III) is environmentally favorable as the latter species is not toxic to most living organisms and also has a low mobility and bioavailability. Reduction of Cr(VI) by ascorbic acid (vitamin C) a...

Xu, XR; Li, HB; Li, XY; Gu, JD

132

Regulation of L-ascorbic acid content in strawberry fruits  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Plants have several L-ascorbic acid (AsA) biosynthetic pathways, but the contribution of each one to the synthesis of AsA varyies between different species, organs, and developmental stages. Strawberry (Fragaria×ananassa) fruits are rich in AsA. The pathway that uses D-galacturonate as the initial s...

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

133

Ascorbic acid estimation in aqueous humour of normal cataractous and aphakic eyes  

Directory of Open Access Journals (Sweden)

Full Text Available Ascorbic acid has received a great deal of attention in lens metabolism. A good number of workers have estimated aqueous humour and serum ascorbic acid values in animals and human beings. But the question whether the concentration of ascorbic acid in aqueous humour varies in normal, cataractous and aphakic patients is still disputed.

Khurrum M

1988-01-01

134

Palmitoyl ascorbate liposomes and free ascorbic acid: comparison of anticancer therapeutic effects upon parenteral administration.  

UK PubMed Central (United Kingdom)

PURPOSE: To evaluate and compare anticancer therapeutic effect of palmitoyl ascorbate liposomes (PAL) and free ascorbic acid (AA). METHODS: Liposomes incorporating palmitoyl ascorbate (PA) were prepared and evaluated for PA content by HPLC. To elucidate mechanism of action of cell death in vitro, effect of various H(2)O(2) scavengers and metal chelators on PA-mediated cytotoxicity was studied. Effect of various combinations of PAL and free AA on in vitro cytotoxicity was evaluated on 4T1 cells. In vivo, PAL formulation was modified with polyethylene glycol; effect of PEGylation on in vitro cytotoxicity was evaluated. Biodistribution of PEG-PAL formulation was investigated in female Balb/c mice bearing murine mammary carcinoma (4T1 cells). In vivo anticancer activity of PEG-PAL (PEG-PAL equivalent to 20 mg/kg of PA injected intravenously on alternate days) was compared with free AA therapy in same model. RESULTS: PEG-PAL treatment was significantly more effective than free AA treatment in slowing tumor growth. CONCLUSIONS: Nanoparticle formulations incorporating PA can kill cancer cells in vitro. The mechanism of PA cytotoxicity is based on production of extracellular reactive oxygen species and involves intracellular transition metals.

Sawant RR; Vaze OS; Wang T; D'Souza GG; Rockwell K; Gada K; Khaw BA; Torchilin VP

2012-02-01

135

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

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

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

2009-01-01

136

COSMETIC COMPOSITION COMPRISING ASCORBIC ACID 2-GLUCOSIDE AND ERGOTHIONEINE  

UK PubMed Central (United Kingdom)

A cosmetic composition containing an ascorbic acid 2-glucoside and ergothioneine, which reduces or delays the skin aging, is provided to stimulate a repair enzyme of oxidized DNA in epidermis and dermis. A cosmetic composition comprises 0.0001 weight%-10 weigh% of ascorbic acid 2-glucoside, 0.0001 weight%-10 weight% of ergothioneine, and cosmetically allowable excipient. The cosmetic composition further comprises depigmenting agent or agent which reduces or delays the effect of skin aging. The depigmenting agent is vitamin B3, calcium D-pantetheine-S-sulphonate, liquorice extracts, ferulic acid, citrus unshiu extracts and diacetylboldine. The agent which reduces or delays the effect of skin aging is retinol, retinol ester, tocopherol derivatives, or asiaticoside. The cosmetic composition is used in a form of pressed powder, lotion, gel, serum, cream, patch, or mask.

KURFURST ROBIN; BONNET DUQUENNOY MATHILDE

137

[Effect of L-ascorbic and D-isoascorbic acids on induced formation of tyrosine aminotransferase in rat liver  

UK PubMed Central (United Kingdom)

Administration of ascorbic acid at moderate doses/0.05-0.1 g per kg of body mass/was shown to induce tyrosine transaminase in liver tissue of intact rats. The enzyme induction depended on the state of adrenal glands and was inhibited by actinomycin D. As distinct from the native form of L-ascorbic acid moderate doses of D-isoascorbic acid did not induce the enzyme in rat liver tissue; these data suggest the relative biological inactivity of D-isoascorbic acid.

Levchuk AA; Bukin IuV; Smirnova KD; Raushenbakh MO; Rubtsov IA

1981-01-01

138

Report on Third Year of Research on Ascorbic Acid, Biological Function and Chemistry.  

Science.gov (United States)

The following areas were investigated: (1) Chemistry of the ascorbic and isoascorbic acids and their oxidation products (Bell); (2) Synthesis of L-ascorbic-6-14C acid (Bell, Bevill); (3) Distribution of radioactivity from 14C and 3H labeled ascorbate in r...

B. M. Tolbert

1967-01-01

139

Toxicity of nickel and silver to Nostoc muscorum: interaction with ascorbic acid, glutathione, and sulfur-containing amino acids  

Energy Technology Data Exchange (ETDEWEB)

Exposure of Nostoc muscorum to different concentrations of Ni and Ag brought about reduction in growth, carbon fixation, heterocyst production, and nitrogenase activity and increase in the loss of ions (K+, Na+). In an attempt to ameliorate the toxicity of test metals by ascorbic acid, glutathione, and sulfur-containing amino acids (L-cysteine and L-methionine), it was found that the level of protection by ascorbic acid and glutathione was more for Ag than Ni. However, metal-induced inhibition of growth and carbon fixation was equally ameliorated by methionine. But the level of protection by cysteine was quite different, i.e., 27% for Ni and 22% for Ag. Protection of metal toxicity in N. muscorum by amino acids lends further support to self-detoxifying ability of cyanobacteria because they are known to synthesize all essential amino acids.

Rai, L.C.; Raizada, M.

1987-08-01

140

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-08-01

 
 
 
 
141

Ascorbic Acid Distribution in Three Introgression Lines of Tomato  

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Full Text Available Total ascorbic acid (total-AsA) content and percentage of reduced ascorbic acid on total-AsA (AsA%) were investigated and discussed in fruits, leaves, petiole, stem and roots of the Solanum lycopersicum cv M82 and S. pennellii introgression lines IL7-3, IL10-1 and IL12-4. In fruits total-AsA content showed to be different according to genotype analysed. Higher total-AsA accumulations was observed for IL7-3 and IL12-4 followed by M82 and IL10-1. Total-AsA was generally higher in leaves than in petioles, stems and roots of all genotypes. In roots higher total-AsA concentration and lower AsA% was generally observed in introgression lines than M82, in particular for IL7-3.

Maria Minutolo; Antonio Di Matteo; Carmine Amalfitano; Antonio Evidente; Luigi Monti; Angela Errico

2010-01-01

142

ASCORBIC ACID, TEREPHTHALATE AND NITROMETHANE STABILIZERS FOR FLUOROOLEFINS  

UK PubMed Central (United Kingdom)

The present disclosure relates to compositions comprising at least one fluoroolefin and an effective amount of a stabilizer comprising at least one ascorbic acid, terephthalate, or nitromethane, or mixtures thereof. The stabilized compositions may be useful in cooling apparatus, such as refrigeration, air-conditioning, chillers and heat pumps, as well as in applications as foam blowing agents, solvents, aerosol propellants, fire extinguishants, and sterilants.

LECK THOMAS J; MINOR BARBARA HAVILAND; NAPPA MARIO JOSEPH; MOULI NANDINI C; HOWELL JON LEE

143

Cosmetic composition comprising ascorbic acid 2-glucoside and ergothioneine  

UK PubMed Central (United Kingdom)

This invention relates to a cosmetic composition allowing the effects of skin aging to be reduced or delayed, comprising as the cosmetically active ingredients ascorbic acid 2-glucoside and ergothioneine. The invention also relates to the use of these cosmetically active ingredients in a cosmetic composition as agents to stimulate DNA repair enzymes, particularly enzymes to repair oxidised DNA bases in dermal and epidermal cells. Finally, the invention relates to a cosmetic treatment process involving this use.

ROBAIN KURFURST; MATHILDE BONNET DUQUENNOY

144

COSMETIC COMPOSITION COMPRISING ASCORBIC ACID 2-GLUCOSIDE AND ERGOTHIONEINE  

UK PubMed Central (United Kingdom)

This invention relates to a cosmetic composition allowing the effects of skin aging to be reduced or delayed, comprising as the cosmetically active ingredients ascorbic acid 2-glucoside and ergothioneine. The invention also relates to the use of these cosmetically active ingredients in a cosmetic composition as agents to stimulate DNA repair enzymes, particularly enzymes to repair oxidised DNA bases in dermal and epidermal cells. Finally, the invention relates to a cosmetic treatment process involving this use.

KURFURST ROBIN; BONNET-DUQUENNOY MATHILDE

145

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

Science.gov (United States)

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

Lugli, S M; Lutz, W K

1999-01-01

146

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

UK PubMed Central (United Kingdom)

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

Lugli SM; Lutz WK

1999-01-01

147

Inhibitory effects of ascorbic acid on the binding of [3H]dopamine antagonists to neostriatal membrane preparations: relationship to lipid peroxidation.  

UK PubMed Central (United Kingdom)

Ascorbic acid, sodium ascorbate, and isoascorbic acid (the stereoisomer of ascorbic acid) inhibited the stereospecific binding of [3H]spiroperidol to neostriatal membrane preparations. Greater inhibitory effects were obtained at intermediate concentrations of the three ascorbic acid analogs (i.e., 0.06 and 0.6 mM) than at higher (6 mM) or lower (0.006 mM) concentrations. In parallel experiments, the three ascorbic acid analogs induced lipid peroxidation, which was also greater at the two intermediate than at higher or lower concentrations. Several known inhibitors of lipid peroxidation, including propyl gallate, butylated hydroxyanisole, butylated hydroxytoluene, alpha-naphthol, and cobalt chloride, as well as the iron chelating agents EDTA and DETAPAC (diethylenetriaminepentaacetic acid) were able to counteract the effects of the ascorbic acid analogs on both lipid peroxidation and on [3H]spiroperidol binding. These data strongly suggest that an iron-catalyzed lipid peroxidation is responsible for the observed inhibitory effects on binding. In other experiments, neostriatal membrane preparations that were preincubated with ascorbic acid (0.6 mM) and subsequently washed still had greatly diminished capacity to bind [3H]spiroperidol, indicating that ascorbic acid need not be physically present during the binding assay in order to affect binding. This experimental procedure also appears to be a way in which [3H]spiroperidol binding sites can be inactivated and washed free of the inactivating agent.

Heikkila RE; Cabbat FS; Manzino L

1982-04-01

148

Pharmacologic doses of ascorbic acid repress specificity protein (Sp) transcription factors and Sp-regulated genes in colon cancer cells.  

UK PubMed Central (United Kingdom)

Ascorbic acid (vitamin C) inhibits cancer cell growth, and there is a controversy regarding the cancer chemoprotective effects of pharmacologic doses of this compound that exhibits prooxidant activity. We hypothesized that the anticancer activity of pharmacologic doses of ascorbic acid (<5 mM) is due, in part, to reactive oxygen species-dependent downregulation of specificity protein (Sp) transcription factors Sp1, Sp3, and Sp4 and Sp-regulated genes. In this study, ascorbic acid (1-3 mM) decreased RKO and SW480 colon cancer cell proliferation and induced apoptosis and necrosis, and this was accompanied by downregulation of Sp1, Sp3, and Sp4 proteins. In addition, ascorbic acid decreased expression of several Sp-regulated genes that are involved in cancer cell proliferation [hepatocyte growth factor receptor (c-Met), epidermal growth factor receptor and cyclin D1], survival (survivin and bcl-2), and angiogenesis [vascular endothelial growth factor (VEGF) and its receptors (VEGFR1 and VEGFR2)]. Other prooxidants such as hydrogen peroxide exhibited similar activities in colon cancer cells, and cotreatment with glutathione inhibited these responses. This study demonstrates for the first time that the anticancer activities of ascorbic acid are due, in part, to ROS-dependent repression of Sp transcription factors.

Pathi SS; Lei P; Sreevalsan S; Chadalapaka G; Jutooru I; Safe S

2011-01-01

149

Ascorbic acid derivatives as a new class of antiproliferative molecules.  

UK PubMed Central (United Kingdom)

Ascorbic acid (AA) has long been described as an antiproliferative agent. However, the molecule has to be used at a very high concentrations, which necessitates i.v. injection, and the tight regulation of in-blood and in-cell AA concentrations making it impossible to hold very high concentrations for any substantial length of time. Here we report evidence that AA derivates are antiproliferative and cytotoxic molecules at an IC50 lower than AA itself. Among these new molecules, we selected K873 that has cytotoxic and antiproliferative effects on different human tumor cells at tenth micromolar concentration. In a further step, we demonstrated that K873 selectively to kills only cancer cells without being toxic for normal non-dividing (or poorly dividing) cells. Finally, we tested the effect of treatment with K873 (5-10mg/kg/d by i.p. route) on tumor progression in xenografted immunodeficient mice (BALB/c Nude). Our data suggest that K873 administration strongly inhibits tumor progression. In a previous study using microarrays, we demonstrated that AA decreases the expression of two genes families involved in cell cycle progression, i.e. initiation factor of translation and tRNA synthetases. Here we show that K873 treatment also decreases the expression of four of these genes in xenografted tumors, in proportions similar to that previously observed with AA. Taken together, our data suggest that AA and K873 share similar action. Our findings suggest that AA derivatives could be a promising new class of anti-cancer drugs, either alone or in combination with other molecules.

Bordignon B; Chiron J; Fontés M

2013-09-01

150

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

International Nuclear Information System (INIS)

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

1987-01-01

151

Effect of L-ascorbic acid on the monophenolase activity of tyrosinase.  

UK PubMed Central (United Kingdom)

The effect of ascorbic acid on the monophenolase activity of tyrosinase, using tyrosine as substrate, has been studied. Over the ranges of ascorbic acid concentration used, no direct effect on the enzyme is found. However, a shortening of the characteristic induction period of the hydroxylation reaction is observed. The evolution of the reaction is dependent on the concentration of ascorbic acid. Low concentrations permit the system to reach the steady state when all ascorbic acid is consumed, whereas high concentrations do not. In the light of these results it is proposed that the influence of ascorbic acid on the reaction is due to its ability to reduce the enzymically generated o-quinones. A relationship between the ascorbic acid concentration, and the induction period generated by it, with the diphenolase activity of tyrosinase is established, which can be used as a basis for the determination of trace amounts of this reducing agent.

Ros JR; Rodríguez-López JN; García-Cánovas F

1993-10-01

152

COSMETIC COMPOSITION FOR SKIN-WHITENING COMPRISING ASCORBIC ACID 2-GLUCOSIDE AND TRICHOLOMA MATSUTAKE EXTRACTS AS ACTIVE INGREDIENTS  

UK PubMed Central (United Kingdom)

PURPOSE: Provided is a cosmetic composition for skin-whitening which comprises ascorbic acid 2-glucoside and Tricholoma matsutake extract as active ingredients. The composition has dramatically increased inhibition effect on tyrosinase activity to show excellent skin whitening effect, and has stability in a formulation. CONSTITUTION: A cosmetic composition for skin-whitening is characterized by containing, as active ingredients, 0.0001-10.0 wt.% of ascorbic acid 2-glucoside and 0.0001-5.0 wt.% of Tricholoma matsutake extract, based on the total dried weight of the composition.

CHO BYEONG GI; JUNG JI HEON; LEE GANG TAE; YOO YEONG GYEONG

153

L-Ascorbic acid and D-isoascorbic acid in a common cold survey.  

UK PubMed Central (United Kingdom)

In a survey of double-bind design, 3 groups of approximately 70 student volunteers took 1 g L-ascorbic acid, 1 g D-isoascorbic acid, or placebo tablets every day for 15 weeks and the incidence and duration of colds were recorded. The group taking D-isoascrobic acid suffered 34% fewer colds than the other two groups; the results were also analyzed in relation to the sex and smoking habits of the volunteers. The rationale for investigating D-isoascorbic acid, an isomer of L-ascorbic acid which has limited antiscorbutic activity, is discussed.

Clegg KM; Macdonald JM

1975-09-01

154

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

UK PubMed Central (United Kingdom)

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.

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

2000-11-01

155

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

Science.gov (United States)

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

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

2000-11-10

156

Study Of Blood Lead Levels, Hemoglobin & Plasma AscorbicAcid In ACarCompanyWelders  

Directory of Open Access Journals (Sweden)

Full Text Available Background and Aims: Background and aim: About 30-40% of lead entered the respiratorysystem, is absorbed to the bloodstream. Some studies have demonstrated that cigarette smokingresults in blood-lead levels elevation as well as decreased blood ascorbic acid. This study hasperformed on this issue in lead exposed welder workers.Method:Adescriptive cross-sectional study was performed to evaluate associations of smokinghabit with blood lead, hemoglobin and plasma ascorbic acid levels in 32 welders. All the casesused to work in a car factory in Tehran suburb as welders 8 hours a day. They were divided intothree groups based on blood lead level quartiles.The blood lead levels were determined by 8003 NAIOSH method and blood ascorbic acid levelwas determined by Lowery method. Results were compared (based on mean values) usingindependent sample t-test and analysis of variance (ANOVA) methods.Results: Results indicated that the blood lead levels in those who smoke 7+ cigarettes per day wassignificantly higher than those who smoke <7 cigarettes per day (p<0.05) or no smoking group(p<0.001). The hemoglobin concentrations in 7+ group was significantly lower than of the <7(p<0.01) and no smoking (p<0.05) groups.Conclusion :Smoking hait in population, who occupationally exposed to lead, causes an increaseexposure to lead and, hence, elevation of blood-lead levels as well as inhibition of hemoglobinsynthesis and therefore reduces hemoglobin concentration.

J Shahrabi; AR Dorosti

2006-01-01

157

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

International Nuclear Information System (INIS)

A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 ?g ml-1. Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C.

1998-01-01

158

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

International Nuclear Information System (INIS)

[en] The present paper shows a systematic dynamic and kinetic study on L-ascorbic acid and its degradation at high temperature. The neutron scattering study allows, through the behavior of quasi-elastic neutron scattering (QENS) spectra, to characterize the diffusive dynamics of L-ascorbic acid in water mixtures. Ascorbic acid undergoes degradation process at high temperature, but the presence of trehalose in solution markedly avoids ascorbic acid loss enhancing its t1/2 (half life time), as determined by high performance liquid chromatography (HPLC)

2008-04-18

159

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

UK PubMed Central (United Kingdom)

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.

Cherdyntseva NV; Ivanova AA; Ivanov VV; Cherdyntsev E; Nair CK; Kagiya TV

2013-07-01

160

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

International Nuclear Information System (INIS)

[en] 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.)

1975-01-01

 
 
 
 
161

Measurement of ascorbic acid and dehydroascorbic acid in gastric juice by HPLC.  

UK PubMed Central (United Kingdom)

New methods are presented for measuring total vitamin C and the ascorbic acid/dehydroascorbic acid ratio in gastric juice. Extracts are prepared from a gastric juice which are suitable for direct injection onto a Waters Nova-pak C18 Radial-pak cartridge for high performance liquid chromatography (HPLC) using ultraviolet absorbance at 270 nm for detection. Both enable removal of interfering mucus and mucopolysaccharide breakdown products in a novel way. The first uses mini-columns of Sephadex G-50, run in acidic conditions to remove large molecular weight material while maintaining the ascorbic acid/dehydroascorbic acid ratio as it was in the fresh sample. Addition of dithiothreitol converts the dehydroascorbic acid quantitatively to ascorbic acid, thus enabling measurement of both components. The second method converts all the dehydroascorbic acid to ascorbic acid at the outset. A perchloric acid extract is neutralized and passed through a Sep-Pak C18. A new internal standard, reductic acid, is introduced for ascorbic acid analysis which behaves identically on Sep-Pak C18. Samples are analysed by ion-pair chromatography using 0.02 M NH4H2PO4 buffer (pH 7.1): methanol (80:20 v/v) containing 0.62 g/L tetrapentylammonium bromide. The detection limit was 1 ng ascorbic acid, and chromatography was completed in 5 min. The values obtained by the two independent HPLC methods were in good agreement with each other and with those obtained by the 2,4-dinitrophenylhydrazine colorimetric method.

Sanderson MJ; Schorah CJ

1987-01-01

162

Measurement of ascorbic acid and dehydroascorbic acid in gastric juice by HPLC.  

Science.gov (United States)

New methods are presented for measuring total vitamin C and the ascorbic acid/dehydroascorbic acid ratio in gastric juice. Extracts are prepared from a gastric juice which are suitable for direct injection onto a Waters Nova-pak C18 Radial-pak cartridge for high performance liquid chromatography (HPLC) using ultraviolet absorbance at 270 nm for detection. Both enable removal of interfering mucus and mucopolysaccharide breakdown products in a novel way. The first uses mini-columns of Sephadex G-50, run in acidic conditions to remove large molecular weight material while maintaining the ascorbic acid/dehydroascorbic acid ratio as it was in the fresh sample. Addition of dithiothreitol converts the dehydroascorbic acid quantitatively to ascorbic acid, thus enabling measurement of both components. The second method converts all the dehydroascorbic acid to ascorbic acid at the outset. A perchloric acid extract is neutralized and passed through a Sep-Pak C18. A new internal standard, reductic acid, is introduced for ascorbic acid analysis which behaves identically on Sep-Pak C18. Samples are analysed by ion-pair chromatography using 0.02 M NH4H2PO4 buffer (pH 7.1): methanol (80:20 v/v) containing 0.62 g/L tetrapentylammonium bromide. The detection limit was 1 ng ascorbic acid, and chromatography was completed in 5 min. The values obtained by the two independent HPLC methods were in good agreement with each other and with those obtained by the 2,4-dinitrophenylhydrazine colorimetric method. PMID:3507237

Sanderson, M J; Schorah, C J

1987-01-01

163

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

UK PubMed Central (United Kingdom)

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

Calero CI; Beltrán González AN; Gasulla J; Alvarez S; Evelson P; Calvo DJ

2013-08-01

164

Improvement of bioavailability for iron from vegetarian meals by ascorbic acid  

International Nuclear Information System (INIS)

[en] 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

1996-01-01

165

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

Science.gov (United States)

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

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

2013-01-01

166

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

UK PubMed Central (United Kingdom)

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

Wang Z; Teng X; Lu C

2012-04-01

167

Synergic interaction between ascorbic acid and antibiotics against Pseudomonas aeruginosa  

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

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

2005-01-01

168

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

2007-01-01

169

Therapeutic efficacy of dimercaptosuccinic acid and thiamine/ascorbic acid on lead intoxication in rats  

Energy Technology Data Exchange (ETDEWEB)

Thiamine, folic acid, pyridoxine and ascorbic acid either individually or in combination have been proven to be effective in reducing the toxic manifestations of lead and in enhancing the antidotal efficacy of CaNa{sub 2}EDTA. In a recent report from the authors' laboratory, it was observed that given combination of thiamine and ascorbic acid with thiol chelators improved the ability of the animals to excrete lead thereby reducing body lead burden. In view of the beneficial effect of these two vitamins, it was considered of interest to evaluate their potential to modify the prophylactic action of DMS in lead intoxication in rat after repeated administration.

Tandon, S.K.; Flora, S.J.S. (Industrial Toxicology Research Centre, Lucknow (India))

1989-11-01

170

Combination, useful e.g. in cosmetic composition to stimulate production of elastin, comprises hydrolyzate of rice protein and at least one monosaccharide derivative of ascorbic acid and a metal salt of phosphorylated ascorbic acid  

UK PubMed Central (United Kingdom)

Combination (I) comprises a hydrolyzate of rice protein and at least one monosaccharide derivative of ascorbic acid and a metal salt of phosphorylated ascorbic acid. - ACTIVITY : Dermatological. - MECHANISM OF ACTION : None given.

PRUNEL ANNE

171

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

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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 ...

Beatriz N. Pirone; Monica R. Ochoa; Alicia G. Kesseler; Antonio De Michelis

172

Low-volume plus ascorbic acid vs high-volume plus simethicone bowel preparation before colonoscopy  

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AIM: To investigate the effectiveness of low-volume plus ascorbic acid [polyethylene glycol plus ascorbic acid (PEG + Asc)] and high-volume plus simethicone [polyethylene glycol plus simethicone (PEG + Sim)] bowel preparations. METHODS: A total of one hundred and forty-four outpatients (76 males), a...

Stefano Pontone; Rita Angelini; Monica Standoli; Gregorio Patrizi; Franco Culasso; Paolo Pontone; Adriano Redler

173

Simultaneous separation and determination of sugars, ascorbic acid and furanic compounds by HPLC - Dual detection  

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An HPLC method was developed for the simultaneous separation and determination of sugars, ascorbic acid, 5-HMF (5-hydroxymethylfurfural), furfural and four other furanic compounds as the possible degradation products of sugars and ascorbic acid on heating and by Maillard reaction. Sucrose, glucose, ...

Yuan, JP; Chen, F

174

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

Science.gov (United States)

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

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

175

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

UK PubMed Central (United Kingdom)

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

De Biaggi CP; Barros PS; Silva VV; Brooks DE; Barros SB

2006-09-01

176

Ascorbic acid metabolism during bilberry (Vaccinium myrtillus L.) fruit development.  

UK PubMed Central (United Kingdom)

Bilberry (Vaccinium myrtillus L.) possesses a high antioxidant capacity in berries due to the presence of anthocyanins and ascorbic acid (AsA). Accumulation of AsA and the expression of the genes encoding the enzymes of the main AsA biosynthetic route and of the ascorbate-glutathione cycle, as well as the activities of the enzymes involved in AsA oxidation and recycling were investigated for the first time during the development and ripening of bilberry fruit. The results showed that the AsA level remained relatively stable during fruit maturation. The expression of the genes encoding the key enzymes in the AsA main biosynthetic route showed consistent trends with each other as well as with AsA levels, especially during the first stages of fruit ripening. The expression of genes and activities of the enzyme involved in the AsA oxidation and recycling route showed more prominent developmental stage-dependent changes during the ripening process. Different patterns of activity were found among the studied enzymes and the results were, for some enzymes, in accordance with AsA levels. In fully ripe berries, both AsA content and gene expression were significantly higher in skin than in pulp.

Cocetta G; Karppinen K; Suokas M; Hohtola A; Häggman H; Spinardi A; Mignani I; Jaakola L

2012-07-01

177

Induction of cell death by ascorbic acid derivatives in human renal carcinoma and glioblastoma cell lines.  

UK PubMed Central (United Kingdom)

Sodium-L-ascorbate, L-ascorbic acid, D-isoascorbic acid, sodium 5,6-benzylidene-L-ascorbate and sodium-6-beta-O-galactosyl-L-ascorbate, which produce ascorbyl radicals during the oxidative degradation, also induced cytotoxicity against cultured human renal carcinoma (TC-1) and glioblastoma multiform tumor (T98G) cell lines. On the other hand, L-ascorbic acid 2-phosphate magnesium and L-ascorbic acid 2-sulfate dipotassium salt, which do not produce the ascorbyl radical, were inactive. This suggests the possible role of the ascorbyl radical for cell death induction. T98G cells were more resistant to ascorbate analogs than TC-1 and HL-60 cells, possibly due to higher intracellular glutathione concentrations. Ascorbate treatment induced rapid elevation of both intracellular concentration of cAMP and Ca2+ in HL-60 cells, but not in TC-1 and T98G cells. However, the elevation of cAMP by theophyline and N,2-dibutyryl adenosine 3,5 cyclic monophosphate (dibutyryl cAMP) resulted in a decrease in the viable cell number. This suggests the possible role of cAMP for ascorbate-induced cell death.

Makino Y; Sakagami H; Takeda M

1999-07-01

178

Induction of cell death by ascorbic acid derivatives in human renal carcinoma and glioblastoma cell lines.  

Science.gov (United States)

Sodium-L-ascorbate, L-ascorbic acid, D-isoascorbic acid, sodium 5,6-benzylidene-L-ascorbate and sodium-6-beta-O-galactosyl-L-ascorbate, which produce ascorbyl radicals during the oxidative degradation, also induced cytotoxicity against cultured human renal carcinoma (TC-1) and glioblastoma multiform tumor (T98G) cell lines. On the other hand, L-ascorbic acid 2-phosphate magnesium and L-ascorbic acid 2-sulfate dipotassium salt, which do not produce the ascorbyl radical, were inactive. This suggests the possible role of the ascorbyl radical for cell death induction. T98G cells were more resistant to ascorbate analogs than TC-1 and HL-60 cells, possibly due to higher intracellular glutathione concentrations. Ascorbate treatment induced rapid elevation of both intracellular concentration of cAMP and Ca2+ in HL-60 cells, but not in TC-1 and T98G cells. However, the elevation of cAMP by theophyline and N,2-dibutyryl adenosine 3,5 cyclic monophosphate (dibutyryl cAMP) resulted in a decrease in the viable cell number. This suggests the possible role of cAMP for ascorbate-induced cell death. PMID:10652601

Makino, Y; Sakagami, H; Takeda, M

179

[The effect of the ascorbic acid-Cu (II) couple on enzyme activity].  

UK PubMed Central (United Kingdom)

Ascorbic acid (AA), Cu (II) and their association affect in different ways the activity of G6P-ase and G6PDH from the rat hepatic cytoplasm enriched in microsomes. G6P-ase is inhibited at a wide range of concentrations: 200-2 mM AA and 1-0.1 mM Cu (II). The association AA-Cu in the above mentioned concentrations, proved to be a stronger inhibitor than AA or Cu (II) introduced separately in the incubation medium. The activity of G6PDH is stimulated by AA-Cu (II) association and inhibited by AA in the dialyzed and nondialyzed cytoplasm. Cu (II) inhibits the activity of G6PDH in the nondialyzed cytoplasm and stimulates it following dialysis. The compounds with recognized antiradical action prove to be inefficient in restoring the activity of G6PDH affected by the AA-Cu (II) association.

Filip M; P?duraru I; Jerca L; Iacobovici A; Saramet A; Filip F

1993-01-01

180

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

UK PubMed Central (United Kingdom)

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

Satyanarayana S; Sushruta K; Sarma GS; Srinivas N; Subba Raju GV

2004-01-01

 
 
 
 
181

Study of Polymorph Prediction For L-Ascorbic Acid  

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

Ali Arslantas; Walter C. Ermler; Rahmi Yazici; Dilhan M. Kalyon

2005-01-01

182

Inherited human collagen lysyl hydroxylase deficiency: ascorbic acid response.  

UK PubMed Central (United Kingdom)

A patient is described with congenital hypotonia, lax joints, friable skin, hemorrhagic scars, high-arched palate, and borderline microcornea. Acid hydrolyzed whole skin collagen had a reduced hydroxylysine content of 0.5 residues per 1,000 as compared to 5.1 +/- 0.7 in control skin. Collagen lysyl hydroxylase in dialyzed subcellular fractions of cultured skin fibroblasts required L-ascorbate as a principal cofactor. Activity of this enzyme in cultured skin fibroblasts derived from this patient, his father, and mother were 17%, 66%, and 39% of control values, respectively. Collagen prolyl hydroxylase activity was normal. Pharmacologic amounts of oral vitamin C (4 gm/day) produced an increase and withdrawal resulted in abrupt diminution of urinary excretion of hydroxylysine. Over a two-year period the patient's wound healing and muscle strength improved and corneal diameter increased. Hydroxylysine content of the skin did not increase.

Elsas LJ 2nd; Miller RL; Pinnell SR

1978-03-01

183

Amperometric biosensor for ascorbic acid/ Biossensor amperométrico para ácido ascórbico  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Desenvolveu-se um biossensor para ácido L-ascórbico empregando ascorbato oxidase. A enzima foi extraída do mesocarpo de pepino com solução tampão fosfato 0,05 mol L-1, pH 5,8 contendo NaCl 0,5 mol L-1. Após diálise versus solução tampão fosfato 0,05 mol L-1, pH 5,8 a enzima foi imobilizada em rede de 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 (more) 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 was 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 (more) 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).

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

2005-01-01

184

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

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

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

2008-01-01

185

Ascorbic acid mediates acetylcholine receptor increase induced by brain extract on myogenic cells.  

UK PubMed Central (United Kingdom)

Extracts of fetal calf brain cause a 3- to 5-fold increase in acetylcholine receptors (AcChoR) on cultured myogenic L5 cells. Purification of the substance causing the major portion of this receptor increase has been completed. Ultraviolet spectral characteristics, nuclear magnetic resonance, mass spectra, and AcChoR induction by the active factor are the same as those of commercially available ascorbic acid. The biological activity of ascorbic acid is not mimicked by reducing agents with or without sulfhydryl groups. Compounds related to ascorbic acid were tested for their ability to induce AcChoR increases on L5 cells. D-Isoascorbic acid is the only substance with identical biological activity to ascorbic acid. Dehydroascorbic acid and ascorbic acid 2-O-sulfate also induce AcChoR increases but with lower specific activity. These data show that ascorbic acid can play a role in regulating AcChoR expression in myogenic tissue, and the presence of ascorbic acid in the purified fraction from fetal calf brain accounts for its ability to increase AcChoR in L5 cells.

Knaack D; Podleski T

1985-01-01

186

Optimal conditions for the simultaneous ion-pairing HPLC determination of L-ascorbic, dehydro-L-ascorbic, D-ascorbic, and uric acids with on-line ultraviolet absorbance and electrochemical detection.  

UK PubMed Central (United Kingdom)

The present report deals with the optimization of a reversed-phase high-performance liquid chromatography (RP-HPLC) method useful for a simultaneous determination of L-ascorbic, isoascorbic, dehydro-L-ascorbic, and uric acids. For this purpose, we investigated (a) the stability of all solutes and especially of L-ascorbic acid under various conditions, (b) the resolution of components of interest by the addition of a positively charged ion-pairing reagent in the mobile phase of different pH levels, and (c) the optimal detection conditions of ascorbate-related compounds. The results demonstrated that L-ascorbic acid remains stable in refrigerated buffer solution of pH 5.0 containing EDTA. A mobile phase of pH 5.0 containing 5 mM cetyltrimethylammonium bromide as an ionic pair offers optimal resolution. The combined use of an ultraviolet (UV) detector and of an electrochemical detector is preferable for the determination of the solutes after reduction of dehydro-L-ascorbic acid to L-ascorbic acid. However, for the direct determination of dehydro-L-ascorbic acid, a previous detection of contents by a UV detector at 232 nm is recommended. The investigation reported here may facilitate future biological studies associated with the determination of L-ascorbic acid and related compounds.

Pappa- Louisi A; Pascalidou S

1998-10-01

187

Optimal conditions for the simultaneous ion-pairing HPLC determination of L-ascorbic, dehydro-L-ascorbic, D-ascorbic, and uric acids with on-line ultraviolet absorbance and electrochemical detection.  

Science.gov (United States)

The present report deals with the optimization of a reversed-phase high-performance liquid chromatography (RP-HPLC) method useful for a simultaneous determination of L-ascorbic, isoascorbic, dehydro-L-ascorbic, and uric acids. For this purpose, we investigated (a) the stability of all solutes and especially of L-ascorbic acid under various conditions, (b) the resolution of components of interest by the addition of a positively charged ion-pairing reagent in the mobile phase of different pH levels, and (c) the optimal detection conditions of ascorbate-related compounds. The results demonstrated that L-ascorbic acid remains stable in refrigerated buffer solution of pH 5.0 containing EDTA. A mobile phase of pH 5.0 containing 5 mM cetyltrimethylammonium bromide as an ionic pair offers optimal resolution. The combined use of an ultraviolet (UV) detector and of an electrochemical detector is preferable for the determination of the solutes after reduction of dehydro-L-ascorbic acid to L-ascorbic acid. However, for the direct determination of dehydro-L-ascorbic acid, a previous detection of contents by a UV detector at 232 nm is recommended. The investigation reported here may facilitate future biological studies associated with the determination of L-ascorbic acid and related compounds. PMID:9799529

Pappa- Louisi, A; Pascalidou, S

1998-10-15

188

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

UK PubMed Central (United Kingdom)

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.

Tanaka M; Muto N; Gohda E; Yamamoto I

1994-12-01

189

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

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

Singh Biswajit K; Bisht Surendra S; Tripathi Rama P

2006-01-01

190

The effects of ascorbic acid on cartilage metabolism in guinea pig articular cartilage explants.  

Science.gov (United States)

Ascorbic acid has been associated with the slowing of osteoarthritis progression in guinea pig and man. The goal of this study was to evaluate transcriptional and translational regulation of cartilage matrix components by ascorbic acid. Guinea pig articular cartilage explants were grown in the presence of L-ascorbic acid (L-Asc), D-isoascorbic acid (D-Asc), sodium L-ascorbate (Na L-Asc), sodium D-isoascorbate (Na D-Asc), or ascorbyl-2-phosphate (A2P) to isolate and analyze the acidic and nutrient effects of ascorbic acid. Transcription of type II collagen, prolyl 4-hydroxylase (alpha subunit), and aggrecan increased in response to the antiscorbutic forms of ascorbic acid (L-Asc, Na L-Asc, and A2P) and was stereospecific to the L-forms. Collagen and aggrecan synthesis also increased in response to the antiscorbutic forms but only in the absence of acidity. All ascorbic acid forms tended to increase oxidative damage over control. This was especially true for the non-nutrient D-forms and the high dose L-Asc. Finally, we investigated the ability of chondrocytes to express the newly described sodium-dependent vitamin C transporters (SVCTs). We identified transcripts for SVCT2 but not SVCT1 in guinea pig cartilage explants. This represents the first characterization of SVCTs in chondrocytes. This study confirms that ascorbic acid stimulates collagen synthesis and in addition modestly stimulates aggrecan synthesis. These effects are exerted at both transcriptional and post-transcriptional levels. The stereospecificity of these effects is consistent with chondrocyte expression of SVCT2, shown previously to transport L-Asc more efficiently than D-Asc. Therefore, this transporter may be the primary mechanism by which the L-forms of ascorbic acid enter the chondrocyte to control matrix gene activity. PMID:11852233

Clark, Amy G; Rohrbaugh, Amy L; Otterness, Ivan; Kraus, Virginia B

2002-03-01

191

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

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

Oveisi MR; Sadeghi N

2001-01-01

192

Erythrocyte defenses against hydrogen peroxide: the role of ascorbic acid.  

UK PubMed Central (United Kingdom)

Ascorbate has been reported to increase intracellular hydrogen peroxide (H2O2) generation in human erythrocytes. In the present work, the basis for this prooxidant effect of the vitamin was investigated in the context of erythrocyte defenses against H2O2. Ascorbate added to erythrocytes caused a dose-dependent increase in intracellular H2O2, which was measured as inactivation of endogenous catalase in the presence of 3-amino-1,2,4-triazole (aminotriazole). Ascorbate-induced catalase inactivation was not observed when only the intracellular ascorbate concentration was increased, when cells were incubated with ascorbate in plasma, or when extracellular Fe3+ was chelated. Together, these results suggest that the observed ascorbate-induced H2O2 generation is due to Fe3+-catalyzed oxidation of extracellular, as opposed to intracellular, ascorbate by molecular oxygen. Rather than generate an oxidant stress in erythrocytes, ascorbate was one of the most sensitive intracellular antioxidants to H2O2 coming from outside the cells. On the other hand, intracellular ascorbate contributed little to the detoxification of H2O2, which was found to be mediated by both catalase and by the GSH system.

Mendiratta S; Qu Z; May JM

1998-05-01

193

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

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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...

Mohamed, H. E.

194

Carbon tetrachloride degradation by alkaline ascorbic acid solution.  

UK PubMed Central (United Kingdom)

Ascorbic acid (AA) mediated electron transfer may induce reductive dechlorination of carbon tetrachloride (CCl(4)). This study investigated the role of AA in conjunction with the presence of iron minerals over a wide pH range for the reduction of CCl(4) in aqueous systems. The results indicate that CCl(4) was reduced by AA at a pH of 13 (>pKa(2, AA) of 11.79) and chloroform (CHCl3) was a transformation byproduct of CCl(4). When CCl(4) levels were reduced to near complete disappearance, the decrease of CHCl(3) was then observed. The degradation rate of CCl(4) and also the formation rate of CHCl(3) increased with increased AA concentrations. Analysis of reaction kinetics between CCl(4) and AA revealed an overall second-order reaction with a rate constant of 0.253 ± 0.018 M(-1) s(-1). Furthermore, the reduction rate of CCl(4) by AA at pH of 13 could be enhanced with the presence of iron minerals (Fe(3)O(4), Fe(2)O(3), FeOOH, and FeS2). In the absence or presence of iron minerals, the fraction of CCl(4) transformed to CHCl(3) was less than 1, indicating simultaneous one- and two-electron transfer processes. The end-products of AA at a pH of 13 included threonic acid and oxalic acid. This study highlights the potential of an alkaline AA solution for remediating chlorinated solvents.

Lin YT; Liang C

2013-04-01

195

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

International Nuclear Information System (INIS)

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

2002-10-15

196

Simple determination of L-ascorbic acid on TLC by visual detection using autocatalytic reaction.  

UK PubMed Central (United Kingdom)

The L-ascorbic acid concentration in beverages was measured after separation by silica gel thin layer chromatography (TLC) by visually determining the time in autocatalytic reaction for the L-ascorbic acid spot to turn the same yellow color of the background and disappear (the end time of the induction period) after spraying the slide with a 3,6-dihydroxyxanthane solution. There was a good linear relationship between the end time of the induction period and the concentration of L-ascorbic acid for concentrations in the range of 5.0 - 20 mM (r(2) = 0.9944). In addition, there was a good relationship expressed by a quadratic equation in the concentration range of 0.1 - 5.0 mM (r(2) = 0.9975). The relative standard deviations of the L-ascorbic acid values for 3 beverages (2.2 - 8.6 mM) were less than 5% (n = 5), and the recovery of 5.0 mM L-ascorbic acid from 4 beverages (0.7 - 7 mM) was 97 - 110%. A good correlation was also observed between the L-ascorbic acid values of 23 beverages (0 - 86 mM) determined by the proposed TLC method and the colorimetric method contained in a commercially available kit for L-ascorbic acid (r(2) = 0.9945).

Akasaka K

2013-01-01

197

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-10-01

198

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

International Nuclear Information System (INIS)

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

2004-01-01

199

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

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

Ali Akbar Aliabadi; Hedayat Sahraei; Mehrangiz Sadooghi; Hasan Ghoshooni; Mehrvaz Alaf-Javadi; Seyed Hasan Salimi; Amir Abbas Barzegari

2006-01-01

200

Hydrophilic interaction liquid chromatography method for the determination of ascorbic acid.  

UK PubMed Central (United Kingdom)

Hydrophilic interaction liquid chromatography (HILIC) method using internal standard for the determination and stability study of ascorbic acid was developed. HILIC method was very fast and simple using the following analytical conditions: ZIC HILIC (150 x 2.1 mm, 3.5 microm) chromatographic column and mobile phase composed of ACN and 50 mM ammonium acetate buffer pH 6.8 (78:22 v/v). Diode array detection was performed and chromatograms were processed at 268 nm, the maximum wavelength of absorbance of ascorbic acid. An extensive stability study of ascorbic acid as a function of various factors including temperature, stabilizing agents, oxygen presence and its concentration in solution was performed in order to gain information about the quantitative influence of individual stability factors. Low temperature and stabilizing agents (o-phosphoric acid and oxalic acid) were found to be key factors enabling substantial enhancement of the stability of ascorbic acid.

Nováková L; Solichová D; Pavlovicová S; Solich P

2008-05-01

 
 
 
 
201

Identification of ascorbic acid and its degradation products in black powder substitutes.  

UK PubMed Central (United Kingdom)

Low explosives such as smokeless powder, black powder, and black powder substitutes have been used in illicit pipe bombings throughout the United States. Some of the newer black powder substitutes are formulated with ascorbic acid, which gradually decomposes as the powder ages, making it difficult if not impossible for the forensic chemist to identify it by traditional bulk techniques. A sensitive method for the identification of residual levels of ascorbic acid in black powder substitutes is presented. Powder samples are extracted with a mixture of acetonitrile and bis(trimethylsilyl)acetamide (BSA), which converts carboxylic acid and alcohol functional groups to trimethylsilyl esters and ethers, respectively. Samples are then analyzed by gas chromatography-mass spectrometry (GC-MS). Results have shown that trace amounts of ascorbic acid can be identified at detection limits that are well below those for traditional bulk techniques. Degradation products for ascorbic acid (hydroxylated carboxylic acids, furanones, and lactones) can also be detected.

Goodpaster JV; Keto RO

2004-05-01

202

Natural origin of ascorbic acid: Validation by ¹³C NMR and IRMS  

UK PubMed Central (United Kingdom)

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 IRMS coupled with gas-chromatography/combustion and elemental analysis devices. The combined use of these techniques enabled us to validate the origins of ascorbic acid batches issuing from different sources.

Albertino Andrea; Barge Alessandro; Cravotto Giancarlo; Genzini Luca; Gobetto Roberto; Vincenti Marco

2009-02-01

203

A postabsorption effect of L-ascorbic acid on copper metabolism in chicks.  

UK PubMed Central (United Kingdom)

We have studied the effect of L-ascorbic acid (vitamin C) on copper metabolism using copper-deficient chicks and the activation of lysyl oxidase copper-dependent enzyme, to assess bioavailability of copper. When administered intraperitoneally with (or 75 minutes before) CuSO4, L-ascorbate significantly impared the effectiveness of copper to restore lysyl oxidase activity in deficient chicks. L-ascorbate given 75 minutes after CuSO4 (i.e., in the post-absorption period), however, produced a substantial increase in copper-induced enzyme activation. L-ascorbate by itself showed no direct stimulating effect in deficient chicks. When the L-ascorbate was given to chicks that had received adequate dietary copper, there was a strong rise in ceruloplasmin and a slight, but significant increase in lysyl oxidase. An increase in ceruloplasmin in response to copper was also seen in deficient chicks and L-ascorbate also augmented that increase. Substituting D-isoascorbic acid for antagonistic properties of L-ascorbic acid on copper metabolism, but they also reveal possible sterospecific postabsorption roles for L-ascorbate in the metabolism of copper.

Disilvestro RA; Harris ED

1981-11-01

204

Ascorbic acid synthesis and metabolism in maize are subject to complex and genotype-dependent feedback regulation during endosperm development.  

Science.gov (United States)

L-ascorbic acid (vitamin C) is an antioxidant and electron donor whose metabolism in plants is under strict feedback control. The factors that influence L-ascorbic acid accumulation in staple crops are only partially understood. One way to gain insight into the regulation of L-ascorbic acid metabolism is to investigate the endogenous pathways in various genetic backgrounds and characterize their interactions with transgenes encoding relevant enzymes. In an initial step, we investigated the developmental profile of L-ascorbic acid accumulation in the endosperm of three diverse maize genotypes and a transgenic line expressing rice dehydroascorbate reductase, which enhances L-ascorbic acid recycling. We determined the transcript levels of all the key genes in the L-ascorbic acid metabolic pathways as well as the specific levels of ascorbic acid and dehydroascorbate. L-ascorbic acid levels were high 20 days after pollination and declined thereafter. We found significant genotype-dependent variations in the transcript levels of some genes, with particular complexity in the ascorbic acid recycling pathway. Our data will help to elucidate the complex mechanisms underlying the regulation of L-ascorbic acid metabolism in plants, particularly the impact of genetic background on the strict regulation of ascorbic acid metabolism in endosperm cells. PMID:23744785

Sanahuja, Georgina; Farré, Gemma; Bassie, Ludovic; Zhu, Changfu; Christou, Paul; Capell, Teresa

2013-07-11

205

Absorption and excretion of ascorbic acid alone and in acerola (Malpighia emarginata) juice: comparison in healthy Japanese subjects.  

Science.gov (United States)

It has been suggested that some food components, such as bioflavonoids, affect the bioavailability of ascorbic acid in humans. Since little is known in Japan about the effective intake of this dietary requirement, we tested young Japanese males after the ingestion of commercial ascorbic acid or acerola (Malpighia emarginata DC.) juice to compare the quantities absorbed and excreted. Healthy Japanese subjects received a single oral dose of ascorbic acid solution (50, 100, 200 or 500 mg) and received distilled water as a reference at intervals of 14 d or longer. All subjects were collected blood and urine until 6 h after ingestion and evaluated for time-dependent changes in plasma and urinary ascorbic acid levels. Predictably, the area under the curve (AUC) values in plasma and urine after ingestion increased dose-dependently. Next, each subject received diluted acerola juice containing 50 mg ascorbic acid. Likewise, their plasma and urinary ascorbic acid concentrations were measured. In plasma, the AUC value of ascorbic acid after ingestion of acerola juice tended to be higher than that from ascorbic acid alone. In contrast, the urinary excretion of ascorbic acid at 1, 2 and 5 h after ingestion of acerola juice were significantly less than that of ascorbic acid. These results indicate that some component of acerola juice favorably affected the absorption and excretion of ascorbic acid. PMID:22040889

Uchida, Eriko; Kondo, Yoshitaka; Amano, Akiko; Aizawa, Shingo; Hanamura, Takayuki; Aoki, Hitoshi; Nagamine, Kenichi; Koizumi, Takeshi; Maruyama, Naoki; Ishigami, Akihito

2011-01-01

206

Absorption and excretion of ascorbic acid alone and in acerola (Malpighia emarginata) juice: comparison in healthy Japanese subjects.  

UK PubMed Central (United Kingdom)

It has been suggested that some food components, such as bioflavonoids, affect the bioavailability of ascorbic acid in humans. Since little is known in Japan about the effective intake of this dietary requirement, we tested young Japanese males after the ingestion of commercial ascorbic acid or acerola (Malpighia emarginata DC.) juice to compare the quantities absorbed and excreted. Healthy Japanese subjects received a single oral dose of ascorbic acid solution (50, 100, 200 or 500 mg) and received distilled water as a reference at intervals of 14 d or longer. All subjects were collected blood and urine until 6 h after ingestion and evaluated for time-dependent changes in plasma and urinary ascorbic acid levels. Predictably, the area under the curve (AUC) values in plasma and urine after ingestion increased dose-dependently. Next, each subject received diluted acerola juice containing 50 mg ascorbic acid. Likewise, their plasma and urinary ascorbic acid concentrations were measured. In plasma, the AUC value of ascorbic acid after ingestion of acerola juice tended to be higher than that from ascorbic acid alone. In contrast, the urinary excretion of ascorbic acid at 1, 2 and 5 h after ingestion of acerola juice were significantly less than that of ascorbic acid. These results indicate that some component of acerola juice favorably affected the absorption and excretion of ascorbic acid.

Uchida E; Kondo Y; Amano A; Aizawa S; Hanamura T; Aoki H; Nagamine K; Koizumi T; Maruyama N; Ishigami A

2011-01-01

207

Ascorbic acid synthesis and metabolism in maize are subject to complex and genotype-dependent feedback regulation during endosperm development.  

UK PubMed Central (United Kingdom)

L-ascorbic acid (vitamin C) is an antioxidant and electron donor whose metabolism in plants is under strict feedback control. The factors that influence L-ascorbic acid accumulation in staple crops are only partially understood. One way to gain insight into the regulation of L-ascorbic acid metabolism is to investigate the endogenous pathways in various genetic backgrounds, and characterize their interactions with transgenes encoding relevant enzymes. In an initial step, we investigated the developmental profile of L-ascorbic acid accumulation in the endosperm of three diverse maize genotypes and a transgenic line expressing rice dehydroascorbate reductase, which enhances L-ascorbic acid recycling. We determined the transcript levels of all the key genes in the L-ascorbic acid metabolic pathways as well as the specific levels of ascorbic acid and dehydroascorbate. L-ascorbic acid levels were high 20 days after pollination and declined thereafter. We found significant genotype-dependent variations in the transcript levels of some genes, with particular complexity in the ascorbic acid recycling pathway. Our data will help to elucidate the complex mechanisms underlying the regulation of L-ascorbic acid metabolism in plants, particularly the impact of genetic background on the strict regulation of ascorbic acid metabolism in endosperm cells.

Sanahuja G; Farré G; Bassie L L; Zhu C; Christou P; Capell T

2013-06-01

208

Structure of ascorbic acid and its biological function. Determination of the conformation of ascorbic acid and isoascorbic acid by infrared and ultraviolet investigations.  

UK PubMed Central (United Kingdom)

The four O-H bands of ascorbic acid could be assigned by means of infrared investigations. It could be shown by electron spin resonance and nuclear magnetic resonance measurements that the radical sodium ascorbate is formed by a cyclic side-chain structure resulting in a loss of C(6)-OH and C(3)-OH. The C(2) = C(3) double bond is still maintained as could be shown by infrared and ultraviolet absorption spectroscopy. In the case of complete oxidation of ascorbic acid to dehydroascorbic acid, C(6)-OH is reestablished (indicating the reopening of the furanoid ring), while C(2)-OH as well as the C(2) = C(3) double bond have disappeared due to the deprotonation of C(2)-OH and C(3)-OH. In the case of isoascorbic acid and its radical potassium isoascorbate similar results are obtained with one distinct difference: in the case of isoascorbic acid, C(2)-OH does not appear while C(3)-OH exhibits a shoulder.

Lohmann W; Pagel D; Penka V

1984-02-01

209

Fluorimetric determination of total ascorbic acid by a stopped-flow mixing technique.  

Science.gov (United States)

A simple, rapid and automatic fluorimetric method for the determination of total ascorbic acid is described. The method makes use of the stopped-flow mixing technique in order to achieve the rapid oxidation of ascorbic acid by dissolved oxygen to dehydroascorbic acid, which then reacts with o-phenylenediamine to form a fluorescent quinoxaline. The initial rate and fluorescence signal of this system are directly proportional to the ascorbic acid concentration. The calibration graph was linear over the range 0.1-30 microg ml(-1) (kinetic method) and 0.25-34 microg ml(-1) (equilibrium method). The precision (% RSD) was close to 0.5%. The method has been used for the determination of ascorbic acid in pharmaceutical formulations, fruit juices, soft drinks and blood serum. PMID:11534621

Pérez-Ruiz, T; Martínez-Lozano, C; Tomás, V; Fenol, J

2001-08-01

210

Fluorimetric determination of total ascorbic acid by a stopped-flow mixing technique.  

UK PubMed Central (United Kingdom)

A simple, rapid and automatic fluorimetric method for the determination of total ascorbic acid is described. The method makes use of the stopped-flow mixing technique in order to achieve the rapid oxidation of ascorbic acid by dissolved oxygen to dehydroascorbic acid, which then reacts with o-phenylenediamine to form a fluorescent quinoxaline. The initial rate and fluorescence signal of this system are directly proportional to the ascorbic acid concentration. The calibration graph was linear over the range 0.1-30 microg ml(-1) (kinetic method) and 0.25-34 microg ml(-1) (equilibrium method). The precision (% RSD) was close to 0.5%. The method has been used for the determination of ascorbic acid in pharmaceutical formulations, fruit juices, soft drinks and blood serum.

Pérez-Ruiz T; Martínez-Lozano C; Tomás V; Fenol J

2001-08-01

211

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

UK PubMed Central (United Kingdom)

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

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

2012-01-01

212

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

Science.gov (United States)

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

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

2012-01-01

213

ISOLATION AND SEQUENCING OF A GENOMIC DNA ENCODING FOR ASCORBATE OXIDASE, A KEY ENZYME INVOLVED IN THE BIODEGRADATION OF ASCORBIC ACID IN MELON  

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A melon genomic library was used to isolate and characterize a clone of genomic DNA coding for ascorbate oxidase (AO) which is considered a key enzyme in the biodegradation of ascorbic acid (AA). The screening of genomic library was performed by using two probes: AO-PCR product and ?E/CMAO3. Seven c...

Evangelos ALATSATIANOS; Marin ARDELEAN; Constantin BOTEZ; Mircea SAVATTI; Radu SESTRA?; Mirela CORDEA

214

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.  

UK PubMed Central (United Kingdom)

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.

Moteki H; Shimamura Y; Kimura M; Ogihara M

2012-05-01

215

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)

2011-01-01

216

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

Directory of Open Access Journals (Sweden)

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

Abbasi; M. Niakousari

2008-01-01

217

On the stability of ascorbic acid in emulsified systems for topical and cosmetic use.  

UK PubMed Central (United Kingdom)

Several O/W microemulsions, O/W and W/O emulsions and a W/O/W multiple emulsion were prepared using non-ionic, non-ethoxylated, skin compatible emulsifiers. Ascorbic acid (vitamin C) was added to the emulsified systems and its stability against oxidation was studied at 45.0 degrees C in aerobic conditions and compared with that in aqueous solutions at different pH values. All emulsified systems provided protection to ascorbic acid, as its degradation rate, which increased with increasing pH, was slower in emulsified systems than in aqueous solutions. The highest protection of ascorbic acid was when it was dissolved in the inner aqueous phase of the W/O/W multiple emulsion, both at 45 and at 20 degrees C for long storage. A pseudo first-order mechanism was hypothesised for ascorbic acid degradation in the experimental conditions for as long as abundant dissolved oxygen was present.

Gallarate M; Carlotti ME; Trotta M; Bovo S

1999-10-01

218

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

Directory of Open Access Journals (Sweden)

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.

Beatriz N. Pirone; Monica R. Ochoa; Alicia G. Kesseler; Antonio De Michelis

2007-01-01

219

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

International Nuclear Information System (INIS)

[en] 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.)

1976-01-01

220

Chemiluminescence flow sensor for the determination of ascorbic acid with immobilized reagents.  

Science.gov (United States)

A novel flow sensor based on chemiluminescence (CL) for the determination of ascorbic acid has been proposed. The analytical reagents, luminol and ferricyanide, were both immobilized on an anion-exchange resin column. The CL signal produced by the reaction between luminol and ferricyanide, which were eluted from the column through sodium phosphate injection, was decreased in the presence of ascorbic acid. The CL emission intensity was linear with ascorbic acid concentration in the range 0.01-0.8 mug ml(-1); the detection limit was 5.5 x 10(-3) mug ml(-1). The whole process, including sampling and washing, could be completed in 1 min with a relative standard deviation of less than 5%. The sensor could be reused more than 100 times and has been applied successfully to the analysis of ascorbic acid in pills and vegetables. PMID:18966471

Zhang, Z; Qin, W

1996-01-01

 
 
 
 
221

Chemiluminescence flow sensor for the determination of ascorbic acid with immobilized reagents.  

UK PubMed Central (United Kingdom)

A novel flow sensor based on chemiluminescence (CL) for the determination of ascorbic acid has been proposed. The analytical reagents, luminol and ferricyanide, were both immobilized on an anion-exchange resin column. The CL signal produced by the reaction between luminol and ferricyanide, which were eluted from the column through sodium phosphate injection, was decreased in the presence of ascorbic acid. The CL emission intensity was linear with ascorbic acid concentration in the range 0.01-0.8 mug ml(-1); the detection limit was 5.5 x 10(-3) mug ml(-1). The whole process, including sampling and washing, could be completed in 1 min with a relative standard deviation of less than 5%. The sensor could be reused more than 100 times and has been applied successfully to the analysis of ascorbic acid in pills and vegetables.

Zhang Z; Qin W

1996-01-01

222

Induction of monozygotic twinning by ascorbic acid in tobacco.  

UK PubMed Central (United Kingdom)

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

Chen Z; Gallie DR

2012-01-01

223

Pediatric reference intervals for lymphocyte vitamin C (ascorbic acid).  

UK PubMed Central (United Kingdom)

OBJECTIVE: To establish pediatric reference intervals for lymphocyte vitamin C. DESIGN AND METHODS: This was a prospective study of 194 well children aged 0-7 years old of mixed ethnicity who had blood drawn for the purpose of this study. Blood was collected during elective surgery under general anesthesia and lymphocytes isolated and stored as frozen ascorbic acid lymphocyte lysates for later HPLC analysis by previously described methodology. Reference intervals were established according to the Clinical and Laboratory Standards Institute (CLSI) and the International Federation of Clinical Chemistry (IFCC) guidelines (C28-A3). Horn-Pesce robust method was used to estimate the 95% confidence interval and 95% reference interval. RESULTS: Reference intervals were independent of age or gender and shown to be 12.9-52.8 ?g/10(8) cells (lymphocytes). CONCLUSION: We have defined pediatric reference ranges for lymphocyte vitamin C in healthy, fasted children at a relevant age group (0-7 years). The new reference interval can now be used to more reliably explore possible implications of variation of vitamin C levels on bleeding and other clinical signs.

Levin A; DeSouza C; Zaarour C; Walsh W; Chan MK; Verjee Z; McIntyre S; Adeli K

2010-12-01

224

Ascorbic acid against reperfusion injury in human renal transplantation.  

Science.gov (United States)

The cadaveric renal graft is exposed to ischaemic injury during preservation and to oxidative damage during reperfusion. Both these mechanisms are known to cause cell damage, which may impair graft function. Reperfusion injury (RPI) is mediated by reactive oxygen species (ROS). Ascorbic acid (AA) is a potent physiological extracellular scavenger of ROS. We perfused 31 renal grafts immediately before implantation with a solution of Euro-Collins containing 0.5 mg/ml of AA to diminish RPI. From every donor, the contralateral kidney served as a control. The control grafts were perfused with the same perfusion as those of the AA group, only without the AA substitution. We assessed the effect of AA by recording serum creatinine, creatinine clearance, initial graft function and early rejections. The incidence of delayed graft function (DGF) was 32% in the AA group, and 29% in the control group. Other parameters were also similar in both groups, except for the length of DGF, which showed a trend towards a shorter duration in the AA group. The pre-operative systemic AA concentration was significantly ( P=0.01) lower in the haemodialysis patients than in those on peritoneal dialysis. In conclusion, this clinical study could not demonstrate significant benefits of AA in renal transplantation. PMID:12719802

Norio, Karri; Wikström, Mårten; Salmela, Kaija; Kyllönen, Lauri; Lindgren, Leena

2003-04-29

225

Skin tumorigenic potential of benzanthrone: Prevention by ascorbic acid.  

Science.gov (United States)

Benzanthrone (BA) exposed occupational workers have been found to exhibit toxicological manifestations in the skin, thus it is quite likely that long term exposure may lead to skin tumorigenicity. Thus, attempts were made to elucidate the tumor initiating and promoting potentials of pure (PBA) and commercial benzanthrone (CBA). Additionally, the preventive role of ascorbic acid (AsA) was also assessed. PBA showed tumor initiating activity while CBA demonstrated tumor initiating as well as promoting activities in two-stage mouse skin tumor protocol. Further, prior treatment of AsA to PBA and CBA followed by twice weekly application of 12-o-tetradecanoyl phorbal myristate acetate (TPA) resulted into delayed onset of tumor formation and similarly single application of 7,12-dimethylbenz [?] anthracene (DMBA) followed by twice weekly application of AsA and CBA showed an increase in the latency period. Thus, AsA showed a protective effect against CBA promoted skin tumor. Furthermore, the topical application of CBA significantly increased the levels of xenobiotic enzymes. The animals topically treated with AsA along with topical application of CBA, restored all the impairment observed in enzyme activities. Thus, this study suggested that AsA can be useful in preventing PBA and CBA induced skin tumorigenicity. PMID:23871828

Dwivedi, Neelam; Kumar, Sandeep; Ansari, Kausar M; Khanna, S K; Das, Mukul

2013-07-16

226

Role of ascorbic acid against pathogenesis in plants  

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

Taqi Ahmed Khan; Mohd Mazid; Firoz Mohammad

2011-01-01

227

Evidence of carrier mediated transport of ascorbic acid through mammalian cornea  

Science.gov (United States)

The purpose of the present study was to evaluate the transport of ascorbic acid, a water soluble molecule, through a predominantly lipophilic cornea. Thus in-vitro permeation of ascorbic acid from aqueous drops through freshly excised mammalian cornea was studied. Aqueous isotonic ophthalmic solutions of ascorbic acid of different concentrations (0.125% w/v to 2% w/v) (pH 5.4) were made. Further 1.0% w/v or 0.5% w/v ascorbic acid solution containing NaCl or dextrose as tonicity modifiers or Na+K+-ATPase inhibitors were also made. Permeation characteristics of drug were evaluated by putting 1 ml formulation on freshly excised cornea fixed between donor and receptor compartments of an all-glass modified Franz diffusion cell and measuring the drug permeated in the receptor by spectrophotometry at 265 nm, after 120 min. Statistical analysis was done by one-way analysis of variance (ANOVA) followed by Dunnett’s test or paired t-test. Increase in drug concentration in the formulation resulted in an increase in the quantity permeated but after a certain level increase in permeation with increase in concentration was minimal. Aqueous drops made isotonic with dextrose showed decreased permeation through paired cornea compared with aqueous drops made isotonic with NaCl from 1% w/v ascorbic acid solution suggesting likely involvement of Na+ co-transporter but there was decreased permeation through 0.5% w/v ascorbic acid solution made isotonic with NaCl as compared to solution made isotonic with dextrose. Further aqueous drops containing Na+K+-ATPase inhibitor {MAG-Mono Ammonium Glycyrrhizinate (25 ?mol)} showed decreased corneal permeation from 0.5% w/v ascorbic acid solution but there was not significant decrease from 1% ascorbic acid solution since MAG is a competitive inhibitor of ascorbic acid. Aqueous drops containing Na+K+-ATPase inhibitor {MAG (50 ?mol) or Ouabain (1 mmol)} showed decreased corneal permeation of ascorbic acid compared with control from 1% ascorbic acid solution confirming the involvement of Na+ co-transporter.

Singla, Shivali; Majumdar, D.K.; Goyal, Sachin; Khilnani, Gurudas

2011-01-01

228

Oxidative stress and innate immunity status in chickens exposed to high dose of ascorbic acid.  

Science.gov (United States)

The effects of high dose ascorbic acid (10?000?mg·kg(-1) in the diet) and the transition metal on the presence of oxidative stress in the internal organs of growing chicks, as well as on the innate immune system status, were investigated. Supplementation with a high dose of ascorbic acid had pro-inflammatory effects on the intestinal mucosa, and lysozyme levels were decreased significantly in all organs studied. High-dose ascorbic acid caused an imbalance between prooxidative and antioxidative activities and was associated with the generation of semiquinone radicals. We observed that ascorbic acid increased iron and cadmium absorption. When a high dose of ascorbic acid was applied, elevated kidney and intestinal mucosa iron concentrations were observed. The amount of free malondialdehyde in the above organs has increased as well. These data have important implications for the mechanism of the oxidative stress development under the influence of high dose of ascorbic acid, indicating the importance of the side reactions of the mitochondrial electron transport chain with the formation of semiquinone radicals and the role of transition metals in this process. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23316001

Berzina, Nadezhda; Markovs, Jurijs; Dizhbite, Tatiana; Apsite, Mirdza; Vasilyeva, Svetlana; Basova, Nataliya; Smirnova, Galina; Isajevs, Sergejs

2013-01-12

229

Formation of furan from carbohydrates and ascorbic acid following exposure to ionizing radiation and thermal processing.  

UK PubMed Central (United Kingdom)

This study was conducted to investigate the formation of furan from sugars, ascorbic acid, and organic acids as affected by ionizing radiation and thermal treatments. Results showed that both thermal treatments and irradiation induced formation of furan from ascorbic acid, fructose, sucrose, or glucose. Little furan was produced from malic acid or citric acid. The pH and concentration of sugars and ascorbic acid solutions had profound influences on furan formation due to either irradiation or thermal treatment. The rate of irradiation-induced furan formation increased with decreasing pH from 8 to 3. Approximately 1600 times less furan was formed at pH 8 as apposed to pH 3. At the same pHs, the amounts of furan formed from irradiation of ascorbic acid, fructose, and sucrose were always higher than from glucose. As pH decreased from 7 to 3, an increase in thermally induced furan was observed for sucrose and ascorbic acid solutions, but for glucose solution, less furan was formed at pH 3 than at pH 7. The levels of sugars commonly found in fruits and fruit juices, upon irradiation, would be high enough to potentially produce low parts per billion (ppb) levels of furan. The concentration of ascorbic acid at which a maximum of furan was produced upon irradiation was about 0.5 mg/mL, a level commonly found in some foods. Five furan derivatives were tentatively identified in thermally treated ascorbic acid solution, while one furan derivative was tentatively found in both irradiated and thermally treated samples.

Fan X

2005-10-01

230

Breaking action of ascorbic acid on nucleic acids.  

UK PubMed Central (United Kingdom)

The lowering of the viscosity of DNA solution was caused by the action of AsA or EA and facilitated in the presence of CU2+. However, the action of AsA-3-P was very weak. By sucrose density gradient centrifugation, it was observed that single- and double-strand scissions of DNA were provoked by AsA or EA and enhanced with Cu2+, while only a single-strand scission was caused by AsA-3-P and Cu2+. Similar action of AsA or AsA-3-P was also observed for RNA. Thus, the result indicates that the enediol group of AsA takes an essential part in the breakage of nucleic acids, and Cu2+ enhances the action. It was shown that Apu was mainly decomposed by AsA, whereas Apy not, suggesting that some pyrimidine cluster may be one of the regions attacked by AsA. During the reaction with DNA, the reducing activity of AsA decreased first to some extent and then increased, whereas the reducing activity of AsA-3-P was much lower than that of AsA and decreased steadily. The priming activity of DNA for DNA polymerase was changed after treatment with AsA according to the condition. It was enhanced when DNA was treated under mild conditions but decreased with severer action.

Omura H; Iiyama S; Tomita Y; Narazaki Y; Shinohara K

1975-01-01

231

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

International Nuclear Information System (INIS)

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

1995-01-01

232

ASCORBIC ACID DERIVATIVES HAVING ALPHA-LIPOYL GROUPS AND PROCESS FOR PREPARING THE SAME  

UK PubMed Central (United Kingdom)

The alpha-lipoic acid-containing ascorbic acid derivative is provided to increase the stability, especially in the aqueous media of ascorbic acid and alpha-lipoic acid, thereby mininizing the denaturation by environments including temperature, light, oxygen and water when it is stored in the aqeous composition for a long time. The alpha-lipoic acid-containing ascorbic acid derivative having improved stability is represented by the chemical formula(1), wherein two of R1 to R4 are hydrogen, one of the remaining radicals is alpha-lipoyl, and the remaining radical is C1-C4 alkyl, CH3CH2O-(CH2CH2O)m-CH2CH2- (M is an integer from 7 to 45), glucosylor C8-C18 acyl.

KIM CHUL HWAN; SHIN CHAN JAE; KO SEUNG HAK

233

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

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

SANUSI Rasaki A.; NWOZOH Sarah; OGUNRO Yetunde

2008-01-01

234

A quick method for the simultaneous determination of ascorbic acid and sorbic acid in fruit juices by capillary zone electrophoresis.  

UK PubMed Central (United Kingdom)

A method of quickly determining ascorbic acid and sorbic acid by capillary zone electrophoresis with ultraviolet detection was developed. The choice of background electrolyte, wavelength, injection time and applied voltage were discussed. Ascorbic acid and sorbic acid were well separated in 80mmolL(-1) boric acid-5mmolL(-1)borax (pH = 8.0) in 5min at the detecting wavelength of 270nm. Under the optimum condition, the method has linear ranges of 2.54-352.00mgL(-1) for ascorbic acid and 1.08-336.39mgL(-1) for sorbic acid with the detection limit of 1.70mgL(-1) for ascorbic acid and 0.54mgL(-1) for sorbic acid, respectively. Other organic acids in fruit juices have no effect on the detection. This method is very feasible and simple and can be used to detect ascorbic acid and sorbic acid in fruit juices.

Tang Y; Wu M

2005-02-01

235

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

International Nuclear Information System (INIS)

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

2004-01-01

236

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

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

Mirsad Salki?; Husejin Keran; Midhat Jaši?

2009-01-01

237

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

Scientific Electronic Library Online (English)

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

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

2008-12-01

238

Loss of L-ascorbic acid in commercial drinking milk caused by milk processing and storage times.  

UK PubMed Central (United Kingdom)

The goals of this study were to determine L-ascorbic acid concentrations in various milk products, and to evaluate the effect of storage time on L-ascorbic acid in milk. Commercial plain milk samples were obtained from either a raw-food market or a supermarket, in Mae Hia, Mueang District, Chiang Mai Province, Thailand, during July, 2008. The types of milk were separated based on fat percentages (non fat-0%, low fat-1.5%, full fat-3%), and their method of processing (pasteurization, UHT). All samples were collected, transported, and measured for their L-ascorbic acid concentrations on the same day. The expiration date, type of milk, and source of milk were recorded. Pasteurized milk had higher L-ascorbic acid levels than UHT milk (p < 0.05), but no differences of L-ascorbic acid levels were seen among the milk fat percentage groups. The L-ascorbic acid level was significantly positively related to time before the expiration date of the milk, indicating that increased storage time of milk is related to decreased L-ascorbic acid concentration in the milk. Longer milk storage times resulted in lower- L-ascorbic acid levels and pasteurized milk has higher L-ascorbic acid levels than UHT milk.

Nalame N; Chaisri W; Suriyasathaporn W

2009-07-01

239

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

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

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

2012-01-01

240

Effect of ascorbic, isoascorbic and dehydroascorbic acids on the growth and survival of Campylobacter jejuni.  

UK PubMed Central (United Kingdom)

Ascorbic acid (AsA), added to nutrient broth at a concentration of 5 mmol/l, was bactericidal towards Campylobacter jejuni grown at 42 degrees C in a micro-aerobic atmosphere. Specific enzymes, radical scavengers, metal chelators and reducing agents were tested as possible antagonists to the cytotoxicity of AsA. The addition of catalase or of the metal chelators ceruloplasmin or Desferal did not prevent the cytotoxic effect of AsA. The addition of the hydroxyl radical scavengers mannitol, formate, histidine or DMSO also failed to counteract the toxicity of AsA. On the other hand, thiourea or cysteamine and the reducing agents cysteine or dithionite significantly increased the recovery of C. jejuni in the presence of AsA. Although the possibility of the involvement of hydroxyl radicals in AsA cytotoxicity cannot be ruled out, it appears that the toxic effect of AsA is due mostly to the formation of products of oxidation of AsA and particularly to dehydroascorbic acid (DHA). Dehydroascorbic acid was also bactericidal to C. jejuni at a concentration of 5 mmol/l. Of all the compounds tested, only cysteamine was effective in preventing (partially) the toxic effect of DHA. The growth of C. jejuni was not inhibited by the addition of 5 mmol/l of isoascorbic acid or sodium isoascorbate.

Juven BJ; Kanner J

1986-10-01

 
 
 
 
241

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

International Nuclear Information System (INIS)

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

2007-01-15

242

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in english OBJECTIVE: Chronic stress has been shown to cause oxidative damage in the central nervous system. Although stress-induced impairments in learning and memory have been studied extensively, very few studies have investigated possible ways to prevent their ill effects. The present work was designed to study the protective effects of ascorbic acid in memory loss induced by chronic restraint stress. METHODS: Adult male Wistar rats were designated into the following groups: (i) (more) 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.

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

2009-01-01

243

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

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

Raju Suresh Kumar; Sareesh Naduvil Narayanan; Satheesha Nayak

2009-01-01

244

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

UK PubMed Central (United Kingdom)

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.

Wallington N; Clark AC; Prenzler PD; Barril C; Scollary GR

2013-12-01

245

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

International Nuclear Information System (INIS)

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

2004-01-01

246

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-11-01

247

Protective effects of ascorbic acid on behavior and oxidative status of restraint-stressed mice.  

UK PubMed Central (United Kingdom)

Studies have demonstrated an association between stressful conditions and the onset of clinical depression. Considering the antidepressant-like properties of ascorbic acid in both experimental and clinical approaches, we evaluated the beneficial effect of this vitamin on restraint stress-induced behavioral and neurochemical alterations. Acute restraint stress caused a depressive-like behavior in the forced swimming test, accompanied by increased lipid peroxidation (cerebral cortex and hippocampus); increased superoxide dismutase (cerebral cortex and hippocampus), glutathione reductase (cerebral cortex), and glutathione peroxidase (cerebral cortex and hippocampus) activities; and elevated expression of Bcl-2 (hippocampus). Oral administration of ascorbic acid (1 mg/kg) or fluoxetine (10 mg/kg) 1 h before restraint stress prevented the stress-induced increase on immobility time in the forced swimming test. Moreover, this vitamin reduced lipid peroxidation to control levels and restored the activity of superoxide dismutase, glutathione reductase, and glutathione peroxidase. Ascorbic acid had no effect on the increased level of Bcl-2 induced by stress. Glutathione levels, glycogen synthase kinase-3? phosphorylation, and Bax expression were not altered by stress or ascorbic acid administration. Besides reinforcing the antioxidant potential of ascorbic acid, our results support the notion that oxidative stress plays a role in the pathogenesis and treatment of stress-induced depression.

Moretti M; Budni J; Dos Santos DB; Antunes A; Daufenbach JF; Manosso LM; Farina M; Rodrigues AL

2013-01-01

248

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

Directory of Open Access Journals (Sweden)

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

Guowei Shu; Hui Yang; Qin Tao; Chen He

2013-01-01

249

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

Science.gov (United States)

The present study investigated the impact of temperature on the degradation of ascorbic acid in low oxygen conditions in a model white wine. The concentrations of ascorbic acid, furfural, sulfur dioxide and phenolic-type products were monitored in a model white wine stored under non-oxidative conditions at 45.0, 36.5 and 24.0°C for up to 693days. 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±3kJ/mol (n=3, standard error). Importantly, these data allow more accurate prediction of the temperature-induced loss of ascorbic acid in low oxygen conditions during transport or storage of wine. PMID:23871070

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

2013-05-31

250

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

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

Nada, H.A. Al- Twaty

2005-01-01

251

Characteristics of ascorbic acid uptake by isolated ox neurohypophyseal nerve terminals and the influence of glucocorticoid and tri-iodothyronine on uptake.  

UK PubMed Central (United Kingdom)

Isolated nerve endings (neurosecretosomes) from ox neurohypophyses took up L-[14C]ascorbic acid by a process or processes which showed energy dependence and which could be inhibited by unlabelled ascorbic acid in micromolar concentrations and by isoascorbic acid in millimolar concentrations, whereas dehydroascorbic acid only inhibited in concentrations of about 100 mM. The uptake showed saturation with increasing concentration of ascorbic acid and a Km value of 97 microM. Uptake was inhibited by increasing glucose concentration in the medium or by adding cytochalasin B, phloridzin, ethanol or probenecid to the medium. The uptake was inhibited by lowering the sodium concentration and by lack of calcium. These facts suggest the presence of both a glucose-dependent uptake and a sodium-dependent uptake. Cortisol and tri-iodothyronine inhibited uptake. This effect of cortisol, but not of tri-iodothyronine, was dependent on the presence of sodium in the medium. For both hormones it was still present when phloridzin or probenecid was added to the medium.

Thorn NA; Nielsen FS; Jeppesen CK

1991-01-01

252

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

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

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

2005-01-01

253

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

Directory of Open Access Journals (Sweden)

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

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

2004-01-01

254

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

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

Mohammad Ali Ghaffari; Samad Mojab

2007-01-01

255

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

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

B.S. Balakumar; R. Suresh; R. Venugopal

2010-01-01

256

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

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

A. Abdollahzadeh; M. Shahedi

2001-01-01

257

Effect of air pollution and other factors on ascorbic acid content of blueberries and lingonberries  

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Blueberries (Vaccinium myrtillus L.) and lingonberries (Vaccinium vitis-idaea L.) were collected on rural and urban forest sites in Finland during the yield periods 1983 and 1984. A major part of the berry material was frozen immediately and analyzed after a shorter or longer storage period. The aim of the study was to simulate the normal use of forest berries and to study the effects of site pollution and other factors on the ascorbic acid content of berries. The ascorbic acid content of blueberries varied from 2.7 mg/100 g frozen berries to 9.9 mg/100 g in 1983 and from 5.0 mg/100 g to 10.9 mg/100 g in 1984. The corresponding values for lingonberries were 5.5 to 13.0 mg in 1983 and 7.3 to 14.1 mg in 1984. The lowest values of the ascorbic acid content of blueberries were obtained for longstored, urban, southern Finnish samples. The corresponding lowest values of lingonberries were obtained for berry samples picked later from industrial sites. The urban and industrial sites, compared to nearby rural ones, had relative mean values for the ascorbic acid content varying from 74% to 112% in blueberries and from 89% to 109% in lingonberries. In urban blue berry sites, the berries generally had a somewhat lower ascorbic acid content during both of the yield periods. Significantly lower values of the ascorbic acid content of blueberries were measured on the urban site in 1984 compared with the rural site during the whole yield period. In blueberries, the effect of freezing was to cause a clear drop in the AA-content level from the fresh value, although after freezing the level remained quite constant.

Huttunen, S.; Karhu, M.

1986-01-01

258

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

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

Barzegari Firouzabadi

2011-01-01

259

Ascorbic acid protects against colistin sulfate-induced neurotoxicity in PC12 cells.  

UK PubMed Central (United Kingdom)

Abstract This study aimed to examine the protective effect of ascorbic acid against colistin-induced neurotoxicity mediated by oxidative stress, a potential mechanism. An in vitro neurotoxicity model was established with PC12 cells exposed to 125 µg/mL colistin sulfate for 24 h. PC12 cells were treated with colistin (125 µg/mL) in the absence and presence of ascorbic acid (0.1, 1.0 and 10µM/mL) for 24h. Both 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) assay were carried out to evaluated cell viability. The levels of intracellular reactive oxygen species (ROS), superoxide dismutase (SOD) and glutathione (GSH) levels were assessed. Moreover, we tested the level of DNA fragmentation, the release of cytochrome-c and the expressions of caspase-9 and -3 mRNA. The results showed that 1 and 10µM/mL ascorbic acid significantly increased the cell viability and the levels of SOD and GSH (both p<0.05), while 0.1,1 and 10µM/mL ascorbic acid significantly decreased generation of ROS, the release of cytochrome-c, formation of DNA fragmentation and the expressions of caspase-9 and -3 mRNA in colistin-treated PC12 cells, compared with the colistin model group. These results suggest that ascorbic acid could reduce colistin sulfate-induced neurotoxicity through the resistance of oxidative stress and the prevention of apoptosis mediated via mitochondoria pathway. They also highlight the potential of coadministering ascorbic acid to widen the therapeutic dose of colistin.

Liu Y; Dai C; Gao R; Li J

2013-05-01

260

Protective role of ascorbic acid in the decontamination of cow milk casein by gamma-irradiation.  

UK PubMed Central (United Kingdom)

PURPOSE: The aim of this work was to investigate the protective role of ascorbic acid on irradiation-induced modification of casein. MATERIALS AND METHODS: Casein stock solutions were irradiated with increasing doses 2-10 kGy using (60)Co Gamma rays at a dose rate D• = 136.73 Gy/min at room temperature. The total viable microorganism content of cow milk casein was evaluated by Plate Count Agar (PCA) incubation for 48 h at 37°C. Sodium dodecylsulfate gel electrophoresis (SDS-PAGE) and Matrix-Assisted Laser Desorption-Ionization Time-of-Flight mass spectrometry (MALDI-TOF-MS) analysis were used to evaluate the effect of gamma irradiation on casein integrity. RESULTS: Gamma irradiation reduced the bacterial contamination of casein solutions at a lower irradiation dose when performed in the presence of ascorbic acid. The irradiation treatment of casein in the absence of ascorbic acid with a dose of 4 kGy could reduce 99% of the original amount of bacterial colonies. However, in the presence of ascorbic acid the irradiation treatment of casein with a dose lower than 2 kGy could reduce 99% of the original amount of bacterial colonies which suggested that the irradiation dose lower than 2 kGy achieved almost the entire decontamination result. SDS-PAGE and MALDI-TOF-MS analysis showed that ascorbic acid protected cow milk casein from degradation and subsequent aggregation probably by scavenging oxygen and protein radicals produced by the irradiation. CONCLUSIONS: It is demonstrated that the combination of gamma irradiation and ascorbic acid produce additive effects, providing acceptable hygienic quality of cow milk casein and protects caseins against Reactive Oxygen Species (ROS) generated, during the irradiation process.

Kouass Sahbani S; Klarskov K; Aloui A; Kouass S; Landoulsi A

2013-06-01

 
 
 
 
261

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

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

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

2012-01-01

262

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

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

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

2012-11-27

263

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

UK PubMed Central (United Kingdom)

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

Montaño A; Sánchez AH; Casado FJ; Beato VM; de Castro A

2013-05-01

264

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.  

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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

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

2012-03-10

265

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

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

1995-01-01

266

Studies on the stability of /sup 3/H-dopamine in neostriatal membrane preparations: effects of ascorbic acid  

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The rate of /sup 3/H-dopamine decomposition was determined in buffers and in neostriatal membrane preparations that are commonly used in binding experiments. The rate of decomposition of /sup 3/H-dopamine was inhibited considerably by the membrane preparation and by ascorbic acid. Under conditions in which the binding of /sup 3/H-dopamine is routinely measured in neostriatal membrane preparations, there was almost no /sup 3/H-dopamine decomposition. The data would seem to suggest that the routine addition of very high concentrations of antioxidants is unnecessary when /sup 3/H-dopamine binding is being determined.

Heikkila, R.E.; Cabbat, F.S.

1983-02-21

267

Mechanism of L-ascorbic acid uptake by rabbit corneal epithelial cells: evidence for the involvement of sodium-dependent vitamin C transporter 2.  

UK PubMed Central (United Kingdom)

PURPOSE: To investigate the mechanism of L-ascorbic acid uptake by rabbit corneal epithelial cells and to functionally characterize the specific transporter involved in this translocation process. METHODS: Uptake studies were carried out with SIRC (Statens Seruminstitut Rabbit Cornea) and rPCEC (rabbit Primary corneal epithelial cell culture) in 12-well plates using [14C] Ascorbic acid (AA). Uptake was done in the presence of L-ascorbic acid and D-isoascorbic acid to delineate stereospecificity. Inhibition studies were performed in the presence of D-glucose a substrate for GLUT and also para amino hippuric acid (PAHA) a substrate for organic anion transporter. Effects of pH and sodium on the uptake of AA were characterized. Concentration dependency studies were performed. Energy dependence of AA uptake was investigated with ouabain and sodium azide in rPCEC. Reverse Transcription-polymerase chain reaction (RT-PCR) was also performed. RESULTS: Uptake of AA was inhibited by about 90% and 50% respectively in the presence of L-ascorbic acid and D-isoascorbic acid in both SIRC and rPCEC. Uptake was unaltered by D-glucose and PAHA. The process was sodium dependent and saturable at higher concentrations. Ouabain and sodium azide significantly diminished the uptake process. It also decreased with a reduction in pH. The RT-PCR results showed the presence of SVCT2 but not SVCT1. CONCLUSIONS: Uptake of AA across rabbit corneal epithelial cells appears to be a carrier mediated active process. A saturable, sodium dependent, and pH sensitive transporter with high specificity for L-ascorbic acid was functionally characterized and was identified as SVCT2.

Talluri RS; Katragadda S; Pal D; Mitra AK

2006-06-01

268

Effect of ascorbic acid on longevity and biochemical alterations in Callosobruchus maculatus F. (Coleoptera: Bruchidae).  

UK PubMed Central (United Kingdom)

Optimal ascorbic acid concentration (1 mM) increased the median (LT(50)) and maximum (LT(100)) life spans, decreased age-independent susceptibility to death (a(0)), reproductive period, number of eggs laid/female but prolonged the post-reproductive period in Callosobruchus maculatus. The activities of respiratory enzymes and the levels of metabolic end-products declined while the activities of antioxygenic enzymes increased. The increased longevity of insects reared on ascorbic acid soaked seeds may be interpreted in terms of conservation of energy by way of decreased reproductive potentiality and the maintenance of a homeostatic balance between pro-oxidant generation and antioxidant defences.

Garg SK; Mahajan S

1994-03-01

269

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

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

Wannee Jiraungkoorskul; Somphong Sahaphong; Piya Kosai; Myung-Huk Kim

2007-01-01

270

FORMULATION CONTAINING STABILIZED ASCORBIC ACID DERIVATIVE FOR SKIN WHITENING AND RELIEVING SKIN STIMULATION  

UK PubMed Central (United Kingdom)

PURPOSE: Provided is a formulation containing a stabilized ascorbic acid derivative for skin whitening and relieving skin stimulation. Therefore, the formulation is effective for pigmentation such as a freckle and a black spot and thus whitens the skin when applied to the skin topically. CONSTITUTION: The formulation for skin cares is characterized by containing 0.1-99.98 wt.% of hydrophilic liquid carrier, 0.01-10 wt.% of a polymeric thickener, 0.01-50 wt.% of ascorbic acid 2-glucoside, and 0.01-20 wt.% of temperantia. Therefore, when it is applied to the skin topically, it has whitening and moderation effects on the skin.

LEE KYUNG ROK

271

Novel 1,2,4-triazole and imidazole derivatives of L-ascorbic and imino-ascorbic acid: synthesis, anti-HCV and antitumor activity evaluations.  

UK PubMed Central (United Kingdom)

Several novel 1,2,4-triazole and imidazole L-ascorbic acid (1, 2, 3, 5, 6 and 9) and imino-ascorbic acid (4, 7 and 8) derivatives were prepared and evaluated for their inhibitory activity against hepatitis C virus (HCV) replication and human tumour cell proliferation. Compounds 6 and 9 exerted the most pronounced cytostatic effects in all tumour cell lines tested, and were highly selective for human T-cell acute lymphoblastic leukaemia cells (CEM/0) with IC(50)s of 10 ± 4 and 7.3 ± 0.1 ?M, respectively. Unlike compound 9, compound 6 showed no toxicity in human diploid fibroblasts. One of the possible mechanisms of action of compound 6 accounting for observed cytostatic activity towards haematological malignancies might be inhibition of inosine monophosphate dehydrogenase (IMPDH) activity, a key enzyme of de novo purine nucleotide biosynthesis providing the cells with precursors for DNA and RNA synthesis indispensable for cell growth and division, which has emerged as an important target for antileukemic therapy. In addition, this compound proved to be the most potent inhibitor of the hepatitis C virus replication as well. However, observed antiviral effect was most likely associated with the effect that the compound exerted on the host cell rather than with selective effect on the replication of the virus itself. In conclusion, results of this study put forward compound 6 as a potential novel antitumor agent (IMPDH inhibitor) for treating leukaemia. Its significant biological activity and low toxicity in human diploid fibroblasts encourage further development of this compound as a lead.

Wittine K; Stipkovi? Babi? M; Makuc D; Plavec J; Kraljevi? Paveli? S; Sedi? M; Paveli? K; Leyssen P; Neyts J; Balzarini J; Mintas M

2012-06-01

272

Novel 1,2,4-triazole and imidazole derivatives of L-ascorbic and imino-ascorbic acid: synthesis, anti-HCV and antitumor activity evaluations.  

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Several novel 1,2,4-triazole and imidazole L-ascorbic acid (1, 2, 3, 5, 6 and 9) and imino-ascorbic acid (4, 7 and 8) derivatives were prepared and evaluated for their inhibitory activity against hepatitis C virus (HCV) replication and human tumour cell proliferation. Compounds 6 and 9 exerted the most pronounced cytostatic effects in all tumour cell lines tested, and were highly selective for human T-cell acute lymphoblastic leukaemia cells (CEM/0) with IC(50)s of 10 ± 4 and 7.3 ± 0.1 ?M, respectively. Unlike compound 9, compound 6 showed no toxicity in human diploid fibroblasts. One of the possible mechanisms of action of compound 6 accounting for observed cytostatic activity towards haematological malignancies might be inhibition of inosine monophosphate dehydrogenase (IMPDH) activity, a key enzyme of de novo purine nucleotide biosynthesis providing the cells with precursors for DNA and RNA synthesis indispensable for cell growth and division, which has emerged as an important target for antileukemic therapy. In addition, this compound proved to be the most potent inhibitor of the hepatitis C virus replication as well. However, observed antiviral effect was most likely associated with the effect that the compound exerted on the host cell rather than with selective effect on the replication of the virus itself. In conclusion, results of this study put forward compound 6 as a potential novel antitumor agent (IMPDH inhibitor) for treating leukaemia. Its significant biological activity and low toxicity in human diploid fibroblasts encourage further development of this compound as a lead. PMID:22555152

Wittine, Karlo; Stipkovi? Babi?, Maja; Makuc, Damjan; Plavec, Janez; Kraljevi? Paveli?, Sandra; Sedi?, Mirela; Paveli?, Krešimir; Leyssen, Pieter; Neyts, Johan; Balzarini, Jan; Mintas, Mladen

2012-02-15

273

Killing of Bacillus subtilis Spores by a Modified Fenton Reagent Containing CuCl2 and Ascorbic Acid  

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Bacillus subtilis spores were killed by CuCl2-ascorbic acid, chloride ions were essential for killing of spores, and spores with defective coats were killed more rapidly. CuCl2-ascorbic acid did not damage spore DNA, and spores killed by this reagent initiated germination. However, spores killed by ...

Shapiro, Michael P.; Setlow, Barbara; Setlow, Peter

274

Ascorbic Acid and Sodium-dependent Vitamin C Transporters in the Peripheral Nervous System: from basic science to clinical trials.  

UK PubMed Central (United Kingdom)

Significance: Ascorbic acid and Sodium-Dependent Vitamin C Transporters (SVCT) have been shown to have important function in the peripheral nervous system (PNS). Ascorbic acid is known to promote myelination in vitro in Schwann cell/dorsal root ganglion co-cultures by the formation of a collagen- and laminin-containing extracellular matrix. Recent Advances: Recently, the function of ascorbic acid and SVCT2 in the PNS has been shown in vivo, as well. Several studies on ascorbic acid treatment of Charcot-Marie-Tooth neuropathy 1A (CMT1A) have been completed and showed no clinical benefit. Critical Issues: Possible reasons for the failure of ascorbic acid in CMT1A treatment are discussed in this review. More preclinical trials, ideally using different animal models, should be considered before initiation of clinical trials in humans. More knowledge about ascorbic acid transport kinetics and inter-individual differences in humans is necessary for future studies. Future Directions: Further research into ascorbic acid transport mechanisms in the PNS is warranted. Especially the effects of transgenic or pharmacologic SVCT2 upregulation on PNS myelination and remyelination will be an interesting area of research in the future. Furthermore, the potential use of ascorbic acid for peripheral neuropathies other than CMT1A would be a possible future research direction.

Gess B; Röhr D; Young P

2013-05-01

275

Use of flavones, flavanones, or flavonoides for the protection of ascorbic acid and/or ascorbylbonds against oxidation  

UK PubMed Central (United Kingdom)

Use of flavone, flavanone or flavonoid compound for protection of ascorbic acid or ascorbyl compound against oxidation, especially in cosmetic and dermatological preparations, Use of a flavone (IA), flavanone (IB) and/or flavonoid (IC) to protect ascorbic acid or ascorbyl compounds against oxidation, including photo-oxidation is claimed.

Kruse Inge; Schönrock Uwe Dr.

276

[Effect of anabolic substances on the state of the individual components of the glutathione-ascorbic acid system  

UK PubMed Central (United Kingdom)

Experiments on rats have shown the lowered content of ascorbic acid in blood and urine during administration of retabolil, nerobol or potassium orotate. Retabolil and potassium orotate increased the content of ascorbic acid in tissues and the content of reduced glutathion in blood. Nerobol produced a rise in vitamin C blood content in the test organs.

Kuzdenbaeva RS; Kurakina VE; Iztleuov MK

1980-09-01

277

Fabrication of multiwalled carbon nanotubes/polyaniline modified Au electrode for ascorbic acid determination.  

UK PubMed Central (United Kingdom)

An ascorbate oxidase (AsOx) (E.C.1.10.3.3) purified from Lagenaria siceraria fruit was immobilized covalently onto a carboxylated multiwalled carbon nanotubes and polyaniline (c-MWCNT/PANI) layer electrochemically deposited on the surface of an Au electrode. The diffusion coefficient of ascorbic acid was determined as 3.05 × 10(-4) cm(2) s(-1). The behavior of different electrolytes on electro-deposition was also studied. An ascorbate biosensor was fabricated using a AsOx/c-MWCNT/PANI/Au electrode as a working electrode, Ag/AgCl (3 M/saturated KCl) as standard and Pt wire as an auxiliary electrode connected through a potentiostat. Linear range, response time and detection limit were 2-206 ?M, 2 s and 0.9 ?M respectively. The biosensor showed optimum response at pH 5.8 and in a broader temperature range (30-45 °C), when polarized at +0.6 V. The biosensor was employed for determination of ascorbic acid level in sera, fruit juices and vitamin C tablets. The sensor was evaluated with 91% recovery of added ascorbic acid in sera and 6.5% and 11.4% within and between batch coefficients of variation respectively for five serum samples. There was a good correlation (r = 0.98) between fruit juice ascorbic acid values by the standard 2,6-dichlorophenolindophenol (DCPIP) method and the present method. The enzyme electrode was used 200 times over a period of two months, when stored at 4 °C. The biosensor has advantages over earlier enzyme sensors in that it has no leakage of enzyme, due to the covalent coupling of enzyme with the support, lower response time, wider working range, higher storage stability and no interference by serum substances.

Chauhan N; Narang J; Pundir CS

2011-05-01

278

Biological nature of the effect of ascorbic acids on the growth of human leukemic cells.  

UK PubMed Central (United Kingdom)

The effects of L-ascorbic acid (LAA) on the in vitro growth of human leukemic colony-forming cells (L-CFC) were analyzed for all acute nonlymphocytic leukemia patients from whom bone marrow aspirates were received by this laboratory for cell culture study. Among 259 cases, 163 could be directly evaluated for LAA effect. L-CFC growth enhancement was noted in 53 (33%) and suppression in 28 (17%), with overall 50% of patients affected by LAA. Among 34 normal bone marrows tested, none were enhanced by LAA while 8 (24%) were suppressed. While caution is needed in interpreting L-CFC suppression by LAA, L-CFC enhancement is clearly significant. Two isomers of LAA, D-isoascorbic acid and D-ascorbic acid, which have weaker antiscorbutic activity than that of LAA, also produced the L-CFC growth-enhancing effect, but to a lesser degree than that of LAA. A dose-response study also substantiated that D-ascorbic acid was definitely less effective than was LAA. Since D-ascorbic acid is the true optical isomer of LAA and has identical physicochemical properties as does LAA, this differential effect is clearly of biological nature. This study indicates that L-CFC growth suppression by LAA is observed in one-sixth of leukemic patients, L-CFC enhancement in one-third of patients, and that L-CFC growth enhancement is a clearly significant finding with a biological mechanism as the basis.

Park CH

1985-08-01

279

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

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

Gamze Erdo?du; Mehmet Mutluhan Mutlu

2011-01-01

280

Ascorbic Acid Metabolism in Pea Seedlings. A Comparison of d-Glucosone, l-Sorbosone, and l-Galactono-1,4-Lactone as Ascorbate Precursors1  

Science.gov (United States)

l-Ascorbic acid (AsA) accumulates in pea (Pisum sativum L.) seedlings during germination, with the most rapid phase of accumulation coinciding with radicle emergence. Monodehydroascorbate reductase and dehydroascorbic acid reductase were active in the embryonic axes before AsA accumulation started, whereas AsA oxidase and AsA peroxidase activities increased in parallel with AsA. Excised embryonic axes were used to investigate the osone pathway of AsA biosynthesis, in which d-glucosone and l-sorbosone are the proposed intermediates. [U-14C]Glucosone was incorporated into AsA and inhibited the incorporation of [U-14C]glucose (Glc) into AsA. A higher d-glucosone concentration (5 mm) inhibited AsA accumulation. l-Sorbosone did not affect AsA pool size but caused a small inhibition in the incorporation of [U-14C]Glc into AsA. Oxidase and dehydrogenase activities capable of converting Glc or Glc-6-phosphate to glucosone were not detected in embryonic axis extracts. The osones are therefore unlikely to be physiological intermediates of AsA biosynthesis. l-Galactono-1,4-lactone, recently proposed as the AsA precursor (G.L. Wheeler, M.A. Jones, N. Smirnoff [1998] Nature 393: 365–369), was readily converted to AsA by pea embryonic axes. Although l-galactono-1,4-lactone did not inhibit [14C]Glc incorporation into AsA, this does not mean that it is not a precursor, because competition between endogenous and exogenous pools was minimized by its very small pool size and rapid metabolism.

Pallanca, Jane E.; Smirnoff, Nicholas

1999-01-01

 
 
 
 
281

Ascorbic acid metabolism in pea seedlings. A comparison of D-glucosone, L-sorbosone, and L-galactono-1,4-lactone as ascorbate precursors  

Science.gov (United States)

L-Ascorbic acid (AsA) accumulates in pea (Pisum sativum L.) seedlings during germination, with the most rapid phase of accumulation coinciding with radicle emergence. Monodehydroascorbate reductase and dehydroascorbic acid reductase were active in the embryonic axes before AsA accumulation started, whereas AsA oxidase and AsA peroxidase activities increased in parallel with AsA. Excised embryonic axes were used to investigate the osone pathway of AsA biosynthesis, in which D-glucosone and L-sorbosone are the proposed intermediates. [U-14C]Glucosone was incorporated into AsA and inhibited the incorporation of [U-14C]glucose (Glc) into AsA. A higher D-glucosone concentration (5 mM) inhibited AsA accumulation. L-Sorbosone did not affect AsA pool size but caused a small inhibition in the incorporation of [U-14C]Glc into AsA. Oxidase and dehydrogenase activities capable of converting Glc or Glc-6-phosphate to glucosone were not detected in embryonic axis extracts. The osones are therefore unlikely to be physiological intermediates of AsA biosynthesis. L-Galactono-1,4-lactone, recently proposed as the AsA precursor (G.L. Wheeler, M.A. Jones, N. Smirnoff [1998] Nature 393: 365-369), was readily converted to AsA by pea embryonic axes. Although L-galactono-1,4-lactone did not inhibit [14C]Glc incorporation into AsA, this does not mean that it is not a precursor, because competition between endogenous and exogenous pools was minimized by its very small pool size and rapid metabolism. PMID:10364396

Pallanca; Smirnoff

1999-06-01

282

Ascorbic acid metabolism in pea seedlings. A comparison of D-glucosone, L-sorbosone, and L-galactono-1,4-lactone as ascorbate precursors  

UK PubMed Central (United Kingdom)

L-Ascorbic acid (AsA) accumulates in pea (Pisum sativum L.) seedlings during germination, with the most rapid phase of accumulation coinciding with radicle emergence. Monodehydroascorbate reductase and dehydroascorbic acid reductase were active in the embryonic axes before AsA accumulation started, whereas AsA oxidase and AsA peroxidase activities increased in parallel with AsA. Excised embryonic axes were used to investigate the osone pathway of AsA biosynthesis, in which D-glucosone and L-sorbosone are the proposed intermediates. [U-14C]Glucosone was incorporated into AsA and inhibited the incorporation of [U-14C]glucose (Glc) into AsA. A higher D-glucosone concentration (5 mM) inhibited AsA accumulation. L-Sorbosone did not affect AsA pool size but caused a small inhibition in the incorporation of [U-14C]Glc into AsA. Oxidase and dehydrogenase activities capable of converting Glc or Glc-6-phosphate to glucosone were not detected in embryonic axis extracts. The osones are therefore unlikely to be physiological intermediates of AsA biosynthesis. L-Galactono-1,4-lactone, recently proposed as the AsA precursor (G.L. Wheeler, M.A. Jones, N. Smirnoff [1998] Nature 393: 365-369), was readily converted to AsA by pea embryonic axes. Although L-galactono-1,4-lactone did not inhibit [14C]Glc incorporation into AsA, this does not mean that it is not a precursor, because competition between endogenous and exogenous pools was minimized by its very small pool size and rapid metabolism.

Pallanca JE; Smirnoff N

1999-06-01

283

Proteomic analysis of strawberry achenes reveals active synthesis and recycling of L-ascorbic acid.  

UK PubMed Central (United Kingdom)

UNLABELLED: Although the commonly named strawberry fruit (Fragaria×ananassa) is the sum of achenes and receptacles, the true fruit in the botanical sense is the achene. Here we report the protein changes occurring in the achene when developing from immature to mature stage. We have used 2-DE followed by image analysis, and protein identification by PMF combined with MS/MS, to investigate the protein variations associated to this transition. From a total of 331 spots analyzed, the corresponding 315 proteins have been identified. Differentially accumulated proteins between immature and mature achenes mostly reflect the physiological events associated to seed development and maturation, with only a few changes related to the development of the dry pericarp. We have focused our attention on vitamin C biosynthesis. Interestingly, GDP-mannose 3',5'-epimerase, a key enzyme in the l-ascorbate biosynthesis pathway, and ascorbate peroxidase, involved in l-ascorbic acid oxidation, accumulate in immature achenes. The higher amount of these enzymes found in the green achene is coincident with a higher content of l-ascorbate, and higher expression levels of these and other gene encoding enzymes of the l-ascorbic acid biosynthesis pathway. Altogether our results suggest an important role of l-ascorbic acid at the early developmental stage of the achene. BIOLOGICAL SIGNIFICANCE: In this manuscript we report the identification of the most abundant proteins in strawberry (F.×ananassa) achenes at early and late stages of development, thus providing a proteomic view of the events that occur during the development of this organ. Despite the importance of strawberry as a commercial fruit, the molecular changes governing its growth and ripening processes are largely unknown. The lack of information is even greater in the case of the achenes, which are the true fruit and play a critical role in the developmental process of the receptacle. Our original proteomic study reported here, restricted to the achenes, completes the previous transcriptomic (very limited) and metabolomic maps of this organ, adding clarity to the role of the achene in the global ripening process. The results obtained not only complement the previous "omics" studies significantly, but also open new key questions that deserve further research (role of hormones). We finally focus on the biosynthesis of l-ascorbic acid, which appears to be tightly regulated by some specific pathways, and whose content is important in the achene. The information provided here will be of interest not only for the groups studying strawberry, but also for many other groups interested in the fruit ripening process, as well as for groups studying the regulation of l-ascorbic acid content in different plant tissues.

Aragüez I; Cruz-Rus E; Botella MÁ; Medina-Escobar N; Valpuesta V

2013-05-01

284

Structure of ascorbic acid and its biological function: V. Transport of ascorbate and isoascorbate across artificial membranes as studied by the spin label technique.  

UK PubMed Central (United Kingdom)

It could be shown by the reduction of the spin label (1,14) located within DPPC vesicles, that Na-ascorbate and K-isoascorbate can permeate membranes. At physiologic pH value, these two compounds exist as electroneutral radicals with a cyclic side chain structure. Ascorbic acid and isoascorbic acid, on the contrary, can hardly permeate such an artificial membrane. Since the radical will cause lipid peroxidation, it must be modified prior to permeation. This can be done by GSH which changes the radical state but maintains the electroneutral bicyclic configuration.

Lohmann W; Winzenburg J

1983-11-01

285

YEAST CELL-WALL PRODUCTS PLUS ASCORBIC ACID: POTENTIAL IMMUNE MODULATORS FOR NEONATAL CALVES  

Science.gov (United States)

Salmonella dublin frequently causes morbidity and mortality in calves during the neonatal period. The objective of this study was to examine the efficacy of ß-glucan with ascorbic acid, for protection against a S. dublin challenge. Thirty-eight calves, 3-10 days-of-age were randomly assigned to: A ...

286

The effect of supplemental ascorbic acid in enriched live food for Clarias gariepinus larvae at startfeeding  

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The effect of three dietary ascorbic acid (AA) concentrations, each applied via two feed types, on production characteristics and physiological condition of African catfish (Clarius gariepinus) larvae has been assessed in two 10-day culture trials. Three treatments received only Artemia

Merchie, G.; Lavens, P.; Verreth, J.; Ollevier, F.P.; Nelis, H.; De Leenheer, A.P.; Storch, V.; Sorgeloos, P.

287

Effective hydrogen generation system by use of ascorbic acid as a reversible electron donor  

Energy Technology Data Exchange (ETDEWEB)

A new hydrogen generating system was discovered, consisting of ZnT/sub SO/sub 3/Na/PP, methyl viologen, colloidal Pt, and ascorbic acid as a reversible electron donor. This system showed a high recycling number for each catalyst involved and a reasonable quantum yield for hydrogen production. The mechanism of the hydrogen-generating reaction is discussed.

Tabushi, I.; Yazaki, A.

1981-04-24

288

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-05-01

289

Minocycline, but not ascorbic acid, increases motor activity and extends the life span of Drosophila melanogaster.  

UK PubMed Central (United Kingdom)

In the present study we compared the effects of minocycline and ascorbic acid in the life span, motor activity and lipid peroxidation of Drosophila melanogaster, in an effort to find a substance capable of providing protection against oxidative stress in aging. In the flies treated with minocycline a very significant increase in the life span (101 +/- 1.33 days) was observed when compared to those treated with ascorbic acid and controls (42.3% and 38.4%, respectively). The motor activity of minocycline treated flies also increased significantly with respect to control and ascorbic acid fed flies, from the 3rd to the 9th week of treatment. With regard to lipid peroxidation, it was found that the levels of malondialdehyde (MDA) in flies treated with minocycline showed no statistical differences to the control on the first day of treatment, but a significantly lower content on the day of 50% survival. In contrast, in flies treated with ascorbic acid significantly elevated levels of MDA compared to control and minocycline treated flies were detected throughout. These results suggest a protective effect of minocycline against oxidative stress and aging in D. melanogaster. An inhibitory effect on reactive oxygen species production may be an important contributing factor.

Mora M; Medina-Leendertz SJ; Bonilla E; Terán RE; Paz MC; Arcaya JL

2013-06-01

290

Solubilization of dipropofol, an antibacterial agent, using saccharide and ascorbic acid.  

UK PubMed Central (United Kingdom)

Dipropofol has a strong antibacterial activity against Gram-positive bacteria. However, it lacked the solubility in water and this property was supposed to limit its efficacy. We tried to improve the solubility and found a new solubilization method of dipropofol in water by the addition of a monosaccharide or ascorbic acid.

Ogata M; Oka K; Seki M; Hoshi M; Takatsu H; Mashino T; Urano S; Endo T

2007-08-01

291

Solubilization of dipropofol, an antibacterial agent, using saccharide and ascorbic acid.  

Science.gov (United States)

Dipropofol has a strong antibacterial activity against Gram-positive bacteria. However, it lacked the solubility in water and this property was supposed to limit its efficacy. We tried to improve the solubility and found a new solubilization method of dipropofol in water by the addition of a monosaccharide or ascorbic acid. PMID:17666822

Ogata, Masahiro; Oka, Kentaro; Seki, Masako; Hoshi, Midori; Takatsu, Hirokatsu; Mashino, Tadahiko; Urano, Shiro; Endo, Toyoshige

2007-08-01

292

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

Directory of Open Access Journals (Sweden)

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

Martín Roberto Alvarez; Fernando Osvaldo Kravetz

2009-01-01

293

Influence of Trace Elements on Stabilization of Aqueous Solutions of Ascorbic Acid  

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Together with vitamin C, zinc, selenium, manganese, and magnesium play a vital role in the preservation of organs scheduled for transplantation. In the present study, it is shown that addition of 1 mg/l of these elements influences the stability of 0.3 mM ascorbic acid solutions. The solution’s stab...

Doli?ska, Barbara; Ostró?ka-Cie?lik, Aneta; Caban, Artur; Rimantas, Klimas; Leszczy?ska, Lucyna; Ryszka, Florian

294

[The effect of topical ascorbic acid application on the healing of rat tympanic membrane perforations].  

UK PubMed Central (United Kingdom)

OBJECTIVES: We investigated the effect of topical administration of ascorbic acid on the healing process of tympanic membrane perforations in rats. DESIGN AND METHODS: Thermal myringotomy was induced in both ears of 22 albino rats. The right and left ears were assigned to topical applications of ascorbic acid and saline solution, respectively. The same procedure was performed after 48 hours. Perforations were examined daily by otomicroscopy and healing periods were determined. For histopathologic examination, a single rat in which closure of the tympanic membranes was not completed was sacrificed on days 5, 7, 10, and 12. Data were analyzed with the use of the Student's t-test. RESULTS: The mean durations of healing in the right and left ears were 7.6 and 8.3 days, respectively. No significant differences were found between the applications of ascorbic acid and saline solution with regard to the duration of closure and histopathologic healing criteria. CONCLUSION: Our data suggest that topical application of ascorbic acid have no beneficial effect on the healing of rat tympanic membrane perforations.

Yi?it O; Cinar U; Co?kun BU; Ba?ak T; Alkan S; Unsal O; Akgül G; Dada? B

2003-07-01

295

Effect of Acridine and Ascorbic Acid on Rhizobia of Legume Trees  

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The present study aimed to induce a great variation exists among Rhizobium spp. that nodulate Leucaena leucocephala and Sesbania sesban, through the treatment with acridine and ascorbic acid and selection of strains for efficiency of the symbiotic association appears possible. B...

El-Adl; Zaied K.A.; Abd El-Wahab; Nassef M.A; E.S. Ibrahim

296

Mutagenicity of Acridine and Ascorbic Acid in Rhizobia of Legume Trees  

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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 i...

M.A. Nassef; A.M. El-Adl; K.A. Zaied; S.M. Abd El-Wahab; E.S. Ibrahim

297

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

Directory of Open Access Journals (Sweden)

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

Samina Malik and Muhammad Ashraf

2012-01-01

298

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

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Vitamin C (l-ascorbic acid; AsA) acts as a potent antioxidant and cellular reductant in plants and animals. AsA has long been known to have many critical physiological roles in plants, yet its biosynthesis is only currently being defined. A pathway for AsA biosynthesis that features GDP-mannose and ...

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

299

Long-distance transport of L-ascorbic acid in potato  

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Abstract Background Following on from recent advances in plant AsA biosynthesis there is increasing interest in elucidating the factors contributing to the L-ascorbic acid (AsA) content of edible crops. One main objective is to establish whether in sink organs such ...

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

300

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

Science.gov (United States)

To improve the Boer goat semen quality during cryopreservation process, three experiments were carried out to investigate the effect of (i) different concentration of ascorbic acid supplementation (ii) rate of cooling with chilled semen characteristics and (iii) method of freezing on post-thaw Boer goat sperm using Tris-based extender. Ascorbic acid at 8.5 mg/ml improved the sperm parameters (motility, integrity of membrane and acrosome, morphology and viability), compared to control in cooled samples (p < 0.05). With regard to other concentrations and post-thawed parameters, ascorbic acid at 2.5-8.5 mg/ml led to higher percentages of sperm motility and integrities of membrane and acrosome when compared to control (p < 0.05). Slow cooling rises to higher percentages of sperm motility, acrosome integrity and viability, in comparison with fast cooling, in terms of cooled and frozen samples (p < 0.05). Programmable freezing method produced the higher percentages of sperm motility, integrities of membrane and acrosome and viability when compared to the freezing method of polystyrene box during goat sperm freezing (p < 0.05). In conclusion, chilled and post-thawed sperm quality of Boer goat was improved when a Tris-based extender supplemented with ascorbic acid was used at stages of different cooling rates and freezing methods. PMID:22909427

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

2012-08-22

 
 
 
 
301

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

Directory of Open Access Journals (Sweden)

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.

Cvetkovi? Biljana R.; Jokanovi? Marija R.

2009-01-01

302

Ascorbic acid treatment enhances would healing in mice exposed to gamma radiation  

International Nuclear Information System (INIS)

The present study was undertaken to investigate the effect of various doses of ascorbic acid on the survival and healing of would in mice whole-body exposed to gamma radiation because of the crucial practical importance of acute radiation exposure associated with combined injuries

2004-01-01

303

Plasma ascorbic acid level and erythrocyte fragility in preeclampsia and eclampsia.  

UK PubMed Central (United Kingdom)

An imbalance between oxidants and antioxidants in the circulation is blamed to cause preeclampsia and eclampsia. In this study plasma ascorbic acid level was analysed in 13 eclamptic, 14 mild preeclamptic, 12 severe preeclamptic and 20 uncomplicated pregnancies to see whether there is any correlation with blood pressure, proteinuria, serum triglyceride level, erythrocyte fragility and leukocyte count. Plasma ascorbic acid level was normal and had no significant difference among the groups. Fasting serum triglyceride level was significantly higher in the study group than in the control group but it did not differ among the three study groups. Erythrocyte fragility was found to be increased in all three study groups. Blood leukocyte count was increased in the study groups, especially in the eclampsia group. However, plasma ascorbic acid level and erythrocyte fragility were found to have no significant correlation with blood pressure and proteinuria. It was concluded that though the ascorbic acid levels were normal in both the study and the control groups, erythrocyte fragility increased probably due to an elevation in peroxide and free radical levels in preeclampsia and eclampsia groups, but without any correlation with the severity of the clinical picture.

Ozan H; Esmer A; Kolsal N; Copur OU; Ediz B

1997-01-01

304

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

2008-01-01

305

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

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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...

Gamze Erdo?du; Mehmet Mutluhan Mutlu

306

Modulator role of ascorbic acid on coniferyl alcohol oxidation by a basic peroxidase from tomato hairy roots  

UK PubMed Central (United Kingdom)

We demonstrated the involvement of a highly basic peroxidase (HBPx) isoenzyme from tomato hairy roots (HR) in the lignosuberization process. In the present study we analysed if it was also involved in the detoxification of H?O? through an ascorbate peroxidase activity (APx) or if AA could affect the coniferyl alcohol peroxidase (CAPx) activity of HBPx, since salt-treated HR grew without browning by oxidation and they were less lignosuberized. The peroxidase isoenzymes from culture medium (CMPx) showed APx activity, however we could not detect oxidation of ascorbic acid (AA) by the purified HBPx. Nevertheless, CAPx activity of the HBPx was inhibited by AA when it was added 1min after the beginning of the reaction. The addition of AA, 1-10?M, produced 20% reduction in CA oxidation while higher concentrations (20-40?M) generated 70-90% CAPx activity inhibition and induced a lag phase. Although apoplastic AA contents were not significantly different between salt-treated and control HR, the AA concentration found in treated tissues (around 17?M) suggests that the participation in the lignosuberization of HBPx would be, at least partially, inhibited under this condition. The effect of AA on HBPx and other peroxidases in relationship with salt-treated HR phenotype is discussed.

Talano MelinaA; Agostini Elizabeth; Wevar Oller AnaL; Medina Mari?aI; Milrad de Forchetti SilviaR

2008-11-01

307

Tear analysis of ascorbic acid, uric acid and malondialdehyde with capillary electrophoresis.  

UK PubMed Central (United Kingdom)

Tears have a significant role in antioxidant defense in ocular tissues and since their collection is quick and noninvasive, their analysis would facilitate monitoring of pathophysiological changes. However, their low volume and low content of antioxidants makes analysis difficult; methods of high sensitivity are needed. In this paper, we present a method for tear analysis of two antioxidant molecules (ascorbic and uric acid) and of a lipid peroxidation indicator (malondialdehyde) with capillary electrophoresis. Tears were collected with Schirmer strips, extracted with a low-pH phosphate buffer, centrifuged through membrane filters and an antioxidant was added. They were stable at -70 degrees C for 15 days. After pilot experiments, optimum electrophoretic separation was achieved in a 25 mM borate buffer, pH 10.0, containing 100 mM sodium dodecyl sulfate at 25 degrees C and 20 kV. The developed method has good repeatability (<5% RSD), precision (<15% relative error values) and high sensitivity (LLOQ values of 20, 2.3 and 2.5 microM for ascorbate, urate and malondialdehyde, respectively). It was applied to the analysis of tears from healthy individuals and the antioxidant levels are in agreement with those obtained with other techniques. This method might serve as a tool to clarify the role of endogenous antioxidants in the pathophysiology of ocular diseases.

Georgakopoulos CD; Lamari FN; Karathanasopoulou IN; Gartaganis VS; Pharmakakis NM; Karamanos NK

2010-08-01

308

Possible warfarin resistance due to interaction with ascorbic acid: case report and literature review.  

UK PubMed Central (United Kingdom)

PURPOSE: A potential interaction involving therapeutic doses of ascorbic acid and warfarin is described. SUMMARY: A 65-year-old Caucasian man with chronic cardiac and pulmonary disorders was admitted to the emergency room for chest pain, shortness of breath, nausea, and diaphoresis. Imaging scans showed acute pulmonary embolism and deep venous thrombosis of the lower extremities. Anticoagulation therapy (enoxaparin 60 mg twice daily) was initiated on the day of admission; warfarin sodium (5 mg daily) was initiated on the next day. After admission to the hospital, the patient continued to use several home medications and vitamins, including ascorbic acid, which he reported taking for three months to facilitate the absorption of oral supplemental iron. For more than a week, his International Normalized Ratio (INR) values remained below target as the dosage of warfarin was gradually increased to 20 mg daily. After potential contributors to warfarin resistance (e.g., impaired liver or renal function, clotting factor abnormalities) were ruled out, ascorbic acid use was discontinued on hospital day 8. The patient's INR rapidly increased to a high of 15.4 on hospital day 10, requiring intervention with phytonadione therapy and the suspension of warfarin use. On day 12, with an INR of 2.7, the patient was restarted on warfarin therapy; he was discharged three days later with stable INR values. CONCLUSION: A patient who was unable to achieve anticoagulation during concurrent treatment with warfarin and ascorbic acid experienced a rapid increase in INR to above-target values after the discontinuation of ascorbic acid use, suggesting that the vitamin might have had an inhibitory effect on warfarin.

Sattar A; Willman JE; Kolluri R

2013-05-01

309

SKIN PERMEATION ENHANCEMENT EFFECTS OF ASCORBIC ACID AND TRIETHYL CITRATE ON ROFECOXIB  

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Full Text Available The enhancing effect of ascorbic acid and triethyl citrate (TEC) on the in vitro skin permeation of rofecoxib across rat epidermis was investigated. Skin pre-treatment with ascorbic acid and TEC at different concentrations, followed by application of rofecoxib gel, showed higher permeation flux than the control condition. The mechanism underlying this permeation enhancement was probed with fourier transform infrared spectroscopy (FTIR). The FTIR spectra of rat epidermis treated with ascorbic acid revealed that ascorbic acid at low concentration appears to interact with dermal keratin, whereas at higher concentration it appears to interact with both dermal proteins and lipids. The FTIR spectra of rat epidermis treated with TEC showed a decrease in peak heights for both asymmetric and symmetric C-H stretching absorbance, indicating a change in the fluidity of alkyl chains in the intercellular lipids in the stratum corneum (SC). The protein disruption effect of TEC was probably due to the solvation of keratin by the formation of hydrogen bonds between TEC hydroxyl groups and keratin chain C=O groups. Skin pre-treatment with different concentrations of permeation enhancers did not show any significant change in lag time in comparison to control. The amount of rofecoxib retained in the skin after skin pre-treatment with enhancers was found to be higher than in the experiment without skin pre-treatment. Scanning electron microscopy (SEM) confirmed the maintenance of skin integrity throughout the permeation experiment. The observed permeation enhancing effects of ascorbic acid and TEC in the present study indicate that a rapid percutaneous absorption of rofecoxib at effective therapeutic levels may facilitate faster anti-inflammatory activity.

MALAY K. DAS; ABDUL B. AHMED

2008-01-01

310

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

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

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

2003-04-01

311

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.

2003-01-01

312

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

UK PubMed Central (United Kingdom)

Ascorbic acid (AA) is a potent antioxidant, and its neuroprotective effect has not been established yet. Using the Rice-Vannucci model, we examined the effect of AA on hypoxic-ischemic (HI) injury in the immature rat brain. Under isoflurane anesthesia, 7-day-old rat pups received 750 mg/kg of AA by intraperitoneal injection just before hypoxic exposure; 8% oxygen for 90 min. Vehicle controls received an equal volume of saline. AA decreased a macroscopic brain injury score at 48 and 168 h post-HI compared with vehicle controls (48 h post-HI, AA 1.38+/-0.45 vs. controls 2.94+/-0.24, p<0.05; 168 h post-HI, 1.13+/-0.44 vs. 2.50+/-0.25, p<0.05). AA injection significantly decreased the number of both necrotic and apoptotic cells in cortex, caudate putamen, thalamus and hippocampus, and also seemed to reduce the number of TUNEL-positive cells. Western blot analysis showed that AA significantly suppressed 150/145 kDa subunits of alpha-fodrin breakdown products (FBDP) in cortex, striatum, thalamus and hippocampus at 24 and 48 h post-HI, and also 120 kDa subunit of FBDP in all examined regions except for thalamus, which indicated that AA injection inhibited both calpain and caspase-3 activation. Western blot analysis of nitrotyrosine failed to show inhibition of free radical production by AA, however, our results show that AA inhibits both necrotic and apoptotic cell death and that AA is neuroprotective after HI in immature rat brain.

Miura S; Ishida-Nakajima W; Ishida A; Kawamura M; Ohmura A; Oguma R; Sato Y; Takahashi T

2009-04-01

313

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

International Nuclear Information System (INIS)

[en] 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

2005-05-30

314

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

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

Al-Rejaie Salim; Abuohashish Hatem; Alkhamees Osama; Aleisa Abdulaziz; Alroujayee Abdulaziz S

2012-01-01

315

In vitro studies of the interaction between ascorbic acid and rat tail tendon.  

UK PubMed Central (United Kingdom)

Ascorbic acid (in its normal and oxidised forms) enhances the mechanical and thermal stability of rat tail tendon. Its effectiveness increases with the concentration but levels off at a value approximately 5 times normal physiological concentration (1--2 mg/100 ml). An analogue, D-isoascorbic acid is also effective, but to a lesser extent. There is some evidence that it reduces reducible aldimine links, especially in young tissues. However, for the most part, its effects are reversible.

Rigby BJ; Mitchell TW

1978-11-01

316

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

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

mehdi abbasnejad; Sima Nasri; Habib Nazem; Mehri Bahaaddini

2008-01-01

317

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

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

Farouk S.

2011-01-01

318

Effect of 3-methylcholanthrene-induced increases in ascorbic acid levels on tissue. beta. -glucuronidase activity in rats  

Energy Technology Data Exchange (ETDEWEB)

The interrelationship between tissue ascorbic acid levels and tissue ..beta..-glucuronidase activity was examined in rats injected with 3-methylcholanthrene, an agent which induces ascorbic acid synthesis in rats. Six Fisher 344 rats were dosed intraperitoneally (IP) with 30 mg/kg of 3-methylcholanthrene. Ascorbic acid levels and ..beta..-glucuronidase (..beta..-G) activity were determined for lung, liver and kidney tissues. In a follow-up study, rats were dosed for three consecutive days with 3-methylcholanthrene. Controls in both groups were dosed IP with Emulphor (EL-620). Animals were sacrificed one week after the final dosage and lung, liver and kidney tissues were examined.

Calabrese, E.J.; Barrett, T.J.; Leonard, D.A.; Horton, H.M.; Kenyon, E.M.

1988-01-01

319

Effect of antioxidants L-ascorbic acid and alpha-tocopherol supplementation in nickel exposed hyperglycemic rats.  

Science.gov (United States)

Nickel-induced hyperglycemia in rats under both acute and subchronic exposure conditions could be due to increased hepatic glycogenolysis, increased pancreatic release of glucagon, decreased peripheral utilization of glucose, or gluconeogenesis. We studied the effect of acute and subchronic nickel sulfate treatment on Wister strain male albino rats simultaneously treated with combined L-ascorbic acid and alpha-tocopherol. The simultaneous treatment with L-ascorbic acid or alpha-tocopherol appears to be beneficial for regulating glucose homeostasis in rats. A significant rise of blood glucose level was also observed with L-ascorbic acid supplementation alone, but not in the case of alpha-tocopherol supplementation alone. PMID:19024927

Tikare, Swati N; Das Gupta, Amrita; Dhundasi, Salim A; Das, Kusal K

2008-01-01

320

Repression of matrix metalloproteinases and inhibition of cell invasion by a nutrient mixture, containing ascorbic acid, lysine, proline, and green tea extract on human fanconi anemia fibroblast cell lines.  

UK PubMed Central (United Kingdom)

AIM: Fanconi Anemia, an autosomal recessive disorder, is characterized by chromosomal abnormality leading to birth defects, progressive bone marrow failure, and a high probability of developing malignancy at an early age. Head and neck squamous cell carcinoma and myeloid leukemia are the major causes of cancer related morbidity and mortality in Fanconi anemia patients. METHODS: We investigated the effect of a nutrient mixture on Fanconi Anemia human fibroblast cell lines FA-A:PD20 and FA-A:PD220 on matrix metalloproteinase expression, invasion, cell proliferation, morphology and apoptosis. The cell lines were grown in a modified Dulbecco's Eagle medium and at near confluence were treated with the nutrient mixture at increasing doses: 0; 10; 50; 100; 500; 1000 µg/ml. The cells were also treated with PMA to induce MMP-9 expression. RESULTS: Zymography demonstrated MMP-2 and PMA-induced MMP-9 activity. The nutrient mixture inhibited expression of both, MMP-2 and MMP-9, in a dose dependent manner with virtually total inhibition observed at 500 µg/ml. Matrigel invasion was inhibited in both cells lines; with 100% inhibition for FA-A:PD20 at 500 µg/ml and 100% inhibition of FA-A:P220 cells at 100 µg/ml. H&E staining did not indicate any change in cell morphology and causes apoptosis at higher doses. CONCLUSION: Our data demonstrated that the nutrient mixture inhibited matrix metalloproteinase expression, invasion and induced apoptosis, the important parameters for cancer prevention. The results suggest that the nutrient mixture may have therapeutic potential in Fanconi Anemia associated neoplasia.

Roomi MW; Roomi NW; Bhanap B; Niedzwiecki A; Rath M

2013-03-01

 
 
 
 
321

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)

2011-01-01

322

Metabolic engineering of Kluyveromyces lactis for L-ascorbic acid (vitamin C) biosynthesis.  

UK PubMed Central (United Kingdom)

BACKGROUND: L-ascorbic acid (L-AA) is naturally synthesized in plants from D-glucose by 10 steps pathway. The pathway branch to synthesize L-galactose, the key intermediate for L-ascorbic acid biosynthesis, has been recently elucidated. Budding yeast produces an 5-carbon ascorbic acid analogue Dehydro-D-arabinono 1,4-lactone (D-DAL), which is synthesized from D-arabinose. Yeast is able to synthesize L-ascorbic acid only if it is cultivated in the presence of one of its precursors: L-galactose, L-galactono 1,4-lactone, or L-gulono 1,4-lactone extracted from plants or animals. To avoid feeding the yeast culture with this "L" enantiomer, we engineered Kluyveromyces lactis with L-galactose biosynthesis pathway genes: GDP-mannose 3,5-epimerase (GME), GDP-L-galactose phosphorylase (VTC2) and L-galactose-1-phosphate phosphatase (VTC4) isolated from Arabidopsis thaliana. RESULTS: Plasmids were constructed and modified such that the cloned plant genes were targeted to the K. lactis LAC4 Locus by homologous recombination and that the expression was associated to the growth on D-galactose or lactose. Upon K. lactis transformation, GME was under the control of the native LAC4 promoter whereas VTC2 and VTC4 were expressed from the S. cerevisiae promoters GPD1 and ADH1 respectively. The expression in K. lactis, of the L-galactose biosynthesis genes was determined by Reverse Transcriptase-PCR and western blotting. The recombinant yeasts were capable to produce about 30 mg.L-1 of L-ascorbic acid in 48 hours of cultivation when cultured on rich medium with 2% (w/v) D-galactose. We also evaluated the L-AA production culturing recombinant recombinant strains in cheese whey, a waste product during cheese production, as an alternative source of lactose. CONCLUSIONS: This work is the first attempt to engineer K. lactis cells for L-ascorbic acid biosynthesis by a fermentation process without any trace of "L" isomers precursors in the culture medium. We have engineered K. lactis strains capable of converting lactose and D-galactose into L-galactose, by the integration of the genes from the A. thaliana L-galactose pathway. L-galactose is a rare sugar, which is one of the main precursors for L-AA production.

Rosa JC; Colombo LT; Alvim MC; Avonce N; Van Dijck P; Passos FM

2013-06-01

323

Ascorbic acid and striatal transport of (/sup 3/H)1-methyl-4-phenylpyridine (MPP/sup +/) and (/sup 3/H)dopamine  

Energy Technology Data Exchange (ETDEWEB)

The inhibition of uptake of (/sup 3/H)dopamine and (/sup 3/H)1-methyl-4-phenylpyridine (MPP/sup +/) was examined in mouse striatal synaptosomal preparations. Kinetic analysis indicated that ascorbic acid is a noncompetitive inhibitor of (/sup 3/H)MPP/sup +/ uptake. No inhibition of (/sup 3/H)dopamine uptake is observed. The dopamine uptake blockers, GBR-12909, cocaine, and mazindol strongly inhibit (IC/sub 50/ < 1 ..mu..M) both (/sup 3/H)dopamine and (/sup 3/H)MPP/sup +/ transport. Nicotine, its metabolites, and other tobacco alkaloids are weak inhibitors except 4-phenylpyridine and lobeline, which are moderate inhibitors of both (/sup 3/H)dopamine and (/sup 3/H)MPP/sup +/ uptake. These similarities in potencies are in agreement with the suggestion that (/sup 3/H)MPP/sup +/ and (/sup 3/H) are transported by the same carrier. The differences observed in the alteration of dopaminergic transport and mazindol binding by ascorbic acid suggest that ascorbic acid's effects on (/sup 3/H)MPP/sup +/ transport are related to translocation and/or dissociation processes occurring subsequent to the initial binding event.

Debler, E.A.; Hashim, A.; Lajtha, A.; Sershen, H.

1988-01-01

324

Mutagenicity of Acridine and Ascorbic Acid in Rhizobia of Legume Trees  

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

M.A. Nassef; A.M. El-Adl; K.A. Zaied; S.M. Abd El-Wahab; E.S. Ibrahim

2002-01-01

325

Effect of Acridine and Ascorbic Acid on Rhizobia of Legume Trees  

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

El-Adl; Zaied K.A.; Abd El-Wahab; Nassef M.A; E.S. Ibrahim

2001-01-01

326

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  

Energy Technology Data Exchange (ETDEWEB)

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.

Mishelevich, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel); Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)], E-mail: apelblat@bgu.ac.il

2008-05-15

327

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.

2008-01-01

328

SO/sub 2/-induced enzymatic changes and ascorbic acid oxidation in Oryza sativa  

Energy Technology Data Exchange (ETDEWEB)

Field grown rice (Oryza sativa L.) plants exposed separately to 0.25 or 0.55 ppm SO/sub 2/ for 1.5 hr daily for 40 days, showed significant decrease of catalase (p<0.001) and increase of peroxidase (p<0.001) activities as well as decreases of protein (p<0.001) and ascorbic acid (p<0.001) contents associated with leaf lesions, which were proportional to SO/sub 2/-dose. Catalase and peroxidase activity levels showed an inverse relationship. It is hypothesized from the molecular structure of both enzymes and from the in vitro relationship between catalase and peroxidase activity that the tetrameric molecules of catalase in vivo might disintegrate into monomeric units with peroxidase activity, which in turn oxidize ascorbic acid and may reduce tolerance of plants to SO/sub 2/.

Nandi, P.K.; Agrawal, M.; Rao, D.N.

1984-01-01

329

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

UK PubMed Central (United Kingdom)

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.

Huang WY; Lee PC; Huang LK; Lu LP; Liao WC

2013-03-01

330

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

Science.gov (United States)

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

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

2013-01-30

331

Efficacy of Ascorbic Acid Reducing Waterborne Copper Toxicity in Butterfish (Poronotus triacanthus)  

Directory of Open Access Journals (Sweden)

Full Text Available This study was investigated the effects of copper (Cu) and Ascorbic Acid (AA) on butterfish (Poronotus triacanthus), using the micronucleus (MN) and Nuclear Abnormality (NA) tests for the period of 7, 14 and 21 days. NA shapes in erythrocytes were scored into blebbed nuclei (BL), lobed nuclei (LB), notched nuclei (NT) and binuclei (BN). It was observed that, fish showed significant sensitivity to the different treatments. In general, the highest value of both MN and NA cells were significantly increased in the Cu treated group followed by the combination of Cu and AA treated group. These values revealed the highest number after 21 days treatment in all cases. The frequencies of each NA shape in erythrocytes of all treatments were observed in the following NT> LB> BN> BL. Present results demonstrated the efficacy of ascorbic acid in reducing genotoxicity in fish induced by waterborne copper.

Wannee Jiraungkoorskul; Somphong Sahaphong

2007-01-01

332

Investigation of thermal decomposition of ascorbic acid by TG-FTIR and thermal kinetics analysis.  

UK PubMed Central (United Kingdom)

The thermal behavior of dry solid ascorbic acid in nitrogen atmosphere in the temperature range of 25-800°C was investigated by TG-FTIR. During the thermal decomposition process, five evolved gaseous species, including H2O, CO2, CO, CH4 and HCOOH, were identified and monitored, in which HCOOH was detected for the first time. The results indicated that ascorbic acid began to decompose at 191°C. Its decomposition process consisted of three stages, and dehydration and decarboxylation to form furfural were the possible principal mechanism. The kinetic analysis for the first decomposition stage was also carried out by the isoconversional method and the master plots method. The results indicated that this process can be described by the model of 1st order reaction.

Jingyan S; Yuwen L; Zhiyong W; Cunxin W

2013-04-01

333

Investigation of thermal decomposition of ascorbic acid by TG-FTIR and thermal kinetics analysis.  

Science.gov (United States)

The thermal behavior of dry solid ascorbic acid in nitrogen atmosphere in the temperature range of 25-800°C was investigated by TG-FTIR. During the thermal decomposition process, five evolved gaseous species, including H2O, CO2, CO, CH4 and HCOOH, were identified and monitored, in which HCOOH was detected for the first time. The results indicated that ascorbic acid began to decompose at 191°C. Its decomposition process consisted of three stages, and dehydration and decarboxylation to form furfural were the possible principal mechanism. The kinetic analysis for the first decomposition stage was also carried out by the isoconversional method and the master plots method. The results indicated that this process can be described by the model of 1st order reaction. PMID:23411004

Jingyan, Shi; Yuwen, Liu; Zhiyong, Wang; Cunxin, Wang

2013-01-20

334

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

Scientific Electronic Library Online (English)

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

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

2012-10-01

335

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

Directory of Open Access Journals (Sweden)

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

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

2012-01-01

336

Rose-hip tea: equilibrium and kinetic study of L-ascorbic acid extraction.  

UK PubMed Central (United Kingdom)

The concentration of L-ascorbic acid (AA) has been measured in aqueous infusions of four different rose-hip teas (Chilean, French, German and Italian) sieved into narrow size ranges. To prevent aerial oxidation the experiments were carried out under anaerobic conditions. The L-ascorbic acid concentrations in the original teas were obtained and correlated with the particle colour, and the AA partition constant was determined at 80 degrees C for the German rose-hip tea. The density of the dry and of the water-swollen German tea was also measured as well as the extent to which it absorbed water. The rate of AA extraction from the various teas was found to decrease with increasing particle size but it showed little variation with temperature from 70 to 90 degrees C or with the pH of the extracting medium. Electron micrographs were taken of several rose-hip tea samples.

Spiro M; Chen SS

1993-01-01

337

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

UK PubMed Central (United Kingdom)

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.

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

1992-08-01

338

Determination of NO/sub 2//sup -//NO/sub 3//sup -/ mixtures by titration with ascorbic acid  

Energy Technology Data Exchange (ETDEWEB)

The analysis of nitrite-nitrate mixtures by indirect titration with ascorbic acid performed before and after passage through a reducing Cd column is proposed and discussed with particular reference to experimental conditions, calculation scheme and concentration ranges.

Campanella, L.; Paoletti, A.M.

1982-01-01

339

Loss of L-ascorbic acid in commercial drinking milk caused by milk processing and storage times.  

Science.gov (United States)

The goals of this study were to determine L-ascorbic acid concentrations in various milk products, and to evaluate the effect of storage time on L-ascorbic acid in milk. Commercial plain milk samples were obtained from either a raw-food market or a supermarket, in Mae Hia, Mueang District, Chiang Mai Province, Thailand, during July, 2008. The types of milk were separated based on fat percentages (non fat-0%, low fat-1.5%, full fat-3%), and their method of processing (pasteurization, UHT). All samples were collected, transported, and measured for their L-ascorbic acid concentrations on the same day. The expiration date, type of milk, and source of milk were recorded. Pasteurized milk had higher L-ascorbic acid levels than UHT milk (p UHT milk. PMID:19842423

Nalame, Nannapat; Chaisri, Wasana; Suriyasathaporn, Witaya

2009-07-01

340

Controlled release of ascorbic acid from gelatin hydrogel attenuates abdominal aortic aneurysm formation in rat experimental abdominal aortic aneurysm model.  

UK PubMed Central (United Kingdom)

CONCLUSIONS: Controlled release of ascorbic acid using gelatin hydrogel sheet-attenuated AAA formation through antioxidant and anti-inflammatory effect, regulation of MMP-2, TIMP-1, and TIMP-2, and preserving elastin and collagen in this animal model.

Tanaka A; Hasegawa T; Morimoto K; Bao W; Yu J; Okita Y; Tabata Y; Okada K

2013-09-01

 
 
 
 
341

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

Directory of Open Access Journals (Sweden)

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

Supranee MANURAKCHINAKORN; Pattama INTAVONG; Pilapa YUENNAN; Salisa TONWATTANA; Amonrat PANKONG

2004-01-01

342

Ascorbic acid status and aflatoxin production in ripe fruits of jujube infected with Aspergillus flavus  

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Full Text Available Although eighteen different fungal species caused postharvest decay of jujube (Ziziphus mauritiana) fruits, only Aspergillus flavus infection was of significance. This post-harvest pathogen not only resulted in maximum loss of ascorbic acid from thefruit tissues but also induced aflatoxin production during pathogenesis. It was noted that approximately 85.7% of the A. flavus isolates associated with jujube decay were toxic.

YASH PAUL SINGH and GEETA SUMBALI

2012-01-01

343

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

International Nuclear Information System (INIS)

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

2013-01-01

344

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

Energy Technology Data Exchange (ETDEWEB)

A spectrophotometric determination of rhenium is based on its reduction with ascorbic acid in the presence of thiocyanate. The orange-yellow complex is extracted into isoamyl alcohol and the absorbance measured at 430 nm. Various foreign ions do not interfere. Molar absorptivity and Sandell's sensitivity are 31162.79 l/mol/cm and 0.0059 [mu]g/cm[sup 2], respectively. (orig.).

Wahi, A.; Kakkar, L.R. (Kurukshetra Univ., Haryana (India). Dept. of Chemistry)

1992-08-01

345

Analysis of ascorbic acid biosynthesis using a simple transient gene expression system in tomato fruit protoplasts.  

UK PubMed Central (United Kingdom)

We established a new method of transient expression using tomato fruit protoplasts. The method showed that L-ascorbic acid (AsA) content in tomato protoplasts was increased by transient expression of the L-galactose-1-phosphate phosphatase gene. This system provides a means of rapid analysis to clarify the function of AsA biosynthetic enzymes and AsA roles in tomato fruit.

Sakamoto S; Fujikawa Y; Esaka M

2013-01-01

346

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

Directory of Open Access Journals (Sweden)

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

B.B.S. Kapoor* and Raksha Mishra

2013-01-01

347

Ascorbic acid reduces the endotoxin-induced lung injury in awake sheep.  

Science.gov (United States)

Our aim was to investigate whether ascorbic acid can reduce reactive oxygen metabolite-mediated acute lung injury. The effects of intravenous administration of Escherichia coli endotoxin were studied, with and without ascorbic acid infusion, on haemodynamics, lung lymph flow, cardio-respiratory and neutrophil function in chronically instrumented sheep. Paired experiments were performed on eight sheep in which they received either endotoxin alone (0.5 micrograms kg-1 b.w.) (ET group) or in combination with an ascorbic acid infusion (1 g kg-1 b.w. bolus injection followed by 0.2 g kg-1 h-1 continuous infusion) ET + ASC group) in random order. Four of the animals also received ascorbic acid alone (ASC group). As a result, for the ET + ASC group a general and mostly significant improvement (P < 0.05) in the early hypertensive phase (0-60 min, P values) and in the late permeability phase (2-4 h, *P values) of cardiorespiratory function (mean artery pressure: P/*P = 0.283/0.049; mean pulmonary artery pressure: P/*P = 0.0001/0.0001; mean pulmonary artery wedge pressure: P/*P = 0.012/0.001; right ventricular stroke work index: P/*P = 0.02/0.0001; cardiac index: P/*P = 0.797/0.755; arterial oxygen saturation: P/*P = 0.0059/0.01; arterial-venous difference of oxygen tension: P/*P = 0.011/0.0005), oxygen consumption: P/*P = 0.013/0.035, lung lymph flow: P/*P = 0.562/0.012, lymph/plasma protein ratio: P/*P = 0.304/0.008 and protein clearance: P/*P = 0.56/0.05 was observed in comparison with the ET group.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8050451

Dwenger, A; Pape, H C; Bantel, C; Schweitzer, G; Krumm, K; Grotz, M; Lueken, B; Funck, M; Regel, G

1994-04-01

348

Potent antioxidant and radical-scavenging activity of Chenpi--compensatory and cooperative actions of ascorbic acid and citric acid.  

UK PubMed Central (United Kingdom)

Dried peels of Satsuma mandarin (Citrus unshiu Marcov.) have been used as traditional Chinese and Japanese medicine, which are called 'Chenpi'. In our present study, cold and hot water extracts of Chenpi exhibited a strong inhibitory activity against linoleic acid peroxidation and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activity compared with o-methanol extract. When these extracts were separated into ethanol-soluble(ES) and ethanol-precipitable fractions, the dominant antioxidant and radical-scavenging activities were detected in the ES fractions, which suggests that these antioxidant and radical-scavenging activities are responsible for water-soluble and low-molecular-weight substances. As possible active principles for antioxidant activities in the water extracts, the contents of ascorbic acid and citric acid in these extracts were measured, and the antioxidant and radical-scavenging activities of these substances were assayed at various concentrations. The experimental results indicate that the antioxidant activity against lipid peroxidation in the water extracts is dominantly associated with citric acid, and the DPPH radical-scavenging activity of the water extracts is majorly responsible for ascorbic acid, suggesting a compensatory action of ascorbic acid and citric acid in expression of the antioxidant and radical-scavenging activities of Chenpi.

Higashi-Okai K; Ishikawa A; Yasumoto S; Okai Y

2009-12-01

349

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

Scientific Electronic Library Online (English)

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

Nelisis Zanoni, Jacqueline; Fernandes Pereira, Renata Virginia

2008-08-01

350

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

Directory of Open Access Journals (Sweden)

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

Jacqueline Nelisis Zanoni; Renata Virginia Fernandes Pereira

2008-01-01

351

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

International Nuclear Information System (INIS)

[en] 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

2006-01-01

352

IMPROVEMENT OF SALT TOLERANCE IN DURUM WHEAT BY ASCORBIC ACID APPLICATION  

Directory of Open Access Journals (Sweden)

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

Fercha Azzedine; Hocine Gherroucha; Mebarek Baka

2011-01-01

353

Influence of trace elements on stabilization of aqueous solutions of ascorbic acid.  

Science.gov (United States)

Together with vitamin C, zinc, selenium, manganese, and magnesium play a vital role in the preservation of organs scheduled for transplantation. In the present study, it is shown that addition of 1 mg/l of these elements influences the stability of 0.3 mM ascorbic acid solutions. The solution's stability was estimated using an accelerated stability test. The concentration of vitamin C was measured using a validated spectrophotometric method, which uses the reduction of 2,6-dichlorophenoloindophenol by ascorbic acid. Elevated temperatures, the factor accelerating substances' decomposition reaction rate, were used in the tests. The research was conducted at two temperatures at intervals of 10 °C: 80?±?0.1 and 90?±?0.1 °C. It was stated that the studied substances' decomposition occurred in accordance with the equation for first-order reactions. The function of the logarithmic concentration (log%C) over time was revealed to be rectilinear. This dependence was used to determine the kinetics of decomposition reaction rate parameters. The stabilization of vitamin C solutions was measured as the time in which 10 % of the substance decomposed at 20 and 0 °C. Addition of Se(IV) or Mg(II) ions significantly increase the stability of ascorbic acid solution (?34 and ?16 %, respectively), but Zn(II) causes a significant decrease in stability by ?23 %. Addition of Mn(II) has no significant influence on vitamin C stability. PMID:23099563

Doli?ska, Barbara; Ostró?ka-Cie?lik, Aneta; Caban, Artur; Rimantas, Klimas; Leszczy?ska, Lucyna; Ryszka, Florian

2012-10-26

354

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-10-15

355

Intravenous ascorbic acid (vitamin C) administration in myomectomy: a prospective, randomized, clinical trial.  

UK PubMed Central (United Kingdom)

BACKGROUND: To assess the usefulness of using ascorbic acid (vitamin C) administration in abdominal myomectomy. MATERIALS AND METHODS: A total of 102 patients were divided two groups in this prospective, clinical trial. Group A had received 2 g of ascorbic acid during a myomectomy, and group B had a myomectomy without any interventions. The operative time, blood loss, days of hospitalization, post-operative complications and rate of blood transfusions were compared between the two groups. RESULTS: The blood loss (521.44 ± 199.24 vs. 932.9 ± 264.38 ml; p value <0.001), duration of the operation time (42 ± 13.9 vs. 68 ± 21.7 min; p value <0.001), days of hospitalization (2.7 ± 0.69 vs. 3.1 ± 0.59 days; p value 0.002) in group A were significantly less than in group B (p value 0.001). The chance risk ratio of a blood transfusion in group A was 0.4 (7.7 vs. 18% 95% CI of 0.1-1; p value 0.07). There was a significant correlation between the volume of bleeding and post-operative complications in both groups (p value in group A = 0.03; in group B = 0.004). CONCLUSION: The administration of ascorbic acid (vitamin C) in abdominal myomectomy could reduce the blood loss during the procedure, operation time and days of hospitalization.

Pourmatroud E; Hormozi L; Hemadi M; Golshahi R

2012-01-01

356

Decylglucoside-based microemulsions for cutaneous localization of lycopene and ascorbic acid.  

UK PubMed Central (United Kingdom)

Cutaneous delivery of combinations of antioxidants offers the possibility of enhanced protection against UV-radiation. In this study, we investigated the potential of sugar-based microemulsions containing monoglycerides to promote simultaneous cutaneous delivery of lycopene and ascorbic acid, and increase tissue antioxidant activity. Lycopene and ascorbic acid were incorporated (0.04% and 0.2% (w/w), respectively) in decylglucoside-based microemulsions containing isopropyl myristate mixed with monocaprylin (ME-MC), monolaurin (ME-ML) or monoolein (ME-MO) as oil phase. The microemulsions increased lycopene delivery into porcine ear skin by 3.3- to 8-fold compared to a drug solution. The effect of microemulsions on ascorbic acid cutaneous delivery was more modest (1.5-3-fold), and associated with an approximately 2-fold increase in transdermal delivery. According to their penetration-enhancing ability, the microemulsions were ranked ME-MC>ME-MO>ME-ML. This superiority of ME-MC coincided with a stronger effect in decreasing skin electrical resistance. After 18 h of treatment, the viability of bioengineered skin treated with ME-MC was 2.2-times higher compared to Triton-X100 (moderate irritant), demonstrating that ME-MC is less cytotoxic. Skin treatment with ME-MC containing both antioxidants increased the tissue antioxidant activity by 10.2-fold, but no synergism between the antioxidants was observed.

Pepe D; Phelps J; Lewis K; Dujack J; Scarlett K; Jahan S; Bonnier E; Milic-Pasetto T; Hass MA; Lopes LB

2012-09-01

357

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)

1994-01-01

358

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)

2009-01-01

359

Genotoxicity and oxidative stress of microwave radiation role of ascorbic acid  

International Nuclear Information System (INIS)

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

2005-01-01

360

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

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

 
 
 
 
361

Endothelial nitric oxide synthase activity involves in the protective effect of ascorbic acid against penicillin-induced epileptiform activity.  

UK PubMed Central (United Kingdom)

Ascorbic acid and nitric oxide are known to play important roles in epilepsy. The aim of present study was to identify the involvement of nitric oxide (NO) in the anticonvulsant effects of ascorbic acid on penicillin-induced epileptiform activity in rats. Intracortical injection of penicillin (500, International Units (IU)) into the left sensorimotor cortex induced epileptiform activity within 2-5 min. Thirty minutes after penicillin injection, nitric oxide synthase (NOS) inhibitor, N(G)-nitro-l-arginine methyl ester (l-NAME, 100mg/kg), neuronal nitric oxide synthase (nNOS) inhibitor 7-nitroindazole (7-NI, 40 mg/kg), NO substrate, l-arginine (500 mg/kg) were administered with the most effective dose of ascorbic acid (100 mg/kg) intraperitoneally (i.p.). The administration of l-arginine significantly decreased the frequency of epileptiform activity while administration of l-NAME did not influence the mean frequency of epileptiform activity. Injection of 7-NI decreased the mean frequency of epileptiform activity but did not influence amplitude. Ascorbic acid decreased both the mean frequency and amplitude of penicillin-induced epileptiform activity in rats. The application of l-NAME partially and temporarily reversed the anticonvulsant effects of ascorbic acid. The results support the hypothesis of neuro-protective role for NO and ascorbic acid. The protective effect of ascorbic acid against epileptiform activity was partially and temporarily reversed by nonspecific nitric oxide synthase inhibitor l-NAME, but not selective neuronal nitric oxide synthase inhibitor 7-NI, indicating that ascorbic acid needs endothelial-NOS/NO route to decrease penicillin-induced epileptiform activity.

Yildirim M; Ayyildiz M; Agar E

2010-03-01

362

Epimeric separation of L-ascorbic acid and D-isoascorbic acid by capillary zone electrophoresis.  

UK PubMed Central (United Kingdom)

Capillary zone electrophoresis (CZE) was used for separation of L-ascorbic acid (L-AA) and D-isoascorbic acid (D-IAA) in a model system. The effects of borate buffer concentration (0.05-0.25 M) and pH (pH 7.5-9.0) on migration time, resolution (Rs), and theoretical plates (N) were investigated. The migration times of L-AA and D-IAA increased with the increasing pH of carrier electrolyte (0.2 borate buffer), and the resolutions (Rs) of L-AA and D-IAA were calculated to be 12.98 at pH 9.0. Concentrations of borate buffer (pH 9.0) increased the Rs values of L-AA and D-IAA, and buffer concentrations >0.1 M were found to be effective for separation of L-AA and D-IAA. Methanol in the carrier electrolyte was also influential in improving the separation of L-AA and D-IAA, which increased with the increasing concentrations (0-10%) of methanol. The optimal separation conditions for L-AA and D-IAA were as follows: carrier electrolyte, 0.2 M borate buffer (pH 9.0); applied voltage, 25 kV, with an uncoated fused silica capillary, 75 microm (i.d.) x 57 cm.

Liao T; Wu JS; Wu MC; Chang HM

2000-01-01

363

Epimeric separation of L-ascorbic acid and D-isoascorbic acid by capillary zone electrophoresis.  

Science.gov (United States)

Capillary zone electrophoresis (CZE) was used for separation of L-ascorbic acid (L-AA) and D-isoascorbic acid (D-IAA) in a model system. The effects of borate buffer concentration (0.05-0.25 M) and pH (pH 7.5-9.0) on migration time, resolution (Rs), and theoretical plates (N) were investigated. The migration times of L-AA and D-IAA increased with the increasing pH of carrier electrolyte (0.2 borate buffer), and the resolutions (Rs) of L-AA and D-IAA were calculated to be 12.98 at pH 9.0. Concentrations of borate buffer (pH 9.0) increased the Rs values of L-AA and D-IAA, and buffer concentrations >0.1 M were found to be effective for separation of L-AA and D-IAA. Methanol in the carrier electrolyte was also influential in improving the separation of L-AA and D-IAA, which increased with the increasing concentrations (0-10%) of methanol. The optimal separation conditions for L-AA and D-IAA were as follows: carrier electrolyte, 0.2 M borate buffer (pH 9.0); applied voltage, 25 kV, with an uncoated fused silica capillary, 75 microm (i.d.) x 57 cm. PMID:10637048

Liao, T; Wu, J S; Wu, M C; Chang, H M

2000-01-01

364

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

Directory of Open Access Journals (Sweden)

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

Surapaneni Krishna; Venkataramana G

2007-01-01

365

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

International Nuclear Information System (INIS)

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

2006-01-01

366

Anti-obesity effects of chitosan and psyllium husk with L-ascorbic acid in guinea pigs.  

UK PubMed Central (United Kingdom)

The aim of this study was to investigate whether L-Ascorbic acid would facilitate the anti-obesity effects of chitosan and psyllium husk in vivo. The study was carried out with male Hartley guinea pigs for 5 weeks. The results show that chitosan itself did not influence body weight gain and food efficiency ratio (FER). However, the addition of L-Ascorbic acid to chitosan decreased these parameters; the body weight gain and FER in the chitosan-2 group (high-fat diet group with 5 % chitosan containing 0.5 % L-Ascorbic acid) was significantly (p < 0.05) lower than that in F-controls (high-fat diet group), and was similar to that in controls (normal diet group). L-Ascorbic acid enhanced significantly (p < 0.05) the increases of total fecal weight and fecal fat excretion by chitosan. The addition of L-Ascorbic acid to psyllium husk did not differ from psyllium husk alone in terms of changes in weight gain, plasma lipid levels, and fat pad weight. We found that the addition of L-Ascorbic acid to chitosan influenced the reduction in body weight gain and FER, and the increase in total fecal weight and fecal fat excretion in guinea pigs fed a high-fat diet.

Jun SC; Jung EY; Hong YH; Park Y; Kang Dh; Chang UJ; Suh HJ

2012-04-01

367

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

UK PubMed Central (United Kingdom)

The effects of reducing sugars (fructose, glucose, ribose, and arabinose), sucrose, and ascorbic acid were studied on thermo-mechanical properties and crosslinking of egg white proteins (EWP) through Maillard reaction. Sugars (0%, 1%, 5%, and 10%) and ascorbic acid (0%, 0.25%, 0.5%, and 2.5%) were added to EWP solutions. Thermal denaturation and crosslink