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Sample records for ascorbic acid inhibits

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

    OpenAIRE

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

    2004-01-01

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

  2. Ascorbic acid transport into cultured pituitary cells

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-05-01

    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.

  3. Ascorbic Acid Inhibits Replication and Infectivity of Avian RNA Tumor Virus

    Science.gov (United States)

    Bissell, Mina J.; Hatie, Carroll; Farson, Deborah A.; Schwarz, Richard I.; Soo, Whai-Jen

    1980-05-01

    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.

  4. 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)

    Weerayuth SUTTIRAK

    2010-01-01

    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.

  5. Ascorbic acid transport in brain microvascular pericytes.

    Science.gov (United States)

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

    2015-03-01

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

  6. 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

  7. Regeneration of ascorbic acid in human placenta

    International Nuclear Information System (INIS)

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

  8. Regeneration of ascorbic acid in human placenta

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-02-26

    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.

  9. Drug Nanoparticle Formulation Using Ascorbic Acid Derivatives

    OpenAIRE

    Kunikazu Moribe; Waree Limwikrant; Kenjirou Higashi; Keiji Yamamoto

    2011-01-01

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

  10. Ascorbic acid: effects on ricin intoxicated HeLa cells

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

  12. Inhibition of melatonin-induced ascorbic acid and LHRH release by a nitric oxide synthase and cyclic GMP inhibitor.

    Science.gov (United States)

    Karanth, Sharada; Yu, Wen H; Mastronardi, Claudio A; McCann, Samuel M

    2004-07-01

    Melatonin (MEL), the principle secretory product of the pineal gland, has been shown to function as an antioxidant and free-radical scavenger. We previously showed that the release of ascorbic acid (AA) and luteinizing hormone releasing hormone (LHRH) from medial basal hypothalamus (MBH) was mediated by nitric oxide (NO) that released cyclic guanosine 3'5'-mono-phosphate (cGMP). Therefore, it was of interest to evaluate the effect of MEL on AA and LHRH release and study the effect of a nitric oxide synthase (NOS) inhibitor, 6-anilino-5,8-quinoline-dione (LY 83583), and a guanylyl cyclase (GC) inhibitor, 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (O.D.Q.), on the release process. Because NO has been shown to activate soluble guanylyl cyclase that elicited an elevation of cGMP in target cells, in the current investigation LY 83583, O.D.Q., or N(G)-monomethyl-l-arginine (NMMA), a competitive inhibitor of NOS, were used to evaluate their effects on MEL-induced AA and LHRH release. Medial basal hypothalami were incubated in 0.5 ml of Krebs-Ringer bicarbonate (KRB) buffer for 1 hr. Subsequently, the tissues were incubated with graded concentrations of MEL (10(-8) to 10(-4) M), MEL + NMMA (3 x 10(-4) M), MEL + LY 83583 (10(-6) M), or MEL + O.D.Q. (10(-5) M) for 1 hr. Ascorbic acid and LHRH released into the medium were measured by high-performance liquid chromatography (HPLC) and radio-immunoassay (RIA), respectively. Melatonin (10(-6) and 10(-5) M) significantly stimulated both AA and LHRH release, but the lower and the highest concentrations were ineffective. A combination of MEL + NMMA completely blocked both AA and LHRH release, supporting a role for NO in the releasing action. Both LY 83583 and O.D.Q. significantly suppressed MEL-induced AA and LHRH release, emphasizing the role of NOS, GC, and cGMP in mediating the action of MEL. The data of these in vitro experiments support a role for MEL in the hypothalamic control of AA and LHRH release. PMID:15229359

  13. MEAT AND ASCORBIC ACID CAN PROMOTE FE AVAILABILITY FROM FE-PHYTATE BUT NOT FROM FE-TANNIC ACID COMPLEXES

    Science.gov (United States)

    This study utilized an in vitro digestion/Caco-2 cell model to determine the levels of ascorbic acid (AA) and “meat factor” needed to promote Fe absorption from Fe complexed with phytic acid (PA) or tannic acid (TA). Ascorbic acid reversed the inhibition of Fe absorption by phytic acid beginning at...

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

    Science.gov (United States)

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

    1991-10-01

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

  15. 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

  16. Endogenous released ascorbic acid suppresses ethanol-induced hydroxyl radical production in rat striatum.

    Science.gov (United States)

    Huang, Mei; Liu, Wen; Li, Qiang; Wu, Chun Fu

    2002-07-19

    Previous studies have shown that acute systemic administration of ethanol induced ascorbic acid release in the striatum. However, the pharmacological implications of ethanol-induced striatal ascorbic acid release are unclear. In the present study, ethanol-induced extracellular changes of ascorbic acid and hydroxyl radical levels were detected in rat striatum by using brain microdialysis coupled to high-performance liquid chromatography with electrochemical detection. It was found that both in male and female rats, ethanol (3.0 g/kg, i.p.) increased striatal ascorbic acid release in the first 60 min after ethanol administration. Meanwhile, the extracellular hydroxyl radical levels, detected as 2,3- and 2,5-DHBA, were significantly decreased. However, when the ascorbic acid levels returned to the baseline, hydroxyl radical levels rebounded. Administration of DL-fenfluramine (20 mg/kg, i.p.) had no effect on the basal levels of ascorbic acid and hydroxyl radical, but significantly blocked ethanol-induced ascorbic acid release and increased hydroxyl radical levels significantly. Exogenous administration of ascorbic acid (20 mg/kg, s.c.) increased the extracellular levels of ascorbic acid in the striatum, and inhibited the increase of 2,3- and 2,5-DHBA in DL-fenfluramine plus ethanol group. These results provide first evidence that release of endogenous ascorbic acid in the striatum plays an important role in preventing oxidative stress by trapping hydroxyl radical in the central nervous system. PMID:12106669

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

    International Nuclear Information System (INIS)

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

  18. Factitious diabetes mellitus confirmed by ascorbic acid.

    OpenAIRE

    Nading, J. H.; Duval-arnould, B.

    1984-01-01

    We report a girl aged 31/2 years in whom signs and symptoms of diabetes mellitus were falsified by the mother. Evaluation in hospital rapidly ruled out diabetes mellitus and the use of ascorbic acid as a marker enabled us to prove urine substitution by the girl's mother.

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

    Science.gov (United States)

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

    2015-12-01

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

  20. Evaluation of ascorbic acid in protecting labile folic acid derivatives.

    OpenAIRE

    1983-01-01

    The use of ascorbic acid as a reducing agent to protect labile, reduced derivatives of folic acid has been evaluated by high-performance liquid chromatographic separations and Lactobacillus casei microbiological assay of eluate fractions. Upon heating for 10 min at 100 degrees C, solutions of tetrahydropteroylglutamic acid (H4PteGlu) in 2% sodium ascorbate gave rise to 5,10-methylene-H4PteGlu and 5-methyl-H4PteGlu. H2PteGlu acid gave rise to 5-methyl-H4PteGlu and PteGlu. 10-Formyl-H4PteGlu ga...

  1. Ascorbic Acid in the Nutrition of Plant-Feeding Insects.

    Science.gov (United States)

    Vanderzant, E S; Richardson, C D

    1963-05-31

    Bollworms, Heliothis zea (Boddie), and salt-marsh caterpillars, Estigmene acrea (Drury) gradually decreased in ascorbic acid content as they matured, even in its presence. Cotton leafworms, Alabama argillacea (Hübner), also lost ascorbic acid, although a dietary need for the vitamin was not proved. Pink bollworms, Pectinophora gossypiella (Saunders), reared without the vitamin, increased in ascorbic acid content as they matured, an indication that the vitamin was synthesized by the insect. PMID:17836487

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

    DEFF Research Database (Denmark)

    Meyer, Anne S.; Jacobsen, Charlotte

    1996-01-01

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

  3. Simultaneous quantification of capsaicinoids and ascorbic acid from pungent peppers.

    Science.gov (United States)

    Bae, Haejin; Jayaprakasha, Guddadarangavvanahally K; Crosby, Kevin; Jifon, John L; Patil, Bhimanagouda S

    2013-01-01

    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. PMID:23081967

  4. Ascorbic acid enables reversible dopamine receptor 3H-agonist binding

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Zoran Pavlovic

    2004-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Voja Pavlovic

    2004-07-01

    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.

  7. Transport and metabolism of ascorbic acid in human placenta.

    Science.gov (United States)

    Choi, J L; Rose, R C

    1989-07-01

    The role of human placenta in cellular transport and metabolism of the potentially toxic oxidized form and the useful reduced form of ascorbic acid was examined in surviving tissue fragments in vitro. At the end of a 60-min incubation with the 14C label nominally present in the reduced form, a tissue-to-medium ratio in excess of unity was reached. The importance of evaluating uptake of the ascorbic acid metabolites is evident from a careful assay of 14C label present in the bathing media. Significant spontaneous oxidation occurs, which is slowed or reversed to a limited extent by the presence of placental tissue. Uptake of the oxidized substrate, dehydro-L-ascorbic acid, proceeds much more rapidly than uptake of ascorbic acid. At the end of a 15-min incubation, most of the substrate taken up was in the reduced form. From an additional evaluation of 14C label in the bath it is calculated that 25% of ascorbic acid formed by the tissue is released within 15 min. The cellular uptake mechanism for dehydro-L-ascorbic acid is not shared by glucose and is not dependent on the presence of Na+ but is dependent on intact cellular metabolism. The finding of avid cellular uptake and reduction of the oxidized form of ascorbic acid supports the concept that the placenta helps to clear the toxic molecule from the maternal circulation, metabolizes it, and delivers the useful reduced form to the fetus. PMID:2750883

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

    Science.gov (United States)

    Chen, Hongxing; Gu, Zhengbiao

    2014-09-01

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

  9. Synthesis of New L-Ascorbic Ferulic Acid Hybrids

    Directory of Open Access Journals (Sweden)

    Sylvain Rault

    2007-11-01

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

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

    OpenAIRE

    Aniel Kumar, Owk; Subba Tata, Sape

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Devbhuti P*,1

    2011-01-01

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

  12. Radiation protection by ascorbic acid in sodium alginate solutions

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  13. Radiation protection by ascorbic acid in sodium alginate solutions

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

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

    2005-01-01

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

  15. 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

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

    OpenAIRE

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

    2013-01-01

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

  17. [Cystinuria therapy by ascorbic acid (author's transl)].

    Science.gov (United States)

    Asper, R; Schmucki, O

    1982-01-01

    At the beginning of the four chapters on phenomena, analysis, pathophysiology and therapy of cystinuria the essentials of the published literature are summarized. The frequency of cystinuria is in the order of 1:10,000. Besides the cystine lithiasis occurring in nine tenths of all cystinuria patients neurological diseases may also be observed. All commonly applied methods to analyze cystine detect the sum of cystine and cysteine. Cystinuria is characterized by a higher cystine excretion, up to the 100-fold of the normal. Also the concentrations of lysine, arginine and ornithine in the urine of cystinuria patients are elevated, caused by intestinal and renal transport defects. Inevitable damage of renal parenchyma by multiple operations can drastically be reduced by the therapy with D-penicillamine or alpha-mercaptopropionylglycine. The disadvantages of that formation of soluble asymmetric disulfides are the side effects, such as nausea, gastric difficulties and dermatosis, occurring in up to 50% of the patients. Using the especially developed method with HPLC separation and electrochemical detector with a mercury electrode, cystine and cysteine are analyzed simultaneously. In the urine of healthy persons the molar concentration of cysteine is in the same order as cystine. But in cystinuria the cysteine concentration in urine is about a thousand times less than that of cystine. These results are evidence that a shifted redox-equilibrium of cystine-cysteine is also typical of cystinuria. The molar cysteine percentage of cysteine in healthy persons is increased from 30 to 50% by oral ascorbic acid administration. Therefore a vitamin C therapy for cystinuria is developed. 31 cystinuria patients who receive 5 g of vitamin C a day show a decrease in the cystine concentration of about 40%. Up to now, no side effects have been observed. The most obvious sign of the positive effect of the proposed vitamin C therapy for cystinuria is the missing cystine sediment in fresh urine. PMID:7112765

  18. Possible role of ascorbic acid in the oxidative damage induced by inhaled crystalline silica particles

    OpenAIRE

    COLUCCIA, Salvatore; Fenoglio, Ivana; Fubini, Bice; MARTRA, Gianmario

    2000-01-01

    The selective interaction of ascorbic acid with crystalline silica (quartz) has been studied by measuring the ascorbic acid consumption (by means of UV/vis and IR spectroscopy) and the release of silicon when quartz particles or amorphous silica (Aerosil 50) is incubated in ascorbic acid solution. At a physiological ascorbic acid concentration, quartz, and not amorphous silica, reacts, suggesting the formation of a 1:1 silicon-ascorbate complex, while at higher concentrations, the reacting am...

  19. ESR Study on Irradiated Ascorbic Acid Single Crystal

    Science.gov (United States)

    Tuner, H.; Korkmaz, M.

    2007-04-01

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

  20. Phytic Acid Inhibits Lipid Peroxidation In Vitro

    OpenAIRE

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

    2013-01-01

    Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100??M and 500??M effectively inhibited the deca...

  1. ESR Study on Irradiated Ascorbic Acid Single Crystal

    International Nuclear Information System (INIS)

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

  2. Enzymatic methods in food analysis: determination of ascorbic acid.

    Science.gov (United States)

    Shekhovtsova, Tatyana N; Muginova, Svetlana V; Luchinina, Julia A; Galimova, Anna Z

    2006-07-28

    The feasibility and expediency of enzymatic methods application in food analysis is demonstrated by the example of ascorbic acid (AsA) determination in foods. Enzymatic determination of ascorbic acid is based on its action as a second substrate of horseradish (HRP) and peanut (PNP) peroxidases in the reactions of o-dianisidine (OD) and 3,3',5,5'-tetramethylbenzidine (TMB) oxidation with hydrogen peroxide. The rates of the reactions are monitored spectrophotometrically by measuring the duration of the induction period on kinetic curves plotted in coordinates absorption-time. The proposed procedures are sensitive (c(L)=0.1 microM), simple, and rapid. The procedure using horseradish peroxidase and the reaction of TMB oxidation was used to determine ascorbic acid in fruit juices, milk and sour-milk products for babies' nutrition. PMID:17723515

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Prashansa Sharma

    2014-09-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  7. Performance of structured lipids incorporating selected phenolic and ascorbic acids.

    Science.gov (United States)

    Gruczynska, Eliza; Przybylski, Roman; Aladedunye, Felix

    2015-04-15

    Conditions applied during frying require antioxidant which is stable at these conditions and provides protection for frying oil and fried food. Novel structured lipids containing nutraceuticals and antioxidants were formed by enzymatic transesterification, exploring canola oil and naturally occurring antioxidants such as ascorbic and selected phenolic acids as substrates. Lipozyme RM IM lipase from Rhizomucor miehei was used as biocatalyst. Frying performance and oxidative stability of the final transesterification products were evaluated. The novel lipids showed significantly improved frying performance compared to canola oil. Oxidative stability assessment of the structured lipids showed significant improvement in resistance to oxidative deterioration compared to original canola oil. Interestingly, the presence of ascorbic acid in an acylglycerol structure protected ?-tocopherol against thermal degradation, which was not observed for the phenolic acids. Developed structured lipids containing nutraceuticals and antioxidants may directly affect nutritional properties of lipids also offering nutraceutical ingredients for food formulation. PMID:25466089

  8. Comparative study of the quercetin, ascorbic acid, glutathione and superoxide dismutase for nitric oxide protecting effects in mouse gastric fundus.

    Science.gov (United States)

    Ertu?, Peyman U; Aydinoglu, Fatma; Goruroglu Ozturk, Ozlem; Singirik, Ergin; Ögülener, Nuran

    2013-01-01

    The aim of this work was to compare the preventing capacity of quercetin with Cu/Zn superoxide dismutase (Cu/Zn SOD), ascorbic acid and glutathione on nitric oxide (NO)-induced relaxation in mouse gastric fundus. Furthermore, the effects of the quercetin on the tissue level of total oxidant and antioxidant was investigated. Nitrergic stimulation (4Hz, 25V, 0.1 ms, 10s-train) and exogenous NO (10 ?M) induced relaxation. Pyrogallol (10 ?M), hydroquinone (100 ?M) and LY83583 (6-Anilino-quinolin-5,8-quinone, 5 ?M) inhibited nitrergic relaxations. The inhibition observed with pyrogallol, hydroquinone and LY83583 was prevented by quercetin (0.1 ?M). Also, ascorbic acid (500 ?M), glutathione (100 ?M) and Cu/Zn SOD (100 U/ml) prevented the inhibitory effect of superoxide anion generators on the relaxation to nitrergic stimulation and NO. Diethyldithiocarbamic acid (DETCA; 8mM) inhibited nitrergic relaxations. DETCA-induced inhibition on nitrergic stimulation and NO-induced relaxation was prevented by quercetin, ascorbic acid, glutathione or Cu/Zn SOD. DETCA plus pyrogallol, hydroquinone or LY83583 strengthened the inhibition on the relaxations. Also, pre-treatment with quercetin, ascorbic acid and glutathione prevented the inhibitory effect of DETCA plus LY-83583 on the relaxation to nitrergic stimulation and NO but Cu/Zn SOD did not prevent this inhibition. Also, quercetin increased tissue total antioxidant capacity and decreased tissue oxidant level and oxidative stress index in DETCA-treatment group. These results indicate that quercetin has antioxidant effect and protects NO from endogenous superoxide anion-driven inactivation and enhances its biological activity, suggesting that quercetin may scavenge superoxide anion in a Cu/Zn SOD, glutathione or ascorbic acid-inhibitable manner. PMID:23085029

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

    Directory of Open Access Journals (Sweden)

    R. Mirshekar

    2009-01-01

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

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

    OpenAIRE

    May, James M.; Qu, Zhi-chao

    2010-01-01

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

  11. Spectroscopic investigation of the interaction between ?-cyclodextrin and ascorbic acid

    International Nuclear Information System (INIS)

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

  12. Study of Polymorph Prediction For L-Ascorbic Acid

    OpenAIRE

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

    2005-01-01

    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 n...

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

    DEFF Research Database (Denmark)

    Zhou, A; Matsumoto, T

    1990-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

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

    Science.gov (United States)

    Pappenberger, Günter; Hohmann, Hans-Peter

    2014-01-01

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

  16. Ascorbic acid offsets the inhibitory effect of bioactive dietary polyphenolic compounds on transepithelial iron transport in Caco-2 intestinal cells.

    Science.gov (United States)

    Kim, Eun-Young; Ham, Soo-Kyung; Bradke, Daniel; Ma, Qianyi; Han, Okhee

    2011-05-01

    We previously reported that (-)-epigallocatechin-3-gallate (EGCG) and grape seed extract (GSE) at high concentration nearly blocked intestinal iron transport across the enterocyte. In this study, we aimed to determine whether small amounts of EGCG, GSE, and green tea extract (GT) are capable of inhibiting iron absorption, to examine if ascorbic acid counteracts the inhibitory action of polyphenols on iron absorption, and to explore the mechanisms of polyphenol-mediated apical iron uptake and basolateral iron release. An(55)Fe absorption study was conducted by adding various concentrations of EGCG, GSE, and GT using Caco-2 intestinal cells. Polyphenols were found to inhibit the transepithelial (55)Fe transport in a dose-dependent manner. The addition of ascorbic acid offset the inhibitory effects of polyphenols on iron transport. Ascorbic acid modulated the transepithelial iron transport without changing the apical iron uptake and the expression of ferroportin-1 protein in the presence of EGCG. The polyphenol-mediated apical iron uptake was inhibited by membrane impermeable Fe(2+) chelators (P ferrous ions and possibly by increasing the uptake of polyphenol-iron complexes via the energy-independent pathway. The present results indicate that the inhibitory effects of dietary polyphenols on iron absorption can be offset by ascorbic acid. Further studies are needed to confirm the current findings in vivo. PMID:21430251

  17. The effect of supplemental ascorbic acid on serum vitamin B12 levels in myelomeningocele patients.

    Science.gov (United States)

    Ekvall, S; Chen, I W; Bozian, R

    1981-07-01

    Serum levels of ascorbic acid and vitamin B12 were analyzed in 40 myelomeningocele children to study the effect of supplemental ascorbic acid on serum vitamin B12 levels. The experimental group was composed of 20 children receiving ascorbic acid for urinary acidification: 10 received an average of 1.8 g daily, 10 received an average of 1.5 g daily (the amount depending on the requirement needs for urinary acidification) half of each group received ascorbic acid for less than 3 yr (an average of 2.1 yr) and half received ascorbic acid for more than 3 yr (an average of 4.3 yr). The control group consisted of 20 myelomeningocele children not receiving supplemental ascorbic acid. Both groups were matched for age, sex, race, and physical activity. Dietary levels of ascorbic acid and B12 were calculated to rule out their influence on serum levels. Results showed that the experimental group with supplemental ascorbic acid produced significantly higher ascorbic acid values than the control group. The serum B12 levels of the experimental group were not significantly different than those of the control groups and these children showed neither a deficient serum levels of B12, anemia, nor elevated mean corpuscular volume. Hemoglobin levels were slightly higher for the experimental group. Dietary calculations of B12 and ascorbic acid were not significantly greater than the Recommended Daily Allowance ruling out any influence of diet on serum levels. No evidence of vitamin B12 deficiency developed in 20 myelomeningocele children receiving daily mean doses of 1.65 g of supplemental ascorbic acid. In view of our findings, it is highly improbable that megadoses of supplemental ascorbic acid would induce vitamin B12 deficiency in man. PMID:7258126

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

    Science.gov (United States)

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

    2015-04-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  2. Improvement of bioavailability for iron from vegetarian meals by ascorbic acid

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2004-01-01

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

  4. Retention of ascorbic acid in fortified orange juice powers during storage

    Directory of Open Access Journals (Sweden)

    G. S. Siddappa

    1960-10-01

    Full Text Available Both Coorg and Sathgudi orange juice powders are good carriers for added ascorbic acid during prolonged storage at ordinary temperatures. There is not much difference between nitrogen and air packs as regards retention of ascorbic acid during storage. Nitrogen pack, however, helps to keep the power in a better free-flowing condition.

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

    International Nuclear Information System (INIS)

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

  6. Long-term observation of young cystinuric patients under ascorbic acid therapy.

    Science.gov (United States)

    Lux, B; May, P

    1983-01-01

    Long-term results of ascorbic acid monotherapy in four young patients with cystine stone complaints are reported. The therapeutic program is based on the descriptions by Asper and Schmucki, who publicized the method for the first time in 1979. Clinical course observations, renal function checks as well as the excretion of cystine, uric acid and oxalic acid during ascorbic acid therapy of our patient pool will be discussed. Clinical observations made to date indicate that ascorbic acid therapy is a practical, inexpensive prophylaxis for cystine stone patients that is virtually free of side effects. PMID:6845567

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

    Directory of Open Access Journals (Sweden)

    Bisht Surendra S

    2006-12-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Ion Bara

    2006-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Dickton Darby

    2008-08-01

    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.

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

    Science.gov (United States)

    Goto, Hideaki; Fukushi, Yudai; Nishioka, Yasushiro

    2014-11-01

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

  11. Study of Polymorph Prediction For L-Ascorbic Acid

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    Dilhan M. Kalyon

    2005-12-01

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

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

    Scientific Electronic Library Online (English)

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

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

  13. Reductive dechlorination of carbon tetrachloride using buffered alkaline ascorbic acid.

    Science.gov (United States)

    Lin, Ya-Ting; Liang, Chenju

    2015-10-01

    Alkaline ascorbic acid (AA) was recently discovered as a novel in-situ chemical reduction (ISCR) reagent for remediating chlorinated solvents in the subsurface. For this ISCR process, the maintenance of an alkaline pH is essential. This study investigated the possibility of the reduction of carbon tetrachloride (CT) using alkaline AA solution buffered by phosphate and by NaOH. The results indicated that CT was reduced by AA, and chloroform (CF) was a major byproduct at a phosphate buffered pH of 12. However, CT was completely reduced by AA in 2M NaOH without CF formation. In the presence of iron/soil minerals, iron could be reduced by AA and Fe(2+) tends to precipitate on the mineral surface to accelerate CT degradation. A simultaneous transfer of hydrogenolysis and dichloroelimination would occur under phosphate buffered pH 12. This implies that a high alkaline environment is a crucial factor for maintaining the dominant pathway of two electron transfer from dianionic AA to dehydroascorbic acid, and to undergo dichloroelimination of CT. Moreover, threonic acid and oxalic acid were identified to be the major AA decomposition products in alkaline solutions. PMID:25912910

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Ali Akbar Aliabadi

    2006-04-01

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

  16. Ascorbic Acid Mediated Iron Toxicity in Caco-2 Cells:Effects of Different Iron Species

    OpenAIRE

    Ekmekcioglu, Cem; Zodl, Bettina; Humpeler, Susanne; Zeiner, Michaela; Gundacker, Claudia; Steffan, Ilse

    2013-01-01

    Aim of the presented study was to investigate whether scorbic acid enhances iron uptake and/or toxicity in Caco-2 cells. Cells were incubated with 1.5 mM of different iron species combined with increasing doses of ascorbic acid (1-3 mM). Thereafter viability, membrane damage, lipid peroxidation, and intracellular iron concentrations were measured. No effects on iron-induced damage to cells were found regarding viability. Lipid peroxidation significantly increased when ascorbic acid was ad...

  17. Use of an electrochemically etched platinum microelectrode for ascorbic acid mapping in oranges.

    Science.gov (United States)

    Paixão, Thiago R L C; Lowinsohn, Denise; Bertotti, Mauro

    2006-04-19

    A positionable platinum microelectrode fabricated by electrochemical etching was used to monitor the concentration of ascorbic acid in fruits and vegetables. Studies carried out with ascorbate oxidase confirmed the suitability of the amperometric sensor to measure selectively the ascorbic acid content. The results obtained with the proposed method for ascorbic acid determination in orange juices compared well with those found by iodimetry with coulometrically generated iodine. The standard deviation calculated by measuring limiting current values in voltammograms was found to be 3% (n = 150). The sensor allowed the evaluation of the spatial distribution of ascorbic acid concentration in oranges by in-situ measurements. Ascorbic acid concentration maps show that in a perpendicular cut the concentration is higher near the peel to the center of the fruit. In a parallel cut, the concentration increases with the distance to the stem. A correlation between the ripening stage and the ascorbic acid concentration was also observed from electrochemical measurements, the content being higher in mature fruits. PMID:16608233

  18. Effect of dietary ascorbic acid on the incidence of spontaneous mammary tumors in RIII mice.

    OpenAIRE

    Pauling, L; Nixon, J. C.; Stitt, F; Marcuson, R; Dunham, W B; R. Barth; Bensch, K; Herman, Z S; Blaisdell, B E; Tsao, C

    1985-01-01

    A study of the effect of different amounts of L-ascorbic acid (vitamin C), between 0.076% and 8.3%, contained in the food has been carried out with ten groups of RIII mice (seven ascorbic acid and three control groups), with 50 mice in each group. With an increase in the amount of ascorbic acid there is a highly significant decrease in the first-order rate constant for appearance of the first spontaneous mammary tumor after the lag time to detection by palpation. There is also an increase in ...

  19. Suspected ascorbic acid deficiency in a colony of squirrel monkeys (Saimiri sciureus).

    Science.gov (United States)

    Demaray, S Y; Altman, N H; Ferrell, T L

    1978-08-01

    Subperiosteal cranial hematomas were observed in five female squirrel monkeys. The absence of trauma in the clinical history, the characteristic clinical changes, and the pathological lesions suggested that the animals were scorbutic. Analysis of feed which was soaked in water, or left on the ground for varying time periods at different temperatures, indicated that there was loss of ascorbic acid. During the manufacture of monkey feed, ascorbic acid is dusted on as a final process. The practice of soaking feed resulted in the "washing off" or the destruction of ascorbic acid. This disease outbreak emphasized the important of management practices in a primate colony. PMID:100654

  20. A study of the interaction of europium, samarium, and platinum(II) with ascorbic acid and 1,10-phenanthroline

    International Nuclear Information System (INIS)

    By the methods pf pH-potentiometry, photocolorimetry and electron spectroscopy europium(III), samarium(III) and platinum(II) interaction with ascorbic acid and 1,10-phenanthroline is studied. Stability of acid and neutral ascorbate samarium complexes is determined. Heteroligand ascorbate-phenanthrolinate samarium(III) and platinum(II) complexes are separated from aqua-ethanol solution

  1. Novel Postharvest Treatment Reduces Ascorbic Acid Losses in Mango (Mangifera indica L. Var. Kent

    Directory of Open Access Journals (Sweden)

    Maria A. Islas-Osuna

    2010-01-01

    Full Text Available Problem statement: Mango is a tropical fruit that ripens very quickly; for this reason, there has been a continuous effort to develop postharvest technologies to extend its shelf life and quality. Among them, 1-Methylcyclopropene (1-MCP is widely used because it inhibits the action of ethylene receptors. Approach: Changes in physicochemical parameters, bioactive compounds and cell wall degrading activities were evaluated during storage and ripening of fresh whole mangoes treated with 1-MCP (750 nL L-1. Mature-green mangoes, cultivar Kent, untreated or treated with 1-MCP were evaluated for external quality, phytochemicals, Polygalacturonase (PG and Pectin Methylesterase (PME enzymatic activities during storage at 20°C for 2 weeks. Results: Concentration of ascorbic acid decreased during fruit ripening but 1-MCP-treated mangoes had reduced losses. Polygalacturonase and pectin methylesterase activities were reduced in the treated fruits as compared to untreated mangoes. Small changes in ?-carotene were observed between treated and untreated fruits. Conclusion: 1-MCP affected the ripening process in Kent mango, reducing losses of ascorbic acid, this treatment is justified since it helps to maintain mangos nutritional value during its shelf life.

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

    Science.gov (United States)

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

    2001-08-01

    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

  3. Radiolytical oxidation of ascorbic acid in aqueous solutions

    International Nuclear Information System (INIS)

    Complete text of publication follows. Ascorbic acid, AsA (vitamin c), has been widely studied as an antioxidant or as an initiator of some technological processes, for example polymerization or nanoparticles formation. AsA can be easily oxidized to ascorbyl radical, in the first stage, and to dehydroascorbic acid, DHA, in the second stage. It has been found that several different ascorbyl radicals are formed during AsA oxidation but the main radical exists as the anion with the unpaired electron delocalized on a highly conjugated tricarbonyl system. Absorption spectrum of ascorbyl radical shows two bands with maxima at 300 and 360 nm, however only that at 360 nm is proportional to the dose and thus this wavelength was chosen for observations. We studied the oxidation of AsA by the following oxidizing radicals generated by the pulse radiolysis method ·OH, (SCN)2-·, Cl2-·, N3· and NO2·. The observed dependence of the yield and the formation rate of the AsA radical on the reduction potential of the oxidizing radical is discussed. The results obtained in water are compared with those obtained with AsA enclosed in the water pools of reverse micelles formed by AOT in n-heptane or by Igepal CO-520 in c-hexane. Somewhat surprising observation of different ascorbyl radical in pulse irradiated reverse micelles containing DHA is also commented.ted.

  4. 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)

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

    Czech Academy of Sciences Publication Activity Database

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

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Antonio De Michelis

    2007-01-01

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

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

    Czech Academy of Sciences Publication Activity Database

    Šrogl, Ji?í; Voltrová, Svatava

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Antesar Elmagirbi

    2012-10-01

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

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

    International Nuclear Information System (INIS)

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

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

    Scientific Electronic Library Online (English)

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

    2014-09-01

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

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

    Science.gov (United States)

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

    1999-10-01

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

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

    OpenAIRE

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

    2011-01-01

    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), aged from 20 to 84 years (median age 59.5 years), who attended our Department, were divided into two groups, age and sex matched, and underwent colonoscopy. Two questionnaires, one for patients repo...

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

    OpenAIRE

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

    2009-01-01

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

  14. Role of ascorbic acid against pathogenesis in plants

    Directory of Open Access Journals (Sweden)

    Taqi Ahmed Khan

    2011-09-01

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

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

    Science.gov (United States)

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

    2015-04-15

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

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

    OpenAIRE

    Gamze Erdo?du; Mehmet Mutluhan Mutlu

    2011-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-05-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Juven, B J; Kanner, J

    1986-10-01

    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. PMID:3781941

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

    Scientific Electronic Library Online (English)

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

    2008-12-01

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

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

    OpenAIRE

    Zhousheng Yang; Yanling Wang; Guiying Jin; Yuzhong Zhang

    2003-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Nada, H.A. Al- Twaty

    2005-03-01

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

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

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Timm Heinrich, Maike

    2001-01-01

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

  7. Increasing neurogenesis with fluoxetine, simvastatin and ascorbic Acid leads to functional recovery in ischemic stroke.

    Science.gov (United States)

    Corbett, Adrian M; Sieber, Scott; Wyatt, Nicholas; Lizzi, Jenna; Flannery, Tiffany; Sibbit, Bethany; Sanghvi, Saagar

    2015-01-01

    Less than 8.5% of ischemic stroke patients receive clot-busting drugs within the narrow time needed to reduce injury. Thus, there is need for an easily-accessible delayed post-stroke drug treatment to improve functional recovery. Various combinations of fluoxetine, simvastatin, and ascorbic acid were given to healthy rats to assess impact on neurogenesis versus controls. Fluoxetine combined with simvastatin and ascorbic acid produced a 19-fold increase in neurogenesis versus controls in healthy rats; fluoxetine alone produced 10-fold increase. We next tried a couple of drug combinations versus control in endothelin-induced stroked rats. Combined fluoxetine/ simvastatin/ascorbic acid treatment, given to stroked rats 20-26 hours after stroke induction and continued for 31 days, produced strong recovery as measured by Montoya staircase test (mean recovery to 85% of pre-stroke function) and Forelimb Asymmetry test (mean recovery to 90% of pre-stroke function). Fluoxetine and ascorbic acid without simvastatin only produced ~50% of recovery produced by the 3-drug combination. Our results indicate that combined treatment of Fluoxetine, simvastatin and ascorbic acid represents a promising delayed stroke treatment that greatly improves functional recovery in rats and warrants further study in human patient populations. This work formed the basis for a patent submission (US20130065924A1) Composition and method for treatment of neurodegeneration. PMID:25612744

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

    International Nuclear Information System (INIS)

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

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

    Scientific Electronic Library Online (English)

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

    1211-12-01

    Full Text Available 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.

  10. Carbon nanoparticles with tosyl functional group for distinguishing voltammetric peaks of ascorbic acid and uric acid.

    Science.gov (United States)

    Amiri, Mandana; Imanzadeh, Hamideh; Banaei, Alireza

    2015-02-01

    In this approach, electro-oxidation of a mixture of uric acid and ascorbic acid at the surface of tosyl surface carbon nanoparticles/glassy carbon electrode has been performed. The electro-oxidation of these compounds at bare electrode is sluggish and there is no suitable peak separation between them. However, using functionalized carbon nanoparticles, two well-defined anodic peaks with a considerable enhancement in the peak current and a remarkable peak potential separation near 452 mV is obtained. The porous interfacial layer of the carbon nanoparticles modified electrode with a high specific surface area increases the conductive area; molecules can penetrate through the conductive porous channels onto the electrode more easily so leading to higher sensitivity and selectivity. The dynamic linear ranges of 1.0 × 10(-5) to 3.0 × 10(-3)M and 1.0 × 10(-7) to 1.0 × 10(-4)M with detection limits 1.0 × 10(-5)M and 2.0 × 10(-8)M (for S/N=3) were obtained for ascorbic acid and uric acid, respectively. Analytical utility of the modified electrode has been examined successfully using human urine samples and vitamin C commercial tablets. PMID:25492188

  11. Modulation of ascorbic acid metabolism by cytochrome P450 induction revealed by metabonomics and transcriptional profiling.

    Science.gov (United States)

    Aranibar, Nelly; Bhaskaran, Vasanthi; Ott, Karl-Heinz; Vassallo, Jeff; Nelson, David; Lecureux, Lloyd; Gong, Lei; Stryker, Steve; Lehman-McKeeman, Lois

    2009-12-01

    In the present study, NMR-based urinary metabonomic profiles resulting from dosing with widely recognized microsomal enzyme inducers were evaluated in male rats. Wistar or Sprague-Dawley rats were dosed daily by oral gavage with phenobarbital (PB; 100 mg/kg), diallyl sulfide (DAS; 500 mg/kg), the investigational compound DMP-904 (150 mg/kg), or beta-naphthoflavone (BNF; 100 mg/kg) for 4 days, and urine was collected daily for analysis. Compounds known to increase cytochrome P450 2B enzymes, including PB, DAS and DMP-904, increased the urinary excretion of gulonic and ascorbic acid in a time-dependent manner, reaching a maximum following 3-4 days of dosing. In contrast, BNF, an agent that induces primarily Cyp1A enzymes, did not increase gulonic or ascorbic acid excretion, despite inducing Cyp1A1 more than 200-fold. Given the metabonomic results, hepatic transcriptional changes in the regulation of ascorbic acid biosynthesis were determined by RT-PCR. All Cyp2B inducers increased hepatic mRNA levels of aldo-keto reductase 1A1, an enzyme that catalyzes the formation of gulonic acid from glucuronate with concurrent decreased expression of both regucalcin (Rgn), the enzyme responsible for conversion of gulonic acid to gulono-1, 4-lactone and gulonolactone oxidase (Gulo), the rate-limiting enzyme in ascorbate biosynthesis. These effects would be expected to increase levels of gulonic acid. In addition, Cyp2B inducers also increased hepatic expression of enzymes regulating ascorbic acid reutilization including glutaredoxin reductase (Glrx2) and thioredoxin reductase (Txnrd1). In contrast, BNF did not effect hepatic expression of any enzyme regulating gulonic or ascorbic acid biosynthesis. Thus, some microsomal enzyme inducers alter transcriptional regulation of ascorbic acid biosynthesis, and these changes are detected by noninvasive metabonomic profiling. However, not all microsomal enzyme inducers appear to alter ascorbic acid metabolism. Finally, the work illustrates how metabonomic results can direct additional studies to determine the biochemical mechanisms underlying changes in urinary metabolite excretion. PMID:19768707

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

    Directory of Open Access Journals (Sweden)

    R. Suresh

    2010-01-01

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

  13. Simultaneous determination of iron (II) and ascorbic acid in pharmaceuticas based on flow sandwich technique.

    Science.gov (United States)

    Vakh, Christina; Freze, Elena; Pochivalov, Alexsey; Evdokimova, Ekaterina; Kamencev, Mihail; Moskvin, Leonid; Bulatov, Andrey

    2015-01-01

    The simple and easy performed flow system based on sandwich technique has been developed for the simultaneous separate determination of iron (II) and ascorbic acid in pharmaceuticals. The implementation of sandwich technique assumed the injection of sample solution between two selective reagents and allowed the carrying out in reaction coil two chemical reactions simultaneously: iron (II) with 1,10-phenanthroline and ascorbic acid with sodium 2,6-dichlorophenolindophenol. For achieving of excellent repeatability and considerable reagent saving the various parameters such as flow rate, sample and reagent volumes, reaction coil length were also optimized. The limits of detection (LODs) obtained by using the developed flow sandwich-type approach were 0.2mgL(-1) for iron (II) and 0.7mgL(-1) for ascorbic acid. The suggested approach was validated according to the following parameters: linearity and sensitivity, precision, recoveries and accuracy. The sampling frequency was 41h(-1). PMID:25862995

  14. Thermodynamic and Ultrasonic Properties of Ascorbic Acid in Aqueous Protic Ionic Liquid Solutions

    Science.gov (United States)

    Singh, Vickramjeet; Sharma, Gyanendra; Gardas, Ramesh L.

    2015-01-01

    In this work, we report the thermodynamic and ultrasonic properties of ascorbic acid (vitamin C) in water and in presence of newly synthesized ammonium based protic ionic liquid (diethylethanolammonium propionate) as a function of concentration and temperature. Apparent molar volume and apparent molar isentropic compression, which characterize the solvation state of ascorbic acid (AA) in presence of protic ionic liquid (PIL) has been determined from precise density and speed of sound measurements at temperatures (293.15 to 328.15) K with 5 K interval. The strength of molecular interactions prevailing in ternary solutions has been discussed on the basis of infinite dilution partial molar volume and partial molar isentropic compression, corresponding volume of transfer and interaction coefficients. Result has been discussed in terms of solute-solute and solute-solvent interactions occurring between ascorbic acid and PIL in ternary solutions (AA + water + PIL). PMID:26009887

  15. The analysis of black powder substitutes containing ascorbic acid by ion chromatography/mass spectrometry.

    Science.gov (United States)

    Lang, Gui-hua Lisa; Boyle, Katherine M

    2009-11-01

    Black powder substitutes containing ascorbic acid are a group of low explosives that utilize ascorbic acid as the fuel. The analysis of these powders is complicated by the degradation of ascorbic acid which occurs rapidly in solution and may also occur as the powder ages. Aqueous extracts of both intact powders and postblast residues were analyzed by an existing ion chromatography/mass spectrometry (IC/MS) method used at the Bureau of Alcohol, Tobacco, Firearms and Explosives. Results have shown that while ascorbic acid itself is not detected in this method, its diagnostic degradation products (threonic acid, monohydrated diketogulonic acid, and oxalic acid) can be identified. In addition, anions from the inorganic oxidizers (perchlorate and nitrate) and combustion products such as chloride, chlorate, and nitrite, can be identified within the same experiment. While this IC/MS method shows promise, future modifications are necessary because of limitations in identifying threonate in postblast residues, as well as coeluting compounds observed in postblast residues. PMID:19732276

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

    Science.gov (United States)

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

    2013-05-01

    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

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

    Directory of Open Access Journals (Sweden)

    M. Shahedi

    2001-10-01

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

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

    2008-01-01

    Abstract Background The expression of human milk for later use is on the rise. Bottle systems are used to deliver the expressed milk. Research has shown that storage of both human milk and artificial baby milk, or infant formula, leads to a loss of ascorbic acid (commonly called Vitamin C). As milk is removed from the bottle during feeding and replaced by ambient air, it is unknown if loss of ascorbic acid occurs during the course of a feeding. The purpose of this study is to investigate the ...

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

    International Nuclear Information System (INIS)

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

  1. Determination of ascorbic acid and carotenoids in food commodities by liquid chromatography with mass spectrometry detection.

    Science.gov (United States)

    Frenich, A Garrido; Torres, M E Hernández; Vega, A Belmonte; Vidal, J L Martínez; Bolaños, P Plaza

    2005-09-21

    Two methods, one to determine ascorbic acid and one to determine lycopene and beta-carotene, in vegetables and fruits by liquid chromatography coupled with mass spectrometry (LC-MS) have been established. The chromatographic separation of the studied compounds and their MS parameters were optimized to improve selectivity and sensitivity. In both methods, separation was carried out with two coupled columns, first a C(18) and then a dC(18), using as mobile phase 70% methanol (0.005% acetic acid) and 30% acetic acid 0.05% for ascorbic acid determination and a mixture of methanol, tetrahydrofuran, and acetonitrile (60:30:10 v/v/v) for carotenoid analysis in isocratic mode. The molecular ion was selected for the quantification in selective ion monitoring (SIM) mode. Ascorbic acid was detected with electrospray ionization probe (ESI) in negative mode, while chemical ionization atmospheric pressure (APCI) in positive mode was used for the target carotenoids. The methodology for ascorbic acid analysis is based on an extraction with polytron using methanol and a mixture of methaphosphoric acid and acetic acid. Extraction of the carotenoids was carried out with tetrahydrofuran/methanol (1:1) (v/v). The proposed methods were applied, after their corresponding validations, to the analysis of four varieties of tomatoes, tomato in tin enriched and dried tomato, and to the analysis of mango and kiwi fruits, to compare the content in these compounds. Moreover, the influence of the process of freezing and the effect that the manipulation/preservation has in the content of ascorbic acid in tomato have also been studied. PMID:16159160

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-05-01

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

  3. 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

  4. A colorimetric probe for ascorbic acid based on copper-gold nanoparticles in electrospun nylon

    International Nuclear Information System (INIS)

    We report on a colorimetric probe based on copper-gold alloy nanoparticles (NPs). The probe is capable of selectively detecting ascorbic acid (AA) as a result of the distance-dependent colour change of the nanoparticles immobilized in an electrospun nylon-6 nanofiber. The resulting white nanofibres undergo a colour change to blue as a result of the aggregation of the NPs induced by AA in the pH range 2–7. The probe is selective for AA even in the presence of dopamine, uric acid, saccharides, amino acids and certain organic acids. It covers the 1.76 x10?2 mg L?1 to 1.76 x105 mg L?1 concentration range, and exhibits a limit of detection of 1.76 x10?2 mg L?1 based on visual detection. Its application was demonstrated by the determination of ascorbic acid in fruit juices, urine, serum, and vitamin C tablets. (author)

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

    Science.gov (United States)

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

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

    Directory of Open Access Journals (Sweden)

    Samina Malik and Muhammad Ashraf

    2012-05-01

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

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

    Science.gov (United States)

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

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

    Directory of Open Access Journals (Sweden)

    Samuel Tilahun

    2013-10-01

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

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

    Science.gov (United States)

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

    2014-10-01

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

  10. 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

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

    Directory of Open Access Journals (Sweden)

    Samuel Tilahun

    2013-08-01

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

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

    Science.gov (United States)

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

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

    Czech Academy of Sciences Publication Activity Database

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

    2003-01-01

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

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

    Czech Academy of Sciences Publication Activity Database

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

    2002-01-01

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

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

    OpenAIRE

    Bowman, Gene L.

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Jokanovi? Marija R.

    2009-01-01

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

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

    OpenAIRE

    Bisht Surendra S; Singh Biswajit K; Tripathi Rama P

    2006-01-01

    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 ...

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

    Directory of Open Access Journals (Sweden)

    Al-Rejaie Salim

    2012-03-01

    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.

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

    International Nuclear Information System (INIS)

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

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

    Scientific Electronic Library Online (English)

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

    2011-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Andrea M. Wynne

    2015-04-01

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

  3. Ascorbic acid in diet supplements: loss in the manufacturing process and storage.

    Science.gov (United States)

    Giménez, R; Cabrera, C; Olalla, M; Ruiz, M D; López, M C

    2002-11-01

    The ascorbic acid content was determined in 25 different diet supplements commercially available to the consumer in two pharmaceutical forms (pills and ampoules). These products are widely consumed by several population groups (elderly people, sportsmen, adolescents, children, etc.). High-performance liquid chromatography was used as the analytical technique. The proposed method has been validated with good linearity, reproducibility, recovery and accuracy, and can be used in routine analyses and in quality control. The ascorbic acid content in pills ranged from 15.62 to 50.16 mg/g, and in that ampoules from 2.12 to 8.83 mg/ml. Depending on the dosage rates, these levels would represent approximately 20-50% of the daily dietary intake recommended by the National Research Council. Possible losses in the manufacturing process and stability during storage for 30 days at 40 +/- 2 degrees C without light, were tested. In relation to the ascorbic acid concentrations stated on the labels, a loss of 12.0-21.9% in pills and of 11.7-18.0% in ampoules was detected. In relation to the stability conditions, the losses are of 1.8-24.8% in pills and of 10.4-19.3% in ampoules. The pasteurisation and sterilisation processes produced a mean loss of ascorbic acid in ampoules of 2.1 and 1.4%, respectively. A statistically significant direct correlation was observed between ascorbic acid loss and content in proteins, humidity, ash, and fructose. The influence of the pharmaceutical form was also tested. Data revealed that the control of losses during the manufacturing and commercialisation process of these products is necessary to ensure the intake of vitamin C from these products by the consumer. PMID:12590746

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  6. Ascorbic Acid Offsets the Inhibitory Effect of Bioactive Dietary Polyphenolic Compounds on Transepithelial Iron Transport in Caco-2 Intestinal Cells12

    OpenAIRE

    Kim, Eun-young; Ham, Soo-kyung; Bradke, Daniel; Ma, Qianyi; Han, Okhee

    2011-01-01

    We previously reported that (-)-epigallocatechin-3-gallate (EGCG) and grape seed extract (GSE) at high concentration nearly blocked intestinal iron transport across the enterocyte. In this study, we aimed to determine whether small amounts of EGCG, GSE, and green tea extract (GT) are capable of inhibiting iron absorption, to examine if ascorbic acid counteracts the inhibitory action of polyphenols on iron absorption, and to explore the mechanisms of polyphenol-mediated apical iron uptake and ...

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

    Directory of Open Access Journals (Sweden)

    Yukihiro Takahashi

    2013-09-01

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Ramin SALEH JOUNEGHANI; Dolatabadian, Aria

    2009-01-01

    The role of ascorbic acid as a key molecule antioxidant involves in biotic and abiotic stress has already been well described. Recent study indicates that it also participates in the detoxification of generated reactive oxygen species due to abiotic stresses. Thus, In order to study effects of salt stress and ascorbic acid on antioxidant enzyme activity, chlorophyll content, lipid peroxidation and abscisic acid accumulation of bean an experiment was conducted. The exogenous application of asc...

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

    Directory of Open Access Journals (Sweden)

    Farouk S.

    2011-09-01

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

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

    OpenAIRE

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

    2004-01-01

    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...

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

    Science.gov (United States)

    Jo, Ara; Kang, Minkyung; Cha, Areum; Jang, Hye Su; Shim, Jun Ho; Lee, Nam-Suk; Kim, Myung Hwa; Lee, Youngmi; Lee, Chongmok

    2014-03-28

    We report a new nonenzymatic amperometric detection of ascorbic acid (AA) using a glassy carbon (GC) disk electrode modified with hollow gold/ruthenium (hAu-Ru) nanoshells, which exhibited decent sensing characteristics. The hAu-Ru nanoshells were prepared by the incorporation of Ru on hollow gold (hAu) nanoshells from Co nanoparticle templates, which enabled AA selectivity against glucose without aid of enzyme or membrane. The structure and electrocatalytic activities of the hAu-Ru catalysts were characterized by spectroscopic and electrochemical techniques. The hAu-Ru loaded on GC electrode (hAu-Ru/GC) showed sensitivity of 426 ?A mM(-1) cm(-2) (normalized to the GC disk area) for the linear dynamic range of electrode displayed remarkable selectivity for ascorbic acid over all potential biological interferents, including glucose, uric acid (UA), dopamine (DA), 4-acetamidophenol (AP), and nicotinamide adenine dinucleotide (NADH), which could be especially good for biological sensing. PMID:24636416

  13. Effect of previous ascorbic acid treatment on the fatty acid profile of cobia (Rachycentron canadum fillets during frozen storage

    Directory of Open Access Journals (Sweden)

    Aftabsavar, Y.

    2012-03-01

    Full Text Available The present research focuses on the nutritional value of the lipid retention associated with frozen cobia (Rachycentron canadum. The effect of a previous soaking in an aqueous ascorbic acid (AA solution on the fatty acid profile of fish fillets during a further frozen storage period (–18 °C was investigated. Two different AA concentrations were tested (0.25% and 0.50% and compared to control conditions. As a result of the frozen storage period (up to 6 months, marked decreases were found in the contents of fatty acid groups such as monounsaturated, polyunsaturated and n-3 polyunsaturated, as well as in the n-3/n-6 ratio. However, a preserving effect on such fatty acid parameters could be observed resulting from the previous AA treatment, which was greater when applying the 0.50% AA concentration. Assessment of the polyene index indicated an increased lipid oxidation development during the frozen storage time; this increase was partially inhibited by the previous AA soaking.Este estudio se centra en el valor nutricional lipídico de cobia (Rachycentron canadum congelada. Para ello, se investiga el efecto que un tratamiento previo con ácido ascórbico (AA puede tener sobre el perfil de ácidos grasos de filete de pescado durante su conservación en congelación (–18 °C; seis meses. Se aplicaron dos concentraciones de AA (0.25% y 0.50% que fueron comparadas con muestras control. Como resultado de la conservación en congelación, se observó un descenso importante en grupos de ácidos grasos monoinsaturados, poliinsaturados y poliinsaturados de las serie n-3, así como en la relación n-3/n-6. Sin embargo, el tratamiento previo con AA produjo un efecto protector en estos parámetros, siendo mayor al aplicar AA en la concentración superior. La medida del índice de polienos reflejó un incremento de la oxidación lipídica durante la conservación en congelación; este incremento fue parcialmente inhibido como resultado del tratamiento previo con AA.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-01

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

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

    International Nuclear Information System (INIS)

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

  16. 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)

  17. Effects of ascorbic acid on cell mediated, humoral immune response and pathophysiology of

    Directory of Open Access Journals (Sweden)

    Suchint Simaraks

    2003-05-01

    Full Text Available The purpose of this study was to conduct an experiment related to the effects of chronic heat stress on total white blood cell changes, pathophysiology of leukocyte and effects of ascorbic acid on lymphocytes, lympholytic cells and humoral immunity of New-castle disease of broilers under chronic heat stress. Randomized complete block was the design. One hundred-forty-four chickens were maintained at 33+1 oC environmental temperature and on four levels of added ascorbic acid i.e. 0 (control group, 200, 400 and 800 mg/kg in dietsfor 21 days. On days 1, 3, 7, 14 and 21 of the experimental period, total white blood cells count, lympholytic cell and HI titer for Newcastle disease were determined. On day 21, histopathology of lung, liver, kidney, heart and bursa of fabricius of randomly selected broilers (n=36; 3 birds per experimental unit were studied. Total white blood cells (TWBC of the birds were significantly increased on day 3 (P<0.05 and were higheston days 7 and 14 then significantly decreased on days 21 (P<0.05. Monocytes were significantly increased on day 3 (P<0.05. Lymphocytes were significantly increased on day 7, and were highest on day 14 (P<0.05. On day 21, the value of lymphocyte was significantly lower than on days 7 and 14 (P<0.05, respectively. Lympholytic cells were significantly increased on day 3 and 7 (P<0.05, respectively, but on day 21, lympholyticcells were significantly decreased to lower value than on day 7 (P<0.05. Heterophils were significantly increased on day 3 and 7 and then decreased on day 14 (P<0.05. Tissue injury and hemorrhage in broilers under chronic heat stress caused leukocytosis, heterophilia, lympholysis and monocytosis. The size of lobules within the bursa of fabricius in broilers receiving ascorbic acid at 800 mg/kg in the diet were larger than inbirds that received added ascorbic acid at 400, 200 and 0 mg/kg in their diets, respectively. Lymphocytes and lympholytic cells were not significantly different among the ascorbic acid treatment groups. Besides, HI titers of Newcastle disease at 800 mg/kg in the diet were significantly higher than the others (P<0.05. Apparently, adding ascorbic acid at 800 mg/kg in the diet could improve humoral immunity in broilers under heat stress.

  18. Effect of Acridine and Ascorbic Acid on Rhizobia of Legume Trees

    Directory of Open Access Journals (Sweden)

    El-Adl

    2001-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    M.A. Nassef

    2002-01-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

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

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

    International Nuclear Information System (INIS)

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

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

    Scientific Electronic Library Online (English)

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

    2012-10-01

    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 pe [...] pper with 45% humidity. The experiments were carried out using the peppers cut in half, with and without osmotic pre-treatment, followed by drying in an oven at 70 ºC. The results showed that the osmotic pretreatment did not influence the retention of ascorbic acid during the drying of pepper. The sensory analysis regarding the color, flavor, and texture attributes revealed that there was no difference in the acceptability.

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

    Science.gov (United States)

    Hernández-Herrero, J A; Frutos, M J

    2015-04-15

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

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

    Directory of Open Access Journals (Sweden)

    Supranee MANURAKCHINAKORN

    2004-06-01

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

  6. Biocompatible water-in-oil emulsion as a model to study ascorbic acid effect on lipid oxidation.

    Science.gov (United States)

    Mosca, Monica; Ceglie, Andrea; Ambrosone, Luigi

    2008-04-17

    A biocompatible water-in-oil (W/O) emulsion has been used as a model to study the effect of ascorbic acid (AA) on the oxidation of the oil (glycerol trioleate, GTO) continuous phase. The model system consisted of 3 wt % water dispersed in GTO containing 0.5 wt % sodium oleate (NaO)/oleic acid (OA) mixture (NaO/OA = 20/80 mol/mol %) as a stabilizer. To study the ascorbic acid effect on GTO light-promoted oxidation, we added aqueous solutions of ascorbic acid to GTO in place of distilled water. Results obtained as peroxide values show that ascorbic acid activity depends on its concentration and it is affected by the characteristics of the W/O interface. In the presence of ascorbyl palmitate (AP) or sorbitan trioleate (Span 85) in the continuous phase, ascorbic acid activity increases in the first few hours of oxidation. The effect of ascorbic acid has been related to emulsion structure by calculating characteristic parameters of the droplet size distributions by means of optical microscopy. PMID:18358026

  7. Development of a reference material for L-ascorbic acid in fruits and vegetables

    OpenAIRE

    Valente, A.; Sanches-Silva, A.; Albuquerque, T.G.; Costa, H. S.

    2011-01-01

    INTRODUCTION: Ascorbic acid (AA) is a water soluble vitamin that plays a determinant role in the defense against cellular damage through its antioxidant activity. Fresh fruits and vegetables are the main natural sources of AA. Economic, rapid, accurate and sensitive methods for laboratory analysis are needed to improve the quality of analytical data. Regular use of a reference material and participation in a proficiency testing schemes are helpful to evaluate the performance of laboratories a...

  8. Oxidative stress, ?-tocopherol, ascorbic acid and reduced glutathione status in schizophrenics

    OpenAIRE

    Dadheech, Gora; Mishra, Sandhya; Gautam, Shiv; Sharma, Praveen

    2006-01-01

    A disturbance in the antioxidant defense system including ?-tocopherol, ascorbic acid and reduced glutahtione metabolism due to free radical induced oxidative injury has been implicated in various neuro-psychiatric disorders. The roles of these antioxidants, changes in their blood levels and correlation with oxidative stress were studied in a common psychiatric illness Schizophrenia. Fifty-eight subjects of either sex ranging in age from 18–60 years divided into two age groups (?40 and >...

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

    OpenAIRE

    Samina Malik and Muhammad Ashraf

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

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

    2010-01-01

    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 t...

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

    OpenAIRE

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

    2007-01-01

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

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

    OpenAIRE

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

    2003-01-01

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

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

    Scientific Electronic Library Online (English)

    Martín Roberto, Alvarez; Fernando Osvaldo, Kravetz.

    2009-06-01

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

  15. Simultaneous determination of ascorbic acid, dopamine, uric acid, and tryptophan by nanocrystalline ZSM-5 modified electrodes.

    Science.gov (United States)

    Kaur, Balwinder; Srivastava, Rajendra

    2014-09-01

    Nanocrystalline ZSM-5 was prepared by using propyltriethoxysilane as an additive in the conventional ZSM-5 synthesis composition. Materials were characterized by a complementary combination of X-ray diffraction, nitrogen sorption, and Scanning electron microscopy. Transition metal ion exchanged nanocrystalline ZSM-5 (M-Nano-ZSM-5, where M = Cu2+, Ni2+, Co2+, Fe2+, and Mn2+) modified electrodes were constructed for the simultaneous determination of ascorbic acid (AA), dopamine (DA), uric acid (UA), and tryptophan (Trp). Electrochemical studies were carried out by using cyclic voltammetry, linear sweep voltammetry, and chronoamperometry in buffer solution at pH 3.5. Fe-Nano-ZSM-5 modified electrode exhibited excellent electrocatalytic activity with well-separated oxidation peaks towards AA, DA, UA, and Trp in their simultaneous determination. Among the M-Nano-ZSM-5 and transition metal ion-exchanged ZSM-5 (M-ZSM-5) materials investigated in this study, Fe-Nano-ZSM-5 exhibited the highest catalytic activities towards the oxidation of AA, DA, UA, and Trp with good stability, sensitivity, and selectivity. The analytical performance of this sensor was demonstrated for the simultaneous determination of AA, DA, UA, and Trp in blood serum and UA concentration in urine samples. PMID:25924298

  16. Novel graphene flowers modified carbon fibers for simultaneous determination of ascorbic acid, dopamine and uric acid.

    Science.gov (United States)

    Du, Jiao; Yue, Ruirui; Ren, Fangfang; Yao, Zhangquan; Jiang, Fengxing; Yang, Ping; Du, Yukou

    2014-03-15

    A novel and sensitive carbon fiber electrode (CFE) modified by graphene flowers was prepared and used to simultaneously determine ascorbic acid (AA), dopamine (DA) and uric acid (UA). SEM images showed that beautiful and layer-petal graphene flowers homogeneously bloomed on the surface of CFE. Moreover, sharp and obvious oxidation peaks were found at the obtained electrode when compared with CFE and glassy carbon electrode (GCE) for the oxidation of AA, DA and UA. Also, the linear calibration plots for AA, DA and UA were observed, respectively, in the ranges of 45.4-1489.23 ?M, 0.7-45.21 ?M and 3.78-183.87 ?M in the individual detection of each component. By simultaneously changing the concentrations of AA, DA and UA, their oxidation peaks appeared at -0.05 V, 0.16 V and 2.6 V, and the good linear responses ranges were 73.52-2305.53 ?M, 1.36-125.69 ?M and 3.98-371.49 ?M, respectively. In addition, the obtained electrode showed satisfactory results when applied to the determination of AA, DA and UA in urine and serum samples. PMID:24140872

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

    Science.gov (United States)

    Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia; Lu, Xiaoquan; Zhou, Xibin

    2014-05-01

    A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via ?-? conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA-DA, DA-UA and UA-AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2-12.9 mM, 0.5-110 ?M, and 10-1000 ?M, with the detection limits (S/N=3) of 10.09 ?M, 0.29 ?M and 1.24 ?M, respectively. Furthermore, the modified electrode was investigated for real sample analysis. PMID:24746351

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

    Scientific Electronic Library Online (English)

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

    2013-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Liviu Fartaies

    2009-06-01

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

  20. 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)

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  4. 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

  5. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-04

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

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

    Science.gov (United States)

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

    2013-11-01

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

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

    Science.gov (United States)

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

    2015-01-01

    Gold nanoparticle/graphene (GNP/GR) nanocomposite was one-pot synthesized from water soluble graphene and HAuCl4 by hydrothermal method and characterized by TEM, Raman spectroscopy, XRD, XPS, UV-vis spectroscopy, and electrochemical impedance spectroscopy (EIS). Electrogenerated chemiluminescence (ECL) of luminol was investigated at the GNP/GR modified glassy carbon electrode (GNP/GR/GCE) and the GNP modified glassy carbon electrode (GNP/GCE) in aqueous solution respectively. The results revealed that one strong anodic ECL peak could be observed at ?0.8 V at two modified electrodes compared with that at the bare electrode. The intensity of the anodic ECL at the GNP/GR/GCE is weaker than that at the GNP/GCE, which should be due to the synergic effect of the enhancing effect of gold nanoparticles and the inhibiting effect of graphene on anodic luminol ECL. One strong cathodic ECL peak located at ?-0.8 V could be observed at the GNP/GR/GCE but not at the GNP/GCE, which should be result from the adsorbed oxygen at the graphene film. In the presence of ascorbic acid, the anodic ECL at the GNP/GR/GCE was enhanced more than 8-times, which is more apparent than that at the GNP/GCE. Whereas, the cathodic ECL peak was seriously inhibited at the GNP/GR/GCE. The enhanced ECL intensity at the GNP/GR/GCE varied linearly with the logarithm of ascorbic acid concentration in the range of 1.0 × 10-8 to 1.0 × 10-6 mol L-1 with a detection limit of 1.0 × 10-9 mol L-1. The possible ECL mechanism was also discussed.

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

    Science.gov (United States)

    Alagl, Adel S; Bhat, Subraya Giliyar

    2015-03-01

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

  10. Effects of co-supplementation of iron with ascorbic acid on antioxidant--pro-oxidant balance in the guinea pig.

    Science.gov (United States)

    Collis, C S; Yang, M; Diplock, A T; Hallinan, T; Rice-Evans, C A

    1997-07-01

    The relationship between intake of iron with ascorbic acid and their uptake into the plasma and liver of guinea pigs was studied. The influence on the antioxidant/pro-oxidant balance of liver microsomes was also determined. Animals were fed a standard pelleted diet low in iron and ascorbic acid for 35 days. The pellet diet was supplemented by oral dosing with a solution containing either maintenance dietary levels of ascorbic acid and iron, or one of three regimens that increased the dosage of these substances ten fold. There were no significant differences in animal growth rate or food intake between these regimens. Liver and plasma total ascorbate levels were significantly increased (p < 0.05) in animals receiving either ascorbic acid alone (liver 126 +/- 36 micrograms/g tissue wet wt. and plasma 51.7 +/- 17.0 microM; n = 9) or ascorbic acid and iron (105 +/- 18 micrograms/g and 40.3 +/- 15.3.0 microM; n = 8) compared to controls (84 +/- 36 micrograms/g and 15.3 +/- 8.5 microM; n = 11). Total iron levels in the liver (76.7 +/- 7.3 micrograms/g; control; n = 6) and plasma (2.4 +/- 0.03 mg/l; control) were not significantly raised in animals under these conditions of iron or ascorbate intake. Liver microsomes isolated from animals receiving iron had a greater susceptibility to oxidative stress in terms of malondialdehyde production during auto-oxidation compared to those from control animals under the same conditions. This effect was eliminated on combining ascorbic acid with the iron supplementation, suggesting that oral administration of vitamin C has a protective rather than a pro-oxidant effect under these circumstances. PMID:9269586

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

    Science.gov (United States)

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

    2013-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-08-30

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Larissa Akemi Ywassaki; Solange Guidolin Canniatti-Brazaca

    2011-01-01

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

  19. Effect of Ocimum sanctum, ascorbic acid, and verapamil on macrophage function and oxidative stress in mice exposed to cocaine

    OpenAIRE

    Bhattacharya S; Rathi N; Mahajan P; Tripathi A; Paudel K; Rauniar G; Das B

    2009-01-01

    Objective: To investigate the effect of Ocimum sanctum, ascorbic acid, and verapamil on macrophage function and oxidative stress in experimental animals exposed to cocaine. Materials and Methods: Mice were used in this study and were divided randomly into different groups of six animals each. They were either treated with intraperitoneal injection of saline or cocaine hydrochloride or an oral feeding of oil of Ocimum sanctum, ascorbic acid or verapamil, or both (ascorbic acid and verapamil...

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

    OpenAIRE

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

    2013-01-01

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

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

    OpenAIRE

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2015-03-01

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

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

    Directory of Open Access Journals (Sweden)

    HAMIDAH HAMAMA

    2010-09-01

    Full Text Available This study was conducted in the laboratory and the field to examine the effects of ascorbic acid treatment on germination and seedling growth under drought stress. The laboratory works consisted of two experiments and were designed to determine the critical osmotic potential of maize and to determine the optimum ascorbic acid concentration. The field study was designed to examine the effects of soaking seed in ascorbic acid on seedling growth under drought stress. Drought condition was simulated by PEG-6000 and regulation of water treatment. During the first experiment, interactions of both osmotic potential and varieties were significant at all variables. Germination percentage and speed of germination were significantly decreased by increasing of osmotic potential. The second experiment showed that interactions of both factors were significant at all variables except vigor index, the length of shoot, primary, and seminal root. The results showed that the ascorbic acid treatment improved the germination percentage, the speed of germination and the vigor index compared with the control, besides the increase in length of shoot, primary and seminal root and number of seminal root. However, the best result was showed by 55 mM ascobic acid. The result of field experiment showed that interactions were not always significant and 55 mM ascorbic acid treatment increased the seedling height, the number of leaves and leaf area but it had no effect on the water deficit and the root length.

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

    Directory of Open Access Journals (Sweden)

    Pedro Alves de SOUZA

    2001-12-01

    Full Text Available The egg quality may be influenced by some nutrients added to laying hens diets and among these nutrients, the ascorbic acid is included. According to some researches, this acid, besides of improving the quality, it can increase the egg production and weight. In addition, it reduces the quantity of cracked eggs and food intake. In order to contribute with more information, this experiment was developed. Concentrations of 100; 150 and 200mg/kg of ascorbic acid were added to rations of laying hens during 60 days, with the objective of determining the influence of ascorbic acid on the quality of eggs kept under room temperature conditions (26.7 ± 2.2°C and 60 ± 5% moisture for a period of 28 days. A total of 1440 eggs were used, being 720 of white shell and 720 of brown shell. Egg quality was determined by Haugh unit and yolk index, every 7 days. The obtained results allowed to conclude that ascorbic acid, independent on the level of supplementation, was not enough to decrease.A qualidade dos ovos pode ser influenciada por alguns nutrientes adicionados à dieta das aves e entre esses nutrientes se inclui o ácido ascórbico, que segundo alguns pesquisadores, além de melhorar a qualidade, pode aumentar a produção e o peso dos ovos e diminuir a quantidade de ovos trincados e o consumo de ração. Com a finalidade de tentar contribuir com mais algumas informações, desenvolveu esse experimento com o objetivo de avaliar a influência do ácido ascórbico sobre a qualidade de ovos brancos e marrons mantidos sob condições de ambiente (26,7 ± 2,2°C e 60 ± 5%UR, por um período de 28 dias. Foram utilizados 1440 ovos, sendo 720 de casca branca e 720 de casca marrom. Foram adicionadas à ração de aves, durante 60 dias, concentrações de 100, 150 e 200mg/kg de ácido ascórbico. A qualidade dos ovos foi determinada de 7 em 7 dias, avaliando-se a unidade Haugh e o índice gema. Os dados obtidos permitiram concluir que a suplementação com o ácido ascórbico não foi suficiente para diminuir a perda de qualidade dos ovos. Independentemente dos níveis de vitaminas utilizados, os ovos marrons mostraram-se qualitativamente superiores aos brancos.

  5. Neuronal damage and memory deficits after seizures are reversed by ascorbic acid? O dano neuronal e o déficit de memória após convulsões são revertidos pelo ácido ascórbico?

    OpenAIRE

    Adriana da Rocha Tomé; Chistiane Mendes Feitosa; Rivelilson Mendes de Freitas

    2010-01-01

    The objective of the present study was to evaluate the neuroprotective effects of ascorbic acid (AA) in rats, against the neuronal damage and memory deficit caused by seizures. Wistar rats were treated with 0.9% saline (i.p., control group), ascorbic acid (500 mg/kg, i.p., AA group), pilocarpine (400 mg/kg, i.p., pilocarpine group), and the association of ascorbic acid (500 mg/kg, i.p.) plus pilocarpine (400 mg/kg, i.p.), 30 min before of administration of ascorbic acid (AA plus pilocarpine g...

  6. Variation in the SLC23A1 gene does not influence cardiometabolic outcomes to the extent expected given its association with l-ascorbic acid1234

    OpenAIRE

    Wade, Kaitlin H; Forouhi, Nita G; Cook, Derek G.; Johnson, Paul; McConnachie, Alex; Morris, Richard W; Rodriguez, Santiago; Ye, Zheng; Ebrahim, Shah; Padmanabhan, Sandosh; Watt, Graham; Bruckdorfer, K Richard; Wareham, Nick J.; Whincup, Peter H.; Chanock, Stephen

    2014-01-01

    Background: Observational studies showed that circulating l-ascorbic acid (vitamin C) is inversely associated with cardiometabolic traits. However, these studies were susceptible to confounding and reverse causation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-15

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

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

    Directory of Open Access Journals (Sweden)

    Šimurina Olivera D.

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    I.V. Ogungbe

    2008-01-01

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

  10. Protective Effects of Extract from Dates (Phoenix Dactylifera L. and Ascorbic Acid on Thioacetamide-Induced Hepatotoxicity in Rats

    Directory of Open Access Journals (Sweden)

    Mohamed Bastway Ahmed

    2008-01-01

    Full Text Available The ameliorative activity of aqueous extract of the flesh of dates (Phoenix dactylifera L. and ascorbic acid on thioacetamide-induced hepatotoxicity was studied in rats. Sixty male rats were divided into six equal groups of 10. Two groups were controls, one treated with thioacetamide and one with only distilled water. Two groups received extract of flesh Phoenix dactylifera and intraperitoneal (IP thioacetamide (400 mg/kg either before or after administration of flesh extract. Two groups received ascorbic acid and intraperitoneal (IP thioacetamide (400 mg/kg b.wt. either before or after administration of ascorbic acid. Liver damage was assessed by estimation of plasma concentration of bilirubin and enzymes activities of aspartate aminotransferase (AST, alanine aminotransferase ( ALT, lactate dehydrogenase (LDH, ? glutamyl transferase and alkaline phosphatase and serum alpha fetoprotein and serum total testosterone. Treatment with aqueous extract of date flesh or by ascorbic acid significantly reduced thioacetamide-induced elevation in plasma bilirubin concentration and enzymes. This study suggests that thioacetamide-induced liver damage in rats can be ameliorated by administration of extract of date flesh and ascorbic acid.

  11. The Effect of Ascorbic Acid and Sodium Stearoyl -2- Lactylate on Frozen Dough Stability

    OpenAIRE

    Koca, Ahmet Faik; ANIL, Münir

    1999-01-01

    The present study consitst of two parts of research. In the first part, the effect of varying doses of ascorbic acid (AA-0, 75 and 125 ppm) and sodium stearoyl -2- lactylate (SSL-0, 0.5 %) used in frozen doughs on bread characteristics after 2 months storage period. In the second part the effect AA alone and AA+SSL after three cycles of freeze-thaw on proof time and bread char-acteristics was investigated. The results are presented below statisticaly (p

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

    OpenAIRE

    Samuel Tilahun; Pandiyan Paramaguru; Kandhasamy Rajamani

    2013-01-01

    Capsaicin and ascorbic acid contents of seven Indian peppers varieties/accessions from Capsicum annuum (CA 97, CCH, K1, KTPL19, Arka Abhir and Bayadagi Kaddi) and C. frutescens (CF1) species were determined using High Performance Liquid Chromatography (HPLC). Based on their pungency value, all the chilli accession/varieties (CA 97, CCH, K1, and CF 1) were classified as highly pungent peppers. The accession CF1 showed the highest concentration of capsaicin (445mg 100g -1 DW) with corresponding...

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

    OpenAIRE

    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

    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 ...

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

    DEFF Research Database (Denmark)

    Mariotti, Salomé; Granby, Kit

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

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

    Directory of Open Access Journals (Sweden)

    Korychenska O.

    2013-09-01

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

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

    International Nuclear Information System (INIS)

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

  17. Ion exchange separation of 90Y from 90Sr using ascorbic acid and nitrilotriacetic acid as eluents

    International Nuclear Information System (INIS)

    A simple ion exhange procedure for clean separation of the biomedically important radionuclide, 90Y, in the equilibrium mixture, 90Sr-90Y, is demonstrated. Separation of 90Y in the carrier-free state was achieved by preferential elution of the radiotracer through a cation exchange resin column of Dowex-50W-X8 with freshly prepared Na-ascorbate solution of 90Y was verified by taking recourse to the studies of beta decay curves. The procedure developed has the added advantage that the complexing reagent, ascorbic acid, itself has got its own biomedical importance as vitamin C and the technique can also conveniently be used as a generator for the isotope 90Y. (author)

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

    International Nuclear Information System (INIS)

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

  19. The ameliorative effect of ascorbic acid and Ginkgo biloba on learning and memory deficits associated with fluoride exposure

    Science.gov (United States)

    Raghuveer, Vasudeva C.; Rao, Mallikarjuna C.; Somayaji, Nagabhooshana S.; Babu, Prakash B.

    2013-01-01

    Chronic exposure to fluoride causes dental and skeletal fluorosis. Fluoride exposure is also detrimental to soft tissues and organs. The present study aimed at evaluation of the effect of Ginkgo biloba and ascorbic acid on learning and memory deficits caused by fluoride exposure. Male Wistar rats were divided into five groups (n=6). Group 1 control. Groups 2 to 5 received 100 ppm of sodium fluoride over 30 days. Groups 3, 4 and 5 were further treated for 15 days receiving respectively 1% gum acacia solution, 100 mg/kg body weight ascorbic acid, and 100mg/kg body weight Ginkgo biloba extract. After 45 days, all animals were subjected to behavioural tests. The results showed that fluoride affected learning and memory. Fluoride causes oxidative stress and neurodegeneration, thereby affecting learning and memory. Ascorbic acid and Ginkgo biloba were found to augment the reversal of learning and memory deficits caused by fluoride ingestion. PMID:24678261

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

    International Nuclear Information System (INIS)

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

  1. Investigating Ascorbic Acid Effect in Prevention of CIN in Diabetic Patients

    Directory of Open Access Journals (Sweden)

    Nough

    2013-06-01

    Full Text Available Introduction: Contrast induced nephropathy (CIN is one the complications resulting from coronary catheterization and is regarded as one of the reasons of acute kidney failure. Therefore, this study aimed to investigate the effect of ascorbic acid in the prevention of CIN in Yazd in 2012. Methods: This study involves a double blind clinical trial in which 90 Diabetic patients with coronary catheterization have attended. The patients were divided randomly into two groups: control group and treatment group. Demographic and clinical data were collected by a questionnaire. Treatment group received vitamin C (2 grams 2 hours before the intervention and the control groups were given 2 grams of the Placebo. The GFR (Glomerular filtration rate, BUN (Blood Urea Nitrogen, and Cr (Creatinin were measured and compared after 2-3 days. Results: The CIN in treatment group was about 3 patients (7.7% and was 7 (16.7% in the control group. Thus, no significant difference was observed; though, there was a significant difference between Cr and GFR before and after the treatment in vitamin C group (PV= 0.006, PV=0.001, but these differences were not significant in the placebo group.(PV=0.661, PV=0.747. Moreover, considering the participants’ age, sex and their primary function of kidney, a significant difference had not appeared due to the incidence of CIN between the two groups. Conclusion: Our study did not show Ascorbic Acid effects in prevention of CIN in Diabetic patients.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

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

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

    Directory of Open Access Journals (Sweden)

    Veturia-Ileana Nueleanu

    2008-03-01

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

  5. Quantification of vitamin C requirements for juvenile shrimp (Penaeus monodon) using polyphosphorylated L-ascorbic acid.

    Science.gov (United States)

    Chen, H Y; Chang, C F

    1994-10-01

    The vitamin C requirements of marine shrimp (Penaeus monodon) for optimal growth were evaluated in a 15-wk feeding trial using polyphosphorylated L-ascorbic acid (C2PP), a stable derivative of L-ascorbic acid (C1). Juvenile shrimp (0.55 +/- 0.01 g) were fed purified diets containing graded levels (0, 50, 100, 200 and 400 mg/kg diet) of supplemental C2PP or a high dosage of C1 (2500 mg/kg diet). Their weight gain, survival, feed efficiency and C1 storage in hepatopancreas and muscle were used to quantify the requirements. The growth of the shrimp fed the unsupplemented diet was significantly lower than those of the supplemented groups except the 100 mg C2PP/kg diet group. The C1 concentrations in muscle and hepatopancreas were greatest in shrimp fed 200 or 400 C2PP mg/kg diet. The dietary level required for juvenile P. monodon was found to be 209 mg/kg diet, based on the broken-line model analysis of weight gain, and was 220 mg/kg diet and 210 mg/kg diet, based on the analyses of C1 concentrations of hepatopancreas and muscle, respectively. Shrimp fed unsupplemented diet showed a significantly higher mortality than the supplemented groups. Most of the shrimp in the unsupplemented group that died suffered incomplete molting. No other overt deficiency sign was observed in any group. PMID:7931713

  6. Effect of Ocimum sanctum, ascorbic acid, and verapamil on macrophage function and oxidative stress in mice exposed to cocaine

    Directory of Open Access Journals (Sweden)

    Bhattacharya S

    2009-01-01

    Full Text Available Objective: To investigate the effect of Ocimum sanctum, ascorbic acid, and verapamil on macrophage function and oxidative stress in experimental animals exposed to cocaine. Materials and Methods: Mice were used in this study and were divided randomly into different groups of six animals each. They were either treated with intraperitoneal injection of saline or cocaine hydrochloride or an oral feeding of oil of Ocimum sanctum, ascorbic acid or verapamil, or both (ascorbic acid and verapamil, and were evaluated for a respiratory burst of macrophages, superoxide and nitric oxide (NO production, estimation of TNF-a in the serum and supernatant of cultured macrophages, estimation of lipid peroxidation (malondialdehyde- MDA in the serum, and superoxide dismutase activity in the erythrocytes. Results: Unstimulated respiratory burst as well as superoxide production was enhanced on treatment with cocaine and all the three drugs were found to attenuate this enhancement. The bactericidal capacity of macrophages decreased significantly on chronic cocaine exposure, as it was associated with decreased respiratory burst and superoxide production. There was a significant decrease in NO production by macrophages on chronic cocaine exposure and all the test drugs were found to restore nitrite formation to a normal level. There was an increase in the malonylodialdehyde (MDA level and decrease in the superoxide dismutase level on chronic cocaine exposure, and all the three drugs effectively decreased the MDA level and increased superoxide dismutase level. There was an increase in serum TNF-? on chronic cocaine exposure, which was decreased significantly by ascorbic acid and verapamil. Conclusion: O. sanctum, ascorbic acid, and verapamil were equally effective in improving the macrophage function and reducing oxidative stress. These findings suggested that O. sanctum, ascorbic acid, and verapamil attenuated acute and chronic cocaine-mediated effects.

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

    Science.gov (United States)

    Bahçeci, K Sava?; Acar, Jale

    2007-12-15

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

  8. Blanching and Drying Behavior of Dioscorea schimperiana and Impact on Cellular Exchanges and on Calcium, Ascorbic Acid and ?-carotene Contents

    Directory of Open Access Journals (Sweden)

    R. Ndjouenkeu

    2011-01-01

    Full Text Available The influence of blanching parameters (time and temperature, variety and yam thickness on cellular exchanges and on calcium, ascorbic acid and ?-carotene contents during blanching and/or subsequent drying was investigated. Yam slices (2, 3 and 4 mm thickness of the yellow and orange variety of D. schimperiana were blanched in hot water at 70 and 100°C for 0 to 60 sec in order to study the cellular exchange during blanching. Kinetic of calcium loss was determined during blanching at 100°C. Yams slices of the orange variety blanched at 100°C for one minute were dried at 50°C in a cross flow cabinet dryer. Losses in ?-carotene and ascorbic acid were calculated after one minute of blanching at 100°C and along the drying process. The results show a strong intraspecific variability in cellular exchange during blanching. Blanching in hot water at 100°C result in a higher loss in calcium, ?-carotene and ascorbic acid. These losses continue during subsequent drying. The moisture diffusivity during drying of blanched slices varied from 1.07x10-10 (4 mm to 4.33x10-11 (2 mm. Twenty six to fifty percent of the ?-carotene and more than 50% of ascorbic acid were loss during blanching depending upon slices thickness. Blanching is the limiting factor in ?-carotene and ascorbic acid loss during blanching and subsequent air drying. Blanching parameters (temperature and time, slices thickness and variety influenced cellular exchanges and losses in calcium, ?-carotene and ascorbic acid.

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

    Directory of Open Access Journals (Sweden)

    Mousavi M

    2007-04-01

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

  10. Boric acid and boronic acids inhibition of pigeonpea urease.

    Science.gov (United States)

    Reddy, K Ravi Charan; Kayastha, Arvind M

    2006-08-01

    Urease from the seeds of pigeonpea was competitively inhibited by boric acid, butylboronic acid, phenylboronic acid, and 4-bromophenylboronic acid; 4-bromophenylboronic acid being the strongest inhibitor, followed by boric acid > butylboronic acid > phenylboronic acid, respectively. Urease inhibition by boric acid is maximal at acidic pH (5.0) and minimal at alkaline pH (10.0), i.e., the trigonal planar B(OH)3 form is a more effective inhibitor than the tetrahedral B(OH)4 -anionic form. Similarly, the anionic form of phenylboronic acid was least inhibiting in nature. PMID:17059182

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

    OpenAIRE

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

    2009-01-01

    The proximate composition, ascorbic acid and heavy metal content of (African walnut) Tetracarpidium conophorum were evaluated using chemical analysis. The result of the proximate composition showed the following; moisture (48.70%), carbohydrate (53.20%), crude protein (35.22%), crude fat (6.21%), crude fiber (3.34%) and ash (2.03%).It also contained 53.50mg/100ml of ascorbic acid. The heavy metal concentrations in the fruit is Fe (0.064ppm), Mn (0.012ppm), Cr (0.001ppm), Ni (0.005ppm) ...

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

    Directory of Open Access Journals (Sweden)

    Marjanovi? Nikola J.

    2009-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    F. Ghazi

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Aurel Pisoschi

    2011-02-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-02

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

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

    Larsen, Sofus C; Angquist, Lars

    2014-01-01

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

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

    DEFF Research Database (Denmark)

    Larsen, Sofus C; Angquist, Lars

    2014-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Zhousheng Yang

    2003-10-01

    Full Text Available Poly (acridine red modified glassy carbon electrode was used for the detection of dopamine in the presence of ascorbic acid in a pH 7.4 phosphate buffer solutions (PBS by cyclic voltammetry and differential pulse voltammetry. The major difficulty of the overlapped oxidation potential of ascorbic acid could be overcome through the distinct attractive ability of poly (acridine red film to cationic dopamine and anionic ascorbic acid. The results showed that the dopamine anodic peak current and the concentration of dopamine had a linear relationship in the range of 1.0×10-7 ~ 1.0×10-4 mol dm-3. The detection limit (S/N=3 obtained by differential pulse voltammetry was 1.0×10-9 mol dm-3. The relative standard deviation of 10 successive scans was 2.07 % for 1.0×10-6 mol dm-3 DA. Ascorbic acid had hardly interference with the determination of dopamine. The proposed method exhibits good recovery and reproducibility.

  6. Ionic Strength Effect on the Rate of Reduction of Hexacyanoferrate (III) by Ascorbic Acid: A Physical Chemistry Laboratory Experiment.

    Science.gov (United States)

    Watkins, Kenneth W.; Olson, June A.

    1980-01-01

    Describes a physical chemistry experiment that allows students to test the effect of ionic strength on the rates of a reaction between ions. The reduction of hexacyanoferrate III by ascorbic acid is detailed. Comparisons with the iodine clock reaction are made. (CS)

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

    Directory of Open Access Journals (Sweden)

    J. Mirabdollbaghi

    2006-01-01

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

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

    DEFF Research Database (Denmark)

    Thorn, N A; Nielsen, F S

    1986-01-01

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

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

    Scientific Electronic Library Online (English)

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

    1821-18-01

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

  10. Suppressive effect of ascorbic acid on the mutagenesis induced by the bystander effect through mitochondrial function.

    Science.gov (United States)

    Kashino, G; Tamari, Y; Kumagai, J; Tano, K; Watanabe, M

    2013-07-01

    Here, we focused on suppressive effect of ascorbic acid (AsA) on changes in mitochondrial function and mutagenesis by the radiation- induced bystander effect (RIBE). In mammalian cell lines, medium transfer assay was performed and conditioned medium including secreted factors after X-irradiation were examined to detect the RIBE. We found that the membrane potential and increased levels of superoxide radical (O2(-)) in mitochondria were modulated in cells treated with conditioned medium from irradiated cells. The result of the present study also demonstrated that increases in reactive oxygen species (ROS) levels led to the induction of gene mutations. Interestingly, the modulations in mitochondria, in addition to mutation inductions by RIBE, were completely suppressed by treatment with AsA in cells treated with conditioned medium. These results suggest that mutagenesis, which may have resulted from secreted factors involving the RIBE, may be induced by ROS that are localized in mitochondria and may be relieved by AsA. PMID:23560693

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

    Science.gov (United States)

    Yoon, Soon-Do

    2014-02-26

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

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

    Science.gov (United States)

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

    2014-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-15

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  16. An unusual case of 'uncompetitive activation' by ascorbic acid: purification and kinetic properties of a myrosinase from Raphanus sativus seedlings.

    Science.gov (United States)

    Shikita, M; Fahey, J W; Golden, T R; Holtzclaw, W D; Talalay, P

    1999-08-01

    Myrosinase (thioglucoside glucohydrolase; EC 3.2.3.1) is a plant enzyme that hydrolyses glucosinolates, principally to isothiocyanates. Myrosinase was purified to homogeneity in good yield from 8-day-old seedlings of Raphanus sativus (daikon) using a four-step procedure involving chromatographies on anion exchange, hydrophobic Phenyl-Sepharose, gel filtration and concanavalin A-Sepharose. In order to stabilize the enzyme and to avoid excessive peak broadening during chromatography, 30% (v/v) glycerol was added to dialysis and chromatography buffers. The purified enzyme was eluted as a single peak from a gel-filtration sizing column with an apparent molecular mass of 120 kDa. The enzyme was resolved into two subunits with molecular masses of 61 and 62 kDa by SDS/PAGE. Ascorbic acid activated the purified enzyme more than 100-fold. The V(max) and K(m) values for the hydrolysis of allyl glucosinolate (sinigrin) were 2.06 micromol/min per mg of protein and 23 microM in the absence of ascorbate and 280 micromol/min per mg of protein and 250 microM in the presence of 500 microM ascorbate, respectively. As the ascorbate concentration was increased from 50 to 500 microM, the V(max) and K(m) values increased in parallel, and thus the V(max)/K(m) ratio remained constant. Similarly, raising the concentrations of sinigrin increased the concentration of ascorbic acid required for half-maximal activation (K(a)). At a sinigrin concentration of 250 microM, the K(a) for ascorbic acid was 55 microM. Sulphate, a reaction product, was a competitive inhibitor of activity, having a K(i) of 60 mM with respect to sinigrin and of 27 mM with respect to ascorbate. Thus activation of myrosinase from R. sativus by ascorbic acid exemplifies an unusual and possibly unique example of linear 'uncompetitive activation' (i.e. a proportionate increase in V(max) and K(m)) of an enzyme. The enzyme also had beta-glucosidase activity and hydrolysed p-nitrophenyl-beta-d-glucopyranoside. PMID:10417337

  17. Novel composite material polyoxovanadate@MIL-101(Cr): a highly efficient electrocatalyst for ascorbic acid oxidation.

    Science.gov (United States)

    Fernandes, Diana M; Barbosa, André D S; Pires, João; Balula, Salete S; Cunha-Silva, Luís; Freire, Cristina

    2013-12-26

    A novel hybrid composite material, PMo10V2@MIL-101 was prepared by the encapsulation of the tetra-butylammonium (TBA) salt of the vanadium-substituted phosphomolybdate [PMo10V2O40](5-) (PMo10V2) into the porous metal-organic framework (MOF) MIL-101(Cr). The materials characterization by powder X-ray diffraction, Fourier transform infrared spectra and scanning electron microscopy confirmed the preparation of the composite material without disruption of the MOF porous structure. Pyrolytic graphite electrodes modified with the original components (MIL-101(Cr), PMo10V2), and the composite material PMo10V2@MIL-101 were prepared and their electrochemical responses were studied by cyclic voltammetry. Surface confined redox processes were observed for all the immobilized materials. MIL-101(Cr) showed one-electron reduction process due to chromium centers (Cr(III) ? Cr(II)), while PMo10V2 presented five reduction processes: the peak at more positive potentials is attributed to two superimposed 1-electron vanadium reduction processes (V(V) ? V(IV)) and the other four peaks to Mo-centred two-electron reduction processes (Mo(VI) ? Mo(V)). The electrochemical behavior of the composite material PMo10V2@MIL-101 showed both MIL-101(Cr) and PMo10V2 redox features, although with the splitting of the two vanadium processes and the shift of the Mo- and Cr- centered processes to more negative potentials. Finally, PMo10V2@MIL-101 modified electrode showed outstanding enhanced vanadium-based electrocatalytic properties towards ascorbic acid oxidation, in comparison with the free PMo10V2, as a result of its immobilization into the porous structure of the MOF. Furthermore, PMo10V2@MIL-101 modified electrode showed successful simultaneous detection of ascorbic acid and dopamine. PMID:24308331

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

    Science.gov (United States)

    Jainu, Mallika; Mohan, Kunju Vijai

    2008-12-20

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

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

    Science.gov (United States)

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

    2015-01-01

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

  20. Ascorbic acid, alpha-tocopherol, and oregano supplements reduce stress-induced deterioration of chicken meat quality.

    Science.gov (United States)

    Young, J F; Stagsted, J; Jensen, S K; Karlsson, A H; Henckel, P

    2003-08-01

    In order to ameliorate a negative effect of stress on meat quality characteristics, chickens were fed a diet supplemented with a combination of ascorbic acid (1,000 ppm) and alpha-tocopherol (200 ppm) or oregano (3%), which has a high content of antioxidants. Chickens were slaughtered by cervical dislocation in the stable (no stress) or after transport and electrical stunning at the slaughter plant (stress). Activities of antioxidative enzymes (catalase, superoxide dismutase, and glutathion peroxidase) in pectoralis major (PM), iliotibialis (IL), and liver were unaffected by supplementation. However, erythrocyte stability, which is a more complex model system for determining oxidative status, increased with ascorbic acid-alpha-tocopherol supplementation and tended to increase after oregano supplementation. In nonstressed birds, this improved antioxidative status was reflected in decreased TBA-reactive substances (TBARS) in PM and liver of ascorbic acid-alpha-tocopherol-supplemented chickens and likewise in liver from oregano-supplemented chickens compared to that of nonstressed control birds. However, postmortem temperature, pH, and water-holding capacity were not affected by supplementation. Drip loss from oregano-supplemented chickens showed increased protein oxidation in specific bands, but this did not relate to water-holding capacity or antioxidative status. When exposed to stress, the concentration of TBARS in the control animals increased in PM and IL. Ascorbic acid-alpha-tocopherol supplementation protected IL, and oregano supplementation protected PM from stress-induced increases in TBARS. This differential effect between muscles may indicate differences in protection mechanisms. In conclusion, ascorbic acid-alpha-tocopherol and oregano supplements to chickens protect against stress-induced increase in TBARS, in different muscles. PMID:12943308

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

    Directory of Open Access Journals (Sweden)

    Dorival Martins

    2010-01-01

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

  2. Ascorbate and dehydroascorbic acid as reliable biomarkers of oxidative stress : analytical reproducibility and long-term stability of plasma samples subjected to acidic deproteinization

    DEFF Research Database (Denmark)

    Lykkesfeldt, Jens

    2007-01-01

    Lack of post-sampling stability of ascorbate and dehydroascorbic acid and failure to block their in vivo equilibrium have lowered their value as biomarkers of oxidative stress and limited the ability to further investigate their possible role in disease prevention. In the present paper, the analytical reproducibility was tested by repeated analysis of plasma aliquots from one individual over four years. The plasma was subjected to acidic deproteinization with an equal volume of 10% meta-phosphoric acid containing 2 mM EDTA and analyzed for ascorbate and dehydroascorbic acid by high-performance liquid chromatography with coulometric detection. In a parallel experiment, stability of human plasma samples treated as above and stored at -80°C for five years was tested in a cohort of 131 individuals. No degradation or shift in the equilibrium between ascorbate and dehydroascorbic acid was observed in either of the experiments. In conclusion, ascorbate and dehydroascorbic acid can be adequately preserved in plasma stored at -80°C following acidic deproteinization with meta-phosphoric acid containing 2 mM EDTA.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-18

    Graphical abstract: -- Abstract: Pharmacological doses of ascorbate were evaluated for its ability to potentiate the toxicity of sodium orthovanadate (Na{sub 3}VO{sub 4}) in tumor cells. Cytotoxicity, inhibition of cell proliferation, generation of ROS and DNA fragmentation were assessed in T24 cells. Na{sub 3}VO{sub 4} was cytotoxic against T24 cells (EC{sub 50} = 5.8 ?M at 24 h), but in the presence of ascorbate (100 ?M) the EC{sub 50} fell to 3.3 ?M. Na{sub 3}VO{sub 4} plus ascorbate caused a strong inhibition of cell proliferation (up to 20%) and increased the generation of ROS (4-fold). Na{sub 3}VO{sub 4} did not directly cleave plasmid DNA, at this aspect no synergism was found occurring between Na{sub 3}VO{sub 4} and ascorbate once the resulting action of the combination was no greater than that of both substances administered separately. Cells from Ehrlich ascites carcinoma-bearing mice were used to determine the activity of antioxidant enzymes, the extent of the oxidative damage and the type of cell death. Na{sub 3}VO{sub 4} alone, or combined with ascorbate, increased catalase activity, but only Na{sub 3}VO{sub 4} plus ascorbate increased superoxide dismutase activity (up to 4-fold). Oxidative damage on proteins and lipids was higher due to the treatment done with Na{sub 3}VO{sub 4} plus ascorbate (2–3-fold). Ascorbate potentiated apoptosis in tumor cells from mice treated with Na{sub 3}VO{sub 4}. The results indicate that pharmacological doses of ascorbate enhance the generation of ROS induced by Na{sub 3}VO{sub 4} in tumor cells causing inhibition of proliferation and apoptosis. Apoptosis induced by orthovanadate and ascorbate is closer related to inhibition on Bcl-xL and activation of Bax. Our data apparently rule out a mechanism of cell demise p53-dependent or related to Cdk2 impairment.

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

    Directory of Open Access Journals (Sweden)

    Sorina Ropciuc

    2011-10-01

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

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

    Science.gov (United States)

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

    2010-06-01

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

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

    International Nuclear Information System (INIS)

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

  7. Ascorbic acid does not affect the age-associated reduction in maximal cardiac output and oxygen consumption in healthy adults.

    Science.gov (United States)

    Bell, Christopher; Carson, John M; Motte, Nathaniel W; Seals, Douglas R

    2005-03-01

    Maximal aerobic capacity (Vo(2max)) decreases progressively with age, primarily because of a reduction in maximal cardiac output (Q(max)). This age-associated decline in Vo(2max) may be partially mediated by the development of oxidative stress that can suppress beta-adrenergic-receptor responsiveness and, consequently, reduce Q(max). To test this hypothesis, Vo(2max) (indirect calorimetry) and Q(max) (open-circuit acetylene breathing) were determined in 12 young (23 +/- 1 yr, mean +/- SE) and 10 older (61 +/- 1 yr) adults following systemic infusion of either saline (control) and/or the powerful antioxidant ascorbic acid (acute: bolus 0.06; drip 0.02 g/kg fat-free mass) and following chronic 30-day oral administration of ascorbic acid (500 mg/day). Plasma ascorbic acid concentration was not different between young and older adults and was increased similarly, independent of age [change (Delta) acute = 1,055 +/- 117%; Delta chronic = 62 +/- 19%]. Oxidized low-density lipoprotein concentration was greater (P < 0.001) in older (57 +/- 5 U/l) compared with young (34 +/- 3 U/l) adults and was reduced in both groups (P < 0.02) following acute (Delta = -6 +/- 2%) but not chronic (P = 0.18) ascorbic acid administration. Control (baseline) Vo(2max) and Q(max) were positively related (r = 0.76, P < 0.001) and were lower (P < 0.05) in older (34 +/- 2 ml.kg(-1).min(-1); 16.1 +/- 1.1 l/min) compared with young (43 +/- 3 ml.kg(-1).min(-1); 20.2 +/- 0.9 l/min) adults. Following ascorbic acid administration, neither Vo(2max) (young acute = 41 +/- 2; young chronic = 42 +/- 2; older acute = 34 +/- 2; older chronic = 34 +/- 2 ml.kg(-1).min(-1)) nor Q(max) (young acute = 20.1 +/- 0.9; young chronic = 19.1 +/- 0.8; older acute = 16.2 +/- 1.1; older chronic = 16.6 +/- 1.4 l/min) was changed. These data suggest that ascorbic acid administration does not affect the age-associated reduction in Q(max) and Vo(2max). PMID:15501926

  8. Evaluation of the Effects of Intravenous Ascorbic Acid on Correction of Anemia in Renal Failure Patients Undergoing Hemodialysis

    Directory of Open Access Journals (Sweden)

    AA Shojaie

    2006-04-01

    Full Text Available Introduction: Hemodialysis patients often develop resistance to recombinant human erythropoietin due to functional Iron Deficiency. In these patients iron therapy can be hazardous leading to hemosiderosis. Recent studies have suggested that intravenous ascorbic acid may be able to improve this hyporeponsiveness. The aim of this study was to evaluate the effect of intravenous ascorbic acid on functional iron deficiency and whether it results in better correction of anemia or not. Methods: Forty hemodialysis patients with serum ferritin >300ug/l, hemoglobin less than 10 gm/dl, and transferrin saturation less than 20% were selected. The reticulocyte index and KT/V was also calculated. Patients were later administered 500 mg intravenous ascorbic acid three times a week for three months. At the end of study, serum ferritin, transferrin saturation, hemoglobin, reticulocyte index and KT/V were rechecked and compared with the base line values by before and after method. Results: Serum ferritin decreased significantly (median base line ferritin 480.45 ug/dl as compared to final ferritin level of 363.78 (P=0.0001, whereas there was a significant rise in hemoglobin concentration (median baseline hemoglobin 8.92 gm/dl compared to 9.88gm/dl (P=0.0001. Transferrin saturation was also significantly raised (median baseline transferrin saturation 17.35% as compared to final level of 25.12% (P= 0.0001. KT/V before and after treatment with ascorbic acid had no significant change (P =0.396. Finally, the rate of decrease in serum ferritin and increase in hemoglobin according to age and duration of dialysis was studied. The effect of ascorbic acid was found to be significantly greater in older patients and those with longer duration of dialysis (P <0.05; but there was no significant relationship between transferrin saturation increase and age or duration of dialysis. Conclusion: Intravenous ascorbic acid may partially correct functional iron deficiency, although anemia is not totally corrected.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-01

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

  10. Sensitive and selective trypsin detection using redox cycling in the presence of L-ascorbic acid.

    Science.gov (United States)

    Park, Seonhwa; Yang, Haesik

    2014-08-21

    We report a simple, sensitive, and selective electrochemical method for trypsin detection that can cover a wide range of concentrations. The method is based on the proteolytic generation of an electroactive species (P) by trypsin followed by a signal-amplified electrochemical measurement of P using electrochemical-chemical (EC) or electrochemical-chemical-chemical (ECC) redox cycling. The detection is performed using bare indium-tin oxide (ITO) electrodes without washing steps. P is generated by the cleavage of an amide bond between P and oligopeptide (Gly-Pro-Arg) at the C-terminal of Gly-Pro-Arg-P. Four trypsin products including 4-amino-1-naphthol (AN) and their trypsin substrates are investigated to obtain a high signal-to-background ratio in ECC redox cycling. AN and its trypsin substrate produce the highest signal-to-background ratio. The detection limits obtained with ECC redox cycling involving AN (approximately 1 ng mL(-1) and 100 ng mL(-1) with an incubation period of 2 h and 30 min, respectively) in Tris buffer (pH 8.0) are lower than those obtained with EC redox cycling involving AN (approximately 5 ng mL(-1) and 200 ng mL(-1) with an incubation period of 2 h and 30 min, respectively). In trypsin detection using ECC redox cycling, the interference effects of electroactive species such as l-ascorbic acid and uric acid are not significant. PMID:24955437

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

    Scientific Electronic Library Online (English)

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

    2008-06-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-05-15

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

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

    International Nuclear Information System (INIS)

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

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

    Scientific Electronic Library Online (English)

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

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

  15. Growth and characterization of strontium oxalate crystals by the decomposition of ascorbic acid in presence of strontium chloride

    International Nuclear Information System (INIS)

    Full text: Ascorbic acid (vitamin c) is an important organic compound that helps to maintain the optimal health of human body. It is essential for the development and maintenance of connective tissues. Vitamin C plays an important role in a number of metabolic functions including the activation of the B vitamin, folic acid, the conversion of cholesterol to bile acids and the conversion of the amino acid, tryptophan, to the neurotransmitter, serotonin. During the process of metabolism it decomposes into oxalic acid. This compound is photosensitive and has least thermal stability. The decomposition of Ascorbic acid has been studied in various conditions. It is reported that decomposition of ascorbic acid in presence of Cd2+ ions leads to the formation of cadmium oxalate crystals. In the present work, in presence of Sr2+ ion the ascorbic acid is decomposed to Strontium Oxalate in gel media. In this technique, silica gel is used as a medium to grow crystals. Slow diffusion of reactants in the gel medium can be considered to mimic the growth of crystals in the human body. Gels were prepared by mixing appropriate quantities of sodium meta silicate and ascorbic acid, adjusting the pH in the range 5-7.5. Over the set gel, the feed solution of 1M Strontium chloride was added. Yellowish prismatic and bar shaped crystals were obtained within 24 hours. The nucleation density is maximum at a pH of 6 and minimum at 5. Good quality crystals were obtained for a Good quality crystals were obtained for a pH of 5 and gel density 1.05g/cc. The FTIR spectra of grown crystals are recorded and analyzed.The band at 3431 cm-1 is assigned to OH stretching frequency of co-ordinated water molecule and the band at 1637cm-1 corresponds to C=O Stretching of carbonyl group. The band at 1319cm-1 is assigned to symmetric stretching of COO- group. The IR band at 767cm-1 corresponds to the combined effect of inplane deformation of CO2 and the presence of metal oxygen bond .The band at 505cm-1 is due to wagging mode

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

    Directory of Open Access Journals (Sweden)

    Stefano Pontone

    2011-01-01

    Full Text Available 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, aged from 20 to 84 years (median age 59.5 years, who attended our Department, were divided into two groups, age and sex matched, and underwent colonoscopy. Two questionnaires, one for patients reporting acceptability and the other for endoscopists evaluating bowel cleansing effectiveness according to validated scales, were completed. Indications, timing of examination and endoscopical findings were recorded. Biopsy forceps were used as a measuring tool in order to determine polyp endoscopic size estimation. Difficulty in completing the preparation was rated in a 5-point Likert scale (1 = easy to 5 = unable. Adverse experiences (fullness, cramps, nausea, vomiting, abdominal pain, headache and insomnia, number of evacuations and types of activities performed during preparation (walking or resting in bed were also investigated. RESULTS: Seventy-two patients were selected for each group. The two groups were age and sex matched as well as being comparable in terms of medical history and drug therapies taken. Fourteen patients dropped out from the trial because they did not complete the preparation procedure. Ratings of global bowel cleansing examinations were considered to be adequate in 91% of PEG + Asc and 88% of PEG + Sim patients. Residual Stool Score indicated similar levels of amount and consistency of residual stool; there was a significant difference in the percentage of bowel wall visualization in favour of PEG + Sim patients. In the PEG + Sim group, 12 adenomas ? 10 mm diameter (5/left colon + 7/right colon vs 9 (8/left colon + 1/right colon in the PEG + Asc group were diagnosed. Visualization of small lesions seems to be one of the primary advantages of the PEG + Sim preparation. CONCLUSION: PEG + Asc is a good alternative solution as a bowel preparation but more improvements are necessary in order to achieve the target of a perfect preparation.

  17. Organic-inorganic hybrid materials based on polyaniline/TiO2 nanocomposites for ascorbic acid fuel cell systems

    International Nuclear Information System (INIS)

    Polyaniline was grafted onto a mixture of rutile and anatase TiO2 nanoparticles by in situ chemical oxidative polymerization. These nanocomposites were characterized by carbon, hydrogen and nitrogen (CHN) analysis, x-ray diffraction (XRD), Fourier transform infrared (FTIR), ultraviolet-visible (UV-vis), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. FTIR and UV-vis confirm the formation of polyaniline on TiO2 nanoparticles. The TEM shows that the composites consist of PANI and TiO2 nanoparticles. Compared to the neat polyaniline, PANI/TiO2 composites show a higher capacitance and also a higher activity per mass of polyaniline. Since the PANI/TiO2 composites are stable during the electrooxidation of ascorbic acid, they can be used as an alternative catalyst for direct ascorbic acid fuel cells.

  18. Organic inorganic hybrid materials based on polyaniline/TiO2 nanocomposites for ascorbic acid fuel cell systems

    Science.gov (United States)

    Ganesan, Raman; Gedanken, Aharon

    2008-10-01

    Polyaniline was grafted onto a mixture of rutile and anatase TiO2 nanoparticles by in situ chemical oxidative polymerization. These nanocomposites were characterized by carbon, hydrogen and nitrogen (CHN) analysis, x-ray diffraction (XRD), Fourier transform infrared (FTIR), ultraviolet-visible (UV-vis), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. FTIR and UV-vis confirm the formation of polyaniline on TiO2 nanoparticles. The TEM shows that the composites consist of PANI and TiO2 nanoparticles. Compared to the neat polyaniline, PANI/TiO2 composites show a higher capacitance and also a higher activity per mass of polyaniline. Since the PANI/TiO2 composites are stable during the electrooxidation of ascorbic acid, they can be used as an alternative catalyst for direct ascorbic acid fuel cells.

  19. Polyaniline film as a metal-free electrocatalyst for the anode reaction of the direct ascorbic acid fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Yano, J. [Nihama National College of Technology, Ehime (Japan). Dept. of Engineering Science; Hirayama, H.; Kitani, A. [Hiroshima Univ. (Japan). Faculty of Engineering

    2010-07-01

    This study investigated the use of a polyaniline (PANI) film as a metal-free electrocatalyst for the anode reaction of a direct ascorbic acid fuel cell. The PANI film acted as a porous support on which to disperse the electrocatalysts. The dispersion was used to decrease the poisoning effects of methanol byproducts as well as to preserve the amount of platinum (Pt) used in the electrocatalyst. The catalytic activities of the modified PANI electrodes were evaluated using linear sweep voltammetry and measurements of the current-time profile. Steady state polarization curves were used to estimate the durability of the catalytic action. Results of the study showed that the modified PANI film-modified electrode was highly active towards the electro-oxidation of L-ascorbic acid as well as being free from harmful heavy metals. 22 refs., 4 figs.

  20. Organic-inorganic hybrid materials based on polyaniline/TiO(2) nanocomposites for ascorbic acid fuel cell systems.

    Science.gov (United States)

    Ganesan, Raman; Gedanken, Aharon

    2008-10-29

    Polyaniline was grafted onto a mixture of rutile and anatase TiO(2) nanoparticles by in situ chemical oxidative polymerization. These nanocomposites were characterized by carbon, hydrogen and nitrogen (CHN) analysis, x-ray diffraction (XRD), Fourier transform infrared (FTIR), ultraviolet-visible (UV-vis), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. FTIR and UV-vis confirm the formation of polyaniline on TiO(2) nanoparticles. The TEM shows that the composites consist of PANI and TiO(2) nanoparticles. Compared to the neat polyaniline, PANI/TiO(2) composites show a higher capacitance and also a higher activity per mass of polyaniline. Since the PANI/TiO(2) composites are stable during the electrooxidation of ascorbic acid, they can be used as an alternative catalyst for direct ascorbic acid fuel cells. PMID:21832713

  1. Effect of high doses of L-ascorbic acid on the antioxidative/oxidative state in the rats

    DEFF Research Database (Denmark)

    Niemiec, T.; Sawosz, E.

    2005-01-01

    The objective of this study was to determine the effects of mega-doses of vitamin C (0.3, 0.6 and 0.9% of diet) as a dietary supplement for rats on selected indices of the antioxidative/oxidative state in 40 growing Wistar rats (4x10). It was found that L-ascorbic acid and Total Antioxidative State (TAS) in plasma did not increase with increasing vitamin C supply. The results indicate that high doses of L-ascorbic acid (0.3 and 0.9 but not 0.6%) increased the concentration of this antioxidant in plasma. Supplementation of vitamin C above 0.3% to the diets had pro-oxidative effects on lipid structures, while application of 0.9% promoted oxidative degradation of rat livers.

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

    Directory of Open Access Journals (Sweden)

    Marli Aparecida Dos Santos Pereira

    2006-08-01

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

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

    Scientific Electronic Library Online (English)

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

    2006-08-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-05

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Sushil Kumar

    2012-05-01

    Full Text Available Multiwalled carbon nanotubes were used to modify the surface of a glassy carbon electrode to enhance its electroactivity. Nafion served to immobilise the carbon nanotubes on the electrode surface. The modified electrode was used to develop an analytical method for the analysis of ascorbic acid (AA by square-wave voltammetry (SWV. The oxidation of ascorbic acid at the modified glassy carbon electrode showed a peak potential at 315 mV, about 80 mV lower than that observed at the bare (unmodified electrode. The peak current was about threefold higher than the response at the bare electrode. Replicate measurements of peak currents showed good precision (3% rsd. Peak currents increased with increasing ascorbic acid concentration (dynamic range = 0.0047–5.0 mmol/L and displayed good linearity (R2 = 0.994. The limit of detection was 1.4 ?mol/L AA, while the limit of quantitation was 4.7 ?mol/L AA. The modified electrode was applied to the determination of the amount of ascorbic acid in four brands of commercial orange-juice products. The measured content agreed well (96–104% with the product label claim for all brands tested. Recovery tests on spiked samples of orange juice showed good recovery (99–104%. The reliability of the SWV method was validated by conducting parallel experiments based on high-performance liquid chromatography (HPLC with absorbance detection. The observed mean AA contents of the commercial orange juice samples obtained by the two methods were compared statistically and were found to have no significant difference (P = 0.05.

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

    OpenAIRE

    Kishna Ram Genwa; Kewal Singh

    2013-01-01

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

  10. Plasma levels and redox status of ascorbic acid and levels of lipid peroxidation products in active and passive smokers.

    OpenAIRE

    Ayaori, M.; Hisada, T.; Suzukawa, M.; Yoshida, H.; Nishiwaki, M.; Ito, T.; Nakajima, K.; Higashi, K.; Yonemura, A.; Ohsuzu, F.; Ishikawa, T.; Nakamura, H.

    2000-01-01

    Both active and passive smoking are regarded as risk factors for various diseases. To clarify the effects of active and passive smoking on plasma vitamin C levels and lipid peroxidation status, we examined the plasma levels of ascorbic acid (AA), its redox status [ratio of dehydroascorbate (DHAA) to total AA], the levels of thiobarbiturate reactive substance (TBARS), and the levels of lipid peroxides (LPO) in smokers, nonsmokers, and nonsmokers regularly exposed to environmental cigarette smo...

  11. Ascorbic Acid Enhances the Accumulation of Polycyclic Aromatic Hydrocarbons (PAHs) in Roots of Tall Fescue (Festuca arundinacea Schreb.)

    OpenAIRE

    Gao, Yanzheng; Li, Hui; Gong, Shuaishuai

    2012-01-01

    Plant contamination by polycyclic aromatic hydrocarbons (PAHs) is crucial to food safety and human health. Enzyme inhibitors are commonly utilized in agriculture to control plant metabolism of organic components. This study revealed that the enzyme inhibitor ascorbic acid (AA) significantly reduced the activities of peroxidase (POD) and polyphenol oxidase (PPO), thus enhancing the potential risks of PAH contamination in tall fescue (Festuca arundinacea Schreb.). POD and PPO enzymes in vitro e...

  12. Ascorbic Acid and a Cytostatic Inhibitor of Glycolysis Synergistically Induce Apoptosis in Non-Small Cell Lung Cancer Cells

    OpenAIRE

    Vuyyuri, Saleha B.; Rinkinen, Jacob; Worden, Erin; Shim, Hyekyung; Lee, Sukchan; Davis, Keith R.

    2013-01-01

    Ascorbic acid (AA) exhibits significant anticancer activity at pharmacologic doses achievable by parenteral administration that have minimal effects on normal cells. Thus, AA has potential uses as a chemotherapeutic agent alone or in combination with other therapeutics that specifically target cancer-cell metabolism. We compared the effects of AA and combinations of AA with the glycolysis inhibitor 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3-PO) on the viability of three non-small cell ...

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

    OpenAIRE

    Cc, Lima; Apc, Pereira; Jrf, Silva; Ls, Oliveira; Mcc, Resck; Co, Grechi; Mtcp, Bernardes; Fmp, Oli?mpio; Amm, Santos; Ek, Incerpi; Jad, Garcia

    2009-01-01

    BACKGROUND: Healing is a complex process that involves cellular and biochemical events. Several medicines have been used in order to shorten healing time and avoid aesthetic damage. OBJECTIVE: to verify the topical effect of ascorbic acid for the healing of rats' skin wounds through the number of macrophages, new vessels and fibroblast verifications in the experimental period; and analyse the thickness and the collagen fibre organization in the injured tissue. METHODS: Male Rattus norvegicus ...

  14. Microdialytical monitoring of uric and ascorbic acids in the brains of patients after severe brain injury and during neurovascular surgery

    OpenAIRE

    Langemann, H.; Feuerstein, T.; Mendelowitsch, A.; Gratzl, O.

    2001-01-01

    OBJECTIVES—Microdialysis has been extensively used to monitor brain metabolism in the extracellular fluid of patients with severe head injury, to detect the onset of secondary ischaemic damage. The aim was to investigate whether concentrations of uric and ascorbic acids were altered in such patients. Both these compounds play a part in free radical metabolism, which is accelerated after ischaemia and brain injury.?METHODS—Patients with aneurysm or bypass operatio...

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

    OpenAIRE

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

    2013-01-01

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

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

    OpenAIRE

    Mohammad Amani; Ali Noroozzadeh; Reza Badalzadeh; Ali Khoshbaten

    2010-01-01

    Background: Extended exposure to low levels of lead causes high blood pressure in human and laboratory animals. The mechanism is not completely recognized, but it is relatively implicated with generation of free radicals, oxidant agents such as ROS, and decrease of available nitric oxide (NO). In this study, we have demonstrated the effect of ascorbic acid as an antioxidant on nitric oxide metabolites and systolic blood pressure in rats exposed to low levels of lead. Materials and Methods:...

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

    Directory of Open Access Journals (Sweden)

    A. M. Hamada

    2000-01-01

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

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

    OpenAIRE

    Jianqing Zhou; Meili Sheng; Xueyue Jiang; Guozhi Wu; Feng Gao

    2013-01-01

    A novel glassy carbon electrode (GCE) modified with carbon-spheres has been fabricated through a simple casting procedure. The modified GCE displays high selectivity and excellent electrochemical catalytic activities towards dopamine (DA), serotonin (5-HT), and ascorbic acid (AA). In the co-existence system, the peak separations between AA and DA, DA and 5-HT, and AA and 5-HT are large up to 230, 180, and 410 mV, respectively. Differential pulse voltammetry (DPV) has been employed to simultan...

  19. Selective Determination of Epinephrine in the Presence of Ascorbic Acid and Dopamine Using a Glassy Carbon Electrode Modified with Valine

    OpenAIRE

    Xia Li; Meifeng Chen; Xinying Ma; Xianjie Lin

    2010-01-01

    A glassy carbon electrode (GCE) modified with valine was used for the sensitive volt metric determination ofepinephrine (EP). The electrochemical response characteristics of the modified electrode toward EP, ascorbic acid (AA)and dopamine (DA) were investigated by cyclic voltammetry (CV). The results show an efficient catalytic activity ofthe electrode for the electro-oxidation of EP, which leads to an improvement to the reversibility of the electroderesponse. The effect of pH and potential s...

  20. Simultaneous Determination of Dopamine and L-Ascorbic Acid by Modified Carbon Paste Electrode with Ni (II) Cyclam Complex

    OpenAIRE

    Mohammad Reza Milani Hosseini; Leila Farzin

    2011-01-01

    The electroanalysis of dopamine (DA) and ascorbic acid (AA) by square wave voltammetry has been performed at a modified carbon paste electrode with macrocyclic ligand 1, 4, 8, 11-tetraazacyclotetradecane (cyclam) and monolayer of Ni (II) cyclam. In pH 7.2 buffer solutions, the electrostatic reaction of AA with di-positive monolayer shifts the oxidation potential to less positive potential, while the electrostatic repulsion of DA with the monolayer shifts the oxidation potential of DA to more ...

  1. The Effect of Glycinebetaine or Ascorbic Acid on the Salt-Stress Induced Damages in Sorghum Plant Cells

    OpenAIRE

    Arafa, A. A.; Khafagy, M. A.; El-banna, M. F.

    2007-01-01

    The effects of exogenously applied glycinebetaine or ascorbic acid (pre-soaking or pre-soaking plus spraying) on the salt-stress induced ultrastructural damages in sorghum seedlings were investigated. The seedlings grown in hydroponic culture containing nutrient solution for 3 weeks treated with NaCl at (0 and 6000 ppm). Salinity induced ultrastructural damages in leaf such as swelling of thylakoids, disintegration of grana stacking and intergrana lamellae, an increase in the number of plasto...

  2. Protective Effects of Extract from Dates (Phoenix Dactylifera L.) and Ascorbic Acid on Thioacetamide-Induced Hepatotoxicity in Rats

    OpenAIRE

    Mohamed Bastway Ahmed; Nabil Abdel-Salam Hasona; Hanan Abdel-Hamid Selemain

    2008-01-01

    The ameliorative activity of aqueous extract of the flesh of dates (Phoenix dactylifera L.) and ascorbic acid on thioacetamide-induced hepatotoxicity was studied in rats. Sixty male rats were divided into six equal groups of 10. Two groups were controls, one treated with thioacetamide and one with only distilled water. Two groups received extract of flesh Phoenix dactylifera and intraperitoneal (IP) thioacetamide (400 mg/kg) either before or after administration of flesh extract. Two groups r...

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

    OpenAIRE

    Ghazi, F; M. Firoozrai; B. Dabirmanesh; Shabani, A.

    2009-01-01

    Angiotensin-Converting Enzyme (ACE) is a dipeptidyl carboxypeptidase (EC: 3.4.15.1) that catalyzes the conversion of angiotensin I to the potent vasoconstrictor angiotensin II. Angiotesin II is responsible for an increase in blood pressure and maintenance of hypertension through the stimulation of oxidative stress. The relationship between Coronary Artery Disease (CAD), Angiotensin-Converting Enzyme (ACE) activity, ascorbic acid and serum antioxidant status in patients with coronary artery di...

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

    OpenAIRE

    Andreea BRASOVAN; Vlad CODREA; Vasilica MÂNDROC; Ramona CÂMPEAN; Neli OLAH

    2009-01-01

    The study presents data on content determination of calcium, magnesium and ascorbic acid in sea buckthorn fruits collected from Vulcan coal dump. The dump was never covered with soil or fertilizers containing azoth, potassium and phosphorus. The sea buckthorn was planted directly on the sterile and it has an important function in stabilizing the acclivity and fixing the atmospheric azoth with the nodosities on the roots. So, the sea buckthorn becomes widespread plant in coal dumps because it ...

  5. Effect of Ascorbic Acid Foliar Application on Yield, Yield Component and several Morphological Traits of Grain Corn under Water Deficit Stress Conditions

    Directory of Open Access Journals (Sweden)

    Aria DOLATABADIAN

    2010-09-01

    Full Text Available In order to study effect of ascorbic acid foliar application on morphological traits, yield and yield components of grain corn under conditions of water stress, an experiment was conducted in Tarbiat Modares University, Tehran, Iran in 2006 growing season. Experimental design was RCBD (Randomized Complete Block Design and treatments were sat in split-split plot arrangement. Water deficit stress treatment with three levels (no stress, vegetative phase stress and reproductive phase stress was allocated to main plots. Ascorbic acid was used at two time (vegetative phase and reproductive phase and four concentration (0, 50, 100 and 150 mgl-1 as sub plots and sub-sub plots, respectively. The results demonstrated that water deficit stress and ascorbic acid foliar application had significant effect on upon traits. Water deficit stress significantly decreased dry or fresh weight of plants at two growing phases, but leaf area was just decreased due to water deficit stress at vegetative phase. Regarding yield and yield components, a significant decrease was observed when plants were water stressed. It?s notable that final yield was more affected when plants were stressed at reproductive phase than those were stressed at vegetative phase. Ascorbic acid foliar application increased stem and leaf dry weight and leaf fresh weight. In addition, an increase was observed in grain weight when plants were treated by 150 mgl-1 ascorbic acid at two growing phases and no stress and vegetative stress. The highest infertile grains were observed in reproductive stress and without ascorbic acid plots while ascorbic acid foliar application led to increase of grain fertility. In general, these results suggests that ascorbic acid foliar application decreases adverse effects of water deficit stress and improves growth and production at normal and stressed conditions.

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

    Scientific Electronic Library Online (English)

    I.L, MATTOS; F, PADILLA; J. H, ZAGAL; E.H.L, FALCAO; R, SEGURA.

    Full Text Available A flow injection system using a new and/or re-used graphite screen-printed electrode modified with silver hexacyanoferrate and a Nafion® polymer layer (AgHCF/GSPE) was employed for the determination of ascorbic acid in orange juice and drugs samples. Both modified electrodes showed an initial sensit [...] ivity of 0.015 A.cm²?.M¹?, with a linear response over the range from 50 to 300 mg L¹ , relative standard deviations smaller than 2%, detection and quantification limits of c.a. 5.0 and 25.0 mg.L¹. The response of the electrodes was stable, with no variation of base line after 6-8 hours of continuous operation. With this system it is possible to measure 65-70 samples (20??) per hour. By using 1.06 mg of AgNO3, 4.12 mg of K3Fe(CN)6, 50.5 mg of KNO3 and 800?L of HNO3, it is possible to obtain between 25 and 30 modified electrodes. The proposed system showed to be inexpensive, versatile, robust and suitable for industrial application. The surface morphology of the bare and/or modified graphite screen-printed electrode was characterized by scanning electron microscopy.

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

    Directory of Open Access Journals (Sweden)

    I.L MATTOS

    2011-01-01

    Full Text Available A flow injection system using a new and/or re-used graphite screen-printed electrode modified with silver hexacyanoferrate and a Nafion® polymer layer (AgHCF/GSPE was employed for the determination of ascorbic acid in orange juice and drugs samples. Both modified electrodes showed an initial sensitivity of 0.015 A.cm²?.M¹?, with a linear response over the range from 50 to 300 mg L¹ , relative standard deviations smaller than 2%, detection and quantification limits of c.a. 5.0 and 25.0 mg.L¹. The response of the electrodes was stable, with no variation of base line after 6-8 hours of continuous operation. With this system it is possible to measure 65-70 samples (20?? per hour. By using 1.06 mg of AgNO3, 4.12 mg of K3Fe(CN6, 50.5 mg of KNO3 and 800?L of HNO3, it is possible to obtain between 25 and 30 modified electrodes. The proposed system showed to be inexpensive, versatile, robust and suitable for industrial application. The surface morphology of the bare and/or modified graphite screen-printed electrode was characterized by scanning electron microscopy.

  8. [Effect of ascorbic acid (vitamin C) on the EPR spectra from the black and red hair].

    Science.gov (United States)

    Chikvaidze, E; Miminoshvili, A; Gogoladze, T; Kiparoidze, S

    2012-02-01

    The EPR spectra of melanin's free radicals in natural black and red hair have been investigated. It is show that the EPR spectrum of black hair is slightly asymmetric singlet with g=2,0035 and ?H=0,5 mTl. The EPR spectrum of red hair with g=2,0053 differs from the spectrum of black hair. Under the influence of visible (blue with ?(max)=450 nm) in both types of hair (black and red), the protoinduced free radicals appear, which indicates an increase in the intensity of already existing EPR spectrum of hair. It should be noted that the EPR spectra of red hair from various donors are different. The antioxidant ascorbic acid has the different effect on the photoinduced free radicals. In particular, in the case of black hair, the concentration of photoinduced free radicals is slightly reduced, whereas in red hair, the disappearance of the triplet in the spectrum is observed, and at the same time, the spectrum becomes a singlet, the intensity of which increases sharply. PMID:22466543

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

    DEFF Research Database (Denmark)

    Kjær Nielsen, Torben; HØjgaard, Martin

    2015-01-01

    Treatment with high-dose intravenous (IV) ascorbic acid (AA) is used in complementary and alternative medicine for various conditions including cancer. Cytotoxicity to cancer cell lines has been observed with millimolar concentrations of AA. Little is known about the pharmacokinetics of high dose IV AA. The purpose of the present study was to assess the basic kinetic variables in human beings over a relevant AA dosing interval for proper design of future clinical trials. Ten patients with metastatic prostate cancer were treated for four weeks with fixed AA doses of 5, 30 and 60 g. AA was measured consecutively in plasma and indicated first-order elimination kinetics throughout the dosing range with supra-physiological concentrations. The target dose of 60g AA IV produced a peak plasma AA concentration of 20.3 mM. Elimination half-life was 1.87 hr (mean, SD ± 0.40), volume of distribution 0.19 L/kg (SD ±0.05) and clearance rate 6.02 L/hr (100mL/min). No differences in pharmacokinetic parameters were observed between weeks/doses. A relatively fast first-order elimination with half-life of about 2 hr makes it impossible to maintain AA concentrations in the potential cytotoxic range after infusion stop in prostate cancer patients with normal kidney function. We propose a regimen with a bolus loading followed by a maintenance infusion based on the calculated clearance. This article is protected by copyright. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Ciprian Radovan

    2008-06-01

    Full Text Available Cyclic voltammetry (CV and chronoamperometry (CA have been used to sense and determine simultaneously L-ascorbic acid (AA and acetaminophen (AC at a boron-doped diamond electrode (BDDE in a Britton-Robinson buffer solution. The calibration plots of anodic current peak versus concentration obtained from CV and CA data for both investigated compounds in single and di-component solutions over the concentration range 0.01 mM – 0.1 mM proved to be linear, with very good correlation parameters. Sensitivity values and RSD of 2-3% were obtained for various situations, involving both individual and simultaneous presence of AA and AC. The chronoamperometric technique associated with standard addition in sequential one step and/or two successive and continuous chronoamperograms at two characteristic potential levels represented a feasible option for the simultaneous determination of AA and AC in real sample systems such as pharmaceutical formulations. The average values indicated by the supplier were confirmed to a very close approximation from chronoamperomgrams by using several additions with the application of suitable current correction factors.

  11. Electrocatalytic oxidation of ascorbic acid on a lithium-doped tantalum oxide film coated electrode

    International Nuclear Information System (INIS)

    In this work, lithium-doped tantalum oxide (lithium-Ta2O5) particles were synthesized using a low-temperature hydrothermal method. X-ray photoelectron spectroscopy (XPS) indicated that the state of lithium on the Ta2O5 surface is the Li+ form. The crystal phase of the samples was analyzed using X-ray diffraction (XRD). The analysis revealed that the lithium-Ta2O5 particles are well crystallized into an orthorhombic phase. Calculation from density functional theory (DFT) indicated that the band gap of Ta2O5 narrows when it is doped with lithium, resulting in improved conductivity and electrocatalytic activity over Ta2O5. The electrocatalytic activity of a lithium-Ta2O5 film coated electrode was investigated in a 0.1 mol dm?3 KCl solution containing ascorbic acid (AA) using cyclic voltammetry (CV). The lithium-Ta2O5 film coated electrode has excellent electrocatalytic activity toward the oxidation of AA with much reduced overpotential. The anodic peak potential of AA shifted from 0.72 V (versus Ag|AgCl) on a bare glassy carbon electrode (GCE) to 0.42 V on the lithium-Ta2O5 film coated electrode

  12. Elimination of ascorbic acid after high-dose infusion in prostate cancer patients : a pharmacokinetic evaluation

    DEFF Research Database (Denmark)

    Nielsen, Torben Kjær; HØjgaard, Martin

    2015-01-01

    Treatment with high-dose intravenous (IV) ascorbic acid (AA) is used in complementary and alternative medicine for various conditions including cancer. Cytotoxicity to cancer cell lines has been observed with millimolar concentrations of AA. Little is known about the pharmacokinetics of high dose IV AA. The purpose of the present study was to assess the basic kinetic variables in human beings over a relevant AA dosing interval for proper design of future clinical trials. Ten patients with metastatic prostate cancer were treated for four weeks with fixed AA doses of 5, 30 and 60 g. AA was measured consecutively in plasma and indicated first-order elimination kinetics throughout the dosing range with supra-physiological concentrations. The target dose of 60g AA IV produced a peak plasma AA concentration of 20.3 mM. Elimination half-life was 1.87 hr (mean, SD ± 0.40), volume of distribution 0.19 L/kg (SD ±0.05) and clearance rate 6.02 L/hr (100mL/min). No differences in pharmacokinetic parameters were observed between weeks/doses. A relatively fast first-order elimination with half-life of about 2 hr makes it impossible to maintain AA concentrations in the potential cytotoxic range after infusion stop in prostate cancer patients with normal kidney function. We propose a regimen with a bolus loading followed by a maintenance infusion based on the calculated clearance. This article is protected by copyright. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Hassan Bayat

    2013-08-01

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

  14. Optical paper-based sensor for ascorbic acid quantification using silver nanoparticles.

    Science.gov (United States)

    Ferreira, Danielle Cristhina Melo; Giordano, Gabriela Furlan; Soares, Caio César Dos Santos Penteado; de Oliveira, Jessica Fernanda Afonso; Mendes, Renata Kelly; Piazzetta, Maria Helena; Gobbi, Angelo Luiz; Cardoso, Mateus Borba

    2015-08-15

    In this paper, we demonstrate for the first time the use of silver nanoparticles (AgNPs) for colorimetric ascorbic acid (AA) quantification in a paper-based sensor. This device is constituted by spot tests modified with AgNPs and silver ions bordered by a hydrophobic barrier which provides quantitative and fast analysis of AA. In addition, this device is employed as point-of-care monitoring using a unique drop of the sample. AgNPs paper-based sensor changed from light yellow to gray color after the addition of AA due to nanoparticle growth and clusters formation. The color intensities were altered as a function of AA concentration which were measured by either a scanner or a homemade portable transmittance colorimeter. Under the selected measurement conditions, results presented limit of detection which was comparable to analytical laboratory-based methodologies. In addition, the sensitivity of our sensor was comparable to the standard titration method when real samples were investigated. PMID:25966401

  15. Uptake and release of adrenal ascorbic acid in the guinea pig after injection of ACTH

    International Nuclear Information System (INIS)

    The effect of a single injection of ACTH (3 IU/100 g body weight) on the distribution of ascorbic acid (AA) and radiolabeled AA in 20 tissues was studied in adult male guinea pigs consuming 500 mg AA/kg diet. Saline- or ACTH-injected animals were simultaneously injected with [1-14C]AA, and killed at 0.5, 1, 2, 4 and 6 h after injection. There was no significant difference between treatments in the weight of any tissue over the 6-h experimental period. As anticipated, the concentration of AA in the adrenals of animals injected with ACTH was 33% of that of animals injected with saline at 4 h. Unexpectedly, the concentration of radiolabeled AA in the adrenals at 0.5 h after ACTH injection was 172% of that after saline injection. The concentration of radiolabeled AA in the adrenal of the saline-injected animals increased slowly over time to reach a level similar to that of ACTH-injected animals by 6 h. There was no effect of ACTH on the level of AA or uptake in any of the other tissues examined. These results demonstrate that a single dose of ACTH markedly influences the retention of AA in the adrenal gland without similarly altering retention of AA in other tissues. Furthermore, ACTH treatment causes both accelerated uptake and release of AA into the adrenals

  16. Effects of Socio demographic factors on plasma ascorbic acid and alpha tocopherol anti oxidants during pregnancy

    International Nuclear Information System (INIS)

    Objectives: To assess the plasma levels of vitamins C and E at the various stages of pregnancy and to correlate their plasma levels with the socio-demographic factors of pregnant Nigerians. Methodology: The pregnant cases (n=180) were randomly selected according to gestational ages. And the controls (n=20) were non-pregnant women of the same age. Plasma levels of both vitamins were assayed with well established laboratory methods. Results: The mean plasma vitamins C and E in the pregnant cases was lower (by 17-23%) than controls across the three trimesters, p<0.0001. The correlation of vitamin C versus maternal age was significant; r = - 0.59, p<0.05; the mean plasma level of vitamin C declined by 57% as the maternal age increases from 22-37 years. Conclusion: The mean plasma Ascorbic acid and Alpha-tocopherol are reduced during pregnancy and socio-demographic factors have mild effects on the plasma levels of these vitamins. (author)

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

    Science.gov (United States)

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

    2014-12-01

    In this work, we present a novel ascorbic acid (AA) sensor applied to the detection of AA in human sera and pharmaceuticals. A series of Au nanoparticles (NPs) and graphene oxide sheets (Au NP/GO) composites were successfully synthesized by reduction of gold (III) using sodium citrate. Then the Au NP/GO composites were used to construct nonenzymatic electrodes in practical AA measurement. The electrode that has the best performance presents attractive analytical features, such as a low working potential of +0.15 V, a high sensitivity of 101.86 ?A mM-1 cm-2 to AA, a low detection limit of 100 nM, good reproducibility and excellent selectivity. And more,it was also employed to accurately and practically detect AA in human serum and clinical vitamin C tablet with the existence of some food additive. The enhanced AA electrochemical properties of the Au NP/GO modified electrode in our work can be attributed to the improvement of electroactive surface area of Au NPs and the synergistic effect from the combination of Au NPs and GO sheets. This work shows that the Au NP/GO/GCEs hold the prospect for sensitive and selective determination of AA in practical clinical application.

  18. Determination of uric acid in human urine by eliminating ascorbic acid interference on copper(II)-polydopamine immobilized electrode surface

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • A simple strategy for preparation of ploydopamine-Cu(II) coating on electrode. • The sensor shows the extraordinary selectivity for electrochemical determination of UA. • Modified electrode was characterized in detail. • Practical application was demonstrated in urine samples. - Abstract: The polydopamine (PD) coating was spontaneously formed through simple immersion of glassy carbon (GC) electrode in a dilute aqueous solution of dopamine (DA) at acidic solution (pH = 4.5) in the presence of Cu2+. Copper(II) ions were anchored on surface of GC electrode to prepare a PD-Cu(II) modified electrode. The morphology, composition and electrochemical properties of the PD-Cu(II) films were characterized by scanning electron microscopy, energy-dispersive spectrometry, X-ray photoelectron spectroscopy, powder X-ray diffraction, electrochemical impedance spectroscopy and cyclic voltammetry. This modified electrode shows the extraordinary selectivity for electrochemical determination of uric acid (UA) without interference of high concentration of ascorbic acid (AA). Under coexistence of 5 mM AA, the differential pulse voltammetry peak current of UA give linear response over the range of 0.06–1.68 mM (R2= 0.9934) with detection limit of 24.6 ?M (S/N = 3). Furthermore, the proposed sensor is ideal for the analysis of UA in human urine samples providing satisfactory results

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

    Science.gov (United States)

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

    2014-03-01

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

  20. Efficient DNA Cleavage Induced by RhIII(TMPyP5+ in the Presence of Ascorbic Acid

    Directory of Open Access Journals (Sweden)

    Nanda Gunawardhana

    2012-05-01

    Full Text Available The ability of Rh(III tetrakis-N-methylpyridyl porphyrin, RhIII(TMPyP5+, to interact with and cleave DNA was, investigated by UV-visible, luminescence, circular dichroism (CD, electron spin resonance (ESR and gel electrophoresis methods in the presence or absence of ascorbic acid. UV-absorption data showed that RhIII(TMPyP5+ is capable of interacting with DNA, as indicated by the appearance of a red shift and hypochromicity of the Soret band. The CD data revealed that RhIII(TMPyP5+ was capable of binding to DNA via an external binding mode. The RhIII(TMPyP5+ showed fluorescence and phosphorescence at room temperature. The phosphorescence increased in the presence of DNA and this could be attributed to the shielding of the metal-porphyrin by DNA. Gel electrophoresis studies revealed that RhIII(TMPyP5+ was only able to cleave DNA in the presence of the reducing agent  ascorbic acid. ESR data indicated the formation of RhII(TMPyP5+ by reduction of RhIII(TMPyP5+ with ascorbic acid. The involvement of Rh(III/Rh(II species in catalytic DNA cleavage and a possible DNA cleavage mechanism is discussed.

  1. Influence of dried Hokkaido pumpkin and ascorbic acid addition on chemical properties and colour of corn extrudates.

    Science.gov (United States)

    Obradovi?, Valentina; Babi?, Jurislav; Šubari?, Drago; Jozinovi?, Antun; A?kar, ?ur?ica; Klari?, Ilija

    2015-09-15

    The influence of Hokkaido pumpkin powder (PP) addition to corn grits at levels 4%, 6%, and 8% and ascorbic acid (AA) addition at levels 0.5% and 1% was evaluated. Extrusion was done using a single-screw extruder at two temperature regimes: 135/170/170°C (E1) and 100/150/150°C (E2). Mathematical models that describe the influence of additives on the colour of extrudates were determined. Raw extrusion mixtures as well as obtained extrudates were tested for ascorbic acid, polyphenol, proteins, fat, crude fibre, ash and carotenoids content, and antioxidant activity. E1 extrusion regime acted favourably on polyphenols, crude fibre content, and antioxidant activity. It also caused higher fat degradation than E2 extrusion. Xanthophylls (lutein and zeaxanthin) were less sensitive to extrusion than carotenes (?-carotene, 9-cis-?-carotene and 13-cis-?-carotene). Ascorbic acid was more sensitive to higher extrusion temperatures (49-76% degradation). It provided protection to carotenoids and consequently the colour of the extrudates. PMID:25863621

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

    Directory of Open Access Journals (Sweden)

    Fernandes Julio Cesar B.

    2000-01-01

    Full Text Available A flow injection system using a tubular electrode based on the redox properties of copper (II ions occluded in EVA membrane was developed for L-ascorbic acid determination. The poly-ethylene-co-vinyl acetate (EVA 40% m/m matrix was doped with copper (II ions and dispersed on the surface of a graphite/epoxy tubular electrode. The electrode showed a super-Nernstian response for L-ascorbic acid concentration between 10-3 and 10-1 mol L-1 with a detection limit of 8.5×10-4 mol L-1, when 0.1 mol L-1 KH2PO4 buffer mixed with 0.1 mol L-1 hydrogen peroxide at pH 5.0 was employed as carrier. The Potentiometric-FIA system allows an analytical frequency of 120 samples per hour with a precision of 3.6%. The results obtained for ascorbic acid determination in pharmaceutical samples, without any previous treatment, were similar to those obtained by the British Pharmacopoeia method.

  3. Effects of ascorbic acid and alpha tocopherol supplementation on basal testosterone cortisol ratio in male sprague dawley rats

    International Nuclear Information System (INIS)

    Background: Basal testosterone cortisol ratio is considered very important to maintain homeostasis. Increase in this ratio has various beneficial effects on body. In this study we determined the effects of ascorbic acid and alpha tocopherol supplementation on basal testosterone cortisol ratio in male Sprague Dawley rats. Methods: It was quasi experimental study carried out in department of Physiology, Army Medical College Rawalpindi in collaboration with National Institute of Health, Islamabad during October 2006 to September 2007. Forty male Sprague Dawley rats were divided into four groups with ten rats in each group and above mentioned antioxidants supplementation were given along with standard diet for one month. After this, blood samples were taken and analyzed for serum testosterone and cortisol by ELISA and malondialdehyde levels colorimetrically. Data were analysed on SPSS version 13 and p<0.05 was considered significant. Results: There was no significant rise in testosterone cortisol ratio in rats supplemented with single antioxidant; however rats supplemented with combination of ascorbic acid and alpha tocopherol revealed significant rise in testosterone cortisol ratio with a fall in malondialdehyde levels. Conclusions: Synergistic effects of ascorbic acid and alpha tocopherol resulted in a decline in reactive oxygen species induced lipid peroxidation and rise of testosterone cortisol ratio. (author)

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

    International Nuclear Information System (INIS)

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

  5. Antioxidant activity of ascorbic acid against peroxidation of phosphatidylcholine liposomes exposed to gamma radiation: a synergistic interaction?

    International Nuclear Information System (INIS)

    Ionizing radiation induced damage of cellular membrane is known to alter many structural and physiological processes leading to the loss of the normal cellular function including cell death. The present study was designed to determine the changes in bilayer permeability in egg lecithin multilamellar vesicles after exposure to gamma-radiation at doses of 500 Gy and 1 kGy. Liposomal changes in permeability were monitored by measuring the leakage of pre-encapsulated 6-carboxyfluorescein (CF). The changes in permeability in the bilayer were found to be dependent on radiation dose. The presence of hydrophilic antioxidant ascorbic acid (0.1 mM) in the aqueous medium drastically increased the leakage of carboxyfluorescein from liposomes. IR and NMR studies which have been employed to reveal structural alterations in irradiated vesicles showed an increased damage upon exposure to radiation in the presence of ascorbic acid. The proton nuclear magnetic resonance (1H NMR) spectrum of the irradiated lipid vesicles (in the presence of ascorbic acid) showed a preponderance of signals attributable to new compounds formed as a consequence of the degradation process. The obtained results contribute to our understanding of the mechanism of radiation oxidative damage and its modification by radical scavenging and/or organizational modulation, which emphasize the importance of structure and composition of antioxidant in developing new strategies to reduce the damaging effects strategies to reduce the damaging effects of ionizing radiation. (author)

  6. Effect of Ascorbic Acid (Vitamin C Leaf Feeding on Antioxidant Enzymes Activity, Proline Accumulation and Lipid Peroxidation of Canola (Brassica napus L. under Salt Stress Condition

    Directory of Open Access Journals (Sweden)

    A Modares Sanavi

    2009-04-01

    Full Text Available In order to study the effects of salt stress and leaf feeding by ascorbic acid on antioxidant enzyme activity, proline accumulation and lipid peroxidation on leaves and roots of Brassica napus L. cvs. Okapi, an experiment was conducted as a factorial in a completely random design with three replications. Plants were exposed to salt stresses by NaCl solution (200 mM and foliar were treated by ascorbic acid solution (25mM. Catalase, Superoxide dismutase and peroxidase activity were assayed in shoot and root. Also, malondialdehyde content and proline and chlorophyll in leaves were determined. The results showed that the activity of all antioxidant enzymes (except for SOD in roots were increased significantly in plants under salt stress, and ascorbic acid application, as a antioxidant decreased their activity in leaves, but in roots it was not effective. Total protein content in leaves and roots decreased significantly under salinity condition. Ascorbic acid treatment increased total protein content under salt stress in both roots and shoots. Measurement of malondialdehyde content in leaves and roots showed that lipid peroxidation was increased by active oxygen species due to salt stress, and ascorbic acid reduced lipid peroxidation only in leaves. Chlorophyll content was also decreased by salinity compared to control. According to the result of present study, ascorbic acid application decreases deleterious effect of salinity.

  7. Effect of the Ascorbic Acid, Pyridoxine and Hydrogen Peroxide Treatments on Germination, Catalase Activity, Protein and Malondialdehyde Content of Three Oil Seeds

    Directory of Open Access Journals (Sweden)

    Seyed Ali Mohammad MODARRES SANAVY

    2008-08-01

    Full Text Available Oil seed production has an important role in human nutrition and industry. Success in oil plant cultivation is related to seed production with high viability and rapid germination, because these seeds rapidly loose their viability by fats oxidation. Thus, in this work we studied the effects of ascorbic acid, pyridoxine and hydrogen peroxide solutions on germination quantitative traits, catalase activity, protein and malondialdehyde content of three old oil seeds (sunflower, rape seed and safflower. The results showed that ascorbic acid and pyridoxine stimulated significantly the sunflower and rape seed germination. These vitamins, however, didn't have any effect on safflower germination. Hydrogen peroxide strongly increased safflower germination. Ascorbic acid and pyridoxine decreased catalase activity in sunflower and rape seed, whereas hydrogen peroxide increased it. Ascorbic acid and pyridoxine prevented protein degradation and lipid peroxidation in germinated seeds. Consequently, we understand that ascorbic acid and pyridoxine can increase sunflower and rape seed germination and stimulate rate of growth. Also safflower germination increased due to germination inhibitor oxidation by hydrogen peroxide. In conclusion, this report shows that oil seeds treated with ascorbic acid, pyridoxine and hydrogen peroxide remarkably increase the capacity of germination. We suggest that treatments with such substances can improve the old oil seed germination during storage.

  8. Hydrogen peroxide and hydroxyl radical formation by methylene blue in the presence of ascorbic acid

    International Nuclear Information System (INIS)

    Using ESR we have demonstrated the formation of the ascorbate free radical from sodium ascorbate, methylene blue and light. In oxygen uptake experiments we have observed the production of hydrogen peroxide while spin trapping experiments have revealed the iron catalyzed production of the hydroxyl free radical in this system. The presence of this highly reactive radical suggests that it could be the radical that initiates free radical damage in this photodynamic system. (orig.)

  9. Scientific Opinion on the safety and efficacy of vitamin C (ascorbic acid, sodium ascorbate, calcium ascorbate, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate as a feed additive for all animal species based on a dossier submitted by DSM Nutritional Products Ltd

    Directory of Open Access Journals (Sweden)

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

    2013-02-01

    Full Text Available Vitamin C is essential for primates, guinea pigs and fish. Vitamin C, in the form of ascorbic acid and its calcium and sodium salts, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate, is safe for all animal species. Setting a maximum content in feed and water for drinking is not considered necessary. Data on the vitamin C consumption of consumers are based on the levels of vitamin C in foodstuffs, including food of animal origin, produced in accordance with current EU legislation on the supplementation of feed with vitamin C. The exposure is far below the guidance level. Any potential contribution of the use of vitamin C in feed is therefore already considered in the above data. Consequently, the use of vitamin C in animal nutrition is not of concern for consumer safety. In the absence of inhalation toxicity studies it would be prudent to assume that inhalation of dust from the additives presents a health hazard to workers. Sodium calcium ascorbyl phosphate is not an irritant to skin and eyes and is unlikely to be a skin sensitiser. This conclusion is extrapolated to sodium ascorbyl phosphate. In the absence of data, ascorbic acid, sodium ascorbate, calcium ascorbate and ascorbyl palmitate should be considered as irritant to skin and eyes and as dermal sensitisers. The supplementation of feed with vitamin C does not pose a risk to the environment. Ascorbic acid, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate are regarded as effective sources of vitamin C when added to feed or water for drinking. Since ascorbic acid, sodium ascorbate, calcium ascorbate and ascorbyl palmitate are authorised for use as antioxidants in food and their function in feed is essentially the same as that in food, no further demonstration of efficacy is considered necessary.

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

    Directory of Open Access Journals (Sweden)

    Parisa Hasanein

    2010-04-01

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

  11. Ascorbate and dehydroascorbic acid as reliable biomarkers of oxidative stress : analytical reproducibility and long-term stability of plasma samples subjected to acidic deproteinization

    OpenAIRE

    Lykkesfeldt, Jens

    2007-01-01

    Lack of post-sampling stability of ascorbate and dehydroascorbic acid and failure to block their in vivo equilibrium have lowered their value as biomarkers of oxidative stress and limited the ability to further investigate their possible role in disease prevention. In the present paper, the analytical reproducibility was tested by repeated analysis of plasma aliquots from one individual over four years. The plasma was subjected to acidic deproteinization with an equal volume of 10% meta-phosp...

  12. Noncovalent nanohybrid of cobalt tetraphenylporphyrin with graphene for simultaneous detection of ascorbic acid, dopamine, and uric acid

    International Nuclear Information System (INIS)

    Highlights: •A noncovalent nanohybrid of cobalt tetraphenylporphyrin with chemically reduced graphene oxide was prepared. •The nanohybrid was characterized by UV–vis spectroscopy, Raman spectroscopy, and atomic force microscopy. •The nanohybrid can be applied to simultaneously detect AA, DA and UA with high sensitivity and low detection limit. -- Abstract: A noncovalent nanohybrid of cobalt tetraphenylporphyrin (CoTPP) with chemically reduced graphene oxide (CRGO) was prepared through ?–? stacking interaction between CRGO and CoTPP. The hybrid (CoTPP-CRGO) was characterized by UV–vis spectroscopy, Raman spectroscopy, and atomic force microscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) at CoTPP-CRGO modified glass carbon electrode (CoTPP-CRGO/GCE) were studied by cyclic voltammetry (CV). Three well-resolved oxidation peaks were obtained. The peak potential separations were 225 and 140 mV for AA and DA, DA and UA respectively. Owing to the synergistic effect of CoTPP and CRGO, CoTPP-CRGO showed faster electron transfer and stronger electrocatalysis than CoTPP, CRGO or their mixture. The proposed modified electrode exhibited linear responses to AA, DA and UA in the ranges of 5.0–200.0 ?M, 0.1–12.0 ?M, 0.5–40 ?M, respectively. The detection limits were 1.2, 0.03, and 0.15 ?M, respectively. It was also applied to detect real samples with a satisfactory result

  13. Avaliação da interferência do ácido ascórbico na detecção da glicosúria / Evaluation of ascorbic acid interference in the detection of glycosuria

    Scientific Electronic Library Online (English)

    Jaime Murilo Fernandes, Costa; Maria Elizabete, Mendes; Nairo Massakazu, Sumita.

    2012-02-01

    Full Text Available INTRODUÇÃO: O ácido ascórbico (vitamina C) é comumente ingerido como suplemento vitamínico. É uma vitamina hidrossolúvel, excretada pela urina e pode interferir nos ensaios laboratoriais, como nas reações de oxirredução para detecção da glicosúria. OBJETIVO: Este trabalho tem como objetivo avaliar a [...] interferência do ácido ascórbico na detecção de glicosúria pelo método de química seca por meio do uso de tiras reagentes. MATERIAIS E MÉTODOS: Amostras de urina foram avaliadas no analisador da marca Clinitek Atlas (Siemens Healthcare Diagnostics Inc., EUA). Foram selecionadas quatro amostras de urina com diferentes concentrações de glicose: 100 mg/dl, 250 mg/dl, 500 mg/dl e 1.000 mg/dl. Para cada concentração de glicose foram criadas cinco alíquotas, adicionando-se uma solução de ácido ascórbico 200 mg/dl, suficiente para obter uma concentração final de ácido ascórbico de 20 mg/dl no primeiro tubo, de 50 mg/dl no segundo tubo, de 270 mg/dl no terceiro tubo, de 1.000 mg/dl no quarto tubo e de 2.000 mg/dl no quinto tubo. Após essa adição, as amostras foram novamente avaliadas no analisador Clinitek Atlas. RESULTADOS: Nas amostras com concentração de 20 mg/dl de ácido, não se evidenciou interferência. Nas concentrações iguais e acima de 50 mg/dl, a interferência do ácido ascórbico se fez presente, sendo que o fato foi caracterizado pelos resultados falso negativos para detecção da glicose urinária. CONCLUSÃO: Os resultados demonstraram a interferência do ácido ascórbico no método da química seca (tiras reagentes), subestimando o nível de glicose urinária. Abstract in english INTRODUCTION: Ascorbic acid (vitamin C) is commonly used as a vitamin supplement. It is a water soluble vitamin, which is excreted through urine and may interfere in laboratory tests as well as redox reactions for urinary glucose detection. OBJECTIVE: This study aims to assess ascorbic acid interfer [...] ence in glycosuria detection by dry chemistry method (reagent strips). MATERIAL AND METHODS: Urine samples were evaluated by using Clinitek Atlas chemistry analyzer (Siemens Healthcare Diagnostics Inc., USA). Four urine samples with different glucose concentrations were selected: 100 mg/dl, 250 mg/dl, 500 mg/dl and > 1,000 mg/dl. 5 aliquots were created for each glucose concentration and a solution of ascorbic acid 200 mg/dl was added, sufficient to obtain a final ascorbic acid concentration of 20 mg/dl in the first tube, 50 mg/dl in the second tube, 270 mg/dl in the third tube, 1,000 mg/dl the fourth tube, and 2,000 mg/dl in the fifth tube. After the addition of ascorbic acid, the samples were reassessed by using Clinitek Atlas chemistry analyzer. RESULTS: There was no interference at concentrations of 20 mg/dl. However, there was ascorbic acid interference at concentrations higher than or equal to 50 mg/dl, which was characterized by false-negative results for urinary glucose detection. CONCLUSION: The results corroborated the interference of ascorbic acid in dry chemistry method (reagent strips) inasmuch as it underestimates urinary glucose levels.

  14. Avaliação da interferência do ácido ascórbico na detecção da glicosúria Evaluation of ascorbic acid interference in the detection of glycosuria

    Directory of Open Access Journals (Sweden)

    Jaime Murilo Fernandes Costa

    2012-02-01

    Full Text Available INTRODUÇÃO: O ácido ascórbico (vitamina C é comumente ingerido como suplemento vitamínico. É uma vitamina hidrossolúvel, excretada pela urina e pode interferir nos ensaios laboratoriais, como nas reações de oxirredução para detecção da glicosúria. OBJETIVO: Este trabalho tem como objetivo avaliar a interferência do ácido ascórbico na detecção de glicosúria pelo método de química seca por meio do uso de tiras reagentes. MATERIAIS E MÉTODOS: Amostras de urina foram avaliadas no analisador da marca Clinitek Atlas (Siemens Healthcare Diagnostics Inc., EUA. Foram selecionadas quatro amostras de urina com diferentes concentrações de glicose: 100 mg/dl, 250 mg/dl, 500 mg/dl e 1.000 mg/dl. Para cada concentração de glicose foram criadas cinco alíquotas, adicionando-se uma solução de ácido ascórbico 200 mg/dl, suficiente para obter uma concentração final de ácido ascórbico de 20 mg/dl no primeiro tubo, de 50 mg/dl no segundo tubo, de 270 mg/dl no terceiro tubo, de 1.000 mg/dl no quarto tubo e de 2.000 mg/dl no quinto tubo. Após essa adição, as amostras foram novamente avaliadas no analisador Clinitek Atlas. RESULTADOS: Nas amostras com concentração de 20 mg/dl de ácido, não se evidenciou interferência. Nas concentrações iguais e acima de 50 mg/dl, a interferência do ácido ascórbico se fez presente, sendo que o fato foi caracterizado pelos resultados falso negativos para detecção da glicose urinária. CONCLUSÃO: Os resultados demonstraram a interferência do ácido ascórbico no método da química seca (tiras reagentes, subestimando o nível de glicose urinária.INTRODUCTION: Ascorbic acid (vitamin C is commonly used as a vitamin supplement. It is a water soluble vitamin, which is excreted through urine and may interfere in laboratory tests as well as redox reactions for urinary glucose detection. OBJECTIVE: This study aims to assess ascorbic acid interference in glycosuria detection by dry chemistry method (reagent strips. MATERIAL AND METHODS: Urine samples were evaluated by using Clinitek Atlas chemistry analyzer (Siemens Healthcare Diagnostics Inc., USA. Four urine samples with different glucose concentrations were selected: 100 mg/dl, 250 mg/dl, 500 mg/dl and > 1,000 mg/dl. 5 aliquots were created for each glucose concentration and a solution of ascorbic acid 200 mg/dl was added, sufficient to obtain a final ascorbic acid concentration of 20 mg/dl in the first tube, 50 mg/dl in the second tube, 270 mg/dl in the third tube, 1,000 mg/dl the fourth tube, and 2,000 mg/dl in the fifth tube. After the addition of ascorbic acid, the samples were reassessed by using Clinitek Atlas chemistry analyzer. RESULTS: There was no interference at concentrations of 20 mg/dl. However, there was ascorbic acid interference at concentrations higher than or equal to 50 mg/dl, which was characterized by false-negative results for urinary glucose detection. CONCLUSION: The results corroborated the interference of ascorbic acid in dry chemistry method (reagent strips inasmuch as it underestimates urinary glucose levels.

  15. Kinetics of reactions of technetium. VIII. Reduction of Tc(VII) by ascorbic acid in HC1 solution

    International Nuclear Information System (INIS)

    The reduction of Tc(VII) by ascorbic acid in HCl solution proceeds according to the equation 2TcO4- + 3C6H8O6 + 10HCl = 2TcCl5- + 3C6H6O6 + 8H2O. The reaction is characterized by an induction period, after the conclusion of which its rate is equal to -d[Tc(VII)]/dt = k[Tc(VII)] x [C6H8O6] [H+]/sup 1.6/, where k = 0.898 + 0.064 liter/sup 2.6//mole/sup 2.6./min at 250C and ? = 2. The reaction mechanism includes a slow step of interaction of TcO3+ ions with C6H8O6 molecules and ascorbate complexes of Tc(IV). The full kinetic equation describing the course of the reaction, including the induction period, is obtained

  16. Simultaneous and sensitive determination of ascorbic acid, dopamine, uric acid, and tryptophan with silver nanoparticles-decorated reduced graphene oxide modified electrode.

    Science.gov (United States)

    Kaur, Balwinder; Pandiyan, Thangarasu; Satpati, Biswarup; Srivastava, Rajendra

    2013-11-01

    In this paper, we report the synthesis of silver nanoparticle-decorated reduced graphene oxide composite (AgNPs/rGO) by heating the mixture of graphene oxide and silver nitrate aqueous solution in the presence of sodium hydroxide. This material was characterized by means of X-ray diffraction, UV-vis spectroscopy, and transmission electron microscopy. AgNPs/rGO based electrochemical sensor was fabricated for the simultaneous determination of ascorbic acid, dopamine, uric acid, and tryptophan. Electrochemical studies were carried out by using cyclic voltammetry, linear sweep voltammetry, and chronoamperometry. AgNPs/rGO modified electrode exhibited excellent electrocatalytic activity, stability, sensitivity, and selectivity with well-separated oxidation peaks toward ascorbic acid, dopamine, uric acid, and tryptophan in the simultaneous determination of their quaternary mixture. The analytical performance of this material as a chemical sensor was demonstrated for the determination of ascorbic acid and dopamine in commercial pharmaceutical samples such as vitamin C tablets and dopamine injections, respectively. The applicability of this sensor was also extended in the determination of uric acid in human urine samples. PMID:23777794

  17. Sorption of molybdoarsenates reduced by ascorbic acid with polyurethane foams based on ethers, esters, and their copolymers

    International Nuclear Information System (INIS)

    Sorption of molybdoarsenates reduced by ascorbic acid from aqueous solutions with polyurethane foams based on ethers (PUF-1), esters (PUF-2), and their copolymers (PUF-3) was studied in relation to the phase weight ratio and solution acidity. It is found that the isotherms of reduced molybdoarsenate sorption refer to the Langmuir isotherms. The sorption coefficients decrease in the series PUF-1>PUF-2>PUF-3. Maximum recovery of reduced molybdoarsenate on polyurethane foams is achieved at pH 0-2; concentration factor is up to 2.5x103

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

    Directory of Open Access Journals (Sweden)

    Minka N. Salka

    2012-05-01

    Full Text Available The aims of this study were to determine the modulating role of ascorbic acid (AA on rectal temperature (RT, heterophil to lymphocyte (H to L ratio and aberrant behaviours of ostrich chicks transported by road for 4 h during hot-dry conditions. Twenty ostrich chicks aged 2.5 months, of both sexes and belonging to the Red Neck breed, served as subjects of the study. The chicks were assigned randomly to AA-treated and control groups, consisting of 10 chicks each. The AA-treated group was administered orally with 100 mg/kg body weight of AA dissolved in 5 mL of sterile water 30 min before transportation, whilst the control group was given the equivalent of sterile water only. The thermal load (TL experienced in the vehicle during transportation fluctuated between 31 °C and 89 °C, as calculated from the ambient temperature and relative humidity. Transportation induced hyperthermia, lymphopenia, heterophilia and aberrant behaviours of pecking, wing fluffing and panting, which were ameliorated by AA administration. The relationships between the TL, journey duration and physiological variables of RT, H to L ratio and aberrant behaviours recorded during transportation were significantly and positively correlated in the control group. In AA-treated group the relationships were not significantly correlated. In conclusion, the results showed for the first time that AA ameliorated the adverse effects of stress caused by road transportation on the aberrant behaviours, RT and H to L ratio of ostrich chicks during the hot-dry season.

  19. Determination of ascorbic acid in individual rat hepatocyte by capillary electrophoresis with electrochemical detection.

    Science.gov (United States)

    Sun, Xuemei; Niu, Yan; Bi, Sai; Zhang, Shusheng

    2008-07-01

    A method for the direct determination of ascorbic acid (AA) in individual rat hepatocyte based on capillary electrophoresis (CE) coupled with electrochemical detection (ECD) using a new kind of homemade carbon fiber micro-disk bundle electrode has been described. Individual rat hepatocytes were injected into a fused-silica capillary with an inner diameter of 25 microm, and lysed by 0.1% sodium dodecylsulfate (SDS) as cell lysis solution. The following conditions were suitable for the determination of AA: running buffer, 1.83 x 10(-2) mol/l Na2HPO4-1.70 x 10(-3) mol/l NaH2PO4 (pH 7.8); separation voltage, 20.0 kV; detection potential, 0.80 V (vs. saturated calomel electrode (SCE)). The concentration limit of detection (LOD) of the method was 1.7 x 10(-6) mol/l at a signal-to-noise (S/N) ratio of 3, and the mass LOD was 3.0 fmol. The linear dynamic range was from 5.0 x 10(-6) to 5.0 x 10(-4) mol/l with a correlation coefficient of 0.9962 for the injection voltage of 5.0 kV and injection time of 10s. The relative standard deviation (R.S.D.) was 0.85% for the migration time and 1.8% for the peak current. This method was successfully applied to AA determination in rat hepatocyte. The recovery was between 91% and 97%, and the amount of AA in single rat hepatocyte ranged from 28 to 63 fmol. PMID:18547879

  20. Kidney fibrosis is independent of the amount of ascorbic acid in mice with unilateral ureteral obstruction.

    Science.gov (United States)

    Nishida, H; Kurahashi, T; Saito, Y; Otsuki, N; Kwon, M; Ohtake, H; Yamakawa, M; Yamada, K-I; Miyata, S; Tomita, Y; Fujii, J

    2014-09-01

    In response to sustained damage to a kidney, fibrosis that can be characterized as the deposition of a collagenous matrix occurs and consequently causes chronic kidney failure. Because most animals used in experiments synthesize ascorbic acid (AsA) from glucose, the roles of AsA in fibrotic kidney diseases are largely unknown. Unilateral ureteric obstruction (UUO) mimics the complex pathophysiology of chronic obstructive nephropathy and is an ideal model for the investigation of the roles of AsA in kidney failure. We examined the impact of a deficiency of Akr1a, a gene that encodes aldehyde reductase and is responsible for the production of AsA, on fibrotic damage caused by UUO in mice. Oxidatively modified DNA was elevated in wild-type and Akr1a-deficient kidneys as a result of UUO to a similar extent, and was only slightly suppressed by the administration of AsA. Even though Akrla-deficient mice could produce only about 10% of the AsA produced by wild-type mice, no difference was observed in collagen I synthesis under pathological conditions. The data implied either a low demand for AsA or the presence of another electron donor for collagen I production in the mouse kidney. Next, we attempted to elucidate the potential causes for oxidative damage in kidney cells during the fibrotic change. We found decreases in mitochondrial proteins, particularly in electron transport complexes, at the initial stage of the kidney fibrosis. The data imply that a dysfunction of the mitochondria leads to an elevation of ROS, which results in kidney fibrosis by stimulating cellular transformation to myofibroblasts. PMID:24735064

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

    Science.gov (United States)

    Zhang, Xin; Wei, Youli; Ding, Yaping

    2014-07-01

    A glassy carbon electrode modified with poly(alizarin red)/electrodeposited graphene (PAR/EGR) composite film was prepared and applied to detect ciprofloxacin (CPFX) in the presence of ascorbic, uric acid and dopamine. The morphology and interface property of PAR/EGR films were examined by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The electrocatalytic oxidation of CPFX on AR/EGR was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The linearity ranged from 4 × 10(-8) to 1.2 × 10(-4) M with a detection limit (S/N=3) of 0.01 ?M. The modified electrode could be applied to the individual determination of CPFX as well as the simultaneous determination of CPFX, ascorbic acid, uric acid and dopamine. This method proved to be a simple, selective and rapid way to determine CPFX in pharmaceutical preparation and biological media. PMID:24952626

  2. Frost decreases content of sugars, ascorbic acid and some quercetin glycosides but stimulates selected carotenes in Rosa canina hips.

    Science.gov (United States)

    Cunja, Vlasta; Mikulic-Petkovsek, Maja; Zupan, Anka; Stampar, Franci; Schmitzer, Valentina

    2015-04-15

    Primary and secondary metabolites of Rosa canina hips were determined by HPLC/MS during ripening and after frost damage. Rose hips were harvested six times from the beginning of September until the beginning of December. Color parameters a*, b* and L* decreased during maturation. Glucose and fructose were the predominant sugars representing up to 92% total sugars, and citric acid was the major organic acid detected in rose hips (constituting up to 58% total organic acids). Total sugar and ascorbic acid content significantly decreased after frost damage; from 42.2 to 25.9g 100g(-1) DW for sugars and from 716.8 to 176.0mg 100g(-1) DW for ascorbic acid. Conversely, ?-carotene and lycopene levels increased in frostbitten rose hips to 22.1 and 113.2mg 100g(-1) DW, respectively. In addition to cyanidin-3-glucoside (highest level in hips was 125.7?g 100g(-1) DW), 45 different phenolic compounds have been identified. The most abundant were proanthocyanidins (their levels amounted up to 90% of total flavanol content) and their content showed no significant differences during maturation. The levels of catechin, phloridzin, flavanones and several quercetin glycosides were highest on the first three sampling dates and decreased after frost. Antioxidant capacity similarly decreased in frostbitten rose hips. Total phenolic content increased until the third sampling and decreased on later samplings. PMID:25768262

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

    Scientific Electronic Library Online (English)

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

    2015-04-01

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

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

    Directory of Open Access Journals (Sweden)

    de Visser Marianne

    2009-11-01

    Full Text Available Abstract Background High dose oral ascorbic acid substantially improved myelination and locomotor function in a Charcot-Marie-Tooth type 1A mouse model. A phase II study was warranted to investigate whether high dose ascorbic acid also has such a substantial effect on myelination in Charcot-Marie-Tooth type 1A patients and whether this treatment is safe. Methods Patients below age 25 years were randomly assigned to receive placebo or ascorbic acid (one gram twice daily in a double-blind fashion during one year. The primary outcome measure was the change over time in motor nerve conduction velocity of the median nerve. Secondary outcome measures included changes in minimal F response latencies, compound muscle action potential amplitude, muscle strength, sensory function, Charcot-Marie-Tooth neuropathy score, and disability. Results There were no significant differences between the six placebo-treated (median age 16 years, range 13 to 24 and the five ascorbic acid-treated (19, 14 to 24 patients in change in motor nerve conduction velocity of the median nerve (mean difference ascorbic acid as opposed to placebo treatment of 1.3 m/s, confidence interval -0.3 to 3.0 m/s, P = 0.11 or in change of any of the secondary outcome measures over time. One patient in the ascorbic acid group developed a skin rash, which led to discontinuation of the study medication. Conclusion Oral high dose ascorbic acid for one year did not improve myelination of the median nerve in young Charcot-Marie-Tooth type 1A patients. Treatment was relatively safe. Trial registration Current Controlled Trials ISRCTN56968278, ClinicalTrials.gov NCT00271635.

  5. Chemical repair of base lesions, AP-sites, and strand breaks on plasmid DNA in dilute aqueous solution by ascorbic acid

    International Nuclear Information System (INIS)

    Highlights: •We report a novel mechanism of radiation protection of DNA by chemical activity of ascorbic acid. •The “chemical repair” of DNA damage was revealed using biochemical assay and chemical kinetics analysis. •We found that ascorbic acid significantly repairs precursors of nucleobase lesions and abasic sites. •However, ascorbic acid seldom repairs precursors of DNA-strand breaks. -- Abstract: We quantified the damage yields produced in plasmid DNA by ?-irradiation in the presence of low concentrations (10–100 ?M) of ascorbic acid, which is a major antioxidant in living systems, to clarify whether it chemically repairs radiation damage in DNA. The yield of DNA single strand breaks induced by irradiation was analyzed with agarose gel electrophoresis as conformational changes in closed circular plasmids. Base lesions and abasic sites were also observed as additional conformational changes by treating irradiated samples with glycosylase proteins. By comparing the suppression efficiencies to the induction of each DNA lesion, in addition to scavenging of the OH radicals derived from water radiolysis, it was found that ascorbic acid promotes the chemical repair of precursors of AP-sites and base lesions more effectively than those of single strand breaks. We estimated the efficiency of the chemical repair of each lesion using a kinetic model. Approximately 50–60% of base lesions and AP-sites were repaired by 10 ?M ascorbic acid, although strand breaks were largely unrepaired by ascorbic acid at low concentrations. The methods in this study will provide a route to understanding the mechanistic aspects of antioxidant activity in living systems

  6. Protective effects of ascorbic acid pretreatment in a rat model of intestinal ischemia-reperfusion injury: a histomorphometric study Efeito protetor do pré-tratamento com ácido ascóbico em modelo experimental de isquemia-reperfusão intestinal: um estudo histomorfométrico

    OpenAIRE

    Oscar Haruo Higa; Edwin Roger Parra; Alexandre Muxfeldt Ab'Saber; Cecilia Farhat; Rita Higa; Vera Luiza Capelozzi

    2007-01-01

    BACKGROUND: Ascorbic acid has shown promise in attenuation of intestinal ischemia-reperfusion (I/R) injury. The aim of this study was to determine the protective effects of ascorbic acid on intestinal morphology during IR injury in rats. MATERIALS AND METHODS: We examined morphological changes in the small intestine of Wistar rats after (i) 40 minutes of ischemia (I), (ii) ischemia followed by 30 min of reperfusion (IR), (iii) ischemia with ascorbic acid (IA), (iv) ischemia followed by reperf...

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

    Directory of Open Access Journals (Sweden)

    Chase F Kempinski

    2013-01-01

    Full Text Available Ascorbic acid is a potent antioxidant that detoxifies reactive oxygen species when plants are exposed to unfavorable environmental conditions. In addition to its antioxidant properties, ascorbic acid and its biosynthetic precursors fulfill a variety of other physiological and molecular functions. A mutation in the ascorbic acid biosynthesis gene VTC1, which encodes GDP-mannose pyrophosphorylase, results in conditional root growth inhibition in the presence of ammonium. To isolate suppressors of vtc1-1, which is in the Arabidopsis Columbia-0 background, seeds of the mutant were subjected to ethyl methanesulfonate mutagenesis. A suppressor mutant of vtc1-1 2, svt2, with wild-type levels of ascorbic acid and root growth similar to the wild type in the presence of ammonium was isolated. Interestingly, svt2 has Arabidopsis Landsberg erecta features, although svt2 is delayed in flowering and has an enlarged morphology. Moreover, the svt2 genotype shares similarities with Ler polymorphism markers and sequences, despite the fact that the mutant derived from mutagenesis of Col-0 vtc1-1 seed. We provide evidence that svt2 is not an artifact of the experiment, a contamination of Ler seed, or a result of outcrossing of the svt2 mutant with Ler pollen. Instead, our results show that svt2 exhibits transgenerational genotypic and phenotypic instability, which is manifested in a fraction of svt2 progeny, producing revertants that have Col-like phenotypic and genotypic characteristics. Some of those Col-like revertants then revert back to svt2-like plants in the subsequent generation. Our findings have important implications for undiscovered phenomena in transmitting genetic information in addition to the Mendelian laws of inheritance. Our results suggest that stress can trigger a genome restoration mechanism that could be advantageous for plants to survive environmental changes for which the ancestral genes were better adapted.

  8. Analytical potential of the reaction between p-phenylenediamines and peroxodisulfate for kinetic spectrophotometric determination of traces of ascorbic acid.

    Science.gov (United States)

    Rustoiu-Csavdari, Alexandra; Nickel, Ulrich

    2002-11-01

    The analytical potential of the redox reactions between N, N-dimethyl- or N, N, N', N'-tetramethyl- p-phenylenediamine (DMPPD or TMPPD, respectively) and peroxodisulfate in acidic media for kinetic spectrophotometric determination of trace amounts of ascorbic acid (AA) has been investigated. The goal was to explore reaction conditions ensuring an excess or a deficit of S(2)O(8)(2-), and to identify some kinetic features of the global process for the purpose of calibration. Because the induction period of the overall reaction increases significantly in the presence of micromolar amounts of AA, the most suitable calibration graphs are generated by plots of induction period against the analyte concentration. The best sensitivity was achieved for oxidation of DMPPD with a deficit of S(2)O(8)(2-). The calibration line obtained has an RSD of 2.6% for 4 x 10(-6) mol L(-1) AA (n=3) and the detection limit is 4 x 10(-8) mol L(-1) (7 micro g L(-1)), a value comparable with the best mentioned by the literature. No systematic study of interferents was performed. Instead, the effect of buffer reagents (phosphate, phthalate, citrate) and dissolved oxygen on the results is discussed. Experiments were performed under closely controlled conditions. This is the first report of ascorbic acid analysis in which "contamination" by environmental oxygen was prevented by rinsing all vessels and saturating all solutions with argon, an approach which enables determination of the actual ascorbic acid content. Because of the effort involved, however, the method might not be suitable for routine analysis. Analysis of a commercially available vitamin C pellet gave good results when a "special" calibration graph, obtained in the presence of all other constituents of the sample except AA, was employed. The AA was "removed" from the pellet by oxidation with environmental air. Although it seems rather elaborate, this procedure did not require prior preparation of the sample nor extraction and/or concentration of ascorbic acid from it. PMID:12458429

  9. Inhibitory action of antioxidants (ascorbic acid or ?-tocopherol) on seizures and brain damage induced by pilocarpine in rats / Ação inibitória de antioxidantes (ácido ascórbico e ?-tocoferol) nas convulsões e dano cerebral em ratos induzidos pela pilocarpina

    Scientific Electronic Library Online (English)

    Adriana da Rocha, Tomé; Paulo Michel Pinheiro, Ferreira; Rivelilson Mendes de, Freitas.

    2010-06-01

    Full Text Available A epilepsia de lobo temporal é a mais comum forma de epilepsia em humanos. O estresse oxidativo é um dos mecanismos de morte celular induzida pelas crises convulsivas. Os compostos antioxidantes apresentam efeitos neuroprotetores devido à sua capacidade de inibir a produção de radicais livres. Os ob [...] jetivos do presente trabalho foram estudar de forma comparativa a ação inibitória de antioxidantes (ácido ascórbico e ?-tocoferol) sobre as alterações comportamentais e histopatológicas no hipocampo de ratos após convulsões induzidas pela pilocarpina. A fim de determinar os efeitos neuroprotetores destas drogas, o presente trabalho estudou os efeitos do ácido ascórbico (250 ou 500 mg/kg, i.p.) e do ?-tocoferol (200 ou 400 mg/kg, i.p.) sobre o comportamento e as lesões cerebrais observados após convulsões induzidas pela pilocarpina (400 mg/kg, i.p., P400), em ratos. As injeções de ácido ascórbico ou ?-tocoferol antes da administração de pilocarpina reduzem o número de animais que convulsionam. Estes achados sugerem que os radicais livres podem induzir o desenvolvimento de lesão cerebral durante as crises epilépticas. No modelo P400, o ácido ascórbico e o ?-tocoferol, diminuem significativamente os danos cerebrais. Os compostos antioxidantes podem exercer efeitos neuroprotetores, e esses resultados podem estar associados à inibição da produção de radicais livres. Estes resultados sugerem um promissor potencial terapêutico tanto para o ácido ascórbico quanto para o ?-tocoferol no tratamento de doenças neurodegenerativas. Abstract in english Temporal lobe epilepsy is the most common form of epilepsy in humans. Oxidative stress is a mechanism of cell death induced by seizures. Antioxidant compounds have neuroprotective effects due to their ability to inhibit free radical production. The objectives of this work were to comparatively study [...] the inhibitory action of antioxidants (ascorbic acid or ?-tocopherol) on behavioral changes and brain damage induced by high doses of pilocarpine, aiming to further clarify the mechanism of action of these antioxidant compounds. In order to determinate neuroprotective effects, we studied the effects of ascorbic acid (250 or 500 mg/kg, i.p.) and ?-tocopherol (200 or 400 mg/kg, i.p.) on the behavior and brain lesions observed after seizures induced by pilocarpine (400 mg/kg, i.p., P400 model) in rats. Ascorbic acid or ?-tocopherol injections prior to pilocarpine suppressed behavioral seizure episodes. These findings suggested that free radicals can be produced during brain damage induced by seizures. In the P400 model, ascorbic acid and ?-tocopherol significantly decreased cerebral damage percentage. Antioxidant compounds can exert neuroprotective effects associated with inhibition of free radical production. These results highlighted the promising therapeutic potential of ascorbic acid and ?-tocopherol in treatments for neurodegenerative diseases.

  10. Inhibitory action of antioxidants (ascorbic acid or ?-tocopherol on seizures and brain damage induced by pilocarpine in rats Ação inibitória de antioxidantes (ácido ascórbico e ?-tocoferol nas convulsões e dano cerebral em ratos induzidos pela pilocarpina

    Directory of Open Access Journals (Sweden)

    Adriana da Rocha Tomé

    2010-06-01

    Full Text Available Temporal lobe epilepsy is the most common form of epilepsy in humans. Oxidative stress is a mechanism of cell death induced by seizures. Antioxidant compounds have neuroprotective effects due to their ability to inhibit free radical production. The objectives of this work were to comparatively study the inhibitory action of antioxidants (ascorbic acid or ?-tocopherol on behavioral changes and brain damage induced by high doses of pilocarpine, aiming to further clarify the mechanism of action of these antioxidant compounds. In order to determinate neuroprotective effects, we studied the effects of ascorbic acid (250 or 500 mg/kg, i.p. and ?-tocopherol (200 or 400 mg/kg, i.p. on the behavior and brain lesions observed after seizures induced by pilocarpine (400 mg/kg, i.p., P400 model in rats. Ascorbic acid or ?-tocopherol injections prior to pilocarpine suppressed behavioral seizure episodes. These findings suggested that free radicals can be produced during brain damage induced by seizures. In the P400 model, ascorbic acid and ?-tocopherol significantly decreased cerebral damage percentage. Antioxidant compounds can exert neuroprotective effects associated with inhibition of free radical production. These results highlighted the promising therapeutic potential of ascorbic acid and ?-tocopherol in treatments for neurodegenerative diseases.A epilepsia de lobo temporal é a mais comum forma de epilepsia em humanos. O estresse oxidativo é um dos mecanismos de morte celular induzida pelas crises convulsivas. Os compostos antioxidantes apresentam efeitos neuroprotetores devido à sua capacidade de inibir a produção de radicais livres. Os objetivos do presente trabalho foram estudar de forma comparativa a ação inibitória de antioxidantes (ácido ascórbico e ?-tocoferol sobre as alterações comportamentais e histopatológicas no hipocampo de ratos após convulsões induzidas pela pilocarpina. A fim de determinar os efeitos neuroprotetores destas drogas, o presente trabalho estudou os efeitos do ácido ascórbico (250 ou 500 mg/kg, i.p. e do ?-tocoferol (200 ou 400 mg/kg, i.p. sobre o comportamento e as lesões cerebrais observados após convulsões induzidas pela pilocarpina (400 mg/kg, i.p., P400, em ratos. As injeções de ácido ascórbico ou ?-tocoferol antes da administração de pilocarpina reduzem o número de animais que convulsionam. Estes achados sugerem que os radicais livres podem induzir o desenvolvimento de lesão cerebral durante as crises epilépticas. No modelo P400, o ácido ascórbico e o ?-tocoferol, diminuem significativamente os danos cerebrais. Os compostos antioxidantes podem exercer efeitos neuroprotetores, e esses resultados podem estar associados à inibição da produção de radicais livres. Estes resultados sugerem um promissor potencial terapêutico tanto para o ácido ascórbico quanto para o ?-tocoferol no tratamento de doenças neurodegenerativas.

  11. Ascorbate protects endothelial barrier function during septic insult: Role of protein phosphatase type 2A

    OpenAIRE

    Han, Min; Pendem, Suresh; Teh, Suet Ling; Sukumaran, Dinesh K.; Wu, Feng; Wilson, John X.

    2009-01-01

    Endothelial barrier dysfunction contributes to morbidity in sepsis. We tested the hypothesis that raising the intracellular ascorbate concentration protects the endothelial barrier from septic insult by inhibiting protein phosphatase type 2A. Monolayer cultures of microvascular endothelial cells were incubated with ascorbate, dehydroascorbic acid (DHAA), NADPH oxidase inhibitors apocynin and diphenyliodonium, or PP2A inhibitor okadaic acid, and then were exposed to septic insult (lipopolysacc...

  12. ZnO-CuxO/polypyrrole nanocomposite modified electrode for simultaneous determination of ascorbic acid, dopamine, and uric acid.

    Science.gov (United States)

    Ghanbari, Kh; Hajheidari, N

    2015-03-15

    Novel zinc oxide (ZnO) nanosheets and copper oxide (CuxO, CuO, and Cu2O) decorated polypyrrole (PPy) nanofibers (ZnO-CuxO-PPy) have been successfully fabricated for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The morphology and structure of ZnO-CuxO-PPy nanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. Compared with the bare glassy carbon electrode (GCE), PPy/GCE, CuxO-PPy/GCE, and ZnO-PPy/GCE, ZnO-CuxO-PPy/GCE exhibits much higher electrocatalytic activities toward the oxidation of AA, DA, and UA with increasing peak currents and decreasing oxidation overpotentials. Cyclic voltammetry (CV) results show that AA, DA, and UA could be detected selectively and sensitively at ZnO-CuxO-PPy/GCE with peak-to-peak separation of 150 and 154 mV for AA-DA and DA-UA, respectively. The calibration curves for AA, DA, and UA were obtained in the ranges of 0.2 to 1.0 mM, 0.1 to 130.0 ?M, and 0.5 to 70.0 ?M, respectively. The lowest detection limits (signal/noise=3) were 25.0, 0.04, and 0.2 ?M for AA, DA, and UA, respectively. With good selectivity and sensitivity, the current method was applied to the determination of DA in injectable medicine and UA in urine samples. PMID:25576954

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

    International Nuclear Information System (INIS)

    A palmitoyl derivative of ascorbic acid 2-glucoside, 6-palmitoyl ascorbic acid-2-glucoside (PAsAG), which possess good antioxidant properties, is examined for radioprotection in vitro, ex vivo and in vivo models. PAsAG protected plasmid DNA from gamma-radiation induced damages under in vitro conditions. Presence of 1.6 mM PAsAG inhibited the disappearance of ccc (covalently closed circular) form of plasmid pBR322 with a dose modifying factor of 1.5. Comet assay studies on mouse spleen cells exposed to 6 Gy gamma-radiation (ex vivo) in presence and absence of PAsAG revealed that cellular DNA was effectively protected by this compound from radiation induced damages. Oral administration of 80 mg/kg body weight of PAsAG to mice 1 hour prior to 6 Gy whole body gamma-radiation exposure, efficiently protected cellular DNA in tissues such as spleen, bone marrow and blood, from radiation induced damages as indicated by alkaline comet assay. Oxidative stress in tissues such as liver and brain of mice, following whole body exposure to various doses of gamma-radiation (2-8 Gy), monitored as levels of glutathione (GSH) and peroxidation of lipids, were found considerably reduced when PAsAG was orally administered (80 mg/kg body weight) to the mice one hour prior to the radiation exposure. PAsAG administration improved the per cent survival of mice following exposure to 10 Gy whole body gamma-radiation. Thus PAsAG could act as a radioprotector under in vitro, ex vivo and in vivo conor under in vitro, ex vivo and in vivo conditions of ionizing-radiation exposure. (author)

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

    Directory of Open Access Journals (Sweden)

    Nahed S. Hassan

    2007-01-01

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

  15. Electrochemical determination of dopamine in the presence of ascorbic acid based on the gold nanorods/carbon nanotubes composite film

    Energy Technology Data Exchange (ETDEWEB)

    Deng Chunyan, E-mail: dengchunyan81@126.com [Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha, 410083 (China); Chen Jinzhuo; Yang Minghui [Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha, 410083 (China); Nie Zhou [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Si Shihui [Key Laboratory of Resources Chemistry of Nonferrous Metals, Central South University, Changsha, 410083 (China)

    2011-10-01

    Highlights: > The GNR/CNT/GC electrode was fabricated simply. It has higher catalytic activity towards the oxidation of DA and ascorbic acid (AA). The selective determination of DA was carried out with low detection limit (0.8 nM, S/N = 3). The proposed method was feasible to detect the concentration of DA in human blood serum. - Abstract: In this paper, the gold nanorods (GNRs)/multiwalled carbon nanotubes (CNT) composite film-modified glassy carbon (GC) electrode was fabricated simply by the electrostatic interaction between the positively charged GNRs and the negatively charged CNT. And the GNRs/CNT/GC electrode was used for the selective and sensitive determination of dopamine (DA) in the presence of ascorbic acid (AA). It was found that the GNRs/CNT/GC electrode had higher catalytic activity towards the oxidation of DA and ascorbic acid (AA) comparing with the bare GC and CNT/GC electrodes. It may be due to the synergic effect of GNRs and CNT, because the surface area of the GNRs/CNT/GC electrode increased, the edge plan sites presented on the CNT surface can improve the electron transfer between the modified electrode and DA, and the rod-shaped gold may be served as the mediator for the oxidation of dopamine and provided the electrocatalytic ability. Moreover, the voltammetric peaks of AA and DA were separated enough at the GNRs/CNT/GC electrode, which was sufficiently enough for the selective determination of DA. Thus, the selective determination of DA was carried out with low detection limit (0.8 nM, S/N = 3). Also it was obtained that the proposed method was feasible to detect the concentration of DA in human blood serum. Therefore, it can be concluded that the GNRs/CNT modified electrode may be advantageous for the DA determination.

  16. Electrochemical determination of dopamine in the presence of ascorbic acid based on the gold nanorods/carbon nanotubes composite film

    International Nuclear Information System (INIS)

    Highlights: ? The GNR/CNT/GC electrode was fabricated simply. It has higher catalytic activity towards the oxidation of DA and ascorbic acid (AA). The selective determination of DA was carried out with low detection limit (0.8 nM, S/N = 3). The proposed method was feasible to detect the concentration of DA in human blood serum. - Abstract: In this paper, the gold nanorods (GNRs)/multiwalled carbon nanotubes (CNT) composite film-modified glassy carbon (GC) electrode was fabricated simply by the electrostatic interaction between the positively charged GNRs and the negatively charged CNT. And the GNRs/CNT/GC electrode was used for the selective and sensitive determination of dopamine (DA) in the presence of ascorbic acid (AA). It was found that the GNRs/CNT/GC electrode had higher catalytic activity towards the oxidation of DA and ascorbic acid (AA) comparing with the bare GC and CNT/GC electrodes. It may be due to the synergic effect of GNRs and CNT, because the surface area of the GNRs/CNT/GC electrode increased, the edge plan sites presented on the CNT surface can improve the electron transfer between the modified electrode and DA, and the rod-shaped gold may be served as the mediator for the oxidation of dopamine and provided the electrocatalytic ability. Moreover, the voltammetric peaks of AA and DA were separated enough at the GNRs/CNT/GC electrode, which was sufficiently enough for the selective determination of DA. Thus, the selective determination of DA was cathe selective determination of DA was carried out with low detection limit (0.8 nM, S/N = 3). Also it was obtained that the proposed method was feasible to detect the concentration of DA in human blood serum. Therefore, it can be concluded that the GNRs/CNT modified electrode may be advantageous for the DA determination.

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

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    Klingelhoeffer Christoph

    2012-05-01

    Full Text Available Abstract Background Ascorbic acid demonstrates a cytotoxic effect by generating hydrogen peroxide, a reactive oxygen species (ROS involved in oxidative cell stress. A panel of eleven human cancer cell lines, glioblastoma and carcinoma, were exposed to serial dilutions of ascorbic acid (5-100?mmol/L. The purpose of this study was to analyse the impact of catalase, an important hydrogen peroxide-detoxifying enzyme, on the resistance of cancer cells to ascorbic acid mediated oxidative stress. Methods Effective concentration (EC50 values, which indicate the concentration of ascorbic acid that reduced the number of viable cells by 50%, were detected with the crystal violet assay. The level of intracellular catalase protein and enzyme activity was determined. Expression of catalase was silenced by catalase-specific short hairpin RNA (sh-RNA in BT-20 breast carcinoma cells. Oxidative cell stress induced apoptosis was measured by a caspase luminescent assay. Results The tested human cancer cell lines demonstrated obvious differences in their resistance to ascorbic acid mediated oxidative cell stress. Forty-five percent of the cell lines had an EC50?>?20?mmol/L and fifty-five percent had an EC50?50 of 2.6–5.5?mmol/L, glioblastoma cells were the most susceptible cancer cell lines analysed in this study. A correlation between catalase activity and the susceptibility to ascorbic acid was observed. To study the possible protective role of catalase on the resistance of cancer cells to oxidative cell stress, the expression of catalase in the breast carcinoma cell line BT-20, which cells were highly resistant to the exposure to ascorbic acid (EC50: 94,9?mmol/L, was silenced with specific sh-RNA. The effect was that catalase-silenced BT-20 cells (BT-20 KD-CAT became more susceptible to high concentrations of ascorbic acid (50 and 100?mmol/L. Conclusions Fifty-five percent of the human cancer cell lines tested were unable to protect themselves against oxidative stress mediated by ascorbic acid induced hydrogen peroxide production. The antioxidative enzyme catalase is important to protect cancer cells against cytotoxic hydrogen peroxide. Silenced catalase expression increased the susceptibility of the formerly resistant cancer cell line BT-20 to oxidative stress.

  18. Effect of varying levels of dietary vitamin C (ascorbic acid on growth, survival and hematology of juvenile tilapia, Oreochromis karongae (Trewavas 1941 reared in aquaria

    Directory of Open Access Journals (Sweden)

    A. R. Nsonga

    2010-02-01

    Full Text Available Vitamin C (ascorbic acid requirement of juvenile Oreochromis karongae was studied by incorporating varying levels of ascorbyl-2-polyphosphate in a 40% crude protein diet to obtain 0, 20, 40, 60 and 80 mg ascorbic acid equivalent kg-1 diet. Juvenile fish of 3.7g ± 0.02g initial body weight were used for the study. After 84 days of the experiment, the fish fed AA- supplemented diets had significantly (P < 0.05 higher specific growth rate protein conversion efficiency and protein efficiency ratio; and significantly (P < 0.05 better feed conversion ratios than non supplemented fish. Fish fed non supplemented diet recorded a 33 % rate of mortality, where as those fed with a diet supplemented with 60 mg ascorbic acid kg-1 had mortality as low as 4.4 %. Hematological indices showed a significant increase (P < 0.05 with dietary AA level. Diet containing 60 mg kg-1 of AA showed the maximum growth performance, while the broken line model gave 51 mg ascorbic acid kg-1 diet as the optimal level required by juvenile O. karongae. Our data show that ascorbic acid is essential for O. karongae growth performance.

  19. PENGARUH ASAM AKROBAT TERHADAP PEMBENTUKAN GEL MIOFIBRIL IKAN MATA BESAR (Selar crumenophthalnus [effect of ascorbic acid on gel formation of myofibril from big eye scad fish (Selar crumenophthalnus

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    Yuli Witono

    2005-08-01

    Full Text Available Effect of ascorbic acid on gel formation of myofibril from big eye scad fish (Selar crumenophthalnuswere studied for its development as food ingredient. Myofibril was galled by the addition of various concentrations of ascorbic acid (0, 0.1, 0.2, 0.3 and 0.4% and the gels were then characterized for its cooking loss, of the gel, but at 0.4% the cooking loss of gel increased significantly. Accordingly, the WHC of the gel changed insignificantly with the ascorbic acid addition below 0.3%, and decrease sharply in the addition of 0.4%. Gel textures were affected by the addition of ascorbic acid at all levels, namely 29.9 ± 1.9, 31.0 ± 0.3, 35.4 ± 0.4, 46.7 ± 1.5, and 115.7 ± 3.2 g/7 mm for 0, 0.1, 0.2, 0.3 and 0.4%, respectively. Sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS-PAGE showed that addition of ascorbic acid drove formation odfdisulphide bond in the myosin heavy chain (MHC and other myofirillar proteins, resulting in the development of a strong three dimensions structure I myofibril gel as shown by microscopic structure.

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

    Directory of Open Access Journals (Sweden)

    J.N. Kabira

    2011-01-01

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

  1. The ameliorative effect of ascorbic acid and Ginkgo biloba on learning and memory deficits associated with fluoride exposure

    OpenAIRE

    Raghu, Jetti; Raghuveer, Vasudeva C.; Rao, Mallikarjuna C.; Somayaji, Nagabhooshana S.; Babu, Prakash B.

    2013-01-01

    Chronic exposure to fluoride causes dental and skeletal fluorosis. Fluoride exposure is also detrimental to soft tissues and organs. The present study aimed at evaluation of the effect of Ginkgo biloba and ascorbic acid on learning and memory deficits caused by fluoride exposure. Male Wistar rats were divided into five groups (n=6). Group 1 control. Groups 2 to 5 received 100 ppm of sodium fluoride over 30 days. Groups 3, 4 and 5 were further treated for 15 days receiving respectively 1% gum ...

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

    OpenAIRE

    Mirabdollbaghi, J.; Hosseini, S. A.; Lotfollahian, H.; Mahdavi Ali; Kalanie Mehdi

    2006-01-01

    An experiment was conducted to study the effects of different water source, saline water (Tap water +2 g L-1 Na) and tape water with a diet that supplemented by three level of Ascorbic Acid (0, 1.5 and 3 g kg-1 of diet) on laying hen`s performance and egg shell quality. This trail was carried out on 108 commercial laying hens (Hy-Line) 32 weeks old for 12 weeks. All of the data were subjected to Two- way analysis of variance test. The result showed that egg production (%), egg weight (g), egg...

  3. Simultaneous Electrochemical Detection of Dopamine and Ascorbic Acid Using an Iron Oxide/Reduced Graphene Oxide Modified Glassy Carbon Electrode

    OpenAIRE

    Teo Peik-See; Alagarsamy Pandikumar; Huang Nay-Ming; Lim Hong-Ngee; Yusran Sulaiman

    2014-01-01

    The fabrication of an electrochemical sensor based on an iron oxide/graphene modified glassy carbon electrode (Fe3O4/rGO/GCE) and its simultaneous detection of dopamine (DA) and ascorbic acid (AA) is described here. The Fe3O4/rGO nanocomposite was synthesized via a simple, one step in-situ wet chemical method and characterized by different techniques. The presence of Fe3O4 nanoparticles on the surface of rGO sheets was confirmed by FESEM and TEM images. The electrochemical behavior of Fe3O4/r...

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

    OpenAIRE

    Khorasani-motlagh, Mozhgan; Noroozifar, Meissam

    2004-01-01

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

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

    Science.gov (United States)

    Liu, Xudong; Zhang, Yuchao; Li, Jinquan; Wang, Dong; Wu, Yang; Li, Yan; Lu, Zhisong; Yu, Samuel C T; Li, Rui; Yang, Xu

    2014-01-01

    Single-walled carbon nanotubes (SWCNTs) have shown increasing promise in the field of biomedicine, especially in applications related to the nervous system. However, there are limited studies available on the neurotoxicity of SWCNTs used in vivo. In this study, neurobehavioral changes caused by SWCNTs in mice and oxidative stress were investigated. The results of ethological analysis (Morris water maze and open-field test), brain histopathological examination, and assessments of oxidative stress (reactive oxygen species [ROS], malondialdehyde [MDA], and glutathione [GSH]), inflammation (nuclear factor ?B, tumor necrosis factor ?, interleukin-1?), and apoptosis (cysteine-aspartic acid protease 3) in brains showed that 6.25 and 12.50 mg/kg/day SWCNTs in mice could induce cognitive deficits and decreased locomotor activity, brain histopathological alterations, and increased levels of oxidative stress, inflammation, and apoptosis in mouse brains; however, 3.125 mg/kg/day SWCNTs had zero or minor adverse effects in mice, and these effects were blocked by concurrent administration of ascorbic acid. Down-regulation of oxidative stress, inflammation, and apoptosis were proposed to explain the neuroprotective effects of ascorbic acid. This work suggests SWCNTs could induce cognitive deficits and decreased locomotor activity, and provides a strategy to avoid the adverse effects. PMID:24596461

  6. Effect of the ascorbic acid treatment on the NADHd-positive myenteric neurons of diabetic rats proximal colon

    Scientific Electronic Library Online (English)

    Jacqueline Nelisis, Zanoni; Renata Virginia Fernandes, Pereira; Priscila de, Freitas.

    2007-01-01

    Full Text Available O efeito do ácido ascórbico sobre neurônios mioentéricos do colo proximal de ratos diabéticos foi avaliado. Quinze ratos com 90 dias foram divididos nos grupos: controle, diabéticos e diabéticos tratados com ácido ascórbico (DA). Após 120 dias de tratamento diário com ácido ascórbico os segmentos in [...] testinais foram submetidos à técnica histoquímica NADH-diaforase (NADHd). A densidade neuronal, em uma área de 14,11 mm² para cada segmento, e o perfil do corpo celular de neurônios (500 neurônios/grupo) foram avaliados. O grupo DA apresentou maior densidade neuronal (33.4 %) em relação aos animais diabéticos (p Abstract in english The aim of this work was to study the effect of the ascorbic acid on the myenteric neurons of diabetic rats proximal colon. Fifteen rats (90 days old) were divided into three groups: control, untreated diabetic and treated diabetic with ascorbic acid (DA). After 120 days of daily treatment with asco [...] rbic acid, the intestinal segments were submitted to the NADH-diaphorase (NADHd) histochemistry technique to expose the myenteric neurons. The group DA showed a higher neuronal density (33.4 %) when compared to the untreated diabetic animals (p

  7. Monitoring of oxidation steps of ascorbic acid redox reaction by kinetics-sensitive voltcoulometry in unsupported and supported aqueous solutions and real samples.

    Science.gov (United States)

    Orlický, Jozef; Gmucová, Katarína; Thurzo, Ilja; Pavlásek, Juraj

    2003-04-01

    Aqueous solutions of ascorbic acid in unsupported and supported aqueous solutions and real samples were studied by the kinetics-sensitive double-step voltcoulommetric method with the aim to contribute to a better understanding of its behavior in biological systems. The data obtained from measurements made on analytes prepared in the laboratory, as well as those made on real samples (some commercial orange drinks, flash of the fresh fruits) point to the redox reaction of L-ascorbic acid (L-AH2) being very sensitive to both the presence of dissolved gaseous species (O2, CO2) and the ionic strenght in the analyte. Either the dissolved gaseous species, or the higher ionic strength caused by both the presence of supporting electrolyte and increased total concentration of ascorbic acid, respectively, give birth to the degradation of L-AH2. Naturally, the highest percentage of L-AH2 was spotted in fresh fruit. PMID:12725383

  8. Erythrocyte catalase inactivation (H2O2 production) by ascorbic acid and glucose in the presence of aminotriazole: role of transition metals and relevance to diabetes.

    Science.gov (United States)

    Ou, P; Wolff, S P

    1994-11-01

    Erythrocytes exposed to ascorbic acid in the presence of aminotriazole undergo a dose- and time-dependent inactivation of endogenous catalase which is proportional to environmental hydrogen peroxide (H2O2) concentrations. The production of H2O2 seems to be dependent upon the availability of transition metal chelatable by o-phenanthroline (OPT), although the kinetics of catalase inactivation and H2O2 production by externally added copper ions in the presence of OPT is complex. Furthermore, although glucose is also able to undergo a transition-metal-catalysed oxidation yielding H2O2, the production of H2O2 by glucose seems to be a minor process by comparison with ascorbic acid oxidation. Indeed, on the basis of these data, transition-metal-catalysed ascorbic acid oxidation is likely to be a more important source of oxidative stress in the diabetic state than hyperglycaemia. PMID:7980465

  9. D-glucosone and L-sorbosone as putative intermediates in the biosynthesis of L-ascorbic acid in plants

    International Nuclear Information System (INIS)

    In plants, biosynthesis of L-ascorbic acid (AA) from D-glucose (glc) proceeds without carbon chain inversion. This requires oxidation of C1 and C2, and epimerization at C5. Neither sequence of reactions nor enzymes involved is yet known. To examine the overall reaction the authors fed D-[6-14C]glucosone to bean seedlings. It was converted to AA as effectively as [6-14C]glc with virtually no redistribution of label into the opposite terminal carbon. In other studies, a NADP-dependent L-sorbosone dehydrogenase that synthesized AA was isolated from bean and spinach leaves. Partial purification by precipitation at 45-55% (NH4)2SO4, fractionation on DEAE cellulose, and molecular sieving on Sephadex G-200 gave 30-fold purification. The enzyme was stable at -200C for several months. The apparent Km for sorbosone (0.9 mM NADP+) was 11.3+/-1.9 mM and for NADP+ (50 mM sorbosone) was 145+/-47 ?M. The relatively high Km's may reflect a two-step process or selection of a minor isomeric forms or sorbosone. A pathway (possibly involving phosphorylated intermediates) is suggested: D-Glucose?D-Glucosone?L-Sorbosone?L-Ascorbic acid

  10. Furan Occurrence in Starchy Food Model Systems Processed at High Temperatures: Effect of Ascorbic Acid and Heating Conditions

    DEFF Research Database (Denmark)

    Mariotti, Mari?a; Granby, Kit

    2012-01-01

    Furan, a potential carcinogen, has been detected in highly consumed starchy foods, such as bread and snacks; however, research on furan generation in these food matrixes has not been undertaken, thus far. The present study explored the effect of ascorbic acid addition and cooking methods (frying and baking) over furan occurrence and its relation with the non-enzymatic browning in a wheat flour starchy food model system. Results showed that furan generation significantly increased in the presence of ascorbic acid after 7 min of heating (p <0.05). The strongest effect was observed for baked products. Additionally, the furan content in fried products increased with the increase of the oil uptake levels. As for Maillard reactions, in general, the furan level in all samples linearly correlated with their degree of non-enzymatic browning, represented by L* and a* color parameters (e.g., wheat flour baked samples showed a R2 of 0.88 and 0.87 for L* and a*, respectively), when the sample moisture content decreased during heating.

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

    International Nuclear Information System (INIS)

    The present study was conducted to evaluate the combined effect of gamma irradiation in presence of ascorbic acid on the microbiological characteristics and thiobarbituric acid-reactive substances (TBARS) concentration of ground beef coated with an edible coating, crosslinked by gamma irradiation. The medium fat ground beef patties (23% fat ) were divided into two separate treatment groups: (i) control (ground beef without additive), (ii) ground beef with 0.5% (w/w) ascorbic acid. Meat samples were irradiated at doses of 0, 1, 2, and 3 kGy and stored at 4±2 deg. C. The content of TBARS was evaluated. After 7 days of storage, Enterobacteriaceae, presumptive Staphylococcus aureus, presumptive Pseudomonas spp., Brochothrix thermosphacta and lactic acid bacteria were enumerated. Results showed that lactic acid bacteria and Br. thermosphacta were more resistant to irradiation than Enterobacteriaceae and Pseudomonas. The content in TBARS was stabilized during post-irradiation storage for samples containing ascorbic acid. Shelf life extension periods estimated on the basis of a limit level of 6 log CFU/g for APCs were 4, 7, and 10 days for samples irradiated at 1, 2, and 3 kGy, respectively. However, the incorporation of ascorbic acid in ground beef did not improve significantly (p>0.05) the inhibitory effect of gamma irradiation

  12. Rapid and specific spectrophotometric and RP-HPLC methods for the determination of ascorbic acid in fruits juices and in human plasma

    International Nuclear Information System (INIS)

    Ascorbic acid (AA) is one of the most important water soluble vitamin in the human diet, present naturally in a wide range of foods, especially fruits and vegetables. The objective of this study was to develop a rapid, sensitive and specific method for the determination of ascorbic acid (vitamin C) from a variety of sources like fresh fruits or from human plasma using spectrophotometric technique or by RP-HPLC. Initially, estimation of vitamin C was carried out spectrophotometrically as UV spectroscopy is a trusted technique to monitor small quantities of drugs and vitamins. The assay was linear over the concentration range of 0.05-100 mi cro g/mL/sup -I/. In the second procedure, we attempted to separate and quantitate ascorbic acid from fruit juices as well as from human plasma by RP-HPLC with UV detection. This has been possible because of the diversity of columns and conditions of analysis available. Chromatographic separation was successfully achieved on a pre-packed Kromasil 100, C/sub 18/ (5 macro m 25 x 0.46) column using acetonitrile water (60:40; v/v) as mobile phase at a flow rate of 0.75 mL/sup -min/ and effluent monitored at 265 nm. The assay was also linear over the concentration range of 0.05-100 micro g/mL/sub -1/, with recovery ranging from 99.0-100.0 % and intra and inter day CV <3 % when applied to the analysis of ascorbic acid from fruit juice available in Pakistan at the time of study Grape fruit, malta, mosami, sweetlemon, fruiter, lemon, lime, cosami, sweetlemon, fruiter, lemon, lime, custard apple, orange, lemon, guava and papaya juice were found to be very rich in as ascorbic acid, while chikoo, pear, apricot, peach, carrot and some other fruits were found to be poor sources of ascorbic acid. (author)

  13. Inhibited acid descaling of boilers

    International Nuclear Information System (INIS)

    One of the most serious problem encountered steam generation is the formation of scale and sludge deposits on boiler heating surfaces. Detailed investigations were conducted to determine the factors that lead to these scales formation. Chemical analysis indicated the presence of calcium and magnesium salts, in the from of phosphates, sulphates, silicates and chlorides in addition to iron oxide (Fe2 O3). accelerated laboratory tests using accurate weight loss and gasometric measurements were conducted to select the most effective inhibitors for acid cleaning. The best cleaning results have been obtained after the application of: Ammonium bi fluoride 0.5% + HCl 7% + phenyl thiourea 0.5 Wt% at a temperature of 60 degree C followed by: Citric acid of 0.1 - 0.2% concentration about 38 blocked tubes by scale were found very clean after the acid descaling. Nitrogen-containing compounds, such as alkyl and amines, saturated and unsaturated nitrogen ring compounds, condensation products of amines (mainly aryl amines like aniline, toluidines, etc) with aldehydes (3,4) (mainly formaldehyde (5,6,7) and ketones. 3 fig

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

    Directory of Open Access Journals (Sweden)

    Rui Carlos Zambiazi

    2010-07-01

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

  15. [Effect of ascorbic acid and emoxypine on the dynamics of the quantitative roentgenological and clinical semiology parameters during infiltrative tuberculosis of lungs].

    Science.gov (United States)

    Novoselov, P N

    2009-01-01

    Prospective, placebo-controlled randomized investigation has been performed to evaluate the effect of ascorbic acid and emoxypine on the dynamics of changes in the roentgenological and clinical pattern during infiltrative tuberculosis of lungs in comparison to the rate of Micobacterium tuberculosis eradication during the standard chemotherapy. The results show that it is expedient to include these substances in the standard chemotherapy scheme. The administration of ascorbic acid and emoxypine during the first 10 days of the standard schedule ensures accelerated resolution of tubercular infitrates and increased rate of closing of the tuberculous disintegration cavities. The use ofemoxypine accelerates the eradication of M. tuberculosis. PMID:19928571

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

    OpenAIRE

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

    2013-01-01

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

  17. Micelle-mediated method for simultaneous determination of ascorbic acid and uric acid by differential pulse voltammetry

    Scientific Electronic Library Online (English)

    Alaécio P. dos, Reis; César R. T., Tarley; Lauro T., Kubota.

    1567-15-01

    Full Text Available O presente trabalho descreve uma metodologia analítica para determinação simultânea de ácido ascórbico (AA) e ácido úrico (AU) por voltametria de pulso diferencial empregando o surfactante catiônico cloreto de cetilpiridínio. Medidas voltamétricas de pulso diferencial realizadas em pH 7,0 revelaram [...] que o meio micelar catiônico permite separar em 282 mV os picos de oxidação de AA e AU na mesma solução, valor suficiente para determinar ambas as espécies simultaneamente. Como em pH 7,0 o AA está mais ionizado que o AU, sua atração eletrostática em direção às micelas catiônicas, formadas sobre a superfície do eletrodo de carbono vítreo, é maior; desta forma, promove a diminuição no sobrepotencial e o aumento na taxa de transferência de elétrons. Foram construídas curvas de calibração para AA e AU na faixa de concentração de 4,70 até 220 µmol L-1 e 0,50 até 110 µmol L-1. A metodologia proposta foi aplicada para a determinação de AA e AU em amostras de urina humana. Abstract in english The present work describes an analytical methodology for simultaneous determination of ascorbic acid (AA) and uric acid (UA) by differential pulse voltammetry employing the cationic surfactant, cetylpyridinium chloride. Differential pulse voltammetry measurements revealed that the cationic micellar [...] media may separate the oxidation peak potentials of AA and UA present in the same solution by about 282 mV, which is enough to determine both species simultaneously. As in pH 7.0 the AA is more ionized than UA, its electrostatic attraction towards the cationic micelles formed onto the surface of glassy carbon electrode is higher, therefore, promoting a decrease in the overpotential and increasing the electron transfer rate. Calibration curves to AA and UA in the concentration range from 4.70 up to 220 µmol L-1 and 0.50 up to 110 µmol L-1 were built. The proposed methodology was applied for the simultaneous determination of AA and UA in human urine samples.

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

    Directory of Open Access Journals (Sweden)

    Pavalee Chompoorat

    2013-10-01

    Full Text Available The effects of diacetyl tartaric acid ester of monoglycerides (DATEM, ascorbic acid (AA, urea, and dithiothreitol (DTT on viscoelastic properties of commercial hard red winter wheat gluten were investigated. A constant shear stress of 40 Pa was applied to gluten during creep-recovery test. Experimental creep-recovery compliance responses were fitted into a Burgers model with four elements accounting for characteristics of pure elastic (spring, viscoelastic (spring-dashpots elements, and viscous flow (dashpot. DATEM decreased the elasticity and viscoelasticity, but increased viscosity of gluten. The addition of AA, urea, and DTT, resulted in opposite rheological properties when compared with DATEM. Relationship among physical properties was also studied with principal component analysis (PCA including gluten viscoelasticity, dough mixing and baking properties. Regressed coefficients from Burgers model accounted for higher percent of explained variance and were independent from flour content, baking and dough mixing properties.

  19. Signal transduction mechanism for potentiation by ?1- and ?2-adrenoceptor agonists of L-ascorbic acid-induced DNA synthesis and proliferation in primary cultures of adult rat hepatocytes.

    Science.gov (United States)

    Moteki, Hajime; Kimura, Mitsutoshi; Sunaga, Katsuyoshi; Tsuda, Tadashi; Ogihara, Masahiko

    2013-01-30

    We investigated the effects of ?- and ?-adrenoceptor agonists on L-ascorbic acid-induced hepatocyte DNA synthesis and proliferation in primary cultures of adult rat hepatocytes. The results showed that phenylephrine (10(-6) M) and metaproterenol (10(-6) M) alone did not induce hepatocyte DNA synthesis and proliferation. However, when combined with L-ascorbic acid (10(-6) M), these adrenoceptor agonists potentiated the hepatocyte DNA synthesis and proliferation induced by L-ascorbic acid. Then intracellular signal transduction mechanisms for the effects of phenylephrine and metaproterenol on L-ascorbic acid-induced hepatocyte mitogenesis were examined. Western blot analysis showed that phenylephrine and metaproterenol did not potentiate L-ascorbic acid-induced insulin-like growth factor I receptor tyrosine kinase phosphorylation. In contrast, they both significantly potentiated L-ascorbic acid-induced extracellular-signal regulated kinase-2 (ERK2) phosphorylation within 5 min. Moreover, cell-permeable second messenger analogs phorbol ester (10(-7) M) and 8-bromo cAMP (10(-7) M) mimicked the effects of phenylephrine and metaproterenol on L-ascorbic acid-induced ERK2 phosphorylation. The effects of these adrenoceptor agents were specifically antagonized by GF109203X and H-89, respectively. These results indicate that activation of ERK2 via protein kinas C and protein kinase A represents a mechanism for potentiation of L-ascorbic acid-induced hepatocyte DNA synthesis and proliferation in primary cultures of adult rat hepatocytes. PMID:23270716

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

    Science.gov (United States)

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

    2014-09-01

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

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

    Scientific Electronic Library Online (English)

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

    2011-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Telma Elita Bertolin

    2011-12-01

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

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

    International Nuclear Information System (INIS)

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

  4. Fabrication of Poly(Aspartic Acid-Nanogold Modified Electrode and Its Application for Simultaneous Determination of Dopamine, Ascorbic Acid, and Uric Acid

    Directory of Open Access Journals (Sweden)

    Xiaoli Zhang

    2012-03-01

    Full Text Available A nanostructured polymer film incorporated gold nanoparticles modified electrode was fabricated. The fabrication process involved a previous electropolymerization of aspartic acid and followed by the eletrodeposition of gold nano-particles on the glassy carbon electrode. The resulting poly (aspartic acid-nanogold modified electrode (PAA- nano-Au/GCE was characterized by scanning electron microscopy (SEM and electrochemical impedance spectros-copy (EIS. A higher catalytic activity was obtained to electrocatalytic oxidation of dopamine (DA, ascorbic acid (AA and uric acid (UA due to the enhanced peak current and well-defined peak separations compared with three, bare GCE, PAA/GCE and nano-Au/GCE. Simultaneous determination of DA, AA, and UA were studied by voltammetry. The linear range of 5.0 × 10-7 - 1.0 × 10-4 M for DA, 5.0 × 10-6 - 2.0 × 10-3 M for AA and 5.0 × 10-6 - 1.0 × 10-3 M for UA was obtained. The detection limit was calculated for DA, AA and UA as being 6.5 × 10-8 M, 5.6 × 10-7 M and 3.0 × 10-7 M, respectively (S/N = 3. The practical application of the present modified electrode was demonstrated by the determination of DA, AA and UA in calf serum and fetal calf serum samples.

  5. Organochlorines inhibit acetaminophen glucuronidation by redirecting UDP-glucuronic acid towards the D-glucuronate pathway

    International Nuclear Information System (INIS)

    Industry-derived organochlorines are persistent environmental pollutants that are a continuing health concern. The effects of these compounds on drug metabolism are not well understood. In the current study we present evidence that the inhibition of acetaminophen (APAP) glucuronidation by minute concentrations of organochlorines correlates well with their ability to stimulate the D-glucuronate pathway leading to ascorbate synthesis. A set of 6 arylated organochlorines, including 5 PCB (polychlorinated biphenyl) congeners, were assessed for their effects on APAP glucuronidation in isolated hepatocytes from male Sprague-Dawley rats. The capacity of each organochlorine to inhibit APAP glucuronidation was found to be directly proportional to its capacity to stimulate ascorbate synthesis. PCB153, PCB28 and bis-(4-chlorophenyl sulfone) (BCPS) in increasing order were the most effective organochlorines for inhibiting APAP glucuronidation and stimulating the D-glucuronate pathway. None of the 3 inhibitors of APAP glucuronidation were able to alter the expression of UGT1A6, UGT1A7 and UGT1A8 (the major isoforms responsible for APAP glucuronidation in the rat), however, their efficacy at inhibiting APAP glucuronidation was proportional to their capacity to deplete UDP-glucuronic acid (UDPGA). BCPS-mediated inhibition of APAP glucuronidation in isolated hepatocytes had non-competitive characteristics and was insensitive to the inactivation of cytochrome P450. The effective organon of cytochrome P450. The effective organochlorines were also able to selectively stimulate the hydrolysis of UDPGA to UDP and glucuronate in isolated microsomes, but could not inhibit APAP glucuronidation in microsomes when UDPGA was in excess. We conclude that organochlorines are able to inhibit APAP glucuronidation in hepatocytes by depleting UDPGA via redirecting UDPGA towards the D-glucuronate pathway. Because the inhibition is non-competitive, low concentrations of these compounds could have long term inhibitory effects on the glucuronidating capacity of hepatocytes

  6. Understanding biocatalyst inhibition by carboxylic acids

    Directory of Open Access Journals (Sweden)

    LauraRJarboe

    2013-09-01

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

  7. Effect of antioxidant (alpha-tocopherol and ascorbic acid) fortification on light-induced flavor of milk.

    Science.gov (United States)

    van Aardt, M; Duncan, S E; Marcy, J E; Long, T E; O'Keefe, S F; Nielsen-Sims, S R

    2005-03-01

    The effectiveness of added antioxidants against oxidation off-flavor development in light-exposed milk was evaluated using sensory and chemical analysis. Sensory testing for similarity showed no perceivable difference between control milk and milk with added (1) 0.05% alpha-tocopherol (TOC) and (2) 0.025% alpha-tocopherol and 0.025% ascorbic acid (TOC/ASC), but did demonstrate a perceivable difference when adding (3) 0.05% ascorbic acid (ASC) alone. Subsequently, sensory testing for difference showed a significant difference in oxidation off-flavor between light-exposed control milk and light-exposed milk with added TOC/ASC, whereas milk fortified with TOC was not different from control. Gas chromatography-olfactometry showed that more aroma-active flavor compounds were observed in light-exposed milk treated with TOC and TOC/ASC than light-exposed milk with no added antioxidants. The thiobarbituric acid reactive substances (TBARS) test verified chemically the extent of oxidation in control and antioxidant-treated milk samples. Milk that was exposed to light for 10 h showed a significantly higher TBARS value (0.92 +/- 0.09 mg/kg) than milk that was protected from light (0.59 +/- 0.184 mg/kg), or milk that was treated with TOC/ASC (0.26 +/- 0.092 mg/kg). Direct addition of low levels of antioxidants (TOC/ASC) to milk protected its flavor over 10 h of light exposed storage. PMID:15738220

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

    Directory of Open Access Journals (Sweden)

    Liu X

    2014-02-01

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

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

    Scientific Electronic Library Online (English)

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

    2000-04-01

    Full Text Available Um sistema de análise por injeção em fluxo usando um eletrodo tubular baseado nas propriedades redox de íons cobre (II) oclusos em membrana de EVA foi desenvolvido para determinação de ácido L-ascórbico. A matriz de polietileno-co-vinil acetato (EVA 40% m/m) foi dopada com íons cobre (II) e dispersa [...] na superfície de um eletrodo tubular de grafite/epóxi. O eletrodo mostrou resposta super-Nernstiana para ácido L-ascórbico na faixa de concentração entre 10-3 - 10-1 mol L-1 com um limite de detecção de 8,5×10-4 mol L-1, quando 0,1 mol L-1 de tampão KH2PO4 misturado com 0,1 mol L-1 de peróxido de hidrogênio em pH 5,0 foi empregado como solução carregadora. O sistema FIA-potenciométrico permite uma freqüencia analítica de 120 amostras por hora com uma precisão de 3,6 %. Os resultados obtidos na determinação de ácido L-ascórbico em amostras farmacêuticas, sem qualquer tratamento prévio, pelo método proposto foram similares a aqueles obtidos pelo método da Farmacopéia Britânica. Abstract in english A flow injection system using a tubular electrode based on the redox properties of copper (II) ions occluded in EVA membrane was developed for L-ascorbic acid determination. The poly-ethylene-co-vinyl acetate (EVA 40% m/m) matrix was doped with copper (II) ions and dispersed on the surface of a grap [...] hite/epoxy tubular electrode. The electrode showed a super-Nernstian response for L-ascorbic acid concentration between 10-3 and 10-1 mol L-1 with a detection limit of 8.5×10-4 mol L-1, when 0.1 mol L-1 KH2PO4 buffer mixed with 0.1 mol L-1 hydrogen peroxide at pH 5.0 was employed as carrier. The Potentiometric-FIA system allows an analytical frequency of 120 samples per hour with a precision of 3.6%. The results obtained for ascorbic acid determination in pharmaceutical samples, without any previous treatment, were similar to those obtained by the British Pharmacopoeia method.

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

    OpenAIRE

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

    2009-01-01

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

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

    Scientific Electronic Library Online (English)

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

    2014-08-01

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

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

    Scientific Electronic Library Online (English)

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

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

  13. Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells

    Directory of Open Access Journals (Sweden)

    Duan Rui-Dong

    2009-12-01

    Full Text Available Abstract Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-?-boswellic acids (AKBA, a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health.

  14. Developmental Response of Euplectrus comstockii (Hymenoptera: Eulophidae) to Ascorbic Acid in the Diet of the Larval Host, Heliothis virescens (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Recent developments in genetic engineering has paved the way for researchers to produce crops of high nutritional and yield value, in addition to being resistant to diseases and pests. Ascorbic acid is one of the nutrients that researchers are trying to enhance in plants. Studies have shown that th...

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

    International Nuclear Information System (INIS)

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

  16. THE PERIPHERAL AND MICRO-ENVIRONMENT IMMUNE FUNCTION OF NEONATAL DAIRY CALVES FED BETA-GLUCAN WITH AND WITHOUT ASCORBIC ACID

    Science.gov (United States)

    Neonatal dairy calves undergo many natural and imposed stressors; an immune modulator would help alleviate the associated deleterious effects. Beta-glucan and ascorbic acid have been shown to modulate certain immune functions when fed orally. The objective of this study was to examine the innate im...

  17. Levels of b-carotene, ascorbic acid and total phenols in the pulp of five commercial varieties of mango (Mangifera indica L.)

    Science.gov (United States)

    Five varieties of mangoes from four countries were evaluated with multiple harvests over a year to compare the ß-carotene, total phenol, and ascorbic acid levels of the fruit pulp. Only soft fruit (0.5 to 1 N compression) with a minimum of 10% soluble solids were used for these measurements to minim...

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

    Directory of Open Access Journals (Sweden)

    Kishna Ram Genwa

    2013-06-01

    Full Text Available Photogalvanic cells are photoelectrochemical cells chargeable in light for solar energy conversion and storage. They may be energy source for the future, if their electrical performance is increased. In this study, a photosensitizer Lissamine green B, a reductant Ascorbic acid and a surfactant NaLS have been used in the photogalvanic cell. The generated photopotential and photocurrent are 850.0 mV and 375.0 ?A respectively. The conversion efficiency of the cell, fill factor and the cell performance were observed 1.0257%, 0.2598% and 170.0 minutes in dark respectively. The effects of different parameters on the electrical output of the photogalvanic cell were observed. A mechanism was proposed for the photogeneration of electrical energy.

  19. L-ascorbic acid losses in Kenyan vegetables during cooking as determined by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    N.M.N. Wekesa

    2001-06-01

    Full Text Available The loss of L-ascorbic acid (L-AA in 14 different cooked local vegetables found in Nairobi markets was determined by high performance liquid chromatography. The effect of quantity of water on the loss of L-AA during cooking was studied with cowpea leaves. It was found that more L-AA was lost when larger amount of water was used than when smaller amount was used. The effect of the sharpness of the knife on the loss of L-AA was studied with spinach. It was found that more loss of L-AA occurred when a blunt (edge thickness 0.08 cm knife was used for cutting the vegetables than when a sharp knife (edge thickness 0.04 cm was used during cooking. L-AA was also determined when vegetables were cooked in different size pieces (surface are >1 cm2

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

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    CC. Lima

    2009-11-01

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

  1. Determination of creatinine, uric and ascorbic acid in bovine milk and orange juice by hydrophilic interaction HPLC.

    Science.gov (United States)

    Zuo, Ruiting; Zhou, Si; Zuo, Yuegang; Deng, Yiwei

    2015-09-01

    Creatinine (Cr), uric (UA) and ascorbic acid (AA) are common constituents in human fluids. Their abnormal concentrations in human fluids are associated with various diseases. Thus, apart from the endogenous formation in human body, it is also important to examine their sources from food products. In this study, a rapid and accurate HILIC method was developed for simultaneous determination of Cr, UA and AA in bovine milk and orange juice. Milk samples were pretreated by protein precipitation, centrifugation and filtration, followed by HPLC separation and quantification using a Waters Spherisorb S5NH2 column. The developed method has been successfully applied to determine the concentration of UA, AA and Cr in milk and fruit juice samples. The milk samples tested were found to contain UA and creatinine in the concentration range of 24.1-86.0 and 5.07-11.2?gmL(-1), respectively. The orange juices contain AA over 212?gmL(-1). PMID:25842333

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

    Scientific Electronic Library Online (English)

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

    1195-12-01

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

  3. Differential pulse voltammetry detection of dopamine and ascorbic acid by permselective silica mesochannels vertically attached to the electrode surface.

    Science.gov (United States)

    Li, Wanzhen; Ding, Longhua; Wang, Qiaohong; Su, Bin

    2014-08-21

    A thin film consisting of highly ordered and vertically oriented silica mesochannels (SMCs) was prepared on the indium tin oxide (ITO) coated glass electrode surface by chronopotentiometry. The mesochannel has a uniform pore size of 2-3 nm in diameter and a positively charged surface due to grafted ammonium groups. The electrostatic and steric effects resulted from control of the surface charge and the ionic buffer concentration make the SMCs permselective, favoring the mass transport of oppositely charged species and repelling that of similarly charged ones. By using differential pulse voltammetry (DPV), the SMCs with this charge selectivity can be employed for permselective detection of ascorbic acid (AA) and dopamine (DA) that are oppositely charged compounds. The obtained linear detection range was 49-2651 ?M for AA and 20-226 ?M for DA, respectively. AA and DA in real samples were also determined by the SMC film modified electrode. PMID:24949496

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

    International Nuclear Information System (INIS)

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

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

    Scientific Electronic Library Online (English)

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

    2010-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Danieele Fabíola Pereira da Silva

    2010-06-01

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

  7. Detection of postharvest changes of ascorbic acid in fresh-cut melon, kiwi, and pineapple, by using a low cost telemetric system.

    Science.gov (United States)

    Barberis, Antonio; Fadda, Angela; Schirra, Mario; Bazzu, Gianfranco; Serra, Pier Andrea

    2012-12-01

    The present paper deals with a novel telemetric device combined with a carbon amperometric sensor system to determine postharvest changes of ascorbic acid (AA) in fresh-cut fruits, without displacing products out of the storage rooms. The investigation was performed on kiwi, pineapple and melon, subjected to minimal processing, packaging, cold storage, and simulated shelf life. Results demonstrated that AA content of fresh-cut fruits of all species declines differently during storage. Cold storage notably reduced the degradation rate of AA in comparison with samples stored at 20°C. The cold-chain interruption resulted in a sharp AA content reduction when the optimal storage condition was not rapidly replaced. Unpredicted results showed a high activity of oxidative enzymes, which prevented AA detection in melon samples. Our sensor system allowed us to demonstrate that both ascorbate peroxidase and ascorbate oxidase affected the oxidative stability and the nutritional quality of fresh cut melon fruits. PMID:22953893

  8. Serum protein, ascorbic acid & iron & tissue collagen in oral submucous fibrosis--a preliminary study.

    Science.gov (United States)

    Anuradha, C D; Devi, C S

    1993-06-01

    A study of 36 patients with oral submucous fibrosis, revealed that all patients had the habit of chewing betel nut, pan masala or the traditional mixture (betel nut, betel leaf and lime) suggesting a link between fibrosis and arecanut. There was an increase in the globulin fraction of protein and hence a decreased A/G ratio in these patients. There was a significant increase in total protein levels possibly due to the increase in globulin fractions and other serum proteins. Ascorbate and iron levels decreased perhaps because of their utilisation in collagen synthesis. The total tissue collagen content increased significantly in patients with advanced disease and, it increased with the progression of the disease leading to hypomobility of the tongue, lips, cheeks, soft palate and faucial pillars. PMID:8225452

  9. Comparative Transcriptome Analysis Reveals the Influence of Abscisic Acid on the Metabolism of Pigments, Ascorbic Acid and Folic Acid during Strawberry Fruit Ripening

    Science.gov (United States)

    Luo, Zisheng; Mou, Wangshu; Mao, Linchun; Ying, Tiejin

    2015-01-01

    A comprehensive investigation of abscisic acid (ABA) biosynthesis and its influence on other important phytochemicals is critical for understanding the versatile roles that ABA plays during strawberry fruit ripening. Using RNA-seq technology, we sampled strawberry fruit in response to ABA or nordihydroguaiaretic acid (NDGA; an ABA biosynthesis blocker) treatment during ripening and assessed the expression changes of genes involved in the metabolism of pigments, ascorbic acid (AsA) and folic acid in the receptacles. The transcriptome analysis identified a lot of genes differentially expressed in response to ABA or NDGA treatment. In particular, genes in the anthocyanin biosynthesis pathway were actively regulated by ABA, with the exception of the gene encoding cinnamate 4-hydroxylase. Chlorophyll degradation was accelerated by ABA mainly owing to the higher expression of gene encoding pheide a oxygenase. The decrease of ?-carotene content was accelerated by ABA treatment and delayed by NDGA. A high negative correlation rate was found between ABA and ?-carotene content, indicating the importance of the requirement for ABA synthesis during fruit ripening. In addition, evaluation on the folate biosynthetic pathway indicate that ABA might have minor function in this nutrient’s biosynthesis process, however, it might be involved in its homeostasis. Surprisingly, though AsA content accumulated during fruit ripening, expressions of genes involved in its biosynthesis in the receptacles were significantly lower in ABA-treated fruits. This transcriptome analysis expands our understanding of ABA’s role in phytochemical metabolism during strawberry fruit ripening and the regulatory mechanisms of ABA on these pathways were discussed. Our study provides a wealth of genetic information in the metabolism pathways and may be helpful for molecular manipulation in the future. PMID:26053069

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Christiane de Queiroz Pereira

    2008-12-01

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

  12. The electrochemical modification of clenbuterol for biosensors of dopamine, norepinephrine, adrenalin, ascorbic acid and uric acid at paraffin-impregnated graphite electrode.

    Science.gov (United States)

    Jin, Guan-Ping; Peng, Xia; Ding, Yan-Feng

    2008-12-01

    The electrochemical modification of clenbuterol (CLB) was studied at paraffin-impregnated graphite electrode (WGE) in two potential ranges of 0.0-1.6V and -1.2 to 1.2V. Various methods including X-ray photoelectron spectroscopy (XPS), UV-spectroelectrochemistry, infrared (IR) spectra and electrochemical techniques have been used to characterizing the modification. Clenbuterol can be modified at the electrode surface by carbon-nitrogen linkage or carbon-carbon linkage in 0.0-1.6V or -1.2 to 1.2V, respectively. The electrochemical behaviors of dopamine (DA), norepinephrine (NE), adrenalin (EP), ascorbic acid (AA) and uric acid (UA) were studied at clenbuterol-modified paraffin-impregnated graphite electrode (CLB/WGE), and it was found that all these compounds could be detected successfully. PMID:18672357

  13. Graphene-multiwall carbon nanotube-gold nanocluster composites modified electrode for the simultaneous determination of ascorbic acid, dopamine, and uric acid.

    Science.gov (United States)

    Liu, Xiaofang; Wei, Shaping; Chen, Shihong; Yuan, Dehua; Zhang, Wen

    2014-08-01

    In this paper, graphene-multiwall carbon nanotube-gold nanocluster (GP-MWCNT-AuNC) composites were synthesized and used as modifier to fabricate a sensor for simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The electrochemical behavior of the sensor was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The combination of GP, MWCNTs, and AuNCs endowed the electrode with a large surface area, good catalytic activity, and high selectivity and sensitivity. The linear response range for simultaneous detection of AA, DA, and UA at the sensor were 120-1,701, 2-213, and 0.7-88.3 ?M, correspondingly, and the detection limits were 40, 0.67, and 0.23 ?M (S/N=3), respectively. The proposed method offers a promise for simple, rapid, selective, and cost-effective analysis of small biomolecules. PMID:24853456

  14. An electrochemical sensor for simultaneous determination of ascorbic acid, dopamine, uric acid and tryptophan based on MWNTs bridged mesocellular graphene foam nanocomposite.

    Science.gov (United States)

    Li, Huixiang; Wang, Yi; Ye, Daixin; Luo, Juan; Su, Biquan; Zhang, Song; Kong, Jilie

    2014-09-01

    A multi-walled carbon nanotubes (MWNTs) bridged mesocellular graphene foam (MGF) nanocomposite (MWNTs/MGF) modified glassy carbon electrode was fabricated and successfully used for simultaneous determination of ascorbic acid (AA), dopamine (DA), uric acid (UA) and tryptophan (TRP). Comparing with pure MGF, MWNTs or MWNTs/GS (graphene sheets), MWNTs/MGF displayed higher catalytic activity and selectivity toward the oxidation of AA, DA, UA and TRP. Under the optimal conditions, MWCNs/MGF/GCE can simultaneously detect AA, DA, UA and TRP with high selectivity and sensitivity. The detection limits were 18.28 µmol L(-1), 0.06 µmol L(-1), 0.93 µmol L(-1) and 0.87 µmol L(-1), respectively. Moreover, the modified electrode exhibited excellent stability and reproducibility. PMID:24913885

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

    International Nuclear Information System (INIS)

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

  16. Simultaneous electrochemical determination of dopamine and ascorbic acid using AuNPs@polyaniline core-shell nanocomposites modified electrode.

    Science.gov (United States)

    Yang, Limin; Liu, Shufeng; Zhang, Qixiu; Li, Feng

    2012-01-30

    A simple and effective strategy was proposed for synthesis of AuNPs@polyaniline (AuNPs@PANI) core-shell nanocomposites. AuNPs@PANI nanocomposites were prepared by one-step chemical oxidative polymerization of aniline using chloroaurate acid as the oxidant and AuNPs as the seeds. The synthesized AuNPs@PANI nanocomposites were characterized with transmission electron microscope and UV-vis absorption spectra. Cyclic voltammetric experiments indicated that AuNPs@PANI nanocomposites showed excellent electroactivity in neutral and even alkaline solution. The obtained AuNPs@PANI nanocomposites-modified electrode was fabricated to simultaneously determine dopamine (DA) and ascorbic acid (AA) by differential pulse voltammetry. The separation between the two peak potentials of DA and AA oxidation is 236 mV. The catalytic peak currents were linearly with the concentrations of DA and AA in the range of 10-1700 and 20-1600 ?M with correlation coefficients of 0.9997 and 0.9998, respectively. The detection limits for DA and AA were 5 and 8 ?M, respectively. PMID:22284471

  17. The protective role of ascorbic acid (vitamin C) against chlorpyrifos-induced oxidative stress in Oreochromis niloticus.

    Science.gov (United States)

    Ozkan, Ferbal; Gündüz, Suna Gül; Berköz, Mehmet; Hunt, Arzu Ozlüer; Yal?n, Serap

    2012-06-01

    Ability of ascorbic acid (vitamin C) to attenuate oxidative damage was evaluated in liver and brain tissues of Oreochromis niloticus (O. niloticus) experimentally exposed to sublethal concentrations of chlorpyrifos (CPF). O. niloticus was exposed to sublethal concentrations of CPF at 12 ?g/L (CPF1) and 24 ?g/L (CPF2) for 96 h. The fish of vitamin C (Vit C) and CPF2 + Vit C groups were fed with Vit C supplemented diet (200 mg Vit C/100 g feed). A significant increase in thiobarbituric acid-reactive substances (TBARS) level (P fish although liver TBARS level was not changed compared to control group. This result showed that lipid peroxidation (LPO) was elevated in brain of fish exposed to CPF. Glutathione peroxidase (GSH-Px) activity in liver and brain tissues was significantly elevated (P fish by CPF2 concentration. Superoxide dismutase (SOD) activity was decreased in liver, but increased in brain by exposure to CPF1 and CPF2 concentrations. Levels of TBARS were increased in brain of CPF-treated animals, but tended to decrease by the effect of Vit C. Vit C treatment for CPF-intoxicated animals normalized the otherwise raised activities of GSH-Px, CAT, and SOD within normal limits. The results clearly indicate that exposure to CPF caused a dose-dependent increase in oxidative stress brain and to a lesser extend in liver of fish and the ability of Vit C to attenuate CPF-induced oxidative damage. PMID:21818541

  18. Electrochemical sensor based on carbon-supported NiCoO2 nanoparticles for selective detection of ascorbic acid.

    Science.gov (United States)

    Zhang, Xin; Yu, Sha; He, Wenya; Uyama, Hiroshi; Xie, Qianjie; Zhang, Lu; Yang, Fengchun

    2014-05-15

    An electrochemical sensor for selective detection of ascorbic acid (AA) in the presence of dopamine (DA) and uric acid (UA) was fabricated by modifying the glassy carbon electrode (GCE) with carbon-supported NiCoO2 (NiCoO2/C) nanoparticles. The electrochemical impedance spectroscopic (EIS) studies reveal the little charge transfer resistance for the modified electrode. The electrocatalytic activity of the modified electrode for the oxidation of AA was investigated. The current sensitivity of AA was enhanced to about five times upon modification. The voltammetric response of AA was well resolved from the responses of DA and UA, and the oxidation potential of AA was negatively shifted to -0.20 V. The biosensor tolerated a wide linear concentration range for AA, from 1.0 × 10(-5)M to 2.63 × 10(-3)M (R(2)=0.9929), with a detection limit of 0.5 ?M (S/N = 3). Our results demonstrate that the NiCoO2/C nanomaterials has excellent AA sensing capability, including a fast response time, high reproducibility and stability, with great promise in the quantification of AA in real samples. That makes it a unique electrochemical sensor for the detection of AA which is free from the interference of DA, UA and other interferents. PMID:24441542

  19. Ascorbic-acid-assisted growth of high quality M@ZnO: a growth mechanism and kinetics study

    Science.gov (United States)

    Yang, Yun; Han, Shuhua; Zhou, Guangju; Zhang, Lijie; Li, Xingliang; Zou, Chao; Huang, Shaoming

    2013-11-01

    We present a general route for synthesizing M@ZnO nanoparticles (NPs) by using ascorbic acid (AA) to induce deposition of ZnO on various shaped and structured cationic-surfactant-capped NP surfaces (noble, magnetic, semiconductor, rod-like, spherical, cubic, dendrite, alloy, core@shell). The results show that the complexing (AA and Zn2+) and cooperative effects (AA and CTAB) play important roles in the formation of polycrystalline ZnO shells. Besides, the growth kinetics of M@ZnO was systematically studied. It was found that the slow growth rate favors the successful formation of uniform core@ZnO NPs with relatively loose shells. An appropriate growth rate allows achieving high quality M@ZnO NPs with dense shells. However, very fast growth causes significant additional nucleation and the formation of pure ZnO NPs. This general method is suitable for preparing M@ZnO using seed NPs prepared in both water and organic phases. It might be an alternative route for functionalizing NPs for bioapplications (ZnO is biocompatible), modulating material properties as designed, or synthesizing template materials for building other nanostructures.We present a general route for synthesizing M@ZnO nanoparticles (NPs) by using ascorbic acid (AA) to induce deposition of ZnO on various shaped and structured cationic-surfactant-capped NP surfaces (noble, magnetic, semiconductor, rod-like, spherical, cubic, dendrite, alloy, core@shell). The results show that the complexing (AA and Zn2+) and cooperative effects (AA and CTAB) play important roles in the formation of polycrystalline ZnO shells. Besides, the growth kinetics of M@ZnO was systematically studied. It was found that the slow growth rate favors the successful formation of uniform core@ZnO NPs with relatively loose shells. An appropriate growth rate allows achieving high quality M@ZnO NPs with dense shells. However, very fast growth causes significant additional nucleation and the formation of pure ZnO NPs. This general method is suitable for preparing M@ZnO using seed NPs prepared in both water and organic phases. It might be an alternative route for functionalizing NPs for bioapplications (ZnO is biocompatible), modulating material properties as designed, or synthesizing template materials for building other nanostructures. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03934j

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    He Ping, E-mail: heping1971@yahoo.com.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Wang Wei; Du Licheng; Dong Faqin; Deng Yuequan; Zhang Tinghong [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China)

    2012-08-20

    Graphical abstract: A novel Cu-zeolite A/graphene-modified glassy carbon electrode was applied in the simultaneous electrochemical determination of dopamine (DA) and ascorbic acid (AA). The potential difference between the two oxidation peaks of DA and AA were over 200 mV. The electrocatalytic oxidation currents of DA were linearly related to the corresponding concentration in the range of 1.0 Multiplication-Sign 10{sup -7}-1.9 Multiplication-Sign 10{sup -5} M. Highlights: Black-Right-Pointing-Pointer Cu nanoparticles doped-zeolite A/graphene (CuZEA/RGO) modified electrode was prepared. Black-Right-Pointing-Pointer The composites of CuZEA/RGO were prepared via reduction of Cu{sup 2+} functionalized zeolite A and graphene oxide in one pot. Black-Right-Pointing-Pointer The modified electrode was presented for the simultaneous determination of DA and AA. Black-Right-Pointing-Pointer The proposed electrode showed a higher electrocatalytic performance. - Abstract: A novel Cu-zeolite A/graphene modified glassy carbon electrode for the simultaneous electrochemical determination of dopamine (DA) and ascorbic acid (AA) has been described. The Cu-zeolite A/graphene composites were prepared using Cu{sup 2+} functionalized zeolite A and graphene oxide as the precursor, and subsequently reduced by chemical agents. The composites were characterized by X-ray diffraction, Fourier transform infrared spectra and scanning electron microscopy. Based on the Cu-zeolite A/graphene-modified electrode, the potential difference between the oxidation peaks of DA and AA was over 200 mV, which was adequate for the simultaneous electrochemical determination of DA and AA. Also the proposed Cu-zeolite/graphene-modified electrode showed higher electrocatalytic performance than zeolite/graphene electrode or graphene-modified electrode. The electrocatalytic oxidation currents of DA and AA were linearly related to the corresponding concentration in the range of 1.0 Multiplication-Sign 10{sup -7}-1.9 Multiplication-Sign 10{sup -5} M for DA and 2.0 Multiplication-Sign 10{sup -5}-2.0 Multiplication-Sign 10{sup -4} M for AA. Detection limits (<{exclamation_point}- no-mfc ->S/N<{exclamation_point}- /no-mfc -> = 3) were estimated to be 4.1 Multiplication-Sign 10{sup -8} M for DA and 1.1 Multiplication-Sign 10{sup -5} M for AA, respectively.

  2. Electropolymerisation of L-arginine at carbon paste electrode and its application to the detection of dopamine, ascorbic and uric acid.

    Science.gov (United States)

    Chandrashekar, B N; Swamy, B E Kumara; Pandurangachar, M; Sathisha, T V; Sherigara, B S

    2011-11-01

    L-arginine was electropolymerised on a carbon paste electrode (CPE) to form the biopolymer by free radical formation in the electro oxidation process of the amino and carboxylic group containing compound by cyclic voltammetric technique. The modified electrode shows an excellent electrocatalytic activity towards the oxidation of both dopamine (DA) and ascorbic acid (AA). It was demonstrated that the deposited biopolymer has positive charges over the bare carbon electrode surface, which leads to the formation of electrical double layer made the fast electron transfer process could leads to the diffusion of dopamine, ascorbic acid and uric acid on their charge gradient by cyclic voltammetric technique. The response of the sensor was tested towards the different dopamine concentration. The catalytic peak current obtained was linearly related to DA concentrations in the ranges of 5×10(-5) to 1×10(-4)M L(-1) with correlation co-efficient of 0.9924 which reveals the adsorption controlled process. The detection limit for dopamine was 5×10(-7)M L(-1). The interference studies showed that the modified electrode exhibits excellent selectivity in the presence of large excess of ascorbic acid (AA) and response is fast stable, reliable, resistant to biofouling and can be applied for the real sample analysis in medical, pharmaceutical and biotechnological sectors. The adsorption-controlled process and kinetic parameters of the poly(L-arginine) were determined using electrochemical approaches. PMID:21816583

  3. AN AUTOMATED METHOD FOR DETERMINATION OF ASCORBIC ACID IN URINE BY FLOW INJECTION CHEMILUMINESCENCE COUPLING WITH ON-LINE REMOVAL OF INTERFERENCE

    Scientific Electronic Library Online (English)

    LONGFEI, CAI; CHUNXIU, XU.

    2011-12-01

    Full Text Available A simple and automated method for determination of ascorbic acid (AA) in complex samples by flow injection chemiluminescence (FI-CL) was presented. It is based on the inhibitory effect of ascorbic acid on the chemiluminescence reaction between luminol and hydrogen peroxide in the flow system. A home [...] -made micro column of cation exchange resin was adapted to the FI manifold to achieve on-line removal of interference. This method was used to determine the AA content in urine samples with a detection limit of 6.03 x10(9) mol/L AA and recovery of 93.1-111.0%. This proposed method allows high - throughput determination of AA in urine samples without chromatographic separation, demonstrating that the FI-CL method has significant potential in determination of species in complex samples by adapting a micro column filled with various functionalized materials to the FI manifold.

  4. Ferrocene adsorbed into the porous octakis(hydridodimethylsiloxy)silsesquioxane after thermolysis in tetrahydrofuran media: An applied surface for ascorbic acid determination

    International Nuclear Information System (INIS)

    Highlights: ? Octakis(hydridodimethylsiloxi)silsesquioxane was synthesized and Ferrocene was adsorbed. ? Polymeric net through electrostatic interactions was observed. ? The novel materials presents electroacatalytic activity for Ascorbic acid. -- Abstract: Octakis(hydridodimethylsiloxi)silsesquioxane (Q8M8H) was synthesized and Ferrocene was adsorbed in a polymeric net through electrostatic interactions, with anion forming after the cleavage of any siloxy groups (ESFc). The nanostructured materials (Q8M8H and EsFc) were characterized by Fourier transform infrared spectra (FT-IR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), Thermogravimetric analyses and Voltammetric technique The cyclic voltammograms of the graphite paste electrode modified with ESFc showed one redox couple with E0? = 0.320 V (1.0 mol L?1 NaCl, v = 50 mV s?1), with a diffusion-controlled process and the redox process shows electrocatalytic activity for the oxidation of ascorbic acid.

  5. Phosphonoacetic Acid Inhibition of Frog Virus 3 Replication

    OpenAIRE

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

    1980-01-01

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

  6. Optimization of methodology to analyze ascorbic and dehydroascorbic acid in vegetables

    OpenAIRE

    Flávia Milagres Campos; Sônia Machado Rocha Ribeiro; Ceres M. Della Lucia; Helena Maria Pinheiro-Sant'Ana; Paulo César Stringheta

    2009-01-01

    In this study, different solutions to extract vitamin C were tested. High-performance liquid chromatography was chosen and the conditions were based on isocratic elution in reverse phase column. Dehydroascorbic acid was determined indirectly after its reduction using dithiothreitol. The use of metaphosphoric acid to stabilize the vitamin C was shown to be required and it was necessary to neutralize the pH of the extract to apply dithiothreitol. The average recovery was 90% in collard and toma...

  7. Efficient Synthesis of Suitably Protected ?-Difluoroalanine and ?-Difluorothreonine from L-Ascorbic Acid

    OpenAIRE

    Li, Gongyong; van der Donk, Wilfred A.

    2007-01-01

    Fluorinated amino acids are useful building blocks for the preparation of biologically active peptides and peptidomimetics with increased metabolic stability. We report here the synthesis of two fluorinated amino acids, ?-difluoroalanine and ?-difluorothreonine as analogs of Ser and Thr, respectively. These compounds were suitably protected for Fmoc-based solid phase peptide synthesis. Once incorporated into peptides, they may serve as alternative substrates or inhibitors of lantibiotic syn...

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

    OpenAIRE

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

    2012-01-01

    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 thi...

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

    Directory of Open Access Journals (Sweden)

    García-Bailo Bibiana

    2012-11-01

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

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

    OpenAIRE

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

    2007-01-01

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

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

    International Nuclear Information System (INIS)

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

  12. The Effect of Crude Oil Spill on the Ascorbic Acid Content of Some Selected Vegetable Species: Spinacea oleraceae, Solanum melongena and Talinum triangulare in an Oil Polluted Soil

    OpenAIRE

    Nwaoguikpe Reginald Nwazue

    2011-01-01

    The research work focused on the effect of oil spill on some certain soil physicochemical parameters and the concentrations of vitamin C (Ascorbic acid) of three leafy vegetable species at pre and post pollution periods. The vegetable species involved in the study included: Spinacea oleraceae (Spinach), Solanum melongena (Eggplant) and Talinum triangulare (Water leaf) in an oil polluted soil. The ascorbic acid contents of the species pre and post pollution periods expressed in mg/100 g of sam...

  13. A Comparative Assessment of the Proximate Composition, Ascorbic Acid and Heavy Metal Content of Two Species of Garden Egg (Solanum gilo and Solanum aubergine)

    OpenAIRE

    Edem; Christopher A.; Dosunmu; Miranda I.; Bassey; Francisca I.; Wilson; Charles; Umoren; Patience

    2009-01-01

    The proximate composition ,ascorbic acid and Heavy metal contents of two species of Garden egg, Solanum gilo and Solanum aubergine were evaluated using chemical analysis. The result of the proximate composition analysis showed that solanum gilo fruits had the following composition:moisture (74.80%), carbohydrate (52.13%), crude protein (14.87%), crude fibre (16%), crude fat (7%) and ash (10%). It also contained (93.7%) of ascorbic acid. The Solanum aubergine fruits on the other hand contained...

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

    International Nuclear Information System (INIS)

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

  15. Electrochemistry behavior of adrenalin, serotonin and ascorbic acid at novel poly rutin modified paraffin-impregnated graphite electrode

    International Nuclear Information System (INIS)

    A novel poly rutin (Ru) modified paraffin-impregnated graphite electrode (WGE) was fabricated by electrochemical method. The field emission scanning electron microscope (FE-SEM), infrared spectra (IR), in situ UV-spectroelectrochemical and electrochemical techniques proved the immobilization of rutin on WGE. Ru undergoes electrochemical oxidation in two ways related to the two catechol hydroxyl groups and the other two hydroxyl groups; the former not only carries out a two-electron two-proton reversible reaction, but also produces unstable phenoxy radicals which readily polymerize to strongly adhere to WGE surface companying Ru monomer embeded and adsorbed in the film (Ru/WGE). The Ru/WGE displayed strong catalytic function for the oxidation of adrenalin (EP), serotonin (5-HT), and ascorbic acid (AA) and resolved the overlap voltammetric response of EP and AA into two well-defined voltammetric peaks of about 172 mV with DPV. A linear response in the range of 3.0-90.0 ?M with detection limit (s/n = 3) of 8.0 x 10-7 M for EP was obtained in coexistence of AA (0.01 mM)

  16. Increasing tolerance to ozone by elevating foliar ascorbic acid confers greater protection against ozone than increasing avoidance.

    Science.gov (United States)

    Chen, Zhong; Gallie, Daniel R

    2005-07-01

    Ascorbic acid (Asc) is the most abundant antioxidant in plants and serves as a major contributor to the cell redox state. Exposure to environmental ozone can cause significant damage to plants by imposing conditions of oxidative stress. We examined whether increasing the level of Asc through enhanced Asc recycling would limit the deleterious effects of environmental oxidative stress. Plants overexpressing dehydroascorbate reductase (DHAR), which results in an increase in the endogenous level of Asc, were exposed to acute or chronic levels of ozone. DHAR-overexpressing plants had a lower oxidative load, a lower level of oxidative-related enzyme activities, a higher level of chlorophyll, and a higher level of photosynthetic activity 24 h following an acute exposure (2 h) to 200 ppb ozone than control plants, despite exhibiting a larger stomatal area. Reducing the size of the Asc pool size through suppression of DHAR expression had the opposite effect. Following a chronic exposure (30 d) to 100 ppb ozone, plants with a larger Asc pool size maintained a larger stomatal area and a higher oxidative load, but retained a higher level of photosynthetic activity than control plants, whereas plants suppressed for DHAR had a substantially reduced stomatal area, but also a substantially lower level of photosynthetic activity. Together, these data indicate that, despite a reduced ability to respond to ozone through stomatal closure, increasing the level of Asc through enhanced Asc recycling provided greater protection against oxidative damage than reducing stomatal area. PMID:15951482

  17. A highly selective and instantaneous nanoprobe for detection and imaging of ascorbic acid in living cells and in vivo.

    Science.gov (United States)

    Li, Na; Li, Yanhua; Han, Yaoyao; Pan, Wei; Zhang, Tingting; Tang, Bo

    2014-04-15

    The development of a specific reaction of nanomaterials and reactive species is of fundamental importance for the determination of biomolecules. Here we report a novel nanoprobe for detection and imaging of ascorbic acid (AA) in living cells and in vivo based on the specific reaction of cobalt oxyhydroxide (CoOOH) and AA. Persistent luminescence nanoparticles (PLNPs) were used as the luminescence unit, and CoOOH nanoflakes served as the quencher. When CoOOH was modified on the surface of the PLNPs, the luminescence of the PLNPs was efficiently quenched by the CoOOH. In the presence of AA, CoOOH was reduced to Co(2+) and the luminescence of PLNPs was restored. The nanoprobe showed high selectivity and an instantaneous response. The luminescence property permits detection and imaging without external excitation, which could effectively avoid background noise and scattering of light from biological matrixes produced by in situ excitation. The current strategy provides an effective platform for monitoring and imaging reactive species in living cells and in vivo. PMID:24654795

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Science.gov (United States)

    He, Ping; Wang, Wei; Du, Licheng; Dong, Faqin; Deng, Yuequan; Zhang, Tinghong

    2012-08-20

    A novel Cu-zeolite A/graphene modified glassy carbon electrode for the simultaneous electrochemical determination of dopamine (DA) and ascorbic acid (AA) has been described. The Cu-zeolite A/graphene composites were prepared using Cu(2+) functionalized zeolite A and graphene oxide as the precursor, and subsequently reduced by chemical agents. The composites were characterized by X-ray diffraction, Fourier transform infrared spectra and scanning electron microscopy. Based on the Cu-zeolite A/graphene-modified electrode, the potential difference between the oxidation peaks of DA and AA was over 200mV, which was adequate for the simultaneous electrochemical determination of DA and AA. Also the proposed Cu-zeolite/graphene-modified electrode showed higher electrocatalytic performance than zeolite/graphene electrode or graphene-modified electrode. The electrocatalytic oxidation currents of DA and AA were linearly related to the corresponding concentration in the range of 1.0×10(-7)-1.9×10(-5)M for DA and 2.0×10(-5)-2.0×10(-4)M for AA. Detection limits (S/N=3) were estimated to be 4.1×10(-8)M for DA and 1.1×10(-5)M for AA, respectively. PMID:22819046

  1. Synthesis of Pt/ionic liquid/graphene nanocomposite and its simultaneous determination of ascorbic acid and dopamine.

    Science.gov (United States)

    Li, Fenghua; Chai, Jia; Yang, Huafeng; Han, Dongxue; Niu, Li

    2010-05-15

    A water-soluble and electroactive composite - Pt nanoparticles/polyelectrolyte-functionalized ionic liquid (PFIL)/graphene sheets (GS) nanocomposite was synthesized in one pot. The structure and composition of the Pt/PFIL/GS nanocomposite were studied by means of ultraviolet-visible (UV-vis) and X-ray photoelectron spectra (XPS). Scanning electron microscopy (SEM) and transmission electron microscope (TEM) images reveal Pt nanoparticles are densely dispersed on the transparent thin PFIL-functionalized graphene sheets. The obtained Pt/PFIL/GS nanocomposite-modified electrode was fabricated to simultaneously determine ascorbic acid (AA) and dopamine (DA) by cyclic voltammetry. It is worthwhile noting that the difference between the two peak potentials of AA and DA oxidation is over 200mV, which leads to distinguishing AA from DA. The detection of increasing concentrations of AA in the presence of DA and the oxidation of continuous addition of DA in the presence of AA were also studied using differential pulse voltammetry. The proposed sensor in real sample analysis was also examined in human urine samples. Three independent oxidation peaks appear in urine sample containing AA and DA. Therefore, the Pt/PFIL/GS nanocomposite might offer a good possibility for applying it to routine analysis of AA and DA in clinical use. PMID:20298894

  2. Cheap and easy modification of glassy carbon electrode for voltammetric determination of dopamine in the presence of ascorbic acid

    Directory of Open Access Journals (Sweden)

    A Naseri

    2011-10-01

    Full Text Available Background and the purpose of the study: Different methods have been proposed to modify glassy carbon electrode in order to determine dopamine (DA, as one of the most important neurotransmitters in central nervous systems of mammalian. These methods are time comsuming and in some cases expensive. In this work, a very simple and cheap pretreatment method is developed for the bare glassy carbon electrode (GCE to determine DA in the presence of Ascorbic acid (AA.   Methods: Cyclic voltammetry as an electrochemical activation procedure was used for activation of glassy carbon electrode in order to separate diffrential pulse peaks of DA and AA. The effect of different parameters such as pH for supporting electrolyte, range of potential and the number of cycles were investigated. Finally, differential pulse voltammetry was used to determine DA in the presence of AA. Results: On the activated electrode under optimum condition, anodic peak of AA shifted to negative potentials and peak current decreased, but the peak current of DA increased. The peak current was linearly proportional to the bulk concentration of DA in the range of 6.5×10-7- 1.8×10-5 mol l-1. The limit of detection was 6.2×10-7 mol l-1. Conclusion: A simple and cheap method was developed for the activation of glassy carbon electrode. It was possible to determine DA in the presence of AA on the treated electrode. The proposed method was used to determine DA in pharmacutical samples.      

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

    Directory of Open Access Journals (Sweden)

    Jianqing Zhou

    2013-10-01

    Full Text Available A novel glassy carbon electrode (GCE modi?ed with carbon-spheres has been fabricated through a simple casting procedure. The modified GCE displays high selectivity and excellent electrochemical catalytic activities towards dopamine (DA, serotonin (5-HT, and ascorbic acid (AA. In the co-existence system, the peak separations between AA and DA, DA and 5-HT, and AA and 5-HT are large up to 230, 180, and 410 mV, respectively. Differential pulse voltammetry (DPV has been employed to simultaneously detect DA, 5-HT, and AA, and the linear calibration curves for DA, 5-HT, and AA are obtained in the range of 20.0–150.0 ?M, 40.0–750.0 ?M and 300.0–2,000.0 ?M with detection limits (S/N = 3 of 2.0 ?M, 0.7 ?M and 0.6 ?M, respectively. The proposed electrode has been applied to detect DA, 5-HT, and AA in real samples using standard addition method with satisfactory results.

  4. Selective Determination of Epinephrine in the Presence of Ascorbic Acid and Dopamine Using a Glassy Carbon Electrode Modified with Valine

    Directory of Open Access Journals (Sweden)

    Xia Li

    2010-01-01

    Full Text Available A glassy carbon electrode (GCE modified with valine was used for the sensitive volt metric determination ofepinephrine (EP. The electrochemical response characteristics of the modified electrode toward EP, ascorbic acid (AAand dopamine (DA were investigated by cyclic voltammetry (CV. The results show an efficient catalytic activity ofthe electrode for the electro-oxidation of EP, which leads to an improvement to the reversibility of the electroderesponse. The effect of pH and potential sweep rate on the mechanism of the electrode process was investigated. Themodified electrode exhibits an efficient electron mediating behavior along with well-separated oxidation peaks for EP,AA, and DA. Under the optimum pH of 7.0 in phosphate buffer solution(PBS, the CV anodic peak current showed alinear relation versus EP concentration in the range of 4.5×10-6~1.0×10-5mol·L-1 and 1.0×10-5~1.4×10-4 mol·L-1, withcorrelation coefficients of 0.9997 and 0.9942. The detection limit is 7.6×10-7 mol·L-1. High sensitivity and selectivity,submicromolar detection limit, high reproducibility, along with ease of preparation and regeneration of the electrodesurface by simple polishing make this method suitable for the determination of EP in pharmaceutical and clinicalpreparations.

  5. Highly sensitive and selective electrochemical determination of dopamine and ascorbic acid at Ag/Ag2S modified electrode

    International Nuclear Information System (INIS)

    A biosensor electrode possessing highly sensitive and selective determination of dopamine (DA) is fabricated. This electrode, a silver (Ag) thin film on indium-tin-oxide glass, is treated with a silver sulfide (Ag2S) film using electrochemical deposition. Active Ag ion is easier to form on Ag2S than on pristine Ag, which prefers to attract ascorbic acid (AA). The Ag2S layer reduces the oxidation potential of AA due to the electrostatic interaction, which results in well-separation of mixed oxidation responses to both of DA and AA. Besides, the Ag2S-modified electrode exhibits dramatic electrocatalytic effect on the oxidation of DA in the presence of AA. In 0.1 M phosphate buffer solution at pH ? 7.0, the differential pulse voltammetric peak intensity linearly correlates with DA concentration in two regions, viz. 1.0-10, and 10-100 ?M, with correlation coefficient of 0.998 and 0.995, respectively. The lowest concentration limit of 1.0 ?M DA can be detected. The interference of AA effectively diminishes in the mixed solution. These features make the Ag2S significant for selective and sensitive measurement of DA in the presence of excess AA.

  6. Simultaneous determination of dopamine, sertonin and ascorbic acid at a glassy carbon electrode modified with carbon-spheres.

    Science.gov (United States)

    Zhou, Jianqing; Sheng, Meili; Jiang, Xueyue; Wu, Guozhi; Gao, Feng

    2013-01-01

    A novel glassy carbon electrode (GCE) modi?ed with carbon-spheres has been fabricated through a simple casting procedure. The modified GCE displays high selectivity and excellent electrochemical catalytic activities towards dopamine (DA), serotonin (5-HT), and ascorbic acid (AA). In the co-existence system, the peak separations between AA and DA, DA and 5-HT, and AA and 5-HT are large up to 230, 180, and 410 mV, respectively. Differential pulse voltammetry (DPV) has been employed to simultaneously detect DA, 5-HT, and AA, and the linear calibration curves for DA, 5-HT, and AA are obtained in the range of 20.0-150.0 ?M, 40.0-750.0 ?M and 300.0-2,000.0 ?M with detection limits (S/N = 3) of 2.0 ?M, 0.7 ?M and 0.6 ?M, respectively. The proposed electrode has been applied to detect DA, 5-HT, and AA in real samples using standard addition method with satisfactory results. PMID:24135993

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Ekasith Somsook

    2011-10-01

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

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

    Science.gov (United States)

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

    2015-06-15

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

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

    Directory of Open Access Journals (Sweden)

    Edson José Fragiorge

    2007-03-01

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

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

    Scientific Electronic Library Online (English)

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

    2007-03-01

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

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

    Scientific Electronic Library Online (English)

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

    Full Text Available Simple, rapid and precise amperometric methods for quantification of ascorbic acid (AA) are presented. Glassy carbon (GC), carbon paste (CP) and modified carbon paste (MCP) electrodes are used for this purpose. MCP electrodes are of CP with 10 % vanadate (V). All electrodes are inserted in a wall-je [...] t device with an Ag/AgCl reference electrode and a platinum auxiliary electrode. This device is coupled to a flow injection analysis (FIA) set-up. Hydrodynamic and amperometric parameters are optimized unvaryingly. GC electrodes present slopes of 4.75 ´ 10(5) nA L mol-1 (± 6.4 %) under optimum conditions. CP and MCP electrodes show higher sensitivity, with slopes of 6.37 ´ 10(5) nA L mol-1 (± 6.6 %) and 7.32 ´ 10(5) nA L mol-1 (± 4.4 %). Linear responses range (1.0-2.0) ´ 10-6 to (0.8-1.0) ´ 10-5 mol L-1. Correlation coefficients were > 0.994 and about 48 samples are analysed per hour. Application of the proposed method to the analysis of soft drinks is presented.

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

    Directory of Open Access Journals (Sweden)

    M. Goreti F. Sales

    2008-01-01

    Full Text Available Simple, rapid and precise amperometric methods for quantification of ascorbic acid (AA are presented. Glassy carbon (GC, carbon paste (CP and modified carbon paste (MCP electrodes are used for this purpose. MCP electrodes are of CP with 10 % vanadate (V. All electrodes are inserted in a wall-jet device with an Ag/AgCl reference electrode and a platinum auxiliary electrode. This device is coupled to a flow injection analysis (FIA set-up. Hydrodynamic and amperometric parameters are optimized unvaryingly. GC electrodes present slopes of 4.75 ´ 10(5 nA L mol-1 (± 6.4 % under optimum conditions. CP and MCP electrodes show higher sensitivity, with slopes of 6.37 ´ 10(5 nA L mol-1 (± 6.6 % and 7.32 ´ 10(5 nA L mol-1 (± 4.4 %. Linear responses range (1.0-2.0 ´ 10-6 to (0.8-1.0 ´ 10-5 mol L-1. Correlation coefficients were > 0.994 and about 48 samples are analysed per hour. Application of the proposed method to the analysis of soft drinks is presented.

  14. Collagen synthesis promoting pullulan-PEI-ascorbic acid conjugate as an efficient anti-cancer gene delivery vector.

    Science.gov (United States)

    Ambattu, Lizebona August; Rekha, M R

    2015-08-01

    Cationized pullulan (pullulan-PEI; PP) was synthesized and further modified with an anti-oxidant molecule, ascorbic acid (PPAA) at various ratios. The nanoplexes formed at an optimum ratio of 4:1 was within a size of 150nm and had a zeta potential of 9-14mV. The nanoplexes at this ratio was used for further investigations. The cell internalization and transfection efficiency of these nanoplexes were determined in presence of serum. The internalization and transfection efficiency were found to be unaffected by the presence of fetal bovine serum. Another interesting observation was that this polymer was found to have collagen synthesis promoting property. The collagen synthesis effect of these polymers was quantified and observed that PPAA3 promoted the highest. Transfection efficiency was evaluated by assessing the p53 gene expression in C6 rat glioma cells and cell death was quantified to be 96% by flow cytometry, thus establishing the high efficacy of this polymer. PMID:25933522

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-15

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

  16. One-pot syntheses of Li3V2(PO4)3/C cathode material for lithium ion batteries via ascorbic acid reduction approach

    International Nuclear Information System (INIS)

    Highlights: ? Ascorbic acid (C6H8O6) was used as reducing agent and organic carbon source. ? The strategy shortened the period of material preparation and lowered energy cost. ? Li3V2(PO4)3/C was obtained with enhanced electrochemical performance. ? Effects of reagents on electrochemical performance of Li3V2(PO4)3 were evaluated. - Abstract: Monoclinic Li3V2(PO4)3/C composite synthesized by ascorbic acid reduction method is examined as a cathode material for Li-ion batteries. Transmission electron microscopy (TEM) images show that the nano-size particles are obtained. The reversible capacity of Li3V2(PO4)3/C prepared with LiOH and H3PO4 is 141.2 mAh g-1 after 100 cycles at 1C discharge rate between 3 V and 4.8 V, and the retention rates of discharge capacity is 93.4%. Ascorbic acid plays not only as reduction reagent, but also as carbon sources. This strategy shortens the time of solid state reaction and facilitates the procedure of synthesis. Effects of different precursors materials on the performance of the Li3V2(PO4)3/C are investigated.

  17. Application of bone marrow and adipose-derived mesenchymal stem cells for testing the biocompatibility of metal-based biomaterials functionalized with ascorbic acid.

    Science.gov (United States)

    Marycz, Krzysztof; ?mieszek, Agnieszka; Grzesiak, Jakub; Donesz-Sikorska, Anna; Krzak-Ro?, Justyna

    2013-12-01

    In this study, metal-based biomaterials were functionalized with ascorbic acid (LAA). Two types of substrates were used: austenitic steel 316L and titanium Ti6Al4V. Coatings were prepared with the sol-gel method and applied on metal surfaces using the dip-coating technique. Ascorbic acid was delivered with SiO2-coating at concentrations of 0.1 and 0.4 M. The morphology of the surfaces and coatings was determined using scanning electron microscope (SEM), whereas their elemental composition by SEM-EDX. Immobilization of ascorbic acid in the coatings was confirmed with Raman spectroscopy. The biocompatibility of the materials obtained was tested in vitro using both bone marrow- and adipose-derived mesenchymal stem cells (BMMSC and ADMSC, respectively). Proliferation rate and morphology of cells cultured in the presence of designed biomaterials were monitored after 24, 48, 120 and 168 h of propagation. The results obtained indicated that silica coatings doped with 0.4 M LAA had a positive effect on the proliferation rate of investigated cells, and in some cases on the growth pattern of culture. PMID:24280658

  18. A dual-template imprinted polymer-modified carbon ceramic electrode for ultra trace simultaneous analysis of ascorbic acid and dopamine.

    Science.gov (United States)

    Bali Prasad, Bhim; Jauhari, Darshika; Tiwari, Mahavir Prasad

    2013-12-15

    A dual-template imprinted polymer film containing dispersed multiwalled carbon nanotubes was exploited in the fabrication of a typical, reproducible, and rugged carbon ceramic electrode, adopting "surface grafting from" approach for the growth of a nanometer thin coating on its surface. For this, chloro groups were first introduced at the exterior surface of silica-carbon composite electrode through sol-gel modification using (3-chloropropyl)-trimethoxysilane, followed by an iniferter (sodium diethyl dithiocarbamate) initiated photopolymerization of functional monomer (2,4,6-trisacrylamido-1,3,5-triazine), mixed templates (ascorbic acid and dopamine), and cross-linker (ethylene glycol dimethacrylate), in the presence of multiwalled carbon nanotubes. The modified sensor was validated for the simultaneous analysis of ascorbic acid and dopamine in aqueous, blood serum, cerebrospinal fluid, and pharmaceutical samples, using differential pulse anodic stripping voltammetric technique. The oxidation peak potentials for both analytes were found to be well apart approximately by 300 mV, which was large enough to allow selective and sensitive analysis of one in the presence of other, without any cross reactivity, interferences and false-positives. The detection limits realized by the proposed sensor, under optimized conditions, were found to be as low as 2.24 ng mL(-1) for ascorbic acid and 0.21 ng mL(-1) for dopamine (S/N=3). Such stringent limits could be considered suitable for the primitive diagnosis of several chronic diseases, in clinical settings. PMID:23831643

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  1. Optimization of methodology to analyze ascorbic and dehydroascorbic acid in vegetables

    Directory of Open Access Journals (Sweden)

    Flávia Milagres Campos

    2009-01-01

    Full Text Available In this study, different solutions to extract vitamin C were tested. High-performance liquid chromatography was chosen and the conditions were based on isocratic elution in reverse phase column. Dehydroascorbic acid was determined indirectly after its reduction using dithiothreitol. The use of metaphosphoric acid to stabilize the vitamin C was shown to be required and it was necessary to neutralize the pH of the extract to apply dithiothreitol. The average recovery was 90% in collard and tomato samples. The presence of oil did not interfere in extraction and the methodology can be used to analyze stir fried vegetables.

  2. Optimization of methodology to analyze ascorbic and dehydroascorbic acid in vegetables

    Scientific Electronic Library Online (English)

    Flávia Milagres, Campos; Sônia Machado Rocha, Ribeiro; Ceres M., Della Lucia; Helena Maria, Pinheiro-Sant' Ana; Paulo César, Stringheta.

    Full Text Available In this study, different solutions to extract vitamin C were tested. High-performance liquid chromatography was chosen and the conditions were based on isocratic elution in reverse phase column. Dehydroascorbic acid was determined indirectly after its reduction using dithiothreitol. The use of metap [...] hosphoric acid to stabilize the vitamin C was shown to be required and it was necessary to neutralize the pH of the extract to apply dithiothreitol. The average recovery was 90% in collard and tomato samples. The presence of oil did not interfere in extraction and the methodology can be used to analyze stir fried vegetables.

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

    International Nuclear Information System (INIS)

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

  4. Bacterial Production of d-Erythroascorbic Acid and l-Ascorbic Acid through Functional Expression of Saccharomyces cerevisiae d-Arabinono-1,4-Lactone Oxidase in Escherichia coli

    OpenAIRE

    Lee, Byung-Hoon; Huh, Won-Ki; Kim, Seong-tae; Lee, Jung-Shin; Kang, Sa-Ouk

    1999-01-01

    d-Arabinono-1,4-lactone oxidase, which catalyzes the terminal step in the biosynthesis of d-erythroascorbic acid in Saccharomyces cerevisiae, was functionally expressed in Escherichia coli inherently lacking the enzyme. The recombinant E. coli strain expressing the enzyme could overproduce d-erythroascorbic acid and l-ascorbic acid when supplied with d-arabinono-1,4-lactone and l-galactono-1,4-lactone, respectively.

  5. Osteoblastic phenotype of rat marrow stromal cells cultured in the presence of dexamethasone, beta-glycerolphosphate, and L-ascorbic acid

    Science.gov (United States)

    Peter, S. J.; Liang, C. R.; Kim, D. J.; Widmer, M. S.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    We investigated the effects of the time course of addition of osteogenic supplements dexamethasone, beta-glycerolphosphate, and L-ascorbic acid to rat marrow stromal cells, and the exposure time on the proliferation and differentiation of the cells. It was the goal of these experiments to determine the time point for supplement addition to optimize marrow stromal cell proliferation and osteoblastic differentiation. To determine this, two studies were performed; one study was based on the age of the cells from harvest, and the other study was based on the duration of exposure to supplemented medium. Cells were seen to proliferate rapidly at early time points in the presence and absence of osteogenic supplements as determined by 3H-thymidine incorporation into the DNA of replicating cells. These results were supported by cell counts ascertained through total DNA analysis. Alkaline phosphatase (ALP) activity and osteocalcin production at 21 days were highest for both experimental designs when the cells were exposed to supplemented medium immediately upon harvest. The ALP levels at 21 days were six times greater for cells maintained in supplements throughout than for control cells cultured in the absence of supplements for both studies, reaching an absolute value of 75 x 10(-7) micromole/min/cell. Osteocalcin production reached 20 x 10(-6) ng/cell at 21 days in both studies for cells maintained in supplemented medium throughout the study, whereas the control cells produced an insignificant amount of osteocalcin. These results suggest that the addition of osteogenic supplements to marrow-derived cells early in the culture period did not inhibit proliferation and greatly enhanced the osteoblastic phenotype of cells in a rat model.

  6. Abscisic acid enhances tolerance of wheat seedlings to drought and regulates transcript levels of genes encoding ascorbate-glutathione biosynthesis

    Science.gov (United States)

    Wei, Liting; Wang, Lina; Yang, Yang; Wang, Pengfei; Guo, Tiancai; Kang, Guozhang

    2015-01-01

    Glutathione (GSH) and ascorbate (ASA) are associated with the abscisic acid (ABA)-induced abiotic tolerance in higher plant, however, its molecular mechanism remains obscure. In this study, exogenous application (10 ?M) of ABA significantly increased the tolerance of seedlings of common wheat (Triticum aestivum L.) suffering from 5 days of 15% polyethylene glycol (PEG)-stimulated drought stress, as demonstrated by increased shoot lengths and shoot and root dry weights, while showing decreased content of hydrogen peroxide (H2O2) and malondialdehyde (MDA). Under drought stress conditions, ABA markedly increased content of GSH and ASA in both leaves and roots of ABA-treated plants. Temporal and spatial expression patterns of eight genes encoding ASA and GSH synthesis-related enzymes were measured using quantitative real-time reverse transcription polymerase chain reaction (qPCR). The results showed that ABA temporally regulated the transcript levels of genes encoding ASA-GSH cycle enzymes. Moreover, these genes exhibited differential expression patterns between the root and leaf organs of ABA-treated wheat seedlings during drought stress. These results implied that exogenous ABA increased the levels of GSH and ASA in drought-stressed wheat seedlings in time- and organ-specific manners. Moreover, the transcriptional profiles of ASA-GSH synthesis-related enzyme genes in the leaf tissue were compared between ABA- and salicylic acid (SA)-treated wheat seedlings under PEG-stimulated drought stress, suggesting that they increased the content of ASA and GSH by differentially regulating expression levels of ASA-GSH synthesis enzyme genes. Our results increase our understanding of the molecular mechanism of ABA-induced drought tolerance in higher plants.

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

    OpenAIRE

    Ioannidi, Eugenia; Kalamaki, Mary S.; Engineer, Cawas; Pateraki, Irene; Alexandrou, Dimitris; Mellidou, Ifigeneia; Giovannonni, James; Kanellis, Angelos K.

    2009-01-01

    L-Ascorbate (the reduced form of vitamin C) participates in diverse biological processes including pathogen defence mechanisms, and the modulation of plant growth and morphology, and also acts as an enzyme cofactor and redox status indicator. One of its chief biological functions is as an antioxidant. L-Ascorbate intake has been implicated in the prevention/alleviation of varied human ailments and diseases including cancer. To study the regulation of accumulation of this important nutraceutic...

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

    Scientific Electronic Library Online (English)

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

    2014-06-01

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

  9. Estimation of redox potentials of Fe(III)- gallic acid complexes at different pH by spectrophotometric titration with ascorbate

    International Nuclear Information System (INIS)

    Fe(III) is strongly chelated by Gallic acid. This equilibrium as well as the kinetics of reduction of the complex is strongly pH dependent. The complex was prepared in acetate buffers of pH 4.6, 5.0 and 5.6 and in Tris buffer of pH 7.0.The complex was reduced by ascorbate. The reduced absorbance was taken to be a measure of reaction. Nernst equation was then applied to determine the standard redox potentials of the complex taking the literature values of the redox potentials of ascorbate at different pH. The values of redox potentials of complex were found to be 0.197 V at pH 4.6. 0.181 V at pH 5.0 1.132 V at pH 5.6 and 0.092 V at pH 7.0. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-08-01

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

  11. Assay of ascorbic acid in plants tissues, I: 1H and 13C NMR study of the complex between Cu(I) and 2,2'-biquinoline

    International Nuclear Information System (INIS)

    The Shieh's method, originally devised for the analysis of ascorbic acid (AsA) in pharmaceutical preparations and based on the reaction of this acid with Cu(I) and 2,2'-biquinoline, was adapted to determine AsA in biological samples and particularly in plant tissues. The proposed assay is compared with some current methods for AsA determination. Moreover the system Cu(I)-biquinoline is studied by 1H and 13C NMR spectroscopy, and a coordination model for the complex is proposed. (author). 12 refs., 4 figs., 2 tabs

  12. ESR study of photoinduced free radicals by visible light in hair and the effects of ascorbic acid (vitamin C).

    Science.gov (United States)

    Chikvaidze, E; Khachatryan, I

    2011-08-01

    The ESR spectra of melanin's free radicals in natural black and red hair have been investigated. It is shown that the ESR spectrum of black hair is slightly asymmetric singlet with g=2.0037 and ?H=0.5 mTl. The ESR spectrum of red hair with g=2.0053 differs from the spectrum of black hair. Using the method of saturation was shown that ESR spectrum of red hair represents a superposition of two signals: a singlet, relating to the black hair, and a triplet from red hair's pheomelanin. Under the influence of visible light (blue with ?(max) =450 nm, green with ?(max) =510 nm and red with ?(max) =650 nm) in both types of hair (black and red), the photoinduced free radicals appear, which indicates an increase in the intensity of already existing ESR spectrum of hair. It should be noted that the ESR spectra of red hair from various donors are different. The antioxidant ascorbic acid (vitamin C) has the different effect on the photoinduced free radicals. In particular, in the case of black hair, the concentration of photoinduced free radicals is slightly reduced, whereas in red hair, the disappearance of the triplet in the spectrum is observed, and at the same time, the spectrum becomes a singlet, the intensity of which increases sharply. It is assumed that the antioxidants, effective for black hair, may be ineffective for red hair and vice versa. Therefore, in each, specific case is necessary to investigate the effectiveness of an antioxidant separately. PMID:21284658

  13. EPR study of heme x NO complexes of ascorbic acid-reduced Pseudomonas cytochrome oxidase and corresponding model complexes.

    Science.gov (United States)

    Muhoberac, B B; Wharton, D C

    1980-09-25

    The EPR spectra of the NO complexes of frozen solutions of ascorbic acid-reduced cytochrome oxidase (nitrite reductase) purified from Pseudomonas aeruginosa, of its heme d1-depleted form, and of heme d1 in solutions containing various nitrogenous bases are quite similar to each other as well as to several heme (iron protoporphyrin IX)-containing proteins. The NO complexes of heme d1 (an iron-chlorin) in the presence of nitrogenous bases belong to spectral type C according to Kon's classification and, thus, the energy levels of the iron are closely related to thorse of heme complexes recorded under similar conditions. Comparison of these spectra with those of complexes of known structure suggests that both heme c and heme d1 are linked with Pseudomonas cytochrome oxidase by means of a nitrogenous ligand. The EPR spectrum of the NO complex of the native enzyme exhibits a lack of resolution of the high field (gy) resonance which can be characterized in terms of a spectral contribution from both the heme c and heme d1 moieties. The similarity between the EPR spectra of the NO complexes of horse heart cytochrome c and the heme d1-depleted Pseudomonas cytochrome oxidase before and after interaction with urea suggests structural similarities involving the heme irons. The changes caused by urea are likely to be a breaking or distortion of the bond between the iron and the protein-donated nitrogenous ligand and are similar to alterations seen with NO complexes of hemoglobin under a variety of conditions. PMID:6251057

  14. Fabrication of GNPs/CDSH-Fc/nafion modified electrode for the detection of dopamine in the presence of ascorbic acid

    International Nuclear Information System (INIS)

    A novel dopamine sensor was fabricated by forming the inclusion complex between mono-6-thio-?-cyclodextrin (CD-SH) and ferrocene (Fc) functionalized gold nanoparticles (GNPs) films on a platinum electrode. The properties of the GNPs/CDSH-Fc nanocomposite were characterized by Fourier transform infrared spectra, UV-visible absorption spectroscopy, transmission electron microscopy and cyclic voltammetry. The electrochemistry of dopamine (DA) was investigated by cyclic voltammetry (CV) and differential pulse voltammograms (DPV). The electrooxidation of dopamine could be catalyzed by Fc/Fc+ couple as a mediator and had a higher electrochemical response due to the unique performance of GNPs/CDSH-Fc. The anodic peaks of DA and ascorbic acid (AA) in their mixture can be well separated by the prepared electrode. Under optimum conditions linear calibration graphs were obtained over the DA concentration range 2.0 x 10-6 to 5.0 x 10-5 M with a correlation coefficient of 0.998 and a detection limit of 9.0 x 10-8 M (S/N = 3). The modified electrode had been effectively applied for the assay of DA in dopamine hydrochloride injections. This work provides a simple and easy approach to selectively detect DA in the presence of AA. - Research highlights: ? The sensor of DA was constructed by using GNPs/CDSH-Fc as the building block. ? Inclusion complex on the surface of GNPs decreased the leakage of mediator. ? The electro-oxidation of diator. ? The electro-oxidation of DA could be catalyzed by Fc/Fc+ couple as a mediator. ? This work provides a simple approach to selectively detect DA in the presence of AA.

  15. Fabrication of GNPs/CDSH-Fc/nafion modified electrode for the detection of dopamine in the presence of ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ming; Wei Xiujuan; Qian Hui; Diao Guowang, E-mail: gwdiao@yzu.edu.cn

    2011-10-10

    A novel dopamine sensor was fabricated by forming the inclusion complex between mono-6-thio-{beta}-cyclodextrin (CD-SH) and ferrocene (Fc) functionalized gold nanoparticles (GNPs) films on a platinum electrode. The properties of the GNPs/CDSH-Fc nanocomposite were characterized by Fourier transform infrared spectra, UV-visible absorption spectroscopy, transmission electron microscopy and cyclic voltammetry. The electrochemistry of dopamine (DA) was investigated by cyclic voltammetry (CV) and differential pulse voltammograms (DPV). The electrooxidation of dopamine could be catalyzed by Fc/Fc{sup +} couple as a mediator and had a higher electrochemical response due to the unique performance of GNPs/CDSH-Fc. The anodic peaks of DA and ascorbic acid (AA) in their mixture can be well separated by the prepared electrode. Under optimum conditions linear calibration graphs were obtained over the DA concentration range 2.0 x 10{sup -6} to 5.0 x 10{sup -5} M with a correlation coefficient of 0.998 and a detection limit of 9.0 x 10{sup -8} M (S/N = 3). The modified electrode had been effectively applied for the assay of DA in dopamine hydrochloride injections. This work provides a simple and easy approach to selectively detect DA in the presence of AA. - Research highlights: {yields} The sensor of DA