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At least 19 recordsLinked to original sources
PubMed2004

Localization of ascorbic acid, ascorbic acid oxidase, and glutathione in roots of Cucurbita maxima L.

To understand the function of ascorbic acid (ASC) in root development, the distribution of ASC, ASC oxidase, and glutathione (GSH) were investigated in cells and tissues of the root apex of Cucubita maxima. ASC was regularly distributed in the cytosol of almost all root cells, with the exception of quiescent centre (QC) cells. ASC also occurred at the surface of the nuclear membrane and correspondingly in the nucleoli. No ASC could be observed in vacuoles. ASC oxidase was detected by immunolocalization mainly in cell walls and vacuoles. This enzyme was particularly abundant in the QC and in differentiating vascular tissues and was absent in lateral root primordia. Administration of the ASC precursor L-galactono-gamma-lactone markedly increased ASC content in all root cells, including the QC. Root treatment with the ASC oxidized product, dehydroascorbic acid (DHA), also increased ASC content, but caused ASC accumulation only in peripheral tissues, where DHA was apparently reduced at the expense of GSH. The different pattern of distribution of ASC in different tissues and cell compartments reflects its possible role in cell metabolism and root morphogenesis.

Amaryllidaceae Alkaloids↗
PubMed1984

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

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

Allantoin↗
PubMed2000

Inhibition of Aeromonas caviae and A. sobria by sodium choloride, citric acid, ascorbic acid, potassium sorbate and extracts of Thymus vulgaris.

The respective and combined effects of sodium chloride, ascorbic acid, citric acid, potassium sorbate, and Thymus vulgaris extract on the growth of Aeromonas caviae and Aeromonas sobria were investigated. Sodium chloride (3%) significantly reduced the growth and 4% NaCl inhibited growth of the tested strains. Ascorbic acid (0. 1%), potassium sorbate (0.05%), and citric acid (0.03%) slightly inhibited growth. T. vulgaris extract (0.3%) greatly reduced the growth. Various combinations of these compounds prevented growth of the tested strains. A combination of NaCl (3%) and ascorbic acid (0. 1%), citric acid (0.03%) and potassium sorbate (0.05%), or citric acid (0.03%) and ascorbic acid (0.1%) inhibited growth of A. caviae and A. sobria. In fish homogenates, the addition of ascorbic acid (0. 1%) and citric acid (0.03%) was the most effective combination tested.

Aeromonas↗
PubMed2000

Antioxidant activity and xanthine oxidase inhibition activity of reductic acid: ascorbic acid analogue.

Reductic acid (2,3-dihydroxy-2-cyclopentenone, 1) decreased the ESR signal of 5,5-dimethyl-1-pyrroline 1-oxide (DMPO)-OH produced by hydroxyl radical and DMPO. 1 also inhibited lipid peroxidation initiated by cytochrome P450 and tert-butyl hydroperoxide. 1 inhibited xanthine oxidase activity, while ascorbic acid and 2-hydroxytetronic acid, an ascorbic acid analogue without side chain, did not.

Animals↗
PubMed2002

Effects of alpha lipoic acid, ascorbic acid-6-palmitate, and fish oil on the glutathione, malonaldehyde, and fatty acids levels in erythrocytes of streptozotocin induced diabetic male rats.

In this research, it has been aimed to evaluate the improvement effects of alpha lipoic acid (ALA), ascorbic acid-6-palmitate (AA6P), fish oil (FO), and their combination (COM) on some biochemical properties in erythrocytes of streptozotocin (STZ)-induced diabetic male rats. According to experimental results, glutathione (GSH) level in erythrocytes decreased in diabetes (P < 0.01), D + ALA, and D + AA6P groups (P < 0.001). Malonaldehyde (MA) level increased in diabetes (P < 0.05), D + FO, and D + COM groups (P < 0.001), but its level in D + AA6P and D + ALA groups was lower in diabetes group (P < 0.01). Total lipid level in diabetes and diabetes plus antioxidant administered groups were higher than control. Total cholesterol level was high in diabetes and D + ALA groups (P < 0.05), but its level reduced in D + FO compared to control and diabetes groups, P < 0.05, < 0.001, respectively. Total triglyceride (TTG) level was high in the D + ALA (P < 0.05) and D + COM (P < 0.001) groups. In contrast, TTG level in blood of diabetes group was higher than diabetes plus antioxidant and FO administered groups (P < 0.001). According to gas chromatography analysis results, while the palmitic acid raised in diabetes group (P < 0.05), stearic acid in D + FO, D + ALA, and diabetes groups was lower than control (P < 0.05), oleic acid reduced in D + COM and D + FO groups, but its level raised in D + AA6P and D + ALA groups (P < 0.01). As the linoleic acid (LA) elevated in ALA + D, D + AA6P, and diabetes groups, linolenic acid level in diabetes, D + AA6P, and D + FO groups was lower than control (P < 0.001). Arachidonic acid (AA) decreased in D + ALA, D+ AA6P, and diabetes groups (P < 0.01), but its level in D + COM and D + FO was higher than control (P < 0.05). Docosahexaenoic acid (DHA) increased in D + AA6P and D + COM (P < 0.05). While the total saturated fatty acid level raised in diabetes group, its level reduced in D + ALA and D + FO groups (P < 0.05). In contrast, total unsaturated fatty acid level in D + ALA and D + FO groups was higher than control (P < 0.05). In conclusion, present data have confirmed that the combination of the ALA, AA6P, and FO have improvement effects on the recycling of GSSG to reduced GSH in erythrocytes of diabetic rats, and in addition to this, oxidative stress was suppressed by ALA and AA6P, and unsaturated fatty acid degree was raised by the effects of ALA and FO.

Animals↗
PubMed2006

Kinetics of ozone reaction with uric acid, ascorbic acid, and glutathione at physiologically relevant conditions.

This study quantified the reaction kinetics of O3 with three low molecular weight antioxidants-uric acid (UA), ascorbic acid (AH2), and glutathione (GSH)-found in respiratory mucous. Using a semi-batch reactor in which a 500 ml/min flow of air containing 1-5 parts per million of O3 contacted 3 ml of well-stirred physiological saline solution containing 100-200 microM antioxidant, we found that: (1) mass transfer resistances in the gas and liquid phases were successfully eliminated by the reactor design; (2) the reaction of O3 with UA, AH2 and GSH had stoichiometries of 1:1, 1:1, and 1:2.5, respectively; (3) the reactivity between O3 and antioxidants was in the order UA approximately AH2>GSH. Simulating the measured amounts of O3 absorbed and antioxidant consumed with a mathematical model, reaction rate constants of O(3) with UA, AH2, and GSH were found to be 5.83 x 10(4) M(-1) s(-1), 5.5 x 10(4) M(-1) s(-1), and 57.5 M(-0.75) s(-1), respectively.

Antioxidants↗
PubMed2000

Microfabricated electrophoresis chips for simultaneous bioassays of glucose, uric acid, ascorbic acid, and acetaminophen.

A micromachined capillary electrophoresis chip is described for simultaneous measurements of glucose, ascorbic acid, acetaminophen, and uric acid. Fluid control is used to mix the sample and enzyme glucose oxidase (GOx). The enzymatic reaction, a catalyzed aerobic oxidation of glucose to gluconic acid and hydrogen peroxide, occurs along the separation channel. The enzymatically liberated neutral peroxide species is separated electrophoretically from the anionic uric and ascorbic acids in the separation/reaction channel. The three oxidizable species are detected at the downstream gold-coated thick-film amperometric detector at different migration times. Glucose can be detected within less than 100 s, and detection of all electroactive constituents is carried out within 4 min. Measurements of glucose in the presence of acetaminophen, a neutral compound, are accomplished by comparing the responses in the presence and absence of GOx in the running buffer. The reproducibility of the on-chip glucose measurements is improved greatly by using uric acid as an internal standard. Factors influencing the performance, including the GOx concentration, field strength, and detection potential, are optimized. Such coupling of enzymatic assays with electrophoretic separations on a microchip platform holds great promise for rapid testing of metabolites (such as glucose or lactate), as well as for the introduction of high-speed clinical microanalyzers based on multichannel chips.

Acetaminophen↗
PubMed1989

Separation of three commercial forms of vitamin C (ascorbic acid, ascorbic-2-sulfate and ascorbate-2-polyphosphate) by HPLC.

A modification of an existing separation technique by this laboratory is described for the separation and quantification of the three commercially available forms of ascorbic acid. The technique has the potential for identifying the various metabolic and degradation products resulting from vitamins C2 and C3 metabolism. A microwave technique is used for tissue heat denaturation and extraction.

Animals↗
PubMed2002

Folic acid, ascorbic acid and sodium selenite restore the motility of Dictyostelium discoideum inhibited by triethyllead.

The effect of triethyllead (TriEL) on motile activity, structure of cytoskeleton and chemotaxis of Dictyostelium discoideum amoebae in developing concentration gradients of folic acid (FA) and cAMP has been studied. It was observed that 3 microM TriEL had little or no effect on locomotion and chemotactic response of cells, whereas 5 microM TriEL strongly reduced the motile activity of Dictyostelium discoideum amoebae and inhibited their chemotaxis towards cAMP, but not towards FA. FA was found to restore the motile activity of Dictyostelium discoideum, inhibited by TriEL. A similar effect was observed in the presence of other antioxidants, i.e. ascorbic acid and sodium selenite, suggesting that oxidative stress may be involved in the action of TriEL. Moreover, the treatment of Dictyostelium amoebae with 5 microM TriEL caused disruption of microtubules while 3 microM TriEL had little effect on their structure. FA caused restoration of microtubules only in some cells within 1 h of incubation, i.e. when the directional movement of cells towards this chemoattractant was already observed. However, their organization was significantly different from that observed in the untreated cells, suggesting that microtubule undisturbed organisation may be not necessary for Dictyostelium discoideum amoebae locomotion and chemotaxis

Actins↗
PubMed1996

Gluconeogenesis from ascorbic acid: ascorbate recycling in isolated murine hepatocytes.

Ascorbic acid synthesis and breakdown were investigated in isolated hepatocytes prepared from fasted mice. Stimulation of gluconeogenesis by alanine or xylitol led to ascorbate synthesis. On the other hand, ascorbate or dehydroascorbate addition resulted in concentration-dependent glucose production and elevation of the pentose phosphate pathway intermediate xylulose 5-phosphate. Stimulation of ascorbate oxidation and/or the inhibition of dehydroascorbate reduction increased glucose formation. Inhibition of the pentose phosphate pathway decreased glucose production from dehydroascorbate with increased accumulation of xylulose 5-phosphate. These results suggest that ascorbate can be recycled by a novel way involving intermediates of the pentose phosphate pathway, gluconeogenesis and hexuronic acid pathway.

Animals↗