Book ChapterDOI
Selected methods for the determination of ascorbic acid in animal cells, tissues, and fluids
TLDR
This chapter discusses selected methods for the determination of ascorbic acid in animal cells, tissues, and fluids and suggests that prompt stabilization is especially important in the case of plasma or serum.Abstract:
Publisher Summary This chapter discusses selected methods for the determination of ascorbic acid in animal cells, tissues, and fluids. Methods for determining ascorbic acid are numerous. In general, chemical analyses for the vitamin are divided into two groups; the determination of the reduced form and the determination of the oxidized form. The former group of analyses is usually based upon the oxidation–reduction properties of ascorbic acid. These are widely used as the fundamental reactions in the measurement of vitamin C. The latter group of analyses is usually based upon the oxidation of the ascorbic acid and the subsequent formation of a hydrazone or a fluorophore. Best results are obtained if samples, especially plasma, are quickly stabilized with either trichloroacetic acid or metaphosphoric acid and immediately analyzed. Prompt stabilization is especially important in the case of plasma or serum. The greater stability of ascorbic acid in acid solution is because of the decreased tendency for the hydrolysis of the lactone ring with decreasing pH.read more
Citations
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Journal ArticleDOI
Apoplastic Synthesis of Nitric Oxide by Plant Tissues
TL;DR: The data presented in this report strongly support the hypothesis that plant tissues also synthesize NO via the nonenzymatic reduction of apoplastic nitrite and may have possible significance for germinating grain and for plant roots.
Journal ArticleDOI
The redox couple between glutathione and ascorbic acid: a chemical and physiological perspective.
TL;DR: The evidence for and the evidence against the presence of the enzyme dehydroascorbate reductase in animal cells is outlined in a balanced way in an attempt to make sense of this continuing controversy.
Journal ArticleDOI
Antihyperglycaemic and antioxidant effect of rutin, a polyphenolic flavonoid, in streptozotocin-induced diabetic wistar rats.
TL;DR: Results show that rutin exhibits antihyperglycaemic and antioxidant activity in streptozotocin-induced diabetic rats.
Journal ArticleDOI
A fluorescence-based method for measuring total plasma antioxidant capability
TL;DR: Either other compounds present in plasma are likely to exert antioxidant action, or a marked synergistic action between antioxidants should be postulated to exist, as the latter hypothesis is supported by the finding that the simultaneous inactivation of ascorbate and thiol groups produces a loss in antioxidant capacity of plasma greater than the sum of the decreases produced by the separate in activation of each of the two compounds.
Journal ArticleDOI
Relationship between CO2 Assimilation, Photosynthetic Electron Transport, and Active O2 Metabolism in Leaves of Maize in the Field during Periods of Low Temperature
TL;DR: Measurements of the quantum efficiencies of photosynthetic electron transport through photosystem II (phiPSII) and CO2 assimilation (phiCO2) were made simultaneously on leaves of maize crops in the United Kingdom during the early growing season, when chilling conditions were experienced, supporting the hypothesis that the relative flux of photosynthesis reducing equivalents to O2 via the Mehler reaction is higher when leaves develop under chilling conditions.
References
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Journal ArticleDOI
Methods for detecting and evaluating ascorbic acid deficiency in man and animals
TL;DR: Experimental results that define possible means for measuring tissue levels as an indication of the nutritional status for ascorbic acid follow, which suggest that the transition from optimal to suboptimal nutrition is gradual with few signposts.
Journal ArticleDOI
The use of p-chloromercuribenzoic acid in the determination of ascorbic acid with 2:6-dichlorophenolindophenol
J. A. Owen,Betty Iggo +1 more
TL;DR: In an attempt to devise a specific yet simple method for the determination of ascorbic acid in mammalian tissues, p-chloromercuribenzoic acid successfully suppresses the interference due to thiol compounds.
Journal Article
An improved method for the measurement of leucocyte ascorbic acid concentrations.
H. S. Loh,C. W. M. Wilson +1 more
TL;DR: An improved method for measuring leucocyte ascorbic acid concentrations which employs sodium metrizoate instead of dextraven for separation of red blood cells out of the supernatant fluid is described.
Journal ArticleDOI
Interference by ascorbate-2-sulfate in the dinitrophenylhydrazine assay of ascorbic acid.
Journal ArticleDOI
Effects of dietary ascorbic acid supplementation on hepatic drug-metabolizing enzymes in the guinea pig
TL;DR: In the post-microsomal supernatant, overall glutathione S-aryl transferase activity was significantly lower in the group with the lowest supplementation of ascorbic acid, as compared to the three higher groups.