Estimation of dehydroascorbic acid in blood of diabetic patients
TL;DR: The DHA from diabetic blood has been isolated as the 2,4-dinitrophenylhydrazone derivative and identified by thin-layer chromatography and spectrophotometry.
About: This article is published in Analytical Biochemistry.The article was published on 1979-10-01. It has received 77 citations till now. The article focuses on the topics: Dehydroascorbic acid & Ascorbic acid.
Citations
More filters
TL;DR: Taking together both the rate constants and the tissue concentrations, the efficacy of ascorbic acid for scavenging superoxide radical in animal tissues appears to be better than that of suPeroxide dismutase.
Abstract: Using acetaldehyde and xanthine oxidase as the source of suPeroxide radical, the second order rate constant for the reaction between ascorbic acid and superoxide radical was estimated to be 8.2 X 107 M-1 s-1. In rats, the average tissue concentration of ascorbic acid was of the order of 10-3 M and that of superoxide dismutase was of the order of 10-6 M. So, taking together both the rate constants and the tissue concentrations, the efficacy of ascorbic acid for scavenging superoxide radical in animal tissues appears to be better than that of suPeroxide dismutase. The significance of ascorbic acid as a scavenger of superoxide radical has been discussed from the point of view of the evolution of ascorbic acid synthesizing capacity of terrestrial vertebrates.
88 citations
Cites methods from "Estimation of dehydroascorbic acid ..."
...Ascorbic acid in different tissues was estimated as 2:4 dinitrophenylhydrazine derivative following the method of Chatterjee and Banerjee (1979)....
[...]
TL;DR: The serum antioxidant carotenoids were inversely associated with HOMA-estimated insulin resistance in non-diabetic subjects, and in male subjects, an inverse association with the serum β-cryptoxanthin concentrations.
77 citations
Cites background from "Estimation of dehydroascorbic acid ..."
...Recent evidence has suggested that antioxidant vitamins and carotenoids may have a protective effect against diabetes mellitus.(6-13)...
[...]
TL;DR: Carnitine production from [1,2,3,4-14C]gamma-butyrobetaine and [methyl-3H]Lys(Me3)-asialofetuin was reduced in perfused livers obtained from ascorbate-deficient guinea pigs.
67 citations
TL;DR: In insight into the mechanism by which ascorbic acid protects against damage by hydroxyl free radicals, it is suggested that the factor is a cytosolic enzyme appropriately referred to as soluble AFR-reductase.
66 citations
TL;DR: T careful handling and processing of samples, combined with appropriate analysis, is crucial for accurate determination of ascorbate and DHA in clinical samples.
Abstract: Vitamin C (ascorbate) is the major water-soluble antioxidant in plasma and its oxidation to dehydroascorbic acid (DHA) has been proposed as a marker of oxidative stress in vivo. However, controversy exists in the literature around the amount of DHA detected in blood samples collected from various patient cohorts. In this study, we report on DHA concentrations in a selection of different clinical cohorts (diabetes, pneumonia, cancer, and critically ill). All clinical samples were collected into EDTA anticoagulant tubes and processed at 4 °C prior to storage at −80 °C for subsequent analysis by HPLC with electrochemical detection. We also investigated the effects of different handling and processing conditions on short-term and long-term ascorbate and DHA stability in vitro and in whole blood and plasma samples. These conditions included metal chelation, anticoagulants (EDTA and heparin), and processing temperatures (ice, 4 °C and room temperature). Analysis of our clinical cohorts indicated very low to negligible DHA concentrations. Samples exhibiting haemolysis contained significantly higher concentrations of DHA. Metal chelation inhibited oxidation of vitamin C in vitro, confirming the involvement of contaminating metal ions. Although EDTA is an effective metal chelator, complexes with transition metal ions are still redox active, thus its use as an anticoagulant can facilitate metal ion-dependent oxidation of vitamin C in whole blood and plasma. Handling and processing blood samples on ice (or at 4 °C) delayed oxidation of vitamin C by a number of hours. A review of the literature regarding DHA concentrations in clinical cohorts highlighted the fact that studies using colourimetric or fluorometric assays reported significantly higher concentrations of DHA compared to those using HPLC with electrochemical detection. In conclusion, careful handling and processing of samples, combined with appropriate analysis, is crucial for accurate determination of ascorbate and DHA in clinical samples.
54 citations
Additional excerpts
...Controls (37) Diabetic–male (25) Diabetic–female (12) 0 12 ± 2 12 ± 2 Heparin MPA DNPH [11]...
[...]
...Abbreviations: SSA, sulfosalicylic acid; TCA, trichloroacetic acid; MPA, metaphosphoric acid; EDTA, ethylenediaminetetraacetic acid; DCPIP, 2,6-dichlorophenol indophenol; DNPH, 2,4-dinitrophenylhydrazine; PDA, 1,2-phenylenediamine; ECD, electrochemical detection....
[...]
References
More filters
Book•
01 Jan 1963
TL;DR: Methods of enzymatic analysis, Methods of enzymes analysis, the authors, Methods of enzyme analysis, enzymatics, methods of enzymes, and methods of analysis, method of enzymes.
Abstract: Methods of enzymatic analysis , Methods of enzymatic analysis , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
18,100 citations
TL;DR: Using the in vitro method, the ascorbic acid synthesizing abilities of different species of animals in the phylogenetic tree are examined, and the results are given below.
Abstract: The requirement of ascorbic acid (vitamin C ) is a common property of living organisms, and it has long been considered that all animals except the guinea pig, monkey, and man can synthesize this vitamin. The classic method for determining the ability of an animal to synthesize ascorbic acid is to feed it a scorbutogenic diet for a prolonged period and to observe the appearance of the scurvy syndrome. Obviously, the method is laborious and time-consuming. Also, the onset of the scorbutic syndrome depends on the ascorbic-acid-retention capacity of the animal. For example, whereas the guinea pigs can be made scorbutic in about 3 weeks, it takes 3 to 4 months to produce scurvy in man. Since the discovery of the technique for studying ascorbic acid synthesir in vitro,1-8 the task has become much simpler. In this technique, the tissue homogenates or the subcellular fractions are incubated with precursors of ascorbic acid and the amount of the vitamin formed is estimated. Using the in vitro method, we have examined the ascorbic acid synthesizing abilities of different species of animals in the phylogenetic tree, and the results are given below.
331 citations
TL;DR: Methods for determinations of vitamin C dehydro-Z-ascorbic (DHA), DHA, and DKA in the presence of each other are reported, indicating that these derivatives are identical substances.
268 citations
TL;DR: An account is given of a new method, based on the two findings that homocysteine rapidly reduces dehydroascorbic acid at pH 7 0, and that under certain simple conditions 2:6-dichlorophenolindophenol can be used to estimate ascorbic acid in the presence of homocy steine without interference from the latter compound.
Abstract: Two main methods are in current use for the estimation of dehydroascorbic acid. In the one, developed by Roe and his colleagues (Roe & Kuether, 1943; Roe, Mills, Oesterling & Damron, 1948), the dehydroascorbic acid is condensed with 2:4-dinitrophenylhydrazine and the product treated with sulphuric acid to give a red colour, the intensity of which is measured photoelectrically. In a second technique (Tillmans, Hirsch & Siebert, 1932; Eekelen, Emmerie, Josephy & Wolff, 1933; Bessey, 1938), dehydroascorbic acid is measured as acorbic acid after reduction with hydrogen sulphide and removal of excess of reductant. Disadvantages are associated with both methods; they are nonspecific for dehydroascorbic acid, timeand labourconsuming, and in the method involving reduction with hydrogen sulphide it may be difficult to ensure the removal ofexcess ofreductant before estimating the ascorbic acid formed with 2:6-dichlorophenolindophenol. In this paper an account is given ofanew method, based on the two findings that homocysteine rapidly reduces dehydroascorbic acid at pH 7 0, and that under certain simple conditions 2:6-dichlorophenolindophenol can be used to estimate ascorbic acid in the presence of homocysteine without interference from the latter compound.
124 citations