D-isoascorbic Acid Research Articles

Vitamin C activity of D-isoascorbic acid for the guinea pig

Guinea pigs fed with a synthetic diet or a rabbit ration were depleted of vitamin C for 17 days. The scorbutic animals were treated daily during 2 months with 40 mg D-isoascorbic acid (IAA) or 2 mg L-ascorbic acid (AA). Both isomers restored the growth of the animals and caused the disappearance of scorbutic symptoms. For 3 weeks, the two diets gave similar response, after which the animals fed with the rabbit ration grew much less. Animals given IAA ate less and had smaller weight gains than those given AA; this effect was overcome by pair-feeding. Only a small proportion of administered IAA was recovered in the organs and in the urine. The total ascorbic acid content (AA and IAA) of the IAA-treated animals was less than that of the AA-treated animals. The low AA content of the organs of the IAA-treated animals indicated that IAA had no significant sparing action on AA.

Turnover rates of D-isoascorbic acid and L-ascorbic acid in guinea pig organs.

To elucidate the mode of action of D-isoascorbic acid (IAA) in exerting vitamin C activity for guinea pigs, it was necessary to determine the turnover rate of this ascorbic acid in their organs as well as its effect on the turnover of L-ascorbic acid (AA). Guinea pigs were saturated with either IAA or AA, and the organ contents of the isomers were determined at different intervals of depletion. In a second experiment, guinea pigs previously saturated with AA were injected intraperitoneally with L-ascorbic-1-14C acid. Twenty-four hours after injection, L-ascorbic-1-14C acid was measured in the organs of some of the animals; three groups were formed with the other animals: group 1 was fed with a diet deficient in vitamin C, group 2 with the diet plus 0.1% AA, and group 3 with the diet plus 2% IAA. The L-ascorbic-1-14C acid content of the organs was determined on different days. It was found that the rate of IAA turnover was much more rapid than that of AA in all organs. Furthermore, IAA increased rather than decreased the turnover of AA.

The uptake of D-araboascorbic acid (D-isoascorbic acid) by guinea-pig tissues.

1. Guinea-pigs on a low, controlled intake of ascorbic acid (0.3 mg/100 g body-weight) were given daily an oral supplement of L-ascorbic acid (AA) or of D-isoascorbic acid (isoAA) (both 1.5 mg/100 g body-weight). The AA was deposited in the tissues, the isoAA was not.2. Intramuscularly administered isoAA was deposited in the tissues but not to the same extent as equivalent amounts of intramuscularly administered AA.3. Paper chromatography confirmed that intramuscularly administered isoAA was deposited in the tissues as isoAA, i.e. there was no conversion into AA.4. It is concluded that in guinea-pigs (a)AA is absorbed from the gastro-intestinal tract much more readily than isoAA and (b)AA is either more readily abstracted from the blood or is more readily retained by the tissues or both, than is isoAA.

Differential determination of D-isoascorbic acid and L-ascorbic acid in guinea pig organs.

To test the theory that D-isoascorbic acid (IAA) was not retained by the organs of animals, guinea pigs were fed a synthetic diet containing ascorbic acid (AA) plus IAA. The incorporation of IAA and AA was determined by making use of the different rates of osazone formation of oxidized AA and IAA with 2,4-dinitrophenylhydrazine. It was found that the organs of the guinea pigs retained a significant quantity of IAA which replaced a corresponding quantity of AA. The incorporated IAA could, in turn, be replaced by AA when only AA was subsequently given in the diet.

Human dermal fibroblasts in monolayer tissue culture. Effect of ascorbic acid analogues.

Abstract The effect of some ascorbic acid analogues and two other reducing substances on collagen synthesis, as well as on cell growth and acid mucopolysaccharide production, was studied in monolayer tissue culture of human dermal fibroblasts. d-isoascorbic acid was as effective as l-ascorbic acid in promoting collagen synthesis if the comparison was made at relatively high concentrations such as 200 μg per milliliter of culture medium. Dehydroascorbic acid was ineffective when it was added alone, but was effective when added with cysteine, although inferior to equivalent amounts of ascorbic acid. Neither cysteine nor hydroquinone affected hydroxyproline synthesis. Cysteine seemed to have a sparing effect when it was added with ascorbic acid. It is suggested that the active site of ascorbic acid in hydroxyproline synthesis is its hydroxyradical or radicals and that there is a relative lack of stereospecificity for this vitamin.

Zum wirkungsmechanismus der ascorbinsäure I. Isolierung einer ascorbinsäureabhängigen DPNH-oxydase aus nebennierenmikrosomen

1. 1. An enzyme system has been isolated from suprarenal microsomes that oxidizes DPNH in the presence of ascorbic acid and O 2. 2. 2. The spectra and absorption maxima point to a flavin constituent and cytochrome b 5 as components. 3. 3. The enzyme system contains SH groups, which are concerned in the enzyme reaction described. The reaction is entirely blocked by p-chloromercuri-benzoate. The enzyme is also blocked by Mn ++, but not by KCN, NaN 3, monoiodoacetic acid, or antimycin A. 4. 4. Neither dehydroascorbic acid, nor glutathione, nor adrenalin, can displace ascorbic acid. D-Isoascorbic acid is active but distinctly weaker than ascorbic acid itself. Under the experimental conditions described, TPNH is not oxidized in the presence of ascorbic acid. 5. 5. Fe +++ in complex form is reduced by DPNH in the presence of the enzyme. 6. 6. The speed of the DPNH-oxidation by ascorbic acid is dependent on the O 2 content of the reaction medium. 7. 7. On the basis of the experiments it appears that “monodehydroascorbic acid” acts as an intermediary electron acceptor. The system ascorbic acid ⤥ monodehydroascorbic acid forms the electron carrier between DPNH and O 2. Intermediary hydroxyl radicals probably arise in this way.

The atypical ascorbic acid oxidase in fungus spores—Its inactivation by isoascorbate and its specificity

The enzyme of Myrothecium verrucaria spores has an indicated absolute specificity for l-ascorbic acid and is irreversibly inactivated by d-isoascorbic acid, oxygen being necessary for this reaction. It is postulated that a stable ternary complex is formed between enzyme, isoascorbate, and oxygen. Studies of the inactivation show it to be markedly affected by pH and to have a positive temperature coefficient. Results of further studies on certain characteristics of the enzyme are reported.

THE REACTION OF L-ASCORBIC AND D-ISOASCORBIC ACID WITH NICOTINIC ACID AND ITS AMIDE

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTHE REACTION OF L-ASCORBIC AND D-ISOASCORBIC ACID WITH NICOTINIC ACID AND ITS AMIDEWILHELM WENNERCite this: J. Org. Chem. 1949, 14, 1, 22–26Publication Date (Print):January 1, 1949Publication History Published online1 May 2002Published inissue 1 January 1949https://doi.org/10.1021/jo01153a004RIGHTS & PERMISSIONSArticle Views255Altmetric-Citations14LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (325 KB) Get e-Alerts Get e-Alerts

Effect of Ascorbic Acid on Diabetogenic Action of Alloxan

SummaryAdministration of ascorbic acid to rats which are given low doses of alloxan increases the diabetogenic action of the alloxan. To obtain this effect the alloxan must be given within a minute after the administration of the ascorbic acid. d-Isoascorbic acid? on the other hand, does not produce the potentiation of the alloxan diabetes.

D-Isoascorbic Acid as an Antioxidant.

d-Isoascorbic Acid as an Antioxidant.

Studies on the Stabilization of Carotene in Dehydrated Feeds and Foods

Summary 1. The effects of various physical and chemical treatments upon the stability of carotene in dehydrated alfalfa and oats were studied. 2. Additional heat treatment was effective in decreasing the loss of carotene in dehydrated oats from 70–80 per cent to 30–50 per cent in six months. The loss in one sample of dehydrated alfalfa was reduced from 70 to 50 per cent in six months. 3. The addition of 0.9 per cent diphenylamine to dehydrated oats reduced the loss of carotene from 77 to 41 per cent in six months. The loss of carotene from dehydrated alfalfa was reduced from 60 to 30 per cent in three months by the addition of diphenylamine. 4. In the concentrations and conditions used, the following were ineffective in reducing the loss of carotene during storage: sodium thiosulfate, sulfuric acid, glucoascorbic acid, d-isoascorbic acid, sodium isoascorbate, guaiac, citric acid, tartaric acid, phosphoric acid, sodium bicarbonate, disodium phosphate, urea, ammonia, alpha-tocopherol and hydroquinone. 5. Protection of dehydrated oats from the air by pelleting and coating with Plexowax reduced the loss of carotene from 74 to 45 per cent in six months. 6. Dehydrated sweet potatoes, stored as slices, lost only 5 per cent of their carotene in six months. When ground and stored, the loss of carotene was 65 per cent in six months. 7. Dehydrated diced carrots lost no carotene during the first three months of storage, and lost 25 per cent during the second three months; when the dehydrated diced carrots were compressed into pellets, breaking the outer surface, the loss was 66 per cent in six months. The loss of carotene from dehydrated sliced carrots was much more rapid than from dehydrated diced carrots.

Fatty acid monoesters of 1-ascorbic acid and d-isoascorbic acid

Fat-soluble fatty acid monoesters of 1-ascorbic acid (vitamin C) and d-isoascorbic acid have been prepared from lauric, myristic, palmitic, and stearic acids in 40–50 per cent yields. Evidence has been presented to show that only the primary hydroxyl group of each of the ascorbic acids has been esterified. Antioxidant properties of these esters are being studied. Preliminary tests on the esters have indicated that they may have useful properties as interfacial modifiers.