A Facile Preparation of Dehydro-<scp>l</scp>-ascorbic Acid-methanol Solution and Its Stability

“…Since the commer cial grades of DERA and DASA were not pure enough for our experiments (18,19), DERA and DASA were prepared by the method of Ohmori and Takagi (20). Briefly, activated charcoal (Norit "SX Plus" obtained from Wako Pure Chemical Industries, Ltd.) was added to ERA or ASA dissolved in methanol.…”

Section: Methodsmentioning

confidence: 99%

Reduction of Dehydroerythorbic Acid in Vitamin C-Deficient Guinea Pigs.

Yan

Otsuka

Fujiwara

2001

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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SummaryA reduction of dehydroerythorbic acid (DERA) to erythorbic acid (ERA) in vitamin C-deficient guinea pigs was evaluated and compared with that of dehydroascorbic acid (DASA). Thirty-six guinea pigs were fed with vitamin C-deficient diets for 18 days. On day 19, the guinea pigs were divided into four groups for the administration of 100mg of DERA, ERA, ascorbic acid (ASA), or DASA every day. After 12 days of oral administration, the concentration of DERA, ERA, ASA, and DASA in the liver, adrenal, spleen, kidney, and plasma of guinea pigs was determined by HPLC. A recovery from scurvy was measured in terms of weight gain and serum alkaline phosphatase activity. All four groups showed simi lar recovery, indicating that the oral administration of relatively high concentrations of DERA reversed the effects of scurvy in vitamin C-deficient guinea pigs. In spite of DERA or DASA administration, ERA or ASA was mainly detected in the tissues. The reduction ratios of DEAR and DASA were similar (approximately 80%) in all tissues except spleen. These re sults suggest that both DASA and DERA are taken up and reduced to ASA or ERA in viva. Key Words ASA, DASA, ERA, DERA, vitamin C-deficiency ERA, also known as D-isoascorbic acid or D araboascorbic acid, is the stereoisomer of ASA, differing the spatial configuration of the hydroxyl group at car bon 5. The endiol group of the lactone ring of ERA and ASA exhibits the same acidic and reducing properties. ERA is widely used as an antioxidant for food additive. The antiscorbutic activity of ERA has been reported to be much lower than that of ASA (1-3). The vitamin C activity of ERA is reported as 1/20 or less of ASA be cause of the poor tissue uptake of ERA (4).On the other hand, DASA, an oxidized form of ASA, is known to display vitamin C activities following the re duction to ASA in animal tissues (5-7). DASA is trans ported via GLUT (8, 9), whereas ASA is transported via sodium-dependent ascorbic acid transporters (10). Following uptake, DASA is reduced to ASA either by the enzyme action (11-15) or by the direct chemical reac tion with GSH (16). The antiscorbutic effect of DASA in vitamin C-deficient guinea pigs is reported to be less than that of ASA (5, 17).The mechanism by which DERA is metabolized in vivo is not known. However, based on the similarities in chemical structure, it is proposed that DERA is taken up and reduced to ERA in a manner similar to DASA. The purpose of this study is to investigate the reduction of DERA to ERA in guinea pigs and to compare the vita min C activity of DERA and DASA with that of ASA in scorbutic guinea pigs. Materials and MethodsMaterials, ERA and ASA were obtained from Wako Pure Chemical Industries, Ltd. (Osaka, Japan). All the reagents were analytical grade.Preparation of DERAA and DASA. Since the commer cial grades of DERA and DASA were not pure enough for our experiments (18, 19), DERA and DASA were prepared by the method of Ohmori and Takagi (20). Briefly, activated charcoal (Norit "SX Plus" obtained from Wako Pure Chemical Indus...

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“…Preparation of DHA and its derivatives Preparation of DHA was carried out by the method described in the literature (Ohmori & Takagi, 1978), and DHA was obtained as a pale syrup which was kept in a freezer at -20'C before use. Acetylation of DHA was made as follows: DHA syrup ( I .O g) was completely dried in a vacuum desiccator, and the dried DHA was dissolved in 6 ml pyridine and added to 6 ml acetic anhydride while stirring and cooling in an ice water bath.…”

Section: Methodsmentioning

confidence: 99%

“…For example, most of the DHA preparations used in these studies on the elucidation of the biological function of DHA were obtained by the oxidation of ASA with oxygen gas in the presence of active carbon in methanol (MeOH) or ethanol (EtOH) (Ohmori & Takagi, 1978), and these preparations have been known to contain MeOH or EtOH complex whose structure has never been clarified. In this study, in order to clarify these points to some extent, some spectroscopic measurements and also semi-empirical molecular orbital (MO) calculations were made to obtain more detailed infoamation about the structure and chemical characteristics of DHA in solutions.…”

mentioning

confidence: 99%

Structure and Chemical Characteristics of Dehydro-L-Ascorbic Acid in Solutions.

Nishikawa

Kurata

1998

FSTI

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L-Ascorbic acid (ASA) plays an important role in food and biological systems as an electron donor, and in the electron-donating process, ASA itself is generally oxidized to dehydro-L-ascorbic acid (DHA). The structure of DHA was reconfirmed to be monohydrated bicyclic structure in an aqueous solution. It was also clarified that DHA had the solvated bicyclic structure in methanol and ethanol solutions, and in these cases, the enantiomers were formed by the solvation of the C2 carbonyl group. When these solvated bicyclic DHA were dissolved in water, the solvent molecule on the solvated C2 carbonyl group was very easily replaced with a water molecule. From the results of MOPAC calculations, the heat of formation of C2 hydrated bicyclic DHA was estimated to be -299.2 kcal/mol, and DHA was clarified to be considerably stabilized by hydration. Furthermore, it was indicated that bicyclic DHA had more compact and less polar structure than ASA.

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A Facile Preparation of Dehydro-l-ascorbic Acid-methanol Solution and Its Stability

Cited by 13 publications

References 1 publication

Effect of l‐Ascorbic Acid on the Rheological Properties of Wheat Flour‐Water Dough

Effect of l‐Ascorbic Acid on the Rheological Properties of Wheat Flour‐Water Dough

Reduction of Dehydroerythorbic Acid in Vitamin C-Deficient Guinea Pigs.

Structure and Chemical Characteristics of Dehydro-L-Ascorbic Acid in Solutions.

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