ascorbic-acid and threonic-acid

Ultraviolet irradiation causes adverse effects like sunburn, photosensitivity reactions or immunologic suppression. The aim of this study was to evaluate the photo-protective outcome of a sunscreen cream (SPF8) by the determination of erythema indexes and the assessment of ascorbic acid and its metabolites in human dermis. These substances were used as markers of oxidative effect. Eight healthy female subjects were enrolled in this study. Two abdominal areas were exposed to solar simulated irradiation with three minimal erythema dose, one with SPF8 application and the other site without SPF8 application. Two other areas were used as control, one without SPF8 application and the other site after SPF8 application. Ascorbic acid and its metabolites (dehydroascorbic acid, threonic acid, oxalic acid and xylose) were collected from human dermis by microdialysis and assessed by gas chromatography mass spectrometry. Irradiated site without sunscreen application had significantly demonstrated lower dermis ascorbic acid concentrations and a higher erythema index than the three other sites (P < 0.05). Threonic acid, oxalic acid and xylose dermis concentrations were significantly higher in site III than in the control site I (P < 0.05). The protected-irradiated site did not show erythema formation and there was stability of ascorbic acid dermis concentrations with non-variation in its metabolites. The assessment of ascorbic acid and its metabolites in human dermis could be an efficient tool to demonstrate the oxidative process and consequently to control the efficiency of sunscreen creams against undesirable UV effects.

Topics: Adult; Ascorbic Acid; Benzophenones; Butyrates; Camphor; Chalcones; Dehydroascorbic Acid; Dermis; Drug Combinations; Erythema; Female; Gas Chromatography-Mass Spectrometry; Humans; Microdialysis; Ointments; Osmolar Concentration; Oxalic Acid; Skin; Sunscreening Agents; Ultraviolet Rays; Xylose

Ascorbate content in plants is controlled by its synthesis from carbohydrates, recycling of the oxidized forms and degradation. Of these pathways, ascorbate degradation is the least studied and represents a lack of knowledge that could impair improvement of ascorbate content in fruits and vegetables as degradation is non-reversible and leads to a depletion of the ascorbate pool. The present study revealed the nature of degradation products using [

Topics: Ascorbic Acid; Butyrates; Fruit; Gene Expression Regulation, Plant; Light; NADH, NADPH Oxidoreductases; Oxalates; Oxidation-Reduction; Plant Leaves; Solanum lycopersicum

DFT calculations were carried out to investigate reaction paths of L-ascorbic acid (AAH2), hydroxyl radicals and water clusters. Frontier-orbital analyses were also performed to examine the regioselectivity of the OH˙ addition. Transition states of the electrolytic dissociation of AAH2 and intermediate carboxylic acids were found to have very small activation energies through proton transfers along hydrogen bonds. The ionized species (anions) are subject to the electrophilic attack of OH˙. The elementary processes of AAH2 → A˙(-) → dehydroascorbic acid → diketogulonic acid → threonic, oxalic, xylonic and lyxonic acids were investigated and discussed. The processes involved in the conversion of dehydroascorbic acid into a bicyclic hemiketal were also examined as a side-chain participating reaction. The oxidation and degradation of vitamin C up to threonic acid were described mainly as a donor (AAH2)-acceptor (OH˙) reaction.

Topics: Ascorbic Acid; Butyrates; Carbon Dioxide; Dehydroascorbic Acid; Free Radicals; Hydrogen Bonding; Models, Molecular; Molecular Conformation; Oxalic Acid; Oxidation-Reduction; Quantum Theory; Sugar Acids

To assess in a periodontally diseased rural population deprived from regular dental care and having poor dietary conditions, the effect of vitamin C/calcium threonate/citrus flavonoids (VitC/Ca/Fl) supplementation on subgingival microbiota and plasma levels of vitamin C, HbA1c and hsCRP.. The study population consisted of 98 subjects who previously participated in a prospective study on the natural history of periodontitis. Participants were instructed to consume one tablet/day containing 200 mg Ester C(®) calcium ascorbate, 25 mg calcium threonate and 100 mg citrus flavonoids for 90 days. Following parameters were evaluated: prevalence/amount of seven traditional periodontal pathogens, cytomegalovirus, Epstein-Barr virus (EBV); and plasma levels of vitamin C, HbA1c and hsCRP.. After VitC/Ca/Fl supplementation, 100% of subjects showed normal plasma vitamin C values compared to 55% before. At baseline, 48% of subjects harboured Aggregatibacter actinomycetemcomitans, >97% the other periodontal pathogens and 73% EBV. Supplementation with VitC/Ca/F reduced the subgingival load of all studied bacteria (p-values: 0.014-0.0001) and EBV (p < 0.0001) substantially in all initially positive subjects. Plasma levels of HbA1c and hsCRP dropped in all subjects (p < 0.0001).. This uncontrolled study suggested that supplemental VitC/Ca/Fl may be helpful in reducing subgingival numbers of periodontal pathogens and EBV, and promoting systemic health.

Topics: Aggregatibacter actinomycetemcomitans; Ascorbic Acid; Butyrates; Citrus; Flavonoids; Glycated Hemoglobin; Humans; Indonesia; Periodontal Diseases; Prospective Studies

In a previous study, we recently claimed that dihydrotestosterone (DHT)-inducible dickkopf-1 (DKK-1) expression is one of the key factors involved in androgen-potentiated balding. We also demonstrated that L-ascorbic acid 2-phosphate (Asc 2-P) represses DHT-induced DKK-1 expression in cultured dermal papilla cells (DPCs). Here, we investigated whether or not L-threonate could attenuate DHT-induced DKK-1 expression. We observed via RT-PCR analysis and enzyme-linked immunosorbent assay that DHT-induced DKK-1 expression was attenuated in the presence of L-threonate. We also found that DHT-induced activation of DKK-1 promoter activity was significantly repressed by L-threonate. Moreover, a co-culture system featuring outer root sheath (ORS) keratinocytes and DPCs showed that DHT inhibited the growth of ORS cells, which was then significantly reversed by L-threonate. Collectively, these results indicate that L-threonate inhibited DKK-1 expression in DPCs and therefore is a good treatment for the prevention of androgen-driven balding.

Topics: Alopecia; Androgens; Ascorbic Acid; Butyrates; Cells, Cultured; Chemoprevention; Coculture Techniques; Dermis; Dihydrotestosterone; Down-Regulation; Drug Evaluation, Preclinical; Gene Expression Regulation; Hair Follicle; Humans; Intercellular Signaling Peptides and Proteins; Keratinocytes; Male

Parenteral multivitamin preparation (MVP) induces fatty liver in neonatal guinea pig pups; this is prevented by photoprotection. Photo-excited riboflavin present in MVP generates H(2)O(2) and molecules with masses of 136 and 208. We hypothesized that H(2)O(2) initiates the peroxidation of ascorbic acid (AA), producing biologically active byproducts affecting hepatic lipid metabolism.. Mass spectrometry (MS) documented the participation of H(2)O(2) and photo-excited riboflavin (Ribo) in the formation of AA byproducts. Sixteen 3-day-old guinea pig pups received an intravenous solution (50 g/L dextrose + 4.5 g/L NaCl + 1 kIU/L heparin) at 240 mL x kg(-1) x day(-1), enriched with control or test mixtures, for 4 days. The control mixture was photo-protected AA + Ribo (without byproducts or H(2)O(2)), and the test mixture was AA + Ribo treated to generate AA byproducts without H(2)O(2). Hepatic acetyl-CoA carboxylase (ACC) activity was determined after 4 days. Fourth-day urine samples were analyzed by MS. Data were treated by ANOVA (alpha = 0.05).. H(2)O(2) did not influence the classic degradation of AA, as the generation of 2,3-diketogulonic acid was not affected. In contrast, the formation of molecules with masses of 136 and 208 was H(2)O(2) and time dependent. ACC activity was higher (P <0.01) in animals receiving high concentration of these molecules; its hepatic activation correlated (P <0.01) with the urinary concentration of molecule-208.. H(2)O(2) at concentrations found in the clinical setting of total parenteral nutrition induce the transformation of dehydroascorbic acid into compounds that have the potential to affect lipid metabolism. These molecules have peroxide and aldehyde functions.

Topics: Acetyl-CoA Carboxylase; Animals; Ascorbic Acid; Butyrates; Guinea Pigs; Hydrogen Peroxide; Light; Lipid Metabolism; Liver; Mass Spectrometry; Molecular Structure; Molecular Weight; Oxidation-Reduction; Riboflavin

We have previously shown that vitamin C (ascorbic acid) can initiate hydroxyl radical formation in copper contaminated household drinking water. In the present study, we have examined the stability of vitamin C in copper and bicarbonate containing household drinking water. In drinking water samples, contaminated with copper from the pipes and buffered with bicarbonate, 35% of the added vitamin C was oxidized to dehydroascorbic acid within 15 min. After 3h incubation at room temperature, 93% of the added (2 mM) ascorbic acid had been oxidized. The dehydroascorbic acid formed was further decomposed to oxalic acid and threonic acid by the hydrogen peroxide generated from the copper (I) autooxidation in the presence of oxygen. A very modest oxidation of vitamin C occurred in Milli-Q water and in household water samples not contaminated by copper ions. Moreover, addition of vitamin C to commercially sold domestic bottled water samples did not result in vitamin C oxidation. Our results demonstrate that ascorbic acid is rapidly oxidized to dehydroascorbic acid and further decomposed to oxalic- and threonic acid in copper contaminated household tap water that is buffered with bicarbonate. The impact of consuming ascorbic acid together with copper and bicarbonate containing drinking water on human health is discussed.

Topics: Ascorbic Acid; Butyrates; Chromatography, High Pressure Liquid; Hydrogen Peroxide; Oxalic Acid; Oxidation-Reduction; Water Supply

The degradation of L-ascorbate (AsA) and its primary oxidation products, L-dehydroascorbate (DHA) and 2,3-L-diketogulonate (2, 3-DKG) were studied under physiological conditions. Analysis determined that L-erythrulose (ERU) and oxalate were the primary degradation products of ASA regardless of which compound was used as the starting material. The identification of ERU was determined by proton decoupled (13)C-nuclear magnetic resonance spectroscopy, and was quantified by high performance liquid chromatography, and enzymatic analysis. The molar yield of ERU from 2,3-DKG at pH 7.0 37 degrees C and limiting O(2)97%. This novel ketose product of AsA degradation, was additionally qualitatively identified by gas-liquid chromatography, and by thin layer chromatography. ERU is an extremely reactive ketose, which rapidly glycates and crosslinks proteins, and therefore may mediate the AsA-dependent modification of protein (ascorbylation) seen in vitro, and also proposed to occur in vivo in human lens during diabetic and age-onset cataract formation.

Topics: 2,3-Diketogulonic Acid; Ascorbic Acid; Buffers; Butyrates; Chromatography, High Pressure Liquid; Crystallins; Dehydroascorbic Acid; Humans; Hydrogen-Ion Concentration; Lens, Crystalline; Magnetic Resonance Spectroscopy; Oxalates; Oxidation-Reduction; Temperature; Tetroses

Topics: 2,3-Diketogulonic Acid; Ascorbic Acid; Butyrates; Chemical Precipitation; Dehydroascorbic Acid; Infusions, Intravenous; Oxalic Acid; Oxidation-Reduction; Oxygen; Parenteral Nutrition

Vitamin C or ascorbate is important in wound healing due to its essential role in collagen synthesis. To study wound healing in the periodontium, cells adherent to expanded polytetrafluoroethylene (ePTFE) augmentation membranes, recovered from edentulous ridge augmentation procedures, have been established in culture in our laboratories. The objective of this study was to determine whether treatment of these cells with a calcium ascorbate, which contains vitamin C metabolites (metabolite-supplemented ascorbate), would increase the production of collagenous protein and mineralized tissue in vitro, as compared to unsupplemented calcium ascorbate (ascorbate).. Cells derived from ePTFE membranes were cultured with beta-glycerophosphate and the test agents for 2 to 5 weeks, and the surface areas of the cell cultures occupied by mineralized nodules were measured using computerized image analysis. One experiment tested the effects of calcium threonate, one of the vitamin C metabolites in metabolite-supplemented ascorbate. Incorporation of radioactive proline and glycine was used as a measure of total protein (radioactivity precipitated by trichloracetic acid) and collagenase-digestible protein (radioactivity released by collagenase digestion.) Co-localization of collagen and fibronectin was examined by immunofluorescence.. In vitro treatment of these cells with metabolite-supplemented ascorbate increased the area of the cell cultures occupied by mineralized nodules after 5 weeks. Cell cultures treated with metabolite-supplemented ascorbate also exhibited significant increases in total protein. The increase in collagenous proteins in these cultures accounted for 85% of the increase in total protein. The greatest difference between treatment groups was observed in the cell-associated fraction containing the extracellular matrix. The additional collagen exhibited normal co-distribution with fibronectin. In cultures treated with ascorbate spiked with calcium threonate, the area of mineralized tissue was significantly greater than in ascorbate-treated cultures, but was less than that observed in cultures treated with metabolite-supplemented ascorbate.. In vitro treatment with ascorbate containing vitamin C metabolites enhanced the formation of mineralized nodules and collagenous proteins. Calcium threonate may be one of the metabolites influencing the mineralization process. Identifying factors which facilitate the formation of mineralized tissue has significant clinical ramifications in terms of wound healing and bone regeneration.

Topics: Alveolar Ridge Augmentation; Antioxidants; Ascorbic Acid; Butyrates; Calcium; Cell Line; Cells, Cultured; Collagen; Culture Media; Fibroblasts; Fibronectins; Fluorescent Antibody Technique; Glycerophosphates; Glycine; Humans; Image Processing, Computer-Assisted; Jaw, Edentulous; Membranes, Artificial; Periodontium; Polytetrafluoroethylene; Proline; Protein Biosynthesis; Proteins; Radiopharmaceuticals; Wound Healing

1. Previously, we reported that calcium L-threonate caused a dose-related increase in uptake of ascorbic acid (AA) by human T-lymphoma cells. Preincubation of mouse fibroblasts with calcium L-threonate also resulted in a dose-related augmentation in uptake of AA as compared to non-treated controls. 2. Potassium L-lyxonate increased AA uptake by lymphoma cells, but did not significantly affect uptake by fibroblasts. Tartaric acid decreased uptake of AA by both cell lines. 3. Ouabain and dinitrophenol had no effect on AA uptake nor on the ability of threonate to augment AA uptake by fibroblasts. However, in T-lymphoma cells ouabain and dinitrophenol reduced AA uptake and prevented augmentation of AA uptake by calcium L-threonate.

Topics: 3T3 Cells; Animals; Ascorbic Acid; Butyrates; Humans; Lymphoma, T-Cell; Mice; Sugar Acids; Tumor Cells, Cultured

The effects of preincubation of human T-lymphoma cells with increasing concentrations of calcium L-threonate on the uptake of L-[1-14C]ascorbic acid were examined. Calcium L-threonate (0-1,000 mg%) stimulated ascorbic acid (1.25 mg%) uptake in a dose-dependent manner. These results indicate that calcium threonate and possibly other ascorbic acid metabolites have biological activity and potential pharmacological applications.

Topics: Analysis of Variance; Ascorbic Acid; Butyrates; Dose-Response Relationship, Drug; Humans; Lymphoma, T-Cell; Tumor Cells, Cultured

Threonic acid is a major breakdown product of ascorbic acid used as a food additive. When administered orally to guinea-pigs (100 mg/kg body weight) for periods of 4 or 28 days, it produced a significant fall in the ascorbic acid concentration of certain organs but was without effect on other physiological and biochemical characteristics. The lifespan of scorbutic guinea-pigs was significantly reduced by dietary threonic acid (100 mg/kg body weight). The results indicate that threonic acid may modify the metabolism of ascorbic acid in guinea-pigs.

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Butyrates; Drug Interactions; Food Additives; Guinea Pigs; Hydroxybutyrates; Longevity; Male; Organ Size; Time Factors; Tissue Distribution