Showing papers on "Dehydroascorbic acid published in 2010"
TL;DR: The mechanisms allowing the cellular transport of ascorbic acid represent a primary aspect for the understanding of the roles played by this vitamin in pathophysiology as mentioned in this paper, and a large amount of research effort has been spent in the field, on several animal models and different cell types.
183 citations
TL;DR: In this paper, a chimeric construct consisting of the double CaMV35S promoter fused to the Myc-dhar gene was introduced into Arabidopsis thaliana.
Abstract: Vitamin C (L-ascorbic acid, AsA) has important antioxidant and metabolic functions in both plants and animals. Once used, ascorbic acid can be regenerated from its oxidized form in a reaction catalyzed by dehydroascorbate reductase (DHAR, EC 1.8.5.1). To analyze the physiological role of DHAR catalyzing the reduction of DHA to ascorbate in environmental stress adaptation, we examined whether increasing the level of AsA through enhanced AsA recycling would limit the deleterious effects of oxidative stress. A chimeric construct consisting of the double CaMV35S promoter fused to the Myc-dhar gene was introduced into Arabidopsis thaliana. Transgenic plants were biochemically characterized and tested for responses to oxidative stress. Western blot indicated that the dhar-transgene was successfully expressed. In homozygous T4 transgenic seedlings, DHAR overexpression was increased up to 1.5 to 5.4 fold, which enhanced foliar ascorbic acid levels 2- to 4.25-fold and ratio of AsA/DHA about 3- to 16-fold relative to wild type. In addition, the level of glutathione, the reductant used by DHAR, also increased as did its redox state. When whole plants were treated with high light and high temperature stress or in vitro leaf discs were subjected to 10 μM paraquat, transgenic plants showed a larger AsA pool size, lower membrane damage, and a higher level of chlorophyll compared with controls. These data suggested that increasing the plant vitamin C content through enhanced ascorbate recycling could limit the deleterious effects of environmental oxidative stress.
151 citations
TL;DR: Findings indicate a key role for Slc23a1 in renal ascorbate absorption and perinatal survival and reveal regulation of vitamin C biosynthesis in mice.
Abstract: Levels of the necessary nutrient vitamin C (ascorbate) are tightly regulated by intestinal absorption, tissue accumulation, and renal reabsorption and excretion. Ascorbate levels are controlled in part by regulation of transport through at least 2 sodium-dependent transporters: Slc23a1 and Slc23a2 (also known as Svct1 and Svct2, respectively). Previous work indicates that Slc23a2 is essential for viability in mice, but the roles of Slc23a1 for viability and in adult physiology have not been determined. To investigate the contributions of Slc23a1 to plasma and tissue ascorbate concentrations in vivo, we generated Slc23a1-/- mice. Compared with wild-type mice, Slc23a1-/- mice increased ascorbate fractional excretion up to 18-fold. Hepatic portal ascorbate accumulation was nearly abolished, whereas intestinal absorption was marginally affected. Both heterozygous and knockout pups born to Slc23a1-/- dams exhibited approximately 45% perinatal mortality, and this was associated with lower plasma ascorbate concentrations in dams and pups. Perinatal mortality of Slc23a1-/- pups born to Slc23a1-/- dams was prevented by ascorbate supplementation during pregnancy. Taken together, these data indicate that ascorbate provided by the dam influenced perinatal survival. Although Slc23a1-/- mice lost as much as 70% of their ascorbate body stores in urine daily, we observed an unanticipated compensatory increase in ascorbate synthesis. These findings indicate a key role for Slc23a1 in renal ascorbate absorption and perinatal survival and reveal regulation of vitamin C biosynthesis in mice.
137 citations
TL;DR: It is demonstrated that GLUT10 facilitates transport of l-dehydroascorbic acid (DHA), the oxidized form of vitamin C, into mitochondria, and also increases cellular uptake of DHA, which protects cells against oxidative stress, which in turn protects cells from oxidative injury.
Abstract: Mutations in glucose transporter 10 (GLUT10) alter angiogenesis and cause arterial tortuosity syndrome (ATS); however, the mechanisms by which these mutations cause disease remain unclear. It has been reported that in most cells, mitochondria are the major source of reactive oxygen species (ROS). Moreover, mitochondria are known to incorporate as well as recycle vitamin C, which plays a critical role in redox homeostasis, although the molecular mechanism(s) underlying mitochondrial vitamin C uptake are poorly understood. We report here that GLUT10 localizes predominantly to the mitochondria of smooth muscle cells and insulin-stimulated adipocytes, where GLUT10 is highly expressed. We further demonstrate that GLUT10 facilitates transport of l-dehydroascorbic acid (DHA), the oxidized form of vitamin C, into mitochondria, and also increases cellular uptake of DHA, which in turn protects cells against oxidative stress. This protection is compromised when GLUT10 expression in mitochondria is inhibited. In addition, we found that aortic smooth muscle cells from GLUT10-mutant mice have higher ROS levels than those from wild-type mice. Our results identify the physiological role of GLUT10 as the mitochondrial DHA transporter, and demonstrate that GLUT10 protects cells from oxidative injury. Furthermore, our findings provide a mechanism to explain the ascorbate in mitochondria and show how loss-of-function GLUT10 mutations may lead to arterial abnormalities in ATS. These results also reinforce the importance of vitamin C and ROS in degenerative diseases.
122 citations
TL;DR: It is demonstrated that processing crushed broccoli in a temperature range of 30 to 60 degrees C could result in the conversion of l-ASCorbic acid to dehydroascorbic (DHAA), a very important reaction in regard to vitamin C degradation because DHAA could be easily converted to other compounds that do not have the biological activity of vitamin C.
Abstract: UNLABELLED The thermal stability of vitamin C (including l-ascorbic acid [l-AA] and dehydroascorbic acid [DHAA]) in crushed broccoli was evaluated in the temperature range of 30 to 90 degrees C whereas that of ascorbic acid oxidase (AAO) was evaluated in the temperature range of 20 to 95 degrees C. Thermal treatments (for 15 min) of crushed broccoli at 30 to 60 degrees C resulted in conversion of l-AA to DHAA whereas treatments at 70 to 90 degrees C retained vitamin C as l-AA. These observations indicated that enzymes (for example, AAO) could play a major role in the initial phase (that is, oxidation of l-AA to DHAA) of vitamin C degradation in broccoli. Consequently, a study to evaluate the temperature-time conditions that could result in AAO inactivation in broccoli was carried out. In this study, higher AAO activity was observed in broccoli florets than stalks. During thermal treatments for 10 min, AAO in broccoli florets and stalks was stable until around 50 degrees C. A 10-min thermal treatment at 80 degrees C almost completely inactivated AAO in broccoli. AAO inactivation followed 1st order kinetics in the temperature range of 55 to 65 degrees C. Based on this study, a thermal treatment above 70 degrees C is recommended for crushed vegetable products to prevent oxidation of l-AA to DHAA, the onset of vitamin C degradation. PRACTICAL APPLICATION The results reported in this study are applicable for both domestic and industrial processing of vegetables into products such as juices, soups, and purees. In this report, we have demonstrated that processing crushed broccoli in a temperature range of 30 to 60 degrees C could result in the conversion of l-ascorbic acid to dehydroascorbic (DHAA), a very important reaction in regard to vitamin C degradation because DHAA could be easily converted to other compounds that do not have the biological activity of vitamin C.
112 citations
TL;DR: The carotenoids from yellow tamarillo were determined by high-performance liquid chromatography-photodiode array detection/mass spectrometry (HPLC-PDA/MS) as discussed by the authors.
89 citations
TL;DR: HMF would be the optimum indicator of thermal treatment for fruits, and furfural for vegetables, possibly because of greater AA degradation favored by a higher pH in the vegetable samples.
Abstract: The presence of ascorbic acid (AA), vitamin C (AA + dehydroascorbic acid (DHAA)) and furfural as potential precursors of furan in commercial fruit and vegetable jarred baby food was studied. Hydroxymethylfurfural (HMF) was also determined and used, together with furfural levels, as markers of thermal damage. AA, calculated DHAA and vitamin C values ranged between 22.4 and 103, 2.9 and 13.8, and 32.1 and 113.2 mg/100 g, respectively, in fruit-based baby food. However, no trace of AA was found in the vegetable-based baby food samples tested, probably because these samples are not enriched in vitamin C and the content of this vitamin in fresh vegetables is destroyed during processing. Furfural values ranged from not detected to 236 μg/100 g, being higher in vegetable samples than in fruit samples possibly because of greater AA degradation favored by a higher pH in the vegetable samples. HMF values (range: not detected−959 μg/100 g), however, were higher in the fruit samples, probably due to greater carbohydr...
67 citations
TL;DR: Chronic leukaemia patients showed a significant increase in leucocytic H2O2, serum MDA concentration and total anti‐oxidant activity either before or after treatment as compared with control group, and the increase in antioxidant activity in leukaemic patients is not high enough to counteract the harmful effects of free radicals.
Abstract: There is an interactive relationship between leukaemia and oxidative stress. Leukaemic cells produce larger amounts of reactive oxygen species (ROS) than non-leukaemic cells as they are under a continual state of oxidative siege. So, this study was performed on 20 patients with chronic leukaemia from the Oncology Centre, Mansoura University. We measured leucocytic H(2)O(2) concentrations and lipid peroxidation as serum malondialdehyde (MDA) concentration, serum total antioxidant activity, plasma ascorbic acid and dehydroascorbic acid concentrations, blood reduced glutathione concentration, haemolysate G6PD activity, blood catalase activity, serum superoxide dismutase (SOD) activity and serum anti-dsDNA concentration. We found that chronic leukaemia patients showed a significant increase (P < 0.05) in leucocytic H(2)O(2), serum MDA concentration and total antioxidant activity either before or after treatment as compared with control group. Also, there was a significant increase in the other parameters (glutathione, catalase and SOD) either before or after treatment, but we found a significant decrease in ascorbic acid concentration and G6PD activity. There was a significant increase in anti-dsDNA concentration either before or after treatment. It can be concluded that leukaemic patients produce larger amounts of ROS than non-leukaemic patients. Also, the increase in antioxidant activity in leukaemic patients is not high enough to counteract the harmful effects of free radicals. This scenario becomes worse after administration of chemotherapy.
61 citations
TL;DR: Ascorbate acts within microvascular endothelial cells to inhibit septic stimulation of oxidant production by NADPH oxidase and thereby prevents PP2A activation,PP2A-dependent dephosphorylation and redistribution of occludin, and disruption of the endothelial barrier.
60 citations
TL;DR: In this article, the effectiveness of heat inactivation of enzymes e.g., ascorbic acid oxidase (AAO) to stabilise vitamin C during extraction and analysis was evaluated.
59 citations
TL;DR: An improved method is described for assessing DHA in biological samples that provides a useful standard for all DHA determinations and may indicate an important disparity of oxidative stress levels among physiologic sites.
Abstract: Ascorbic acid (AA) has a strong anti-oxidant function evident as its ability to scavenge superoxide radicals in vitro. Moreover, AA is an essential ingredient for post-translational proline hydroxylation of collagen molecules. Dehydroascorbic acid (DHA), the oxidized form of AA, is generated from these reactions. In this study, we describe an improved method for assessing DHA in biological samples. The use of 35 mM tris(2-carboxyethyl)phosphine hydrochloride (TCEP) as a reductant completely reduced DHA to AA after 2 h on ice in a 5% solution of metaphosphoric acid containing 1 mM ethylenediaminetetraacetic acid (EDTA) at pH 1.5. This method enabled us to measure the DHA content in multiple tissues and plasma of 6-weeks-old mice. The percentages of DHA per total AA differed markedly among these tissues, i.e., from 0.8 to 19.5%. The lung, heart, spleen and plasma had the highest levels at more than 10% of DHA per total AA content, whereas the cerebrum, cerebellum, liver, kidney and small intestine had less than 5% of DHA per total AA content. This difference in DHA content may indicate an important disparity of oxidative stress levels among physiologic sites. Therefore, this improved method provides a useful standard for all DHA determinations.
TL;DR: In the AA-depleted hepatocytes from SMP30/GNL KO mice, AA uptake was significantly greater than in matched cultures from wild-type mice, suggesting that intracellular AA is an important regulator of SVCT1 and SVCT2 expression in the liver.
TL;DR: In this paper, the generation of furan from vitamin C during thermal treatment of a starch-based model system, which simulated baby food, was studied and it was shown that increasing the amount of heated sample from 5% to approximately 98% of the total vial volume, drastically reduced furan formation from 70 ppb to 16 ppb.
TL;DR: It is indicated that C48/80 causes oxidative stress in rat adrenal gland through mast cell degranulation.
Abstract: Rats were intraperitoneally treated once with compound 48/80 (C48/80), a mast cell degranulator, (0.75 mg/kg). Serum serotonin, histamine and corticosterone levels increased 0.5 h after C48/80 treatment, but their increases were reduced thereafter. Adrenal total ascorbic acid (ascorbic acid plus dehydroascorbic acid), ascorbic acid and dehydroascorbic acid levels decreased 0.5, 3 or 6 h after C48/80 treatment, adrenal lipid peroxide level increased at 3 and 6 h, adrenal non-protein-SH level decreased at 3 and 6 h and adrenal β-tocopherol level decreased at 3 h. Ketotifen, a mast cell stabilizer (1 mg/kg) administered intraperitoneally at 0.5 h before C48/80 treatment, attenuated all these changes found in the serum and adrenal at 3 h after treatment, while β-tocopherol (250 mg/kg), administered orally at 0.5 h after C48/80 treatment, attenuated all these changes in the adrenal tissue. These results indicate that C48/80 causes oxidative stress in rat adrenal gland through mast cell degranulation.
TL;DR: In this article, the authors hypothesized that cellular uptake of vitamin C as dehydroascorbic acid rather than ascorbic acid would up-regulate antioxidant enzyme systems and impart a protective effect to mitochondria in cells subsequently exposed to lipopolysaccharide (LPS) in an iron free environment.
Abstract: Oxidative stress-induced mitochondrial dysfunction is a common consequence of severe sepsis. However, oxidative stress also activates signalling cascades which enable protection of cells against subsequent oxidative damage. This study hypothesized that cellular uptake of vitamin C as dehydroascorbic acid rather than ascorbic acid would up-regulate antioxidant enzyme systems and impart a protective effect to mitochondria in cells subsequently exposed to lipopolysaccharide (LPS) in an iron free environment. Treatment of monocytes with dehydroascorbic acid, but not ascorbic acid, caused oxidative stress (p< 0.001). Dehydroascorbic acid exposure also resulted in increased manganese superoxide dismutase (p= 0.018) and catalase (p= 0.003) expression. Pre-treatment of monocytes with dehydroascorbic acid followed by LPS resulted in higher mitochondrial membrane potentials than cells without pre-treatment (p< 0.0001). Lower cytochrome c in cytosol (p< 0.05) and higher mitochondrial expression of the anti-a...
TL;DR: Results indicate that the reagent inhibits HSV-1 multiplication after the completion of viral DNA replication, probably at the step of the envelopment of viral nucleocapsids at the Golgi apparatus of infected cells.
Abstract: IN THE PRESENT STUDY, DEHYDROASCORBIC ACID INHIBITED THE MULTIPLICATION OF VIRUSES OF THREE DIFFERENT FAMILIES: herpes simplex virus type 1 (HSV-1), influenza virus type A and poliovirus type 1 Although dehydroascorbic acid showed some cytotoxicity at higher concentrations, the observed antiviral activity was not the secondary result of the cytotoxic effect of the reagent, as the inhibition of virus multiplication was observed at reagent concentrations significantly lower than those resulting in cytotoxicity Characterization of the mode of the antiviral action of dehydroascorbic acid against HSV-1 revealed that the addition of reagent at any time post infection inhibited the formation of progeny infectious virus in the infected cells, and a one-step growth curve showed that the addition of reagent allowed formation for an additional 2 h, but then almost completely suppressed it These results indicate that the reagent inhibits HSV-1 multiplication after the completion of viral DNA replication, probably at the step of the envelopment of viral nucleocapsids at the Golgi apparatus of infected cells
TL;DR: Results indicate that pre-administered AA protects against oxidative damage in the liver of rats with WIRS possibly by attenuating disruption of the antioxidant defense system and increases in NO generation and neutrophil infiltration in the tissue.
Abstract: We examined whether L-ascorbic acid (AA) (or reduced ascorbic acid) protects against oxidative damage in the liver of rats subjected to water-immersion stress (WIRS). AA (100, 250 or 500 mg/kg) was orally administered at 0.5 h before the onset of WIRS. Rats with 6 h of WIRS had increased serum corticosterone, glucose, total ascorbic acid (T-AA), AA, lipid peroxide (LPO), and NOx concentrations and alanine aminotransferase and aspartate aminotrasferase activities. The stressed rats had increased hepatic LPO, NOx, and dehydroascorbic acid concentrations and myeloperoxidase activity, decreased hepatic T-AA, AA, reduced glutathione concentrations and superoxide dismutase activity, and unchanged hepatic vitamin E concentration. Pre-administered AA attenuated the stress-induced changes in serum LPO and NOx concentrations and alanine aminotransferase and aspartate aminotrasferase activities and hepatic LPO, NOx, and T-AA, AA, dehydroascorbic acid, and reduced glutathione concentrations and myeloperoxidase and superoxide dismutase activities dose-dependently. Pre-administered AA did not affect the stress-induced changes in serum corticosterone and glucose concentrations. These results indicate that pre-administered AA protects against oxidative damage in the liver of rats with WIRS possibly by attenuating disruption of the antioxidant defense system and increases in NO generation and neutrophil infiltration in the tissue.
TL;DR: In this article, a differential pulse polarographic (DPP) method was developed for the determination of ascorbic acid and dehydroascorbic acid (DHA), the two main forms of Vitamin C. Results using the proposed method correlated well with those obtained by two reference methodologies: the common iodometric method and a published chromatographic methodology.
Abstract: A differential pulse polarographic (DPP) method has been developed for the determination of ascorbic acid (AA) and dehydroascorbic acid (DHA), the two main forms of Vitamin C. The method consists of the DPP analysis of a quinoxaline obtained by the derivatization of DHA with o -phenylenediamine. Results using the proposed method correlated well with those obtained by two reference methodologies: the common iodometric method and a published chromatographic methodology. It was also used in the study of Vitamin C degradation in fruit juices, showing that it involves an initial oxidation of AA to DHA, followed by hydrolytic degradation of the latter.
TL;DR: An electroanalytical strategy for simultaneous determination of ascorbic acid and dehydroascorbic acid (DHA) is described in this article, where a palladized Al electrode is used for hydrodynamic amperometry of AA, while the decrease of anodic stripping voltammetry current of the K2UO2[Fe(CN)6]-Pd/Al electrode prepared in the presence of DHA was the principal of the DHA determination.
Abstract: An electroanalytical strategy for the simultaneous determination of ascorbic acid (AA) and dehydroascorbic acid (DHA), is described. A palladized Al electrode is used for hydrodynamic amperometry of AA. While the decrease of anodic stripping voltammetry current of the K2UO2[Fe(CN)6]-Pd/Al electrode prepared in the presence of DHA was the principal of the DHA determination. The calibration graph for both methods was linear over the concentration range 1 – 50 mM. The detection limit was found to be 0.5 mM. Some fresh fruit juices and vegetables of trace level of AA and DHA were analyzed as the typical example of application.
01 Jan 2010
TL;DR: A number of drug substances and their formulated products including ascorbic acid may degrade on exposure to light and appropriate precautions are to be taken to preserve the active ingredients as raw material and in dosage forms as discussed by the authors.
Abstract: A number of drug substances and their formulated products including ascorbic acid may degrade on exposure to light and appropriate precautions are to be taken to preserve the active ingredients as raw material and in dosage forms. Ascorbic acid solutions on UV irradiation are degraded to dehydroascorbic acid and further photoproducts including 2,3-diketo-L-gulonic acid, oxalic acid and L-theoronic acid. Pharmaceutical formulations containing ascorbic acid have been stabilized by using antioxidants, DL-methionine, mannitol, sorbitol, sucrose, dextrose, halide salts, triplet quenchers, metal-complexing agents and viscosity enhancing agents.
TL;DR: Methods have been developed to assess the ability of intact cells to recycle ascorbate and to generate intracellular reducing equivalents required to maintain the redox status of the cells.
Abstract: Most mammalian cells cannot synthesize vitamin C, or ascorbic acid, and thus must have efficient mechanisms for its intracellular recycling. Ascorbate can be recycled from both its oxidized forms using electrons from several intracellular reducing co-factors, including GSH and the reduced pyridine nucleotides. Methods have been developed to assess the ability of intact cells to recycle ascorbate, which include assay of extracellular ferricyanide reduction and measurement of the ability of the cells to reduce dehydroascorbic acid to ascorbate. Lipoic acid, a disulfide containing medium chain fatty acid, is also taken up by cells and reduced to dihydrolipoic acid, which can be measured upon efflux from the cells using Ellman's reagent. Together, these assays provide an estimate of the ability of different cell types to recycle ascorbate and to generate intracellular reducing equivalents required to maintain the redox status of the cells.
Patent•
25 May 2010
TL;DR: In this article, stable liquid compositions containing the oxidized form of vitamin C known as dehydroascorbic acid (DHAA) were described, which are useful as dietary supplements, skin-enhancers, concentrates, or research solutions.
Abstract: The invention relates to stable liquid compositions containing the oxidized form of vitamin C known as dehydroascorbic acid (DHAA). The compositions comprise DHAA and a pharmacologically acceptable liquid organic polyol solvent. The polyol solvent comprises about 50% or greater of the total weight of the composition. The compositions are useful as dietary supplements, skin-enhancers, concentrates, or research solutions.
Patent•
18 Mar 2010
TL;DR: In this paper, a dehydroascorbic acid reductase activity promoter of high biostability, obtained through seeking a component having dehydroasorbic aceric acid reductionase activity-promoting effect in plant extract, enabling to improve the sustainability of the enhancement and effect of ascorbic acid's physiological activity in a biological tissue and various organs via regeneration, was provided.
Abstract: PROBLEM TO BE SOLVED: To provide a dehydroascorbic acid reductase activity promoter of high biostability, obtained through seeking a component having dehydroascorbic acid reductase activity-promoting effect in plant extract, enabling to improve the sustainability of the enhancement and effect of ascorbic acid's physiological activity in a biological tissue and various organs via ascorbic acid regeneration when applied to a living body, and free from any possibility of adversely affecting a living body, and to provide a composition containing the promoter. SOLUTION: The dehydroascorbic acid reductase activity promoter includes, as the active ingredient, an extract of a plant belonging to the genus Tabebuia sp., Bignoniaceae family. The composition containing the promoter is also provided. COPYRIGHT: (C)2010,JPO&INPIT
Patent•
11 Jan 2010TL;DR: In this article, the authors formulated a set of ingredients for artificially coloring the skin, formulated into a physiologically acceptable medium, including at least dehydroascorbic acid and a monomeric derivative and/or isomeric form and polymeric derivative thereof, and at least one preferably monocarbonyl or polycarbonyl self-tanning agent.
Abstract: Cosmetic compositions for artificially coloring the skin contain, formulated into a physiologically acceptable medium,
a) at least dehydroascorbic acid and/or a monomeric derivative and/or isomeric form and/or polymeric derivative thereof, and b) at least one preferably monocarbonyl or polycarbonyl self-tanning agent;
the dehydroascorbic acid may be formed “in situ” from ascorbic acid or a derivative thereof or a salt thereof via chemical oxidation and/or via enzymatic oxidation.
TL;DR: A survey of 33 ascorbylated natural products and their reported biological activities can be found in this paper, where ascorbigens from Brassica species are ascorlated indole derivatives, and some of these compounds are formed either as a result of nucleophilic substitution or addition by ascorbate.
Abstract: While ascorbic acid (vitamin C) is mostly known as a cofactor for proline hydroxylase and as a biological antioxidant, it also forms covalent bonds with natural products which we here refer to as 'ascorbylation'. A number of natural products containing an ascorbate moiety has been isolated and characterized from a variety of biological sources, ranging from marine algae to flowering plants. Most of these compounds are formed either as a result of nucleophilic substitution or addition by ascorbate, e.g. the ascorbigens from Brassica species are ascorbylated indole derivatives. Some ascorbylated tannins appear to be formed from electrophilic addition to dehydroascorbic acid. There are also examples of annulations of ascorbate with dietary polyphenols, e.g. epigallocatechin gallate (EGCG) and resveratrol derivatives. Herein is a survey of 33 ascorbylated natural products and their reported biological activities.
01 Jan 2010
TL;DR: In this article, the strawberry cultivars Arosa, Clery, Miss, Raurica, Queen Elisa, Diamante and Madeleine were harvested at the commercially maturity stage and the content of total ascorbic acid and dehydroascorbic acid (DHA) was determined.
Abstract: The strawberry cultivars Arosa, Clery, Miss, Raurica, Queen Elisa, Diamante and Madeleine grown in Slovenia were harvested at the commercially maturity stage and the content of total ascorbic acid and dehydroascorbic acid (DHA) was determined. Ascorbic acid (AA) was measured by using high-performance liquid chromatography and photodiode array detector. The total AA content of cultivars ranged from 32.3 mg/100 g to 62.5 mg/100 g. No significant difference in total AA contents was observed in fresh and freeze-dried samples.