Use Of Ascorbate Research Articles

Air Tolerant Cadiot-Chodkiewicz and Sonogashira Cross-Couplings.

Cadiot-Chodkiewicz cross-couplings generate an unsymmetric buta-1,3-diyne by way of a Cu(I)-catalyzed coupling between a terminal alkyne and a 1-haloalkyne. Despite their widespread use, Cadiot-Chodkiewicz reactions are plagued by the generation of symmetric buta-1,3-diyne side products, formed through competing: (a) formal reductive homo-coupling of the 1-haloalkyne and (b) oxidative (Glaser-Hay/Eglinton) homo-coupling of the terminal alkyne. To overcome this issue, a large excess of one of the two reacting alkynes is commonly deployed, and difficult separations of cross- and homo-coupled products are often encountered. Here, we demonstrate that the use of ascorbate as a reductant leads to a suppression of these unwanted side reactions, hence permitting excellent yields with a roughly stoichiometric ratio of reactants. The procedure also avoids an inert gas atmosphere and uses a sustainable solvent. A similar approach is effective for cross-couplings involving a Pd(0)/Pd(II) catalytic cycle, with air tolerant Sonogashira couplings also established.

The Anti-Leukemia Effect of Ascorbic Acid: From the Pro-Oxidant Potential to the Epigenetic Role in Acute Myeloid Leukemia.

Data derived from high-throughput sequencing technologies have allowed a deeper understanding of the molecular landscape of Acute Myeloid Leukemia (AML), paving the way for the development of novel therapeutic options, with a higher efficacy and a lower toxicity than conventional chemotherapy. In the antileukemia drug development scenario, ascorbic acid, a natural compound also known as Vitamin C, has emerged for its potential anti-proliferative and pro-apoptotic activities on leukemic cells. However, the role of ascorbic acid (vitamin C) in the treatment of AML has been debated for decades. Mechanistic insight into its role in many biological processes and, especially, in epigenetic regulation has provided the rationale for the use of this agent as a novel anti-leukemia therapy in AML. Acting as a co-factor for 2-oxoglutarate-dependent dioxygenases (2-OGDDs), ascorbic acid is involved in the epigenetic regulations through the control of TET (ten-eleven translocation) enzymes, epigenetic master regulators with a critical role in aberrant hematopoiesis and leukemogenesis. In line with this discovery, great interest has been emerging for the clinical testing of this drug targeting leukemia epigenome. Besides its role in epigenetics, ascorbic acid is also a pivotal regulator of many physiological processes in human, particularly in the antioxidant cellular response, being able to scavenge reactive oxygen species (ROS) to prevent DNA damage and other effects involved in cancer transformation. Thus, for this wide spectrum of biological activities, ascorbic acid possesses some pharmacologic properties attractive for anti-leukemia therapy. The present review outlines the evidence and mechanism of ascorbic acid in leukemogenesis and its therapeutic potential in AML. With the growing evidence derived from the literature on situations in which the use of ascorbate may be beneficial in vitro and in vivo, we will finally discuss how these insights could be included into the rational design of future clinical trials.

EFFECTS OF BLACK PEPPER AND SODIUM ASCORBATE ON VOLATILE COMPOUNDS OF SUCUK

The effects of different levels of black pepper (5, 10 or 15 g/kg) and the use of ascorbate (without ascorbate and with ascorbate) on the volatile compounds of sucuk were examined in the study. The volatile compounds of the samples belonging to each group were extracted by solid phase micro-extraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). Ascorbate was not effective on aldehydes, aromatic hydrocarbons, esters, acids and terpenes. While high black pepper level (15 g/kg) decreased the abundance of hexanal, it increased the ethanol abundance. α -pinene and 3-carene increased as black pepper levels increased. Among the terpenes, D-limonene and caryophyllene were the most abundant compounds and were significantly affected by the black pepper level of 15 g/kg. D-limonene and caryophyllene were the most related compounds for PC1; while allyl mercaptane, γ-terpinene, D-limonene, hexane for PC2.

In vitro and in vivo digestion of red cured cooked meat: oxidation, intestinal microbiota and fecal metabolites

Mechanisms explaining epidemiological associations between red (processed) meat consumption and chronic disease risk are not yet elucidated, but may involve oxidative reactions, microbial composition alterations, inflammation and/or the formation of toxic bacterial metabolites. First, in vitro gastrointestinal digestion of 23 cooked beef-lard minces, to which varying doses of nitrite salt (range 0–40 g/kg) and sodium ascorbate (range 0–2 g/kg) were added, showed that nitrite salt decreased protein carbonylation up to 3-fold, and inhibited lipid oxidation, demonstrated by up to 4-fold lower levels of ‘thiobarbituric acid reactive substances’, 32-fold lower 4-hydroxynonenal, and 21-fold lower hexanal values. The use of ascorbate increased the antioxidant effect of low nitrite salt levels, whereas it slightly increased protein carbonylation at higher doses of nitrite salt. The addition of a low dose of ascorbate without nitrite salt slightly promoted oxidation during digestion, whereas higher doses had varying antioxidant effects. Second, 40 rats were fed a diet of cooked chicken- or beef-lard minces, either or not cured, for three weeks. Beef, compared to chicken, consumption increased lipid oxidation (2- to 4-fold) during digestion, and gut protein fermentation (cecal iso-butyrate, (iso-)valerate, and fecal indole, cresol), but oxidative stress and inflammation were generally not affected. Cured, compared to fresh, meat consumption significantly increased stomach protein carbonylation (+16%), colonic Ruminococcaceae (2.1-fold) and cecal propionate (+18%), whereas it decreased cecal butyrate (-25%), fecal phenol (-69%) and dimethyl disulfide (-61%) levels. Fecal acetaldehyde and diacetyl levels were increased in beef-fed rats by 2.8-fold and 5.9-fold respectively, and fecal carbon disulfide was 4-fold higher in rats consuming cured beef vs. fresh chicken. Given their known toxicity, the role of acetaldehyde and carbon disulfide in the relation between meat consumption and health should be investigated in future studies.

Trying to Solve the Puzzle of the Interaction of Ascorbic Acid and Iron: Redox, Chelation and Therapeutic Implications

Iron and ascorbic acid (vitamin C) are essential nutrients for the normal growth and development of humans, and their deficiency can result in serious diseases. Their interaction is of nutritional, physiological, pharmacological and toxicological interest, with major implications in health and disease. Millions of people are using pharmaceutical and nutraceutical preparations of these two nutrients, including ferrous ascorbate for the treatment of iron deficiency anaemia and ascorbate combination with deferoxamine for increasing iron excretion in iron overload. The main function and use of vitamin C is its antioxidant activity against reactive oxygen species, which are implicated in many diseases of free radical pathology, including biomolecular-, cellular- and tissue damage-related diseases, as well as cancer and ageing. Ascorbic acid and its metabolites, including the ascorbate anion and oxalate, have metal binding capacity and bind iron, copper and other metals. The biological roles of ascorbate as a vitamin are affected by metal complexation, in particular following binding with iron and copper. Ascorbate forms a complex with Fe3+ followed by reduction to Fe2+, which may potentiate free radical production. The biological and clinical activities of iron, ascorbate and the ascorbate–iron complex can also be affected by many nutrients and pharmaceutical preparations. Optimal therapeutic strategies of improved efficacy and lower toxicity could be designed for the use of ascorbate, iron and the iron–ascorbate complex in different clinical conditions based on their absorption, distribution, metabolism, excretion, toxicity (ADMET), pharmacokinetic, redox and other properties. Similar strategies could also be designed in relation to their interactions with food components and pharmaceuticals, as well as in relation to other aspects concerning personalized medicine.

Nitrosamine formation in a semi-dry fermented sausage: Effects of nitrite, ascorbate and starter culture and role of cooking

In this study, effects of ingoing nitrite level (0, 50, 100 and 150 mg/kg), use of sodium ascorbate, addition of starter culture (Lactobacillus plantarum GM77 + Staphylococcus xylosus GM92) and cooking level (control, medium, medium well, well done and very well done) on nitrosamine formation in heat-treated sucuk, a type of semi-dry fermented sausage, were investigated. The use of ascorbate had no significant effect on NDMA (N-Nitrosodimethylamine) and NPIP (N-Nitrosopiperidine) contents in the presence of starter culture. A higher NPYR (N- Nitrosopyrrolidine) content was detected in the group with starter culture at 150 mg/kg nitrite level in comparison to the group without starter culture. Cooking level affected all identified nitrosamines very significantly. Ingoing nitrite level × cooking level interaction was only effective on NPIP and advanced cooking levels (well done and very well done) at higher ingoing nitrite levels (100 and 150 mg/kg) resulted in significant increases in NPIP content.

High doses of sodium ascorbate act as a prooxidant and protect gnotobiotic brine shrimp larvae (Artemia franciscana) against Vibrio harveyi infection coinciding with heat shock protein 70 activation

Ascorbate is an essential nutrient commonly regarded as an antioxidant. In this study, using axenic brine shrimp and pathogenic strain Vibrio harveyi as the host-pathogen model, we confirmed that pretreatment of sodium ascorbate (NaAs), at an optimum concentration, was a prooxidant by generation of hydrogen peroxide, inducing protective effects in the brine shrimp against V. harveyi infection. Such a protective effect could be neutralized by the addition of an antioxidant enzyme catalase. We further showed that generation of oxygen radicals is linked to the induction of heat shock protein 70 (Hsp70), which is involved in eliciting the antioxidant protection system including superoxidase dismutase (SOD) and possibly many other immune responses. Furthermore, using RNA interference technique, we found that the pretreatment of sodium ascorbate increased the survival significantly in the control knockdown groups (using green fluorescent protein, GFP) but not in Hsp70 knockdown groups and the result directly suggested that the up-regulated Hsp70 induced by sodium ascorbate pretreatment induced the protective effect. These results provide a mechanistic rationale for exploring the further use of ascorbate for antimicrobial therapy in aquaculture.

Evaluación de la eficacia del ascorbato de sodio en diferentes concentraciones y tiempos en tratamientos adhesivos sobre esmalte de dientes aclarados. Análisis in vitro mediante pruebas de cizallamiento

Se ha reportado que las restauraciones adhesivas tras el aclaramiento dental, sufren una notable pérdida de resistencia a las fuerzas producidas por la masticación, razón por la cual la literatura recomienda esperar 15 días para realizar procedimientos adhesivos. Por este motivo el propósito de este estudio fue evaluar la eficacia del ascorbato de sodio como un agente que permita reducir el tiempo de espera de procedimientos adhesivos posteriores al aclaramiento. Se utilizaron 103 dientes bovinos, a los cuales se les seccionó la corona clínica y se colocó en cubos acrílicos. Los cuerpos de prueba se dividieron en 5 grupos los cuales fueron sometidos a aclaramiento con peróxido de hidrógeno al 40% en dos aplicaciones de 20 minutos cada una y un grupo control positivo donde no se realizó aclaramiento. Grupo No. 1: tratado con ascorbato de sodio al 10% por 10 minutos. Grupo No. 2: Ascorbato de sodio al 10% por 5 minutos. Grupo No. 3: Ascorbato de sodio al 5% por 10 minutos. Grupo No. 4: Ascorbato de sodio al 5% por 5 minutos. Y finalmente un grupo control negativo donde luego del aclaramiento no se colocó ascorbato de sodio e inmediatamente después del aclaramiento se hizo el proceso adhesivo. Los especímenes fueron sometidos a pruebas de cizallamiento. Los resultados fueron sujetos a análisis de ANOVA y reportaron que los grupos sometidos a aclaramiento presentaron una reducción en la fuerza de adhesión en relación al grupo control positivo, a pesar de la aplicación del ascorbato de sodio.

Ascorbate as a co-factor for fe- and 2-oxoglutarate dependent dioxygenases: physiological activity in tumor growth and progression.

Ascorbate is a specific co-factor for a large family of enzymes known as the Fe- and 2-oxoglutarate-dependent dioxygenases. These enzymes are found throughout biology and catalyze the addition of a hydroxyl group to various substrates. The proline hydroxylase that is involved in collagen maturation is well known, but in recent times many new enzymes and functions have been uncovered, including those involved in epigenetic control and hypoxia-inducible factor (HIF) regulation. These discoveries have provided crucial mechanistic insights into how ascorbate may affect tumor biology. In particular, there is growing evidence that HIF-1-dependent tumor progression may be inhibited by increasing tumor ascorbate levels. However, rigorous clinical intervention studies are lacking. This review will explore the physiological role of ascorbate as an enzyme co-factor and how this mechanism relates to cancer biology and treatment. The use of ascorbate in cancer should be informed by clinical studies based on such mechanistic hypotheses.

High-Dose Parenteral Ascorbate Enhanced Chemosensitivity of Ovarian Cancer and Reduced Toxicity of Chemotherapy

Ascorbate (vitamin C) was an early, unorthodox therapy for cancer, with an outstanding safety profile and anecdotal clinical benefit. Because oral ascorbate was ineffective in two cancer clinical trials, ascorbate was abandoned by conventional oncology but continued to be used in complementary and alternative medicine. Recent studies provide rationale for reexamining ascorbate treatment. Because of marked pharmacokinetic differences, intravenous, but not oral, ascorbate produces millimolar concentrations both in blood and in tissues, killing cancer cells without harming normal tissues. In the interstitial fluid surrounding tumor cells, millimolar concentrations of ascorbate exert local pro-oxidant effects by mediating hydrogen peroxide (H(2)O(2)) formation, which kills cancer cells. We investigated downstream mechanisms of ascorbate-induced cell death. Data show that millimolar ascorbate, acting as a pro-oxidant, induced DNA damage and depleted cellular adenosine triphosphate (ATP), activated the ataxia telangiectasia mutated (ATM)/adenosine monophosphate-activated protein kinase (AMPK) pathway, and resulted in mammalian target of rapamycin (mTOR) inhibition and death in ovarian cancer cells. The combination of parenteral ascorbate with the conventional chemotherapeutic agents carboplatin and paclitaxel synergistically inhibited ovarian cancer in mouse models and reduced chemotherapy-associated toxicity in patients with ovarian cancer. On the basis of its potential benefit and minimal toxicity, examination of intravenous ascorbate in combination with standard chemotherapy is justified in larger clinical trials.

Future climate alleviates stress impact on grassland productivity through altered antioxidant capacity

Predicting future ecosystem functioning requires a mechanistic understanding of how plants cope with different stressors under future climate conditions with elevated CO2 concentrations and warmer temperatures. Nonetheless, studies of stress responses under combined elevated CO2 and warming remain scarce.We assembled grassland communities in sunlit, climate-controlled greenhouses and subjected these to three stressors (drought, zinc toxicity, nitrogen limitation) and their combinations. Half of the communities were exposed to ambient climate conditions (current climate) and the other half were continuously kept at 3°C above ambient temperatures and at 620ppm CO2 (future climate).Across all stressors and their combinations, future climate-grown plants coped better with stress, i.e. above-ground biomass production was reduced less in future than in current climate. Among several tested potential biochemical and ecophysiological stress-relief mechanisms, we found three mutually non-exclusive mechanisms underpinning an improved stress protection under future climate conditions: (i) altered sugar metabolism; (ii) up-regulated levels of total antioxidant capacity and polyphenols; and (iii) more efficient use of ascorbate and glutathione as antioxidants.

Parenteral Ascorbate As a Cancer Therapeutic: A Reassessment Based on Pharmacokinetics

Ewan Cameron reported that ascorbate, given orally and intravenously at doses of up to 10 g/day, was effective in the treatment of cancer. Double-blind placebo-controlled clinical trials showed no survival advantage when the same doses of ascorbate were given orally, leading the medical and scientific communities to dismiss the use of ascorbate as a potential cancer treatment. However, the route of administration results in major differences in ascorbate bioavailability. Tissue and plasma concentrations are tightly controlled in response to oral administration, but this can be bypassed by intravenous administration. These data provide a plausible scientific rationale for the absence of a response to orally administered ascorbate in the Mayo clinic trials and indicate the need to reassess ascorbate as a cancer therapeutic. High dose ascorbate is selectively cytotoxic to cancer cell lines through the generation of extracellular hydrogen peroxide (H2O2). Murine xenograft models confirm a growth inhibitory effect of pharmacological concentrations. The safety of intravenous ascorbate has been verified in encouraging pilot clinical studies. Neither the selective toxicity of pharmacologic ascorbate against cancer cells nor the mechanism of H2O2-mediated cytotoxicity is fully understood. Despite promising preclinical data, the question of clinical efficacy remains. A full delineation of mechanism is of interest because it may indicate susceptible cancer types. Effects of pharmacologic ascorbate used in combination with standard treatments need to be defined. Most importantly, the clinical efficacy of ascorbate needs to be reassessed using proper dosing, route of administration, and controls.

The use of ascorbate as an oxidation inhibitor in prebiotic amino acid synthesis: a cautionary note.

It is generally thought that the terrestrial atmosphere at the time of the origin of life was CO(2)-rich and that organic compounds such as amino acids would not have been efficiently formed abiotically under such conditions. It has been pointed out, however, that the previously reported low yields of amino acids may have been partially due to oxidation by nitrite/nitrate during acid hydrolysis. Specifically, the yield of amino acids was found to have increased significantly (by a factor of several hundred) after acid hydrolysis with ascorbic acid as an oxidation inhibitor. However, it has not been shown that CO(2) was the carbon source for the formation of the amino acids detected after acid hydrolysis with ascorbic acid. We therefore reinvestigated the prebiotic synthesis of amino acids in a CO(2)-rich atmosphere using an isotope labeling experiment. Herein, we report that ascorbic acid does not behave as an appropriate oxidation inhibitor, because it contributes amino acid contaminants as a consequence of its reactions with the nitrogen containing species and formic acid produced during the spark discharge experiment. Thus, amino acids are not efficiently formed from a CO(2)-rich atmosphere under the conditions studied.

Metal accumulation and response of antioxidant enzymes in seedlings and adult sunflower mutants with improved metal removal traits on a metal-contaminated soil

Sunflower mutant lines with an enhanced tolerance and metal accumulation capacity obtained by mutation breeding have been proposed for Zn, Cd and Cu removal from metal-contaminated soils in previous studies. However, soils contaminated with trace elements induce various biochemical alterations in plants leading to oxidative stress. There is a lack of knowledge concerning the metal accumulation and antioxidant responses during the growth and development of sunflowers. This study, therefore, aimed to characterise metal accumulation and possible metal detoxification mechanisms in young seedlings and adult sunflowers. Beside the inbred line, two mutant lines with an improved growth and enhanced metal uptake capacity on a metal contaminated soil were investigated in more detail. Sunflowers cultivated on a metal-contaminated soil in the greenhouse showed a decrease in shoot biomass and chlorophyll concentration in two different developmental stages. Adult sunflowers showed a lower sensitivity to metal toxicity than young seedlings, whereas mutant lines were more tolerant to metal stress than the control. Mutant lines also produced a higher amount of carotenoids on a metal-contaminated soil than on the control soil, indicating a possible protective mechanism of sunflower mutants against oxidative stress caused by Cd and excess Zn. Heavy metals primarily increased the activity of antioxidant enzymes involved in the ascorbate–glutathione cycle in sunflower leaves. Activity of dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR) was strongly increased in young seedlings exposed to heavy metals. The enzyme activities were even more pronounced in mutant lines. A significantly increased ascorbate peroxidase (APOX) activity in adult sunflowers exposed to heavy metals indicated an elevated use of ascorbate after a longer exposure to metal stress. An increased antioxidant level corresponded to a high Cd and Zn accumulation in young and adult sunflowers. Metal distribution, zinc translocation in particular, from the root into the shoot tissue obviously increased during sunflower growth and ripening. Altogether, these results suggest that sunflower plants, primarily the mutant lines, possess an efficient defence mechanism against oxidative stress caused by metal toxicity. A good tolerance of sunflowers toward heavy metals coupled with an increased metal accumulation capacity might contribute to an efficient removal of heavy metals from a polluted area.

Intravenous ascorbic acid to prevent and treat cancer-associated sepsis?

The history of ascorbic acid (AA) and cancer has been marked with controversy. Clinical studies evaluating AA in cancer outcome continue to the present day. However, the wealth of data suggesting that AA may be highly beneficial in addressing cancer-associated inflammation, particularly progression to systemic inflammatory response syndrome (SIRS) and multi organ failure (MOF), has been largely overlooked. Patients with advanced cancer are generally deficient in AA. Once these patients develop septic symptoms, a further decrease in ascorbic acid levels occurs. Given the known role of ascorbate in: a) maintaining endothelial and suppression of inflammatory markers; b) protection from sepsis in animal models; and c) direct antineoplastic effects, we propose the use of ascorbate as an adjuvant to existing modalities in the treatment and prevention of cancer-associated sepsis.

Different roles of radical scavengers – ascorbate and urate in the cerebrospinal fluid of amyotrophic lateral sclerosis patients

Ferrous iron, released from iron deposits in the motor cortex and other brain regions of amyotrophic lateral sclerosis (ALS) patients, participates in the Fenton reaction in cerebrospinal fluid (CSF) alongside H2O2, which is continuously released by neuronal cells. In vivo, the production of notoriously reactive hydroxyl radicals via this reaction could lead to the progression of the disease. Herein, we have examined the effect of ascorbate and uric acid on the production of hydroxyl radicals in CSF from both sporadic ALS patients and control subjects. Electron paramagnetic resonance spectroscopy identified ascorbyl radicals in CSF from ALS patients whereas it was undetectable in control CSF. The addition of H2O2 to the CSF from ALS patients provoked further formation of ascorbyl radicals and the formation of hydroxyl radicals ex vivo. The hydroxyl addition of uric acid to CSF from ALS patients diminished the production of hydroxyl radicals. In conclusion, there are clear differences between the roles of the two examined radical scavengers in the CSF of ALS patients indicating that the use of ascorbate could have unfavourable effects in ALS patients.

Catalytic Therapy of Cancer with Ascorbate and Extracts of Medicinal Herbs

Catalytic therapy (CT) is a cancer treatment modality based on the generation of reactive oxygen species (ROS) using a combination of substrate molecules and a catalyst. The most frequently used substrate/catalyst pair is ascorbate/Co phthalocyanine (PcCo). In the present work, herb extracts containing pigments have been studied as a catalyst in place of PcCo. Extracts from herbs are expected to have efficiency comparable with that of phthalocyanines but as natural products, to exhibit fewer side effects. The present studies demonstrate that a combined use of ascorbate and herbal extracts results in ROS production and a significant decrease in the number of cancer cells after a single in vitro treatment. Treatment with ascorbate in conjunction with extracts prepared from several medicinal herbs stimulated apoptosis and disrupted the cell cycle. The number of cells accumulating in the sub-G0/G1 stage of the cell cycle was increased 2- to 7-fold, and cells in G2/M increased 1.5- to 20-fold, indicating that the treatment protocol was highly effective in suppressing DNA synthesis and potentially reflecting DNA damage in the tumor cells. In addition, 20–40% of the cells underwent apoptosis within 24 h of completing treatment. Our results suggest that herbal extracts can function as CT catalysts in the treatment of cancer.

Catalytic therapy of cancer with porphyrins and ascorbate

Catalytic therapy (CT) is a cancer treatment modality based on the generation of reactive oxygen species (ROS) using a combination of substrate molecules and a catalyst. The most frequently used substrate and catalyst pair is ascorbate/Co phthalocyanine (PcCo). In the present study, porphyrins containing transition metal ions as catalysts in place of PcCo were studied. Porphyrins that are expected to be as efficient as phthalocyanines, but may have fewer side effects, were analyzed. ROS production through the combined use of ascorbate and porphyrins decreased the number of breast cancer tumor cells by 20–40% after a single in vitro treatment, as compared to control cells. Treatment with ascorbate in conjunction with porphyrins stimulated apoptosis and disrupted the cell cycle. These treatments enhanced apoptosis by 20–40% when compared to treatments with ascorbate and porphyrins. In addition, the number of cells accumulating in the sub G0/G1 stage of the cell cycle increased from 3- to 10-fold, potentially reflecting that the treatment was highly effective in inducing DNA damage in the tumor cells, suggesting that porphyrins may be beneficial as a CT catalyst in the treatment of cancer.

EFFECT OF WHEY PROTEIN-BEESWAX EDIBLE COMPOSITE COATING ON COLOR CHANGE OF FRESH-CUT PERSIMMONS CV. ´ROJO BRILLANTE´

Edible composite coatings were prepared from whey protein concentrate (WPC) and beeswax (BW). Sodium ascorbate at 0%, 0.5%, 1% and 1.5% content was incorporated in the formulations as antioxidants. Persimmons were dip-coated either in the WPC-BW-Ascorbate coatings or in ascorbate solutions at 0.5%, 1% and 1.5% content. Finally, samples were stored 8 days at 5°C in open or sealed trays. Texture, weight loss and color (CIE L*a*b*, and browning index) were measured during storage. Coating application improved texture and reduced weight loss compared to the control and ascorbate-dipped samples in open conditions. However, when samples remained closed, coatings did not improve texture and weight loss. The use of ascorbate increased L*, and reduced browning index compared to the control. Application of the coatings significantly reduced browning of the fresh-cut persimmons compared to the application of ascorbate solutions alone. Ascorbate concentrations above 1% did not further reduce browning of WPC-BW-based coated persimmons. These results indicate that WPC-BW-Ascorbate coatings are effective reducing browning, weight loss and texture loss of fresh-cut persimmons compared to the use of ascorbate alone.

Molecular shuttle chelation: the use of ascorbate, desferrioxamine and Feralex-G in combination to remove nuclear bound aluminum.

1. Abundant data suggest that aluminum (Al(III)) exposure may be an environmental risk factor contributing to the development, progression and/or neuropathology of several human neurodegenerative disorders, including Alzheimer's disease (AD). 2. Nuclei appear to be one directed target for Al(III) binding, accumulation, and Al(III)-mediated dysfunction due in part to their high content of polyphosphorylated nucleic acids, nucleotides, and nucleoproteins. 3. The design of chelation therapies dealing with the removal of Al(III) from these genetic compartments therefore represents an attractive strategy to alleviate the development and/or progression of central nervous system dysfunction that may arise from excessive Al(III) exposure. 4. In this study we have investigated the potential application of 10 natural and synthetic Al(III) chelators, including ascorbate (AS), desferrioxamine (DF), and Feralex-G (FG), used either alone or in combination, to remove Al(III) preincubated with intact human brain cell nuclei. 5. Although nuclear bound Al(III) was found to be highly refractory to removal, the combination of AS+FG was found to be particularly effective in removing Al(III) from the nuclear matrix. 6. Our data suggest that chelators carrying cis-hydroxy ketone groups, such as FG, are particularly suited to the removal of Al(III) from complex biological systems. 7. We further suggest a mechanism whereby small chelating molecules may penetrate the nucleus, bind Al(III), diffuse to regions accessible by the larger DF or FG molecules and transfer their Al(III) to DF or FG. 8. The proposed mechanism, called molecular shuttle chelation may provide a useful pharmacotherapy in the potential treatment of Al(III) overload disease.