Vitamin C is synthesized by almost all animals. However, for humans, it is a vitamin that needs constant replenishment in the diet. While its role as an anti-oxidant and for preventing scurvy have ...been known for a long time, novel functions and unrecognized associations continue to be identified for this enigmatic molecule. In the past decade, new details have emerged regarding differences in its uptake by oral and intravenous modes. While vitamin C deficiency remains largely unknown and poorly addressed in many segments of the population, novel pharmacological roles for high-dose, intravenous vitamin C in many disease states have now been postulated and investigated. This has shifted its role in health and disease from the long-perceived notion as merely a vitamin and an anti-oxidant to a pleiotropic molecule with a broad anti-inflammatory, epigenetic, and anti-cancer profile.
This Special Issue comprises original research papers and reviews on vitamin C metabolism and function that relate to the following topics: understanding its role in the modulation of inflammation and immunity, therapeutic applications and safety of pharmacological ascorbate in disease, and the emerging role of vitamin C as a pleiotropic modulator of critical care illness and cancer.
The current study focused on the design of an extremely sensitive electrochemical sensor of ascorbic acid based on a mixture of NiAlsub.2Osub.4-NiO nanoparticles that, produced in a single step using ...the sol–gel method, on an ITO electrode. This new sensing platform is useful for the detection of ascorbic acid with a wide range of concentrations extending from the attomolar to the molar. SEM micrographs show the porous structure of the NiAlsub.2Osub.4-NiO sample, with a high specific surface area, which is beneficial for the catalytic performance of the nanocomposite. An XRD diffractogram confirmed the existence of two phases, NiAlsub.2Osub.4 and NiO, both corresponding to the face-centred cubic crystal structure. The performances of the modified electrode, as a biomolecule, in the detection of ascorbic acid was evaluated electrochemically by cyclic voltammetry and chronoamperometry. The sensor exhibited a sensitive electrocatalytic response at a working potential of E = +0.3 V vs. Ag/Ag Cl, reaching a steady-state current within 30 s after each addition of ascorbic acid solution with a wide dynamic range of concentrations extending from attolevels (10sup.−18 M) to molar (10 mM) and limits of detection and quantification of 1.2 × 10sup.−18 M and 3.96 × 10sup.−18 M, respectively. This detection device was tested for the quantification of ascorbic acid in a 500 mg vitamin C commercialized tablet that was not pre-treated.
Object: Experimental and clinical observations indicate oxidative stress and depletion of antioxidants as an important pathogenic mechanism in obesity-associated metabolic abnormalities and in the ...development of DM and its complications. This study is aimed to compare serum concentrations of nutrient antioxidant vitamins, viz., vitamin C and E in subjects divided according to BMI and to find association of vitamin C and E levels with MetS if any.
2-O-Alkyl-l-ascorbic acids and 3-O-alkyl-l-ascorbic acids were synthesized, and their degranulation inhibitory activities were evaluated. Among ascorbic acid derivatives with butyl, octyl, dodecyl, ...hexadecyl, and octadecyl groups introduced at the C-2 or C-3 positions, an AA derivative with a dodecyl group introduced at the C-3 position, 3-O-dodecyl-l-ascorbic acid (compound 8), showed the strongest inhibitory activity against antigen-stimulated degranulation. Compound 8 also inhibited calcium ionophore-stimulated degranulation. Compound 11, in which the hydroxyl group at the C-6 position of compound 8 was substituted with an amino group, and compound 12, in which the dodecyloxy group at the C-3 position of compound 8 was exchanged with a dodecylamino group, were synthesized, and these derivatives showed weaker inhibitory activity against antigen-stimulated degranulation than that of compound 8. In addition, orally administered compound 8 inhibited passive cutaneous anaphylaxis reactions in mice with a potency equal to that of oxatomide, an antiallergic agent. These results suggest that compound 8 may be a candidate for antiallergic treatment.
The global coronavirus pandemic has highlighted the paramount importance of immune health and the nutrient status of peoples worldwide. Vitamins C and D have important roles in both the innate and ...adaptive immune systems and are known to support healthy immune function. Both vitamins C and D have gene regulatory roles with the ability to up- and down-regulate thousands of genes, thus playing pleotropic roles in human health and disease. People from low- and middle-income countries tend to have inadequate micronutrient intakes and status, as do specific subgroups from high-income countries. This can affect their resistance to both communicable and non-communicable diseases and the severity of these diseases. In this Special Issue, we have compiled review articles and research papers (both observational and interventional studies) that explore the role of vitamins C and D in numerous aspects of global and population health.
Helicobacter pylori colonizes human gastric mucosa, overcoming stressful conditions and entering in a dormant state. This study evaluated: (i) H. pylori's physiological changes from active to ...viable-but-non-culturable (VBNC) and persister (AP) states, establishing times/conditions; (ii) the ability of vitamin C to interfere with dormancy generation/resuscitation. A dormant state was induced in clinical MDR H. pylori 10A/13 by: nutrient starvation (for VBNC generation), incubating in an unenriched medium (Brucella broth) or saline solution (SS), and (for AP generation) treatment with 10xMIC amoxicillin (AMX). The samples were monitored after 24, 48, and 72 h, 8-14 days by ODsub.600, CFUs/mL, Live/Dead staining, and an MTT viability test. Afterwards, vitamin C was added to the H. pylori suspension before/after the generation of dormant states, and monitoring took place at 24, 48, and 72 h. The VBNC state was generated after 8 days in SS, and the AP state in AMX for 48 h. Vitamin C reduced its entry into a VBNC state. In AP cells, Vitamin C delayed entry, decreasing viable coccal cells and increasing bacillary/U-shaped bacteria. Vitamin C increased resuscitation (60%) in the VBNC state and reduced the aggregates of the AP state. Vitamin C reduced the incidence of dormant states, promoting the resuscitation rate. Pretreatment with Vitamin C could favor the selection of microbial vegetative forms that are more susceptible to H. pylori therapeutical schemes.
•ASC levels in plant tissue increases at higher irradiance levels due to stimulation of the primary (D-Man/L-Gal) biosynthetic pathway.•The primary biosynthetic pathway accounts for the majority of ...ASC found in plants. Other biosynthetic pathways possibly contribute to the ASC pool only in genetically modified plants.•Respiration, photosynthesis and carbohydrate availability are regulatory cues for ASC in plants.•Respiration and photosynthesis potentially interact in light regulation of ASC via carbohydrates.
l-ascorbate (vitaminC, ASC) is an antioxidant that is essential for the proper function not only of plants but also animals. Light is a major regulatory factor for ASC levels in plants. In this paper, we review the regulation of ASC by light and the involved biochemical and physiological processes. Several biochemical pathways for ASC biosynthesis have been proposed to exist in plants. We aim to determine the contribution of these biochemical pathways on ASC levels and, locate the steps of them that are affected by light. From biochemical and genetic studies only evidence for ASC biosynthesis occurring via the d-mannose/L-galactose biosynthetic pathway was found. Alternative pathways might account for ASC biosynthesis only in transgenic plants. Apart from biosynthesis, recycling and turnover of ASC might affect the size of the ASC pool. Light regulation of ASC levels in plants occurs primarily via effects on biosynthesis. In addition, light affects ASC homeostasis and translocation within the plant. Light regulation of ASC has been studied for individual physiological processes without taking into account possible interactions. By establishing the physiological network behind light regulation of ASC for both leaves and fruit, we developed a novel hypothesis on interactions between the physiological processes that regulate ASC. We conclude that respiration and photosynthesis interact in light regulation of ASC biosynthesis via carbohydrate availability.
Sepsis, a life-threatening organ dysfunction due to a dysregulated host response to infection, is a leading cause of morbidity and mortality worldwide. Decades of research have failed to identify any ...specific therapeutic targets outside of antibiotics, infectious source elimination, and supportive care. More recently, vitamin C has emerged as a potential therapeutic agent to treat sepsis. Vitamin C has been shown to be deficient in septic patients and the administration of high dose intravenous as opposed to oral vitamin C leads to markedly improved and elevated serum levels. Its physiologic role in sepsis includes attenuating oxidative stress and inflammation, improving vasopressor synthesis, enhancing immune cell function, improving endovascular function, and epigenetic immunologic modifications. Multiple clinical trials have demonstrated the safety of vitamin C and two recent studies have shown promising data on mortality improvement. Currently, larger randomized controlled studies are underway to validate these findings. With further study, vitamin C may become standard of care for the treatment of sepsis, but given its safety profile, current treatment can be justified with compassionate use.
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