Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans

Iron modified hydrogen-bonded organic framework as fluorescent sensor for ascorbic acid detection

Herein, iron modified hydrogen-bonded organic framework (Fe-HOF) was successfully prepared by introducing the yellow-green fluorescent ligand 2,5-dihydroxyterephthalic acid into HOF and then modifying Fe3+. A simple turn-on fluorescence strategy is proposed for the detection of ascorbic acid (AA) based on Fe-HOF. Fe3+ could effectively quench fluorescence emission of HOF. In the presence of AA, Fe3+ was reduced to Fe2+, which led to the fluorescence recovery of HOF, thus realizing the fluorescence quantitative detection of AA. These fluorescence responsive behaviors of Fe-HOF ensure fluorescence assay of AA within 0.5 - 8 μM, along with a limit of detection (LOD) of 0.14 μM. The sensing platform could realize the rapid detection of ascorbic acid in vitamin C pills, tablets and beverages in the detection of ascorbic acid with good recoveries.

Anti-allergic effect of vitamin C through inhibiting degranulation and regulating TH1/TH2 cell polarization

BACKGROUND

Food allergy has become a global public health problem. This study aimed to explore the possible anti-allergic effect of vitamin C (VC). A rat basophilic leukemia (RBL)-2H3 cell degranulation model was used to assess the effect of VC on degranulation in vitro, and an ovalbumin (OVA)-induced BALB/c mouse allergy model was used to assess the anti-allergy effect of VC in vivo.

RESULTS

In vitro, VC significantly attenuated the release of β-hexosaminidase, tryptase and histamine, and also reduced cytokine production (interleukins 4 and 6, tumor necrosis factor α) significantly (P < 0.05), with the inhibitory effect demonstrating a positive correlation with VC dose. In vivo, compared with the OVA group, the levels of serum immunoglobulins E and G1 of the VC low-dose (VCL) group (50 mg kg-1) and high-dose (VCH) group (200 mg·kg-1) were significantly reduced (P < 0.05). Furthermore, the plasma histamine level was also significantly decreased (P < 0.05). Moreover, TH2 cell polarization in mice of the VCL and VCH groups was significantly inhibited (P < 0.05), promoting the TH1/TH2 cell polarization balance. Additionally, VC treatment enhanced the expression of CD80 (P < 0.05) in spleen and small intestine tissues, while significantly inhibiting the expression of CD86 (P < 0.05); notably, high-dose VC treatment was more effective.

CONCLUSION

VC exerted an anti-allergic effect through inhibiting degranulation and regulating TH1/TH2 cell polarization balance. © 2024 Society of Chemical Industry.

Association of dietary vitamin C consumption with severe headache or migraine among adults: a cross-sectional study of NHANES 1999-2004

Background

An antioxidant-rich diet has been shown to protect against migraines in previous research. However, little has been discovered regarding the association between migraines and vitamin C (an essential dietary antioxidant). This study assessed the dietary vitamin C intake among adult migraineurs in the United States to determine if there is a correlation between migraine incidence and vitamin C consumption in adults.

Methods

This cross-sectional research encompassed adults who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2004, providing detailed information on their dietary vitamin C intake as well as their history of severe headaches or migraines. The study used weighted multivariable and logistic regression analyses to find an independent connection between vitamin C consumption and severe headache or migraine. Tests of interactions and subgroup analysis were conducted.

Results

Among the 13,445 individuals in the sample, 20.42% had a severe headache or migraine. In fully adjusted models, dietary vitamin C consumption was substantially linked negatively with severe headache or migraine (odds ratio [OR] = 0.94, 95% confidence interval [CI] = 0.91-0.98, p = 0.0007). Compared to quartile 1, quartile 4 had 22% fewer odds of having a severe headache or migraine (OR = 0.78, 95% CI = 0.69-0.89, p = 0.0002). Subgroup analyses showed a significant difference between vitamin C intake and severe headaches or migraines by gender (p for interaction < 0.01).

Conclusion

Reduced risk of severe headaches or migraines may be associated with increased consumption of vitamin C.

A dual-signal optical sensing platform of CDs-MnO2 NS composites for facile detection of ascorbic acid based on a combination of Tyndall effect scattering and fluorescence

A dual-signal optical sensing platform was successfully developed for the determination of ascorbic acid (AA) based on blue fluorescent carbon dots (CDs) and manganese dioxide nanosheets (MnO2 NSs) with strong Tyndall effect (TE) scattering and fluorescence quenching capabilities. In this nanosystem, CDs-MnO2 NS composites were employed as probes to evaluate the AA concentration. Owing to the strong reduction, the presence of the target AA could reduce the MnO2 NSs to Mn2+ and induce the degradation of the MnO2 NSs, resulting in a significant decrease in the TE scattering intensity of the MnO2 NSs and the fluorescence recovery of the CDs. Therefore, a novel optical sensor based on TE scattering and fluorescence dual detectors was developed for the sensitive determination of AA. Under optimized conditions, the limits of detection (LODs) of the two modes were 113 and 3 nM, respectively. Furthermore, the dual-signal optical sensing platform was successfully applied for the detection of AA in human serum.

Combined transcriptomics and proteomics unveil the impact of vitamin C in modulating specific protein abundance in the mouse liver

BACKGROUND

Vitamin C (ascorbate) is a water-soluble antioxidant and an important cofactor for various biosynthetic and regulatory enzymes. Mice can synthesize vitamin C thanks to the key enzyme gulonolactone oxidase (Gulo) unlike humans. In the current investigation, we used Gulo-/- mice, which cannot synthesize their own ascorbate to determine the impact of this vitamin on both the transcriptomics and proteomics profiles in the whole liver. The study included Gulo-/- mouse groups treated with either sub-optimal or optimal ascorbate concentrations in drinking water. Liver tissues of females and males were collected at the age of four months and divided for transcriptomics and proteomics analysis. Immunoblotting, quantitative RT-PCR, and polysome profiling experiments were also conducted to complement our combined omics studies.

RESULTS

Principal component analyses revealed distinctive differences in the mRNA and protein profiles as a function of sex between all the mouse cohorts. Despite such sexual dimorphism, Spearman analyses of transcriptomics data from females and males revealed correlations of hepatic ascorbate levels with transcripts encoding a wide array of biological processes involved in glucose and lipid metabolisms as well as in the acute-phase immune response. Moreover, integration of the proteomics data showed that ascorbate modulates the abundance of various enzymes involved in lipid, xenobiotic, organic acid, acetyl-CoA, and steroid metabolism mainly at the transcriptional level, especially in females. However, several proteins of the mitochondrial complex III significantly correlated with ascorbate concentrations in both males and females unlike their corresponding transcripts. Finally, poly(ribo)some profiling did not reveal significant enrichment difference for these mitochondrial complex III mRNAs between Gulo-/- mice treated with sub-optimal and optimal ascorbate levels.

CONCLUSIONS

Thus, the abundance of several subunits of the mitochondrial complex III are regulated by ascorbate at the post-transcriptional levels. Our extensive omics analyses provide a novel resource of altered gene expression patterns at the transcriptional and post-transcriptional levels under ascorbate deficiency.

Development of a New Extraction Method for Pomegranate and Metabolite Profiling by a LC-MS and 1H NMR Combined Approach

The pomegranate (Punica granatum L.) market has steadily grown due to the increasing demand of health-conscious consumers of products with health-promoting effects. Recently, a growing interest in developing ecological and environmentally friendly extraction methods has led to investigating extraction procedures to obtain a higher extraction yield using a lower amount of solvents and energy. Herein, a new extraction procedure was developed to obtain an enriched pomegranate food supplement by using the peels of pomegranate, cultivar "Dente di Cavallo" and its juice. The extraction was performed through a non-conventional extraction technique like SLDE-Naviglio using ethanol and pomegranate juice as a solvent, and peels as a matrix. The extract was analysed by a combined approach based on LCESI/QExactive/MS/MS and NMR analysis, and its chemical profile was compared with those of pomegranate juice and of the extract obtained from peels by SLDE-Naviglio by using ethanol:H2O. The LC-MS analysis highlighted the presence of hydrolysable tannins, flavonoids, ellagic acid and phenol glucoside derivatives, while 1H NMR analysis completed the profile by detecting the primary metabolites. The LC-MS and 1H NMR analysis indicated that the extract obtained by SLDE-Naviglio using ethanol and pomegranate juice was enriched in the bioactives as confirmed by the highest phenolic, tannin and flavonoid content.

Combining fluorescent quantum dots with transition metal oxide shell as core-shell nanocomposite for turn-on sensing of ascorbic acid

Ascorbic acid (AA) is an essential vitamin in humans, and numerous AA detection studies have been conducted. Most quantum dots (QDs)-based approaches depend on redox reactions involving AA, and they require the introduction of an intermediate (e.g., metal ions, OPD, TMB) or the assembly of fluorescent substances with nanosheets (such as MnO2) that can be degraded by AA. These methods are complex, unstable, and are susceptible to interferences. To address these problems, a core-shell fluorescence probe was developed for turn-on sensing of AA. The transition metal oxide shell FeOOH was generated around the surface of CuInZnS QDs to quench the fluorescence. In the presence of AA, the FeOOH shell was decomposed into Fe2+ and the fluorescence of QDs was recovered. Using a physical shell, the obtained nanocomposite realized direct AA detection, avoiding the effects of interfering substances caused by QDs exposure. Moreover, our probe showed great potential in point-of-care tests and was readily adapted for use as a smartphone-assisted paper sensor.

A High Vitamin C Micronutrient Supplement Is Unable to Attenuate Inflammation in People with Metabolic Syndrome but May Improve Metabolic Health Indices: A Randomised Controlled Trial

Chronic low-grade inflammation is a characteristic of people with metabolic syndrome and is thought to contribute to the condition progressing to the more severe type 2 diabetes and cardiovascular disease (CVD). The aim was to carry out a double-blind randomised placebo-controlled trial in people with metabolic syndrome to determine if supplementation with a micronutrient formula containing 1000 mg/d vitamin C could attenuate inflammation in people with metabolic syndrome. We recruited 72 adults aged a median of 52 years with metabolic syndrome, defined as obesity (based on waist circumference or BMI), and at least two of hyperglycaemia, raised triglycerides, lowered HDL cholesterol, hypertension, or taking medications for these conditions. A further inclusion criteria comprised C-reactive protein (CRP) concentrations ≥ 3 mg/L, i.e., high risk of CVD. The participants were randomised to daily micronutrient formula (n = 37) or matched placebo control (n = 35) for 12 weeks. The primary outcome was change in CRP concentrations and secondary outcomes included changes in vitamin C concentrations, pro-inflammatory cytokines (IL-6, TNFα), oxidative stress marker (F2isoprostanes), glycaemic indices (glucose, insulin, HbA1c), lipid markers (triglycerides, LDL and HDL cholesterol), anthropometric parameters (weight, BMI), insulin resistance and insulin sensitivity, and metabolic severity score. The participants had a low median (Q1, Q3) vitamin C status of 29 (15, 41) µmol/L and a high proportion of hypovitaminosis C (38%) and outright deficiency (19%). Following 12 weeks of micronutrient supplementation, at least 70% of the participants reached adequate vitamin C status (≥50 µmol/L), however, there was no change in CRP concentrations relative to the placebo group (Δ-0.3 [95%CI -2.7, 2.1] mg/L, p = 0.8). Similar trends were observed for IL-6, TNFα and F2isoprostanes (p > 0.05). Instead, there were small improvements in BMI, fasting glucose and HbA1c concentrations, insulin sensitivity and metabolic severity score in the micronutrient group relative to placebo (p < 0.05). Overall, 12-week micronutrient supplementation was unable to mitigate systemic inflammation in people with metabolic syndrome but may improve several metabolic health indices.

Impact of drought stress on vitamin C and anthocyanin content in cultivated lettuces (Lactuca sativa L.) and wild relatives (Lactuca spp.)

Introduction

Lettuce production and quality could be seriously affected by the increasingly limited water resources.

Methods

The effect of drought on the content of two antioxidant compounds, vitamin C and anthocyanins, in five cultivated lettuces and two wild relatives was assessed for 2 years.

Results and discusion

In leaf samples, Lactuca wild species generally had a higher content of total vitamin C than the cultivated lettuces. In contrast, the commercial varieties usually contained more total anthocyanins than the wild species. Total vitamin C decreased with the drought stress in all accessions, commercial varieties, and lettuce wild relatives, with this tendency being consistent and reproducible across the 2 years. These differences were significant in the case of the green commercial varieties 'Winter Crop' (in 2020/2021) and 'Dolomiti G12' (in 2021/2022) and very significant in the red commercial variety 'Red Sails' (in 2020/2021). However, the only group in which the effect of drought was either significant or very significant in both years was the wild species, Lactuca homblei and Lactuca dregeana, and in the latter also in both tissues (leaf and stem) analyzed. Water stress resulted in an increase of the total anthocyanin content in the leaves from all the accessions, both red commercial varieties and wild relatives, in both years. The most significant enrichment and the only one being either significant or very significant in both years was observed in one of the wild relatives assayed (L. homblei). Stems (L. dregeana) contained more anthocyanins than leaves under control conditions, and it was exactly the opposite under drought. Changes in anthocyanins in the two tissues in response to drought stress were in opposite directions, increasing in leaves and decreasing in stems. This could suggest a translocation of anthocyanins as a first quick mechanism to cope with a severe lack of water. In conclusion, anthocyanins (unlike vitamin C) could play a role in the mechanisms deployed by the plant to tolerate drought stress. The wild species with a robust significant enrichment in anthocyanins as a response to drought (L. homblei) is a promising plant material to breed more resilient lettuces.

Strategies for the biological synthesis of D-glucuronic acid and its derivatives

D-glucuronic acid is a kind of glucose derivative, which has excellent properties such as anti-oxidation, treatment of liver disease and hyperlipidemia, and has been widely used in medicine, cosmetics, food and other fields. The traditional production methods of D-glucuronic acid mainly include natural extraction and chemical synthesis, which can no longer meet the growing market demand. The production of D-glucuronic acid by biocatalysis has become a promising alternative method because of its high efficiency and environmental friendliness. This review describes different production methods of D-glucuronic acid, including single enzyme catalysis, multi-enzyme cascade, whole cell catalysis and co-culture, as well as the intervention of some special catalysts. In addition, some feasible enzyme engineering strategies are provided, including the application of enzyme immobilized scaffold, enzyme mutation and high-throughput screening, which provide good ideas for the research of D-glucuronic acid biocatalysis.

Antiaging Strategies and Remedies: A Landscape of Research Progress and Promise

Aging is typified by a gradual loss of physiological fitness and accumulation of cellular damage, leading to deteriorated functions and enhanced vulnerability to diseases. Antiaging research has a long history throughout civilization, with many efforts put forth to understand and prevent the effects of aging. Multiple strategies aiming to promote healthy aging and extend the lifespan have been developed including lifestyle adjustments, medical treatments, and social programs. A multitude of antiaging medicines and remedies have also been explored. Here, we use data from the CAS Content Collection to analyze the publication landscape of recent research related to antiaging strategies and treatments. We review the recent advances and delineate trends in research headway of antiaging knowledge and practice across time, geography, and development pipelines. We further assess the state-of-the-art antiaging approaches and explore their correlations with age-related diseases. The landscape of antiaging drugs has been outlined and explored. Well-recognized and novel, currently evaluated antiaging agents have also been summarized. Finally, we review clinical applications of antiaging products with their development pipelines. The objective of this review is to summarize current knowledge on preventive strategies and treatment remedies in the field of aging, to outline challenges and evaluate growth opportunities, in order to further efforts to solve the problems that remain.

Severe Acute Malnutrition Presenting With Scurvy: A Case Report

Scurvy is a disease caused by a lack of vitamin C. It is a nutritional deficiency that is associated with multiple severe conditions. Although developed countries report these cases rarely now due to advancements in food and nutritional supplements, they are still prevalent in developing countries, albeit rare, because of poor nutritional status. Due to the lower prevalence of scurvy, diagnosis is delayed in the majority of cases and sometimes missed completely, which results in serious complications and unnecessary workups. Here, we present a rare case of a four-year-old female child with severe acute malnutrition (SAM) presenting with scurvy. The initial clinical signs showed SAM. X-ray and MRI of the left femur and knee were done to further evaluate the orthopedic parameters. Clinical presentation and radiographic imaging confirmed all the signs of scurvy. The patient was started on the Formula 75 (F-75) diet to address the severe malnutrition, and steady weight gain was observed.

Mitigating reactive oxygen species production and increasing gel porosity improves lymphocyte motility and fibroblast spreading in photocrosslinked gelatin-thiol hydrogels

On-chip 3D culture systems that incorporate immune cells such as lymphocytes and stromal cells are needed to model immune organs in engineered systems such as organs-on-chip. Photocrosslinking is a useful tool for creating such immune-competent hydrogel cultures with spatial cell organization. However, loss of viability and motility in photocrosslinked gels can limit its utility, especially when working with fragile primary cells. We hypothesized that optimizing photoexposure-induced ROS production, hydrogel porosity or a combination of both factors was necessary to sustain cell viability and motility during culture in photocrosslinked gelatin-thiol (GelSH) hydrogels. Jurkat T cells, primary human CD4+ T cells and human lymphatic fibroblasts were selected as representative lymphoid immune cells to test this hypothesis. Direct exposure of these cells to 385 nm light and LAP photoinitiator dramatically increased ROS levels. Pretreatment with an antioxidant, ascorbic acid (AA), protected the cells from light + LAP-induced ROS and was non-toxic at optimized doses. Furthermore, scanning electron microscopy showed that native GelSH hydrogels had limited porosity, and that adding collagen to GelSH precursor before crosslinking markedly increased gel porosity. Next, we tested the impact of AA pretreatment and increasing gel porosity, alone or in combination, on cell viability and function in 3D GelSH hydrogel cultures. Increasing gel porosity, rather than AA pretreatment, was more critical for rescuing viability of Jurkat T cells and spreading of human lymphatic fibroblasts in GelSH-based gels, but both factors improved the motility of primary human CD4+ T cells. Increased porosity enabled formation of spatially organized co-cultures of primary human CD4+ T cells and human lymphatic fibroblasts in photo-crosslinked gels in a multi-lane microfluidic chip, towards modeling the lymphoid organ microenvironment. Some optimization is still needed to improve homogeneity between regions on the chip. These findings will enable researchers utilizing photocrosslinking methods to develop immunocompetent 3D culture models that support viability and function of sensitive lymphoid cells.

Vitamin C - a scoping review for Nordic Nutrition Recommendations 2023

Vitamin C has multiple metabolic functions in the body, but the available information on the exact relationship between these functions and the intake necessary to maintain them is very limited. However, most attempts to objectively measure adequacy of vitamin C status, including, for example, replacement of metabolic turnover, chronic disease prevention, urinary excretion, and saturation of immune cells and body compartment, currently point toward 50 µmol/L as a reasonable target plasma concentration. As a strong correlation between body weight and vitamin C status exists, recommended intakes (RIs) for other age groups may be extrapolated from the adult RI based on weight. However, as body weights above 70 kg are becoming increasingly common - also in the Nordic region - an RI of 140 mg/day for individuals weighing 100 kg or more should be considered to compensate for the larger volume of distribution. Finally, smoking continues to be a common contributor to poor vitamin C status; therefore, it is proposed that people who smoke increase their daily vitamin C intake by 40 mg/day to compensate for the increased metabolic turnover induced by smoking.

Association of Dietary Vitamin C Consumption with Serum Klotho Concentrations

BACKGROUND

Klotho is widely recognized as a protein that combats aging and possesses antioxidative characteristics, which have been implicated in the pathophysiology of numerous diseases. There is emerging evidence suggesting that the consumption of dietary nutrients, particularly those rich in antioxidants, could be associated with serum Klotho concentrations. Dietary vitamin C is one of the critical nutrients that possesses antioxidant properties. Nonetheless, the association between dietary vitamin C consumption and serum Klotho concentrations remains unclear.

OBJECTIVE

Aiming to evaluate the relationship between serum Klotho concentrations and dietary vitamin C consumption among Americans aged 40 to 79, we conducted a population-based study.

METHODS

From the National Health and Nutrition Examination Survey (NHANES) conducted between 2007 and 2016, a grand total of 11,282 individuals who met the criteria were selected as eligible participants for the study. Serum Klotho concentrations were measured using an ELISA kit that is commercially available. Trained interviewers evaluated the consumption of dietary vitamin C in the diet through a 24-hour dietary recall technique. A generalized linear model was used to evaluate the correlation between the consumption of dietary vitamin C in the diet and serum Klotho concentrations. Further examination was conducted using restricted cubic spline (RCS) analysis to explore the non-linear correlation between dietary vitamin C consumption in the diet and serum Klotho concentrations.

RESULTS

After accounting for possible confounding factors, serum Klotho concentrations rose by 1.17% (95% confidence interval (CI): 0.37%, 1.99%) with every standard deviation (SD) rise in dietary vitamin C consumption. With the first quintile of dietary vitamin C consumption as a reference, the percentage change of serum Klotho concentrations in the fifth quintile of dietary vitamin C consumption was 3.66% higher (95% CI: 1.05%, 6.32%). In older, normal-weight, and male participants, the subgroup analysis revealed a stronger correlation between dietary vitamin C consumption and serum Klotho concentrations. Analysis of RCS showed a linear positive association between dietary vitamin C consumption and the levels of serum Klotho concentrations.

CONCLUSION

The findings of this research indicate a strong and positive correlation between dietary vitamin C consumption and serum Klotho concentrations among the general adult population in the United States. Further studies are needed to validate the present findings and to explore specific mechanisms.

Effectiveness of orange almond potato cookie vs. orange potato cookie supplementation on nutritional wellbeing of the Indonesian stunted preschool-aged children during COVID-19 pandemic

Background

Preschool-aged children who experience stunting due to insufficient consumption of macro- and micronutrients exhibit weakened immune systems, rendering them susceptible to contracting COVID-19 during the ongoing epidemic. Therefore, it is imperative to implement interventions aimed at enhancing the nutritional status of preschool-aged children by providing them with nutrient-rich food supplements as a preventive measure against illness transmission. The objective of the study was to evaluate the impact of incorporating potato almond orange cookies into the diet on the nutritional status of preschool-aged children who are experiencing stunting.

Methods

A non-randomized pre-post intervention study was done on 42 individuals aged 12-58 months during 4 weeks. The intervention group was provided with almond potato cookies, while the control group was given orange potato cookies. During the study period, educational sessions on balanced nutrition in preschool-aged children with stunting and COVID-19 were provided to the mothers of both groups. The data analysis involved conducting univariate and bivariate analyses, namely utilizing the independent t-test.

Results

The intervention group exhibited the most significant enhancements in -for-Age Z-score. The mean -for-Age Z-score of the intervention group increased by 0.51 (from -3.15 to -2.64), whereas the control group saw a smaller gain of 0.25 (from -2.69 to -2.44). This increase was influenced by the mother's age; mother's education; father's occupation; family size; good sanitation facilities; healthy home environment; and fat, calcium, and zinc intake from the cookies (p < 0.05). From the perspective of knowledge about balanced nutrition and COVID-19, there was no significant difference in the -for-Age Z-score in the intervention group.

Conclusion

The ingestion of orange almond potato cookies has the potential to enhance the nutritional wellbeing of children in the preschool age group who are experiencing stunted growth.

Effects of Low Vitamin C Intake on Fertility Parameters and Pregnancy Outcomes in Guinea Pigs

Identifying how specific nutrients can impact fertility, pregnancy, and neonatal outcomes will yield important insights into the biological mechanisms linking diet and reproductive health. Our study investigates how dietary vitamin C intake affects various fertility parameters and pregnancy and neonatal outcomes in the guinea pig, a natural model of vitamin C dependency. Dunkin Hartley guinea pigs were fed an optimal (900 mg/kg feed) or low (100 mg/kg feed) vitamin C diet ad libitum for at least three weeks prior to mating and throughout pregnancy. We found that animals receiving the low vitamin C diet had an increased number of unsuccessful matings, a higher incidence of foetal reabsorption, and, among pregnancies resulting in delivery at term, produced fewer offspring. Neonates from mothers on the low vitamin C diet had significantly decreased plasma vitamin C concentrations at birth and exhibited mild growth impairments in a sex-dependent manner. We conclude that a diet low of vitamin C induces a state of subfertility, reduces overall fecundity, and adversely impacts both pregnancy outcomes and growth in the offspring. Our study provides an essential foundation for future investigations to determine whether these findings translate to humans. If so, they could have important clinical implications for assisted reproductive technologies and nutritional recommendations for couples trying to conceive, pregnant women, and breastfeeding mothers.

Vitamin C fortification: need and recent trends in encapsulation technologies

The multifaceted role of vitamin C in human health intrudes several biochemical functions that are but not limited to antioxidant activity, homoeostasis, amino acid synthesis, collagen synthesis, osteogenesis, neurotransmitter production and several yet to be explored functions. In absence of an innate biosynthetic pathway, humans are obligated to attain vitamin C from dietary sources to maintain its optimal serum level (28 μmol/L). However, a significant amount of naturally occurring vitamin C may deteriorate due to food processing, storage and distribution before reaching to the human gastrointestinal tract, thus limiting or mitigating its disease combating activity. Literature acknowledges the growing prevalence of vitamin C deficiency across the globe irrespective of geographic, economic and population variations. Several tools have been tested to address vitamin C deficiency, which are primarily diet diversification, biofortification, supplementation and food fortification. These strategies inherit their own advantages and limitations. Opportunely, nanotechnology promises an array of delivery systems providing encapsulation, protection and delivery of susceptible compounds against environmental factors. Lack of clear understanding of the suitability of the delivery system for vitamin C encapsulation and fortification; growing prevalence of its deficiency, it is a need of the hour to develop and design vitamin C fortified food ensuring homogeneous distribution, improved stability and enhanced bioavailability. This article is intended to review the importance of vitamin C in human health, its recommended daily allowance, its dietary sources, factors donating to its stability and degradation. The emphasis also given to review the strategies adopted to address vitamin c deficiency, delivery systems adopted for vitamin C encapsulation and fortification.

Associations of serum vitamin C concentrations with risk of all-cause and cause-specific mortality among individuals with and without type 2 diabetes

PURPOSE

Compared with people without diabetes, people with type 2 diabetes (T2D) are at higher risk of both subnormal vitamin C status and increased oxidative stress. We aimed to investigate the associations of serum vitamin C concentrations with all-cause and cause-specific mortality among adults with and without T2D.

METHODS

The current analysis included 20,045 adults (2691 people with T2D and 17,354 without T2D) from the Third National Health and Nutrition Examination Survey (NHANES III) and NHANES 2003-2006. Cox proportional hazards regression models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Restricted cubic spline analyses were used to examine the dose-response relationship.

RESULTS

After a median follow-up of 17.3 years, 5211 deaths were documented. Individuals with T2D had a lower level of serum vitamin C concentrations compared with those without T2D (the median value: 40.1 vs. 44.9 μmol/L). Furthermore, the dose-response relationship between serum vitamin C and mortality showed different patterns between participants with and without T2D. In individuals without T2D, there was a nonlinear association of serum vitamin C concentrations with all-cause, cancer, and CVD mortality, with the lowest risk around a serum vitamin C concentration of 48.0 μmol/L (all Poverall < 0.05, Pnonlinearity < 0.05). In contrast, among those with T2D in the similar concentration range, higher serum vitamin C levels (ranged from 0.46 to 116.26 μmol/L) were linearly associated with lower all-cause and cancer mortality (both Poverall < 0.05, Pnonlinearity > 0.05). Significant additive interaction was observed between diabetes status and serum vitamin C levels with regard to all-cause and cancer mortality (P < 0.001). In addition, C-reactive protein, gamma-glutamyl transpeptidase, and HbA1c explained 14.08, 8.96, and 5.60% of the association between serum vitamin C and all-cause mortality among individuals with T2D, respectively.

CONCLUSIONS

Higher serum vitamin C concentrations were significantly associated with lower risk of mortality in participants with T2D in a linear dose-response manner, while a nonlinear association was observed in participants without T2D, with an apparent threshold around 48.0 μmol/L. These findings suggest that the optimal vitamin C requirement may differ in individuals with and without T2D.

Adjunctive intravenous then oral vitamin C for moderate and severe community-acquired pneumonia in hospitalized adults: feasibility of randomized controlled trial

Patients hospitalised with community acquired pneumonia (CAP) have low peripheral blood vitamin C concentrations and limited antioxidant capacity. The feasibility of a trial of vitamin C supplementation to improve patient outcomes was assessed. Participants with moderate and severe CAP (CURB-65 ≥ 2) on intravenous antimicrobial treatment were randomised to either intravenous vitamin C (2.5 g 8 hourly) or placebo before switching to oral intervention (1 g tds) for 7 days when they were prescribed oral antimicrobial therapy. Of 344 patients screened 75 (22%) were randomised and analysed. The median age was 76 years, and 43 (57%) were male. In each group, one serious adverse event that was potentially intervention related occurred, and one subject discontinued treatment. Vitamin C concentrations were 226 µmol/L in the vitamin C group and 19 µmol/L in the placebo group (p < 0.001) after 3 intravneous doses. There were no signficant differences between the vitamin C and placebo groups for death within 28 days (0 vs. 2; p = 0.49), median length of stay (69 vs. 121 h; p = 0.07), time to clinical stability (22 vs. 49 h; p = 0.08), or readmission within 30 days (1 vs. 4; p = 0.22). The vitamin C doses given were safe, well tolerated and saturating. A randomised controlled trial to assess the efficacy of vitamin C in patients with CAP would require 932 participants (CURB-65 ≥ 2) to observe a difference in mortality and 200 participants to observe a difference with a composite endpoint such as mortality plus discharge after 7 days in hospital. These studies are feasible in a multicentre setting.

TFOS Lifestyle: Impact of nutrition on the ocular surface

Nutrients, required by human bodies to perform life-sustaining functions, are obtained from the diet. They are broadly classified into macronutrients (carbohydrates, lipids, and proteins), micronutrients (vitamins and minerals) and water. All nutrients serve as a source of energy, provide structural support to the body and/or regulate the chemical processes of the body. Food and drinks also consist of non-nutrients that may be beneficial (e.g., antioxidants) or harmful (e.g., dyes or preservatives added to processed foods) to the body and the ocular surface. There is also a complex interplay between systemic disorders and an individual's nutritional status. Changes in the gut microbiome may lead to alterations at the ocular surface. Poor nutrition may exacerbate select systemic conditions. Similarly, certain systemic conditions may affect the uptake, processing and distribution of nutrients by the body. These disorders may lead to deficiencies in micro- and macro-nutrients that are important in maintaining ocular surface health. Medications used to treat these conditions may also cause ocular surface changes. The prevalence of nutrition-related chronic diseases is climbing worldwide. This report sought to review the evidence supporting the impact of nutrition on the ocular surface, either directly or as a consequence of the chronic diseases that result. To address a key question, a systematic review investigated the effects of intentional food restriction on ocular surface health; of the 25 included studies, most investigated Ramadan fasting (56%), followed by bariatric surgery (16%), anorexia nervosa (16%), but none were judged to be of high quality, with no randomized-controlled trials.

Redox Signaling Modulates Activity of Immune Checkpoint Inhibitors in Cancer Patients

Although immunotherapy is already a staple of cancer care, many patients may not benefit from these cutting-edge treatments. A crucial field of research now focuses on figuring out how to improve treatment efficacy and assess the resistance mechanisms underlying this uneven response. For a good response, immune-based treatments, in particular immune checkpoint inhibitors, rely on a strong infiltration of T cells into the tumour microenvironment. The severe metabolic environment that immune cells must endure can drastically reduce effector activity. These immune dysregulation-related tumour-mediated perturbations include oxidative stress, which can encourage lipid peroxidation, ER stress, and T regulatory cells dysfunction. In this review, we have made an effort to characterize the status of immunological checkpoints, the degree of oxidative stress, and the part that latter plays in determining the therapeutic impact of immunological check point inhibitors in different neoplastic diseases. In the second section of the review, we will make an effort to assess new therapeutic possibilities that, by affecting redox signalling, may modify the effectiveness of immunological treatment.

A novel TMD-based peroxidase-mimicking nanozyme: From naked eye detection of leukocytosis-related diseases to sensing different bioanalytes

Being emerged as alternatives to natural enzymes, nanozymes have recently drawn much attention in sensing. Herein, the first multicomponent transition metal dicalchogenide (TMD)-based nanozyme (MCFS/rGO) was synthesized by a facile hydrothermal method and characterized. This peroxidase-mimic nanozyme follows the typical Michaelis-Menten kinetics, showing a higher affinity for H₂O₂ substrate (K_m = 9 μM) compared to that of natural peroxidase (K_m = 3700 μM). The remarkable potential of the MCFS/rGO nanozyme to detect H₂O₂ provided us with a great opportunity to design some simple and fast colorimetric sensing systems. Coupling the efficient peroxidase-mimicking activity of the nanozyme with the H₂O₂ production capacity of white blood cells (WBCs) leads to the development of a novel, simple, rapid, and efficient colorimetric method to distinguish leukocytosis-related patients from healthy people by the naked eye. This pioneering diagnostic technique can also be utilized to quantitatively measure the WBC count. Moreover, we coupled the mentioned nanozyme-based system with the activity of glucose oxidase enzyme available in different types of honey samples, an innovative mechanism proved to be an effective quality indicator of the samples. Last but not least, the MCFS/rGO nanozyme is also able to determine the quantity of some biologically significant analytes, including glutathione (GSH), ascorbic acid (AA), and mercury ions (Hg²⁺), of which the limit of detection (LOD) was 9.3 nM, 22.5 nM, and 0.32 μM, respectively. Our results, however, demonstrated the superior performance of the MCFS/rGO nanozyme to determine the first two mentioned bioanalytes compared with other TMDs. Overall, this novel nanozyme-based sensor system can be considered a suitable candidate for developing multipurpose biosensors for medical and biochemical applications.

The effects of vitamin C on respiratory, allergic and immunological diseases: an experimental and clinical-based review

Vitamin C is used in modern medicine supplements for treatment of various disorders associated with oxidative stress, inflammation and immune dysregulation. In this review article, experimental and clinical results regarding the effects of vitamin C on respiratory immunologic, and allergic diseases are reviewed. Various databases and appropriate keywords are used to search the effect of vitamin C on respiratory diseases until the end of May 2022. Books, theses and articles were included. These studies assessed the effects of vitamin C on respiratory disorders including asthma, chronic obstructive pulmonary disease (COPD), lung infection and lung cancer. Vitamin C showed relaxant effect on tracheal smooth muscle via various mechanisms. The preventive effects of vitamin C were mediated by antioxidant, immunomodulatory and anti-inflammatory mechanisms in the experimental animal models of different respiratory diseases. Some clinical studies also indicated the effect of vitamin C on lung cancer and lung infections. Therefore, vitamin C could be used a preventive and/or relieving therapy in respiratory diseases.

Is vitamin C a booster of the effects of dietary nitrate on endothelial function? Physiologic rationale and implications for research

Endothelial dysfunction (ED) is an early marker of vascular damage linked to the loss of integrity of the endothelial lining and represents a key step in the pathogenesis of atherosclerosis and cardiovascular diseases (CVDs). ED may be reversible, hence the development and testing of effective early interventions could be beneficial for the prevention and treatment of CVDs. Recent studies have demonstrated that the consumption of dietary nitrate (NO₃^-), an inorganic anion that serves as a substrate for the gas transmitter nitric oxide (NO), can lower blood pressure, improve endothelial function and, in observational studies, reduce the risk for CVD. We hypothesize that the co-consumption of NO₃^- with vitamin C, which is a potent antioxidant, could enhance the "yield" of NO produced from a given NO₃^- dose byThis could translate into greater NO-dependent effects on endothelial function (EF) and overall vascular health (than may be experienced with NO₃^- supplementation alone). This review presents evidence to suggest that the combination of vitamin C and dietary nitrate could represent a promising and effective approach to improve EF and reduce CVD risk, and discuss opportunities for future research.

Salmonella Typhimurium Infection Reduces the Ascorbic Acid Uptake in the Intestine

Salmonella Typhimurium infection of the gastrointestinal tract leads to damage that compromises the integrity of the intestinal epithelium and results in enterocolitis and inflammation. Salmonella infection promotes the expression of inflammasome NLRP3, leading to activation and release of proinflammatory cytokines such as IL-1β, and the infected host often displays altered nutrient levels. To date, the effect of Salmonella infection and proinflammatory cytokine IL-1β on the intestinal uptake of ascorbic acid (AA) is unknown. Our results revealed a marked decrease in the rate of AA uptake in mouse jejunum infected with Salmonella wild type (WT). However, the nonpathogenic mutant (Δ invA Δ spiB) strain did not affect AA uptake. The decrease in AA uptake due to Salmonella WT infection is accompanied by significantly lower expression of mouse (m)SVCT1 protein, mRNA, and hnRNA levels. NLRP3 and IL-1β expression levels were markedly increased in Salmonella-infected mouse jejunum. IL-1β-exposed Caco-2 cells displayed marked inhibition in AA uptake and significantly decreased hSVCT1 expression at both protein and mRNA levels. Furthermore, the activity of the SLC23A1 promoter was significantly inhibited by IL-1β exposure. In addition, GRHPR (a known SVCT1 interactor) protein and mRNA expression levels were significantly reduced in Salmonella-infected mouse jejunum. These results indicate that Salmonella infection inhibits AA absorption in mouse jejunum and IL-1β-exposed Caco-2 cells. The observed inhibitory effect may partially be mediated through transcriptional mechanisms.

In Vitro Bioaccessibility of Bioactive Compounds of Freeze-Dried Orange Juice Co-Product Formulated with Gum Arabic and Modified Starch

The large amount of waste generated by the orange juice industry has sparked the interest of many researchers in incorporating recycling systems and following a much more sustainable circular economy model. This work proposes the valorization of the co-product generated in the orange juice extraction industry after freeze-drying for its subsequent reuse as a natural ingredient in the food industry. In addition, the possible protective effect of gum Arabic and corn starch esterified with octenyl succinic groups, in proportions optimised in previous studies 0.25 and 0.45 g/g orange co-product dry solutes, on the main bioactive compounds of orange peel during the freeze-drying process has been studied. The samples were characterised for their content of vitamin C (ascorbic and dehydroascorbic acids), flavonoids (hesperidin and narirutin), total phenols and total carotenoids, as well as their antioxidant capacity (DPPH and FRAP assays). In addition, samples were digested, mimicking the human enzymatic oral gastro-intestinal digestion process, and the bioaccessibility of the bioactive compounds was evaluated. It was observed that the addition of both biopolymers improved the stability of the hydrophilic compounds during freeze-drying. This conservative effect was more remarkable for higher biopolymer concentrations. However, no protective effect on carotenoid compounds was observed. This trend was reflected in the antioxidant activity of the different samples. In addition, the incorporation of biopolymers improved the bioaccessibility of the bioactive compounds studied. In conclusion, the results supported the feasibility of the freeze-dried orange juice co-product as a natural, sustainable source of health-promoting compounds.

Gene expression profiling in Rosa roxburghii fruit and overexpressing RrGGP2 in tobacco and tomato indicates the key control point of AsA biosynthesis

Rosa roxburghii Tratt. is an important commercial horticultural crop endemic to China, which is recognized for its extremely high content of L-ascorbic acid (AsA). To understand the mechanisms underlying AsA overproduction in fruit of R. roxburghii, content levels, accumulation rate, and the expression of genes putatively in the biosynthesis of AsA during fruit development have been characterized. The content of AsA increased with fruit weight during development, and AsA accumulation rate was found to be highest between 60 and 90 days after anthesis (DAA), with approximately 60% of the total amount being accumulated during this period. In vitro incubating analysis of 70DAA fruit flesh tissues confirmed that AsA was synthesized mainly via the L-galactose pathway although L-Gulono-1, 4-lactone was also an effective precursor elevating AsA biosynthesis. Furthermore, in transcript level, AsA content was significantly associated with GDP-L-galactose phosphorylase (RrGGP2) gene expression. Virus-induced RrGGP2 silencing reduced the AsA content in R. roxburghii fruit by 28.9%. Overexpressing RrGGP2 increased AsA content by 8-12-fold in tobacco leaves and 2.33-3.11-fold in tomato fruit, respectively, and it showed enhanced resistance to oxidative stress caused by paraquat in transformed tobacco. These results further justified the importance of RrGGP2 as a major control step to AsA biosynthesis in R. roxburghii fruit.

Vitamin C Deficiency Exacerbates Dysfunction of Atherosclerotic Coronary Arteries in Guinea Pigs Fed a High-Fat Diet

Vitamin C (vitC) deficiency has been associated with an increased risk of cardiovascular disease; while several putative mechanistic links have been proposed, functional evidence supporting a causal relationship is scarce. In this study, we investigated how vitC deficiency affects coronary artery vasomotor function and the development of coronary atherosclerotic plaques in guinea pigs subjected to chronic dyslipidemia by a high-fat diet regime. Female Hartley guinea pigs were fed either a control (low-fat diet and sufficient vitC) (N = 8) or a high-fat diet with either sufficient (N = 8) or deficient (N = 10) vitC for 32 weeks. Guinea pigs subjected to the high-fat diet developed significant atherosclerotic plaques in their coronary arteries, with no quantitative effect of vitC deficiency. In isolated coronary arteries, vasomotor responses to potassium, carbachol, nitric oxide, or bradykinin were studied in a wire myograph. Carbachol, bradykinin, and nitric oxide mediated relaxation in the coronary arteries of the control group. While vasorelaxation to carbachol and nitric oxide was preserved in the two high-fat diet groups, bradykinin-induced vasorelaxation was abolished. Interestingly, bradykinin induced a significant contraction in coronary arteries from vitC-deficient guinea pigs (p < 0.05). The bradykinin-induced contraction was unaffected by L-NAME but significantly inhibited by both indomethacin and vitC, suggesting that, during vitC deficiency, increased release of arachidonic acid metabolites and vascular oxidative stress are involved in the constrictor effects mediated by bradykinin. In conclusion, the present study shows supporting evidence that poor vitC status negatively affects coronary artery function.

Metal-organic framework-derived porous ternary ZnCo2O4 nanoplate arrays grown on carbon cloth for simultaneous electrochemical determination of ascorbic acid, dopamine, and uric acid

Metal-organic frameworks derived from ternary metal oxide directly grown on the conductive substrate have attracted great interest in electrochemical sensing. In this work, metal-organic framework-derived ternary ZnCo₂O₄ nanoplate arrays that were grown on carbon cloth (ZnCo₂O₄ NA/CC) are fabricated and applied for the electrochemical determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). Field emission scanning electron microscope (FESEM) reveals that a network-like CC substrate is covered with considerable nanoplate arrays, presenting a large specific area. X-ray photoelectron spectroscopy (XPS) demonstrates the nanoplate arrays to be composed of ZnCo₂O₄. Benefiting from the unique array morphology and ternary element composition, the ZnCo₂O₄ NA/CC shows desirable performances for simultaneous detection of AA, DA, and UA. The individual detection limits are 7.14 μM for AA, 0.25 μM for DA, and 0.33 μM for UA. Additionally, the ZnCo₂O₄ NA/CC is successfully applied for the quantitative determination of AA, DA, and UA in spiked serum samples, showing its great application potential.

Vitamin C modulates the levels of several proteins of the mitochondrial complex III and its activity in the mouse liver

Ascorbate is a crucial antioxidant and essential cofactor of biosynthetic and regulatory enzymes. Unlike humans, mice can synthesize ascorbate thanks to the key enzyme gulonolactone oxidase (Gulo). In the present study, we used the Gulo-/- mouse model, which cannot synthesize their own ascorbate to determine the impact of this vitamin on the liver proteome of specific subcellular organelles. We performed label-free Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) global quantitative proteomic profiling to identify and quantify proteins in microsomal enriched liver extracts (MEE) from Gulo-/- mice treated with 0-0.4% (w/v) ascorbate in drinking water until the age of four months. Using a principal component analysis on normalized and imputed data of the label-free protein quantifications, a sex-based difference in MEE proteome profiles was observed for all the different ascorbate treated mice. Suboptimal hepatic ascorbate concentrations affected the levels of more proteins and hence biochemical processes in females than in males. Nevertheless, Pearson correlation analyses revealed that the MS intensities of various proteins involved in complement activation inversely correlated with liver ascorbate concentrations in both Gulo-/- males and females. Moreover, the correlation analyses also indicated that several proteins in the mitochondrial complex III of the electron transport chain positively correlated with liver ascorbate concentrations in both Gulo-/- females and males. Consequently, the mitochondrial complex III activity in Gulo-/- female and male mice treated with suboptimal hepatic concentrations of ascorbate was significantly lower than Gulo-/- mice treated with optimal ascorbate concentration. Finally, the whole liver of ascorbate-deficient Gulo-/- mice exhibited lower ATP levels and increased reactive oxygen species. These findings provide new information on how ascorbate deficiency potentially induces mitochondrial dysfunction in the liver of mice.

Valproic acid upregulates sodium-dependent vitamin C transporter-2 functional expression in neuronal cells

Neuronal uptake of ascorbic acid (AA) in humans occurs via the human sodium-dependent vitamin C transporter-2 (hSVCT2). Recent studies show that a significantly lower level of vitamin C is present in the blood of epileptic patients. Consequently, focused studies investigating the involved molecular mechanisms for hSVCT2 regulation are vital to enhance vitamin C body homeostasis. Currently, little is known about the role of valproic acid (VPA), a drug utilized to treat epilepsy and a class I histone deacetylase inhibitor (HDACi), on AA uptake in neuronal systems. Thus, this study aims to examine the effect of VPA on hSVCT2 functional expression in neuronal cells. VPA treatment upregulated the AA uptake and this increased AA uptake was associated with a significant increase in hSVCT2 expression and SLC23A2 promoter activity in SH-SY5Y cells. Knockdown of HDAC2, a predominant isoform in neuronal systems, significantly increased hSVCT2 functional expression. VPA treatment in mice displayed increased mouse (m)SVCT2 protein, mRNA and heterogenous nuclear RNA (hnRNA) expression in the brain. In addition, Yin Yang-1 (YY1), a transcription factor that drives the SLC23A2 promoter activity, protein and mRNA expression levels were markedly upregulated in VPA-treated SH-SY5Y cells and mice brain. Together, our findings suggest that VPA upregulates the functional expression of SVCT2 via HDAC2 and transcriptional mechanism(s).

Effectiveness of Dietary Intervention with Iron and Vitamin C Administered Separately in Improving Iron Status in Young Women

In order to maintain an adequate iron status in young women, effective dietary interventions should provide sufficient amounts of iron in everyday meals and improve the bioavailability of non-heme iron by providing vitamin C. While some intervention studies administering products rich in vitamin C in conjunction with iron sources showed improved iron status, it is unknown whether a separate administration of products rich in iron and vitamin C may be a successful strategy as well. The aim of this study was to assess the effectiveness of dietary intervention with iron and vitamin C administered separately in improving iron status in young women to prevent iron deficiency anemia. The study was conducted in a group of 29 women aged 18-30, and an 8-week dietary intervention was performed. Study participants with an adequate iron status received 50 g of iron-fortified oat flakes (as a source of non-heme iron) with breakfast and 200 mL of orange juice (as a source of vitamin C) in the second part of the day. Iron status was analyzed based on red blood cells, hemoglobin, hematocrit, serum ferritin, and serum iron, and it was assessed at baseline, after 4 weeks, and after 8 weeks of the intervention. The intakes of iron, vitamin C, and folate were controlled throughout the study period, and menstrual blood loss was estimated. After 8 weeks of intervention, statistically significant differences compared with baseline were observed only for hematocrit, as its level after 8 weeks of intervention was higher than the baseline (p = 0.0491). Comparing subsamples within the dietary intervention considered effective and ineffective for red blood cell levels, it was indicated that lower baseline vitamin C intake may result in a more effective dietary intervention (p = 0.0231). Comparing subsamples within the dietary intervention considered effective and ineffective for hemoglobin, hematocrit, iron, and serum ferritin levels, it was indicated that higher baseline levels of hemoglobin (p = 0.0143), hematocrit (p = 0.0497), iron (p = 0.0101), and serum ferritin (p = 0.0343) respectively may result in a more effective dietary intervention. It was concluded that dietary intervention with iron and vitamin C administered separately may be effective in improving iron status in young women to prevent iron deficiency anemia. It may be concluded that in the studied group, a better baseline iron status and lower baseline vitamin C intake may result in a more effective dietary intervention with iron and vitamin C administered separately to improve iron status in young women.

2D/3D-Shaped Fe0.8Ni0.2S2/ZIF-67 as a Nanozyme for Rapid Measurement of H2O2 and Ascorbic Acid with a Low Limit of Detection

Metal-organic frameworks (MOFs) can be used as ideal artificial nanozymes for an open structure to transfer substances and products. The nanozymic mechanism of MOFs needs further investigation for wide application. In this manuscript, no peroxidase-like activity was found for ZIF-67 (a kind of MOF), however, it enhanced the peroxidase-like activity of the Fe_0.8Ni_0.2S₂/ZIF-67 composite, in which Fe_0.8Ni_0.2S₂ was the active composition. The catalytic constant (K_cat) is higher at 1.98 (for TMB) and 2.08 (for H₂O₂) times and the catalytic efficiency (K_cat/K_m) is higher at 3.13 (for TMB) and 2.67 (for H₂O₂) times, than those of Fe_0.8Ni_0.2S₂. The K_m value decreased about 85 times (for H₂O₂) for Fe_0.8Ni_0.2S₂/ZIF-67 than that of horseradish peroxidase (natural enzyme). The mechanism was proposed. The limit of detection of H₂O₂ for Fe_0.8Ni_0.2S₂/ZIF-67 is 0.039 μM, which is lower by about 18.2 times than that of Fe_0.8Ni_0.2S₂. Simultaneously, Fe_0.8Ni_0.2S₂/ZIF-67 was used to rapidly detect ascorbic acid for only 1.0 min in food monitoring. This study may be important to design a new kind of nanozyme.

Ultrathin g-C3N4 nanosheet-CoOOH nanocomposite for fluorescence imaging of ascorbic acid in living cells

Ascorbic acid (AA), a critical cellular metabolite involved in many biochemical pathways, is an important antioxidant in human body. Therefore, it is of great significance to monitor AA in living cells. Nowadays, there are various technologies developed for the detection of AA, but few methods could sensitively and selectively detect the intracellular AA. Here, we reported a highly efficient biosensor (g-C₃N₄-CoOOH nanocomposite) based on ultrathin graphitic carbon nitride (g-C₃N₄) nanosheets and CoOOH nanoflakes, for sensitive detection and fluorescence imaging of AA in living cell. The g-C₃N₄ used here as fluorescence donor is a promising bioimaging nanomaterial because of their high fluorescence quantum yield, good biocompatibility and low toxicity. In addition, the CoOOH was used to be perfect fluorescence quencher. Herein, we enabled the CoOOH in situ to form a layer on the surface of g-C₃N₄, resulting in fluorescence quench of the g-C₃N₄. Upon the addition of AA, the CoOOH nanoflakes were reduced to Co²⁺, and the system gave a "turn on" fluorescence signal. It developed as an efficient sensing platform for AA, and the linear range was from 5 to 50 μM with a 1.6 μM detection limit. This novel biosensor, g-C₃N₄-CoOOH nanocomposite exhibited highly selective response toward AA relative to other biomolecules. Furthermore, this biosensor was used successfully to visualize and monitor AA in living cells. Hopefully, we believe that this biosensor would provide a low-cost and highly sensitive platform for AA detection and bioimaging. Schematic illustration of the sensing strategy based on the g-C₃N₄-CoOOH nanocomposite for AA detection.

The Mutual Relationship among Cardiovascular Diseases and COVID-19: Focus on Micronutrients Imbalance

Micronutrients are ions and vitamins humbly required by the human body. They play a main role in several physiological mechanisms and their imbalance is strongly associated with potentially-fatal complications. Micronutrient imbalance is associated with many cardiovascular diseases, such as arrythmias, heart failure, and ischemic heart disease. It has been also observed in coronavirus disease 2019 (COVID-19), particularly in most severe patients. The relationship between cardiovascular diseases and COVID-19 is mutual: the latter triggers cardiovascular disease onset and worsening while patients with previous cardiovascular disease may develop a more severe form of COVID-19. In addition to the well-known pathophysiological mechanisms binding COVID-19 and cardiovascular diseases together, increasing importance is being given to the impact of micronutrient alterations, often present during COVID-19 and able to affect the balance responsible for a good functioning of the cardiovascular system. In particular, hypokalemia, hypomagnesemia, hyponatremia, and hypocalcemia are strongly associated with worse outcome, while vitamin A and D deficiency are associated with thromboembolic events in COVID-19. Thus, considering how frequent the cardiovascular involvement is in patients with COVID-19, and how it majorly affects their prognosis, this manuscript provides a comprehensive review on the role of micronutrient imbalance in the interconnection between COVID-19 and cardiovascular diseases.

Identification of key genes controlling L-ascorbic acid during Jujube (Ziziphus jujuba Mill.) fruit development by integrating transcriptome and metabolome analysis

Chinese jujube (Ziziphus jujuba) is a vital economic tree native to China. Jujube fruit with abundant L-Ascorbic Acid (AsA) is an ideal material for studying the mechanism of AsA biosynthesis and metabolism. However, the key transcription factors regulating AsA anabolism in jujube have not been reported. Here, we used jujube variety "Mazao" as the experimental material, conducted an integrative analysis of transcriptome and metabolome to investigate changes in differential genes and metabolites, and find the key genes regulating AsA during jujube fruit growth. The results showed that AsA was mostly synthesized in the young stage and enlargement stage, ZjMDHAR gene takes an important part in the AsA recycling. Three gene networks/modules were highly correlated with AsA, among them, three genes were identified as candidates controlling AsA, including ZjERF17 (LOC107404975), ZjbZIP9 (LOC107406320), and ZjGBF4 (LOC107421670). These results provide new directions and insights for further study on the regulation mechanism of AsA in jujube.

Pharmacokinetics of a Novel Sustained-Release Vitamin C Oral Tablet: A Single Dose, Randomized, Double-Blind, Placebo-Controlled Trial

Introduction

Vitamin C is available in various oral formulations for dietary supplementation and for use in deficiency. However, because of the saturable active transport mechanisms in the absorption, distribution, and excretion of vitamin C, oral doses above 400 mg/day are not effectively absorbed. This may be overcome by employing slow-release delivery systems. We tested this by evaluating the pharmacokinetics of a novel sustained-release oral tablet (C-Fence, Inventia Healthcare Limited, Mumbai, India).

Methods

We conducted a randomized, placebo-controlled, parallel-design, 500 mg single-dose pharmacokinetic study of this new preparation in 18 healthy, adult, human subjects (nine in each group) under fasting conditions. The concentration-time profile and pharmacokinetic parameters of L-ascorbic acid, including Cmax (maximum plasma concentration), Tmax (time to reach Cmax), and AUC0-24h (area under the plasma concentration versus time curve from time 0 h to 24 h) were calculated using baseline-corrected values.

Results

The sustained-release tablets resulted in mean Cmax and AUC0-24h, respectively, of 1.39 ± 1.21 µg/mL and 11.72 ± 10.73 µg.h/mL against 0.18 ± 0.10 µg/mL and 0.89 ± 0.27 µg.h/mL, respectively, in the placebo group. The mean Tmax with the sustained release tablets was 4.3 ± 2.5 h. At 12, 16, and 24 h from dosing, the concentrations were 0.6, 0.4, and 0.3 µg/mL, respectively, above baseline values.

Conclusion

Novel sustained-release formulations of vitamin C are expected to help achieve plasma vitamin C values above the homeostatic saturation level and result in higher steady-state plasma concentration, which might result in better cellular uptake.

Ascorbate as a Bioactive Compound in Cancer Therapy: The Old Classic Strikes Back

Cancer is a disease of high mortality, and its prevalence has increased steadily in the last few years. However, during the last decade, the development of modern chemotherapy schemes, new radiotherapy techniques, targeted therapies and immunotherapy has brought new hope in the treatment of these diseases. Unfortunately, cancer therapies are also associated with frequent and, sometimes, severe adverse events. Ascorbate (ascorbic acid or vitamin C) is a potent water-soluble antioxidant that is produced in most mammals but is not synthesised endogenously in humans, which lack enzymes for its synthesis. Ascorbate has antioxidant effects that correspond closely to the dose administered. Interestingly, this natural antioxidant induces oxidative stress when given intravenously at a high dose, a paradoxical effect due to its interactions with iron. Importantly, this deleterious property of ascorbate can result in increased cell death. Although, historically, ascorbate has been reported to exhibit anti-tumour properties, this effect has been questioned due to the lack of available mechanistic detail. Recently, new evidence has emerged implicating ferroptosis in several types of oxidative stress-mediated cell death, such as those associated with ischemia–reperfusion. This effect could be positively modulated by the interaction of iron and high ascorbate dosing, particularly in cell systems having a high mitotic index. In addition, it has been reported that ascorbate may behave as an adjuvant of favourable anti-tumour effects in cancer therapies such as radiotherapy, radio-chemotherapy, chemotherapy, immunotherapy, or even in monotherapy, as it facilitates tumour cell death through the generation of reactive oxygen species and ferroptosis. In this review, we provide evidence supporting the view that ascorbate should be revisited to develop novel, safe strategies in the treatment of cancer to achieve their application in human medicine.

Evaluation of functional attributes and storage stability of novel juice blends from baobab, pineapple, and black-plum fruits

Several under-utilized tropical fruits have exceptional micronutrients and phytochemical composition with the potential to contribute to the nutrition of people and also enhance food security. This study was carried out to evaluate the quality attributes and storage stability of juice blends of baobab (Adansonia digitata), pineapple (Ananas comosus), and black-plum (Syzygium cumini) fruits for use as functional beverages. Juice blends were analyzed for physicochemical, antioxidant, and sensory properties. Mineral compositions and storage stability of the pasteurized juice blends at 4 °C for 4 weeks were also investigated. Results showed that the vitamin C contents of individual juices synergistically contributed to the high values observed in the blends (317.45–414.51 mg/L). Juice blends of baobab, pineapple, and black-plum fruits are good sources of calcium (57–153 mg/L), magnesium (71–130 mg/L) and antioxidants (ascorbic acid, total polyphenol contents (65–104 mg GAE/100 mL), scavenging ability (105.97–359.71 μmol TE/100 mL), and reducing potential (1376–1829 μMFe²⁺ L) the consumption of which will promote human health. Blending enhanced the sensory qualities of the individual juices with improved taste and consumer acceptability. The juice blends kept well for two weeks at 4 °C though the color becomes less intense at the end of the storage period. These findings suggest that baobab-fruit pulp, pineapple, and black-plum fruits can be major ingredients in producing a consumer acceptable anti-oxidant rich functional beverage for optimal benefits to consumers.

•

Fruit juice blends were made from pineapples, baobab, and black-plum fruits.

•

The blends are rich sources of essential micronutrients and antioxidants.

•

Blending improved juice antioxidant capacity and consumer acceptability.

•

Blends kept well for two weeks without significant physicochemical changes.

Chemical composition and bioactive compounds of cashew (Anacardium occidentale) apple juice and bagasse from Colombian varieties

Cashew nut production generates large amounts of cashew apple as residue. In Colombia, cashew cultivation is increasing together with the concerns on residue management. The objective of this study was to provide the first chemical, physical and thermal decomposition characterization of cashew apple from Colombian varieties harvested in Vichada, Colombia. This characterization was focused to identify the important bioactive and natural compounds that can be further valorized in the formulation of food, nutraceuticals, and pharmacological products. The results obtained in this study are helpful to portray the cashew apple as a potential by-product due to its renewable nature and valuable composition, instead of seeing it just as an agricultural residue. For that, cashew apples of Regional 8315 and Mapiria varieties were studied. The natural juice (cashew apple juice) that was extracted from the cashew apples and the remanent solids (cashew apple bagasse) were separately analyzed. The HPLC analytical technique was used to determine the concentration of bioactive compounds, structural carbohydrates, and soluble sugars that constitute this biomass. Spectrophotometric techniques were used to determine the concentration of tannins, carotenoids, and total polyphenols. Mineral content and antioxidant activity (DPPH and ABTS assays) were determined in the biomass. Also, the thermal decomposition under an inert atmosphere or pyrolysis was performed on cashew apple bagasse. The varieties of cashew apple studied in this work showed similar content of bioactive compounds, total phenolic content, and structural carbohydrates. However, the Mapiria variety showed values slightly higher than the Regional 8315. Regarding cashew apple juice, it is rich in tannins and ascorbic acid with values of 191 mg/100 mL and 70 mg/100 mL, respectively, for Mapiria variety. Additionally, the principal reservoir of bioactive compounds and constitutive carbohydrates was the cashew apple bagasse. About 50 wt.% of it was composed of cellulose and hemicellulose. Also, in the bagasse, the ascorbic acid content was in a range of 180–200 mg/100 g, which is higher than other fruits and vegetables. Moreover, alkaloids were identified in cashew apples. The maximum value of antioxidant activity (DPPH assay: 405 TEs/g) was observed in the bagasse of Mapiria variety. The bagasse thermal decomposition started around 150 °C when the structural carbohydrates and other constitutive substances started to degrade. After thermogravimetric analysis, a remanent of 20% of the initial weight suggested the formation of a rich-carbon solid, which could correspond to biochar. Therefore, the cashew apple harvested in Vichada is a valuable reservoir of a wide range of biomolecules that potentially could be valorized into energy, foods, and pharmacologic applications. Nevertheless, future work is necessary to describe the complex compounds of this residual biomass that are still unknown.

Circulating vitamin C and D concentrations and risk of dental caries and periodontitis: A Mendelian randomization study

AIM

This Mendelian randomization (MR) study was performed to explore the causal relationship among circulating vitamin C and D levels, dental caries, and periodontitis.

MATERIALS AND METHODS

MR analyses were conducted with the inverse variance weighted (IVW) method, weighted median, MR-Egger approaches, and MR-robust adjusted profile score method to assess the causal relationships between circulating vitamin C and D concentrations and dental caries, the number of remaining natural permanent teeth in the mouth (N teeth), and periodontitis.

RESULTS

We found potential causal association of circulating vitamin D concentrations with N teeth (β = 0.085; 95% confidence interval: 0.019 to 0.150; p = .012) based on the IVW method. No significant causal relationship between circulating vitamin D levels and dental caries and periodontitis was observed. Similarly, no evidence supported a causal relationship between circulating vitamin C concentrations and the risk of dental caries, N teeth, and periodontitis.

CONCLUSIONS

There is no obvious evidence suggesting a causal relationship among circulating vitamin D, dental caries, and periodontitis, drawing into question the mechanism for any association with N teeth. Additionally, there is insufficient power to detect small effects in vitamin C levels and caries and periodontitis.

Enhancement of Antiviral T-Cell Responses by Vitamin C Suggests New Strategies to Improve Manufacturing of Virus-Specific T Cells for Adoptive Immunotherapy

Allogeneic and autologous transplantation of hematopoietic stem cells (HSCT) are being routinely used to treat patients with leukemia and lymphoma. Due to the required immunosuppression after stem cell transplantation, infection and reactivation by viruses are life-threatening complications. In recent years, adoptive transfer using virus-specific T cells (VSTs) has emerged as alternative to conventional therapies. Since vitamins are described to influence the immune system and its cellular components, the aim of this study was to examine whether vitamins modulate VST function and thereby enable an improvement of therapy. For that, we investigated the impact of vitamin C and D on the functionality of cytomegalovirus (CMV)-specific T cells isolated from CMV-seropositive healthy donors. We were able to show that vitamin C increases the expansion and activation state of CMV-specific T cells, and an increased influence of vitamin C was observed on cells isolated from male donors and donors above 40 years of age. A higher frequency of the terminally differentiated effector memory CD8+ T-cell population in these donors indicates a connection between these cells and the enhanced response to vitamin C. Thus, here we provide insights into the impact of vitamin C on cytotoxic T cells as well as possible additional selection criteria and strategies to improve VST functionality.

Advances on the Antioxidant Activity of a Phytocomplex Product Containing Berry Extracts from Romanian Spontaneous Flora

The present study aimed to evaluate the antioxidant properties of a phytocomplex product obtained using 10% hydroalcoholic extractive solutions, in equal proportions, from Ribes nigrum, Rubus idaeus, Rubus fruticosus and Fragaria moschata fresh fruits harvested from the spontaneous flora of Romania. These plant products were recognized for their rich antioxidant content. The phytochemical profile was assessed using HPLC chromatography and UV-Vis spectrometry. The obtained results highlighted the presence of complex bioactive compounds with antioxidant actions, namely anthocyanins, proanthocyanins and vitamin C. The antioxidant actions of the hydroalcoholic extractive solutions and the phytocomplex product were evaluated using chemiluminescence, electrochemical and superoxide dismutase (SOD) methods. The experimental results showed evident antioxidant activity in both the hydroalcoholic extracts and the phytocomplex product.

Vitamin C intake and multiple health outcomes: an umbrella review of systematic reviews and meta-analyses

The purpose of this article was to assess the existing systematic reviews and meta-analyses for the association between vitamin C intake and multiple health outcomes. A total of 76 meta-analyses (51 papers) of randomised controlled trials and observational studies with 63 unique health outcomes were identified. Dose-response analysis showed that vitamin C intake was associated with reduced risk of all-cause mortality, cardiovascular disease (CVD), oesophageal cancer, gastric cancer, cervical cancer and lung cancer with an increment of 50-100 mg per day. Beneficial associations were also identified for respiratory, neurological, ophthalmologic, musculoskeletal, renal and dental outcomes. Harmful associations were found for breast cancer and kidney stones for vitamin C supplement intake. The benefits of vitamin C intake outweigh the disadvantages for a range of health outcomes. However, the recommendation of vitamin C supplements needs to be cautious. More prospective studies and well-designed randomised controlled trials (RCTs) are needed.

Biological Synthesis of Bioactive Gold Nanoparticles from Inonotus obliquus for Dual Chemo-Photothermal Effects against Human Brain Cancer Cells

The possibility for an ecologically friendly and simple production of gold nanoparticles (AuNPs) with Chaga mushroom (Inonotus obliquus) (Ch-AuNPs) is presented in this study. Chaga extract’s reducing potential was evaluated at varied concentrations and temperatures. The nanoparticles synthesized were all under 20 nm in size, as measured by TEM, which is a commendable result for a spontaneous synthesis method utilizing a biological source. The Ch-AuNPs showed anti-cancer chemotherapeutic effects on human brain cancer cells which is attributed to the biofunctionalization of the AuNPs with Chaga bioactive components during the synthesis process. Further, the photothermal ablation capability of the as-prepared gold nanoparticles on human brain cancer cells was investigated. It was found that the NIR-laser induced thermal ablation of cancer cells was effective in eliminating over 80% of the cells. This research projects the Ch-AuNPs as promising, dual modal (chemo-photothermal) therapeutic candidates for anti-cancer applications.

Underutilized Fruit Crops of Indian Arid and Semi-Arid Regions: Importance, Conservation and Utilization Strategies

Nowadays, there is a large demand for nutrient-dense fruits to promote nutritional and metabolic human health. The production of commercial fruit crops is becoming progressively input-dependent to cope with the losses caused by biotic and abiotic stresses. A wide variety of underutilized crops, which are neither commercially cultivated nor traded on a large scale, are mainly grown, commercialized and consumed locally. These underutilized fruits have many advantages in terms of ease to grow, hardiness and resilience to climate changes compared to the major commercially grown crops. In addition, they are exceptionally rich in important phytochemicals and have medicinal value. Hence, their consumption may help to meet the nutritional needs of rural populations, such as those living in fragile arid and semi-arid regions around the world. In addition, local people are well aware of the nutritional and medicinal properties of these crops. Therefore, emphasis must be given to the rigorous study of the conservation and the nutritional characterization of these crops so that the future food basket may be widened for enhancing its functional and nutritional values. In this review, we described the ethnobotany, medicinal and nutritional values, biodiversity conservation and utilization strategies of 19 climate-resilient important, underutilized fruit crops of arid and semi-arid regions (Indian jujube, Indian gooseberry, lasora, bael, kair, karonda, tamarind, wood apple, custard apple, jamun, jharber, mahua, pilu, khejri, mulberry, chironji, manila tamarind, timroo, khirni).