Effects of quercetin and l-ascorbic acid on heterocyclic amines and advanced glycation end products production in roasted eel and lipid-mediated inhibition mechanism analysis

Eel is a commercially important marine fish, frequently featured as sushi or roasted preparations. This study determined the formation of heterocyclic amines (HAs) and advanced glycation end products (AGEs) in roasted eel and evaluated the inhibitory mechanism of quercetin and l-ascorbic acid on their formation. The results indicate a respective reduction of 75.07% and 84.72% in total HAs, alongside a decline of 23.03% and 39.14% in AGEs. Additionally, fundamental parameters of roasted eel, lipid oxidation indicators and precursors were measured to elucidate the mechanisms and impact of natural antioxidants on HAs and AGEs formation in roasted eel. Furthermore, endeavors were made to probe into the molecular mechanisms governing the influence of key differential lipids on the generation of HAs and AGEs through lipid-mics analysis. This research emphasizes the potential of natural antioxidants in preventing harmful substances formation during eel thermal processing, which is helpful to food manufacturers for healthier food production.

Orange peel-derived carbon dots/Cu-MOF nanohybrid for fluorescence determination of l-ascorbic acid and Fe3. Anal Chim Acta 2024;1287:342066. [PMID: 38182373 DOI: 10.1016/j.aca.2023.342066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Recycling and reuse of biomass waste in synthesis of nanomaterials have recently received much attention as an effective solution for environmental protection and sustainable development. Herein, nitrogen-doped carbon dots (N-CDs) with blue emission were synthesized from the orange peels as a precursor through a simple hydrothermal method and then, modified with ethylenediamine tetraacetic acid (N-CD@EDTA). The N-CD@EDTA was embedded as a fluorophore in Cu-based metal-organic framework (MOF-199) structure (N-CD@EDTA/MOF-199) to construct fluorescence sensor toward l-ascorbic acid (L-AA) determination. The N-CD@EDTA/MOF-199 nanohybrid significantly and selectively turned on toward L-AA determination during the fluorimetric experiments. Under optimal conditions, the probe showed a suitable linear response in the concentration range of 10 nM-100 μM with a low limit of detection (LOD) of 8.6 nM and high sensitivity of 0.201 μM-1. The possible mechanism of recognition and adsorption, including the reduction of Cu 2+ nodes in the MOF-199 structure in the presence of L-AA and the release of trapped N-CD@EDTA into the solution, was explored. Moreover, the N-CD@EDTA/MOF-199/L-AA (100 μM) system was further applied as a fluorescent "on-off" sensor for Fe3+ determination with a LOD of 1.15 μM. The proposed probe was successfully used in orange juice and water samples to determine L-AA and Fe3+ with satisfactory recovery, which displays the promising capability of sensor in real samples. The recoveries obtained by suggested method are consistent with that obtained from high performance liquid chromatography (HPLC) and atomic absorption spectroscopy which confirm the favorable characteristic of the sensor for accurate determination of L-AA and Fe3+ in practical applications.

Soil-phase immobilization of hexavalent chromium using L-ascorbic acid - kinetics, process optimization, and phytotoxicity studies

l-ascorbic acid is found to be an effective and environmentally friendly reagent for remediation of Cr(VI)-contaminated soil. Soil-phase batch kinetics experiments elucidated the effects of chromium(VI) and l-ascorbic acid dosing, pH, soil-to-water ratio, and temperature on Cr(VI) reduction. An extended reductive environment was observed at a lower pH range, possibly due to ligand oxidation of several reactive intermediates. The kinetic data were fitted into a second-order rate model, and the rate constant was evaluated. A reaction mechanism was proposed. Reduction was substantially complete within about 3 h at natural pH conditions at an appropriate dosing of the reagent, and any residual Cr(VI) is reduced by the remaining ascorbic acid during aging of the soil. The reagent worked much better than other organic reductants reported in the literature. The rate constant correlated linearly with the soil-to-water ratio, while its logarithm correlated linearly with pH within the specified range. The reduction was primarily attributed to the presence of carboxylic, hydroxyl, and carbonyl groups in the ascorbic acid molecule, as confirmed by FTIR and XRD analysis. Medium-term stability experiments suggest that treatment with l-ascorbic acid significantly decreased leaching concentrations of Cr(VI) and total Cr which remained stable for 75 d. Ecological studies have shown that remediated soil promotes plant growth and increases earthworm survival rates, thus negating the emergence of any secondary pollutants. Response surface methodology (RSM) was used to investigate the relationship between Cr(VI) reduction and experimental parameters and to determine the optimum values. About 98.8 % reduction was achieved, which was consistent with the calculated optimal value. The study provides new insights into the use of l-ascorbic acid for sustainable remediation of Cr(VI)-contaminated soil. The optimum process conditions and the rate data obtained in this study are expected to be useful for the process design of a remediation facility for Cr(VI)-contaminated soil.

Ag2S QDs integration with MnO2 nanosheets for the sensitive detection of Cr (VI) via the redox reaction induced photoelectrochemical variation

The heavy metal Cr (VI) will remain, accumulate, and migrate after entering the environment or ecosystem, causing serious harm to the environment. Here, a photoelectrochemical sensor was developed for Cr (VI), utilizing the Ag₂S quantum dots (QDs) and MnO₂ nanosheets as photoactive components. By introducing Ag₂S QDs with a narrow gap, a staggered energy level match is created which effectively prevents the carrier recombination in MnO₂ nanosheets, resulting in an enhanced photocurrent response. In the presence of the electron donor, l-ascorbic acid (AA), the photocurrent of the Ag₂S QDs and MnO₂ nanosheets modified photoelectrode is further enhanced. As AA has the ability to convert Cr (VI) to Cr (Ⅲ), the photocurrent may decline due to the decrease in the electron donors when Cr (VI) is added. This phenomenon can be utilized for the sensitive detection of Cr (VI) over a wider linear range (100 pM-30 μM) with a lower detection limit of 6.46 pM (S/N = 3). This work using the strategy that the targets induced the variations of the electron donor shows the advantages of good sensitivity and nice selectivity. The sensor holds many advantages such as simple fabrication process, economical material expense, and consistent photocurrent signals. It also holds significant potential for environmental monitoring and serves as a practical photoelectric sensing approach for detecting Cr (VI).

L-ascorbic acid could ameliorate the damage of myocardial microvascular endothelial cell caused by hypoxia-reoxygenation via targeting HMGB1

In this study, we intend to explore the potential function of l-ascorbic acid in hypoxia-reoxygenation (H/R)-induced damage of CMECs and its related molecular mechanism. With different concentrations of l-ascorbic acid treatment, the proliferation, migration, inflammation and autophagy of cardiac microvascular endothelial cells (CMECs) were determined by several biological experiments. Si-HMGB1 transfection was used to reduce HMGB1 expression and to detect the function of HMGB1 in H/R-induced damage of CMECs. Under H/R condition, the proliferation and migration abilities of CMECs were reduced, and the inflammation and autophagy of CMECs were increased. Whereas, after l-ascorbic acid treatment, the reduction in the proliferation and migration of CMECs, as well as the increase in the inflammation and autophagy of CMECs induced by H/R were reversely altered. HMGB1 was confirmed as a specific target of l-ascorbic acid, and si-HMGB1 treatment strengthened the beneficial effect of l-ascorbic acid on H/R-induced damage of CMECs, followed by further reduction in the proliferation and migration abilities of CMECs, as well as the increase in the inflammation and autophagy of CMECs. Few studies have reported the function of l-ascorbic acid in myocardial ischemia on CMECs, but our experimental data showed that l-ascorbic acid treatment could ameliorate the H/R-induced damage of CMECs by regulating HMGB1 expression.

Solid-in-oil nanodispersion as a novel topical transdermal delivery to enhance stability and skin permeation and retention of hydrophilic drugs l-ascorbic acid

l-ascorbic acid （Vitamin C, VC） is the most abundant antioxidant in human skin. But its poor penetration into the skin and unstability limit the application. The aim of the study was to promote the topical skin permeation and retention of VC, increase the stability as well as effectiveness by a novel solid in oil nanodispersion. In the nanodispersions system, nano-sized particles of hydrophilic molecules are dispersed in an oil vehicle with the assistance of hydrophobic surfactants. The optimized formula composed of O170 and S1570 (12.5:1, w/w) showed high EE% of 98% and good stability. FTIR analysis confirmed that there may be hydrogen bond between VC and surfactants. The results of DSC, and XRD revealed that the drug was successfully encapsulated in the surfactants, which maintained the stability of drug. By analyzing and fitting the release data in vitro, the drug release mechanism of SONDs was predicted as a multi-dynamic model. Skin permeation of VC was improved 3.43-fold for SONDs compared with VC aqueous solution, highlighting that the lipophilicity and nano size of the carrier more easily penetrated into the skin. Finally, the photoaging study revealed that topical application of VC-SONDs provided the highest skin protection compared UV and VC aqueous solution treated group which was evident by the normal thick epidermal morphology, no obvious melanocytes and the densely arranged dermal elastic fibers. These results demonstrated that the solid-in-oil nanodispersions may be a potential transdermal delivery system for hydrophilic bioactive ingredients.

Influences of l-ascorbic acid on cytotoxic, biochemical, and genotoxic damages caused by copper II oxide nanoparticles in the rainbow trout gonad cells-2

In parallel with the raising use of copper oxide nanoparticles (CuO NPs) in various industrial and commercial practices, scientific reports on their release to the environment and toxicity are increasing. The toxicity of CuO NPs is mostly based on their oxidative stress. Therefore, it is necessary to investigate the efficacy of well-known therapeutic agents as antioxidants against CuO NPs damage. This study aimed to investigate the mechanism of this damage and to display whether l-ascorbic acid could preserve against the cell toxicities induced by CuO NPs in the rainbow trout gonad cells-2 (RTG-2). While CuO NPs treatment significantly diminished cell viability, the l-ascorbic acid supplement reversed this. l-ascorbic acid treatment reversed the changes in expressions of sod1, sod2, gpx1a, and gpx4b genes while playing a supportive role in the changes in the expression of the cat gene induced by CuO NPs treatment. Moreover, CuO NPs treatment caused an upregulation in the expressions of growth-related genes (gh1, igf1, and igf2) and l-ascorbic acid treatment further increased these effects. CuO NPs treatment significantly up-regulated the expression of the gapdh gene (glycolytic enzyme gene) compared to the control group, and l-ascorbic acid treatment significantly down-regulated the expression of the gapdh gene compared to CuO NPs treatment. The genotoxicity test demonstrated that l-ascorbic acid treatment increased the genotoxic effect caused by CuO NPs by acting as a co-mutagen. Based on the findings, l-ascorbic acid has the potential to be sometimes inhibitory and sometimes supportive of cellular mechanisms caused by CuO NPs.

Microbial Interactions in a Vitamin C Industrial Fermentation System: Novel Insights and Perspectives

In industrial production, the precursor of l-ascorbic acid (L-AA, also referred to as vitamin C), 2-keto-l-gulonic acid (2-KLG), is mainly produced using a classic two-step fermentation process performed by Gluconobacter oxydans, Bacillus megaterium, and Ketogulonicigenium vulgare. In the second step of the two-step fermentation process, the microbial consortium of K. vulgare and B. megaterium is used to achieve 2-KLG production. K. vulgare can transform l-sorbose to 2-KLG, but the yield of 2-KLG is much lower in the monoculture than in the coculture fermentation system. The relationship between the two strains is too diverse to analyze and has been a hot topic in the field of vitamin C fermentation. With the development of omics technology, the relationships between the two strains are well explained; nevertheless, the cell-cell communication is unclear. In this review, based on current omics results, the interactions between the two strains are summarized, and the potential cell-cell communications between the two strains are discussed, which will shed a light on the further understanding of synthetic consortia.

Bioconversion of cyanobacteria by black soldier fly larvae (Hermetia illucens L.): Enhancement by antioxidants

Cyanobacterial blooms have been a global environmental problem for decades. Bioconversion by black soldier fly larvae (BSFL) has been widely reported to be a clean and efficient method to remove organic pollutants. In this study, BSFL bioconversion was used to treat cyanobacterial blooms. Antioxidants (a mixture of l-ascorbic acid [180 mg/kg fresh feed] and α-tocopherol [360 mg/kg fresh feed]) were added to compare bioconversion performance against a non-supplemented group. With increasing proportions of cyanobacteria (0%-25% dry mass), the bioconversion efficiency of the antioxidant group improved significantly compared to the control group, and the survival rate of larvae rose from 96.50-45.50% to 98.00-55.83% with antioxidant addition. The toxic effects of exogenous anti-nutrients could be reduced by the antioxidants through inactivation of trypsin inhibitor and enhancement of the microcystin-LR degradation rate. Overall, the BSFL bioremediation capacity was improved with addition of exogenous antioxidants, verifying both the effects and mechanism of antioxidant addition in promoting the bioconversion of cyanobacteria by BSFL and providing a basis for future application and study.

The study of volatile products formation from the self-degradation of l-ascorbic acid in hot compressed water

The volatile products (VPs) formation from the self-degradation of l-ascorbic acid (ASA) in hot compressed water (HCW) was investigated with different reaction parameters, such as time, temperature, pH and ratio of ASA/water. The results showed that various reaction parameters had varying degrees of influence on the reaction, while the most significant effect factor was the initial pH of the solution. Furfural was the major product under acidic conditions, while furan derivatives were the main products under alkaline conditions. The above results showed that pH played the dominant role for yields and distribution of VPs in HCW. In the HCW system, the yields and classifications of VPs and conversion rate of ASA were not the same as those of VPs and ASA under traditional conditions. Based on the experimental results, the possible formation mechanism of VPs from the self-degradation of ASA was proposed in HCW.

Synthesis of l-ascorbic acid-amino acid-norcantharidin conjugates and their biological activity evaluation in vitro

Three components of L-ascorbic acid, amino acid and functionalized norcantharidins were constructed together in several steps to form 42 norcantharidin derivatives in a high yield. The structure of these synthesized l-ascorbic acid-amino acid-norcantharidin conjugates are determined by ¹HNMR, ¹³CNMR and MS spectrum. The results showed that compounds 6e, 6g, 6j, 6l, 6m, 6b, 6e, 6i, and 6n showed high cytotoxicity to HepG2 and compounds 6b, 6e-g, 6l, 6n, 7b, 7d, 7h, 7i, 7n, 8g, 8i exhibited high cytotoxicity to SW480; Meanwhile, besides 6b, 6e, 6g, and 6k, the other compounds showed less toxic to LO2 at a concentration of 50 μg/mg after 72 h. Compound 6g can induce Mφ-type macrophages derived from mouse bone marrow to polarize to M1-type macrophages.

Enzymatic Production of Ascorbic Acid-2-Phosphate by Engineered Pseudomonas aeruginosa Acid Phosphatase

l-Ascorbic acid-2-phosphate (AsA-2P) is stable in aqueous solution and at high temperatures and is widely used in foods, pharmaceuticals, cosmetics, and fodders; however, practical application of enzymatic synthesis methods to promote industrial-scale production of AsA-2P remains a major challenge. In this study, we enhanced the phosphorylation efficiency of Pseudomonas aeruginosa acid phosphatase (APase; EC 3.1.3.2) for AsA-2P production via protein engineering. Among the mutants obtained, we selected the most efficient mutant (Var₅; G125E/D135T/S136N), which exhibited an increased k_cat of 18.6 s^-1 and a K_m for AsA of 223.9 mM. In addition, Var₅ exhibited a maximum enzyme activity of 2080.4 U/L after 10 h of fermentation, which was 80% higher than the wild-type enzyme. Furthermore, under optimal conditions, Var₅ showed a maximal conversion of 48.6% and achieved a final AsA-2P titer of 61.5 g/L at 8 h, which is considerably higher than that reported for other similar biocatalytic approaches. These findings demonstrate the potential of this method for the large-scale production of AsA-2P.

Simultaneous transformation of five vectors in Gluconobacter oxydans

Gluconobacter oxydans is an obligate Gram-negative bacterium that belongs to the family Acetobacteraceae. It is one of the most frequently used microorganisms in industrial biotechnology to produce chemicals related to incomplete oxidation. However, the fine-tuning of G. oxydans is hampered by the lack of efficient genetic tools to enable sophisticated metabolic manipulations. Thus, a series of shuttle vectors for G. oxydans inspired by a series of wild-type plasmids in different G. oxydans strains were constructed. Fifteen shuttle vectors were employed to express mCherry in G. oxydans WSH-003 using the replication origin of these wild-type plasmids. Among them, the intensity of fluorescent proteins expressed by p15-K-mCherry was about 10 times that of fluorescent proteins expressed by p5-K-mCherry. Quantitative real-time polymerase chain reaction showed that the relative copy number of p15-K-mCherry reached 19 and had high stability. In contrast, some of the plasmids had a relative copy number of less than 10. The co-expression of multiple shuttle vectors revealed five shuttle vectors that could be transformed into G. oxydans WSH-003 and could express five different fluorescent proteins. The shuttle vectors will facilitate genetic operations for Gluconobacter strains to produce useful compounds more efficiently.

Heterologous Expression of Cyclodextrin Glycosyltransferase my20 in Escherichia coli and Its Application in 2-O-α-D-Glucopyranosyl-L-Ascorbic Acid Production

In this study, the cgt gene my20, which encodes cyclodextrin glycosyltransferase (CGTase) and was obtained by the metagenome sequencing of marine microorganisms from the Mariana Trench, was codon optimized and connected to pET-24a for heterologous expression in Escherichia coli BL21(DE3). Through shaking flask fermentation, the optimized condition for recombinant CGTase expression was identified as 20°C for 18 h with 0.4 mM of isopropyl β-D-L-thiogalactopyranoside. The recombinant CGTase was purified by Ni²⁺-NTA resin, and the optimum pH and temperature were identified as pH 7 and 80°C, respectively. Activity was stable over wide temperature and pH ranges. After purification by Ni²⁺-NTA resin, the specific activity of the CGTase was 63.3 U/mg after 67.3-fold purification, with a final yield of 43.7%. In addition, the enzyme was used to transform L-ascorbic acid into 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G). The maximal AA-2G production reached 28 g/L, at 40°C, pH 4, 24 h reaction time, 50 g/L donor concentration, and 50 U/g enzyme dosage. The superior properties of recombinant CGTase strongly facilitate the industrial production of AA-2G.

High-dose vitamin C intravenous infusion in the treatment of patients with COVID-19: A protocol for systematic review and meta-analysis

BACKGROUND

Patients infected with a virus usually lack vitamin C. High-dose vitamin C has an antiviral effect, and has been used by several researchers to treat COVID-19 by intravenous infusion, achieving good results. However, the efficacy and safety of vitamin C in the treatment of patients with COVID-19 remain unclear. Thus, the aim of the present study was to investigate the efficacy of high-dose vitamin C infusion in the treatment of patients with COVID-19.

METHODS

Electronic databases were searched, including PubMed, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science, China National Knowledge Infrastructure database, Chinese Wanfang database, and Chinese Biomedical Literature database. The aim was to collect randomized controlled trials of high-dose vitamin C infusion in the treatment of patients with COVID-19, with the retrieval time being from the establishment of the database to March 2021. In accordance with the pre-designed inclusion/exclusion criteria, all data were extracted independently by 2 researchers. To assess the risk bias in the studies, the Cochrane collaboration's tool for assessing risk of bias was used to assess the risk bias in the studies, while meta-analysis was performed using Revman 5.3 software.

RESULTS

In the present study, a high-quality comprehensive evaluation is provided of high-dose vitamin C infusion in the treatment of patients with COVID-19.

CONCLUSION

Further convincing evidence for the clinical treatment of COVID-19 is provided, in addition to evidence-based guidance for clinical practice.

PROSPERO REGISTRATION NUMBER

CRD42021246342.

Polyhydroxy Ester Stabilized Perovskite for Low Noise and Large Linear Dynamic Range of Self-Powered Photodetectors

Solution-processed perovskites as emerging semiconductors have achieved unprecedented milestones in sensor optoelectric devices. Stability along with the device noise issues are the major obstacle for photodetectors to compete with the traditional devices. Here, we demonstrated that l-ascorbic acid (l-AA) as a polyhydroxy ester can coordinate with the amino group of formamidine cations (FA⁺) through multiple hydrogen bond interactions to stabilize the perovskite, which protect the FA⁺ ions from nucleophile attack and effectively suppress the degradation of FA⁺ ions, improving the perovskite stability and suppressing the device noise to below 0.3 pA Hz^-1/2 with a large linear dynamic range of 239 dB. The dual functions of l-AA enable the perovskite photodetector to have a high detectivity of 10¹² Jones. The self-powered device works with no energy consumption and maintains an undegraded performance over 1200 h of inspection at ambient conditions, which is promising for infrastructure construction, signal sensing, and real-time information delivery.

Quantitative Spatiotemporal Mapping of Lipid and Protein Oxidation in Mayonnaise

Lipid oxidation in food emulsions is mediated by emulsifiers in the water phase and at the oil–water interface. To unravel the physico-chemical mechanisms and to obtain local lipid and protein oxidation rates, we used confocal laser scanning microscopy (CLSM), thereby monitoring changes in both the fluorescence emission of a lipophilic dye BODIPY 665/676 and protein auto-fluorescence. Our data show that the removal of lipid-soluble antioxidants from mayonnaises promotes lipid oxidation within oil droplets as well as protein oxidation at the oil–water interface. Furthermore, we demonstrate that ascorbic acid acts as either a lipid antioxidant or pro-oxidant depending on the presence of lipid-soluble antioxidants. The effects of antioxidant formulation on local lipid and protein oxidation rates were all statistically significant (p < 0.0001). The observed protein oxidation at the oil–water interface was spatially heterogeneous, which is in line with the heterogeneous distribution of lipoprotein granules from the egg yolk used for emulsification. The impact of the droplet size on local lipid and protein oxidation rates was significant (p < 0.0001) but minor compared to the effects of ascorbic acid addition and lipid-soluble antioxidant depletion. The presented results demonstrate that CLSM can be applied for unraveling the roles of colloidal structure and transport in mediating lipid oxidation in complex food emulsions.

A cocrystal of L-ascorbic acid with picolinic acid: the role of O-H...O, N-H...O and C-H...O hydrogen bonds and L-ascorbic acid conformation in structure stabilization

A new 1:1 cocrystal (L-Asc-Pic) of L-ascorbic acid (vitamin C) with picolinic acid was prepared as a powder and as single crystals. The crystal structure was solved and refined from single-crystal X-ray diffraction (SCXRD) data collected at 293 (2) and 100 (2) K. The samples of the L-Asc-Pic cocrystal were characterized by elemental (HCNS) analysis and titrimetric methods, TG/DTG/DSC, and IR and Raman spectroscopy. The asymmetric unit comprises a picolinic acid zwitterion and an L-ascorbic acid molecule. The stabilization energy of intermolecular interactions involving hydrogen bonds, the vibrational spectrum and the energies of the frontier molecular orbitals were calculated using the GAUSSIAN09 and the CrystalExplorer17 programs. The charge distribution on the atoms of the L-Asc-Pic cocrystal, L-ascorbic acid itself and its 12 known cocrystals (structures from Version 5.40 of the Cambridge Structural Database) were calculated by the methods of Mulliken, Voronoi and Hirshfeld charge analyses (ADF) at the bp86/TZ2P+ level of theory. The total effective charges and conformations of the L-ascorbic acid molecules in the new and previously reported cocrystals were compared with those of the two symmetry-independent molecules in the crystals of L-ascorbic acid. A correlation between molecular conformation and its effective charge is discussed.

Ni and Zn co-substituted Co(CO3)0.5OH self-assembled flowers array for asymmetric supercapacitors

The supercapacitive performance of high-rate capacity and long-term cycling stability is still a big challenge for electroactive materials. Herein, Ni and Zn co-substituted Co carbonate hydroxide (NiZn-CoCH) flowers array is self-assembled on nickel foams (NFs) using l-ascorbic acid as a nanostructure inducer. The NiZn-CoCH flowers, consisting of silk-like nanosheets, are deservedly large electrode-electrolyte contact area and suitable ion-diffusion channel. The nanostructure and Ni and Zn co-substitution significantly improve energy storage performance. This electrode exhibits a high specific capacitance of 2020.8 F g^-1 at 1 A g^-1 with high-rate capacity (remain 80.2% at 10 A g^-1) and 5000-cycle stability (almost unchanged after 1500 cycles at 10 A g^-1). Additionally, an assembled asymmetric supercapacitor (ASC) device of NiZn-CoCH//activated carbon (AC) achieves a high energy density of 29.6 Wh kg^-1 at a power density of 375 W kg^-1 and only a 0.5% decrease of the capacitance after 2500 cycles. This facile and novel preparation method, using l-ascorbic acid, may be promising for industrial production of electroactive materials for the high-performance energy storage and conversion devices.

E8002 Inhibits Peripheral Nerve Adhesion by Enhancing Fibrinolysis of l-Ascorbic Acid in a Rat Sciatic Nerve Model

Perineural adhesions leading to neuropathy are one of the most undesirable consequences of peripheral nerve surgery. However, there are currently no widely used compounds with anti-adhesive effects in the field of peripheral nerve surgery. E8002 is a novel, anti-adhesive, multi-layer membrane that contains L-ascorbic acid (AA). Here, we investigated the effect and mechanism of E8002 in a rat sciatic nerve adhesion model. A total of 21 rats were used. Six weeks after surgery, macroscopic adhesion scores were significantly lower in the E8002 group (adhesion procedure followed by nerve wrapping with E8002) compared to the E8002 AA(−) group (adhesion procedure followed by nerve wrapping with the E8002 membrane excluding AA) and adhesion group (adhesion procedure but no treatment). Correspondingly, a microscopic examination revealed prominent scar tissue in the E8002 AA(−) and adhesion groups. Furthermore, an in vitro study using human blood samples showed that AA enhanced tissue-type, plasminogen activator-mediated fibrinolysis. Altogether, these results suggest that E8002 may exert an anti-adhesive action via AA and the regulation of fibrinolysis.

Improve the developmental competence of porcine oocytes from small antral follicles by pre-maturation culture method

The oocytes from small antral follicle have low developmental potential to reach blastocyst due to incomplete cytoplasmic maturation during in vitro maturation (IVM). Thus, we developed an in vitro culture system for porcine oocytes derived from small antral follicles with l-ascorbic acid supplement during pre-maturation (pre-IVM) to support their development to blastocyst stage. Besides that, how l-ascorbic acid effect on the developmental competence of porcine oocytes with a special focus on histone modifications will be elucidated. The in vitro culture process consisted of two steps. The first step is 22 h of pre-IVM and the second step is 42 h of IVM. We utilized dibutyryl-cyclicAMP (dbcAMP) with L-ascorbic supplement during pre-IVM. Based on the result of this procedure, we proposed that the best culture condition in which hormone human chorionic gonadotropin (hCG) be added during the last 7 h of pre-IVM and continued culture to complete IVM. We observed that, in this culture system, the meiotic competence of porcine oocytes derived from small follicles was as high as those derived from large follicles after undergoing IVM. In addition, our study suggested that l-ascorbic acid supplementation at 100 μg/mL sharply enhanced the developmental potential of porcine oocytes. Interestingly, oocytes from small antral follicles treated with l-ascorbic acid could obtain the blastocyst quantity and quality as high as that of large antral follicles. The treated groups showed a significantly higher number of blastomeres compared to those in non-treated groups in both small and large follicle groups. Besides that, = The increasing levels of acetylation of histone H3 at lysine 9 (H3K9) and methylation of histone H3 at lysine 4 (H3K4) in blastocyst derived from small and large antral follicle under the present of l-ascrobic acid lead to a significant positive effect on the developmental competence and improvement in quality of porcine embryos.

A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

A simple, low cost, and "green" method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO₂ aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO₂ compound. The pseudocapacitance contribution from the resulting embedded MoO₂ microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO₂ particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

Therapeutic Perspective of Vitamin C and Its Derivatives

l-Ascorbic acid (ASA), vitamin C, is a ubiquitous carbohydrate-like compound that has an essential role in a number of cellular processes, such as collagen synthesis, cellular oxidation, and various hydroxylation reactions. ASA is a biomolecule of critical importance for protection of cellular components against oxidative damage caused by toxic free radicals and other reactive oxygen species (ROS) that are involved in the development of various types of chronic diseases. Vitamin C has a switchover role from being an antioxidant in physiological conditions to a prooxidant under pathologic conditions. Moreover, some l-ascorbic acid derivatives exhibit strong and selective antitumor and antiviral activity. This review emphasizes the advances on diverse and potent biological profiles of l-ascorbic acid and its derivatives, and their perspective in the development of new bioactive chemical entities in the future. The work is primarily addressed at antioxidant, anticancer, and antiviral potencies of l-ascorbic acid and compounds containing its butenolide structural motif.

Partial charge transfer in the salt co-crystal of l-ascorbic acid and 4,4'-bi-pyridine

In the title 1:2 co-crystal, l-ascorbic acid (LAA) and 4,4′-bi­pyridine (bpy) co-crystallize with two mol­ecules of LAA, and one mol­ecule of bpy in the asymmetric unit. The structure was modeled in two parts due to possible proton transfer from LAA to the corresponding side of the bpy mol­ecule having an occupancy of approximately 0.25 and part 2 with an occupancy of approximately 0.75.

In the title 1:2 co-crystal, C₁₀H₉N₂⁺·(C₆H_7.75O₆·C₆H_7.25O₆)⁻, l-ascorbic acid (LAA) and 4,4′-bi­pyridine (BPy) co-crystallize in the chiral space group P2₁ with two mol­ecules of LAA, and one mol­ecule of bpy in the asymmetric unit. The structure was modeled in two parts due to possible proton transfer from LAA to the corresponding side of the bpy mol­ecule having an occupancy of approximately 0.25 and part 2 with an occupancy of approximately 0.75. In this structure, LAA forms hydrogen bonds with neighboring LAA mol­ecules, forming extended sheets of LAA mol­ecules which are bridged by bpy mol­ecules. A comparison to a related and previously published co-crystal of LAA and 3-bromo-4-pyridone is presented.

Ameliorating effects of dietary mixture of Withania somnifera root extract and vitamin C in Labeo rohita against low pH and waterborne iron stresses

The present study was conducted to elucidate the possible effect of a combination of Withania somnifera (Ashwagandha) root extract and dietary l-ascorbic acid (vitamin C) on the immune responses and survivability in Labeo rohita fingerlings against low pH and waterborne iron toxicity. Four diets were prepared containing 0% (control), 0.01% (T1), 0.1% (T2) and 1.0% (T3) of a combination of Withania somnifera (Ashwagandha) root extract and dietary l-ascorbic acid (vitamin C) at the rate of 1:1 (w/w). Fishes were fed for 60 days to find out the best dose and duration of feeding by examining different haematological (haemoglobin, haematocrit, total RBC count, total WBC count, MCV, MCH and MCHC), immunological (NBT, lysozyme and total immunoglobulin activity) and biochemical (glucose, total protein, ALP, SGPT and SGOT level) parameters on 7, 15, 30 and 60 days of feeding. The best response was observed in fish fed with diet T3 within 15 days. The result showed a significant (p < 0.05) increase in haemoglobin, haematocrit, total RBC count, total WBC count, NBT, lysozyme activity, total immunoglobulin and total protein whereas a significant (p < 0.05) decrease in glucose, ALP, SGPT and SGOT level compared to control. Challenged study against waterborne iron (6.02 mg l^-1) and low pH (4.2-4.5) after feeding the fish for 15 days with diet T3 showed significantly (P < 0.05) higher protection than control. The study concludes that inclusion of 1.0% Withania somnifera (Ashwagandha) root extract and dietary l-ascorbic acid (vitamin C) combination in diet have a stimulatory effect on immune response and reduces the effect of multiple stresses (i.e., low pH and waterborne iron toxicity) in L. rohita fingerlings.

Topical skin therapies in subjects undergoing full facial rejuvenation

BACKGROUND

Cosmeceutical therapies including face washes, moisturizers, chemical peels and antioxidant formulations are intended to improve the esthetic appearance of skin. The use of these products as adjuncts to full facial rejuvenation with hyaluronic acid filler and abobotulinumtoxinA may improve cosmetic and socio-esthetic outcomes.

OBJECTIVE

To characterize the effect of skin care products in subjects undergoing full facial rejuvenation with abobotulinumtoxinA and hyaluronic acid in improving facial skin appearance, patient satisfaction, and projected first impressions.

METHODS

Twenty subjects were recruited and divided into two treatment groups. Subjects in Group A followed a standard skin care regimen, whereas subjects in Group B received a more robust skin care regimen including chemical peels and antioxidant formulations. All subjects underwent facial rejuvenation treatments with hyaluronic acid at Visit 2 and with abobotulinumtoxinA at Visit 7. Patient esthetic improvement, satisfaction, self-esteem, and first impression were evaluated via the Fitzpatrick Wrinkle Assessment Scale, Global Aesthetic Improvement Scale, Skin Quality Assessment, Heatherton & Polivy State Self-Esteem Scale, Subject Satisfaction Scale, and the First Impressions Questionnaire.

RESULTS

Both treatment groups experienced significant improvements in the Skin Quality Assessment, Fitzpatrick Wrinkle Assessment Scale, Heatherton and Polivy State Self-Esteem Scale, and First Impressions Questionnaire.

CONCLUSION

The cosmeceutical therapies used in this study in combination with abobotulinumtoxinA and hyaluronic acid filler improved subjects' skin quality, self-esteem, and projected first impressions. Larger studies are needed to determine the most efficacious combination of topical skin therapies with facial rejuvenation therapy.

Biocompatible gadolinium oxide nanoparticles as efficient agent against pathogenic bacteria

The inappropriate and surfeit use of antibiotics have generated a hunt for safe and alternative antimicrobial agents against pathogenic bacteria. With the advancement in nanoscience and nanotechnology, promising opportunities for examining the bacterial effect of metal nanoparticles were demonstrated in literature. Focusing on this, our present study presentssynthesis of l-ascorbic coated gadolinium oxide nanoparticles via a simple precipitation route. Their complete characterization and detailed stability studies were carried out. The obtained nanoparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy, confirming that l-ascorbic acid onto the surface of nanoparticles. The size and morphology were analyzed by Transmission electron Microcopy (TEM) and Field emission scanning electron microscopy (FE-SEM) which reveals their spherical nature. The stability studies were performed to know about their chemical and colloidal stability. The synthesized nanoparticles were found to be non-toxic to HaCaT cells upto the concentration of 125 µg/mL. The antimicrobial effect of nanoparticles was analyzed against three bacterial strains; E. coli, S. aureus and S. typhimurium. To summarize, the synthesized nanoparticles are found to be safe and protective against pathogenic bacteria. They further can be explored in biomedical applications considering their non-toxic nature.

N,S,P Co-Doped Carbon Nanodot Fabricated from Waste Microorganism and Its Application for Label-Free Recognition of Manganese(VII) and l-Ascorbic Acid and AND Logic Gate Operation

A novel fluorescent probe based on N,S,P codoped carbon nanodots (N,S,P-CND_Sac) is very simple and quickly fabricated by a one-step hydrothermal pyrolysis of Saccharomyces cerevisiae and utilized for label-free and "on-off-on" sequential detection of manganese(VII) and l-ascorbic acid (l-AA). The fluorescence of N,S,P-CND_Sac can be effectively quenched by Mn(VII) based on an inner filter effect (IFE) and recovered upon the addition of l-AA due to the easy conversion of Mn(VII) to reduced states (i.e., Mn(IV), Mn(II), and Mn(0)) by l-AA. This probe exhibited favorable selectivity and sensitivity toward Mn(VII) and l-AA with detection limits of 50 nmol/L and 1.2 μmol/L, respectively. Simultaneously, an "AND" logic gate based on the as-fabricated N,S,P-CND_Sac has been constructed. Also, the as-proposed fluorescent probe was extended to detect Mn(VII) and l-AA in biosystems. Furthermore, the as-constructed fluorescent probe system was successfully applied to the analyses of Mn(VII) in tap water, Fenhe River water, and medicinal herb samples with satisfactory results. The proposed method is simple and easily accessible, demonstrating the great potential of N,S,P-CND_Sac in biosensing, disease diagnosis, cellular labeling, and environmental monitoring.

Valorizing Dairy Waste: Thermophilic Biosynthesis of a Novel Ascorbic Acid Derivative

l-Ascorbic acid (l-AA) is an essential nutrient that is extremely unstable and cannot be synthesized by the human body. Therefore, attempts have been performed to develop biologically active l-AA derivatives with improved stability. This work presents a facile, scalable, and efficient enzymatic transgalactosylation of lactose to l-AA using β-glucosidase (TN0602) from Thermotoga naphthophila RKU-10. β-Glucosidase TN0602 displays high transgalactosylation activity at pH 5.0, 75 °C, and l-AA/lactose ratio of 2:1 to form a novel l-AA derivative [2-O-β-d-galactopyranosyl-l-ascorbic acid (l-AA-Gal)] with a maximal productivity of 138.88 mmol L^-1 in 12 h, which is higher than most reports of enzymatic synthesis of l-AA-α-glucoside. Synthetic l-AA-Gal retains most l-AA antioxidant capability and presents dramatically higher stability than l-AA in an oxidative environment (Cu²⁺). In conclusion, this work reports a new way to valorize dairy waste lactose into a novel molecule l-AA-Gal, which could be a promising l-AA derivative to be used in a wide range of applications.

Preservation of orange juice using propolis

Orange juice is one of the most popular and the most consumed fruit juices all over the world, especially in Europe and the chemical food preservatives, such as sodium benzoate, potassium sorbate and their mixtures, have long been used in orange juice sold on the market. Excessive consumption of these preservatives may be hazardous to human health. Propolis, composed of resins collected from plant buds and exudates and mixed with salivary gland secretions and beeswax by honey bee workers, has been used as a human medicine and natural food preservative. We hypothesis that propolis, without alcohol, can serve as an alternative and non-synthetic preservative of orange juice. In this study, the preservative effect of propolis emulsion on orange juice was determined up to 35 days. Propolis emulsion (0.02 g/mL propolis, 12 mL), emulsion control (12 mL containing Tween-80, hydrophilic phospholipid and polyethylene glycol 400), sodium benzoate (0.4 g) and potassium sorbate (0.4 g) was each added to 388, 388, 400 and 400 mL orange juice respectively. Propolis emulsion showed significant inhibition of bacteria growth and l-ascorbic acid degradation. Orange juice pH value, titratable acidity, total phenolic content, color and antioxidant capacity were effectively maintained by propolis emulsion. A control solution with all the same emulsifying agents without propolis did not show these properties. It was concluded that propolis can be used as a natural additive agent in orange juice or other fruit juices as an alternative to chemical preservatives.

Ascorbate pool, sugars and organic acids in black currant (Ribes nigrum L.) berries are strongly influenced by genotype and post-flowering temperature

BACKGROUND

Marked effects of the climatic environment on fruit chemical composition have often been demonstrated in field experiments. However, complex covariations of several climatic factors in the natural environment complicate the interpretation of such experiments and the identification of the causal factors. This can be better achieved in a phytotron where the various climatic factors can be varied systematically. Therefore, we grew four black currant cultivars of contrasting origin in a phytotron under controlled post-flowering temperature and photoperiod conditions and analysed the berries for their ascorbic acid, sugar and organic acid contents.

RESULTS

The analyses revealed significant effects of genotype on all investigated compounds. Particularly large cultivar differences were observed in the concentrations of l-ascorbic acid (AA) and sucrose. The concentrations of both AA and dehydroascorbic acid (DHAA), as well as the concentrations of all major sugars, decreased consistently with an increasing temperature over the temperature range 12-24 °C. Fructose and glucose were the predominant sugars with concentrations several fold higher than that for sucrose. AA was the main contributor to the total ascorbate pool in black currant berries. The AA/DHAA ratio varied from 5.6 to 10.3 among the studied cultivars. The concentration of citric acid, which was the predominant organic acid in black currant berries, increased with an increasing temperature, whereas the opposite trend was observed for malic and shikimic acid. Quninic acid was always present at relatively low concentrations. By contrast, photoperiod had no significant effect on berry content of any of the investigated compounds.

CONCLUSION

It is concluded that the post-flowering temperature has marked effects on the concentration of important chemical compounds responsible for taste and nutritional value of black currant berries, whereas photoperiod has no such effect in the studied cultivars. © 2016 Society of Chemical Industry.

Active antioxidants in ex-vivo examination of burn wound healing by means of IR and Raman spectroscopies-Preliminary comparative research

Being a complex traumatic event, burn injury also affects other organ systems apart from the skin. Wounds undergo various pathological changes which are accompanied by alterations in the molecular environment. Information about molecules may be obtained with the use of Raman spectroscopy and Fourier-transform infrared spectroscopy, and when combined, both methods are a powerful tool for providing material characterization. Alterations in the molecular environment may lead to identifying objective markers of acute wound healing. In general, incubation of samples in solutions of l-ascorbic acid and 5% and 7% orthosilicic acid organizes the collagen structure, whereas the increased intensity of the Raman bands in the region of 1500-800cm^-1 reveals regeneration of the burn tissue. Since oxidative damage is one of the mechanisms responsible for local and distant pathophysiological events after burn, antioxidant therapy can prove to be beneficial in minimizing burn wounds, which was examined on the basis of human skin samples and chicken skin samples, the latter being subject to modification when heated to a temperature sufficient for the simulation of a burn incident.

Roasting Enhances the Anti-Cataract Effect of Coffee Beans: Ameliorating Selenite-Induced Cataracts in Rats

PURPOSE

Coffee is a widely consumed beverage. While recent studies have linked its intake to a reduced risk of cataracts, caffeine is believed to be the key factor for its effect. To know how roasting beans affects the effect of coffee on cataract formation, we investigated the impact roasting using a selenite-induced cataract rat model.

MATERIALS AND METHODS

Sprague Dawley rats were given a single injection of sodium selenite, which induced formation of nuclear cataracts by day 6, with or without coffee intake (100% coffee, 0.2 mL/day) for following 3 days.

RESULTS

The concentrations of glutathione (GSH) and ascorbic acid (AsA) in selenite-induced cataract lenses declined to half that of controls. However, 3 days of coffee intake ameliorated the reduction of GSH and AsA so that concentrations remained at 70-80% that of controls. Roasting enhanced the preventive effect of coffee by further reducing cataract formation and ameliorating selenite-induced reduction of antioxidants. High-performance liquid chromatography analysis revealed degradation of chlorogenic acid and generation of pyrocatechol during the coffee roasting process. We discovered that pyrocatechol, at doses equivalent to that found in dark-roasted coffee, was equally effective as caffeine at reducing cataract formation and ameliorating the reduction of antioxidants.

CONCLUSION

Our results indicate that pyrocatechol, generated during the roasting process, acts as an antioxidant together with caffeine to prevent cataract formation.

Exploring hazards of acute exposure of Acephate in Drosophila melanogaster and search for l-ascorbic acid mediated defense in it

This study reveals protective role of l-ascorbic acid (25, 50 and 100μg/mL) against toxic impacts of acute sub-lethal exposure of Acephate (5μg/mL) in a non-target organism Drosophila melanogaster. Organismal effect was evident from increased impairment in climbing activities (9 folds) of treated individuals who also manifested altered ocular architecture. These anomalies were reduced with l-ascorbic acid (l-AA) supplementation. Acephate induced apoptotic lesions in eye imaginal discs and gut confirmed tissue damage that also reduced with l-AA co-treatment. Reduction in viability of fat body cells (∼41%), neural cells (∼42%) and hemocytes (3 folds) indicates cytotoxic and immunotoxic potential of Acephate, which were significantly mitigated with l-AA co-administration. The sub-cellular toxic impacts of Acephate treatment became obvious from enhancement in activities of antioxidant enzymes (CAT by ∼1.63 folds, SOD by ∼1.32 folds), detoxifying enzymes (Cyp450 by ∼1.99 folds and GST by ∼1.34 folds), 2.1 times boost in HSP 70 expression, and inhibition of cholinesterase activity (by ∼0.66 folds). DNA breaks evident through comet assay confirmed Acephate triggered genotoxicity which could also be prevented through co-administration of. L-AA Furthermore, the study proposes the use of Drosophila as a model to screen chemicals for their protective potential against pesticide toxicity.

Effect of ultrasound and heat on percutaneous absorption of l-ascorbic acid: human in vitro studies on Franz cell and Petri dish systems

OBJECTIVE

Percutaneous absorption of l-ascorbic acid (LAA) is limited due to its high hydrophilicity and low stability. Here, we investigated the effect of post-dosing sonophoresis (329 kHz, 20 mW cm^-2 ) and heat (36°C) on transdermal delivery of LAA.

METHODS

Ultrasound/heat, heat and control treatments were applied on skin surface for 2 and 5 min after topical application of C14-labelled LAA aqueous solution. After 15 min post-exposure, radioactivity was measured in tape-striped stratum corneum (TS-SC), epidermis, dermis and receptor fluid. As Franz diffusion cell model may have different acoustic response than in vivo human tissues, a novel Petri dish model was developed and compared with Franz cell model on the effects of ultrasound/heat treatment on the skin permeability.

RESULTS

Five-min ultrasound/heat treatment significantly accelerated skin absorption/penetration of LAA; 2-min treatment showed no enhancement effect on Franz diffusion cell model at the end of experiment. The use of Petri dish model significantly increased LAA concentrations in epidermis after 5 min of ultrasound/heat treatment, compared to the results of Franz cell model.

CONCLUSION

Combination of ultrasound (329 kHz, 20 mW cm^-2 ) and heat (36°C) significantly enhanced LAA transdermal penetration, when the time of treatment was sufficient (5 min). As Petri dish model was designed to simulate acoustic respond of dense human tissue to ultrasound, the difference between Franz cell and Petri dish models suggests that the enhancement effect of ultrasound/heat on skin penetration in vivo may be greater than that determined on in vitro Franz cell model.

Determination of the optimum mixture of transglutaminase, l-ascorbic acid and xylanase for the quality and consumer acceptability of bread using response surface methodology

The optimum levels of transglutaminase (TGase), l-ascorbic acid (l-AA), and xylanase (Xyl) were determined using response surface methodology to improve quality and consumer acceptability of bread made with wheat flour. A Box-Behnken design with three independent variables (TGase, l-AA, and Xyl) and three levels was used to develop models for the different responses (peak time, mixing tolerance, extensibility, resistance, specific volume, hardness, and consumer acceptability). Overall, l-AA and Xyl improved dough and bread properties, whereas the addition of TGase positively affected to texture and overall acceptability by consumer test. The optimal formulation for dough and bread properties and consumer acceptability were identified and the optimal value was 0.36 g/100 g TGase, 0.026 g/100 g Xyl, and 0.005 g/100 g l-AA. The results demonstrate that the addition of optimum amounts of TGase, Xyl, and l-AA improves the baking quality of the flour by enhancing dough properties and increase the consumer acceptability of the bread.

Volumetric and UV absorption studies on understanding the solvation behavior of polyhydroxy solutes in l-ascorbic acid(aq) solutions at T=(288.15 to 318.15)K

Thermodynamic and spectroscopic data characterizing the solvation behavior of polyhydroxy compounds are in demand to get better understanding about the mechanisms of taste chemoreception, protein stabilization, etc. Apparent molar volumes for monosaccharides, disaccharides, derivatives, and polyols in (0.05, 0.15, 0.25 and 0.35) mol kg(-1) aqueous solutions of l-ascorbic acid have been determined from density data measured at (288.15, 298.15, 308.15 and 318.15)K under atmospheric pressure. Standard partial molar volumes at infinite-dilution and corresponding volumes of transfer of solutes from water to L-ascorbic acid(aq) have been calculated. Interaction coefficients and standard partial molar expansibilities have also been evaluated. The basic taste quality of studied solutes has been assessed from apparent massic volumes. UV absorption studies support the interactions between solutes and L-ascorbic acid. Influence of pH variation was taken into consideration while evaluating chemical behavior and stability of L-ascorbic acid in aqueous and buffer solutions.

Ascorbate Oxidase-Based Amperometric Biosensor for l-Ascorbic Acid Determination in Beverages

A novel biosensor for l-ascorbic acid determination in different beverages was elaborated. The ascorbate oxidase enzyme (AAO) from Cucurbita sp., EC 1.10.3.3, was immobilized on a screen-printed carbon electrode with poly(ethylene glycol) (400) diglycidyl ether (PEGDGE) as a crosslinking agent. The standards and samples were measured first with a blank electrode. An inert protein, bovine serum albumin (BSA), was immobilized on the surface of this electrode with PEGDGE. The BSA mass was equivalent to the mass of 10 U of AAO enzyme immobilized on the electrodes (0.021 mg). The linear measuring range for l-ascorbic acid was between 5 and 150 µmol/L. As l-ascorbic acid is a vital vitamin and a common antioxidant used in food industry, fruit juices and vitamin C effervescent tablets were examined. The results were compared to HPLC measurements.

Identification and characterization of Arabidopsis AtNUDX9 as a GDP-d-mannose pyrophosphohydrolase: its involvement in root growth inhibition in response to ammonium

GDP-d-mannose (GDP-d-Man) is an important intermediate in ascorbic acid (AsA) synthesis, cell wall synthesis, protein N-glycosylation, and glycosylphosphatidylinositol-anchoring in plants. Thus, the modulation of intracellular levels of GDP-d-Man could be important for maintaining various cellular processes. Here an Arabidopsis GDP-d-Man pyrophosphohydrolase, AtNUDX9 (AtNUDT9; At3g46200), which hydrolysed GDP-d-Man to GMP and mannose 1-phosphate, was identified. The K m and V max values for GDP-d-Man of AtNUDX9 were 376±24 μM and 1.61±0.15 μmol min(-1) mg(-1) protein, respectively. Among various tissues, the expression levels of AtNUDX9 and the total activity of GDP-d-Man pyrophosphohydrolase were the highest in the roots. The GDP-d-Man pyrophosphohydrolase activity was increased in the root of plants grown in the presence of ammonium. No difference was observed in the levels of AsA in the leaf and root tissues of the wild-type and knockout-nudx9 (KO-nudx9) plants, whereas a marked increase in N-glycoprotein levels and enhanced growth were detected in the roots of KO-nudx9 plants in the presence of ammonium. These results suggest that AtNUDX9 is involved in the regulation of GDP-d-Man levels affecting ammonium sensitivity via modulation of protein N-glycosylation in the roots.

Environmental effect of antioxidant additives on exhaust emission reduction in compression ignition engine fuelled with Annona methyl ester

The aim of the present study is to analyse the effect of antioxidant l-ascorbic acid on engine performance and emissions of a diesel engine fuelled with methyl ester of Annona oil (MEAO). The antioxidant is mixed in various concentrations (100-400 mg) with MEAO. Result shows that the antioxidant additive mixture (MEAO+LA200) is effective in control of nitrogen oxides (NOx) and hydrocarbon (HC) emission of MEAO-fuelled engine without doing any engine modification. In this study by using MEAO, the NOx emission is reduced by about 23.38% at full load while compared with neat diesel fuel. Likewise there is a reduction in carbon monoxide, smoke, and HC by about 48%, 28.57% and 29.71% at full load condition compared with neat diesel fuel.

Influence of the complex of retinol-vitamin C on skin surface lipids

BACKGROUND

Retinol is used to reduce symptoms of skin aging. It affects surface lipids and increases skin regeneration ability.

AIM

The aim of our study was to investigate the effect of retinol peel on the face and neck skin lipids in women, aged 50-69.

MATERIAL AND METHODS

The level of secreted sebum was measured using Sebumeter SM15 (Courage & Khazaka, Germany) on the forehead, cheeks, nose, chin, and neck. The measurements were carried out before each of the 3 retinol peel treatments applied at 3-week interval and 3 weeks after the last treatment.

RESULTS

A statistically significant increase of lipid film in both U-zone and T-zone and on the neck was observed in the study group.

CONCLUSION

Retinol peel treatments can help to increase the amount of skin surface lipids in women during menopause.

Variation in the SLC23A1 gene does not influence cardiometabolic outcomes to the extent expected given its association with L-ascorbic acid

BACKGROUND

Observational studies showed that circulating L-ascorbic acid (vitamin C) is inversely associated with cardiometabolic traits. However, these studies were susceptible to confounding and reverse causation.

OBJECTIVES

We assessed the relation between L-ascorbic acid and 10 cardiometabolic traits by using a single nucleotide polymorphism in the solute carrier family 23 member 1 (SLC23A1) gene (rs33972313) associated with circulating L-ascorbic acid concentrations. The observed association between rs33972313 and cardiometabolic outcomes was compared with that expected given the rs33972313-L-ascorbic acid and L-ascorbic acid-outcome associations.

DESIGN

A meta-analysis was performed in the following 5 independent studies: the British Women's Heart and Health Study (n = 1833), the MIDSPAN study (n = 1138), the Ten Towns study (n = 1324), the British Regional Heart Study (n = 2521), and the European Prospective Investigation into Cancer (n = 3737).

RESULTS

With the use of a meta-analysis of observational estimates, inverse associations were shown between L-ascorbic acid and systolic blood pressure, triglycerides, and the waist-hip ratio [the strongest of which was the waist-hip ratio (-0.13-SD change; 95% CI: -0.20-, -0.07-SD change; P = 0.0001) per SD increase in L-ascorbic acid], and a positive association was shown with high-density lipoprotein (HDL) cholesterol. The variation at rs33972313 was associated with a 0.18-SD (95% CI: 0.10-, 0.25-SD; P = 3.34 × 10⁻⁶) increase in L-ascorbic acid per effect allele. There was no evidence of a relation between the variation at rs33972313 and any cardiometabolic outcome. Although observed estimates were not statistically different from expected associations between rs33972313 and cardiometabolic outcomes, estimates for low-density lipoprotein cholesterol, HDL cholesterol, triglycerides, glucose, and body mass index were in the opposite direction to those expected.

CONCLUSIONS

The nature of the genetic association exploited in this study led to limited statistical application, but despite this, when all cardiometabolic traits were assessed, there was no evidence of any trend supporting a protective role of L-ascorbic acid. In the context of existing work, these results add to the suggestion that observational relations between L-ascorbic acid and cardiometabolic health may be attributable to confounding and reverse causation.

Preparation, transportation mechanisms and brain-targeting evaluation in vivo of a chemical delivery system exploiting the blood-cerebrospinal fluid barrier

In recent years, specific transportation mechanisms on the blood-brain barrier (BBB) are extensively employed for brain-targeted drug delivery via colloidal nanocarriers. However, in this study, we purposed to exploit the sodium-dependent vitamin C transporter 2 (SVCT2)-mediated transportation on the blood-cerebrospinal fluid barrier to enhance central nervous system penetration of the highly hydrophilic ibuprofen (IBU) by synthesizing a SVCT2-targeted chemical delivery system (CDS), ibuprofen-C6-O-ascorbic acid (IAA). The physicochemical parameters of IAA were determined, and the transporter-mediated transportation mechanism of IAA was explored on a BBB monolayer mode. The overall brain targeting effect of IAA was assayed on mice by measuring the biodistribution of IBU after i.v. administration and calculating the pharmacokinetic parameters and targeting indexes. Results showed that lipophilicity and solubility of IAA was conspicuously improved compared with IBU. At the physiological pH, IAA was stable while in brain homogenates it was easily degraded. Transport studies on the BBB monolayer mode revealed that IAA displayed higher transepithelial permeability than IBU via SVCT2. The biodistribution study in vivo demonstrated that the overall targeting efficiency of IAA was 1.77-fold greater than that of the IBU. In conclusion, the synthetic IAA might be a promising brain-targeted CDS for smuggling small-molecule hydrophilic pharmaceuticals into the brain.

Localized infusions of the partial alpha 7 nicotinic receptor agonist SSR180711 evoke rapid and transient increases in prefrontal glutamate release

The ability of local infusions of the alpha 7 nicotinic acetycholine receptor (α7 nAChR) partial agonist SSR180711 to evoke glutamate release in prefrontal cortex was determined in awake rats using a microelectrode array. Infusions of SSR180711 produced dose-dependent increases in glutamate levels. The lower dose (1.0μg in 0.4μL) evoked a rapid rise (∼1.0s) in glutamate (1.41±0.30μM above baseline). The higher dose (5.0μg) produced a similarly rapid, yet larger increase (3.51±0.36μM above baseline). After each dose, the glutamate signal was cleared to basal levels within 7-18s. SSR180711-evoked glutamate was mediated by the α7 nAChR as co-infusion of the selective α7 nAChR antagonist α-bungarotoxin (10.0μM)+SSR1808711 (5.0μg) reduced the effect of 5.0μg alone by 87% (2.62 vs. 0.35μM). Finally, the clearance of the SSR180711 (5.0μg)-evoked glutamate was bidirectionally affected by drugs that inhibited (threo-beta-benzyl-oxy-aspartate (TβOA), 100.0μM) or facilitated (ceftriaxalone, 200mg/kg, i.p.) excitatory amino acid transporters. TβOA slowed both the clearance (s) and rate of clearance (μM/s) by 10-fold, particularly at the mid-late stages of the return to baseline. Ceftriaxone reduced the magnitude of the SSR180711-evoked increase by 65%. These results demonstrate that pharmacological stimulation of α7 nAChRs within the prefrontal cortex is sufficient to evoke rapid yet transient increases in glutamate levels. Such increases may underlie the cognition-enhancing effects of the drug in animals; further justifying studies on the use of α7 nAChR-positive modulators in treating cognition-impairing disorders in humans.

Metabolic engineering of Kluyveromyces lactis for L-ascorbic acid (vitamin C) biosynthesis

BACKGROUND

L-ascorbic acid (L-AA) is naturally synthesized in plants from D-glucose by 10 steps pathway. The pathway branch to synthesize L-galactose, the key intermediate for L-ascorbic acid biosynthesis, has been recently elucidated. Budding yeast produces an 5-carbon ascorbic acid analogue Dehydro-D-arabinono 1,4-lactone (D-DAL), which is synthesized from D-arabinose. Yeast is able to synthesize L-ascorbic acid only if it is cultivated in the presence of one of its precursors: L-galactose, L-galactono 1,4-lactone, or L-gulono 1,4-lactone extracted from plants or animals. To avoid feeding the yeast culture with this "L" enantiomer, we engineered Kluyveromyces lactis with L-galactose biosynthesis pathway genes: GDP-mannose 3,5-epimerase (GME), GDP-L-galactose phosphorylase (VTC2) and L-galactose-1-phosphate phosphatase (VTC4) isolated from Arabidopsis thaliana.

RESULTS

Plasmids were constructed and modified such that the cloned plant genes were targeted to the K. lactis LAC4 Locus by homologous recombination and that the expression was associated to the growth on D-galactose or lactose. Upon K. lactis transformation, GME was under the control of the native LAC4 promoter whereas VTC2 and VTC4 were expressed from the S. cerevisiae promoters GPD1 and ADH1 respectively. The expression in K. lactis, of the L-galactose biosynthesis genes was determined by Reverse Transcriptase-PCR and western blotting. The recombinant yeasts were capable to produce about 30 mg.L(-1) of L-ascorbic acid in 48 hours of cultivation when cultured on rich medium with 2% (w/v) D-galactose. We also evaluated the L-AA production culturing recombinant recombinant strains in cheese whey, a waste product during cheese production, as an alternative source of lactose.

CONCLUSIONS

This work is the first attempt to engineer K. lactis cells for L-ascorbic acid biosynthesis by a fermentation process without any trace of "L" isomers precursors in the culture medium. We have engineered K. lactis strains capable of converting lactose and D-galactose into L-galactose, by the integration of the genes from the A. thaliana L-galactose pathway. L-galactose is a rare sugar, which is one of the main precursors for L-AA production.

Indigenous plasmids of Bacillus megaterium WSH-002 involved in mutualism with Ketogulonicigenium vulgare WSH-001

In the two-step vitamin C fermentation process, the precursor 2-keto-l-gulonic acid (2-KLG) was synthesized using a mixed culture of Ketogulonicigenium vulgare WSH-001 and Bacillus megaterium WSH-002, which contained three plasmids, pBME1, pBME2 and pBME3. The cell growth of B. megaterium was not affected by the elimination of these plasmids. However, elimination of pBME2 and pBME3 significantly affected l-sorbose uptake and 2-KLG production. Sequence analysis of the plasmids showed that many of the pBME2 and pBME3 genes were of unknown function or could not be assigned to a specific metabolic pathway. The current work showed that the indigenous plasmids pBME2 and pBME3 of B. megaterium WSH-002 involved in mutualism with K. vulgare WSH-001. The results provided a promising new route to further demonstrate the mutualism process between the two bacteria.

Disentangling the Puzzle of Hydrogen Bonding in Vitamin C

Fast-passage Fourier transform microwave spectroscopy in combination with a laser ablation source has been successfully applied to probe vitamin C (l-ascorbic acid) in the gas phase. Its ethyldiol side chain and two hydroxyl groups around the γ-lactone ring provide five internal rotation axes, enabling vitamin C to assume a wide variety of nonplanar 3D cooperative hydrogen bond networks that can also include the keto and ether functions. The rotational constants extracted from the analysis of the spectrum unequivocally identify the existence of three dominant conformers stabilized by different intramolecular hydrogen bonding motifs forming five-, six-, or seven-membered rings.

Genetic variation at the SLC23A1 locus is associated with circulating concentrations of L-ascorbic acid (vitamin C): evidence from 5 independent studies with >15,000 participants

BACKGROUND

L-ascorbic acid is an essential part of the human diet and has been associated with a wide range of chronic complex diseases, including cardiovascular outcomes. To date, there are no confirmed genetic correlates of circulating concentrations of L-ascorbic acid.

OBJECTIVE

We aimed to confirm the existence of an association between common variation at the SLC23A1 gene locus and circulating concentrations of L-ascorbic acid.

DESIGN

We used a 2-stage design, which included a discovery cohort (the British Women's Heart and Health Study), a series of follow-up cohorts, and meta-analysis (totaling 15,087 participants) to assess the relation between variation at SLC23A1 and circulating concentrations of L-ascorbic acid.

RESULTS

In the discovery cohort, variation at rs33972313 was associated with a reduction in circulating concentrations of L-ascorbic acid (-4.15 micromol/L; 95% CI: -0.49, -7.81 micromol/L; P = 0.03 reduction per minor allele). Pooled analysis of the relation between rs33972313 and circulating L-ascorbic acid across all studies confirmed this and showed that each additional rare allele was associated with a reduction in circulating concentrations of L-ascorbic acid of -5.98 micromol/L (95% CI: -8.23, -3.73 micromol/L; P = 2.0 x 10(-7) per minor allele).

CONCLUSIONS

A genetic variant (rs33972313) in the SLC23A1 vitamin C active transporter locus was identified that is reliably associated with circulating concentrations of L-ascorbic acid in the general population. This finding has implications more generally for the epidemiologic investigation of relations between circulating L-ascorbic acid and health outcomes.

Protective effect of L-ascorbic acid against oxidative damage in the liver of rats with water-immersion restraint stress

We examined whether L-ascorbic acid (AA) (or reduced ascorbic acid) protects against oxidative damage in the liver of rats subjected to water-immersion stress (WIRS). AA (100, 250 or 500 mg/kg) was orally administered at 0.5 h before the onset of WIRS. Rats with 6 h of WIRS had increased serum corticosterone, glucose, total ascorbic acid (T-AA), AA, lipid peroxide (LPO), and NOx concentrations and alanine aminotransferase and aspartate aminotrasferase activities. The stressed rats had increased hepatic LPO, NOx, and dehydroascorbic acid concentrations and myeloperoxidase activity, decreased hepatic T-AA, AA, reduced glutathione concentrations and superoxide dismutase activity, and unchanged hepatic vitamin E concentration. Pre-administered AA attenuated the stress-induced changes in serum LPO and NOx concentrations and alanine aminotransferase and aspartate aminotrasferase activities and hepatic LPO, NOx, and T-AA, AA, dehydroascorbic acid, and reduced glutathione concentrations and myeloperoxidase and superoxide dismutase activities dose-dependently. Pre-administered AA did not affect the stress-induced changes in serum corticosterone and glucose concentrations. These results indicate that pre-administered AA protects against oxidative damage in the liver of rats with WIRS possibly by attenuating disruption of the antioxidant defense system and increases in NO generation and neutrophil infiltration in the tissue.

GDP-mannose pyrophosphorylase is a genetic determinant of ammonium sensitivity in Arabidopsis thaliana

Higher plant species differ widely in their growth responses to ammonium (NH(4)(+)). However, the molecular genetic mechanisms underlying NH(4)(+) sensitivity in plants remain unknown. Here, we report that mutations in the Arabidopsis gene encoding GDP-mannose pyrophosphorylase (GMPase) essential for synthesizing GDP-mannose confer hypersensitivity to NH(4)(+). The in planta activities of WT and mutant GMPases all were inhibited by NH(4)(+), but the magnitude of the inhibition was significantly larger in the mutant. Despite the involvement of GDP-mannose in both l-ascorbic acid (AsA) and N-glycoprotein biosynthesis, defective protein glycosylation in the roots, rather than decreased AsA content, was linked to the hypersensitivity of GMPase mutants to NH(4)(+). We conclude that NH(4)(+) inhibits GMPase activity and that the level of GMPase activity regulates Arabidopsis sensitivity to NH(4)(+). Further analysis showed that defective N-glycosylation of proteins, unfolded protein response, and cell death in the roots are likely important downstream molecular events involved in the growth inhibition of Arabidopsis by NH(4)(+).