Search Results (158)

Ascorbic acid (AA) plays a multidimensional role in human physiological and pathological processes, and the detection of its urinary concentration facilitates the diagnosis of metabolic or kidney diseases. Visual detection exhibits minimal reliance on instrumentation and is suitable for on-site analysis in routine settings. Current visual colorimetric detection methods typically rely on enzymatic or nanozyme-based catalysis. Organic neutral radicals bearing unpaired electrons represent a class of materials exhibiting intrinsic responsiveness to redox stimuli. The tris (2,4,6-trichlorophenyl) methyl (TTM) radical has attracted widespread attention for its adjustable optical properties and sensitive response to external redox stimuli. We synthesized a novel radical TTM-DMODPA and applied it for non-catalytic colorimetric detection of AA. It not only enables quantitative AA measurement via UV-vis spectroscopy (linear range: 1.25–75 μmol/L, LOD: 0.288 μmol/L) but also facilitates instrument-free visual detection using smartphone cameras (linear range: 0–65 μmol/L, LOD: 1.46 μmol/L). This method demonstrated satisfactory performance in the measurement of AA in actual urine samples. Recovery rates ranged from 97.8% to 104.1%. Consequently, this work provides a portable and effective method for assessing AA levels in actual urine samples. Full article

Lithium-ion batteries (LiBs) are utilized in numerous applications due to advancements in technology, and the recovery of end-of-life (EoL) LiBs is imperative for environmental and economic reasons. Pyrometallurgical and hydrometallurgical methods have been used in the recovery of metals such as Li, Co, and Ni in the EoL LiBs. Hydrometallurgical methods, which have been demonstrated to exhibit higher recovery efficiency and reduced energy consumption, have garnered increased attention in recent research. Inorganic acids, including HCl, HNO₃, and H₂SO₄, as well as organic acids such as acetic acid and citric acid, are employed in the hydrometallurgical recovery of these metals. It is imperative to acknowledge the environmental hazards posed by these acids. Consequently, solvometallurgical processes, which involve the use of organic solvents with minimal or no water, are gaining increasing attention as alternative or complementary techniques to conventional hydrometallurgical processes. In the context of solvent systems that have been examined for a range of solvometallurgical methods, deep eutectic solvents (DESs) have garnered particular interest due to their low toxicity, biodegradable nature, tunable properties, and efficient metal recovery potential. In this study, the leaching process of black mass containing graphite, LCO, NMC, and LMO was carried out in a short time using the ternary DES system. The ternary DES system consists of choline chloride (ChCl), glycolic acid (GLY), and ascorbic acid (AA). As a result of the leaching process of cathode powders in the black mass without any pre-enrichment process, Li, Co, Ni, and Mn elements passed into solution with an efficiency of over 95% at 60 °C and within 1 h. Moreover, the kinetics of the leaching process was investigated, and Density Functional Theory (DFT) calculations were used to explain the leaching mechanism. Full article

Tissue engineering enables autologous reconstruction of human tissues, addressing limitations in tissue availability and immune compatibility. Several tissue engineering techniques, such as self-assembly, rely on or benefit from extracellular matrix (ECM) secretion by fibroblasts to produce biomimetic scaffolds. Models have been developed for use in humans, such as skin and corneas. Ascorbic acid (vitamin C, AA) is essential for collagen biosynthesis. However, AA is chemically unstable in culture, with a half-life of 24 h, requiring freshly prepared AA with each change of medium. This study aims to demonstrate the functional equivalence of 2-phospho-L-ascorbate (2PAA), a stable form of AA, for tissue reconstruction. Dermal, vaginal, and bladder stroma were reconstructed by self-assembly using tissue-specific protocols. The tissues were cultured in a medium supplemented with either freshly prepared or frozen AA, or with 2PAA. Biochemical analyses were performed on the tissues to evaluate cell density and tissue composition, including collagen secretion and deposition. Histology and quantitative polarized light microscopy were used to evaluate tissue architecture, and mechanical evaluation was performed both by tensiometry and atomic force microscopy (AFM) to evaluate its macroscopic and cell-scale mechanical properties. The tissues produced by the three ascorbate conditions had similar collagen deposition, architecture, and mechanical properties in each organ-specific stroma. Mechanical characterization revealed tissue-specific differences, with tensile modulus values ranging from 1–5 MPa and AFM-derived apparent stiffness in the 1–2 kPa range, reflecting the nonlinear and scale-dependent behavior of the engineered stroma. The results demonstrate the possibility of substituting AA with 2PAA for tissue engineering. This protocol could significantly reduce the costs associated with tissue production by reducing preparation time and use of materials. This is a crucial factor for any scale-up activity. Full article

Vitamin C, also known as L-ascorbic acid (AA), functions as a pro-oxidant in cancer at high doses and exerts anticancer effects by generating reactive oxygen species (ROS) and selectively inducing damage to cancer cells. However, AA at low doses promotes cancer cell proliferation. The efficacy of high-dose AA therapy is frequently restricted by inadequate intracellular AA uptake, resulting from low expression of sodium-dependent vitamin C transporter 2 (SVCT2). In this study, we investigated whether valproic acid (VPA), a histone deacetylase inhibitor, could circumvent this constraint by increasing the expression of SVCT2 in colorectal cancer cells, including HCT-116 and DLD-1 with low SVCT2 levels. We found that VPA increased SVCT2 expression in both cell lines. Co-treatment with AA and VPA increased the number of apoptotic cells and enhanced intracellular AA uptake via VPA-upregulated SVCT2, followed by increased ROS production in both cell lines. Furthermore, the combination increased the synergistic anticancer effects and suppressed the hormetic dose response of AA in both cell lines. In a xenograft mouse model, co-treatment decreased tumor size and increased the tumor growth inhibition ratio compared to treatment with AA or VPA alone. Accordingly, VPA treatment enhanced SVCT2 expression in colorectal cancer cells, suppressed the hormetic dose-response effect of AA, and improved the potential of high-dose AA therapy as an anticancer agent. Full article

Malania oleifera Chun & S.K. Lee, an endemic monotypic species that belongs to the family Olacaceae, is under continuous pressure of decline owing to several ecological and physiological factors. The present study aimed to establish an efficient in vitro protocol for callus-mediated indirect somatic embryogenesis in M. oleifera by alleviating tissue browning. Internodes and leaves obtained from seedlings were used as explants. Antioxidant pre-treatment (ascorbic acid, AA) followed by different carbon sources (sucrose, maltose, glucose, and fructose) and plant growth regulators in various concentrations and combinations were employed in Woody Plant Medium (WPM) to alleviate explant browning and induce callus formation from the explants. AA pre-treatment and subsequent culture on maltose at a concentration of 116.8 mM were optimal for controlling phenolic exudation on >90% of both explants. The highest responses of 53.77% and 57.43% for embryogenic calli were induced from internode and leaf explants, respectively. The highest responses, 85.22% and 93.80%, were observed for somatic embryos that matured into the globular, heart-shaped and torpedo stages at different percentages on NAA 2.5 mg/L in combination with BA 1.0 mg/L for both explants. The matured somatic embryos were finally germinated at a maximum concentration of GA₃, 2.0 mg/L. All plantlets were successfully hardened and acclimatized under culture room conditions and then transferred to the greenhouse. The current study suggests an efficient protocol for indirect somatic embryogenesis by alleviating phenolic exudation from the explants of M. oleifera. This first successful report of in vitro culture establishment in M. oleifera may offer an effective alternative measure to conserve this species and provide a system for analyzing bioactive chemicals and for use in the oil industry. Full article

Tungsten-doped vanadium dioxide (W-VO₂) shows semiconductor-to-metal phase transition properties at room temperature, which is an ideal thermo-chromic smart window material. However, low visual transmittance and solar modulation limit its application in building energy saving. In this paper, a W-VO_2−x@AA core-shell nanoparticle is proposed to improve the thermo-chromic performance of W-VO₂. Oxygen vacancies were used to promote the connection of W-VO_2−x nanoparticles with L-ascorbic acid (AA) molecules. Oxygen vacancies were tuned in W-VO₂ nanoparticles by thermal annealing temperatures in vacuum, and W-VO_2−x@AA nanoparticles were synthesized by the hydrothermal method. A smart window was formed by dispersing W-VO_2−x@AA core-shell nanoparticles into PVP evenly and spin-coating them on the surface of glass. The visual transmittance of this smart window reaches up to 67%, and the solar modulation reaches up to 12.1%. This enhanced thermo-chromic performance is related to the electron density enhanced by the AA surface molecular coordination effect through W dopant and oxygen vacancies. This work provides a new strategy to enhance the thermo-chromic performance of W-VO₂ and its application in the building energy-saving field. Full article

Local anesthetics (LAs) are frequently administered via peritendinous ultrasound-guided injections for diagnostic and therapeutic purposes. Since in vitro studies have demonstrated LAs’ tenotoxic effects, raising concerns about their safety in infiltrative treatments, and since lidocaine (LD) emerged as one of the most cytotoxic LAs, we analyzed apoptosis, oxidative stress, and collagen turnover pathways in human tenocytes treated with LD, as well as the possible protection from LD-induced injury elicited by antioxidant ascorbic acid (AA). Tenocytes from gluteal tendons were treated with 0.2 and 1 mg/mL LD, or left untreated (CT), and treated with 50 μg/mL or 250 μg/mL AA. Nuclear morphology, cytochrome c expression, and caspase 3 activation were analyzed to study the effect of LD on apoptosis. Heme Oxygenase 1 (HO-1) mRNA and genes and proteins involved in collagen turnover were investigated using molecular approaches. Our results show that 0.2 and 1 mg/mL LD did not induce apoptosis and did not modify collagen synthesis and maturation. Conversely, increased collagen degradation was observed, and AA was not protective against oxidative stress induction in the presence of LD. Our findings suggest that LD does not affect the cell viability of tenocytes and that peritendinous LD injections are safe in this regard. LD-associated collagen degradation and the AA buffer effect are still debatable. Overall, our study contributes to clarifying the effect of LD on tenocytes’ viability and ECM homeostasis and provides new additional information useful for the safe clinical application of this drug and for further analysis. Full article

The aim of this work was to extract phenolic compounds (PCs) from Cistus ladanifer L. post-distillation residues using two different methods (solid–liquid extraction (SLE) and subcritical water extraction (SWE)) and to compare the extracts’ total phenolic content (TPC) and antioxidant activity (AA) by 1,1-diphenyl-2-picrylhydrazyl radical (DPPH^•) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS^•+) scavenging activities, as well as by the ferric-reducing antioxidant power (FRAP) assay. SWE extraction displayed a higher TPC value (increased from 146.53 ± 11.68 to 276.37 ± 20.59 mg gallic acid equivalents (GAEs)/g extract dry weight (dw)) and higher AA in the DPPH^• (increased from 334.27 ± 36.06 to 532.17 ± 66.38 mg Trolox equivalents (TEs)/g extract dw), ABTS^•+ (increased from 438.07 ± 77.22 to 594.08 ± 33.57 mg TEs/g extract dw), and FRAP (increased from 10.91 ± 2.03 to 170.26 ± 25.36 mg ascorbic acid equivalents (AAEs)/g extract dw) assays. These results demonstrate the importance of the extraction method in PC extraction and the antioxidant power of the extracts produced. These results provide critical insights into the potential application of C. ladanifer post-distillation residues and the production of polyphenol rich extracts that might be useful in the food, cosmetic, and pharmaceutical sectors. Full article

Gold nanoparticles (AuNPs) anchored on graphene oxide (GO) have had a significant interest for their unique optical, electrical, and catalytic properties. This study presents an eco-friendly and sustainable synthesis of AuNPs on GO sheets using L-ascorbic acid (L-aa) as a green reducing agent and polyvinylpyrrolidone (PVP) as a stabilizer. The effect of reductant concentration on nanoparticle morphology was systematically investigated using UV–Visible spectroscopy and transmission electron microscopy (TEM). Results indicate the formation of AuNPs anchored on GO sheets and that an increase in the L-aa amount leads to both an increase in nanoparticle size and a morphological transition from spherical to irregular structures. The simultaneous nucleation and growth processes result in the formation of multiple families of nanostructures, as confirmed by TEM analysis, which reveals two distinct size distributions. At higher L-aa concentrations, the nanoparticles shape evolves into irregular morphologies due to selective growth along a preferential facet. This approach not only enables precise control over AuNP size and shape but also aligns with green chemistry principles, making it a promising route for applications in plasmonics, sensors, and photothermal therapy. Full article

Reactive oxygen species (ROS) contribute to cerebral damage in transient cerebral ischemia, making their elimination a key therapeutic target. Osteogenic disorder Shionogi (ODS) rats, which lack endogenous L-ascorbic acid (AA) synthesis, serve as a useful model for investigating AA’s protective effects against ischemic brain injury. ODS rats were given an AA-free diet (0% AA), 0.1% AA, or 1% AA in drinking water for two weeks before undergoing middle cerebral artery occlusion and reperfusion (MCAO/Re). The 0% AA group exhibited pronounced damage following MCAO/Re, characterized by the induction of lipid peroxidation, O₂⁻ production, inflammation-related gene expression, and extensive infarct formation. In contrast, the 1% AA group showed reductions in these markers, along with fewer TUNEL-positive cells and a smaller infarct volume. Notably, sodium-dependent vitamin C transporter 2 (SVCT2) expression increased in both two AA-supplemented groups, although the 0.1% AA group did not exhibit sufficient improvement in post-ischemic damage. A two-week intake of AA significantly alleviated MCAO/Re-mediated injuries associated with oxidative stress and inflammation in ODS rats. Sufficient AA intake is thus supposed to mitigate ischemic damage, possibly through SVCT2 upregulation and enhanced AA availability, leading to the suppression of oxidative stress and inflammation. Full article

2-O-β-D-Glucopyranosyl ascorbic acid (AA-2βG), a bioactive ascorbic acid derivative isolated from the fruits of Lycium barbarum L., exhibited significant antiaging effects in Caenorhabditis elegans. It significantly extended their lifespan, enhanced stress resistance, reduced lipofuscin accumulation, and improved their healthspan, while strengthening antioxidant defenses. Transcriptomic analysis identified the insulin/insulin-like growth factor (IGF)-1 signaling pathway as a key regulator, with quantitative real-time polymerase chain reaction confirming the upregulation of longevity-associated genes. Functional studies showed that the transcription factors DAF-16, HSF-1, and SIR-2.1 were essential for the lifespan-extending effects of AA-2βG, as mutations in these genes abolished lifespan extension. Moreover, 16S rRNA sequencing revealed that AA-2βG modulated gut microbiota by increasing longevity-associated taxa and reducing pro-aging species, with these alterations linked to metabolic pathways. These findings suggest that AA-2βG exerts antiaging effects through the coordinated regulation of the IIS pathway and gut microbiota composition, highlighting its potential as a natural geroprotective compound. Full article

A polyoxometalate-based metal–organic complex with the ability to treat pollutants in water was obtained under hydrothermal conditions, namely [Ni(H₂L)(HL)₂](PMo₁₂O₄₀)·3H₃O·4H₂O (1) (H₂L = 4,4′-(1H,1′H-[2,2′-biimidazole]-1,1′-diyl)dibenzoicacid). Structural analysis reveals that the [Ni(H₂L)(HL)₂] units are interconnected into a 2D layer via hydrogen bonds between adjacent carboxyl groups and water molecules of crystallization. [PMo₁₂O₄₀]³⁻ anions are embedded within the larger pores of the layer and are connected to the adjacent layers through hydrogen bonds, ultimately expanding the structure into a 3D supramolecular architecture. The intermolecular interactions were studied via Hirshfeld surface (HS) analysis. Electrochemical performance tests reveal that 1 exhibits electrocatalytic activity toward the oxidation and reduction of diverse pollutants in water, including NO₂⁻, Cr(VI), BrO₃⁻, Fe(III), and ascorbic acid (AA). Additionally, it can also serve as an amperometric sensor for the detection of BrO₃⁻ and Cr(VI). Photocatalytic studies reveal that compound 1 functions as a bifunctional photocatalyst, which not only achieves efficient degradation of organic dyes but also demonstrates remarkable reduction efficiency for toxic Cr(VI). Compound 1 demonstrates significant potential for practical water remediation applications. Full article

Acne vulgaris is one of the most common skin diseases, and its development is closely linked to the overgrowth of the bacterium Cutibacterium acnes. More than half of the strains of this bacterium are resistant to antibiotics, which has prompted scientists to look for alternatives, such as antibacterial peptides, that can replace traditional drugs. Due to its antioxidant properties, ascorbic acid may be a promising ally in the treatment of acne. The aim of our study was to evaluate the effect of peptide (KWK)₂-KWWW-NH₂(P5) in the presence of ascorbic acid (AA) and its derivative (3-O-ethyl-L-ascorbic acid, EAA) on the stability and organization of phosphatidylinositol monolayers (PI) at temperatures of 25–35 °C. This study showed that the monolayers were in the expanded liquid state (35.28–49.95 mN/m) or in the transition between the expanded liquid and condensed phases (51.50–57.49 mN/m). Compression and decompression isotherms indicated the highest flexibility of the PI + P5 system, where the compression reversibility coefficient of isotherm values ranged from 80.59% to 97.77% and increased for each loop with increasing temperature. At 35 °C, the surface pressure of the monolayer in the PI + P5, PI + P5 + AA and PI + P5 + EAA systems changed less with time. Full article

Nanoparticles are proposed as alternatives to traditional antimicrobial agents. By manipulating a nanoparticle’s core and surface coating, antimicrobial effects against various microbial populations can be customized, known as the “designer effect”. However, the antimicrobial properties of nanoparticle core–coating combinations are understudied; little research exists on their effects on diverse bacteria. The antimicrobial effects of surface-stabilized zero-valent iron nanoparticles (FeNPs) are particularly interesting due to their stability in water and ferromagnetic properties. This study explores the impact of FeNPs coated with three surface coatings on six diverse bacterial species. The FeNPs were synthesized and capped with L-ascorbic acid (AA), cetyltrimethylammonium bromide (CTAB), or polyvinylpyrrolidone (PVP) using a bottom-up approach. Zone of inhibition (ZOI) values, assessed through the disc diffusion assay, indicated that AA-FeNPs and CTAB-FeNPs displayed the most potent antibacterial activity. Bacteria inhibition results ranked from most sensitive to least sensitive are the following: Bacillus nealsonii > Escherichia coli > Staphylococcus aureus > Delftia acidovorans > Chryseobacterium sp. > Sphingobacterium multivorum. Comparisons using ordinal regression and generalized linear mixed models revealed significant differences in bacterial responses to the different coatings and nanoparticle concentrations. The statistical model results are in agreement, thus increasing confidence in these conclusions. This study supports the feasibility of the “designer nanoparticle” concept and offers a framework for future research. Full article

L-ascorbic acid (vitamin C, AA) is widely present in plants, but humans lack the ability to synthesize it independently. As a potent reducing agent, AA is susceptible to oxidation, making the enhancement of its stability crucial. 2-O-β-D-glucopyranosyl-L-ascorbic acid (AA-2βG) is a stable natural derivative of AA with glycosylation, initially discovered in the fruits of Lycium barbarum. Understanding the biosynthesis of AA-2βG is crucial for enhancing its production in L. barbarum. While the established biosynthesis pathway of AA constitutes the upstream of AA-2βG biosynthesis, the conclusive step of β-glycosylation remains unclear. We identified a L. barbarum cultivar by UPLC, ZN01, with a high content of AA-2βG, and compared its leaves, immature fruits, and mature fruits to a normal AA-2βG content L. barbarum cultivar for metabolomic and transcriptomic analysis. The RNA-seq and RT-qPCR analysis revealed that the expression levels of genes involved in the AA biosynthesis pathway did not consistently correlate with AA-2βG content, suggesting that the final glycosylation step may be a key determinant of AA-2βG accumulation. Subsequently, utilizing phylogenetic and co-expression analysis, we identified ten UDP-glycosyltransferases (UGTs) and three β-glucosidases (BGLUs) which may be involved in the crucial step of the conversion from AA to AA-2βG, and the UGTs’ activities were predicted through molecular docking. Lastly, we speculated that the presence of the glycosylation process of AA might have a crucial role in maintaining AA homeostasis in L. barbarum, and deliberated on potential correlations between AA, carotenoids, and anthocyanins. Our integrated multi-omics analysis provides valuable insights into AA-2βG biosynthesis in L. barbarum, identifying thirteen candidate genes and highlighting the complex interplay between AA, carotenoids, and anthocyanins. These findings have implications for improving AA-2βG content in L. barbarum. Full article