Cupric Ion Research Articles

Chemical composition, antioxidant and multi-enzymatic inhibitory potential of licorice harvested from wild populations in Iraq

The current work focuses on comparing the chemical composition, the antioxidant activities and the enzyme inhibitory properties of licorice collected from ecologically distinct regions of Iraq, namely: Wasit and Al-Diwaniyah. The chemical compositions of the aerial parts volatile oils, extracted via hydrodistillation, were characterized by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC–MS) techniques. Furthermore, the evaluation of enzyme inhibitory properties of both samples against acetylcholinesterase, butyrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase were performed. Subsequently, the antioxidant properties were assessed using DPPH and ABTS radical scavenging methods, cupric and Ferric reducing power (CUPRAC and FRAP), metal chelating ability (MCA) and phosphomolybdenum (PBD) assay. Thus, the chemical analysis showed the richness of Glycyrrhiza glabra Linn. volatile oils in oxygenated aliphatic hydrocarbons, with Palmitic acid identified as the major constituent (41.1%-51.6%). Conclusively and as a result of antioxidant assays, licorice from Al-Diwaniyah region was more active than same specie located in Wasit. Both volatile oils exhibited significant cupric ion reducing antioxidant capacity with values ranging between (36.66 and 41.68 mg TE/g). Moreover, G. glabra presented a significant anti-tyrosinase activity, with inhibition values of 58.33 and 52.53 mg KAE/g for Wasit and AL-Diwaniyah populations respectively.

Sphalerite Leaching in Acid Media: a Review

The reserves of rich ores, from which the production of zinc by the existing conventional roasting-leaching-electrowinning process is technologically possible and economically justified, are decreasing year by year. For this reason, increasing attention has been directed towards researching the possibility of obtaining zinc from complex polymetallic ores with a low metal content, adhering to sustainable development goals following strict environmental regulations. Leaching procedures are commonly utilized for the processing of such mineral raw materials.As sphalerite is the widespread and most significant mineral of zinc sulfide, a large part of the research focuses on studying the behavior of sphalerite in the leaching process. This paper reviews the existing knowledge about the leaching of sphalerite in acidic solutions as well as the phenomena accompanying the dissolution process. Special attention is given to research related to the kinetics and mechanism of sphalerite oxidation in an acidic medium influenced by various oxidants, such as hydrogen peroxide, oxygen, dichromate ions, nitrate and nitrite ions, ferric and cupric ions, and others. All these results enable the development of new technological procedures to produce zinc from low-grade and complex ores while meeting increasingly rigorous environmental requirements.

Stress of cupric ion and oxytetracycline in Chlorella vulgaris cultured in swine wastewater

Chlorella culturing has the advantages in treatment of wastewater including swine wastewater from anaerobic digesters due to the product of biolipids and the uptake of carbon dioxide. However, there often exist high concentrations of antibiotics and heavy metals in swine wastewater which could be toxic to chlorella and harmful to the biological systems. This study examined the stress of cupric ion and oxytetracycline (OTC) at various concentrations on the nutrient removal and biomass growth in Chlorella vulgaris culturing in swine wastewater from anaerobic digesters, and its biochemical responses were also studied. Results showed that dynamic hormesis of either OTC concentration or cupric ion one on Chlorella vulgaris were confirmed separately, and the presence of OTC not only did not limit biomass growth and lipids content of Chlorella vulgaris but also could mitigate the toxicity of cupric ion on Chlorella vulgaris in combined stress of Cu2+ and OTC. Extracellular polymeric substances (EPS) of Chlorella vulgaris were used to explain the mechanisms of stress for the first time. The content of proteins and carbohydrates in EPS increased, and the fluorescence spectrum intensity of tightly-bound EPS (TB-EPS) of Chlorella vulgaris decreased with increasing concentration of stress because Cu2+ and OTC may be chelated with proteins of TB-EPS to form non-fluorescent characteristic chelates. The low concentration of Cu2+ (≤1.0 mg/L) could enhance the protein content and promote the activity of superoxide dismutase (SOD) while these parameters were decreased drastically under 2.0 mg/L of Cu2+. The activity of adenosine triphosphatase (ATPase) and glutathione (GSH) enhanced with the increase of OTC concentration under combined stress. This study helps to comprehend the impact mechanisms of stress on Chlorella vulgaris and provides a novel strategy to improve the stability of microalgae systems for wastewater treatment.

Influence of Cupric (Cu2+) Ions on the Iron Oxidation Mechanism by DNA-Binding Protein from Starved Cells (Dps) from Marinobacter nauticus.

Dps proteins (DNA-binding proteins from starved cells) are multifunctional stress defense proteins from the Ferritin family expressed in Prokarya during starvation and/or acute oxidative stress. Besides shielding bacterial DNA through binding and condensation, Dps proteins protect the cell from reactive oxygen species by oxidizing and storing ferrous ions within their cavity, using either hydrogen peroxide or molecular oxygen as the co-substrate, thus reducing the toxic effects of Fenton reactions. Interestingly, the interaction between Dps and transition metals (other than iron) is a known but relatively uncharacterized phenomenon. The impact of non-iron metals on the structure and function of Dps proteins is a current topic of research. This work focuses on the interaction between the Dps from Marinobacter nauticus (a marine facultative anaerobe bacterium capable of degrading petroleum hydrocarbons) and the cupric ion (Cu2+), one of the transition metals of greater biological relevance. Results obtained using electron paramagnetic resonance (EPR), Mössbauer and UV/Visible spectroscopies revealed that Cu2+ ions bind to specific binding sites in Dps, exerting a rate-enhancing effect on the ferroxidation reaction in the presence of molecular oxygen and directly oxidizing ferrous ions when no other co-substrate is present, in a yet uncharacterized redox reaction. This prompts additional research on the catalytic properties of Dps proteins.

Eco-friendly ink formulation of column purified carbon dots from GABA for anticounterfeiting applications

Forgery of valuable products causes a negative impact on the society as well as the economy of the country. There is a growing demand to not only differentiate or authenticate genuine documents/products but also to protect their integrity. Carbon dots (CDs) are a class of fluorescent nanomaterials that are well-known for their facile synthesis, good photostability and less toxicity profile. The current research work focuses on the preparation of CDs via hydrothermal method using γ-aminobutyric acid (GABA) that contains amino and carboxylic groups. Column chromatography technique is adopted to purify the GABA-derived CDs from the reactants and by-products. The fourth fraction obtained after column purification containing CDs with fluorescence emission in the visible region is chosen for further studies. The presence of spherical CDs confirmed through TEM imaging are chemically characterised using SAED, EDS, DLS, FTIR, XPS, Raman and XRD spectroscopy. The blue (λem = 490 nm) and green (λem = 538 nm) emitting CDs present in the fourth fraction displayed a fluorescence lifetime of 1.90 ns and 2.02 ns. Theoretical studies are performed using B3LYP/6-31G(d,p) theory level on different plausible structures. The HOMO-LUMO band gap of 2.3 eV deduced using DFT calculation is in close agreement with the optical band gap of 2.6 eV derived from Tauc plot. A complex forming mechanism is proposed for the fluorescence quenching of CDs upon examining the EDS data of the precipitate obtained upon addition of cupric ions. Further, the CDs are used as pigments to formulate a water-based ink for flexographic printing on UV-dull paper substrate. The printed samples exhibited good colorimetric values, lightfastness, and rub resistance. The security features of the ink film include an UV-induced yellow fluorescence, which will be known to the forger and a secondary quenching of fluorescence when exposed to cupric ions, which can be used by the user to validate document/product authenticity. This stimulus responsive optical property is also explored in the design of ionochromic security paper based on cupric ion induced fluorescence quenching of CDs for data storage and decryption. Moreover, the lesser surface roughness and electrical parameter values obtained for the print proofs could be further explored for the potential application of CD-derived ink in electronic anticounterfeiting.

The Analysis of Antioxidant Capacities and Sensory in Sea Grapes (Caulerpa racemosa) Powdered Drink as a Therapeutic Obesity

Background: Obesity is a global problem which increasing simultaneously. The high-fat accumulation in the body will result from mild chronic inflammation. Developing a local drink based on seagrapes (Caulerpa racemose) is thought to have a high antioxidant capacity and the potential to become an alternative therapeutic drink for obese people. Seagrapes are easily damaged, so proper drying is needed to maintain antioxidant potential and assisted by adding gum arabic to increase the acceptability. Objectives: To analyze the antioxidant capacity and sensory of sea grapes powder drink (Caulerpa racemose). Methods: The design experiment research was utterly randomized and only used one gum Arabic treatment with a 2.5, 5, and 10% concentration and three replication as sea grapes powder drink samples. The samples were analyzed to seek the antioxidant capacity of DPPH (2,2-diphenyi-1-picrylhydrazyl), CUPRAC (Cupric Ion Reducing Antioxidant Capacity), and FRAP (Ferric Reducing Antioxidant Power). Then research data were analyzed by employing ANOVA and Duncan's follow-up test. Results: The higher concentration of gum Arabic has significantly increased the antioxidant capacity. DPPH, CUPRAC, and FRAP values in 10% gum Arabic concentration were 13.21±0.1 mg/100 g, 25.26±0.5 mg, and 2.89±0.3mg/g. Based on the sensory test results, the panelists preferred the 10% gum Arabic concentration because the color is lighter, can minimize odor and viscosity, and taste better. Conclusions: Seagrapes powder drink with a concentration of 10% gum Arabic has the potential as a therapeutic obesity with the highest antioxidant capacity and is sensory acceptable.

Selective determination of cuprous ion in copper dissolving solution based on bathocuproine-modified expanded graphite electrode.

The presence of cuprous ions in the copper-dissolving solution significantly affects the microstructure of copper plated surface. Fewer quantitative analyses of cuprous ions in the copper foil productive process had rarely been involved so far. In the present work, a novel electrochemical sensor of the bathocuproine (BCP) modified expanded graphite (EG) electrode was developed for the selective determination of cuprous ions. EG has a large surface area, good adsorption, and excellent electrochemical performance which remarkably promoted analytical sensitivity. Meanwhile, the selective determination of the BCP-EG electrode for cuprous ions in the coexistence of ten thousand times of copper ions have been achieved on the benefit of the special coordination of BCP to cuprous ions. In the coexistence of 50g/L copper ions, the analytical performance of the BCP-EG electrode for the determination of cuprous ions had been examined. The results represented a wide detection range of cuprous ions in the range of 1.0μg/L-5.0mg/L, with a low detection limit of 0.18μg/L (S/N = 3) and the BCP-EG electrode has great selectivity to cuprous ions in presence of various interferences. The analytical selectively for cuprous ions supported by the proposed electrode would be a potential analytical tool for quality improvement in electrolytic copper foil manufacturing.

Comparison of force fields to study the zinc-finger containing protein NPL4, a target for disulfiram in cancer therapy

Molecular dynamics (MD) simulations are a powerful approach to studying the structure and dynamics of proteins related to health and disease. Advances in the MD field allow modeling proteins with high accuracy. However, modeling metal ions and their interactions with proteins is still challenging. NPL4 is a zinc-binding protein and works as a cofactor for p97 to regulate protein homeostasis. NPL4 is of biomedical importance and has been proposed as the target of disulfiram, a drug recently repurposed for cancer treatment. Experimental studies proposed that the disulfiram metabolites, bis-(diethyldithiocarbamate)‑copper and cupric ions, induce NPL4 misfolding and aggregation. However, the molecular details of their interactions with NPL4 and consequent structural effects are still elusive. Here, biomolecular simulations can help to shed light on the related structural details. To apply MD simulations to NPL4 and its interaction with copper the first important step is identifying a suitable force field to describe the protein in its zinc-bound states. We examined different sets of non-bonded parameters because we want to study the misfolding mechanism and cannot rule out that the zinc may detach from the protein during the process and copper replaces it. We investigated the force-field ability to model the coordination geometry of the metal ions by comparing the results from MD simulations with optimized geometries from quantum mechanics (QM) calculations using model systems of NPL4. Furthermore, we investigated the performance of a force field including bonded parameters to treat copper ions in NPL4 that we obtained based on QM calculations.

Simple assay for quantifying xanthine oxidase activity

This paper reports a sensitive method for assaying xanthine oxidase (XO) enzyme activity. XO produces hydrogen peroxide (H2O2) and superoxide anion radicals (O2•−), promoting the development of oxidative stress-related diseases, and is inhibited by various plant extracts. XO activity is quantified by incubating enzyme samples with an appropriate xanthine concentration as the substrate. The proposed method requires XO activity to be quantified based on H2O2 generation using a 3,3′,5,5′-tetramethylbenzidine (TMB)-H2O2 system catalyzed by cupric ions. After a 30-min incubation at 37 °C, sufficient cupric ion and TMB amounts are added. The assay produces optical signals that can be visually recognized or detected with a UV–visible spectrometer. A direct correlation was found between XO activity and the absorbance at 450 nm of the resulting di-imine (dication) yellow product. The proposed method uses sodium azide to prevent catalase enzyme interference. The new assay's function was confirmed using the TMB-XO assay and a Bland–Altman plot. The resulting correlation coefficient was 0.9976. The innovative assay was relatively precise and comparable to the comparison protocols. In conclusion, the presented method is very efficient at measuring XO activity.

Conjunction of ferric ion with chloride ion facilitated zero-valent copper/air system to eliminate paracetamol: Mechanistic insights and performance evaluation

Zero-valent copper/air process was studied in degrading contaminants owing to in-site generation of hydrogen peroxide and reactive oxygen species, while its oxidation efficacy was restrained by the dismutation of cuprous ion. In this study, when the dosages of paracetamol, ferric ion, chloride ion and zero-valent copper were respectively 10 μM, 40 μM, 2 mM and 0.2 g/L at pH 3.0, the paracetamol elimination was greatly enhanced and increased from 9.2% to 76.5% within 30 min with adding both ferric ion and chloride ion in the zero-valent copper/air process. Hydroxyl radical and reactive chlorine species were identified as the dominant reactive oxygen species, and the contribution rates of hydroxyl radical and reactive chlorine species to eliminating paracetamol were respectively 68.2% and 28.9%. In the proposed system, zero-valent copper and cuprous ion expedited the ferric/ferrous circulation, conducing to the production of reactive oxygen species. Moreover, chloride ion coupled with cuprous ion producing the cuprous chloride complexes, and chloride ion contributed to the comproportionation between zero-valent copper with cupric ion to form cuprous chloride, receding the dismutation of cuprous ion and contributing to the formation of hydrogen peroxide and reactive oxygen species. When zero-valent copper reused for three times in the proposed system, the degradation of paracetamol reached 62%. After we increased the end pH to > 7.0 and leaching, the total copper of reaction solution was under 0.85 mg/L and the acute toxicity had no insignificant increase for discharge water. The study provided a new idea to enhance zero-valent copper/air system for the purification of pollutants.

Insulator-to-metal-like transition in thin films of a biological metal-organic framework

Temperature-induced insulator-to-metal transitions (IMTs) where the electrical resistivity can be altered by over tens of orders of magnitude are most often accompanied by structural phase transition in the system. Here, we demonstrate an insulator-to-metal-like transition (IMLT) at 333 K in thin films of a biological metal-organic framework (bio-MOF) which was generated upon an extended coordination of the cystine (dimer of amino acid cysteine) ligand with cupric ion (spin-1/2 system) – without appreciable change in the structure. Bio-MOFs are crystalline porous solids and a subclass of conventional MOFs where physiological functionalities of bio-molecular ligands along with the structural diversity can primarily be utilized for various biomedical applications. MOFs are usually electrical insulators (so as our expectation with bio-MOFs) and can be bestowed with reasonable electrical conductivity by the design. This discovery of electronically driven IMLT opens new opportunities for bio-MOFs, to emerge as strongly correlated reticular materials with thin film device functionalities.

Cupric ion decorated ammonium polyphosphate as an effective flame retardant for thermoplastic polyurethane

Cupric ion decorated ammonium polyphosphate as an effective flame retardant for thermoplastic polyurethane

Influence of Deposition Parameters for Cu2O and CuO Thin Films by Electrodeposition Technique: A Short Review

The transition metal oxide-based nanomaterial attracted researchers for its various applications due to its interesting physical, chemical, and optical properties. Copper oxide thin films with different oxidation states were prepared on various transparent, nontransparent nature conducting substrates from the acidic and alkaline medium by electrodeposition technique. The deposition parameters such as potential, bath temperature, solution pH, and deposition time determine the physical, chemical, and optical properties. The complexing agents such as sodium thiosulfate, lactic acid, citric acid, and triethanolamine determine the stability of cuprous and cupric ions in the deposited films. Optical properties reported that the deposited films have direct band gap value 1.3 and 3.7 eV represents the absorbance of the deposited films in the visible region of solar spectrum. The absorbance of light in visible region, good electrical conductivity, and various nanostructure morphologies with the environment-friendly constituents are the distinctive properties of copper metal oxides.

A novel water disinfection method via cuprous ion generation in a copper ferrite/sulfite system and associated mechanism

Aqueous pathogenic microorganisms pose a significant risk to public health, but conventional disinfection methods present numerous drawbacks. By employing bactericidal tests, radical quenching experiments, and quantitative toxicogenomic assay, this study aimed to evaluate the effectiveness and associated cellular mechanism of a novel disinfection process combining recyclable copper ferrite (CuFe2O4) nanoparticles with sulfite. At the optimal CuFe2O4 (800 mg/L) and sulfite (4 mM) concentrations determined, the CuFe2O4/sulfite system inactivated 4.65-log (>99.99 %) of Escherichia coli cells at an initial concentration of 108 colony-forming units (CFU)/mL in 3 h. Meanwhile, the E. coli cells at the initial concentration of 104 − 106 CFU/mL were 100 % inactivated within 1–2 h. Cuprous ions (Cu(I)) rather than sulfate radicals (SO4•−) played the dominant role in the inactivation process, by breaking the cell membrane, damaging intracellular components (such as adenosine triphosphate and nicotinamide adenine dinucleotide), and stimulating increased reactive oxygen species production. Correspondingly, the toxicogenomics-based toxicity assessment indicated the induction of oxidative damage to exposed cells as a dominant molecular-level disinfection mechanism of the CuFe2O4/sulfite system. Moreover, the CuFe2O4/sulfite system exhibited comparable inactivation efficiency against three other bacterial species, while gram-positive strains (Staphylococcus aureus and Bacillus subtilis) were more susceptible to this system than gram-negative ones (Pseudomonas aeruginosa and E. coli). The magnetic recyclable CuFe2O4/sulfite system is a promising water disinfection method owing to its efficacy, convenience, and environmental sustainability.

Antioxidant activity of 1.3-bis(p-hydroxyphenyl)urea by CUPRAC and FRAP methods

An imbalance in the number of free radicals produced in the body can result in oxidative stress. Excessive oxidative stress can lead to chronic inflammation, which in turn can lead to most chronic diseases. Inflammation is related to oxidation through increased reactive oxidative stress, which can target modulators associated with inflammation, such as inflammatory cytokines. Antioxidants can inhibit or stop oxidation by protecting the body and neutralizing free radicals. 1.3-bis(p-hydroxyphenyl)urea is a modification of p-aminophenol and has hepatotoxic side effects such as those caused by acetaminophen. This compound can relieve pain, is anti-inflammatory, and has fewer side effects. This research was conducted to evaluate the antioxidant activity of 1.3-bis(p-hydroxyphenyl)urea using the CUPRAC (Cupric Ion Reducing Antioxidant Capacity) method and the FRAP (Ferric Reducing Antioxidant Power) method. The results of the CUPRAC method research show that the 1.3-bis(p-hydroxyphenyl)urea compound has an IC50 value of 4.40 ± 0.07 μg/mL. Meanwhile, the FRAP method was 29.36 ± 1.20 μg/mL. Apart from suppressing inflammation, this compound has the potential to be an antioxidant compound.

Screening of Antiglaucoma, Antidiabetic, Anti-Alzheimer, and Antioxidant Activities of Astragalus alopecurus Pall-Analysis of Phenolics Profiles by LC-MS/MS.

Astragalus species are traditionally used for diabetes, ulcers, leukemia, wounds, stomachaches, sore throats, abdominal pain, and toothaches. Although the preventive effects of Astragalus species against diseases are known, there is no record of the therapeutic effects of Astragalus alopecurus. In this study, we aimed to evaluate the in vitro antiglaucoma, antidiabetic, anti-Alzheimer's disease, and antioxidant activities of the methanolic (MEAA) and water (WEAA) extracts of the aerial part of A. alopecurus. Additionally, its phenolic compound profiles were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). MEAA and WEAA were evaluated for their inhibition ability on α-glycosidase, α-amylase, acetylcholinesterase (AChE), and human carbonic anhydrase II (hCA II) enzymes. The phenolic compounds of MEAA were analyzed by LC-MS/MS. Furthermore, total phenolic and flavonoid contents were determined. In this context, the antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), N,N-dimethyl-p-phenylene diamine (DMPD), ferric reducing antioxidant power (FRAP), cupric ions (Cu2+) reducing antioxidant capacity (CUPRAC), ferric ions (Fe3+) reducing, and ferrous ions (Fe2+) chelating methods. MEAA and WEAA had IC50 values of 9.07 and 2.24 μg/mL for α-glycosidase, 693.15 and 346.58 μg/mL for α-amylase, 1.99 and 2.45 μg/mL for AChE, and 147.7 and 171.7 μg/mL for hCA II. While the total phenolic amounts in MEAA and WEAA were 16.00 and 18.50 μg gallic acid equivalent (GAE)/mg extract, the total flavonoid contents in both extracts were calculated as 66.23 and 33.115 μg quercetin equivalent (QE)/mg, respectively. MEAA and WEAA showed, respectively, variable activities on DPPH radical scavenging (IC50: 99.02 and 115.53 μg/mL), ABTS radical scavenging (IC50: 32.21 and 30.22 µg/mL), DMPD radical scavenging (IC50: 231.05 and 65.22 μg/mL), and Fe2+ chelating (IC50: 46.21 and 33.01 μg/mL). MEAA and WEAA reducing abilities were, respectively, Fe3+ reducing (λ700: 0.308 and 0.284), FRAP (λ593: 0.284 and 0.284), and CUPRAC (λ450: 0.163 and 0.137). A total of 35 phenolics were scanned, and 10 phenolic compounds were determined by LC-MS/MS analysis. LC-MS/MS revealed that MEAA mainly contained isorhamnetin, fumaric acid, and rosmarinic acid derivatives. This is the first report indicating that MEAA and WEAA have α-glycosidase, α-amylase, AChE, hCA II inhibition abilities, and antioxidant activities. These results demonstrate the potential of Astragalus species through antioxidant properties and enzyme inhibitor ability traditionally used in medicine. This work provides the foundation for further research into the establishment of novel therapeutics for diabetes, glaucoma, and Alzheimer's disease.

Glutamate, Humic Acids and Their Combination Modulate the Phenolic Profile, Antioxidant Traits, and Enzyme-Inhibition Properties in Lettuce.

Lettuce (Lactuca sativa L., Asteraceae) is a popular vegetable leafy crop playing a relevant role in human nutrition. Nowadays, novel strategies are required to sustainably support plant growth and elicit the biosynthesis of bioactive molecules with functional roles in crops including lettuce. In this work, the polyphenolic profile of lettuce treated with glutamic acid (GA), humic acid (HA), and their combination (GA + HA) was investigated using an untargeted metabolomics phenolic profiling approach based on high-resolution mass spectrometry. Both aerial and root organ parts were considered, and a broad and diverse phenolic profile could be highlighted. The phenolic profile included flavonoids (anthocyanins, flavones, flavanols, and flavonols), phenolic acids (both hydroxycinnamics and hydroxybenzoics), low molecular weight phenolics (tyrosol equivalents), lignans and stilbenes. Overall, GA and HA treatments significantly modulated the biosynthesis of flavanols, lignans, low molecular weight phenolics, phenolic acids, and stilbene. Thereafter, antioxidant capacity was evaluated in vitro with 2,2-diphenyln-1-picrylhydrazyl (DPPH), 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) assays. In addition, this study examined the inhibitory properties of enzymes, including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), tyrosinase, alpha-amylase, and alpha-glucosidase. Compared to individual treatments, the combination of GA + HA showed stronger antioxidant abilities in free radical scavenging and reducing power assays in root samples. Moreover, this combination positively influenced the inhibitory effects of root samples on AChE and BChE and the tyrosinase inhibitory effect of leaf samples. Concerning Pearson's correlations, antioxidant and enzyme inhibition activities were related to phenolic compounds, and lignans in particular correlated with radical scavenging activities. Overall, the tested elicitors could offer promising insights for enhancing the functional properties of lettuce in agricultural treatments.

Microwave irradiation: Reduction of higher alcohols in wine and the effect mechanism by employing model wine

Reduction of higher alcohols contributed more to the aromatic characteristics of wine. In this paper, response surface methodology was used to optimize the parameters of microwave time, temperature, and power to obtain optimal microwave processing conditions for the maximum degradation rate of higher alcohols in model wine solution, and the maximum degradation rate of higher alcohol was 11.21% under optimized microwave conditions of 100 W, 50 °C and 3 min. The possible mechanism of microwave reducing on the higher alcohols was studied at optimized microwave conditions, the results showed that high concentrations of tartaric acid, glyoxylic acid, and ferrous ions could obviously decrease the content of higher alcohols; the content of higher alcohols in low concentrations ethanol and cupric ions was obviously lower than that in high concentration of ethanol and cupric ions; the appropriate (+)-catechin concentration had more obvious effect on higher alcohols content; the mannitol inhibited the degradation of higher alcohols and its subsequent reactions by scavenging free radicals in model wine solution. In summary, all these results could help understand the influence of improvement effect of microwave irradiation on the aromatic characteristics in wine by reducing the contents of higher alcohols.

Enhancement of physicochemical properties, antioxidant, antitumor, and anticoagulant activities via acetylation of Hypsizygus ulmarius polysaccharide

SummaryA polysaccharide (HUP1) was extracted and purified from Hypsizygus ulmarius fruiting bodies and further acetylated (Ac‐HUP1) to improve their physicochemical properties and bioactivities. Chemical and FT‐IR spectrum analyses results indicated differences in functionality and activity between HUP1 and Ac‐HUP1, demonstrating the efficacy of the acetylation. HUP1 has an acetyl group with a degree of substitution (DS) 0.34. The molecular weight of the modified acetylated derivatives was reduced, according to the HPSEC findings. The native and acetylated polysaccharides included varying molar percentages of Ara, Man, Glu, GlcA, and GalA. The Ac‐HUP1 outperformed HUP1 in antioxidant activity using the radical scavengers ABTS, DMPD, DPPH, superoxide, and OH radicals. In addition, Ac‐HUP1 demonstrated higher activity in reducing power using Prussian blue, cupric ion, ferric ion, and phosphomolybdenum, as well as in lipid peroxidation inhibition assay. HUP1 and Ac‐HUP1 inhibited five cancer cells (HT29, PC3, HeLa, Jurkat, and HepG‐2) at concentrations from 10 to 320 μg mL−1, and the impact was more pronounced in acetylated derivative, which was determined by MTT assay. Ac‐HUP1, compared to HUP1, considerably prolonged the APTT, PT, and TT exhibiting anticoagulant activities. Therefore, acetylation modification may improve polysaccharide'sphysicochemical and biological characteristics, allowing them to be employed in the food, nutraceutical, and pharmaceutical industries.

Quantification of underivatized amino acids in solid beverages using high-performance liquid chromatography and a potentiometric detector

The simultaneous quantification of amino acids (AAs) in solid beverages without prior derivatization was explored by high-performance liquid chromatography (HPLC) coupled to a potentiometric detector. Included were threonine, leucine, methionine, phenylalanine, and histidine. The potentiometric detector was made consisting of a copper(II)-selective electrode based on a polyvinyl chloride (PVC) membrane, and the potential changes in the detector were determined according to the coordination interactions between cupric copper ions released from the inner filling solution of the electrode and AAs. Conditions were optimized for effective separation and sensitive detection. Fundamental characteristics such as linearity, limits of detection, limits of quantitation, accuracy, precision, and robustness were validated experimentally. The calibration curves showed a linear relationship between peak heights and the injection concentrations of the AAs. The detection limits down to the sub-micromolar range were achieved under isocratic conditions, outperforming ultraviolet detection. The copper(II)-selective electrode had a minimum lifetime of one month. Some real samples were examined to further demonstrate the feasibility of the proposed approach. The measurement results obtained by the present method were in good agreement with those obtained by the HPLC-mass spectrometry (MS), indicating that the combined HPLC-potentiometric method is a potential option for quantifying AAs.