Antioxidant Activity, Inhibition of Intestinal Cancer Cell Growth and Polyphenolic Compounds of the Seagrass Posidonia oceanica's Extracts from Living Plants and Beach Casts.

The aim of the present study was to investigate the use of Posidonia oceanica for making products beneficial for human health. Firstly, we demonstrated that the antioxidant defense (i.e., SOD and APX activity) of P. oceanica's living leaves (LP) has low efficacy, as they partly neutralize the produced H2O2. However, high H2O2 levels led LP to produce, as a response to oxidative stress, high phenolic content, including chicoric acid, p-coumaric acid, caftaric acid, trans-cinnamic and rutin hydrate, as shown by UHPLC-DAD analysis. In addition, LP extracts inhibited intestinal cancer cell proliferation. Moreover, P. oceanica's beach casts consisting of either Wet 'Necromass' (WNP) or Dry 'Necromass' (DNP) were used for preparing extracts. Both DNP and WNP exhibited antioxidant and antiproliferative activities, although lower as compared to those of LP extracts. Although both P. oceanica's meadows and beach casts are considered priority habitats in the Mediterranean Sea due to their high ecological value, legislation framework for beach casts forbidding their removal is still missing. Our results suggested that both LP and DNP could be utilized for the production of high-added value products promoting human health, provided that a sustainability management strategy would be applied for P. oceanica's meadows and beach casts.

Comprehensive identification of polyphenolic metabolites in aspen knotwood by combination of 2D NMR and HPLC-HRMS.

INTRODUCTION: European aspen (Populus tremula L.) knotwood contains large amounts of polyphenolic metabolites, mainly flavonoids, and can be considered as a promising industrial-scale source of valuable bioactive compounds. Valorization of knotwood extractives requires detailed information on their chemical composition and a relevant analytical methodology. OBJECTIVE: This study proposes combined analytical strategy for non-targeted screening and identification of polyphenolic plant metabolites and is aimed at comprehensive characterization of knotwood extractives. MATERIALS AND METHODS: Aspen knotwood acetone extract with determined antioxidant activity was an object of the study. Two-dimensional NMR spectroscopy with Structure Elucidator expert system was used for preliminary search of major components and specific structures. Liquid chromatography-high-resolution mass spectrometry (HPLC-HRMS) with data-dependent MS/MS spectra acquisition was used as a complementary technique providing molecular-level characterization and identification of the detected metabolites. RESULTS: Twenty-eight phenolic metabolites were found and identified. Among them, flavonoids, aromadendrin and naringenin, as well as their glycosylated derivatives (mainly O-glucosides) and methyl ethers, dominated. Taxifolin and its 7-O-glucoside were detected as minor components. Other detected compounds are represented by p-coumaric acid and its rutinoside and small amounts of glycosylated ferulic acid. Nineteen of the detected compounds were discovered in aspen knotwood for the first time. The results were confirmed by preparative isolation of individual compounds and NMR studies. CONCLUSION: The proposed analytical strategy based on 2D NMR and HPLC-HRMS can be considered a powerful tool in the analysis of plant extractives and allowed for the identification and semi-quantification of a large number of polyphenols in aspen knotwood.

Marine Polyphenols in Cardiovascular Health: Unraveling Structure-Activity Relationships, Mechanisms, and Therapeutic Implications.

Cardiovascular diseases (CVDs) are responsible for significant mortality rates globally that have been raised due to the limitation of the available treatments and prevalence of CVDs. The innovative research and identification of potential preventives for CVDs are essential to alleviate global deaths and complications. The marine environment is a rich source of bioactive substances and provides a unique chemical arsenal against numerous ailments due to its unrivaled biodiversity. Marine polyphenolic compounds (MPCs) are unique because of their structural variety and biologically significant activity. Further, MPCs are well-reported for their valuable biological activities, such as anti-inflammatory, cardioprotective, and antioxidant, demonstrating encouraging results in preventing and treating CVDs. Therefore, investigation of the structure-activity relationship (SAR) between MPCs and CVDs provides insights that reveal how the structural components of these compounds affect their effectiveness. Further, comprehending this correlation is essential for advancing medications and nutraceuticals sourced from marine sources, which could transform the strategy for treating and preventing cardiovascular diseases. Therefore, this study provides a comprehensive analysis of existing research by emphasizing the role of MPCs in CVD treatments and evaluating the SAR between MPCs and CVDs with challenges and future directions.

Polyphenols from Maackia amurensis Heartwood Protect Neuronal Cells from Oxidative Stress and Prevent Herpetic Infection.

Here, we continued the investigation of anti-HSV-1 activity and neuroprotective potential of 14 polyphenolic compounds isolated from Maackia amurensis heartwood. We determined the absolute configurations of asymmetric centers in scirpusin A (13) and maackiazin (10) as 7R,8R and 1″S,2″S, respectively. We showed that dimeric stilbens maackin (9) and scirpusin A (13) possessed the highest anti-HSV-1 activity among polyphenols 1-14. We also studied the effect of polyphenols 9 and 13 on the early stages of HSV-1 infection. Direct interaction with the virus (virucidal activity) was the main mechanism of the antiviral activity of these compounds. The neuroprotective potential of polyphenolic compounds from M. amurensis was studied using models of 6-hydroxydopamine (6-OHDA)-and paraquat (PQ)-induced neurotoxicity. A dimeric stilbene scirpusin A (13) and a flavonoid liquiritigenin (6) were shown to be the most active compounds among the tested polyphenols. These compounds significantly increased the viability of 6-OHDA-and PQ-treated Neuro-2a cells, elevated mitochondrial membrane potential and reduced the intracellular ROS level. We also found that scirpusin A (13), liquiritigenin (6) and retusin (3) considerably increased the percentage of live Neuro-2a cells and decreased the number of early apoptotic cells. Scirpusin A (13) was the most promising compound possessing both anti-HSV-1 activity and neuroprotective potential.

Chemical Constituents of Stinging Nettle (Urtica dioica L.): A Comprehensive Review on Phenolic and Polyphenolic Compounds and Their Bioactivity.

Polyphenolic compounds are of great interest in today's science. Naturally, they occur in plants and other sources in many different forms. Their wide range of biological activity has attracted the attention of the scientific community. One of the sources of phenolic compounds is stinging nettle (Urtica dioica L.), a common plant in almost all parts of the world. A long tradition of utilization and an interesting chemical profile make this plant a fascinating and extensive object of study. The chemical profile also allows this plant to be used as a food and a pigment source in the food, pharmaceutical, and cosmetic industries. Previously conducted studies found phenolic acids and polyphenolic compounds in root, stalk, and stinging nettle leaves. Different extraction techniques were usually used to isolate them from the leaves. Obtained extracts were used to investigate biological activity further or formulate different functional food products. This study aimed to collect all available knowledge about this plant, its chemical composition, and biological activity and to summarize this knowledge with particular attention to polyphenolic compounds and the activity and mechanisms of their actions.

German Chamomile (Matricaria chamomilla L.) Flower Extract, Its Amino Acid Preparations and 3D-Printed Dosage Forms: Phytochemical, Pharmacological, Technological, and Molecular Docking Study.

German chamomile (Matricaria chamomilla L.) is an essential oil- containing medicinal plant used worldwide. The aim of this study was to gain knowledge of the phytochemical composition and the analgesic and soporific activity of Matricaria chamomilla L. (German chamomile) flower extract and its amino acid preparations, to predict the mechanisms of their effects by molecular docking and to develop aqueous printing gels and novel 3D-printed oral dosage forms for the flower extracts. In total, 22 polyphenolic compounds and 14 amino acids were identified and quantified in the M. chamomilla extracts. In vivo animal studies with rodents showed that the oral administration of such extracts revealed the potential for treating of sleep disorders and diseases accompanied by pain. Amino acids were found to potentiate these effects. Glycine enhanced the analgesic activity the most, while lysine and ß-alanine improved the soporific activity. The molecular docking analysis revealed a high probability of γ-aminobutyric acid type A (GABAA) and N-methyl-D-aspartate (NMDA) receptor antagonism and 5-lipoxygenase (LOX-5) inhibition by the extracts. A polyethylene oxide (PEO)-based gel composition with the M. chamomilla extracts was proposed for preparing a novel 3D-printed dosage form for oral administration. These 3D-printed extract preparations can be used, for example, in dietary supplement applications.

Verbascoside: comprehensive review of a phenylethanoid macromolecule and its journey from nature to bench.

Polyphenolic compounds are among the most widely researched compounds for various therapeutic applications. However, naturally occurring phenylethanoid glycosides are least explored under this class of compounds. One such phenylethanoid glycoside, verbascoside (Vb), abundantly found among 200 species of 23 families, has gained recent attention due to its wide-spectrum therapeutic properties such as antioxidant, antimicrobial, anti-inflammatory, neuroprotective, cardioprotective, skin-protective, and anti-cancer. Despite having multiple therapeutic benefits, due to its large size, the compound has poor bioavailability for oral and topical applications. To meet these limitations, current research on Vb focuses on delivering it through nanoformulations. Presently, most developed formulations are liposome based for various applications, such as corneal epithelial wound healing, anti-neuropathic, anti-wrinkle, anti-hyperalgesia, atopic dermatitis, alopecia, and cutaneous wound healing. Multiple studies have confirmed the least acute and sub-acute toxicity for Vb. Few clinical studies have been performed for the therapeutic application of Vb to manage COVID-19, nephropathy, platelet aggregation, chronic primary glomerulonephritis, and acute hepatitis. Recent studies have shown the immense therapeutic potential of Vb in wound healing, dermatitis, neuroprotection, and anti-cancer activities, which creates a need for developing novel formulations for their respective uses. Long-term toxicity studies and techniques for scaling up Vb production by biotechnological approaches should be emphasized.

Pitahaya (Hylocereus ocamponis)-Peel and -Flesh Flour Obtained from Fruit Co-Products-Assessment of Chemical, Techno-Functional and In Vitro Antioxidant Properties.

The aim of this work was to assess the chemical composition and physico-chemical, techno-functional, and in vitro antioxidant properties of flours obtained from the peel and flesh of pitahaya (Hylocereus ocamponis) to determine their potential for use as ingredients for food enrichment. The chemical composition, including total betalains, mineral content, and polyphenolic profile, was determined. The techno-functional properties (water holding, oil holding, and swelling capacities) were also evaluated. For the antioxidant capacity, four different methodologies, namely ferrous ion-chelating ability assay, ferric-reducing antioxidant power assay; 1,1-Diphenyl-2-picrylhydrazyl radical scavenging ability assay, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical assay, were used. Pitahaya-peel flour had higher values for protein (6.72 g/100 g), ash (11.63 g/100 g), and dietary fiber 56.56 g/100 g) than pitahaya-flesh flour, with values of 6.06, 3.63, and 8.22 g/100 g for protein, ash, and dietary fiber, respectively. In the same way, pitahaya peel showed a higher content of minerals, betalains, and polyphenolic compounds than pitahaya-flesh flour, with potassium (4.43 g/100 g), catechin (25.85 mg/g), quercetin-3-rhamnoside (11.66 mg/g) and myricetrin (12.10 mg/g) as principal compounds found in the peel. Again, pitahaya-peel flour showed better techno-functional and antioxidant properties than pitahaya-flesh flour. The results obtained suggest that the flours obtained from the peel and pulp of pitahaya (H. ocamponis) constitute a potential material to be utilized as an ingredient in the food industry due to the high content of bioactive compounds such as betalains, phenolic acids, and flavonoids, with notable antioxidant capacity.

Chinese Artichoke (Stachys affinis Bunge): The Nutritional Profile, Bioactive Profile and Food Applications-A Review.

Stachys affinis Bunge, known as Chinese artichoke, is a perennial plant originating from China, which has uprising scientific interest due to its complex and beneficial content. Chinese artichoke is rich in bioactive compounds useful for human health, including antioxidants, polyphenols, and prebiotics, and its edible tubers are high in essential nutrients and dietary fiber. Studies show its potential as a functional food ingredient in various products like rice bars, bread, and chocolate, enhancing their nutritional and sensory properties. Additionally, Chinese artichoke exhibits significant anti-inflammatory, neuroprotective, and antibacterial activities, warranting further research and utilization in the food industry. This review aims to summarize the existing knowledge of the S. affinis Bunge plant, focusing on its health-promoting aspects.

The Influence of Active Compounds of Chips Made from Different Wood Species on the Antioxidant, Oenological and Sensory Properties of Apple Wines.

Wood chips contain numerous active compounds that can affect the wine's characteristics. They are commonly used in red grape wines, whisky, cherry and brandy, but in fruit wines, production is not typically utilised. The aim of this study was to compare the impact of an oak barrel ageing with the effect of the addition of chips made from various types of wood (oak, maple, cherry, apple) and with various degrees of toasting to the apple wines on their antioxidant, oenological and sensory properties. The oenological parameters, the polyphenols content, antioxidant activity and content of volatile odour-active compounds were assessed. It was shown that ageing in the presence of wood chips had a less noticeable effect on the oenological and sensory parameters of the wine than barrel ageing. Moreover, wood chips used did not significantly affect the acidity, alcohol and extract content of apple wines. Wines aged in the presence of oak chips (particularly lightly toasted) exhibited the greatest increase in polyphenols, while the polyphenol content of wines aged in the presence of other chips was not dependent on their toasting degree. The ageing of fruit wines with wood chips influences the volatile profile and the olfactory sensations, which can improve their quality.

Covalent conjugation of Inca peanut albumin and polyphenols with different phenolic hydroxyl numbers through laccase catalysis to improve functional properties.

BACKGROUND: Enzymatic crosslinking is a method that can be used to modify Inca peanut albumin (IPA) using polyphenols, and provides desirable functionalities; however, the effect of polyphenol structures on conjugate properties is unclear. In this study, we selected four polyphenols with different numbers of phenolic hydroxyl groups [para-hydroxybenzoic acid (HBA), protocatechuic acid (PCA), gallic acid (GA), and epigallocatechin gallate (EGCG)] for covalent modification of IPA by enzymatic crosslinking, and explored the structure-function changes of the IPA-polyphenol conjugates. RESULTS: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis showed that laccase successfully promoted covalent crosslinking of IPA with polyphenols, with the order of degree of conjugation as EGCG > GA > PCA > HBA, the IPA-EGCG conjugate showed the highest polyphenol binding equivalents (98.35 g kg-1 protein), and a significant reduction in the content of free amino, sulfhydryl, and tyrosine group. The oxidation of polyphenols by laccase forms quinone or semiquinone radicals that are covalently crosslinked to the reactive groups of IPA, leading to significant changes in the secondary and tertiary structures of IPA, with spherical structures transforming into dense lamellar structures. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability and emulsification stability of IPA-EGCG conjugates improved by almost 6-fold and 2.7-fold, respectively, compared with those of unmodified IPA. CONCLUSION: These data suggest that the higher the number of polyphenol hydroxyl groups, the higher the degree of IPA-polyphenol conjugation; additionally, enzymatic crosslinking can significantly improve the functional properties of IPA. © 2024 Society of Chemical Industry.

Catechol-Amyloid Interactions.

This review introduces multifaceted mutual interactions between molecules containing a catechol moiety and aggregation-prone proteins. The complex relationships between these two molecular species have previously been elucidated primarily in a unidirectional manner, as demonstrated in cases involving the development of catechol-based inhibitors for amyloid aggregation and the elucidation of the role of functional amyloid fibers in melanin biosynthesis. This review aims to consolidate scattered clues pertaining to catechol-based amyloid inhibitors, functional amyloid scaffold of melanin biosynthesis, and chemically designed peptide fibers for providing chemical insights into the role of the local three-dimensional orientation of functional groups in manifesting such interactions. These orientations may play crucial, yet undiscovered, roles in various supramolecular structures.

Plant-derived polyphenolic compounds: nanodelivery through polysaccharide-based systems to improve the biological properties.

Plant-derived polyphenols are naturally occurring compounds widely distributed in plants. They have received greater attention in the food and pharmaceutical industries due to their potential health benefits, reducing the risk of some chronic diseases due to their antioxidant, anti-inflammatory, anticancer, cardioprotective, and neuro-action properties. Polyphenolic compounds orally administered can be used as adjuvants in several treatments but with restricted uses due to chemical instability. The review discusses the different structural compositions of polyphenols and their influence on chemical stability. Despite the potential and wide applications, there is a need to improve the delivery of polyphenolics to target the human intestine without massive chemical modifications. Oral administration of polyphenols is unfeasible due to instability, low bioaccessibility, and limited bioavailability. Nano-delivery systems based on polysaccharides (starch, pectin, chitosan, and cellulose) have been identified as a viable option for oral ingestion, potentiate biological effects, and direct-controlled delivery in specific tissues. The time and dose can be individualized for specific diseases, such as intestinal cancer. This review will address the mechanisms by which polysaccharides-based nanostructured systems can protect against degradation and enhance intestinal permeation, oral bioavailability, and the potential application of polysaccharides as nanocarriers for the controlled and targeted delivery of polyphenolic compounds.

Antioxidant, antibacterial, and antileishmanial potential of Micromeria nervosa extracts and molecular mechanism of action of the bioactive compound.

AIMS: This study aimed to determine the antibacterial and antileishmanial potential of Micromeria nervosa extracts. The identification of the antileishmanial compound and the study of its molecular mechanism of action have also been undertaken. METHODS AND RESULTS: Ethanol extract showed high polyphenol content and diethyl ether extract exhibited high DPPH scavenging and low beta-carotene bleaching activity (IC50 = 13.04 ± 0.99 and 200.18 ± 3.32 µg mL-1, respectively). However, diethyl ether extract displayed high antibacterial activity against Gram-positive strains including methicillin-resistant Staphylococcus aureus (MIC = 31.25 µg mL-1), Staph. aureus ATCC6538 (MIC = 62.5 µg mL-1), and Listeria monocytogenes ATCC 19115 (MIC = 125 µg mL-1), as well as high antileishmanial activity against the promastigote forms of L. infantum and L. major (IC50 = 11.45 and 14.53 µg mL-1, respectively). The active compound was purified using bioassay-guided fractionation and thin layer chromatography, and identified as ursolic acid using high-performance liquid chromatography coupled with a photodiode array and mass spectrometry. The purified compound was strongly inhibitory against the promastigote and amastigote forms of L. infantum and L. major (IC50 = 5.87 and 6.95 µg mL-1 versus 9.56 and 10. 68 µg mL-1, respectively) without overt cytotoxicity against Raw 264.7 macrophage cells (SI = 13.53 and 11.43, respectively). The commercial compound (ursolic acid) showed similar activity against amastigotes and promastigotes forms of L. infantum and L. major. Moreover, its molecular mode of action against leishmaniasis seems to involve the expression of the ODC and SPS genes involved in thiol pathway. CONCLUSION: Extracts of M. nervosa can be considered as a potential alternative to antimicrobial and antileishmanial drugs.

Neuroprotective and Antiherpetic Properties of Polyphenolic Compounds from Maackia amurensis Heartwood.

In this study, we isolated a new isoflavanostilbene maackiapicevestitol (1) as a mixture of two stable conformers 1a and 1b as well as five previously known dimeric and monomeric stilbens: piceatannol (2), maackin (3), scirpusin A (4), maackiasine (5), and maackolin (6) from M. amurensis heartwood, using column chromatography on polyamide, silicagel, and C-18. The structures of these compounds were elucidated by NMR, HR-MS, and CD techniques. Maksar® obtained from M. amurensis heartwood and polyphenolics 1-6 possessed moderate anti-HSV-1 activity in cytopathic effect (CPE) inhibition and RT-PCR assays. A model of PQ-induced neurotoxicity was used to study the neuroprotective potential of polyphenolic compounds from M. amurensis. Maksar® showed the highest neuroprotective activity and increased cell viability by 18% at a concentration of 10 µg/mL. Maackolin (6) also effectively increased the viability of PQ-treated Neuro-2a cells and the value of mitochondrial membrane potential at concentrations up to 10 µΜ. Maksar® and compounds 1-6 possessed higher FRAP and DPPH-scavenging effects than quercetin. However, only compounds 1 and 4 at concentrations of 10 µM as well as Maksar® (10 µg/mL) statistically significantly reduced the level of intracellular ROS in PQ-treated Neuro-2a cells.

The Potential Value of Debarking Water as a Source of Polyphenolic Compounds for the Specialty Chemicals Sector.

Forest-based industries produce huge quantities of bark during their primary processing activities. In Nordic pulp and paper industries, where a wet debarking process is used for bark removal, toxic debarking water and bark press water are produced as a by-product. However, polyphenols represent an important fraction of the debarking water and bark press water. These polyphenolic compounds are of commercial interest in chemical specialty sectors since polyphenols have been proven to have diverse health benefits, and after collecting them from waste sources, they can act as alternatives to oil-based chemicals. Determining the economic potential of polyphenolic compounds, identifying their molecular structure, and determining the antioxidant capacity of these compounds present in debarking water and bark can support the identification of their potential applications. The results show that water extractions from bark have a lower efficiency than (partial) alcoholic extractions. Nevertheless, a considerable amount of low-molecular polyphenolic compounds, which are of interest for high-end applications, was found in all extracts. Bark press water has a highly versatile range of polyphenolic compounds and showed some antioxidant activity, making it a great source for the collection of polyphenolic compounds, in contrast to debarking water, which had a much lower polyphenolic content and low antioxidant activity.

Chemical Composition, Antioxidant Activity and Cytocompatibility of Polyphenolic Compounds Extracted from Food Industry Apple Waste: Potential in Biomedical Application.

Apple pomace (AP) from the food industry is a mixture of different fractions containing bioactive polyphenolic compounds. This study provides a systematic approach toward the recovery and evaluation of the physiochemical and biological properties of polyphenolic compounds from AP. We studied subcritical water extraction (SCW) and solvent extraction with ethanol from four different AP fractions of pulp, peel, seed, core, and stem (A), peel (B), seed and core (C), and pulp and peel (D). The subcritical water method at the optimum condition resulted in total polyphenolic compounds (TPC) of 39.08 ± 1.10 mg GAE per g of AP on a dry basis compared to the ethanol extraction with TPC content of 10.78 ± 0.94 mg GAE/g db. Phloridzin, chlorogenic acid, and quercetin were the main identified polyphenolics in the AP fractions using HPLC. DPPH radical scavenging activity of fraction B and subcritical water (SW) extracts showed comparable activity to ascorbic acid while all ethanolic extracts were cytocompatible toward human fibroblast (3T3-L1) and salivary gland acinar cells (NS-SV-AC). Our results indicated that AP is a rich source of polyphenolics with the potential for biomedical applications.

Possibility to use the different sizes and colors of carrots for the production of juices - comparison of bioactive compounds, nutritional quality, pro-health properties, and sensory evaluation.

BACKGROUND: Carrot is a popular vegetable consumed by people of all age groups and is used in various food products because of its high nutritional content, especially vitamin A. RESULTS: In the present study, colorful fresh carrot juices of 12 carrot varieties were investigated for in vitro antidiabetic, anti-aging, and anti-obesity activities with antioxidant potential by ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and FRAP (ferric reducing ability of plasma) assays. The studied juices were also compared for physicochemical characteristics: titratable acidity, pH, pectin content, total soluble solids, dry mass, ash, viscosity, turbidity, osmolality, and color. The results of the study showed that normal purple carrot juice exhibited the best activities in all biological and antioxidant tests, except for anti-α-glucosidase activity. Normal purple carrot juice also had the highest total mineral content with elevated results for titratable acidity, pH, total soluble solids, dry mass, ash, viscosity, and osmolality. CONCLUSION: Purple carrot juices demonstrated elevated health-promoting activities and could be used in blended beverage recipes to attract children's attention. The results of sensorial characteristics (appearance, color, and taste) of juices, however, showed that people are more familiar with orange carrot products. © 2022 Society of Chemical Industry.

Effect of the type of acetic fermentation process on the chemical composition of prickly pear vinegar (Opuntia ficus-indica).

BACKGROUND: In several countries, the cactus plant (Opuntia ficus-indica (L). Mill.) has received renewed attention because of its ecological, socio-economic and environmental role. In this study, prickly pear vinegar was produced employing two types of acetification processes: surface and submerged culture. Both acetification processes were performed at different temperatures (30, 37, 40 °C) by using two different species of thermotolerant acetic acid bacteria (Acetobacter malorum and Gluconobacter oxydans). Polyphenols and volatile compounds analyzed by ultra-performance liquid chromatography with diode array detection and stir bar sorptive extraction-gas chromatography-mass spectrometry, respectively, were considered as the main variables to determine the effect of the acetification process on the quality of the vinegar. RESULTS: As a result, 15 polyphenols and 70 volatile compounds were identified and quantified in the vinegar samples produced by both acetification processes. The results showed that the surface acetification method led to an increase in the concentration of phenolic components, which was higher than that in the submerged process. However, a significant increase in volatile compounds predominated by esters and acids was observed when submerged culture acetification was employed, whereas alcohols were predominant in surface culture vinegars. Moreover, multivariate statistical analysis showed that the components that mostly contributed to the differentiation between all vinegar samples were the volatile compounds. CONCLUSION: It has been proved that prickly pear vinegar could be successfully produced at higher temperatures than usual, by employing thermotolerant bacteria, and that the type of acetification method significantly affects the final quality of the vinegar produced. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Binding of Iron (II) Ions by Aqueous Extractions from Yerba Mate (Ilex paraguariensis).

We studied the ability of an aqueous extract from yerba mate and a dry extract obtained on the basis of this aqueous extract to remove Fe(II) ions from an aqueous medium. Aqueous extracts from mate dose-dependently reduced the concentration of free Fe(II) ions assayed by the reaction with 1,10-phenanthroline. This can be attributed to polyphenolic compounds with iron-chelating properties present in aqueous extracts from mate, namely quercetin, rutin, caffeic and chlorogenic acids. These substances effectively removed Fe(II) ions from the medium (the initial concentration of these ions was 15 µM) in the concentration range of 20-30 µM. Binding of Fe(II) ions by aqueous mate extracts (due to the formation of chelate complexes with the participation of polyphenolic compounds) modified their absorption spectra in the visible region. Binding of Fe(II) ions can be a mechanism of the antioxidant action of yerba mate.