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1.
J Agric Food Chem ; 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38602372

RESUMO

Peptide-based self-assembled nanostructures are emerging vehicles for nutrient delivery and interface engineering. The present study screened eight ß-lactoglobulin (ß-Lg) derived peptides and found that two reducing peptides [EQSLVCQCLV (EV-10) and VCQCLVR (VR-7)] demonstrated pH-dependent reversible fibrilization. EV-10 formed fibrils at pH 2.0 but became unordered aggregates at pH 7.0. VR-7 showed the opposite trend. Both peptides could undergo repetitive transitions between fibrils and unordered aggregates during consecutive pH-cycling. Fibrilization of both peptides was dominated by charges carried by N- and C-terminals. Both fibrils were characterized by a cross-ß sheet structure where the ß-sheet was arranged in an antiparallel manner. Fe3+ was reduced by Cys and EV-10 (pH 5.0 and 7.0) simultaneously upon mixing. In contrast, EV-10 fibrils released Fe3+ reducing capacity progressively, which were beneficial to long-term protection Fe2+. The EV-10 fibrils remained intact after simulated gastric digestion and finally dissociated after intestinal digestion. The results shed light on the mechanisms of fibrilization of ß-Lg derived peptides. This study was beneficial to the rational design of smart pH-responsive materials for drug delivery and antioxidants for nutrients susceptible to oxidation.

2.
Carbohydr Polym ; 314: 120965, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37173007

RESUMO

Over the last years, polysaccharides have been linked to antioxidant effects using both in vitro chemical and biological models. The reported structures, claimed to act as antioxidants, comprise chitosan, pectic polysaccharides, glucans, mannoproteins, alginates, fucoidans, and many others of all type of biological sources. The structural features linked to the antioxidant action include the polysaccharide charge, molecular weight, and the occurrence of non-carbohydrate substituents. The establishment of structure/function relationships can be, however, biased by secondary phenomena that tailor polysaccharides behavior in antioxidant systems. In this sense, this review confronts some basic concepts of polysaccharides chemistry with the current claim of carbohydrates as antioxidants. It critically discusses how the fine structure and properties of polysaccharides can define polysaccharides as antioxidants. Polysaccharides antioxidant action is highly dependent on their solubility, sugar ring structure, molecular weight, occurrence of positive or negatively charged groups, protein moieties and covalently linked phenolic compounds. However, the occurrence of phenolic compounds and protein as contaminants leads to misleading results in methodologies often used for screening and characterization purposes, as well as in vivo models. Despite falling in the concept of antioxidants, the role of polysaccharides must be well defined according with the matrices where they are involved.


Assuntos
Antioxidantes , Polissacarídeos , Antioxidantes/farmacologia , Antioxidantes/química , Polissacarídeos/farmacologia , Polissacarídeos/química , Glucanos , Pectinas , Relação Estrutura-Atividade
3.
Antioxidants (Basel) ; 12(2)2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36829805

RESUMO

The present study evaluates the chemical compositions and antioxidant and antipathogenic properties of commercial orange (Citrus sinensis (L.) Osbeck) essential oils obtained using the cold-press method (EOP) and the cold-press method followed by steam distillation (EOPD). The chemical compositions of the volatilizable fractions, determined by gas chromatography-mass spectrometry, were similar in both samples. A relatively large amount of γ-terpinene was found in the EOPD (1.75%) as compared to the EOP (0.84%). Monoterpene hydrocarbons with limonene (90.4-89.8%) followed by myrcene (3.2-3.1%) as the main compounds comprised the principal phytochemical group. The non-volatile phenolics were eight times higher in the EOP than in the EOPD. Several assays with different specificity levels were used to study the antioxidant activity. Although both essential oils presented similar reducing capacities, the radical elimination ability was higher for the EOP. Regarding the antipathogenic properties, the EOs inhibited the biomass and cell viability of Staphylococcus aureus and Pseudomonas aeruginosa biofilms. Furthermore, both EOs similarly attenuated the production of elastase, pyocyanin, and quorum-sensing autoinducers as assessed using Gram-negative bacteria. The EOP and EOPD showed important antioxidant and antipathogenic properties, so they could represent natural alternatives to extend the shelf life of food products by preventing oxidation and contamination caused by microbial spoilage.

4.
Pharmacol Rep ; 75(2): 490-497, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36719636

RESUMO

BACKGROUND: Necroptosis inhibitors, including necrostatin-1 (Nec-1), are attracting attention as potential therapeutic agents against various diseases, such as acute lung injury, chronic obstructive pulmonary disease, acute kidney injury, nonalcoholic fatty liver, and neurodegenerative disease, where necroptosis is thought to act as a contributing factor. Nec-1 suppresses necroptosis by inhibiting receptor-interacting protein (RIP) 1 kinase and can also reduce reactive oxygen species (ROS) production; however, the underlying molecular mechanisms mediating ROS reduction remain unclear. METHODS: The antioxidant effects of necroptosis inhibitors, including Nec-1 and apoptosis inhibitors, were quantified by performing a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Nec-1-related compounds were subsequently assayed for cupric ion-reducing capacity and superoxide dismutase (SOD)-like activity. RESULTS: Considering all examined apoptosis and necroptosis inhibitors, Nec-1and Nec-1i exhibited antioxidant activity in DPPH radical scavenging assay. In the cupric ion-reducing capacity assay, Nec-1i showed stronger antioxidant capacity than Nec-1. In the SOD-like activity assay, both Nec-1 and Nec-1i were found to have stronger antioxidant capacity than ascorbic acid (IC50 = 4.6 ± 0.040 and 61 ± 0.54 µM, respectively). CONCLUSION: These results suggest that Nec-1 and Nec-1i may exhibit direct radical scavenging ability against superoxide anions, independent of RIP1 inhibition.


Assuntos
Antioxidantes , Doenças Neurodegenerativas , Humanos , Antioxidantes/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Necroptose , Apoptose
5.
J Environ Manage ; 319: 115701, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35834848

RESUMO

Surface runoff decrease (SRD) and sediment concentration change (SCC) are accountable for sediment reduction by anti-erosion strategies. Using a design of horizontal stages, contour trenches, fish-scale pits, as well as their combinations, this study evaluated the two components for sediment reduction after the implementation of various land management strategies on steep spoil tips. The study highlighted the interactions between SRD and SCC in reducing sediment, and characterized the temporal variations of sediment-reducing capacity by SRD and SCC. Results showed that slope erosion was well controlled with control ratios of sediment yield ranging from 0.4 to 0.59, 0.2 to 0.22, for horizontal stage- and contour trench-based strategies, respectively. Sediment-reducing benefit by SRD accounted for 52%-77% of the total sediment reduction and highly determined the performance of SCC. Quadratic relationships between sediment-reducing capacity by SCC and that by SRD were observed. The function of SCC only operated when the sediment-reducing capacity by SRD reached a certain threshold. These thresholds varied greatly in the range of 0.75 kg m-3-0.91 kg m-3 and 0.61 kg m-3-0.66 kg m-3 for horizontal stage- and contour trench-based strategies, respectively. The upper limits for sediment-reducing capacity by SCC varied in the range of 0.32 kg m-3-0.44 kg m-3 and 0.63 kg m-3-0.76 kg m-3 for horizontal stage- and contour trench-based strategies, respectively. An efficiency coefficient of 55% and an M-N ratio of 1:1 indicated that sediment-reducing benefits by SRD and SCC were effectively exerted by combining contour trenches and fish-scale pits. The findings emphasized that the application of land management strategies must be considered based on particular goals to restore spoil tips. In practice, if targeted to enhancing sediment-reducing efficiency, contour trenches and fish-scale pits should be primarily considered. However, if the aim is to decrease water consumed for sediment control, then horizontal stages should be principally considered.


Assuntos
Solo , Água , China , Conservação dos Recursos Naturais/métodos , Monitoramento Ambiental , Sedimentos Geológicos
6.
Antioxidants (Basel) ; 11(8)2022 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-35892640

RESUMO

The most interesting activities associated with bread components such as phenolic compounds, fibre, tocols, or newly formed compounds in the Maillard reaction, are their reducing properties responsible for the formation of the overall reducing capacity of bread. Among the electrochemical methods, the cyclic voltammetry (CV) technique has been recently adapted for this purpose. In this study, the application of the CV assay for the determination of the total reducing capacity of flours, doughs, and breads as well as their crumbs and crusts, originated from wheat, spelt, and rye formulated on white flours (extraction rate of 70%) and dark flours (extraction rate of 100%) and baked at 200 °C for 35 min and at 240 °C for 30 min was addressed. The reducing capacity of hydrophilic extracts from white flours and breads as well as their crumbs and crusts showed double values when compared to that of lipophilic ones whilst hydrophilic and lipophilic extracts from dark breads and their parts revealed comparable levels. The dark wheat, spelt, and rye breads showed an approximately threefold higher total reducing capacity than white breads. Baking at higher temperature slightly increased the total reducing capacity of breads and the highest value was found for dark rye bread as well as its crust baked at 240 °C for 30 min. The cyclic voltammetry methodology showed to be especially suitable for screening the bread technology and allows for obtaining rapid electrochemical profiles of bread samples.

7.
J Environ Manage ; 310: 114793, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35220098

RESUMO

Redox reactions between humic substances and Fe(III) compounds play a critical role in the biogeochemical cycle of pollutants. Most humic substances in soils and sediments are in a solid form (i.e. humin (HM)). In order to assess the contribution of electron shuttling via HM within the electron transfer network in natural environments and to predict environmental fate of pollutants associated with iron oxides, it is necessary to understand the electron transfer processes from HM to the environmentally relevant Fe(III) minerals, and to examine the redox reversibility of HM. The results of this study demonstrated that non-reduced HMs could only donate electrons to dissolved ferric citrate and poorly crystalline ferrihydrite, but reduced HMs could also reduce hematite and magnetite that had high crystallinity. The degree of reduction depended on the difference in redox potential and the crystallinity of the Fe(III) compounds. The electron-accepting capacities of different HMs correlated well with their organic carbon content, and quinones and Fe-bound organic component were important electron-accepting groups in HMs. Furthermore, the redox reversibility experiments demonstrated that HMs could maintain stable electron transfer capacities over three reduction-oxidation cycles, indicating that the HM could be an environmentally sustainable electron shuttle. Our results suggest that (1) HM may play an unrecognized and important role in biogeochemical cycles of pollutants in Fe(III) mineral-rich environments; (2) electron shuttling through HM to ferric citrate and ferrihydrite can occur even in the presence of O2; and (3) HM would be a promising material for environmental remediation.


Assuntos
Compostos Férricos , Substâncias Húmicas , Compostos Férricos/química , Substâncias Húmicas/análise , Ferro , Oxirredução
8.
Antioxidants (Basel) ; 10(5)2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-34065207

RESUMO

Plants produce a diverse array of secondary metabolites that are generally nonessential but facilitate ecological interactions. Fruits, vegetables, seeds and nuts can accumulate bioactive secondary metabolites with health-promoting properties, including the potent antioxidant activities of phenolic compounds. Several in vitro assays have been developed to measure the polyphenol content and antioxidant activity of plant extracts, e.g., the simple and highly popular Folin-Ciocalteu (FC) assay. However, the literature contains a number of different descriptions of the assay and it is unclear whether the assay measures the polyphenol content or reducing capacity of the sample. To determine the influence of phenolic structures on the outcome of the FC assay, we tested phenols representing different subgroups (phenolic acids, flavonols, flavanols, dihydrochalcones and flavanones). We observed different results for each reference substance and subgroup. Accordingly, we concluded that the FC assay does not measure the polyphenol content of a sample but determines its reducing capacity instead. Assigning the substances to five structural classes showed that the FC results depend on the number of fulfilled Bors criteria. If a molecule fulfills none of the Bors criteria, the FC results depend on the number of OH groups. We did not find a correlation with other single electron transfer assays (e.g., ABTS and DPPH assays). Furthermore, the FC assay was compatible with all five subgroups and should be preferred over the DPPH assay, which is specific for extracts rich in dihydrochalcones or flavanones.

9.
Appl Physiol Nutr Metab ; 46(1): 86-89, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32835490

RESUMO

This study tested the hypothesis that exposure to chlorine-sterilised pool water would impair oral nitrate reduction (ONR). ONR was assessed in elite swimmers before and after morning and afternoon pool-based training. Nonswimmers were only assessed in the morning. ONR was similar in swimmers and nonswimmers (P = 1.000) and unchanged before and after morning and afternoon training (P ≥ 0.341). Therefore, exposure to chlorinated pool water does not interfere with ONR. Novelty Exposure to chlorine-sterilised pool water does not impair oral nitrate reduction in elite swimmers.


Assuntos
Atletas/estatística & dados numéricos , Cloro/metabolismo , Boca/metabolismo , Nitratos/metabolismo , Piscinas , Natação , Adulto , Feminino , Humanos , Masculino , Reino Unido , Água/química , Adulto Jovem
10.
Iran J Pharm Res ; 19(1): 436-447, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32922499

RESUMO

The content of polysaccharides in Tuber sinense was investigated by isolation and purification, followed with the further antioxidant studies in total reducing capacity and radical scavenging activities. The crude extract of polysaccharides was purified by dialysis, column chromatography, and High Performance Liquid Chromatography. The main components of monosaccharide (s) and molecular structure of single polysaccharide were studied by using methylation, GC-MS, and NMR analysis. One new water-soluble non-starch polysaccharide (PTS-A with the yield of 0.41%) from T. sinense was purified and identified on structural characteristics for the first time. The characterizations of PTS-A were studied on physicochemical properties, main components of monosaccharide (s) and molecular structure. PTS-A was identified as glucan, only containing D-glucoses with the molecular structure of [→6) α-D-Glcp (1→6) α-D-Glcp (1→]n by methylation analysis and NMR. In the determination of total reducing capacity, their reducing abilities could be listed as vitamin C> PTS-A> crude polysaccharides-3> crude polysaccharides-2> crude polysaccharides-1. All of PTS-A, crude polysaccharides-2 and -3 were relatively good scavenger for 1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1- (2,4,6-trinitrophenyl) hydrazyl radicals with the IC50 of 2.81, 4.17 and 3.44 mg/mL, respectively. Thus, the separation and purification of polysaccharides were significant to increase the antioxidant activity in some degree. One new water-soluble 1,6-α-ᴅ-dextran was discovered with the polysaccharide structure identified for the first time. Both PTS-A and crude extracts of polysaccharide performed a potent potential on antioxidant activities. The bioactivities of PTS-A should be generalized to the broader pharmacological effects.

11.
MethodsX ; 7: 100995, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760660

RESUMO

Most of the commonly applied assays used to assess antioxidant properties of plant extracts exploit the ability of some biologically active metabolites to participate in oxidation-reduction reactions with metal ions. On the other hand, most plants contain different chelated metal ions whose levels depend on the geographic origin, soil, and environmental pollutions. In this study the levels of redox-active metal ions in three plant sources were measured and extracts of these botanicals were treated with ChelexⓇ - an ion exchanger that is noteworthy for its ability to bind transition metal ions. The original and chelated extracts were subjected to three antioxidant assays based on single electron transfer. The results obtained showed statistically significant differences between the original and Chelex-treated extracts suggesting that the naturally present metal ions could interfere with the results of the three most commonly applied antioxidant methods.•The proposed pre-analytical procedure is simple and does not require special instrumental equipment.•Preliminary depletion of redox active metal ions, namely iron and copper ions could improve reproducibility of the analytical methods.•The method allows a more reliable comparison of antioxidant properties of particular botanical species from different geographic regions.

12.
Foods ; 9(8)2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32784944

RESUMO

Mushroom irradiation has been considered a sustainable process to generate high amounts of vitamin D2 due to the role of this vitamin for human health and of the global concerns regarding its deficient or inadequate intake. Mushrooms are also receiving increasing interest due to their nutritional and medicinal properties. However, there is still a knowledge gap regarding the effect of UV irradiation on mushroom bioactive compounds. In this study, two of the most cultivated mushroom species worldwide, Agaricus bisporus and Pleurotus ostreatus, were irradiated with UV-B, and the effect of processing was investigated on the contents of vitamin D2 as well as on antioxidant and antiglycation activities. UV irradiation increased vitamin D2 up to 57 µg/g d.w, which is an adequate level for the fortification of a number of target foods. UV irradiation decreased the antioxidant activity when measured by the Folin-Ciocalteu reagent, the 2,2-diphenyl-1-(2,4,6 trinitrophenyl) hydrazyl radical assay and the ferric ion-reducing antioxidant power assay, but did not decrease the mushroom's ability to inhibit glycation of a target protein. These results open up a new area of investigation aimed at selecting mushroom species with high nutraceutical benefits for irradiation in order to maintain their potential properties to inhibit oxidative and glycation processes responsible for human diseases.

13.
J Environ Sci (China) ; 90: 146-156, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32081311

RESUMO

Soil dissolved organic matter (DOM) plays an essential role in the Three Gorges Reservoir (TGR) as a linkage between terrestrial and aquatic systems. In particular, the reducing capacities of soil DOM influence the geochemistry of contaminants such as mercury (Hg). However, few studies have investigated the molecular information of soil DOM and its relationship with relevant geochemical reactivities, including redox properties. We collected samples from eight sites in the TGR areas and studied the link between the molecular characteristics of DOM and their electron donation capacities (EDCs) toward Hg(II). The average kinetic rate and EDC of soil DOM in TGR areas were (0.004 ± 0.001) hr-1 and (2.88 ± 1.39) nmol e-/mg DOMbulk, respectively. Results suggest that higher EDCs and relatively rapid kinetics were related to the greater electron donating components of lignin-derived and perhaps pyrogenic DOM, which are the aromatic constituents that influenced the reducing capacities of DOM in the present study. Molecular details revealed that even the typical autochthonous markers are important for the EDCs of DOM as well, in contrast to what is generally assumed. More studies identifying specific DOM molecular components involved in the abiotic reduction of Hg(II) are required to further understand the relations between DOM sources and their redox roles in the environmental fate of contaminants.


Assuntos
Mercúrio , Compostos Orgânicos/química , Solo , China , Elétrons , Monitoramento Ambiental , Modelos Químicos
14.
Meat Sci ; 163: 108078, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32044653

RESUMO

This study evaluated the use of gamma irradiation (3, 6 and 9 kGy) in frozen vacuum-packed beef and subsequent thawing and aging for up to 14 days. The effects on tenderness, color, and oxidative properties were determined and compared to non-irradiated controls for frozen/thawed and chilled vacuum-packed beef. The combined irradiation and freezing/thawing processes increased total exudate loss and reduced the meat water-holding capacity, regardless of the dose used. Myofibrillar fragmentation was favored by the freezing/thawing processes and negatively affected by irradiation. Lower shear force values were observed in the non-irradiated frozen/thawed samples. Frozen samples irradiated at 9 kGy had a higher percentage of soluble collagen, lipid peroxidation, and a more reddish color tone. The meat reducing capacity and oxygen consumption were reduced by freezing and further by irradiation, which also included accumulation of metmyoglobin. It was concluded that irradiation of frozen meat and its subsequent thawing and aging does not confer any additional advantages for beef technological quality.


Assuntos
Congelamento , Carne Vermelha/análise , Carne Vermelha/efeitos da radiação , Animais , Bovinos , Cor , Manipulação de Alimentos/métodos , Raios gama , Metamioglobina , Músculo Esquelético , Oxirredução , Resistência ao Cisalhamento/efeitos da radiação , Vácuo , Água/química
15.
Water Res ; 169: 115217, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31675608

RESUMO

The reducing capacity (RC) of natural organic matter plays an important role in the carbon cycle and biogeochemical fates of environmental contaminants in the aquatic system. However, the electron donation potentials of dissolved organic matter (DOM) from high-latitude lakes are still uncertain. In this study, we collected DOM samples from high-latitude lakes across the Arctic and boreal regions in Sweden and Norway to investigate the effects of the DOM concentration and characteristics on its ambient reducing capacity (ARC). Mercury (Hg(II)) abiotic reduction in darkness was used to determine the ARC. The results showed that the DOM in Arctic lakes is less terrestrial-dominant than in reference sites (i.e., forest lakes). Between the two categories of Arctic lakes, tundra lakes are more terrestrial-influenced compared to mountain lakes. Additionally, terrestrial-originated DOM is a main controlling factor for enhancing the ambient reducing capacity, whereas the DOM concentration, i.e., dissolved organic carbon (DOC), resulted in variations in the Hg/DOC ratios that also cause the variations of the observed ARC values. Thus, comparisons of the ARC values can be conducted while oxidant/DOC ratios are kept the same and reported through the method using heavy metals as a chemical probe. After correction for Hg/DOC ratio interference, the ambient reducing capacity of DOM followed the order: boreal forest lakes > Arctic tundra lakes > Arctic mountain lakes. This study highlights that the DOM concentration should also be considered when estimating the ARC as compared to the previous that mainly focusing on the properties of DOM such as its origins. As climate change is projected to be severe in high latitudes, this study demonstrates a significant connection between aquatic DOM geochemical reactivity and terrestrial inputs, which is crucial for a better prediction of the role of DOM in high-latitude lakes in the context of climate change.


Assuntos
Lagos , Mercúrio , Carbono , Noruega , Suécia
16.
Food Chem ; 275: 644-660, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30724245

RESUMO

Food products containing lipids, especially unsaturated fatty acids, are prone to oxidation reactions, which lead to the formation of off-flavor, due to side-reaction products that potentially have toxic effects and reduce shelf-life. The Maillard reaction products (MRPs) are widely produced in foods containing reducing sugars and amino-bearing compounds during thermal processing and storage. MRPs possess excellent antioxidant ability in many food products, through chelation of metal ions, breakdown of radical chains and hydrogen peroxide, and scavenging of reactive oxygen species. This review presents an overview of the antioxidant activity of MRPs in model and real food systems. It also provides the pros and cons of the Maillard reaction, some available antioxidant assays to evaluate the antioxidative ability of MRPs, and parameters influencing their functional properties. In addition, metal chelation-based antibrowning ability of MRPs to inhibit the enzymatic browning reaction in fruits and vegetables is discussed.


Assuntos
Antioxidantes/química , Análise de Alimentos , Modelos Teóricos , Quelantes/química , Reação de Maillard , Oxirredução , Oxirredutases/metabolismo , Espécies Reativas de Oxigênio/química
17.
Sci Total Environ ; 643: 486-495, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29945084

RESUMO

In this study, hydrochar was prepared from wheat straw (WS) and Spartina alterniflora (SA) biomass by hydrothermal carbonization, and further treated with HCl and NaOH washing, HNO3 oxidization and low temperature thermal heating. The reducing capacity (RC) of sample was quantified by I2 titration to explore how these modification methods affected the redox properties of hydrochar. The results indicated HNO3 and thermal oxidization increased the RC of hydrochar by 2-5 folds while NaOH washing had the negative effect on samples' RC. By analyzing the excitation-emission matrix (EEM) fluorescence of alkaline extraction solution of sample, humic acid like substances generated from various methods were identified as one of the major sources for electron donating. HNO3 oxidization could significantly increase the RC in hydrochar, which was likely resulting from the generation of alkali-soluble small molecule organic compounds. However, excessive oxidation by nitric acid with prolonged duration led to the gradual decrease in hydrochar's RC. Heating treatment caused a significant increase in the content of redox-active oxygen-containing functional groups and persistent free radicals (PFRs) in hydrochar. Even though both could donate electrons in the redox reaction with I2, the former was considered a greater contributor for the RC of hydrochar. From this study, the origin of RC of hydrochar can be identified as: oxygen-containing functionality, humic-like matter and PFRs. By employing different modification methods, the RC of hydrochar could be tuned by regulating the above sources. This study provided fundamental knowledges and simple routes to manipulate the redox properties of hydrochar for different environmental applications.


Assuntos
Biomassa , Carbono/química , Modelos Químicos , Oxirredução , Poaceae , Triticum
18.
J Food Sci Technol ; 55(4): 1331-1338, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29606747

RESUMO

An alternative method for quantification of the total reducing capacity (TRC) of processed ready-to-drink fruit juices (orange, grape, peach, mango, cashew, strawberry, apple and guava) is suggested. The spectrophotometric procedure is based on the reduction of Cu(II) to Cu(I) by antioxidants (present in the samples) in aqueous buffered solution (pH 7.0), containing 4,4'-dicarboxy-2,2'-biquinoline acid (H2BCA), yielding the [Formula: see text] complexes. The absorbance values at 558 nm (A558 nm) of the [Formula: see text] complexes obtained with juice samples were compared with A558 nm values of the same complexes obtained with a standard ascorbic acid solution and used to quantify and express the reducing capacity of each sample. Regarding orange juices a positive relationship between the TRC values using the [Formula: see text] complexes and the labelled ascorbic acid (AA) content along with the total polyphenol content (TPC) was measured. Grape juices showed the best positive correlation was verified between the TRC (with the [Formula: see text] complexes) and the TPC. While other fruit juices showed good agreement of TRC values with [Formula: see text] complexes and DPPH reagent. The proposed method may be applied to measure the TRC of beers and wines and also for biological samples like serum and follicular fluid.

19.
Eur J Med Chem ; 151: 272-284, 2018 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-29626799

RESUMO

Obesity is an increasing epidemic worldwide and novel treatments are urgently needed. Polyphenols are natural compounds derived from plants, which are known in particular for their antioxidant properties. However, some polyphenols were described to possess anti-obesity activities in vitro and in vivo. In this study, we aimed to screen a library of 85 polyphenol derivatives for their lipid reducing activity and toxicity. Compounds were analyzed at 5 µM with the zebrafish Nile red fluorescence fat metabolism assay and for general toxicity in vivo. To improve the safety profile, compounds were screened at 50 µM in murine preadipocytes in vitro for cytotoxicity. Obtained activity data were used to create a 2D-QSAR (quantitative structure activity relationship) model. 38 polyphenols showed strong lipid reducing activity. Toxicity analysis revealed that 18 of them did not show any toxicity in vitro or in vivo. QSAR analysis revealed the importance of the number of rings, fractional partial positively charged surface area, relative positive charge, relative number of oxygen atoms, and partial negative surface area for lipid-reducing activity. The five most potent compounds with EC50 values in the nanomolar range for lipid reducing activity and without any toxic effects are strong candidates for future research and development into anti-obesity drugs. Molecular profiling for fasn, sirt1, mtp and ppary revealed one compound that reduced significantly fasn mRNA expression.


Assuntos
Fármacos Antiobesidade/farmacologia , Antioxidantes/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Polifenóis/farmacologia , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Fármacos Antiobesidade/química , Fármacos Antiobesidade/toxicidade , Antioxidantes/química , Antioxidantes/toxicidade , Avaliação Pré-Clínica de Medicamentos , Camundongos , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Polifenóis/química , Polifenóis/toxicidade , Peixe-Zebra
20.
Food Chem ; 239: 323-332, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-28873576

RESUMO

Rapeseed pomace (RSP) is a waste product obtained after edible oil production from Brassica napus. Analysis of ubiquitous secondary metabolites in RSP samples (two breeds, harvested in 2012/2014 respectively from North East of Scotland) and their ethanol/water (95:5) Soxhlet extracts were carried out. Soxhlet extraction of the RSP (petroleum ether followed by 95% ethanol) gave a solid extract. LC-MS/MS data of the extracts revealed several secondary metabolites, with Sinapic acid being the most abundant. Strong antioxidant activities of the Soxhlet extracts were confirmed from the results obtained in the FRAP, DPPH and ORAC assays. Furthermore, for the very first time, RSP extracts (13.9µg/ml) provided complete DNA protection, from oxidative stress induced by AAPH (3.5mM). Therefore the strong antioxidant and DNA protecting properties demonstrated by the RSP extracts in this study warrants further investigation for their revalorisation and potential use as reliable source of antioxidants in different food applications.


Assuntos
Brassica rapa , Antioxidantes , DNA de Plantas , Oxidantes , Extratos Vegetais , Sementes , Espectrometria de Massas em Tandem
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