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1.
Foods ; 13(16)2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39200479

RESUMEN

Developing of functional foods is a promising strategy to reduce the increasing burden of colorectal cancer worldwide. Fruit pomace, particularly polyphenol and anthocyanin-rich chokeberry and blueberry, is a valuable ingredient for functional foods and nutraceuticals. Our study aimed to evaluate the anti-inflammatory and antiproliferative effects of chokeberry and blueberry pomace extracts on C2BBe1 colorectal carcinoma cells and explore the underlying signaling pathways. We analyzed both pomace extracts for total polyphenols and anthocyanins using Folin-Ciocalteu method and ultra-performance liquid chromatography, while antioxidative activity was assessed via the 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. We evaluated the in vitro anti-inflammatory and antiproliferative effects using trypan blue exclusion, MTT and LDH assays, and assessed protein levels of p-Erk1/2, Akt-1, STAT1, STAT3, occludin, oxidized proteins, and MDA-protein adducts through western blotting, as well as analysis of a 37-plex panel of inflammatory markers. Chokeberry extracts exhibited higher total polyphenol content, anthocyanin levels, and antioxidative activity compared to blueberry extracts, however, blueberry extracts effects on cell viability and proliferation in C2BBe1 cells were stronger. Both fruit pomaces induced non-inflammatory cell death characterized by membrane integrity loss, beneficial in cancer therapy. Our data suggests chokeberry's cytotoxicity may be mediated by Erk signaling and Akt-1 inhibition, while blueberry uniquely decreased occludin levels. These berries pomaces' potential to mitigate cancer risks and enhance treatment efficacy is promising, warranting further investigation for functional foods development.

2.
Eur J Med Chem ; 265: 116075, 2024 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-38150963

RESUMEN

The immune response encompasses innate and adaptive immunity, each with distinct and specific activities. The innate immune system is constituted by phagocytic cells, macrophages, monocytes and neutrophils, the cascade system, and different classes of receptors such as toll-like receptors that are exploited by the innate immune cells. The adaptive immune system is antigen-specific, encompassing memory lymphocytes and the corresponding specific receptors. Inflammation is understood as an activation of different signaling pathways such as toll-like receptors or nuclear factor kappa-light-chain-enhancer of activated B cells, with an increase in nitric oxide, inflammatory cytokines and chemokines. Increased oxidative stress has been identified as main source of chronic inflammation. Phenolic antioxidants modulate the activities of lymphocytes and macrophages by impacting cytokines and nitric oxide release, exerting anti-inflammatory effect. The nuclear-factor kappa-light-chain-enhancer of activated B cells signaling pathway and the mitogen-activated protein kinase pathway are targeted, alongside an increase in nuclear factor erythroid 2-related factor mediated antioxidant response, triggering the activity of antioxidant enzymes. The inhibitive potential on phospholipase A2, cyclooxygenase and lipoxygenase in the arachidonic acid pathway, and the subsequent reduction in prostaglandin and leukotriene generation, reveals the potential of phenolics as inflammation antagonists. The immunomodulative potential encompasses the capacity to interfere with proinflammatory cytokine synthesis and with the expression of the corresponding genes. A diet rich in antioxidants can result in prevention of inflammation-related pathologies. More investigations are necessary to establish the role of these antioxidants in therapy. The appropriate delivery system and the prooxidant effects exhibited at large doses, or in the presence of heavy metal cations should be regarded.


Asunto(s)
Antioxidantes , FN-kappa B , Humanos , Antioxidantes/farmacología , Antioxidantes/metabolismo , FN-kappa B/metabolismo , Óxido Nítrico , Antiinflamatorios/farmacología , Citocinas/metabolismo , Inflamación/tratamiento farmacológico , Receptores Toll-Like , Inmunidad , Lipopolisacáridos
3.
Int J Mol Sci ; 25(1)2023 Dec 25.
Artículo en Inglés | MEDLINE | ID: mdl-38203477

RESUMEN

Differentiation of amniotic fluid stem cells (AFSCs) into multiple lineages is controlled by epigenetic modifications, which include DNA methylation, modifications of histones, and the activity of small noncoding RNAs. The present study investigates the role of miRNAs in the differentiation of AFSCs and addresses how their unique signatures contribute to lineage-specific differentiation. The miRNA profile was assessed in AFSCs after 4 weeks of endothelial and muscular differentiation. Our results showed decreased expression of five miRNAs (miR-18a-5p, miR-125b-5p, miR-137, miR-21-5p, and let-7a) and increased expression of twelve miRNAs (miR-134-5p, miR-103a-3p, let-7i-5p, miR-214-3p, let-7c-5p, miR-129-5p, miR-210-3p, let-7d-5p, miR-375, miR-181-5p, miR-125a-5p, and hsa-let-7e-5p) in endothelial progenitor cells (EPCs) compared with undifferentiated AFSCs. AFSC differentiation into smooth muscle revealed notable changes in nine out of the 84 tested miRNAs. Among these, three miRNAs (miR-18a-5p, miR-137, and sa-miR-21-5p) were downregulated, while six miRNAs (miR-155-5p, miR-20a-5p, let-7i-5p, hsa-miR-134-5p, hsa-miR-214-3p, and hsa-miR-375) exhibited upregulation. Insights from miRNA networks promise future advancements in understanding and manipulating endothelial and muscle cell dynamics. This knowledge has the potential to drive innovation in areas like homeostasis, growth, differentiation, and vascular function, leading to breakthroughs in biomedical applications and therapies.


Asunto(s)
MicroARNs , Células Satélite del Músculo Esquelético , Líquido Amniótico , MicroARNs/genética , Músculo Liso , Reacción en Cadena de la Polimerasa
4.
J Med Chem ; 65(19): 12562-12593, 2022 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-36136726

RESUMEN

Viral pathologies encompass activation of pro-oxidative pathways and inflammatory burst. Alleviating overproduction of reactive oxygen species and cytokine storm in COVID-19 is essential to counteract the immunogenic damage in endothelium and alveolar membranes. Antioxidants alleviate oxidative stress, cytokine storm, hyperinflammation, and diminish the risk of organ failure. Direct antiviral roles imply: impact on viral spike protein, interference with the ACE2 receptor, inhibition of dipeptidyl peptidase 4, transmembrane protease serine 2 or furin, and impact on of helicase, papain-like protease, 3-chyomotrypsin like protease, and RNA-dependent RNA polymerase. Prooxidative environment favors conformational changes in the receptor binding domain, promoting the affinity of the spike protein for the host receptor. Viral pathologies imply a vicious cycle, oxidative stress promoting inflammatory responses, and vice versa. The same was noticed with respect to the relationship antioxidant impairment-viral replication. Timing, dosage, pro-oxidative activities, mutual influences, and interference with other antioxidants should be carefully regarded. Deficiency is linked to illness severity.


Asunto(s)
Tratamiento Farmacológico de COVID-19 , SARS-CoV-2 , Enzima Convertidora de Angiotensina 2 , Antiinflamatorios , Antioxidantes/farmacología , Antioxidantes/uso terapéutico , Antivirales/farmacología , Antivirales/uso terapéutico , Síndrome de Liberación de Citoquinas , Dipeptidil Peptidasa 4 , Furina , Humanos , Papaína , ARN Polimerasa Dependiente del ARN , Especies Reactivas de Oxígeno , Serina , Glicoproteína de la Espiga del Coronavirus/metabolismo
5.
Cancers (Basel) ; 14(11)2022 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-35681771

RESUMEN

BACKGROUND: Biomarker profiles should represent a coherent description of the colorectal cancer (CRC) stage and its predicted evolution. METHODS: Using droplet digital PCR, we detected the allelic frequencies (AF) of KRAS, NRAS, BRAF, and EGFR mutations from 60 tumors. We employed a pair-wise association approach to estimate the risk involving AF mutations as outcome variables for clinical data and as predicting variables for tumor-staging. We evaluated correlations between mutations of AFs and also between the mutations and histopathology features (tumor staging, inflammation, differentiation, and invasiveness). RESULTS: KRAS G12/G13 mutations were present in all patients. KRAS Q61 was significantly associated with poor differentiation, high desmoplastic reaction, invasiveness (ypT4), and metastasis (ypM1). NRAS and BRAF were associated with the right-side localization of tumors. Diabetic patients had a higher risk to exhibit NRAS G12/G13 mutations. BRAF and NRAS G12/G13 mutations co-existed in tumors with invasiveness limited to the submucosa. CONCLUSIONS: The associations we found and the mutational AF we reported may help to understand disease processes and may be considered as potential CCR biomarker candidates. In addition, we propose representative mutation panels associated with specific clinical and histopathological features of CRC, as a unique opportunity to refine the degree of personalization of CRC treatment.

6.
Eur J Med Chem ; 232: 114175, 2022 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-35151223

RESUMEN

oxidative stress is caused by an abundant generation of reactive oxygen species, associated to a diminished capacity of the endogenous systems of the organism to counteract them. Activation of pro-oxidative pathways and boosting of inflammatory cytokines are always encountered in viral infections, including SARS-CoV-2. So, the importance of counteracting cytokine storm in COVID-19 pathology is highly important, to hamper the immunogenic damage of the endothelium and alveolar membranes. Antioxidants prevent oxidative processes, by impeding radical species generation. It has been proved that vitamin intake lowers oxidative stress markers, alleviates cytokine storm and has a potential role in reducing disease severity, by lowering pro-inflammatory cytokines, hampering hyperinflammation and organ failure. For the approached compounds, direct antiviral roles are also discussed in this review, as these activities encompass secretion of antiviral peptides, modulation of angiotensin-converting enzyme 2 receptor expression and interaction with spike protein, inactivation of furin protease, or inhibition of pathogen replication by nucleic acid impairment induction. Vitamin administration results in beneficial effects. Nevertheless, timing, dosage and mutual influences of these micronutrients should be carefullly regarded.


Asunto(s)
Antioxidantes , Tratamiento Farmacológico de COVID-19 , Antiinflamatorios , Antioxidantes/farmacología , Antioxidantes/uso terapéutico , Humanos , SARS-CoV-2 , Vitaminas/farmacología , Vitaminas/uso terapéutico
7.
Foods ; 12(1)2022 Dec 25.
Artículo en Inglés | MEDLINE | ID: mdl-36613326

RESUMEN

The risk of mycotoxins co-occurrence in extrusion-produced dry foods increases due to their composition based on various grains and vegetables. This study aimed to validate a risk estimation for the association between ingredients and the ELISA-detected levels of DON, FUM, ZEA, AFs, T2, and OTA in 34 dry dog food products. The main ingredients were corn, beet, and oil of different origins (of equal frequency, 79.41%), rice (67.6%), and wheat (50%). DON and FUM had the strongest positive correlation (0.635, p = 0.001). The presence of corn in the sample composition increased the median DON and ZEA levels, respectively, by 99.45 µg/kg and 65.64 µg/kg, p = 0.011. In addition to DON and ZEA levels, integral corn presence increased the FUM median levels by 886.61 µg/kg, p = 0.005. For corn gluten flour-containing samples, DON, FUM, and ZEA median differences still existed, and OTA levels also differed by 1.99 µg/kg, p < 0.001. Corn gluten flour presence was strongly associated with DON levels > 403.06 µg/kg (OR = 38.4, RR = 9.90, p = 0.002), FUM levels > 1097.56 µg/kg (OR = 5.56, RR = 1.45, p = 0.048), ZEA levels > 136.88 µg/kg (OR = 23.00, RR = 3.09, p = 0.002), and OTA levels > 3.93 µg/kg (OR = 24.00, RR = 3.09, p = 0.002). Our results suggest that some ingredients or combinations should be avoided due to their risk of increasing mycotoxin levels.

8.
Sci Rep ; 11(1): 7940, 2021 04 12.
Artículo en Inglés | MEDLINE | ID: mdl-33846436

RESUMEN

Therapeutic approaches focused on the inflammatory microenvironment are currently gaining more support, as biomolecules involved in the inflammatory colorectal cancer (CRC) tumor microenvironment are being explored. We analyzed tumor and paired normal tissue samples from CRC patients (n = 22) whom underwent tumor resection surgery. We assessed 39 inflammation-involved biomolecules (multiplex magnetic bead-based immunoassay), CEA and CA19-9 (ELISA assay) and the tissue expression levels of occludin and also pErk, STAT1 and STAT3 transcriptional factors (western blot). Tumor staging has been established by histopathological evaluation of HE stained tumor tissue sections. We report 32 biomarkers displaying statistically significant differences in tumor vs. control. Additionally, positive statistical biomarker correlations were found between MMP2-IL8 and BAFF-IL8 (Pearson correlation coefficients > 0.751), while APRIL-MMP2, APRIL-BAFF and APRIL-IL8 were negatively correlated (correlation coefficients < - 0.650). While APRIL, BAFF, IL8 and MMP2 did not modulate with tumor stage, they were inversely related to the immune infiltrate level and CD163 tissue expression. We conclude that the significantly decreased APRIL and increased BAFF, IL8 and MMP2 expression were tumor-specific and deserve consideration in the development of new treatments. Also, the positive correlation between Chitinase 3-like 1 and IL8 (0.57) or MMP2 (0.50) suggest a role in tumor growth and metastasis pathways.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Neoplasias Colorrectales/patología , Inflamación/patología , Microambiente Tumoral , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proteínas de Neoplasias/metabolismo
9.
Eur J Med Chem ; 209: 112891, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33032084

RESUMEN

The present review paper focuses on the chemistry of oxidative stress mitigation by antioxidants. Oxidative stress is understood as a lack of balance between the pro-oxidant and the antioxidant species. Reactive oxygen species in limited amounts are necessary for cell homeostasis and redox signaling. Excessive reactive oxygenated/nitrogenated species production, which counteracts the organism's defense systems, is known as oxidative stress. Sustained attack of endogenous and exogenous ROS results in conformational and oxidative alterations in key biomolecules. Chronic oxidative stress is associated with oxidative modifications occurring in key biomolecules: lipid peroxidation, protein carbonylation, carbonyl (aldehyde/ketone) adduct formation, nitration, sulfoxidation, DNA impairment such strand breaks or nucleobase oxidation. Oxidative stress is tightly linked to the development of cancer, diabetes, neurodegeneration, cardiovascular diseases, rheumatoid arthritis, kidney disease, eye disease. The deleterious action of reactive oxygenated species and their role in the onset and progression of pathologies are discussed. The results of oxidative attack become themselves sources of oxidative stress, becoming part of a vicious cycle that amplifies oxidative impairment. The term antioxidant refers to a compound that is able to impede or retard oxidation, acting at a lower concentration compared to that of the protected substrate. Antioxidant intervention against the radicalic lipid peroxidation can involve different mechanisms. Chain breaking antioxidants are called primary antioxidants, acting by scavenging radical species, converting them into more stable radicals or non-radical species. Secondary antioxidants quench singlet oxygen, decompose peroxides, chelate prooxidative metal ions, inhibit oxidative enzymes. Moreover, four reactivity-based lines of defense have been identified: preventative antioxidants, radical scavengers, repair antioxidants, and those relying on adaptation mechanisms. The specific mechanism of a series of endogenous and exogenous antioxidants in particular aspects of oxidative stress, is detailed. The final section resumes critical conclusions regarding antioxidant supplementation.


Asunto(s)
Antioxidantes/farmacología , Estrés Oxidativo/efectos de los fármacos , Animales , Antioxidantes/química , Antioxidantes/metabolismo , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/metabolismo , Diabetes Mellitus/tratamiento farmacológico , Diabetes Mellitus/metabolismo , Oftalmopatías/tratamiento farmacológico , Oftalmopatías/metabolismo , Humanos , Enfermedades Renales/dietoterapia , Enfermedades Renales/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Enfermedades Neurodegenerativas/tratamiento farmacológico , Enfermedades Neurodegenerativas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Enfermedades Vasculares/tratamiento farmacológico , Enfermedades Vasculares/metabolismo
10.
Beilstein J Org Chem ; 14: 2580-2588, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30410619

RESUMEN

Pseudomonas aeruginosa relies on the quorum sensing (QS) signaling system as a central regulator mechanism of virulence expression that contributes to the formation and maintenance of biofilms and tolerance to conventional antimicrobials. QS Signaling molecules (QSSMs) may be recognized and may function also within the host cells, being potentially involved in the progression of the infectious process. In this study we evaluate the expression of adhesion and inflammatory molecules in endothelial cells treated with P. aeruginosa QSSMs, in order to bring new insights on the mechanisms involved in the interaction of P. aeruginosa with host cells during the infectious process. Endothelial cells were stimulated with 20 µM of main P. aeruginosa QSSMs (OdDHL = N-(3-oxododecanoyl)-L-homoserine lactone, C4HSL = N-butyryl-L-homoserine lactone, PQS = 2-heptyl-3-hydroxy-4(1H)-quinolone and HHQ = 2-heptyl-4-quinolone). Adherence to endothelial cells, inert substratum and biofilm formation was evaluated. The expression of adhesion molecules (VE-cadherin, PECAM-1, ICAM-1, and P-selectin) and inflammatory response molecules (IL-1ß, IL-6, TNFα, TGFß, and eNOS) was assessed by qRT-PCR and flow cytometry. Our results showed that bacterial adherence to inert substratum and biofilm were decreased in the presence of all tested QSSMs. The adherence index of PAO1 laboratory strain to host cells was decreased between 10-40% in the presence of QSSMs, as compared to untreated control. Expression of eukaryotic cells adhesion molecules ICAM-1 and P-selectin was stimulated by QSSMs, whereas VE-cadherin and PECAM-1 levels were increased only by C4HSL. The inflammatory response of endothelial cells was also modulated, as observed by the modified expression of IL-1ß (for C4HSL, PQS and HHQ), IL-6 (for C4HSL and HHQ), TNFα (for C4HSL and HHQ), TGFß, and eNOS factors. Our results demonstrate that the main pseudomonadal QSSMs differentially modulate endothelial cells adhesion and proinflammatory cytokine expression. These observations provide new insights in the mechanisms by which different QSSMs activate endothelial cells and modulate the infectious process, and support the importance of recent studies aiming to develop anti-QS therapeutic strategies to fight against P. aeruginosa infections.

11.
Eur J Med Chem ; 157: 1326-1345, 2018 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-30196058

RESUMEN

Oxidative decay and microbial spoilage are issues of concern, as they constitute threats to human health. Natural antioxidants and antimicrobials hamper the negative impact of synthetic compounds and they need appropriate delivery systems. Different nanostructures can be developed: association colloids-based nanostructures, nanoemulsions, nanoliposomes, nanolaminates, nanofibers, carbon nanotubes, nanocomposites. The main nanoencapsulation techniques applied to antioxidants and antimicrobials are described: association colloid-based nanoincorporation, lipid-based nanoencapsulation techniques, encapsulation techniques based on biologically-derived polymeric nanocarriers, encapsulation techniques based on non-biological polymeric nanocarriers, cyclodextrin incorporation, electrospraying and electrospinning, carbon nanotubes and nanocomposite encapsulation. Several nanoencapsulation methods can be followed by freeze-drying or spray-drying. Protection of bioactive compounds and controlled release are achieved, but the impact of the nanomaterials on human health and on the environment should be considered. The influence of the nanoencapsulation techniques on the antioxidant/antimicrobial activity is discussed. The choice of the appropriate encapsulation method is vital. Bioactivity increase, preservation or decrease, depend on the interactions established between the functional groups of encapsulated compound and the encapsulating nanomaterial.


Asunto(s)
Antibacterianos/farmacología , Antioxidantes/farmacología , Bacterias/efectos de los fármacos , Nanoestructuras/química , Nanotecnología , Animales , Antibacterianos/química , Antioxidantes/química , Humanos
12.
Eur J Med Chem ; 143: 922-935, 2018 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-29227932

RESUMEN

The present paper aims to review the natural food preservatives with antimicrobial properties emphasizing their importance for the future of food manufacturing and consumers' health. The extraction procedures applied to natural antimicrobials will be considered, followed by the description of some natural preservatives' antimicrobial mechanism of action, including (i) membrane rupture with ATP-ase activity inhibition, (ii) leakage of essential biomolecules from the cell, (iii) disruption of the proton motive force and (iiii) enzyme inactivation. Moreover, a provenance-based classification of natural antimicrobials is discussed by considering the sources of origin for the major natural preservative categories: plants, animals, microbes and fungi. As well, the structure influence on the antimicrobial potential is considered. Natural preservatives could also constitute a viable alternative to address the critical problem of microbial resistance, and to hamper the negative side effects of some synthetic compounds, while meeting the requirements for food safety, and exerting no negative impact on nutritional and sensory attributes of foodstuffs.


Asunto(s)
Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Productos Biológicos/farmacología , Conservantes de Alimentos/farmacología , Hongos/efectos de los fármacos , Parásitos/efectos de los fármacos , Animales , Antiinfecciosos/química , Antiinfecciosos/aislamiento & purificación , Productos Biológicos/química , Productos Biológicos/aislamiento & purificación , Conservantes de Alimentos/química , Conservantes de Alimentos/aislamiento & purificación , Humanos , Pruebas de Sensibilidad Microbiana , Pruebas de Sensibilidad Parasitaria
13.
Oxid Med Cell Longev ; 2016: 9130976, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-28044094

RESUMEN

The present paper aims at reviewing and commenting on the analytical methods applied to antioxidant and antioxidant capacity assessment in plant-derived products. Aspects related to oxidative stress, reactive oxidative species' influence on key biomolecules, and antioxidant benefits and modalities of action are discussed. Also, the oxidant-antioxidant balance is critically discussed. The conventional and nonconventional extraction procedures applied prior to analysis are also presented, as the extraction step is of pivotal importance for isolation and concentration of the compound(s) of interest before analysis. Then, the chromatographic, spectrometric, and electrochemical methods for antioxidant and antioxidant capacity determination in plant-derived products are detailed with respect to their principles, characteristics, and specific applications. Peculiarities related to the matrix characteristics and other factors influencing the method's performances are discussed. Health benefits of plants and derived products are described, as indicated in the original source. Finally, critical and conclusive aspects are given when it comes to the choice of a particular extraction procedure and detection method, which should consider the nature of the sample, prevalent antioxidant/antioxidant class, and the mechanism underlying each technique. Advantages and disadvantages are discussed for each method.


Asunto(s)
Antioxidantes/análisis , Fitoquímicos/análisis , Plantas/química , Métodos Analíticos de la Preparación de la Muestra , Antioxidantes/aislamiento & purificación , Extractos Vegetales/química
14.
Eur J Med Chem ; 97: 55-74, 2015 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-25942353

RESUMEN

This Review Article is focused on the action of the reactive oxygenated species in inducing oxidative injury of the lipid membrane components, as well as on the ability of antioxidants (of different structures and sources, and following different mechanisms of action) in fighting against oxidative stress. Oxidative stress is defined as an excessive production of reactive oxygenated species that cannot be counteracted by the action of antioxidants, but also as a perturbation of cell redox balance. Reactive oxygenated/nitrogenated species are represented by superoxide anion radical, hydroxyl, alkoxyl and lipid peroxyl radicals, nitric oxide and peroxynitrite. Oxidative stress determines structure modifications and function modulation in nucleic acids, lipids and proteins. Oxidative degradation of lipids yields malondialdehyde and 4-hydroxynonenal, but also isoprostanes, from unsaturated fatty acids. Protein damage may occur with thiol oxidation, carbonylation, side-chain oxidation, fragmentation, unfolding and misfolding, resulting activity loss. 8-hydroxydeoxyguanosine is an index of DNA damage. The involvement of the reactive oxygenated/nitrogenated species in disease occurrence is described. The unbalance between the oxidant species and the antioxidant defense system may trigger specific factors responsible for oxidative damage in the cell: over-expression of oncogene genes, generation of mutagen compounds, promotion of atherogenic activity, senile plaque occurrence or inflammation. This leads to cancer, neurodegeneration, cardiovascular diseases, diabetes, kidney diseases. The concept of antioxidant is defined, along with a discussion of the existent classification criteria: enzymatic and non-enzymatic, preventative or repair-systems, endogenous and exogenous, primary and secondary, hydrosoluble and liposoluble, natural or synthetic. Primary antioxidants are mainly chain breakers, able to scavenge radical species by hydrogen donation. Secondary antioxidants are singlet oxygen quenchers, peroxide decomposers, metal chelators, oxidative enzyme inhibitors or UV radiation absorbers. The specific mechanism of action of the most important representatives of each antioxidant class (endogenous and exogenous) in preventing or inhibiting particular factors leading to oxidative injury in the cell, is then reviewed. Mutual influences, including synergistic effects are presented and discussed. Prooxidative influences likely to occur, as for instance in the presence of transition metal ions, are also reminded.


Asunto(s)
Estrés Oxidativo , Especies Reactivas de Oxígeno/toxicidad , Antioxidantes/uso terapéutico , Humanos , Modelos Biológicos , Estrés Oxidativo/efectos de los fármacos
15.
Molecules ; 16(2): 1349-65, 2011 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-21285920

RESUMEN

A method was developed for assessing ascorbic acid concentration in fruit juices and wine by differential pulse voltammetry. The oxidation peak for ascorbic acid occurs at about 530 mV (versus SCE) on a Pt strip working electrode and at about 470 mV on a carbon paste working electrode. The influence of the operational parameters like the pulse amplitude and the pulse period on the analytical signal was investigated. The obtained calibration graph shows a linear dependence between the peak height and ascorbic acid concentration within the range 0.31-20 mM with a Pt working electrode, and within the range 0.07-20 mM with a carbon paste working electrode. The equation of the calibration graph was y = 21.839x + 35.726, r² = 0.9940, when a Pt strip electrode was used (where y represents the value of the current intensity measured for the peak height, expressed as µA and x the analyte concentration, as mM). R.S.D. = 2.09%, n = 10, C(ascorbic acid) = 2.5 mM. The equation of the calibration graph was y = 3.4429x + 5.7334, r² = 0.9971, when a carbon paste electrode was used (where y represents the value of intensity measured for the peak height, expressed as µA and x the analyte concentration, as mM). R.S.D. = 2.35%, n = 10, C(ascorbic acid) = 2.5 mM. The developed method was applied to ascorbic acid assessment in fruit juices and wine. The ascorbic acid content determined ranged between 6.83 mg/100 mL juice for soft drinks (Fanta Madness) and 54.74 mg/100 mL for citrus (lemon) juices obtained by squeezing fruit. Different ascorbic acid concentrations (from standard solutions) were added to the analysed samples, the degree of recovery being comprised between 94.74 and 104.97%. The results of ascorbic acid assessment by differential pulse voltammetry were compared with those obtained by cyclic voltammetry. The results obtained by the two methods were in good agreement.


Asunto(s)
Ácido Ascórbico/análisis , Bebidas/análisis , Carbono/química , Electroquímica/métodos , Electrodos , Frutas/química , Vino/análisis , Humanos , Platino (Metal)/química , Potenciometría/métodos
16.
Molecules ; 14(1): 480-93, 2009 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-19158657

RESUMEN

The aim of this paper was to assess the total antioxidant capacity of some commercial fruit juices (namely citrus), spectrophotometrically and by the biamperometric method, using the redox couple DPPH. (2,2-diphenyl-1-picrylhydrazyl)/DPPH (2,2-diphenyl-1-picrylhydrazine). Trolox was chosen as a standard antioxidant. In the case of the spectrophometric method, the absorbance decrease of the DPPH. solution was followed. For the biamperometric method, the influence of some parameters like the potential difference, DeltaE, DPPH. concentration, and Trolox concentration was investigated. The calibration graph obtained for Trolox presents linearity between 5 and 30 microM, (y=0.059 x + 0.0564, where y represents the value of current intensity, expressed as microA and x the value of Trolox concentration, expressed as muM; r(2)=0.9944). The R.S.D. value for the biamperometric method was 1.29% (n=10, c=15 microM Trolox). In the case of the spectrophotometric method, the calibration graph obtained for Trolox presents linearity between 0.01 and 0.125 mM (y= -9.5789 x+1.4533, where y represents the value of absorbance and x, the value of Trolox concentration, expressed as mM; r(2)=0.9963). The R.S.D. value for the spectrophotometric method was 2.05%. Both methods were applied to total antioxidant activity determination in real samples (natural juices and soft drinks) and the results were in good agreement.


Asunto(s)
Antioxidantes/análisis , Bebidas/análisis , Citrus/química , Electroquímica/métodos , Espectrofotometría/métodos , Compuestos de Bifenilo/química , Cromanos/química , Depuradores de Radicales Libres/análisis , Radicales Libres/química , Hidrazinas/química , Estructura Molecular , Oxidación-Reducción , Picratos
17.
J Autom Methods Manag Chem ; 2008: 937651, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-19343183

RESUMEN

A method was developed for assessing ascorbic acid concentration in commercial fruit juice by cyclic voltammetry. The anodic oxidation peak for ascorbic acid occurs at about 490 mV on a Pt disc working electrode (versus SCE). The influence of the potential sweep speed on the peak height was studied. The obtained calibration graph shows a linear dependence between peak height and ascorbic acid concentration in the domain (0.1-10 mmol.L(-1)). The equation of the calibration graph was y = 6.391x + 0.1903 (where y represents the value of intensity measured for the anodic peak height, expressed as muA and x the analyte concentration, as mmol.L(-1), r(2) = 0.9995, r.s.d. = 1.14%, n = 10, C(ascorbic acid) = 2 mmol.L(-1)). The developed method was applied to ascorbic acid assessment in fruit juice. The ascorbic acid content determined ranged from 0.83 to 1.67 mmol.L(-1) for orange juice, from 0.58 to 1.93 mmol.L(-1) for lemon juice, and from 0.46 to 1.84 mmol.L(-1) for grapefruit juice. Different ascorbic acid concentrations (from standard solutions) were added to the analysed samples, the degree of recovery being comprised between 94.35% and 104%. Ascorbic acid determination results obtained by cyclic voltammetry were compared with those obtained by the volumetric method with dichlorophenol indophenol. The results obtained by the two methods were in good agreement.

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