The major objectives of this study were to investigate the antioxidant properties of flaxseed lignans secoisolariciresinol (SECO 2) and secoisolariciresinol diglycoside (SDG 1) and their major oxidative compounds using 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH 47) in an in vitro model of lipid peroxidation. This investigation was facilitated by the structural elucidation of the major oxidative compounds and the ability of flaxseed lignans to delay the onset of oxidation in two model systems. <p>This study showed that SECO 2 oxidation occurs at the aromatic (4-OH) and aliphatic (9-OH) hydroxyl groups. Conversely for SDG 1, only compounds derived from the oxidation of aromatic hydroxyl groups were obtained because the 9-OH position is glucosylated. <p>SECO 2 oxidation with AAPH 47 showed that the intermediate 2a is most likely involved in the generation of early-forming (48 and 52) and 2c for the formation of late-forming (49, 50 and 51) oxidation compounds. Compound 48 is formed from dimerization of 2a that is converted to 52 and then to 51. Compound 50 was formed by the addition of a carbon-centre free radical of AAPH (AP radical) to 2c. Compounds 50 and 51 trap carbon-centered AP radicals supporting SECO 2 as a chain-breaking antioxidant and AAPH 47 as a proper model for study of SECO 2 oxidation in vitro. <p>SDG 1 oxidation with AAPH 47 indicated that intermediates 1b and 1c are most likely involved for the formation of early forming compounds (55 and 58) and 1a leads to the late forming compounds (56 and 57). Compound 55 is a result of dimerization. Compound 56 may be directly formed via intermediate radical 1a by adding AP free radicals. Compound 56 was a stable non-radical compound that could trap AP free radicals, thereby supporting SDG 1 as a chain-breaking antioxidant. Hydrogen abstraction from 4-hydroxyl yielded the radical 1a and hydroxyl radical addition to 1a yielded 57. Compound 58 formed from the addition of OH or H2O to 1c. <p>This study demonstrated that AAPH 47 produces carbon-centred AP radicals upon thermal decomposition and mimics the formation of lipid peroxyl radicals. Interaction of carbon-centred AP radicals with SECO 2 and SDG 1 provides a good model to study the antioxidant reactions of SECO 2 in vitro. p*The relative antioxidant capacity of the flaxseed lignans versus BHT 17, in two model systems, was determined. The stoichiometric ratio for SECO 2 and SDG 1 were 1.5 and 1.1-1.2, respectively, compared to BHT 17 (2.0). The induction time by Rancimat analyzer measured inhibition of autoxidation mediated by flaxseed lignans SECO, SDG and SDG polymer in comparison with BHT 17. The induction time data demonstrated that SECO 2 protected canola oil better than either SDG 1 or SDG polymer 3. <p>These results are important for better understanding about the chemistry behind flaxseed lignan antioxidant activities. This study provided useful evidence that flaxseed lignans can be used as natural antioxidants.

The major objectives of this study were to investigate the antioxidant properties of flaxseed lignans secoisolariciresinol (SECO 2) and secoisolariciresinol diglycoside (SDG 1) and their major oxidative compounds using 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH 47) in an in vitro model of lipid peroxidation. This investigation was facilitated by the structural elucidation of the major oxidative compounds and the ability of flaxseed lignans to delay the onset of oxidation in two model systems. <p>This study showed that SECO 2 oxidation occurs at the aromatic (4-OH) and aliphatic (9-OH) hydroxyl groups. Conversely for SDG 1, only compounds derived from the oxidation of aromatic hydroxyl groups were obtained because the 9-OH position is glucosylated. <p>SECO 2 oxidation with AAPH 47 showed that the intermediate 2a is most likely involved in the generation of early-forming (48 and 52) and 2c for the formation of late-forming (49, 50 and 51) oxidation compounds. Compound 48 is formed from dimerization of 2a that is converted to 52 and then to 51. Compound 50 was formed by the addition of a carbon-centre free radical of AAPH (AP radical) to 2c. Compounds 50 and 51 trap carbon-centered AP radicals supporting SECO 2 as a chain-breaking antioxidant and AAPH 47 as a proper model for study of SECO 2 oxidation in vitro. <p>SDG 1 oxidation with AAPH 47 indicated that intermediates 1b and 1c are most likely involved for the formation of early forming compounds (55 and 58) and 1a leads to the late forming compounds (56 and 57). Compound 55 is a result of dimerization. Compound 56 may be directly formed via intermediate radical 1a by adding AP free radicals. Compound 56 was a stable non-radical compound that could trap AP free radicals, thereby supporting SDG 1 as a chain-breaking antioxidant. Hydrogen abstraction from 4-hydroxyl yielded the radical 1a and hydroxyl radical addition to 1a yielded 57. Compound 58 formed from the addition of OH or H2O to 1c. <p>This study demonstrated that AAPH 47 produces carbon-centred AP radicals upon thermal decomposition and mimics the formation of lipid peroxyl radicals. Interaction of carbon-centred AP radicals with SECO 2 and SDG 1 provides a good model to study the antioxidant reactions of SECO 2 in vitro. p*The relative antioxidant capacity of the flaxseed lignans versus BHT 17, in two model systems, was determined. The stoichiometric ratio for SECO 2 and SDG 1 were 1.5 and 1.1-1.2, respectively, compared to BHT 17 (2.0). The induction time by Rancimat analyzer measured inhibition of autoxidation mediated by flaxseed lignans SECO, SDG and SDG polymer in comparison with BHT 17. The induction time data demonstrated that SECO 2 protected canola oil better than either SDG 1 or SDG polymer 3. <p>These results are important for better understanding about the chemistry behind flaxseed lignan antioxidant activities. This study provided useful evidence that flaxseed lignans can be used as natural antioxidants.

On étudie les effets des nanoparticules (d'argent et de silice) manufacturées sur les métabolismes oxydatifs et inflammatoire. La première partie étudie la toxicité in vivo de l'ingestion de nanoparticules d'argent, pendant 11 semaines, sur un modèle animal - rat Sprague Dawley. Nous y avons mis en évidence l'action toxique des nanoparticules d'argent notamment une hausse de la production d'anion superoxyde par les NADPH oxydases hépatiques et cardiaques, des dyslipidémies, une cytolyse hépatique, une augmentation de cytokines pro-inflammatoires et une tendance à la baisse de l'activité d'enzymes antioxydantes. Ceci nous a conduit à aborder l'étude in vitro, sur des modèles cellulaires intestinaux (Caco-2) et cutanés (HaCaT). Au cours de cette étude, des nanoparticules de silice, fonctionnalisées ou non avec des antioxydants, ont été incubées pendant 24 H en présence des cellules. Nous montrons que la modification de la surface des nanoparticules réduit considérablement leur toxicité en limitant la production d'espèces radicalaires et la mortalité cellulaire. D’autre part, le couplage avec un antioxydant permet d’augmenter la stimulation de voie de signalisation du facteur Nrf2. Cette voie est impliquée dans la protection de l’organisme contre les troubles liés aux espèces radicalaires. En somme, ce travail met en avant les potentialités de la vectorisation d’antioxydants avec des nanoparticules à des fins thérapeutiques. / The purpose of this study is to explore the effects of nanoparticles (silver and silica) manufactured on oxidative and inflammatory metabolism. In the first part of this work, we explored the in vivo toxicity from ingestion of silver nanoparticles, for 11 weeks, in an animal model - Sprague Dawley rat. This enabled us to demonstrate the toxic properties of silver nanoparticles including superoxide anion production by hepatic and cardiac NADPH oxidases, dyslipidemia, hepatic cytolysis, an increase in proinflammatory cytokines and a downward trend the activity of antioxidant enzymes. This led us to address the in vitro study on intestinal cell models (Caco-2) and cutaneous (HaCaT). During this study, silica nanoparticles, functionalized or not with anti-oxidants, were incubated for 24 hours in the presence of the cells. We show that the modification of the surface of the nanoparticles significantly reduces their toxicity limiting the production of free radical species and cell death. Furthermore, the coupling with an anti-oxidant increases the stimulation of Nrf2 factor that involves the protection of the body against disorders associated with radical species. In summary, this work highlights the potential of vectorization of antioxidants with nanoparticles for therapeutic purposes.

En el dise��o de embutidos crudos curados enriquecidos en fibra alimentaria, es esencial la obtenci��n de ingredientes funcionales de elevada calidad, que puedan ser incorporados en la formulaci��n del embutido generando las menores modificaciones de las caracter��sticas f��sico-qu��micas y sensoriales del alimento. El principal objetivo de este trabajo consisti�� en optimizar la formulaci��n de un embutido crudo curado enriquecido en un concentrado de fibra alimentaria de zanahoria. La formulaci��n ��ptima debe proporcionar el contenido m��ximo de fibra alimentaria y producir los m��nimos cambios de calidad respecto al producto tradicional. Se ha propuesto una metodolog��a para optimizar ambos, la obtenci��n de un concentrado de fibra alimentaria de alta calidad y tambi��n la formulaci��n de un embutido crudo curado (sobrasada) enriquecido en fibra alimentaria. En primer lugar, se ha desarrollado un procedimiento que consiste en la modelizaci��n, simulaci��n y optimizaci��n del proceso de secado convectivo de zanahoria. El procedimiento de optimizaci��n no solo se refiere a la transferencia de materia, sino tambi��n se incluyen los criterios relacionados con los atributos de calidad del producto final. Una vez obtenido el ingrediente funcional de calidad, fue incorporado en la formulaci��n de la sobrasada. La cantidad ��ptima de concentrado de fibra alimentaria de zanahoria necesaria para obtener un embutido enriquecido de calidad se estim�� mediante el an��lisis de los efectos de la adici��n de fibra alimentaria de zanahoria en el proceso de maduraci��n-secado de sobrasada. / To design dry fermented sausages enriched in dietary fibre, it is essential to obtain high quality functional ingredients, which can be incorporated into sausage formulation with minor modifications of the physico-chemical and sensory properties of food. The main objective of this study was to optimize the formulation of a dry fermented sausage enriched with a dietary fibre concentrate from carrot. The optimal formulation should provide maximum dietary fibre content and produce minimal quality changes from the traditional product. A methodology has been proposed to optimize both the acquisition of a high quality fibre concentrate and also for the formulation of a dry fermented sausage (sobrassada) enriched in dietary fibre. First, a procedure comprised of mathematical modelling, simulation and optimization of the convective carrot drying process was developed. The optimization procedure was not only concerned with mass transfer but also included criteria related to quality attributes of the final product. Once the high quality functional ingredient was obtained, it was incorporated into the sobrassada formulation. The optimal amount of carrot dietary fibre concentrate necessary to obtain a high quality enriched sausage was estimated by analysing the effects of carrot dietary fibre addition to the ripening-drying process of sobrassada. / En el disseny d'embotits crus curats enriquits en fibra aliment��ria, ��s essencial l'obtenci�� d'ingredients funcionals d'elevada qualitat que puguin ser incorporats en la formulaci�� de l'embotit generant les menors modificacions de les caracter��stiques fisicoqu��miques i sensorials de l'aliment. El principal objectiu d'aquest treball va consistir a optimitzar la formulaci�� d'un embotit cru curat enriquit en un concentrat de fibra aliment��ria de pastanaga. La formulaci�� ��ptima ha de proporcionar el contingut m��xim de fibra aliment��ria i produir la menor quantitat possible de canvis qualitatius respecte al producte tradicional. S'ha proposat una metodologia per optimitzar ambd��s aspectes esmentats, l'obtenci�� d'un concentrat de fibra aliment��ria d'alta qualitat i tamb�� la formulaci�� d'un embotit cru curat (sobrassada) enriquit en fibra aliment��ria. En primer lloc, s'ha desenvolupat un procediment que consisteix en la modelitzaci��, simulaci�� i optimitzaci�� del proc��s d'assecatge convectiu de pastanaga. El procediment d'optimitzaci�� no nom��s fa refer��ncia a la transfer��ncia de mat��ria, sin�� que tamb�� inclou els criteris relacionats amb els atributs de qualitat del producte final. Una vegada obtingut l'ingredient funcional de qualitat, va ser incorporat en la formulaci�� de la sobrassada. La quantitat ��ptima de concentrat de fibra aliment��ria de pastanaga necess��ria per obtenir un embotit enriquit de qualitat es va estimar mitjan��ant l'an��lisi dels efectes de l'addici�� de fibra aliment��ria de pastanaga en el proc��s de maduraci��/assecat de sobrassada.