Teses / dissertações sobre o tema "Polyphénols et flavonoids"
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Tran, Dong tien. "Conception et synthèse de sondes moléculaires pour l'étude d'interactions polyphénol-protéine". Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0443/document.
Texto completo da fontePolyphenols are plant secondary metabolites. These natural substances, known for their antioxidant and anti-free radical properties, generally contribute to the protection of human health not only against cardiovascular and neurodegenerative diseases, but also against certain cancers and diabetes. In some cases, these beneficial biological effects could also be related to specific polyphenol-protein interactions. However, studying this type of interactions has suffered from the lack of adequate molecular tools. The work carried out during this thesis has included designing, synthesizing and evaluating modulable polyfunctional molecular probes carrying polyphenols as affinity substrates to analyze polyphenol-protein interactions. In this context, various probes harboring different kinds of polyphenols were synthesized. These probes could be used in chemical proteomics following an “Affinity-Based Protein Profiling” approach (ABPP) to identify a protein within complex protein mixtures, which has a specific affinity with a given polyphenol. These probes will also allow studying the interactions of a polyphenol with a given protein in real time in a qualitative way by surface plasmon resonance (SPR)
Ghnimi, Wafa. "Étude phytochimique des extraits de deux Euphorbiaceae : Ricinus communis et Jatropha curcas. Évaluation de leur propriété anti-oxydante et de leur action inhibitrice sur l’activité de l'acétylcholinestérase". Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0006/document.
Texto completo da fonteThe aim of this study is to promote two Euphorbiaceae plants the Ricinus communis and the Jatropha curcas, the first one is known for its oil used in the cosmetic products, whereas the second one is known especially for its seeds used in the production of biodiesel. For the castor plant, eight Tunisian populations are studied: Riadh Andalous, Nefza, Beja, Nabeul, Hammamet, Bouficha, Khanguet Hajej and Aouled Amer. For the jatropha, recently introduced in Tunisia, the plant material is collected from the Nabeul station (Tunisia). Eight populations coming from Arusha in Tanzania, Mozambique, Suriname and Brazil from regions of Paraná, Minas Norte, Mato Grosso, Regiao sudeste and Vale do Jequitinhonha are studied. In first, a bibliographic study is made. In second, the used materials and methods are cited. Fanilly, all the results are mentioned. The study shows that the phenolic compounds are higher in the leaves extracts than in the roots extracts for both species. The phytochemical study shows that the gentisic acid is the major phenolic compound identified in the castor plant extracts. In contrast, the epicatechin and the naringin are the most important phenolic compounds identified in the jatropha extracts. The GC-MS analysis reveals that the castor oil contains mainly the ricinoleic acid. For the jatropha oil, two major fatty acids are identified: the oleic and the linoleic acids. Results of the antioxidant properties of leaves and roots of both species indicate a positive correlation between the leaves and the roots activities and their contents of phenolic compounds. Furthermore, the anti-acetylcholinesterase activity of the tested extracts shows for the first time that some tested extracts are more active than the galantamine used as a positive control. Our study confirmed that, in addition to their oils, different extracts of the castor plant and the jatropha can be used for biological activities such as the scavenging free radicals and the inhibitory action of AChE enzyme, which is a major target for treatments against the Alzheimer's disease due to their high levels of phenolic compounds. Owing to the activities of the leaves and the roots extracts confirmed by this study, the agricultural exploitation of the castor plant and the jatropha can be economically more profitable
Achaintre, David. "Développement d’une nouvelle méthode analytique pour le dosage des polyphénols dans les fluides biologiques et application à l’épidémiologie du cancer dans la cohorte EPIC". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1239/document.
Texto completo da fontePolyphenols are secondary plant metabolites found in diet and more than 500 different compounds are found in more than 450 foods. Along the last 30 years, many in vitro and animals studies have suggested a beneficial role of polyphenols in chronic diseases such as cancer. However, epidemiological studies based mainly on dietary questionnaires are inconsistent. New methodologies with broader polyphenol coverage are required to quantify a large diversity of compounds within large scale epidemiological studies.The goal of this thesis is to develop methods to quantify a large number of polyphenols representative of the main classes and sub-classes in blood and urine, evaluate urinary excretions of polyphenols and their association with food consumption in an European population, evaluate concentrations in blood in a nested case-control study on colorectal cancer within the European prospective investigation study on cancer and nutrition (EPIC).After a short presentation of polyphenols and colorectal cancer in chapter II, an original method based on differential isotopic dilution and analyse by tandem mass spectrometry is developed to quantify 38 polyphenols in urine and presented in chapter III. This method is based on differential 12C-/13C- isotope labelling of polyphenols through derivatisation with isotopic dansyl chloride reagents. Different conditions for enzymatic hydrolysis of conjugated polyphenols, extraction and dansylation of unconjugated aglycones have been tested, optimized and validated for the measure of 37 polyphenols.Urinary excretion levels of these 37 polyphenols in 475 subjects within EPIC cohort from 4 European countries are presented in chapter IV. Large urinary excretion variability in the 4 European countries has been shown and significant correlations with the consumption of specific food containing polyphenols have been observed suggesting the possible used of some polyphenols as biomarker for food consumption.A similar method on plasma for the 37 polyphenols, based on differential isotopic dilution, is developed, validated and applied to 1618 samples within the EPIC cohort (Chapter V). Main changes compared to the method developed on urine are essentially difficulties to hydrolyse conjugated polyphenols and huge matrix effects but reduced by the isotopic dilution method.Finally, the study on the association between polyphenols exposure measured owing to plasmatic marker with colorectal cancer risk has been driven in a nested case-control study within the EPIC cohort and is presented in chapter VI. An inverse association between plasmatic concentrations of equol, and a positive association between homovanillic acid and colon cancer risk have been found.Results obtained constitute a new approach for future applications in large scale epidemiology study on polyphenols
Ben, Nasr Rania. "Investigation phytochimique, évaluation des activités larvicide et anti-acétylcholinestérase de différents extraits de Mercurialis annua L". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0155.
Texto completo da fonteThis work reports the link between the larvicidal activity and the chemical composition of the different extracts of the male and female feet of Mercurialis annua L. a Euphorbiaceae often used in traditional medicine. The plant material used in our study is collected in four regions of Tunisia located in different bioclimatic stages: Bizerte, Jandouba, Nabeul and Beja. This study includes a first part devoted to a bibliographic synthesis. The second part is devoted to experiments and results. Indeed, we evaluated the antioxidant activity of the different extracts using DPPH tests. The phenolic compounds were identified and quantified by liquid chromatography coupled with a UV detector and mass spectrometry (LC-UV-ESI / MS). Our results showed that methanolic extracts from male plants have higher antioxidant activity (AOA) than that detected in extracts from female plants. On the other hand, male and female plant extracts from Bizerte showed the highest AOA level. For both sexes, Beja plant extracts have the lowest AOA. Certain phenolic compounds such as: narcissin, gallocatechin, rutin, epigallocatechin and epicatechin have been identified and quantified by LC-MS. On the other hand, the larvicidal activity of the various aqueous extracts of Mercurialis annua L. against the larvae of Tribolium confusum (Du Val) showed that the mortality could reach 100% after 48 hours of exposure for certain extracts, this is confirmed. by their low LC50. Furthermore, the study of the anti-acetylcholinesterase activity of the extracts tested shows that they are more potent AChE inhibitors than galantamine used as a positive control.Our study confirmed that extracts of the leaves and seeds of both sexes of Mercurialis annua L., coming from different regions of Tunisia, can therefore be exploited for other biological activities, among which the inhibitory action of AChE. Indeed, these extracts are rich in phenolic compounds, which gives them this therapeutic property against Alzheimer's disease and scavenging free radicals
Le, Nest Gwénaëlle. "Pouvoir antioxydant et piégeur de radicaux libres de polyphénols de vin". Aix-Marseille 1, 2001. http://www.theses.fr/2001AIX11054.
Texto completo da fonteNay, Bastien. "Intérêts, statégies et approches expérimentales en synthèse chimique totale de flavanoi͏̈des et tanins condensés". Bordeaux 2, 1998. http://www.theses.fr/1998BOR2P100.
Texto completo da fonteZupanc, Kauss Tina. "Intérêt thérapeutique et formulation galénique des polyphénols dans le traitement des infections et inflammations". Bordeaux 2, 2007. http://www.theses.fr/2007BOR21501.
Texto completo da fonteImmune response can become a pathological process, leading to a joint matrix destruction in rheumatoid arthritis or to a chronic cachexia in African trypanosomosis. In both pathologies, new therapeutics are needed for a better patients care. Flavonols, non toxic vegetal compounds, could bring a therapeutic alternative in these diseases, but their anti-inflammatory and anti-parasitic effects should be proved and/or characterized. We evaluated therefore the therapeutic potential of two flavonols, quercetin and rutin, in view of their use in human medicine. The effects of non toxic doses of flavonols on macrophage inflammatory mediators' gene transcription and protein expression were studied. In vitro inhibition of TNFα? il1β and NO was also confirmed on rat adjuvant-induced arthritis model, showing a correlation between clinical signs of inflammation (clinical scores and cachexia) and serum inflammatory mediators. In addition, quercetin and rutin trypanocidal effects were demonstrated and the kinetics and dose-response relationship studied. Furthermore, the in vitro trypanocydal effect of vitamin C was highlighted. In vivo studies should confirm the effectiveness of these molecules in African trupanosomosis. A first galenic approach was also conducted in order to improve the bioavailability and consequent therapeutic effects of flavonols
Meng, Linghua. "Caractérisation et extraction par techniques séparatives membranaires de polyphenols actifs et fonctionnels de Perilla frutescens". Aix-Marseille 3, 2007. http://www.theses.fr/2007AIX30045.
Texto completo da fonteThe extraction of polyphenols of Perilla frutescens is optimized at the laboratory scale to obtain a red extract, rich in antioxidant. The extracted polyphenolics are identified by NMR and LC-MS. Coutaric acid, luteolin O-glucuronide and vicenin-2 are for the first time identified in Perilla. The extraction, the purification and the concentration of Perilla extracts in large quantity are carried out at the pilot plant scale using coupled-membrane process: cross-flow microfiltration (CFM) and reverse osmosis (RO) equipped with industrial-type membranes. The microfiltrated extracts were concentrated by RO and/or by evaporation, up to a volume reduction factor of 117. Stabilization of anthocyanin extracts was carried out by spray-drying pilot unit to preserve their antioxidant activity (AOA), determined using DPPH method. AOA and polyphenol composition of 10 Perilla chemovars were compared. Malonylshisonin and rosmarinic acid are the most active compounds amongst all phenolics extracted from Perilla samples
Perruchon, Sophie. "Synthèse et étude des relations structure-fonction des flavonoi͏̈des". Rennes 1, 2004. http://www.theses.fr/2004REN10006.
Texto completo da fonteFargeix, Guillaume. "Étude des mécanismes d'oxydation de flavonoïdes en relation avec leur activité antioxydante : effets anti- et pro-oxydants dans l'inhibition de la peroxydation lipidique par les flavonoïdes". Lyon 1, 2000. http://www.theses.fr/2000LYO10281.
Texto completo da fontePlet, Benoit. "La spectrométrie de masse dans l'étude de l'interaction entre protéines de la salive humaine et polyphénols : vers une approche analytique de l'astringence du vin". Bordeaux 1, 2007. http://www.theses.fr/2007BOR13353.
Texto completo da fonteMissaoui, Rafik. "Extraction verte et caractérisation des molécules bioactives dans les coproduits de la production d'asperge (Asparagus officinalis L.)". Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/31327.
Texto completo da fontePlants belonging to the family of Asparagaceae, especially asparagus (Asparagus officinalis L.) contain a wide range of bioactive molecules such as polyphenols, flavonoids and saponins. These compounds have several health properties: antioxidant, anticancer and cardioprotective effects. In addition to that asparagus production generates a significant amounts of co-products, making it a good choice for the valorisation through the production of bioactive extracts for the functional food market. In this study, carried out with a green biorefinery view, we used only ethanol and water under optimum conditions rather than other solvents sometimes adopted in extraction of bioactive molecules and which may be harmful for human health. Total polyphenol and flavonoid were determined in different segments of the asparagus stem (upper and lower parts), differents varieties of asparagus and co-products of the Guelph Millenium variety. Identification of polyphenols was performed by UPLC-MS/MS and quantification of saponins was performed by a spectrophotometric method. The optimization of the extraction of polyphenols and flavonoids was accomplished by modulating the temperature, the ethanol concentration and the solute/solvent ratio. The polyphenols present in asparagus are especially flavonoids and phenolic acids with a dominance for rutin (92%) .The polyphenols have been found to be more concentrated in the upper part of the asparagus stem (1.15 %) and represent 0.6 % for the basal parts of the stem and 1.4 % for the lower grade asparagus based on dry matter. The optimized extraction parameters are 80 % ethanol at 70 °C for 3 hours with a solute/solvent ratio of 1:40. This study is not limited to protect the environment by removing asparagus co-products from landfills, but adds values to these co-products. Key words : Asparagus, co-products, optimization, polyphenols, flavonoids, saponins, UPLC-MS/MS.
Adje, Félix Anoh. "Production par procédés membranaires couplés d'extraits polyphénoliques de Carapa procera, Delonix regia et Hibiscus sabdariffa. Détermination des structures moléculaires et des activités antioxydantes". Aix-Marseille 3, 2009. http://www.theses.fr/2009AIX30054.
Texto completo da fonteThe extraction of the polyphenols of Carapa procera leaves, of Delonix regia flowers and of Hibiscus sabdariffa calyx was optimized at laboratory scale to obtain a red extracts rich in antioxidants. Anthocyanins, flavonols and phenolic acids of these 3 endemic plants from Ivory Coast were characterized by LC-MS and NMR for the first time in the 2 first plants and confirmed in the third. Water maceration, 12-16h time, of locally dried samples, 1hour time ultrasound-assisted maceration, microfiltration and concentration of the extracts at pilot plant scale allowed the production of 250L of microfiltrate/plant processed with average MFT flows of 100 to 200 L. H-1. M-2. B-1 at 0,6 bar, the volume concentration of the microfiltrates of 100 to 120 times with 16 and 20 L. H -1. M -2 fluxes at 40 bar and at 20°C and to produce powders by atomization, with a 5 to 10 % yield, of polyphenolic extracts (30 in 160 [micro]mol. L-1 AG eq), of which the antioxidant capacity was determined by DPPH and ABTS (from 8 to 30 mmol. L-1 AG eq for RO concentrates and from 220 to 500 mmol. G-1 TEAC for powders)
Chepkwony, Sarah Cherono. "Étude de la variabilité et modification chimique du Mesquitol, extractible polyphénolique de Prosopis juliflora : application à la préservation du bois". Electronic Thesis or Diss., Université de Lorraine, 2019. http://docnum.univ-lorraine.fr/ulprive/DDOC_T_2019_0258_CHEPKWONY.pdf.
Texto completo da fonteEarlier work from the laboratory (LERMaB, France) helped to highlight that the heartwood of Prosopis juliflora contains significant amounts of mesquitol, a relatively rare flavonoid with antioxidant properties, otherwise identified as 2-(3,4-dihydroxyphenyl)chromane-3,7,8-triol. P. juliflora has been rated among the worst world invasive species and therefore this study aimed at finding solutions to this menace that is fast spreading into areas that are otherwise intended for useful purposes like farming or grazing. With no data existing on the exact amounts of mesquitol present in P. juliflora or its variability depending on the geographic location of the tree or the tree’s age, the study commenced by first availing this data. This was done by a substantive study on P. juliflora stem samples that had been collected from three different geographic regions in Kenya (Baringo County, Garissa County and Turkana County). Compounds identification and quantification were done one using the GC-MS and the LC-ESI-MS/MS. A systematic study on the mass spectra and the observed fragmentations illustrated a rich array of phenolic compounds present in P. juliflora. Among these compounds is a mesquitol dimer, which has been identified for the very first time here. The results also showed that mesquitol compound is the most abundant compound in P. juliflora with high amounts of 11 % being found in the heartwood of the big trees from Baringo County. The second part of the study focused on the chemical modification of mesquitol targeting specific derivatives which could enhance the lipophilicity of mesquitol hence help in decreasing leachability. Various reactions of mesquitol with various carboxylic acids were performed allowing grafting of long fatty chains (lipophilic part) onto mesquitol through the aliphatic 3-OH position. Some of these derivatives were used to evaluate their ability to protect wood against fungal attack from both a white-rot and a brown-rot fungus. From the results of this study, it is evident that mesquitol derivatives obtained from reaction with carboxylic acids can be used as wood preservatives when used together with low amounts of tebuconazole
Chanet, Audrey. "Impact des flavanones des agrumes sur la prévention de l'athérosclérose et mécanismes d'action mis en jeu". Thesis, Clermont-Ferrand 1, 2011. http://www.theses.fr/2011CLF1MM02.
Texto completo da fonteCardiovascular disease is a major cause of mortality worldwide and its prevention is a major public health issue. Epidemiological studies have shown that fruit and vegetables consumption is associated with a lower cardiovascular risk. These effects could be explainedby their richness in micronutrients, especially polyphenols. Consumption of flavanones, a class of polyphenols present specifically and in large amounts in citrus fruits, was inversely associated with risk of coronary events and stroke. Experimental data obtained in vivo and invitro suggest that the flavanones (hesperidin or naringin) have lipid-lowering, hypotensive and anti-inflammatory properties. These effects could be mediated via modulation of gene expression by these bioactives. However, the anti-atherogenic effect of flavanones in vivo has been only explored at supra-nutritional doses and the mechanisms responsible for these effects are largely unknown. Furthermore, in vitro mechanistic data are questionable as they have been obtained using native forms of flavanones which are not present in the body.The objectives of this thesis were: (1) to assess the impact of consumption of flavanones (naringin and hesperidin) at nutritional doses on the development of atherosclerotic lesions indifferent mouse models of hypercholesterolemia and decipher molecular mechanisms brought into play, using a transcriptomic approach, (2) to determine the impact of physiological concentrations of plasma flavanone metabolites on endothelial cell function and theunderlying molecular mechanisms. In vivo, we showed that only naringin supplementation (0.02%), the major flavanonein grapefruit, reduced the progression of atherosclerotic lesions in a mouse model of dietinduced atherosclerosis (C57BL/6J mice fed an enriched diet in fat and cholesterol). Thiseffect was associated with a reduction in plasma non-HDL-Chol and biomarkers ofendothelial dysfunction, but appeared independent of a modulation of antioxidant status. Agenome-wide transcriptome analysis of the aorta of these animals showed that naringin supplementation modulated expression of genes involved in processes such as cell adhesion and cytoskeleton organization; these latter being involved in leukocytes trans-endothelialmigration. These results reveal new molecular targets of action of flavanones that have beenfurther studied in vitro.The in vitro data showed that exposure of endothelial cells (HUVEC) to physiological concentrations of circulating metabolites of naringenin (glucuronides) or hesperetin(glucuronides and sulfate) decreased the adhesion of monocytes (U937) to endothelial cells, a key step in the trans-endothelial migration. Consistent with these results, a TaqMan Low Density Array analysis showed that exposure of endothelial cells to these flavanone metabolites affected the expression of genes involved in inflammation, chemotaxis, adhesionas well as leukocytes trans-endothelial migration. Overall, the results of this work show that the anti-atherogenic effect of flavanones is not exclusively derived from lipid-lowering effect, but also due to a direct action on the endothelium by modulating key processes of atherosclerosis development, particularly adhesion and trans-endothelial migration
Dangleterre, Laëtitia. "Apport des spectroscopies moléculaires à l'étude des mécanismes de fixation des ions métalliques polluants par les substances humiques : complexation de Al(III), Pb(II) et Zn(II) par des systèmes modèles". Lille 1, 2007. http://www.theses.fr/2007LIL10068.
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