Dans le procédé de gazéification, la biomasse est transformée à haute température dans des conditions catalytiques, en produits gazeux qui peuvent avoir différentes utilisations : la production de gaz de synthèse (Syngas), la production de chaleur ou d'électricité, la synthèse de biocarburants, etc. Ce procédé est cependant générateur de goudrons et de particules, de part la matière première d'origine végétale. Il est donc nécessaire de connaître et d'optimiser les conditions de gazéification afin de minimiser la production de goudron. Les études ont porté sur l'optimisation des conditions opératoires dans un réacteur à lit fluidisé sur des coques d'amandes et des granules de miscanthus x giganteus. L'efficacité du lit a été évaluée en utilisant des systèmes catalytiques tels olivine, Ni olivine, Fe-olivine complétés par un système secondaire de bougies filtrantes à activité catalytiques. Au final, l'association d'un lit catalytique (Fe-olivine) et bougies catalytiques permet d'améliorer la conversion de la biomasse. Afin de suivre l'efficacité de la conversion des composés aromatiques, chaque composant des goudrons a été dosé par CLHP. En parallèle, d'autres approches ont été validées : elles permettent d'effectuer un suivi en ligne de la formation des goudrons lors de la gazéification. L'intérêt de la chromatographie sur couche mince a permis un dosage des composés aromatiques totaux par ajouts doses. Une analyse semi-quantitative est également possible après séparation par famille de composés aromatiques en fonction du nombre de noyaux et du degré de condensation, ces développements sont totalement originaux pour le suivi des goudrons issus de la biomasse / Gasification could be defined as a group of processes that converts solid or liquid fuels into a combustible gas. Therefore, biomass gasification can be employed to meet different market needs. Among the different gasification technologies available, fluidized bed gasifiers are very attractive because they take the advantage of the excellent mixing characteristics and high reaction rates of gas-solid mixtures. Miscanthus x giganteus (mxg) pellets and crushed and sieved almond shells have been used as biomass feedstock. Comparing the results obtained using the two biomasses at analogous operating conditions, no significant differences concerning the gas yield, gas composition and tar content could be observed. During the work, innovative catalytic hot gas filters for in-situ tar and particulate abatement, as well as two interesting Ni and Fe based catalyst have were tested in real gasification conditions. Further improvements have been obtained by combining the synergic catalytic effect of Fe-olivine and the catalytic filter candle, resulting in a efficient Tar abatement (-92% in the producer gas), and a consequently increase of gas yield by 72%. Also, the use of catalytic filter allows efficient particle separation so that the final result is a hot and clean fuel gas made available right at the exit of the gasifier reactor. The composition of tar was followed by HPLC as reference method. Other methods like HPTLC allow the separation of aromatic compounds according their number of aromatic rings. Quantification without separation was validated in order to control on line the production of tar during the gasification process

Fitoestrógenos são compostos naturais de origem vegetal com atividade estrogênica. Estão sendo amplamente investigados para a prevenção de doenças crônicas, coronarianas, câncer de próstata e mama, na redução de riscos de osteoporose e alívio nos sintomas da menopausa. Entre os fitoestrógenos já utilizados encontram-se a daidzeína, genisteína e gliciteína em matrizes complexas como drogas e extratos vegetais, cápsulas e comprimidos, requerendo desenvolvimento e validação de metodologias para a determinação das isoflavonas. As metodologias propostas foram a cromatografia em camada delgada de alta eficiência (CCDAE) e a cromatografia líquida de alta eficiência (CLAE). A fase móvel acetato de etila:hexano (8:2 v/v) foi utilizada para determinação do perfil cromatográfico das isoflavonas agliconas daidzeína, gliciteína e genisteína e a fase móvel acetato de etila:tolueno:ácido fórmico (8: 1: 1 v/v/v) para isoflavonas glicosiladas e não glicosiladas por CCDAE. Para a determinação quantitativa das isoflavonas glicosiladas por CLAE foi proposta uma hidrólise ácida com HCl 3M e aquecimento em banho-maria durante uma hora, como tratamento prévio. A determinação analítica das isoflavonas daidzeína, genisteína, formononetina e biochanina A por CLAE, em modo isocrático foi realizada utilizando coluna cromatográfica monolítica Chromolith® RP-18, 100-4,6mm, fase móvel constituída por água:acetonitrila (6:4 v/v), vazão 0,6mL/min e detecção a 260nm. Os resultados obtidos mostraram linearidade com coeficiente de correlação de 0,9995 para daidzeína, 0,9996 para genisteína, 0,9997 para formononetina e 0.9999 para biochanina A. A precisão e a exatidão apresentaram resultados satisfatórios. Boa resolução e rápida separação dos fármacos em formulações farmacêuticas também foram obtidas. Portanto, pode ser usado nas análises de rotina nos laboratórios de controle de qualidade de fitoterápicos. / Phytoestrogens are natural compounds of plants with estrogenic activity. They are being widely investigated in the prevention of chronic coronary diseases, in prostate and breast cancer, in the reduction of osteoporosis risk and relief of menopause symptoms. Among phytoestrogens already in use are daidzein, genistein and glycitein and they are present in complex matrix such as phytopharmaceuticals, plant extracts, capsules and tablets. These preparations require development and validation of methodologies for quantitative determination of isoflavones. The proposed methodologies include high performance thin layer chromatography (HPTLC) and high performance liquid chromatography (HPLC). The HPTLC coupled with densitometry can be used for quantitative analysis. The mobile phase constituted of ethyl acetate:hexane (8:2 v/v) was used to determine chromatographic profiles of isoflavone aglycones, daidzein, glycitein and genistein. The mobile phase constituted of ethyl acetate:toluene:formic acid (8:1:1 v/v/v) was used for determination of isoflavones glycosides and non-glycosides. For the quantitative determination of isoflavone glycosides with HPLC, an acid hydrolysis with 3M HCl and heating in water-bath for an hour was proposed as sample pretreatment step. The analytic determination of isoflavones daidzein, genistein, formononetin and biochanin A using HPLC was accomplished. The chromatography was carried out in isocratic mode with Chromolith®, a monolithic RP-18 column, (100x4.6mm) with mobile phase constituted of water:acetonitrile (6:4 v/v) operated at a flow rate of 0.6mL/min and detection was made at 260nm. The results showed method linearity with correlation coefficient of 0.9995 to daidzein, 0.9996 for genistein, 0.9997 for formononetin and 0.9999 for biochanin A. The precision and accuracy data presented satisfactory results. Good resolution and faster separation of compounds in pharmaceutical formulations were also obtained. The proposed method can be used in the routine analyses of phytopharmaceuticals in quality control laboratories.

Fitoestrógenos são compostos naturais de origem vegetal com atividade estrogênica. Estão sendo amplamente investigados para a prevenção de doenças crônicas, coronarianas, câncer de próstata e mama, na redução de riscos de osteoporose e alívio nos sintomas da menopausa. Entre os fitoestrógenos já utilizados encontram-se a daidzeína, genisteína e gliciteína em matrizes complexas como drogas e extratos vegetais, cápsulas e comprimidos, requerendo desenvolvimento e validação de metodologias para a determinação das isoflavonas. As metodologias propostas foram a cromatografia em camada delgada de alta eficiência (CCDAE) e a cromatografia líquida de alta eficiência (CLAE). A fase móvel acetato de etila:hexano (8:2 v/v) foi utilizada para determinação do perfil cromatográfico das isoflavonas agliconas daidzeína, gliciteína e genisteína e a fase móvel acetato de etila:tolueno:ácido fórmico (8: 1: 1 v/v/v) para isoflavonas glicosiladas e não glicosiladas por CCDAE. Para a determinação quantitativa das isoflavonas glicosiladas por CLAE foi proposta uma hidrólise ácida com HCl 3M e aquecimento em banho-maria durante uma hora, como tratamento prévio. A determinação analítica das isoflavonas daidzeína, genisteína, formononetina e biochanina A por CLAE, em modo isocrático foi realizada utilizando coluna cromatográfica monolítica Chromolith® RP-18, 100-4,6mm, fase móvel constituída por água:acetonitrila (6:4 v/v), vazão 0,6mL/min e detecção a 260nm. Os resultados obtidos mostraram linearidade com coeficiente de correlação de 0,9995 para daidzeína, 0,9996 para genisteína, 0,9997 para formononetina e 0.9999 para biochanina A. A precisão e a exatidão apresentaram resultados satisfatórios. Boa resolução e rápida separação dos fármacos em formulações farmacêuticas também foram obtidas. Portanto, pode ser usado nas análises de rotina nos laboratórios de controle de qualidade de fitoterápicos. / Phytoestrogens are natural compounds of plants with estrogenic activity. They are being widely investigated in the prevention of chronic coronary diseases, in prostate and breast cancer, in the reduction of osteoporosis risk and relief of menopause symptoms. Among phytoestrogens already in use are daidzein, genistein and glycitein and they are present in complex matrix such as phytopharmaceuticals, plant extracts, capsules and tablets. These preparations require development and validation of methodologies for quantitative determination of isoflavones. The proposed methodologies include high performance thin layer chromatography (HPTLC) and high performance liquid chromatography (HPLC). The HPTLC coupled with densitometry can be used for quantitative analysis. The mobile phase constituted of ethyl acetate:hexane (8:2 v/v) was used to determine chromatographic profiles of isoflavone aglycones, daidzein, glycitein and genistein. The mobile phase constituted of ethyl acetate:toluene:formic acid (8:1:1 v/v/v) was used for determination of isoflavones glycosides and non-glycosides. For the quantitative determination of isoflavone glycosides with HPLC, an acid hydrolysis with 3M HCl and heating in water-bath for an hour was proposed as sample pretreatment step. The analytic determination of isoflavones daidzein, genistein, formononetin and biochanin A using HPLC was accomplished. The chromatography was carried out in isocratic mode with Chromolith®, a monolithic RP-18 column, (100x4.6mm) with mobile phase constituted of water:acetonitrile (6:4 v/v) operated at a flow rate of 0.6mL/min and detection was made at 260nm. The results showed method linearity with correlation coefficient of 0.9995 to daidzein, 0.9996 for genistein, 0.9997 for formononetin and 0.9999 for biochanin A. The precision and accuracy data presented satisfactory results. Good resolution and faster separation of compounds in pharmaceutical formulations were also obtained. The proposed method can be used in the routine analyses of phytopharmaceuticals in quality control laboratories.

<p>IC2, a well known monoclonal autoantibody, derived from newly diabetic BB rat and seems to be an important biomarker for non-invasive functional imaging of beta cells in vivo. It specially and uniquely binds with pancreatic beta cells as confirmed in some previous studies. RIN-5AH is a pancreatic beta cell, which reacts with IC2 is used here to identify and characterize the molecular nature of the IC2 auto antigen by using TLC and HPTLC following by immuno-staining. An unpublished work already had done by Spitalnik et al, 1991 with another rat pancreatic beta cell (RINm5F) extracted glycolipids. In this study, the same work was done, not only with glycolipids from various cell lines but also lipids extracted from purified plasma membrane is made to confirm or refuge that IC2 was found to bind with only the glycolipids containing galactose-3-sulfate. This highly unique observation can however hardly explain the unique beta cell surface specificity without involvement of other more beta cell specific antigenic structures. We are therefore also searching the protein part involved in the auto antigenic determinant. Analyzing the molecular nature of IC2 binding auto-antigen, will help to understand both the role it might plays in the pathogenesis of insulin dependant diabetes. It could also help to elucidate the etiology of diabetes and finally to be a new serum autoantibody biomarker.</p>

IC2, a well known monoclonal autoantibody, derived from newly diabetic BB rat and seems to be an important biomarker for non-invasive functional imaging of beta cells in vivo. It specially and uniquely binds with pancreatic beta cells as confirmed in some previous studies. RIN-5AH is a pancreatic beta cell, which reacts with IC2 is used here to identify and characterize the molecular nature of the IC2 auto antigen by using TLC and HPTLC following by immuno-staining. An unpublished work already had done by Spitalnik et al, 1991 with another rat pancreatic beta cell (RINm5F) extracted glycolipids. In this study, the same work was done, not only with glycolipids from various cell lines but also lipids extracted from purified plasma membrane is made to confirm or refuge that IC2 was found to bind with only the glycolipids containing galactose-3-sulfate. This highly unique observation can however hardly explain the unique beta cell surface specificity without involvement of other more beta cell specific antigenic structures. We are therefore also searching the protein part involved in the auto antigenic determinant. Analyzing the molecular nature of IC2 binding auto-antigen, will help to understand both the role it might plays in the pathogenesis of insulin dependant diabetes. It could also help to elucidate the etiology of diabetes and finally to be a new serum autoantibody biomarker.

Techn. Universiẗat, Diss., 2004--Berlin.

Dans le but de valoriser la biodiversité végétale des Alpes-Maritimes, une plante commune dans cette région, Solidago virgaurea, a été sélectionnée pour son potentiel inhibiteur de la conversion levure-hyphe de Candida albicans, micro-organisme responsable d’infections bucco-dentaires de type candidose. Le fractionnement bioguidé de l’extrait aqueux a conduit à l’identification d’une famille de saponines particulièrement active. Parmi les onze saponines majoritaires caractérisées par RMN et HRMS, cinq se sont révélées être de nouvelles structures. Les tests biologiques ont néanmoins montré qu’elles n’étaient pas toutes actives contre la forme filamenteuse de C. albicans. Ces résultats ont conduit à une étude de la variabilité de la composition en saponines de plusieurs populations alpines de S. virgaurea. Trois méthodes de dosage des saponines ont été développées par HPLC et HPTLC. Les résultats ont démontré l'influence de différents facteurs sur la composition en saponines. Enfin, la composition globale de différents extraits de S. virgaurea a été étudiée dans le but d'identifier des activités biologiques complémentaires. Parmi les composés identifiés, trois nouveaux acides octulosoniques ont été caractérisés, aux côtés de trois composés phénoliques identifiés pour la première fois chez S. virgaurea. Les tests biologiques sur les extraits et fractions ont par ailleurs mis en évidence des activités antioxydante, anti-tyrosinase et inhibitrice de cellules cancéreuses in vitro. Ces tests devront être approfondis ultérieurement. / Toward the promotion of plant diversity of Maritime Alps, a common plant of the alpine area, Solidago virgaurea, was chosen to its inhibiting activity of Candida albicans yeast-hyphal conversion, a causal agent of opportunistic oral infections named candidiasis. In a first step, an aqueous extract of S. virgaurea was submitted to bioassay guided fractionation. This led to an active saponin-containing fraction from which eleven saponins were characterized by carrying out NMR experiments along with HRMS analyses. Five out of these were identified for the first time and bioassays showed that saponins activity varied according to the molecular structure of the compound. In a second step, the saponins composition of various S. virgaurea populations was studied qualitatively and quantitatively, using HPLC and HPTLC. Results demonstrated that saponins composition depends on various factors. Finally, the overall chemical composition of different S. virgaurea extracts was investigated searching for additional bioactivities. Among all the identified compounds, three new octulosonic acids were characterized and three phenolic compounds were found for the first time in S. virgaurea. Moreover, bioassays on extracts and fractions showed antioxidant, anti-tyrosinase activity and inhibition of cancer cell lines in vitro. Further bioassays have now to be completed. As a conclusion, this work was the starting point of an oral care product development and the setting-up of an innovative sector.

Ce projet vise à étudier, par une approche pluridisciplinaire, l’influence des la cristallisation des protéines membranaires (PM) en prenant pour protéine modèle le complexe photosynthétique RC-LH1-pufX de Rhodobacter blasticus. Des cristaux de ce complexe avaient été obtenus en présence de dodécyl-!-maltoside (DDM) et avaient diffractés à 8 Å de résolution. L’objectif final est de pouvoir améliorer, de façon rationnelle, la qualité des cristaux du complexe RC-LH1-pufX grâce à une meilleure compréhension des mécanismes mis en jeu. Dans un premier temps, trois tensioactifs dérivés du DDM ont été conçus et synthétisés. L’intérêt est d’augmenter la rigidité et le caractère lipophobe des parties hydrophobes des tensioactifs par rapport au DDM, pour les rendre moins déstabilisants envers la protéine: soit par l’incorporation d’un groupement bicyclohexyle (PCC-maltoside), soit par l’ajout d’un segment fluoré de longueur modulable (F4H5- et F2H9-maltoside). Nous avons inclus également le F8TAC, tensioactif fluoré utilisé depuis une vingtaine d’années pour le maintien en solution des PM, et les "tripodes", amphiphiles faciaux dont la géométrie particulière n’avaient jamais été testée. Nous avons ensuite réalisé la caractérisation physico-chimique, en solution, de ces tensioactifs et du DDM en terme de CMC (concentration micellaire critique), nombre d’agrégation, taille (par diffusion de la lumière dynamique, DLS), facteur de forme (par diffusion des rayons X aux petits angles, SAXS) et facteur de structure (par mesure du second coefficient du viriel, indicateur du potentiel des tensioactifs à initier la cristallisation)afin de déterminer les caractéristiques importantes au maintien en solution et à la cristallisation des PM. Le PCC-malt présentant le même comportement que le DDM,nous l’avons sélectionné pour réaliser une étude en présence de la protéine.Après avoir mis au point une méthode de dosage des tensioactifs par HPTLC (HighPerformance Thin Layer Chromatography) et identifier les lipides présents dans les de Rhodobacter blasticus, nous avons pu quantifier les quantités de lipides et de tensioactifs associés à la protéine en présence de DDM et de PCC-malt.Enfin, dans une dernière partie, nous avons réalisé des essais de cristallisation du complexe RC-LH1-pufX en présence des tensioactifs sélectionnés pour faire le lien entre les conditions de cristallisation et l’étude physico-chimique des micelles en solution. / Membrane proteins (MPs) are involved in the regulation of various fundamental cellular functions, such as cell recognition, receptor-mediated signal transduction and selective transportation of metabolites. However despite their huge importance, researches in MPs are relatively limited. For example MPs represent approximately 30% of the human proteome and less than 1% of current Protein Data Bank entries. Indeed, the presence of hydrophobic domains in MPs makes them not soluble in water. Therefore surfactants are used to extract MPs from their native environment and substitute for lipids around the transmembrane domain of the protein, forming water-soluble complexes. However MPs are often unstable in surfactant solution because of the intrusion of the alkyl chain of the surfactant into the transmembrane domain and/or the dissociation of stabilizing lipids, cofactors or subunits. Our project aims to study, through a multidisciplinary approach, the influence of surfactants for MP crystallization. Since dodecylmaltoside (DDM) is the most common gentle detergent used for MPs crystallization, we synthesized three new structurally DDM-derivative surfactants whose designs were expected to limit MPs inactivation. The objective was to increase the rigidity and the lipophobic behavior of the hydrophobic moiety by adding a bicyclohexyl group (PCC-maltoside) or using different lengths of fluorinated segments (F4H5- and F2H9-maltoside). Comparison of these surfactants with DDM occurs on:Physico-chemical properties: Surfactants are characterized by their CMC, molar mass (SEC-MALS, SAXS), hydrodynamic size (DLS), form factor (SAXS) and structure factor (A2, indicator of surfactant potential to lead to crystallization) in order to determine their best characteristics for MPs crystallization. Biochemical properties: We chose the RC-LH1-Puf X complex from Rhodobacter blasticus as model protein because of its biological interest. Besides this membrane protein has already been crystallized in DDM giving a low diffraction resolution (8Å). A better understanding of mechanisms involved in crystallization is a prerequisite for the development of rational approaches to increase crystals quality. Therefor protein complexes are characterized by quantifying lipids and surfactants bound to the transmembrane domain. Surfactant and lipid assays are performed by High Performance Thin Layer Chromatography (HPTLC). Crystallization trials: we show the link between crystallization and surfactants physico-chemical properties

Atualmente tem-se dado grande ênfase aos alimentos funcionais, pois atuam na prevenção e auxiliam na recuperação de várias doenças, como doenças inflamatórias crônicas, cardiovasculares e câncer, por apresentarem principalmente flavonoides, que previnem lesões oxidativas, propiciando benefícios à saúde. O Brasil é o maior produtor mundial do maracujá, e em vista disto é de suma importância o desenvolvimento de métodos analíticos e estudos de atividade antioxidante e anti-inflamatória do fruto de maracujá, visando sua possível utilização como alimento funcional e produção de possíveis fármacos. Passiflora edulis Sims. f. flavicarpa Degener, conhecida como maracujá azedo ou amarelo é a espécie mais cultivada e comercializada no Brasil. Desta forma, os objetivos deste trabalho foram: desenvolver e validar um método analítico por CLAE-UV/DAD (cromatografia líquida de alta eficiência acoplada detector de arranjo de fotodiodos) para quantificação da flavona isoorientina, presente na polpa de P. edulis; quantificação dos flavonoides totais desta espécie, usando um padrão de baixo custo (rutina); comparar as técnicas CLAE e CCDAE (cromatografia em camada delgada de alta eficiência) e analisar a isoorientina nas cascas dos frutos de P. edulis infectada com o vírus PWV e cascas sadias por CCDAE; quantificar as proteínas totais e avaliar as atividades antioxidantes e anti-inflamatória dos extratos de cascas de P. edulis e da polpa dos frutos de P. edulis e P. alata, empregando-se o método do DPPH&bull;, e os ensaios de QLluc (quimioluminescencia dependente de lucigenina), ELISA (Enzyme Linked Immunosorbent Assay), e SIEFED (Specific Immunologic Extraction Followed by Enzymatic Detection). Os resultados mostraram que o método desenvolvido por CLAE-UV/DAD foi adequado e eficiente para quantificação de isoorientina e de flavonoides totais na polpa de P. edulis, apresentando especificidade, linearidade, exatidão, precisão, dentro das faixas internacionalmente aceitas. Além disso, este método foi aplicado com sucesso nas análises de flavonoides em cascas de P. edulis e polpa de P. alata. O trabalho mostrou as vantagens da utilização da técnica CCDAE, como a realização de análises mais rápida e econômica, com baixo consumo de solvente e resíduos gerados frente à CLAE-UV/DAD. Por meio da técnica CL-EM/EM (cromatografia líquida acoplada à espectrometria de massas em tandem) foi possível identificar as flavonas isoorientina e isovitexina na polpa de P. edulis. Os extratos de cascas de P. edulis apresentaram maior capacidade redutora de radicais (método do DPPH&bull;), seguido das polpas de P. edulis e P. alata, respectivamente. Os extratos de cascas também mostraram maior inibição da produção de EROs (espécies reativas de oxigênio) pelos neutrófilos ativados e da atividade da MPO (mieloperoxidase) isolada, porém verificou-se que todos os extratos testados não modificaram a desgranulação dos neutrófilos, não influenciando a liberação de MPO no plasma. Assim, concluiu-se que a atividade antioxidante pode estar diretamente relacionada com a concentração de isoorientina presente nos extratos. A grande quantidade de proteínas e isoorientina encontrada nas cascas de P. edulis, se comparada à polpa de P. edulis, aliada à elevada atividade antioxidante e anti-inflamatória, sugere o potencial das cascas de P. edulis como um alimento funcional, ou como possível fonte de flavonoides naturais para a produção de fármacos, sugerindo assim o aproveitamento deste grande resíduo industrial. / Functional foods have been the focus of many studies nowadays, because they act preventing and assisting in the recovery of several diseases, such as chronic inflammatory, cardiovascular and cancer, due to they have mainly flavonoids, which prevent oxidative damage, providing health benefits. Brazil is the largest producer of passion fruit; therefore, it is very important to develop analytical methods and studies of antioxidant and anti-inflammatory activities of passion fruit, intending to its use as a functional food and in the development of drugs. Passiflora edulis Sims. f. flavicarpa Degener, known as yellow passion fruit, is the most cultivated and marketed species in Brazil. Therefore, the objectives were: to develop and validate an analytical method by HPLC-UV/DAD (high-performance liquid chromatography with photo-diode array detection) for quantification of isoorientin present in the pulp of P. edulis and quantification of total flavonoids of this specie, using a low-cost standard (rutin); to compare HPLC and HPTLC (high-performance thin layer chromatographic) techniques and to analyze isoorientin in the peels of P. edulis fruits infected by PWV virus and healthy peels by HPTLC; to quantify the proteins and to evaluate the antioxidant and anti-inflammatory activities of the extracts of P. edulis peels and P. edulis and P. alata pulp, using the method of DPPH&bull;, QLluc (chemiluminescence dependent of lucigenin), ELISA (enzyme linked immunosorbent assay), and SIEFED (specific immunologic extraction followed by enzymatic detection). The results showed that the HPLC-UV/DAD method was suitable and efficient for isoorientin quantification and total flavonoids in the P. edulis pulp, with specificity, linearity, accuracy, precision, within internationally acceptable limits. Moreover, this method was successfully applied to the analysis of flavonoids in the P. edulis peels and P. alata pulp. The study presented the advantages of using the HPTLC technique such as to perform faster and cheaper analysis, with low solvent consumption and waste generated compared to HPLC-UV/DAD. Using LC-MS/MS technique (liquid chromatography with tandem mass spectrometry detection) the flavones isoorientin and isovitexin were identified in the pulp of P. edulis. The extracts of peels of P. edulis showed the higher radical scavenging ability (DPPH&bull; method), followed by P. edulis and P. alata pulps, respectively. The peels extracts also showed greater inhibition of ROS (reactive oxygen species) production by neutrophils activated and isolated MPO activity, but it was found that the extracts did not alter the neutrophils degranulation and does not influence the MPO release in the plasma. Therefore, it was concluded that the antioxidant activity might be directly related to the concentration of isoorientin present in the extracts. The high amount of protein and isoorientin found in the P. edulis fruit peels, compared with P. edulis pulp, and the high antioxidant and anti-inflammatory activities, suggests the potential of the P. edulis fruit peels as functional food or a possible source of natural flavonoids for drugs production, suggesting the use of this substantial industrial waste.

Ce projet vise à étudier, par une approche pluridisciplinaire, l'influence des la cristallisation des protéines membranaires (PM) en prenant pour protéine modèle le complexe photosynthétique RC-LH1-pufX de Rhodobacter blasticus. Des cristaux de ce complexe avaient été obtenus en présence de dodécyl-!-maltoside (DDM) et avaient diffractés à 8 Å de résolution. L'objectif final est de pouvoir améliorer, de façon rationnelle, la qualité des cristaux du complexe RC-LH1-pufX grâce à une meilleure compréhension des mécanismes mis en jeu. Dans un premier temps, trois tensioactifs dérivés du DDM ont été conçus et synthétisés. L'intérêt est d'augmenter la rigidité et le caractère lipophobe des parties hydrophobes des tensioactifs par rapport au DDM, pour les rendre moins déstabilisants envers la protéine: soit par l'incorporation d'un groupement bicyclohexyle (PCC-maltoside), soit par l'ajout d'un segment fluoré de longueur modulable (F4H5- et F2H9-maltoside). Nous avons inclus également le F8TAC, tensioactif fluoré utilisé depuis une vingtaine d'années pour le maintien en solution des PM, et les "tripodes", amphiphiles faciaux dont la géométrie particulière n'avaient jamais été testée. Nous avons ensuite réalisé la caractérisation physico-chimique, en solution, de ces tensioactifs et du DDM en terme de CMC (concentration micellaire critique), nombre d'agrégation, taille (par diffusion de la lumière dynamique, DLS), facteur de forme (par diffusion des rayons X aux petits angles, SAXS) et facteur de structure (par mesure du second coefficient du viriel, indicateur du potentiel des tensioactifs à initier la cristallisation)afin de déterminer les caractéristiques importantes au maintien en solution et à la cristallisation des PM. Le PCC-malt présentant le même comportement que le DDM,nous l'avons sélectionné pour réaliser une étude en présence de la protéine.Après avoir mis au point une méthode de dosage des tensioactifs par HPTLC (HighPerformance Thin Layer Chromatography) et identifier les lipides présents dans les de Rhodobacter blasticus, nous avons pu quantifier les quantités de lipides et de tensioactifs associés à la protéine en présence de DDM et de PCC-malt.Enfin, dans une dernière partie, nous avons réalisé des essais de cristallisation du complexe RC-LH1-pufX en présence des tensioactifs sélectionnés pour faire le lien entre les conditions de cristallisation et l'étude physico-chimique des micelles en solution.