Dans ce travail, nous nous sommes intéressés au développement d’un nouveau biocapteur enzymatique ultrasensible pour la détection conductimétrique d’une mycotoxine, l’ochratoxine A (OTA). Une peptidase, la thermolysine (TLN), a été choisie comme élément de reconnaissance. Le biocapteur proposé est basé sur l’immobilisation de la TLN dans une matrice d’alcool polyvinylique (PVA)/polyéthylènimine (PEI) contenant des nanoparticules d’or et réticulée à la surface de microélectrodes interdigitées à l’aide de vapeurs de glutaraldéhyde. Dans les conditions optimales (35 min de réticulation, mesure à pH 7 et 25°C), la réponse du biocapteur est linéaire jusqu’à 60 nM et la limite de détection est de 1 nM. Cette valeur est 700 fois plus basse que celle obtenue en utilisant une méthode d’immobilisation basée sur la co-réticulation de la TLN en présence d’albumine de sérum bovin (BSA). La matrice PVA/PEI crée un environnement aqueux favorable à l’enzyme. Par ailleurs, les interactions entre les groupements amines protonés du PEI et les charges négatives des nanoparticules citratées et de la TLN améliore leur dispersion dans la matrice et favorise la stabilisation de l’enzyme et son accessibilité au substrat (OTA). Le biocapteur conductimétrique développé est très reproductible et stable pendant 30 jours lorsqu’il est stocké à 4°C dans du tampon phosphate 20 mM pH7 entre 2 mesures. Le biocapteur a ensuite été évalué sur des échantillons d’huile d’olive commerciale dopée. Aucun prétraitement de l’échantillon n’a été nécessaire et des taux de recouvrement proches de 100% ont été obtenus, démontrant l’absence d’effet de matrice / A new ultrasensitive enzymatic biosensor for the direct conductometric detection of ochratoxin A (OTA) has been developed in this work. Thermolysin (TLN), a peptidase, was chosen as recognition element. The proposed biosensor is based on TLN immobilization into a polyvinyl alcohol (PVA)/polyethylenimine (PEI) matrix containing gold nanoparticles (AuNPs) and cross-linked at the surface of gold interdigitated microelectrodes using glutaraldehyde vapor. Under optimal conditions (35 min cross-linking time, working pH of 7 and temperature of 25◦C), the biosensor response was linear up to 60 nM OTA and the limit of detection was 1 nM. This value was 700 times lower than the detection limit obtained using the more classical method based on enzyme cross-linking in the presence of bovine serum albumin (BSA). PVA/PEI hydrogel creates a very favorable aqueous environment for the enzyme. In addition, interactions between protonated amino groups of PEI and negative charges of both citrated AuNPs and thermolysin improve their dispersion in the polymer blend, favoring enzyme stabilization and accessibility to the substrate (OTA). The developed OTA biosensor was very reproducible and stable over a 30 days period when stored at 4◦C in 20 mM phosphate buffer between two measurements. The method was further evaluated using commercial doped olive oil samples. No pretreatment of the sample was needed for testing and no matrix effect was observed. Recovery values were close to 100%, demonstrating the suitability of the proposed method for OTA screening in olive oil

Dans un objectif de valorisation des huiles d’olive tunisiennes, les huiles de huit variétés autochtones : Chemchali, Chemlali Sfax, Chemlali Zarzis, Chétoui, Oueslati, Sayali, Zalmati et Zarrazi ont été étudiées et caractérisées par des techniques spectroscopique et chromatographique en tenant compte de leurs composés mineurs (acides gras mineurs, squalène, phénols totaux et α-, β- et γ-tocophérols). Une banque de données à été créé à partir des analyses de la composition en acides gras et des spectres proche infrarouge de 516 échantillons d’huiles d’olive vierges. Quatre outils d’authentification de l’origine variétale, basés sur l’utilisation des approches statistiques et chimiométriques associées aux données chromatographiques et spectrales, ont été élaborés. / In order to valorize the Tunisian olive oil production, eight autochthonous oil varieties (Chemchali, Chemlali Sfax, Chemlali Zarzis, Chétoui, Oueslati, Sayali, Zalmati and Zarrazi) were characterized by chromatographic and vibrational spectroscopy approaches. Fatty acid, squalene and near infrared spectra were analyzed in 516 samples which were used to create the data bank. Four origin varietal authentication tools were established using statistic and chemometric fatty acid treatment, NIR Spectra and olive oil minor fraction (minor fatty acids, squalene, totals phenols and α, β and γ-tocopherols).

Orientador: Helena Teixeira Godoy / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-24T06:47:07Z (GMT). No. of bitstreams: 1 Ballus_CristianoAugusto_D.pdf: 2840544 bytes, checksum: cd74911d057ffa04ee6e1e5b54ebc8e9 (MD5) Previous issue date: 2014 / Resumo: O consumo de azeite de oliva extravirgem (EVOO) é altamente recomendado por seus benefícios à saúde humana. No Brasil, a ingestão de EVOO, o qual é importado de outros países, vem aumentando anualmente. Nos últimos anos, o Brasil começou a produzir EVOO, porém de maneira experimental. No capítulo 1 foi apresentada uma revisão bibliográfica destacando os estudos mais relevantes acerca do composição química e dos benefícios à saúde do azeite de oliva extravirgem. No capítulo 2, o objetivo foi determinar o teor de fenólicos totais (TFT) e a capacidade antioxidante (CA), bem como a correlação entre o TFT e cada um dos quatro métodos de CA, de 15 marcas de EVOO, cada qual em três lotes, resultando em 45 amostras. O TFT foi avaliado pelo método do reagente de Folin-Ciocalteu, enquanto a CA foi determinada pelos ensaios de FRAP, ABTS, DPPH¿ e ORAC. O TFT variou de 70 a 297 mg EAG kg-1, FRAP de 114 a 1557 µmol ET kg-1, ABTS de 0,5 a 1,9 mmol ET kg-1, DPPH¿ de 72 a 1129 µmol ET kg-1, e ORAC de 1,1 a 12,9 µmol ET g-1. Houve elevada e significativa correlação entre o TFT e cada um dos métodos de CA (FRAP, r2 = 0,8904; p < 0,001; ABTS, r2 = 0,7837; p < 0,001; DPPH¿, r2 = 0,7908; p < 0,001; ORAC, r2 = 0,7431; p < 0,001). Portanto, a maioria das marcas de EVOO apresentaram considerável TFT e elevados valores de CA. No capítulo 3, o objetivo foi otimizar a separação de 17 compostos fenólicos previamente detectados em EVOO. Foi utilizado um planejamento experimental Doehlert, avaliando-se o pH e a concentração do eletrólito. Resolução, tempo de corrida e coeficientes de variação dos tempos de migração foram as respostas. A função de desejabilidade de Derringer foi utilizada para otimizar simultaneamente as 37 respostas. Os 17 picos dos compostos foram separados em 19 minutos em capilar de sílica fundida (50 µm diâmetro interno, 72 cm comprimento efetivo) com bulbo estendido e eletrólito ácido bórico 101,3 mmol L-1 (pH 9,15, 30 kV). O método foi validado e aplicado em 15 amostras comerciais de EVOO. No capítulo 4, o objetivo foi determinar o teor de compostos fenólicos, tocoferóis e ácidos graxos de 17 EVOO monovarietais produzidos em Minas Gerais, durante duas colheitas. Foram quantificados os ácidos palmítico (6-12,6%), palmitoleico (0,2-2,5%), esteárico (1,6-2,2%), oleico (70,8-84,3%), linoleico (3,2-11,7%), a-linolênico (0,6-1,4), araquídico (0,4-0,8%), 9-eicosenoico (0,4-0,9%) e os compostos tirosol (NQ-155,21 mg kg-1), (+)-pinoresinol (2,89-22,64 mg kg-1), hidroxitirosol (ND-37,74 mg kg-1), luteolina (ND-2,23 mg kg-1), a-tocoferol (28,92-232,93 mg kg-1), ß-tocoferol (ND-9,56 mg kg-1) e ?-tocoferol (ND-18,75 mg kg-1). Em geral, os resultados foram similares aos descritos na literatura. O objetivo do capítulo 5 foi determinar o teor de compostos fenólicos em EVOO brasileiros por cromatografia líquida de rápida resolução acoplada à espectrometria de massas por tempo de voo com ionização por electrospray (RRLC-ESI-TOF-MS). Foram analisadas 25 amostras de EVOO do Rio Grande do Sul, Santa Catarina e Minas Gerais e duas colheitas. Foram identificados e quantificados 20 compostos fenólicos das classes dos alcoóis fenólicos, secoiridoides, lignanas e flavonoides. Os teores de compostos fenólicos totais nos EVOOs destacaram-se nas variedades Coratina (364 mg kg-1), Arbosana (255 mg kg-1) e Grappolo (228 mg kg-1). Desta forma, os EVOOs brasileiros são promissores no que se refere ao teor de compostos fenólicos totais, visto que os valores são comparáveis àqueles dos EVOOs de elevada qualidade produzidos em outros países / Abstract: Consumption of extra-virgin olive oil (EVOO) is highly recommended for its benefits to human health. In Brazil, consumption of EVOO, which is imported from other countries, is increasing annually. In the last years, Brazil started to produce EVOO,although in an experimental way. In chapter 1, a literature review highlighting the most relevant studies on the chemical composition and the health benefits of the extra-virgin olive oil is presented. In chapter 2, the aim was to determine the total phenolic content (TPC) and the antioxidant capacity (AC), as well as the correlation between TPC and each one of the four AC methods, of 15 EVOO brands, each one in three batches, resulting in 45 samples. TPC was evaluated by Folin-Ciocalteu reagent method, while the AC was assessed using FRAP, ABTS, DPPH¿ and ORAC assays. The TPC varied from 70 to 297 mg GAE kg-1, FRAP from 114 to 1557 µmol TE kg-1, ABTS from 0.5 to 1.9 mmol TE kg-1, DPPH¿ from 72 to 1129 µmol TE kg-1, and ORAC from 1.1 to 12.9 µmol TE g-1. High and significant correlation was found between the TPC and each one of the AC methods evaluated in this study (FRAP, r2 = 0.8904; p < 0.001; ABTS, r2 = 0.7837; p < 0.001; DPPH¿, r2 = 0.7908; p < 0.001; ORAC, r2 = 0.7431; p < 0.001). Therefore, most of the EVOO brands presented a considerable TPC and high AC values. In chapter 3, the aim was to optimize the separation of 17 phenolic compounds already detected in EVOO. A Doehlert matrix experimental design was used, evaluating the effects of pH and electrolyte concentration. Resolution, runtime and migration time relative standard deviation values were used as responses. Derringer¿s desirability function was used to simultaneously optimize all 37 responses. The 17 peaks were separated in 19 minutes using a fused-silica capillary (50 mm internal diameter, 72 cm of effective length) with an extended light path and 101.3 mmol.L-1 of boric acid electrolyte (pH 9.15, 30 kV). The method was validated and applied to 15 EVOO samples found in Brazilian supermarkets. In chapter 4, the aim was to determine the phenolic compounds, tocopherols and fatty acids contents of 17 monovarietal EVOOs produced in Minas Gerais state, during two crop years. Compounds identified comprised palmitic acid (6-12.6%), palmitoleic acid (0.2-2.5%), stearic acid (1.6-2.2%), oleic acid (70.8-84.3%), linoleic acid (3.2-11.7%), a-linolenic acid (0.6-1.4), arachidic acid (0.4-0.8%), 9-eicosenoic acid (0.4-0.9%), tyrosol (NQ-155.21 mg kg-1), (+)-pinoresinol (2.89-22.64 mg kg-1), hydroxytyrosol (ND-37.74 mg kg-1), luteolin (ND-2.23 mg kg-1), a-tocopherol (28.92-232.93 mg kg-1), ß-tocopherol (ND-9.56 mg kg-1), ?-tocopherol (ND-18.75 mg kg-1). Some of these monovarietal EVOOs presented results similar to those described in the literature. The aim of chapter 5 was to determine the phenolic compound contents of Brazilian EVOO, using rapid-resolution liquid chromatography coupled to electrospray ionization time-of-flight mass spectrometry (RRLC-ESI-TOF-MS). A total of 25 EVOO samples from Rio Grande do Sul, Santa Catarina and Minas Gerais states and two crops, were analyzed. It was possible to identify and quantify 20 phenolic compounds, belonging to the phenolic alcohol, secoiridoid, lignan and flavonoid classes. EVOOs from Coratina (364 mg kg-1), Arbosana (255 mg kg-1) and Grappolo (228 mg kg-1) varieties presented the highest total phenolic contents. The results showed that Brazilian EVOOs are promising concerning the total phenolic contents, since the values were comparable to those from high-quality EVOOs produced in other countries / Doutorado / Ciência de Alimentos / Doutor em Ciência de Alimentos

Made available in DSpace on 2016-01-26T18:55:36Z (GMT). No. of bitstreams: 1 Leticia Parrilha.pdf: 1228823 bytes, checksum: 8118e9aa1d510f179a4087486f0ca68a (MD5) Previous issue date: 2013-03-28 / The objective of this study was to evaluate the effectiveness of topical 1% cyclosporine eye drops diluted in two vehicles, olive and the linseed seed oil and the oils separately in treating experimentally induced keratoconjunctivitis sicca (KCS) in rabbits. Twenty-five male New Zealand white rabbits were aleatory allocated in 3 groups: Group C (Control), Group CO (1% cyclosporine in olive oil), Group CL (1% cyclosporine in linseed oil), Group O (olive oil), Group L (linseed oil), being evaluated by Schirmer s Tear Test (STT), Fluorescein Test (FT), Tear Film Break-Up Time Test (TFBUT) and Rose Bengal Test (RBT), ocular cytology, and at the end of the experiment the rabbits were euthanized for histopathological analysis of cornea and conjunctive. The results demonstrated that there was significant increase in the values of STT in all the treated groups after the induction of KCS, presenting better acting the group CL. Regarding FT, there was a more rapid resolution of corneal ulcers in the groups O and L. For RBT, the group O was that it presented worse acting. The groups L and CL presented less edema and cornea congestion. There was significant increase in the number of caliciform cells in all of the treated groups, mainly in the group CL. The cyclosporine was efficient in the CCS treatment, diluted in linseed oil as in olive oil, however the linseed oil presented better effectiveness, associated or no, when compared to the oil olive. / O objetivo deste estudo foi avaliar a eficácia do uso tópico do colírio de ciclosporina 1% diluída em dois veículos, óleo de oliva e de semente de linhaça e dos óleos isoladamente, no tratamento de ceratoconjuntivite seca (CCS) induzida experimentalmente em coelhos. Foram utilizados vinte e cinco coelhos machos adultos brancos da raça Nova Zelândia alocados aleatoriamente em 5 grupos: Grupo C (controle), Grupo CO (ciclosporina 1% em óleo de oliva), Grupo CL (ciclosporina 1% em óleo de linhaça), Grupo O (óleo de oliva), Grupo L (óleo de linhaça), sendo avaliados pelo Teste Lacrimal de Schirmer (TLS), Teste de Fluoresceína (TF), Teste de Tempo de Ruptura do Filme Lacrimal (TRFL), Teste de Rosa Bengala (TRB), citologia ocular e ao final do experimento foram eutanasiados para análise histopatológica da córnea e conjuntiva. Os resultados demonstraram que houve aumento significativo nos valores de TLS em todos os grupos de tratamento após a indução da CCS, apresentando melhor desempenho o grupo CL. Com relação ao TF, houve resolução mais precoce das úlceras de córnea nos grupos O e L. Para o TRB, o grupo O foi que apresentou pior desempenho. Os grupos L e CL apresentaram menos edema e congestão de córnea. Houve aumento significativo no numero de células caliciformes em todos os grupos de tratamento, principalmente no grupo CL. A ciclosporina foi eficiente no tratamento da CCS tanto diluída em óleo de linhaça quanto em óleo de oliva, porém com o óleo de linhaça mostrou melhor eficácia, associada ou não, quando comparada ao óleo oliva.

Made available in DSpace on 2016-07-18T17:53:11Z (GMT). No. of bitstreams: 1 Leticia Parrilha.pdf: 1228823 bytes, checksum: 8118e9aa1d510f179a4087486f0ca68a (MD5) Previous issue date: 2013-03-28 / The objective of this study was to evaluate the effectiveness of topical 1% cyclosporine eye drops diluted in two vehicles, olive and the linseed seed oil and the oils separately in treating experimentally induced keratoconjunctivitis sicca (KCS) in rabbits. Twenty-five male New Zealand white rabbits were aleatory allocated in 3 groups: Group C (Control), Group CO (1% cyclosporine in olive oil), Group CL (1% cyclosporine in linseed oil), Group O (olive oil), Group L (linseed oil), being evaluated by Schirmer s Tear Test (STT), Fluorescein Test (FT), Tear Film Break-Up Time Test (TFBUT) and Rose Bengal Test (RBT), ocular cytology, and at the end of the experiment the rabbits were euthanized for histopathological analysis of cornea and conjunctive. The results demonstrated that there was significant increase in the values of STT in all the treated groups after the induction of KCS, presenting better acting the group CL. Regarding FT, there was a more rapid resolution of corneal ulcers in the groups O and L. For RBT, the group O was that it presented worse acting. The groups L and CL presented less edema and cornea congestion. There was significant increase in the number of caliciform cells in all of the treated groups, mainly in the group CL. The cyclosporine was efficient in the CCS treatment, diluted in linseed oil as in olive oil, however the linseed oil presented better effectiveness, associated or no, when compared to the oil olive. / O objetivo deste estudo foi avaliar a eficácia do uso tópico do colírio de ciclosporina 1% diluída em dois veículos, óleo de oliva e de semente de linhaça e dos óleos isoladamente, no tratamento de ceratoconjuntivite seca (CCS) induzida experimentalmente em coelhos. Foram utilizados vinte e cinco coelhos machos adultos brancos da raça Nova Zelândia alocados aleatoriamente em 5 grupos: Grupo C (controle), Grupo CO (ciclosporina 1% em óleo de oliva), Grupo CL (ciclosporina 1% em óleo de linhaça), Grupo O (óleo de oliva), Grupo L (óleo de linhaça), sendo avaliados pelo Teste Lacrimal de Schirmer (TLS), Teste de Fluoresceína (TF), Teste de Tempo de Ruptura do Filme Lacrimal (TRFL), Teste de Rosa Bengala (TRB), citologia ocular e ao final do experimento foram eutanasiados para análise histopatológica da córnea e conjuntiva. Os resultados demonstraram que houve aumento significativo nos valores de TLS em todos os grupos de tratamento após a indução da CCS, apresentando melhor desempenho o grupo CL. Com relação ao TF, houve resolução mais precoce das úlceras de córnea nos grupos O e L. Para o TRB, o grupo O foi que apresentou pior desempenho. Os grupos L e CL apresentaram menos edema e congestão de córnea. Houve aumento significativo no numero de células caliciformes em todos os grupos de tratamento, principalmente no grupo CL. A ciclosporina foi eficiente no tratamento da CCS tanto diluída em óleo de linhaça quanto em óleo de oliva, porém com o óleo de linhaça mostrou melhor eficácia, associada ou não, quando comparada ao óleo oliva.

Made available in DSpace on 2016-07-18T17:53:17Z (GMT). No. of bitstreams: 1 luis felipe zulim.pdf: 1410755 bytes, checksum: 10cd9caab094cc2991e4233b68367a1f (MD5) Previous issue date: 2016-05-05 / This study aimed to compare the efficacy of tacrolimus 0.03% eye drops diluted in two types of vehicle, flaxseed oil and olive oil in the treatment of keratoconjunctivitis sicca (CCS) in dogs. 60 dogs were used, twenty healthy dogs as a negative control group and 40 dogs diagnosed with bilateral CCS that were randomly divided into two groups, tacrolimus in olive oil (TO) and tacrolimus in flaxseed oil (TL). The dogs were evaluated monthly with ophthalmologic exams, Tear Test Schirmer (TLS), Break Test Tear Film (TRFL), Fluorescein test (TF), Test of Rose Bengal (TRB) and conjunctival cytology and at the beginning and end of the study with histopathological examination of the conjunctiva .In both groups, clinical signs, TLS, TRFL, TF and TRB showed significant improvement with one month of treatment. At study end in cytological and histopathologic evaluation, both groups showed a decrease of neutrophils, it is more significant in the TL group, and both groups showed an increase of goblet cells. Thus we can conclude that the drops of tacrolimus 0.03% diluted in olive oil and flaxseed oil was effective in the treatment of CCS and the TL group performed better as the decrease in neutrophils. Thus, the linseed oil may be a new alternative as the tacrolimus diluent. / O presente estudo teve como objetivo comparar a eficácia do colírio de tacrolimus 0,03% diluído em dois tipos de veículo, óleo de semente de linhaça e óleo de oliva, no tratamento de ceratoconjuntivite seca (CCS) em cães. Foram utilizados 60 cães, sendo vinte cães saudáveis como grupo controle negativo e 40 cães diagnosticados com CCS bilateral que foram alocados aleatoriamente em dois grupos, tacrolimus em óleo de oliva (TO) e tacrolimus em óleo de semente de linhaça (TL). Os cães foram avaliados mensalmente com exames oftálmicos, Teste Lacrimal de Schirmer (TLS), Teste de Ruptura do Filme Lacrimal (TRFL), Teste de Fluoresceína (TF), Teste de Rosa Bengala (TRB) e citologia conjuntival e no início e final do estudo com exame histopatológico de conjuntiva .Em ambos os grupos, os sinais clínicos, o TLS, TRFL, TF e TRB apresentaram melhora significativa com um mês de tratamento. Ao término do estudo na avaliação citológica e histopatológica, ambos os grupos apresentaram diminuição de neutrófilos, sendo ela mais significativa no grupo TL, e ambos grupos apresentaram aumento de células caliciformes. Desta forma podemos concluir que o colírio de tacrolimus 0,03% diluído em óleo de oliva e em óleo de semente de linhaça foi eficiente no tratamento de CCS e o grupo TL apresentou melhor desempenho quanto a diminuição de neutrófilos. Assim, o óleo de semente de linhaça pode ser uma nova alternativa como diluente do tacrolimus.

Les maladies d’Alzheimer et de Parkinson (MA et MP) sont des maladies neurodégénératives entrainant une diminution des fonctions cognitives et locomotrices et toujours dépourvues de traitements curatifs. La consommation d’huile d’olive et des polyphénols qu’elle contient atténuerait la survenue des démences telles qu’observées dans la MA ou la MP. À ce jour, ces composés phénoliques ont été étudiés de manière isolée afin de caractériser leur réactivité vis à vis des radicaux et leurs effets biologiques, mais les concentrations utilisées (5–100 µM) sont supérieures aux concentrations retrouvées dans le plasma (0.5-2,8 ng/ml). Jusqu’à présent, aucune étude n’a observé les effets de ces composés combinés, alors que l’oleuropéine et le tyrosol, des composés phénoliques parmi les plus abondants dans l’huile d’olive et que l’acide p-coumarique, un dérivé d’acide hydroxycinnamique, sont connus pour leurs activités antioxydantes et leur biodisponibilité. Dans un contexte cellulaire, les composés phénoliques agissent à travers leurs capacités de donneurs d’atomes d’hydrogène et/ou d’électrons, et impactent la régulation des défenses antioxydante. En conditions oxydatives, ils peuvent subir des modifications structurelles et mener à de nouveaux composés. L’impact cellulaire de ces derniers est encore peu étudié, car leur devenir dans le contexte d’un métabolisme oxydatif reste obscur. L’étude des métabolites issus de l’oxydation des composés phénoliques est donc d’une réelle importance afin d’approfondir les connaissances sur leurs mécanismes d’actions au niveau biologique. Nous avons émis l’hypothèse que la combinaison de l’oleuropéine, du tyrosol et de l’acide p-coumarique potentialise leurs effets neuroprotecteurs à travers leurs capacités de donneurs d’électrons et en lien avec la production des métabolites associés. Ce propose une approche pluridisciplinaire intégrant des composantes biologiques et des questions relevant de la physico-chimie, en s’appuyant sur des outils électrochimiques. En premier lieu, nous avons démontré que l’association de ces trois composés (Mix 1) permettait de potentialiser leurs effets neuroprotecteurs avec concentrations efficaces à 0.1 et 1µM, contrairement aux concentrations neuroprotectrices lorsque ces composés sont utilisés individuellement (5 à 10 fois plus élevées). Le Mix1 augmente la réactivité des composés phénoliques vis-à-vis d’espèces réactives de l’oxygène et permet une diminution de leur génération intracellulaire. Cette neuroprotection semble en partie médiée par une régulation des facteurs de régulation rédox endogènes. Dans un second temps, nous avons comparé le comportement en conditions oxydatives acellulaires de l’oleuropéine, du tyrosol et de l’acide p-coumarique individuellement et dans le Mix1. L’analyse en LC-MS2 des composés stables issus de l’oxydation du Mix 1 a montré une diminution des taux d’oxydation relatifs de chacun des composés, ainsi que la détection de trois néocomposés spécifiques de l’oxydation du Mix1. De plus, un effet neuroprotecteur significatif du Mix1 oxydé a été observé dès 1 et 5 nM, ce qui soutient l’hypothèse que les produits issus de l’oxydation des composés phénoliques peuvent participer aux effets biologiques des composés natifs. Notre troisième objectif était d’évaluer si les composés issus de l’oxydation des composés phénoliques pouvaient être générés dans un système biologique. L’analyse en LC-HRMS des extraits de cellules neuronales traitées avec le Mix1 en conditions oxydatives a révélé que ces composés étaient toujours présents sous leurs formes natives dans les cellules après plusieurs heures de traitement. Ce projet multidisciplinaire a permis d’observer les effets des composés phénoliques sous plusieurs angles. Il confirme qu’un effet neuroprotecteur de composés issus de l’oxydation est possible et ouvre la voie à de nouvelles approches pour le développement de formulations efficaces pour limiter le stress oxydatif au niveau cérébral. / Alzheimer and Parkinson diseases (AD and PD) are neurodegenerative disorders leading to cognitive function decline and curative treatments are still missing. Olive oil and related phenolic compounds consumption could prevent or slow down cognitive decline through neuronal preservation. Indeed, they have direct antioxidant properties as electrons or H-atom donors, which are largely suspected of being responsible for their biological effects, but also of some indirect properties as modulators of endogenous antioxidant defenses. The secoiridoid oleuropein and the monophenols tyrosol and p-coumaric acid have shown abilities to counteract oxidative injuries and associated neuronal death in several cellular and in vivo models. However, the basic mechanisms of action of phenolic compounds remain to be elucidated. In fact, phenolic compounds are highly sensitive to oxidative modifications and could be transformed into new compounds in an oxidative context. Cellular impacts of these products are rarely considered, probably because their intracellular detection is a great challenge and remain an important field to explore. Moreover, oleuropein, tyrosol and p-coumaric were individually evaluated in order to characterize their own reactivity towards ROS and their biological properties. However, the concentration ranges used to observe neuroprotection in cellular models (5 – 100 µM) were far from the possibly recovered phenolic concentration in plasma (0.5 - 2,8 ng /ml of plasma). To observe an effect with concentration range closer to the physiological ones, several antioxidant combinations could be proposed. Nevertheless, despite the biological promises of phenolic compounds from olive oil, studies which combined some of the most abundant phenolic compounds in the neuroprotection field is still missing. We thus hypothesized that the combination of oleuropein, tyrosol and p-coumaric acid in equimolar proportion (Mix 1) could potentiated their ROS scavenging and neuroprotective properties to counteract oxidative stress-induced neuronal death. These effects could be in part due to their oxidized metabolites. First, we demonstrated that the association of these three phenolic compounds potentiated their neuroprotective effects with efficient concentrations at 0.1 and 1µM, contrary to concentration ranges when there are used individually (5 to 10 higher). The Mix1 increase the reactivity of phenolic compounds towards ROS and decreases their intracellular production. These neuroprotective properties seems, at least in part, lead by a regulation of the endogenous redox factors. Then, we compared the behavior of Oleuropein, tyrosol and p-coumaric acid individually and in the Mix1 under acellular oxidative conditions. The oxidized Mix1 LC-ESI-MS2 profiles showed a regeneration of oleuropein through a decrease of the phenolic compounds oxidation rate and highlight the presence of specific oxidized products in Mix 1. This study also showed a significant neuroprotection of oxidized Ole and oxidized Mix1 with very low concentrations (1 and 5 nM), suggesting the putative relevant role of oxidized Ole products to protect or delay neuronal death. Our third objective was to evaluate if these oxidized metabolites could be produced in a biological system. Even under oxidative conditions, we recovered these compounds in cellular extracts under their native forms after few hours of treatments, attesting their accumulation in neuronal cells. Taking together, our results pointed out the relevance to study the phenolic compounds from a chemical and a biological point of view, which should always be as cellular redox reactions are between biological and chemical fields. Lastly, we confirmed the significance to take into account the oxidized metabolites from phenolic compounds to deeper understand their biological properties.

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A debate over environmental policies and trade competitiveness, “Do environmental policies really matter to impact trade competitiveness?” still exists during the past decade. The thesis aims at investigating the impact of WTO-EU environmental policies for the international olive oil market on production and export competitiveness of developing countries. In particular, we focus our analysis on the agro-industrial sector in the Arab countries, and we take specific reference to the case of the olive oil agro-industrial sector in Syria. In the frame of a partial equilibrium trade model, we incorporate the “end-of-the-pipe” environmental policies which in turn enhance the productivity of the polluting input. Moreover, a part of the burden of environmental compliance may be shifted onto foreign consumers. The most novel part of our model consists of the augmented effect of compliance with environmental policies, which includes not only the standard impact on the effective product price, but also on the input shadow price. The empirical findings, based on Syrian data, provide strong support to the Porter Hypothesis and its application to international markets for agro-industrial products. Accordingly, the study disproves the legitimacy of concerns that stricter environmental policies in developing economies may have negative impacts on their production and export competitiveness. In contrast, our results show that compliance with environmental policies under the large country assumption has positive effects on their international competitiveness of environmentally sensitive sectors, in particular. Therefore, the policy implications suggest the implementation of strict environmental regulatory policies supporting environmentally sound technologies.

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