As hortaliças são alimentos amplamente consumidos na dieta dos brasileiros. Há alguns anos, estudos sobre compostos presentes em vegetais, como os carotenóides, vitaminas, fibras e compostos fenólicos vem sendo bastante explorados devido aos seus possíveis efeitos biológicos e benefícios à saúde humana. Os compostos fenólicos são produtos do metabolismo secundário das plantas e se destacam principalmente por seu poder antioxidante. O objetivo deste trabalho foi avaliar os compostos fenólicos e a atividade antioxidante em algumas hortaliças consumidas no Brasil. Os métodos utilizados foram o do radical livre DPPH e ABTS, auto-oxidação do sistema -caroteno/ácido linoléico, redução do ferro, estabilidade oxidativa em Rancimat e identificação química por meio da técnica de cromatografia gasosa acoplada a espectrômetro de massas. Extratos etanólicos foram utilizados em todas as análises. O teor de compostos fenólicos variou entre 1,2 a 16,9 mg/g, sendo que a cenoura apresentou a menor quantidade e a alface a maior. As hortaliças que apresentaram a maior atividade antioxidante foram a alface (54,9% e 0,45 µmol Fe2+/mg), nos métodos do DPPH e FRAP , respectivamente, o açafrão (111,8µM trolox/g e 92,8%), nos métodos ABTS+ e -caroteno, o agrião e o brócolis no método do Rancimat (fator de proteção 1,29). Além dessas, a alcachofra, espinafre, e aspargo também apresentaram atividade antioxidante considerável. Os compostos fenólicos mais frequentemente encontrados nas amostras pela técnica de CG-EM foram os ácidos ferúlico, caféico e p-cumárico. O ácido ascórbico presente também contribuiu para a atividade antioxidante de alguns vegetais. Desta forma, pode-se verificar boa atividade antioxidante de várias hortaliças, ressaltando assim a importância em uma dieta equilibrada destes vegetais. / Vegetables are widely consumed foods in the diet of Brazilians. A few years ago, studies on compounds present in vegetables such as carotenoids, vitamins, fibers and phenolic compounds have been conducted due to their biological effects and benefits to human health. Phenolic compounds are distinguished mainly by their antioxidant power. The aim of this study was to evaluate the phenolic compounds and antioxidant activity in some vegetables consumed in Brazil. The methods for evaluating the antioxidant activity used were the DPPH free radical and ABTS, -carotene bleaching, reduction of Fe3+, oxidative stability in Rancimat, while the chemical composition used the gas chromatography - mass spectrometry technique (GC-MS). Ethanol extracts were used in all analysis. The content of phenolic compounds ranged from 1.2 to 16.9 mg / g, with carrots presenting the lowest amount and lettuce the highest. The vegetables with the highest antioxidant activity were lettuce (54.9% and 0.45 mmol Fe2+/ mg), through DPPH and FRAP methods, respectively, saffron (111.8 mM trolox / g and 92.8%) through the ABTS+ and -carotene methods, watercress and broccoli through the Rancimat method (protective factor 1.29). Besides these, the artichoke, spinach, and asparagus also showed considerable antioxidant activity. Phenolic compounds most frequently found through the GCMS technique were ferulic acid, caffeic acid and p-coumaric acid. Ascorbic acid also contributed to the antioxidant activity of some vegetables. Generally, it is confirmed the good antioxidant activity of some vegetables, emphasizing its importance in a balanced diet.

As hortaliças são alimentos amplamente consumidos na dieta dos brasileiros. Há alguns anos, estudos sobre compostos presentes em vegetais, como os carotenóides, vitaminas, fibras e compostos fenólicos vem sendo bastante explorados devido aos seus possíveis efeitos biológicos e benefícios à saúde humana. Os compostos fenólicos são produtos do metabolismo secundário das plantas e se destacam principalmente por seu poder antioxidante. O objetivo deste trabalho foi avaliar os compostos fenólicos e a atividade antioxidante em algumas hortaliças consumidas no Brasil. Os métodos utilizados foram o do radical livre DPPH e ABTS, auto-oxidação do sistema -caroteno/ácido linoléico, redução do ferro, estabilidade oxidativa em Rancimat e identificação química por meio da técnica de cromatografia gasosa acoplada a espectrômetro de massas. Extratos etanólicos foram utilizados em todas as análises. O teor de compostos fenólicos variou entre 1,2 a 16,9 mg/g, sendo que a cenoura apresentou a menor quantidade e a alface a maior. As hortaliças que apresentaram a maior atividade antioxidante foram a alface (54,9% e 0,45 µmol Fe2+/mg), nos métodos do DPPH e FRAP , respectivamente, o açafrão (111,8µM trolox/g e 92,8%), nos métodos ABTS+ e -caroteno, o agrião e o brócolis no método do Rancimat (fator de proteção 1,29). Além dessas, a alcachofra, espinafre, e aspargo também apresentaram atividade antioxidante considerável. Os compostos fenólicos mais frequentemente encontrados nas amostras pela técnica de CG-EM foram os ácidos ferúlico, caféico e p-cumárico. O ácido ascórbico presente também contribuiu para a atividade antioxidante de alguns vegetais. Desta forma, pode-se verificar boa atividade antioxidante de várias hortaliças, ressaltando assim a importância em uma dieta equilibrada destes vegetais. / Vegetables are widely consumed foods in the diet of Brazilians. A few years ago, studies on compounds present in vegetables such as carotenoids, vitamins, fibers and phenolic compounds have been conducted due to their biological effects and benefits to human health. Phenolic compounds are distinguished mainly by their antioxidant power. The aim of this study was to evaluate the phenolic compounds and antioxidant activity in some vegetables consumed in Brazil. The methods for evaluating the antioxidant activity used were the DPPH free radical and ABTS, -carotene bleaching, reduction of Fe3+, oxidative stability in Rancimat, while the chemical composition used the gas chromatography - mass spectrometry technique (GC-MS). Ethanol extracts were used in all analysis. The content of phenolic compounds ranged from 1.2 to 16.9 mg / g, with carrots presenting the lowest amount and lettuce the highest. The vegetables with the highest antioxidant activity were lettuce (54.9% and 0.45 mmol Fe2+/ mg), through DPPH and FRAP methods, respectively, saffron (111.8 mM trolox / g and 92.8%) through the ABTS+ and -carotene methods, watercress and broccoli through the Rancimat method (protective factor 1.29). Besides these, the artichoke, spinach, and asparagus also showed considerable antioxidant activity. Phenolic compounds most frequently found through the GCMS technique were ferulic acid, caffeic acid and p-coumaric acid. Ascorbic acid also contributed to the antioxidant activity of some vegetables. Generally, it is confirmed the good antioxidant activity of some vegetables, emphasizing its importance in a balanced diet.

De nouveaux composés anabolisants sont devenus accessibles via Internet : les modulateurs spécifiques des récepteurs androgènes (SARMs) actuellement développés pour le traitement des pertes musculaires. L’Ostarine® (MK-2866, GTX-024, enobosarm) en particulier, exerce ses effets sur les muscles squelettiques et ne présente pas d'activité androgénique. Sur la base de son mécanisme d’action et des résultats cliniques préliminaires, ce produit pourrait être utilisé comme promoteur de croissance en élevage bovin. Dans ce contexte, les objectifs de la thèse sont de valider des outils permettant de décrire les effets zootechniques pouvant être induits par l’administration orale d'enobosarm à des bovins et de développer des stratégies analytiques dédiées à la mise en évidence de son utilisation frauduleuse. En comparant animaux contrôles et animaux traités avec l'enobosarm, aucun effet morphologique n'a été mis en évidence en termes de croissance ou de conformation. Il a été ensuite démontré que l'enobosarm et ses principaux métabolites de phase II sont éliminés dans les urines et les fèces à des concentrations permettant leur détection par des techniques analytiques impliquant le couplage chromatographie en phase liquide et spectrométrie de masse. Enfin, une stratégie de type métabolomique conduite sur matrices urinaire et fécale a conduit à la description d’empreintes spécifiques et discriminantes pouvant signer l’administration d'enobosarm. Ce travail de recherche pluridisciplinaire contribue à générer des connaissances sur une nouvelle classe d'anabolisants, permettant par extension de contribuer à garantir au consommateur une sécurité chimique accrue des denrées d’origine animale. / New compounds with anabolic properties have recently become accessible via Internet-based suppliers: selective androgens receptor modulators (SARMs) currently developed for the treatment of chronic diseases with wasting muscle. Ostarine® (MK-2866, GTX-024, enobosarm), in particular, exerts its anabolic effects exclusively on the skeletal muscles and has no androgenic activity. Based on its mechanism of action and clinical preliminary results, this product could potentially be used as a growth promoter in cattle. In this context, the aims of this thesis are to validate tools allowing to describe the zootechnical effects that may be induced by an oral administration of enobosarm in calves and to develop analytical strategies dedicated to highlight its fraudulent use. Following a comparison between control animals and enobosarm treated animals, no morphological effect was visible and measurable in terms of growth and conformation. It was then demonstrated that enobosarm and its main phase II metabolites are eliminated in urine and feces at concentrations allowing their detection with analytical techniques using a liquid chromatography-mass spectrometry coupling. Finally, a metabolomics approach on urine and fecal matrices led to the description of specific and discriminant fingerprints signaling the administration of enobosarm. This multidisciplinary research work helps to generate knowledge on a new class of anabolic substance and therefore contributes to guarantee a more chemically-safe food of animal origin to the consumer.

Les retardateurs de flamme (RF) sont des substances utilisées dans de nombreux produits synthétiques pour limiter la propagation du feu et ainsi améliorer la sécurité des habitations et des lieux publics. En raison de leur stabilité, de leur bioaccumulation et de leur toxicité, l’utilisation massive de certains RF, en particulier halogénés parmi lesquels la famille de Dechloranes, génère cependant un problème de contamination de l’environnement qui pose aujourd’hui la question d’éventuelles répercussions sur la santé humaine. Les Dechloranes ont été détectés pour la première fois dans l’environnement en 2006 et préoccupent, depuis, la communauté scientifique et les autorités sanitaires. Le présent travail avait pour objectif de contribuer à combler le manque manifeste de données sur les niveaux de prévalence en Dechloranes.Pour ce faire, une stratégie analytique ciblée, dédiée à l’identification et à la quantification des Dechloranes à l’état de traces (pg/g) dans des denrées alimentaires d’origine animale (DAOA) et des huiles végétales et basée sur un couplage GC-HRMS a été développé. Une attention particulière a été portée à la maîtrise des contaminations procédurales, eu égard au caractère ubiquitaire de certains composés. L’application de la méthode développée à 378 échantillons de poissons d’eaux douces de surface en France et de DAOA et huiles végétale collectées en France, au Liban et dans quatre pays d’Afrique subsaharienne a permis de brosser le premier état des lieux des niveaux de contamination environnementale et alimentaire dans ces pays, jusqu’à estimer l'exposition alimentaire de leurs populations à ces composés persistants et émergents. / Flame retardants (FR) are substances used in many synthetic products to limit the spread of fire and thus improve the safety of homes and public places. Due to their stability, bioaccumulation and toxicity, certain FRs, in particular halogenated ones among which the family of Dechloranes, are widely used, generating an issue of environmental contamination with potential repercussions on human health. Dechloranes were detected for the first time in the environment in 2006 and have since raised concerns to the scientific community and health authorities. The purpose of this paper is to help fill the obvious gap in data on prevalence levels of Dechloranes. To this end, a targeted analytical strategy dedicated to the identification and quantification of trace amounts of Dechloranes (pg/g) in animal foods (DAOA)and vegetable oils based on a GC-HRMS method has been developed. Particular attention has been paid to the control of procedural contaminations, given the ubiquitous nature of certain compounds. This method was applied to 378 samples of surface freshwater fish in France and DAOA and vegetable oils collected in France, Lebanon and four sub-Saharan African countries, and draw for the first time an inventory of levels of environmental and food contamination in these countries to estimate the dietary exposure of their populations to these persistent and emerging compounds