In order to establish a profile of detoxification via glutathione conjugation, the level of urinary mercapturic acid excreted by a free-living male population and the effect of external environmental and genetic factors, such as consumption of vegetables, fruits, and meat, charbroiled food intake, tobacco, alcohol, caffeinated coffee, and marijuana use, exposure to chemicals and familial cancer incidence, were investigated. A subgroup of 30 subjects was randomly selected from 117 subjects who complied with the collection protocol. Three consecutive 24 hr urine samples of this subgroup were analyzed. The modified method of Seutter-Berlage et al (Chemical Porphyria in Man. Elsevier/North-Holland Biomedical Press, N.Y. 1979:233-236) was used for the quantitation of urinary mercapturic acid. The mean excretion of mercapturic acid was 0.27 mmole mercapturate (-SH)/24 hr and 18.1 umole -SH/mmole creatinine. An analysis of variance showed a large degree of inter- and intraindividual variability. The interindividual coefficients of variation in mmole -SH/24 hr and umole -SH/mmole creatinine were 37.7% and 31.2%, respectively. The intraindividual coefficients of variation in mmole -SH/24 hr and umole - SH/mmole creatinine were 32.4% and 30.1%, respectively. A higher (p≤0.05) excretion of mercapturic acid was observed among subjects with a high frequency of exposure to chemicals. The lack of significance of the other dietary, non-dietary, and genetic factors on the observed mercapturic acid excretion may be due to the large inter- and intravariability, the use of food consumption frequency in food intake analysis, and unequal sample sizes of subgroups. / Master of Science

Les analyses physico-chimiques des arômes du vin prennent aujourd’hui un essor considérable pour faciliter la prise de décision des professionnels de la vigne et du vin. Des analyses performantes, pour un certain nombre de molécules parmi les plus pertinentes, ont été développées (GC-MS, LC-MS). Cependant les techniques utilisées ne sont pas facilement transposables au sein des exploitations. L’objectif de cette thèse est donc de proposer un nouveau type de dosage peu onéreux et simple à mettre en œuvre. La technique envisagée est le dosage immunologique (tests ELISA) qui permet, pour quelques Euros, de doser directement sur le terrain les molécules pertinentes sans préparation préalable des échantillons. Les molécules visées (alkylméthoxypyrazines et précurseurs cystéinylés de thiols volatiles) sont présentes dans les vins de Cabernet Sauvignon et de Sauvignon blanc. / Analytical methods for the detection and quantification of wines aroma typically utilise HPLC-MS or GC-MS. The methods require some isolation and concentration step preceding the analysis. Enzyme-linked immunosorbent assays (ELISAs) are becoming either alternative complementary analytical tools to conventional methods because of their rapidity, sensitivity, selectivity, and low cost. In this Thesis, the applicability of ELISAs for detection and quantification of precursors of volatile thiols and alkylmethoxypyrazines, which have been isolated from wines, made from Cabernet Sauvignon or Sauvignon Blanc, are described.

Les réactions d'oxydation impliquant les composés phénoliques semblent induire des modifications non négligeables du profil chimique et sensoriel des vins. Les travaux concernent l’étude des mécanismes réactionnels impliquant certains thiols volatils, contributeurs de l’arôme distinctif et de la complexité des vins des différents cépages avec les composés phénoliques oxydés des vins blancs, principalement les flavan-3-ols. En solution modèle de composition proche du vin, une réactivité différente des thiols volatils selon leur nature chimique vis à vis des formes oxydées des flavan-3-ols a été établie. La synthèse et la caractérisation des adduits par RMN entre les principaux composés phénoliques des moûts et des vins blancs et le 3-sulfanylhexanol, présentant des nuances d’agrumes, a ensuite été réalisée en conditions d’oxydation chimique et enzymatique. La suivi cinétique de la formation des adduits par CLHP-ESI-SM a permis de mettre en évidence une réactivité du thiol spécifique vis à vis d’un substrat polyphénolique, d’établir le rôle catalytique des métaux (Fe2+) et la capacité antioxydante du dioxyde de soufre vis à vis de ces mécanismes réactionnels. La compréhension de mécanismes fondamentaux de la réactivité de la (+)-catéchine et de la (-)-épicatéchine en conditions œnologiques avec les thiols volatils nous a permis de décliner les travaux à l’étude de l’influence de la présence des flavan-3-ols au cours de la vinification et de l’élevage des vins sur ces composants de l’arôme des vins blancs. / Oxidation reactions involving phenolics might change wines chemical and sensory profile. The present work concern the study of reactional mechanisms implying certain volatile thiols, responsible of distinctiveness and complexity of various wines, with white wines oxidized phenolic compounds, mainly flavan-3-ols. In a model wine solution, a different volatile thiol reactivity pattern according to their chemical nature with respect to oxidized flavan-3-ols forms was established. The adducts synthesis and characterization by NMR between the principal white musts and wines phenolic compounds and the 3-sulfanylhexanol, presenting citrus fruits nuances, were carried out under chemical and enzymatic oxidation conditions. Their formation monitoring by HPLC-ESI-MS highlighted a specific reactivity of thiol with polyphenolic substrate and established the catalytic role of metals (Fe2+) as well as, the antioxidant effect of sulphur dioxide into these mechanisms. The comprehension of fundamental mechanisms for the reactivity of (+)-catechin and of (-)-epicatechin with volatile thiols in oenological conditions enabled us to elucidate the influence of flavan-3-ols into white wines aroma compounds during wine making and ageing.

Afin de caractériser les moûts de Melon B. et de Sauvignon Blanc en composition et de modéliser leur profil d'oxydation, diverses méthodologies analytiques quantitatives ont été développées et validées. La quantification par dilution isotopique des précurseurs de thiols a nécessité la synthèse de molécules marquées qui ont également servies de traceurs lors d'études de filiation dans des milieux complexes. Ainsi, au cours de la fermentation alcoolique, nous avons pu démontrer que le S-3-(hexan-1-ol)-glutathion (G3MH) et la S-4-(4-méthylpentan-2-one)-glutathion (G4MMP) sont métabolisés par la levure et libèrent le 3-mercaptohexan-1-ol (3MH) et la 4-méthyl-4-mercaptopentan-2-one (4MMP) avec des rendements de conversion molaires proches de 4,4 % et 0,3 % respectivement. La modélisation des phénomènes d'oxydation à l'échelle laboratoire a permis par ailleurs de vérifier, comme le laissaient supposer leurs structures chimiques, que les précurseurs de thiols ne sont pas dégradés par les mécanismes oxydatifs affectant les moûts. Au contraire, une formation de G3MH concomitante avec le pic de production du Grape Reaction Product (GRP) est observée. La validation de ces observations à l'échelle industrielle a été conduite par comparaison des pressurages traditionnel et inerté. L' élaboration d'un moût de Melon B. sous gaz inerte n'est pas favorable à la production de G3MH d'origine pré-fermentaire, et a pour conséquence une diminution des teneurs en 3MH dans les vins correspondants, sans pour autant, déprécier les qualités organoleptiques des vins jeunes. Pour le Sauvignon Blanc, le potentiel aromatique de type thiol n'est pas affecté par le type de pressurage, mais une diminution très significative en 3MH dans les vins issus des cuvées obtenues sous gaz inerte est observée. La voie du (E)-2-hexènal qui est certainement impliquée, pourrait expliquer cette perte aromatique. Ainsi, de manière globale, dans nos conditions expérimentales, une oxydation ménagée et raisonnée des moûts de Melon B., et dans une moindre mesure de Sauvignon Blanc, est favorable à la qualité aromatique des vins du Val de Loire. / In order to characterize Melon B. and Sauvignon Blanc musts in composition and to study their oxidation profiles, several analytical methodologies have been developed and validated. The quantification of thiols precursors by Stable Isotope Dilution Assay required the synthesis of labeled molecules, which have been used either as analytical standards or as tracers for relationship studies in complex matrices. Thus, we established that, during the alcoholic fermentation, the S-3-(hexan-1-ol)-glutathione (G3MH) and the S-4-(4-méthylpentan-2-one)-glutathione (G4MMP) are metabolized by the yeast to release the 3-mercaptohexan-1-ol (3MH) and the 4-méthyl-4-mercaptopentan-2-one (4MMP) with molar conversion yields close to 4.4 % and 0.3 % respectively. Oxidation mechanisms study at laboratory scale demonstrated that aromatic potential was not affected by oxidative reactions, as expected in regard to their chemical structures. On the contrary, the G3M H was produced in the same time as the Grape Reaction Product peak (GRP). The validation of these observations at industrial scale was conducted by comparing traditional and inerted pressing systems. The elaboration of a Melon B. must under inert gas was not in favor of a G3MH pre-fermentary production, which induced a decrease of 3MH concentration in wine without affecting the organoleptic qualities of young wines. For Sauvignon Blanc must, the aromatic potential was not affected by the kind of pressing systems but a significant decrease in 3MH was observed in the wines obtained with juices from the beginning of pressing. The E-(2)-hexenal pathway could certainly explain such aromatic losses. Thus, under our experimental conditions, a mild and controlled oxidation of Melon B. must and, in a certain extend of Sauvignon Blanc must, is in favor of the aromatic quality of wines from Loire Valley.

Le vin est un milieu complexe qui évolue tout au long des étapes devinification. Pour mieux appréhender ses qualités et ses défauts, de nombreuses équipesde recherche s’intéressent à la compréhension de la chimie du vin. Dans ce contexte, lesujet de ce mémoire concerne l’étude de l’évolution chimique de certaines moléculespolyphénoliques du vin sous conditions oxydantes et/ou acides, afin d’isoler et decaractériser de nouveaux composés susceptibles de se former dans le vin. Deux aspectssont examinés. Le premier concerne l’oxydation de deux flavano‐ellagitannins, lesacutissimines A et B, formées à partir d’un monomère de tannins condensés, lacatéchine, et d’un ellagitannin C‐glucosidique, la vescalagine, extraite du bois de chênepar le vin lors de l’élevage en barrique. Cette étude a permis d’isoler les mongolicaïnes Aet B et deux analogues du camelliatannin G et de mettre en évidence leur formation parun mécanisme d’autoxydation. Le deuxième aspect concerne l’évaluation desconséquences de la présence de certains polyphénols dans le vin sur les composésthiolés odorants. Leur comportement et leur réactivité chimiques sont décrits dans desmilieux différents, avec l’hémisynthèse de thio‐ellagitannins sous conditions acides, et laformation d’adduits thio‐catéchols et thio‐pyrogallols sous conditions oxydantes,transformations chimiques pouvant occasionner la perte des odeurs et arômes du vindus aux composés thiolés odorants. / The wine is a complex medium that evolves throughout the different stages ofthe wine making process. To understand both the qualities and defects of wine,numerous research team worldwide investigate the chemistry of wine. In this context,the subject of this thesis concerns the study of the chemical evolution of some winepolyphenolic molecules under oxidizing and/or acidic conditions in the aim of isolatingand characterizing new compounds likely formed in wine. Two aspects are examined.The first one is the study of the oxidation of two flavano‐ellagitannins, acutissimins Aand B, formed from a monomer of condensed tannins, catechin, and a C‐glucosidicellagitannin, vescalagin, extracted from oak wood by the wine solution during its agingin barrels. This study led to the isolation of mongolicains A and B and two analogues ofcamelliatannin G, and revealed their formation according to an autoxydationmechanism. The second aspect of this work concerns the consequences of the presencein wine of some polyphenols on wine odorous thiols. Their chemical behavior andreactivity are described in different media, with the hemisynthesis of thio‐ellagitanninsunder acidic conditions, and the formation of thio‐catechol and thio‐pyrogallol adductsunder oxidizing conditions, chemical transformations that could explain the loss ofodors and aromas due to wine odorous thiols.

Cysteamine (CA), which is an aminothiol drug medically known as Cystagon® was studied in this thesis. Cysteamine was reacted with a binary toxin called peroxynitrite (PN) which is assembled spontaneously whenever nitric oxide and superoxide are produced together and the decomposition of peroxyinitrite was monitored. PN was able to nitrosate CA in highly acidic medium and excess CA to form S-nitrosocysteamine (CANO) in a 1:1 with the formation of one mole of CANO from one mole of ONOOH. In excess oxidant (PN) the following 1:2 stoichiometric ratio was obtained; ONOO- + 2CA → CA-CA + NO2- + H2O . In alkali medium the oxidation of CA went through a series of stages from sulfenic acid, sulfinic acid and then sulfonic acid which was followed by the cleavage of the C-S bond to form a reducing sulfur leaving group, which is easily oxidized to sulfate. The nitrosation reaction was first order in peroxynitrite, thus implicating it as a nitrosating agent in highly acidic pH conditions. Acid catalyzes nitrosation reaction, whitst nitrate catalyzed and increased the amount of CANO product, This means that the nitrosonium cation, NO+ which is produced from the protonation of nitrous acid(in situ) as also contributing to the nitrosation of CA species in highly acidic environments. The acid catalysis at constant peroxynitrite concentrations suggests that the protonated peroxynitrous acid nitrosates at a much higher rate than the peroxynitrite and peroxynitrous acid. Bimolecular rate constants for the nitrosation of CA, was deduced to be 10.23 M-1 s-1. A linear correlation was obtained between the initial rate constants and the pH. The oxidation of CA was modeled by a simple reaction scheme containing 12 reactions.

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

M.Sc. / [AuCl(PPh3)] was reacted with mixed thiols in the presence of silver(I) oxide, resulting in complexes of the type [Au(SC6H4X)(PPh3)] X= Cl, NH2,CH2, forming silver chloride as a by-product. In addition to the above series [Au(SCH2(C6H4)3(2-C6H5(C6H4N)] was prepared via a different route, where [AuCl3(2-C6H5(C6H4N)] was reacted with benzyl mercaptan under reflux in the presence of silver(I) oxide for 3 h, forming silver chloride as a by-product. Palladium complex [PdCl2(2-C6H5(C6H4N)] was prepared by reacting [PdCl2(MeCN)] with 2-phenylpyridine at room temperature for 2 h. All complexes were characterized by 1H, 13C, 31P{H} NMR, IR, mass spectrometry and elemental analysis. Characterization of the starting materials [AuCl3(2-C6H5(C6H4N)] and [PdCl2(2- C6H5(6H4N)] by single crystal X-ray diffraction confirmed their chemical formula. All complexes were reacted with sulfur dioxide (SO2) and the reactions were monitored by electrochemistry and UV-vis spectroscopy. The electrochemical study of the complexes, using cyclic voltammetry (CV) and Osteryoung square wave voltammetry (OSWV), showed one anodic peak, which is due to gold(I/III) and an unresolved peak due to thiolate ligand. Upon bubbling of SO2 to the complexes, there was an immediate change of colour from clear to yellow, the CV results showing an increase in current of the gold(I/III) peak. UV-vis spectroscopy studies showed a shift of peak form 250-286 nm, upon bubbling of SO2 to complexes.

Foram investigadas as propriedades, a reatividade e a estrutura eletrônica dos complexos trans-[RuII(NH3)4(L)(NO)](X)3 [(1) L = 4-pic, (2) L = P(OEt)3] e trans-[RuIII(NH3)4(4-pic)(L\')](CF3SO3)3 [(3) L\' = NH3, (4) L\' = H2O] através de técnicas espectroscópicas, eletroquímicas e cálculos teóricos. A reatividade dos complexos foi avaliada com glutationa (GSH) e L-cisteína (CisSH). Nitroxil (HNO) e óxido nítrico (NO•) são os produtos da reação entre os complexos 1 e 2 com GSH e CisSH em solução aquosa (pH 4,0 e 7,5). Óxido nítrico, livre (NO•) e coordenado (RuII-NO•), foi identificado através de quimiluminescência (NOA) e EPR, respectivamente. HNO foi sugerida indiretamente por RMN 15N após a identificação da formação de amônia (NH3), hidroxilamina (NH2OH) e sulfinamida (GS(O)NH2). Os complexos 3 e 4 foram isolados e estudados experimentalmente por EPR, UV-vis, Voltametria Cíclica, Cristalografia de Raios X e teoricamente por LFT e DFT. A acidez (pKa) e a constante de substituição do ligante H2O pelo íon Cl- no complexo 3 foram calculados como 3,65 ± 0.05 (25 °C) e 2,5×10-4 M-1s-1 (55 ºC), respectivamente. Os espectros de EPR do complexo 3 apresentaram uma simetria axial (g⊥ > g||) mas com um crescente componente rômbico que demonstrou ser função da basicidade do solvente e da sua interação com o ligante H2O. Não foi observado efeito similar para o complexo 4 ou mesmo para o complexo [RuIII(NH3)5(H2O)](CF3SO3)3. A partir de cálculos de DFT demonstrou-se que a capacidade doadora π do ligante H2O é intensificada quando a interação com moléculas do solvente promove sua rotação no eixo de ligação N(pic)-Ru-O(aq) contendo o ligante receptor π 4-picolina. Uma análise usando LFT demonstrou que de fato um componente rômbico pode ser evidenciado de uma simetria C2v por uma simples torção do ligante H2O no eixo C2. Os complexos 3 e 4 também foram investigados quanto a sua capacidade de oxidar glutationa em solução aquosa nos pH 4,0 e 7,5. A reação teve como produtos os íons trans-[RuII(NH3)4(4-pic)(H2O)]2+(λmax = 394 nm, ε = 5400 M-1cm-1) e [RuII(NH3)5(4-pic)]2+ (λmax = 399 nm, ε = 6400 M-1cm-1) identificados por UV-vis, além de GSSG, originado da reação do radical GSo, e identificado por RMN 1H. A velocidade da formação dos complexos de Ru(II) nestas reações apresentou-se mais lenta na presença de EDTA porém voltando a aumentar com a adição do captador de radical PBN. Respectivamente, essas variações foram atribuídas ao efeito catalítico promovido por íons de metais de transição em solução e à captação do radical GS•, potencialmente um agente oxidante dos complexos de Ru(II). / The proprieties, reactivity and electronic structure of trans-[RuII(NH3)4(L)(NO)](X)3 [(1) L = 4-pic, (2) L = P(OEt)3] e trans-[RuIII(NH3)4(4-pic)(L\')](CF3SO3)3 [(3) L\' = NH3, (4) L\' = H2O] were studied through spectroscopic and electrochemical techniques, and theoretical calculations. The reactivity study of these complexes was performed with the glutathione (GSH) and L-cysteine (CisSH). Nitroxil (HNO) and nitric oxide (NO •) are the products from the reaction of 1 and 2 with GSH and CisSH in aqueous solution (pH 4.0 and 7.5). Free nitric oxide (NO •) and coordinated nitric oxide (RuII-NO •) were identified by chemiluminescence (NOA) and EPR, respectively. HNO was indirectly suggested by 15N NMR data by identifying ammonia (NH3), hydroxylamine (NH2OH) and sulfinamide (RS(O)NH2). The complexes 3 and 4 were isolated and studied experimentally by EPR, UV-vis, cyclic voltammetry, X-Ray Crystallography and theoretically by DFT and LFT. The acidity (pKa), and the constant replacement of the H2O ligand in the complex 3 by the ion Cl- were calculated as 3,65 ± 0.05 (25 °C) and 2.5 × 10-4 M-1s-1 (55 °C), respectively. The EPR spectra of complex 3 showed an axial symmetry (g⊥ > g||) but with a growing rhombic component that proved to be due to the solvent basicity and its interaction with the H2O ligand. No similar effect was observed for the compound 4 or to the [RuIII(NH3)5(H2O)](CF3SO3)3 complex. According to DFT calculations the H2O π-donor ability increased when the interaction with solvent molecules promotes its rotation on the bonding axis N(pic)-Ru-O(aq) containing the pi;-acceptor ligand 4-picoline. A LFT analysis showed that a rhombic component can be evidenced in a C2v symmetry by a simple twist of the H2O ligand in the C2 axis. The complexes 3 and 4 were also investigated for their ability to oxidize glutathione in aqueous solution at pH 4.0 and 7.5. The reaction produced the trans-[RuII(NH3)4(4-pic)(H2O)]2+ (λ max = 394 nm, ε = 5400 M-1cm-1) and [RuII(NH3)5(4-pic)]2+ (λ ;max = 399 nm, ε = 6400 M-1cm-1), besides of GSSG, originated from GSo radical reaction, which was identified by 1H NMR. The rate for Ru(II) formation in these reactions were slower in the presence than in absence of EDTA. This late effect can be reduce by the addition of the radical scavenger PBN. These variations have been interpreted respectively on basis of the transition metal ions catalytic effect and to the scavenger of GS • radical, a potentially oxidizing agent of Ru(II) complexes.

Foram investigadas as propriedades, a reatividade e a estrutura eletrônica dos complexos trans-[RuII(NH3)4(L)(NO)](X)3 [(1) L = 4-pic, (2) L = P(OEt)3] e trans-[RuIII(NH3)4(4-pic)(L\')](CF3SO3)3 [(3) L\' = NH3, (4) L\' = H2O] através de técnicas espectroscópicas, eletroquímicas e cálculos teóricos. A reatividade dos complexos foi avaliada com glutationa (GSH) e L-cisteína (CisSH). Nitroxil (HNO) e óxido nítrico (NO•) são os produtos da reação entre os complexos 1 e 2 com GSH e CisSH em solução aquosa (pH 4,0 e 7,5). Óxido nítrico, livre (NO•) e coordenado (RuII-NO•), foi identificado através de quimiluminescência (NOA) e EPR, respectivamente. HNO foi sugerida indiretamente por RMN 15N após a identificação da formação de amônia (NH3), hidroxilamina (NH2OH) e sulfinamida (GS(O)NH2). Os complexos 3 e 4 foram isolados e estudados experimentalmente por EPR, UV-vis, Voltametria Cíclica, Cristalografia de Raios X e teoricamente por LFT e DFT. A acidez (pKa) e a constante de substituição do ligante H2O pelo íon Cl- no complexo 3 foram calculados como 3,65 ± 0.05 (25 °C) e 2,5×10-4 M-1s-1 (55 ºC), respectivamente. Os espectros de EPR do complexo 3 apresentaram uma simetria axial (g⊥ > g||) mas com um crescente componente rômbico que demonstrou ser função da basicidade do solvente e da sua interação com o ligante H2O. Não foi observado efeito similar para o complexo 4 ou mesmo para o complexo [RuIII(NH3)5(H2O)](CF3SO3)3. A partir de cálculos de DFT demonstrou-se que a capacidade doadora π do ligante H2O é intensificada quando a interação com moléculas do solvente promove sua rotação no eixo de ligação N(pic)-Ru-O(aq) contendo o ligante receptor π 4-picolina. Uma análise usando LFT demonstrou que de fato um componente rômbico pode ser evidenciado de uma simetria C2v por uma simples torção do ligante H2O no eixo C2. Os complexos 3 e 4 também foram investigados quanto a sua capacidade de oxidar glutationa em solução aquosa nos pH 4,0 e 7,5. A reação teve como produtos os íons trans-[RuII(NH3)4(4-pic)(H2O)]2+(λmax = 394 nm, ε = 5400 M-1cm-1) e [RuII(NH3)5(4-pic)]2+ (λmax = 399 nm, ε = 6400 M-1cm-1) identificados por UV-vis, além de GSSG, originado da reação do radical GSo, e identificado por RMN 1H. A velocidade da formação dos complexos de Ru(II) nestas reações apresentou-se mais lenta na presença de EDTA porém voltando a aumentar com a adição do captador de radical PBN. Respectivamente, essas variações foram atribuídas ao efeito catalítico promovido por íons de metais de transição em solução e à captação do radical GS•, potencialmente um agente oxidante dos complexos de Ru(II). / The proprieties, reactivity and electronic structure of trans-[RuII(NH3)4(L)(NO)](X)3 [(1) L = 4-pic, (2) L = P(OEt)3] e trans-[RuIII(NH3)4(4-pic)(L\')](CF3SO3)3 [(3) L\' = NH3, (4) L\' = H2O] were studied through spectroscopic and electrochemical techniques, and theoretical calculations. The reactivity study of these complexes was performed with the glutathione (GSH) and L-cysteine (CisSH). Nitroxil (HNO) and nitric oxide (NO •) are the products from the reaction of 1 and 2 with GSH and CisSH in aqueous solution (pH 4.0 and 7.5). Free nitric oxide (NO •) and coordinated nitric oxide (RuII-NO •) were identified by chemiluminescence (NOA) and EPR, respectively. HNO was indirectly suggested by 15N NMR data by identifying ammonia (NH3), hydroxylamine (NH2OH) and sulfinamide (RS(O)NH2). The complexes 3 and 4 were isolated and studied experimentally by EPR, UV-vis, cyclic voltammetry, X-Ray Crystallography and theoretically by DFT and LFT. The acidity (pKa), and the constant replacement of the H2O ligand in the complex 3 by the ion Cl- were calculated as 3,65 ± 0.05 (25 °C) and 2.5 × 10-4 M-1s-1 (55 °C), respectively. The EPR spectra of complex 3 showed an axial symmetry (g⊥ > g||) but with a growing rhombic component that proved to be due to the solvent basicity and its interaction with the H2O ligand. No similar effect was observed for the compound 4 or to the [RuIII(NH3)5(H2O)](CF3SO3)3 complex. According to DFT calculations the H2O π-donor ability increased when the interaction with solvent molecules promotes its rotation on the bonding axis N(pic)-Ru-O(aq) containing the pi;-acceptor ligand 4-picoline. A LFT analysis showed that a rhombic component can be evidenced in a C2v symmetry by a simple twist of the H2O ligand in the C2 axis. The complexes 3 and 4 were also investigated for their ability to oxidize glutathione in aqueous solution at pH 4.0 and 7.5. The reaction produced the trans-[RuII(NH3)4(4-pic)(H2O)]2+ (λ max = 394 nm, ε = 5400 M-1cm-1) and [RuII(NH3)5(4-pic)]2+ (λ ;max = 399 nm, ε = 6400 M-1cm-1), besides of GSSG, originated from GSo radical reaction, which was identified by 1H NMR. The rate for Ru(II) formation in these reactions were slower in the presence than in absence of EDTA. This late effect can be reduce by the addition of the radical scavenger PBN. These variations have been interpreted respectively on basis of the transition metal ions catalytic effect and to the scavenger of GS • radical, a potentially oxidizing agent of Ru(II) complexes.