La levure de riz rouge dans le traitement de l'hypercholestérolémie

L'hypercholestérolémie est un facteur de risque dans la survenue de maladies cardiovasculaires, seconde cause de mortalité en France. Ce facteur de risque modifiable peut être traité par des règles hygiéno-diététiques qui, si elles échouent sont relayées par des thérapeutiques chimiques. L'Afssaps recommande en premier lieu l'utilisation de statines. La levure de riz rouge est un produit de fermentation issu de la culture de Monascus Purpureus sur le riz. Elle est connue depuis des siècles en Asie, son continent d'origine, où elle est utilisée à des fins alimentaires. En Europe ou aux Etats-Unis, elle est plutôt considérée comme un complément alimentaire intéressant par la présence de monacoline k ou lovastatine, faisant d'elle une statine naturelle. Cette thèse a repris les études faites sur la levure de riz rouge. Elles ont confirmé son action bénéfique, mais ont aussi montré ses limites comme les effets indésirables qui peuvent survenir ainsi que les interactions médicamenteusesHypercholesterolemia is a risk factor of cardiovascular disease, second cause of mortality in France. This risk factor is modifiable and can be treated with therapeutics lifestyle changes. If unsuccessful, chemicals drugs are proposed. Afssaps recommended the use of statines as first-line. The red yeast rice is a fermentation product derived from the culture of Monascus Purpureus on rice. It has been known for centuries in Asia, the continent of origin, where it is used for food. In Europe or the United-states, it is rather cosidered a dietary supplement interesting by the presence of lovastatin or monacolin k, making it a natural statin. This thesis sets out the differents studies on red yeast rice. Some confirm its efficacy, others describe rather limits such as side effects or drugs interactions.LYON1-BU Santé (693882101) / SudocRENNES1-BU Santé (352382103) / SudocSudocFranceF

Implication de deux composés naturels dans la maladie d'alzheimer (le resvératrol et la caféine)

Avec l'allongement de la durée de vie, l'incidence de la maladie d'Alzheimer augmente de façon très importante dans les pays développés. Il s'agit d'un enjeu médical, scientifique, social et économique majeur. C'est dans ce contexte que la nutrition a toute sa place car elle peut influencer le processus de vieillissement cérébral. Plusieurs rapports épidémiologiques ont établi le lien entre une consommation modérée de vin rouge et de café et une plus faible incidence de la maladie. Les bienfaits sont respectivement attribués au resvératrol et à la caféine. Les études en laboratoire montrent que les actions anti-oxydante, anti-inflammatoire, neuroprotectrice et anti-amyloïdogène du resvératrol en font un candidat thérapeutique prometteur pour la maladie d'Alzheimer. Des études plaident en faveur d'un effet protecteur de la caféine contre la maladie grâce à une action anti-inflammatoire, anti-oxydante et protectrice vis-à-vis de la barrière hémato-encéphalique. La caféine restaurerait les fonctions cognitives chez des souris et réduirait les dépôts amyloïdes caractéristiques de la maladie d'Alzheimer.With the lengthening of life, the incidence of Alzheimer's disease increases dramatically in developed countries. It is a medical, social and economic challenge. It is in this context that nutrition has its place because it can influence the process of brain aging. Several epidemiological reports have established the link between a moderate consumption of red wine and coffee and a lower incidence of the disease. The benefits are respectively attributed to resveratrol and caffeine. Laboratory studies show that the antioxidant action, anti-inflammatory activity, neuroprotective and anti-amyloidogenic effects of resveratrol make it a promising therapeutic candidate for Alzheimer's disease. Studies suggest a protective effect of caffeine through an anti-inflammatory and antioxidant potential and the protective action of the blood-brain barrier. Caffeine restore cognitive function in mice and reduce amyloid deposits characteristic of Alzheimer's disease.LYON1-BU Santé (693882101) / SudocRENNES1-BU Santé (352382103) / SudocSudocFranceF

Detection and chemical reactivity of lichen secondary metabolites using in situ DART-MS

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Study of the self-association of molecular tweezers bearing two different arms: influence of the stereoelectronic effects of the arm substituents

International audienceIn the general field of molecular recognition, the self-assembly of a tweezer bearing a R(+) usnic acid arm and a substituted 1,8-naphthalimide moiety as a second arm was investigated through a H-1 NMR study. Two self-association modes were evidenced either the usnic acid arms (mode A) or the naphthalimide ones (mode B) were face to face in the center of the dimer. The existence of a third non-symmetrical mode (mode C) has not been evidenced experimentally. The behavior of these tweezers was discussed taking into account the electronic density of the naphtalimide arms and the slow mode A/mode B exchange rate (EXSY experiments). Only the mode A was observed when naphthalimide was either non-substituted (1) or substituted by Br (2). With one or two electrodonating substituents (OCH3 (3) or (OCH3)(2) (4) or N(CH3)(2) (5)) both modes A and B occured in a 50/50 ratio. This ratio depended on temperature for tweezer 3

1H NMR and computational study of the conformations in solution of one host/guest complex formed with an usnic acid tweezer and 2,4,7-trinitro-9-fluorenone (TNF)

International audienceIn a host-guest model formed by a molecular tweezer 4, bearing two usnic acid units, and TNF, the TNF protons chemical shifts are measured at various temperatures. With the help of a computational study, the geometries of complexation of this host-guest system are identified and their TNF protons chemical shifts calculated. Data analysis led to conclude that in solution two types of conformations are present: the “lateral” one (similar to the structure found in the solid state) and the “longitudinal” one in which the TNF is less engaged inside the host. The proportion of the latter increases with decreasing temperature

Lichens as a source of bio-inspiration for the development of green solvents

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Analysis of the cyanolichen Lichina pygmaea metabolites using in situ DART-MS: from detection to thermochemistry of mycosporine serinol

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Recognition of enantiomers with chiral molecular tweezers derived from (+)- or (−)-usnic acid

International audienceThe synthesis of four stereoisomers of a chiral molecular tweezer using trans-1,2-diaminocyclohexane as spacer and two molecules of usnic acid as pincers is reported. The behavior of these chiral tweezers as chiral complexing agents was evaluated in NMR with various chiral esters containing an electron-poor aromatic ring to allow non-covalent aromatic-aromatic interactions

Lichenic extracts and metabolites as UV filters.

International audienceThree lichen extracts and ten lichenic compounds have been screened for their photoprotective activities. The determination of their Sun Protection Factor (SPF) and Protection Factor-UVA (PF-UVA) values was done in vitro. Among them, a Lasallia pustulata extract and gyrophoric acid exhibited SPF values over 5, which is better than Homosalate (SPF≈4). Their photoprotective properties are only slightly modified after a 2-hours period of irradiation. Salazinic acid and L. pustulata presented characteristics of a UVA booster like the butyl-methoxydibenzoylmethane (Avobenzone) (PF-UVA≈2 vs. 2.8 for Avobenzone). Salazinic acid was a better anion superoxide scavenger than ascorbic acid and none of them exhibited a photosensitizing cytotoxicity by exposing them on HaCaT cells to UVA radiations (photo-irritancy factor PIF<5)

Novel chiral molecular tweezer from (+)-usnic acid.

International audienceA new chiral molecular tweezer was synthesized with (1R,2R)-1,2-diaminocyclohexane as spacer and two molecules of (+)-usnic acid as pincers. The ability of this molecular tweezer to bind 2,4,7-trinitrofluorenone was studied. A charge-transfer complex was formed in which TNF was sandwiched between the two usnic acid units with pi-pi-stacked aromatic interactions