Effet protecteur des polyphénols de la verveine odorante dans un modèle d'inflammation colique chez le rat

La consommation de polyphénols, micronutriments largement répandus dans lesaliments d origine végétale, a été associée à la diminution du risque de développement denombreuses pathologies telles que maladies cardiovasculaires, maladies neurodégénérativesou cancers. Cet effet des polyphénols s explique en partie par leurs propriétés antioxydanteset anti-inflammatoires. Du fait de leur faible absorption au niveau de l intestin grêle, lespolyphénols sont présents en grande quantité dans le côlon où ils peuvent exercer cespropriétés. L inflammation intestinale fait interagir le système immunitaire intestinal avecde nombreux facteurs environnementaux et est fréquemment associée à une augmentationdu stress oxydant via la production d espèces réactives de l oxygène par les cellulesimmunitaires. De nombreuses études ont montré, sur des modèles animaux d inflammationintestinale, les effets protecteurs de certains polyphénols. La verveine odorante (Aloysiatriphylla (L Hérit.) Britton) est une plante médicinale connue pour ses vertus thérapeutiquesdigestives et anti-spasmodiques et couramment consommée en infusion. L infusé deverveine odorante contient de grandes quantités de polyphénols (acides phénoliquescomplexes et dérivés de flavones) et ses propriétés antioxydantes ont été mises en évidenceaussi bien in vitro qu in vivo.L objectif de cette thèse a donc été d'évaluer l effet d une consommation préventived un infusé de verveine odorante à dose nutritionnelle (40 g/l et 4 g/l) sur le développementd une inflammation intestinale modérée chez le rat. Des rats Wistar ont consommé commeboisson l infusé de verveine seul pendant deux semaines puis associé à un agentinflammatoire, le sulfate de dextran sodique (DSS), à 4% pendant 7 ou 9 jours. L effet de laverveine a été évalué sur différents paramètres cliniques (diarrhée, saignements rectaux,poids corporel), marqueurs de l inflammation (longueur du côlon, score histologique,activité myéloperoxydase, cytokines) et du stress oxydant (peroxydation lipidique,glutathion, défenses antioxydantes enzymatiques). Les cellules immunitaires ont étéidentifiées dans le sang ainsi que dans les structures lymphoïdes secondaires par cytométrieen flux. Enfin l étude du métabolisme des polyphénols en situation inflammatoire ou non aété initiée par l analyse de l excrétion urinaire des dérivés polyphénoliques.Lors d une inflammation de 7 jours, la consommation préventive d infusé deverveine à 40 g/l et 4 g/l retarde l apparition de diarrhée et de saignements rectaux, limite larétraction du côlon et la diminution de la prise de poids des rats. Malgré l absence d effetsur l activité myéloperoxydase, l infusé à 40 g/l atténue les altérations histologiques de lamuqueuse colique induites par l inflammation. L infusé à 4 g/l stimule l activité de lasuperoxyde dismutase et réduit la peroxydation lipidique. Les deux infusés modulent lespopulations de cellules immunitaires dans les structures lymphoïdes secondaires (ganglionsmésentériques et plaques de Peyer), en particulier les lymphocytes B et les lymphocytes Tcytotoxiques. L excrétion urinaire des polyphénols de la verveine est faible et n'est pasaffectée par l'inflammation. Lors d une inflammation de 9 jours, les deux infusés limitentl augmentation d activité de la myéloperoxydase. Seul l infusé à 40 g/l limite la rétractiondu côlon, stimule l activité de la glutathion réductase et diminue les taux d IL-6 et deTNF-a. Ainsi, nous avons montré qu une consommation préventive d un infusé de verveineodorante offre des effets protecteurs lors de l inflammation intestinale en agissant àdifférents niveaux. L exploration des voies de signalisation impliquées pourrait permettre demieux comprendre les effets protecteurs de cette boisson de consommation courante.Polyphenols are micronutrients widely distributed in foods of plant origin and theirconsumption has been associated with a decreased risk of various pathologies such ascardiovascular diseases, neurodegenerative diseases and cancer. This effect of polyphenolsis sustained by their antioxidative and anti-inflammatory properties. Due to their poorabsorption in the small intestine, high amounts of polyphenols reach the colon where theycan exert such properties. Intestinal inflammation results from an interaction between gutimmunity and various environmental factors and is frequently associated with an increase ofoxidative stress. Numerous studies have shown protective effects of polyphenols in animalcolitis models. Lemon verbena (Aloysia triphylla (L Hérit.) Britton) is a medicinal herbknown for its digestive and antispasmodic properties and is widely consumed as an infusion.Lemon verbena infusion contains large amounts of polyphenols (complex phenolic acidsand flavone glycosides) and their antioxidative properties have been shown in vitro and invivo.The aim of the present thesis was to evaluate the effects of a preventive consumptionof lemon verbena infusion at nutritional doses (40 g/l and 4 g/l) on the development of amoderate colitis in the rat. Wistar rats ingested lemon verbena infusion alone as a drink fortwo weeks and then associated with the inflammatory agent dextran sulfate sodium (DSS) at4% for 7 or 9 days. Effects of lemon verbena were evaluated on several clinical parameters(diarrhoea, rectal bleeding, body weight), inflammatory markers (colon length, histologicalscore, myeloperoxidase activity, cytokines) and oxidative stress markers (lipid peroxidation,glutathione, antioxidative enzymatic defenses). Immune cells were identified in blood andgut associated lymphoid structures using flow cytometry. Moreover, the study of polyphenolmetabolism was initiated by the analysis of urinary polyphenol metabolites in healthy andcolitis rats.During a 7 days inflammation, the preventive consumption of lemon verbenainfusion at 40 g/l and 4 g/l delays apparition of diarrhoea and rectal bleeding, limits thecolon length reduction and the decrease of body weight gain. Despite no effect onmyeloperoxidase activity, the 40 g/l infusion attenuates colonic mucosa alterations due tothe colitis. The 4 g/l infusion increases superoxide dismutase activity and reduces lipidperoxidation. Both infusions modulate immune cell populations in gut associated lymphoidstructures (mesenteric lymph nodes and Peyer patches), especially B cells and cytotoxic Tcells. Urinary excretion of lemon verbena polyphenols is low and not modified byinflammation. During a 9 days inflammation, both lemon verbena infusions limitmyeloperoxidase increase. Only the 40 g/l infusion reduces colon retraction, increasesglutathione reductase activity and reduces colonic IL-6 and TNF-a levels.Thus, we have shown that the preventive consumption of a lemon verbena infusionprovided protection against intestinal inflammation at different levels. Exploration ofvarious signalling pathways could allow better insight into the protective effects of thiscommon beverage.CLERMONT FD-Bib.électronique (631139902) / SudocSudocFranceF

Les troubles féminins de la puberté à la ménopause (phytothérapie et conseils à l'officine)

A partir de la puberté et jusqu'après la ménopause, les femmes doivent faire face à des situations souvent perturbantes pour leur quotidien comme le syndrome prémenstruel, les troubles de la menstruation, la grossesse, l'allaitement, la ménopause, les troubles de la libido, la cystite, les jambes lourdes ou l'ostéoporose. La minceur et la beauté sont également une priorité pour bon nombre d'entre elles. Ce travail bibliographique, mettant en évidence les principales plantes utiles chez la femme, constitue une aide pour le pharmacien dans sa pratique officinale.CLERMONT FD-BCIU-Santé (631132104) / SudocLYON1-BU Santé (693882101) / SudocSudocFranceF

Prise en charge des douleurs rhumatologiques et des traumatismes sportifs par les huiles essentielles

L'aromathérapie connaît aujourd'hui un intérêt de plus en plus important chez les personnes souhaitant se soigner par des médecines dites "naturelles" ou "douces". Une utilisation responsable et efficace des huiles essentielles repose sur deux piliers : la connaissance des plantes aromatiques d où sont extraites les huiles essentielles et les études issues de la recherche scientifique qui sont publiées et reconnues. Dans un premier temps, cet ouvrage présente les généralités concernant les huiles essentielles (composition, modes d'obtention, critères de qualité, propriétés, voies d'administration, précautions d'emploi, réglementation). La deuxième partie est consacrée à la prise en charge de la douleur en rhumatologie et dans les traumatismes sportifs (présentation de monographies de plantes aromatiques, publication scientifiques et conseils d utilisation des huiles essentielles s'appuyant sur ces données scientifiques).CLERMONT FD-BCIU-Santé (631132104) / SudocLYON1-BU Santé (693882101) / SudocSudocFranceF

Screening and Characterization of Antiglycoxidant Anthocyanins from Vaccinium myrtillus Fruit Using DPPH and Methylglyoxal Pre-Column HPLC Assays

International audienceVaccinium myrtillusfruit (bilberry) is well known for its high richness in anthocyanins,which may be responsible for its preventive effects on several oxidative and carbonyl stress-relatedpathologies. However, limited data are available regarding the antioxidant and antiglycativecontributions of its constituents. Spectrometric analyses were performed to evaluate anthocyanincontent, radical scavenging and antiglycative properties of an anthocyanin-rich extract from bilberries.Additionally, original DPPH and methylglyoxal pre-column HPLC methods were instigated to allowstraightforward identification of the main contributors to radical and carbonyl trapping effects.Finally, representative pure anthocyanins were evaluated using classical DPPH and antiglycationassays. Delphinidin, petunidin and cyanidin glycosides were identified as the most effective radicalscavenging constituents in both HPLC and spectrometric DPPH evaluations. Potent antiglycativeactivities were also assessed for cyanidin, delphinidin and petunidin glucosides as attested by theirrespective IC50values of 114.2±7.8, 130.5±2.8, and 132.4±3.7μM. Interestingly, methylglyoxalspiking evaluation demonstrated that all bilberry anthocyanins exerted noticeable and comparableα-dicarbonyl trapping effects. Anthocyanins can be regarded as potent antiglycoxidant agents thatmight account for some health benefits of bilberries consumption. Besides, significant differences intheir contributions were successfully highlighted by the employed pre-column HPLC assays

Impact of Simulated Gastrointestinal Conditions on Antiglycoxidant and α-Glucosidase Inhibition Capacities of Cyanidin-3-O-Glucoside

International audienceCyanidin-3-O-glucoside (C3G) is a widespread anthocyanin derivative, which has been reported in vitro to exert potent antioxidant, antiglycation and α-glucosidase inhibition effects. Nevertheless, the physiological relevance of such properties remains uncertain considering its significant instability in gastrointestinal conditions. A simulated digestion procedure was thus instigated to assess the influence of gastric and intestinal media on its chemical integrity and biological activities. HPLC analyses of digested C3G samples confirmed the striking impact of intestinal conditions, as attested by a decomposition ratio of 70%. In contrast, with recovery rates of around 90%, antiglycation, as well as DPPH and ABTS scavenging assays, uniformly revealed a noteworthy persistence of its antiglycoxidant capacities. Remarkably, a prominent increase of its α-glucosidase inhibition activity was even observed after the intestinal phase, suggesting that classical in vitro evaluations might underestimate C3G antidiabetic potential. Consequently, the present data provide novel and specific insights on C3G’s digestive fate, suggesting that the gastrointestinal tract does not profoundly affect its positive action on oxidative and carbonyl stresses. More specifically, it also tends to support its regulating effects on postprandial hyperglycemia and its potential usefulness for diabetes management

Stability and Antiglycoxidant Potential of Bilberry Anthocyanins in Simulated Gastrointestinal Tract Model

International audienceAnthocyanins from Vaccinium myrtillus fruits have been reported in vitro to exert potent radical scavenging and antiglycation activities. However, the physiological relevance of such properties remains unclear given the potential susceptibility of anthocyanin derivatives to digestive conditions. A simulated gastrointestinal tract model was thus implemented to assess the impact of gastric and intestinal phases on the chemical integrity of bilberry anthocyanins and their antiglycoxidant effects. Results demonstrated that the investigated activities as well as total and individual anthocyanin contents were marginally affected by gastric conditions. By contrast, with recoveries ranging from 16.1 to 41.2%, bilberry anthocyanins were shown to be highly sensitive to the intestinal phase. Of major interest, a much better preservation was observed for radical scavenging and antiglycation activities as attested by recovery rates ranging from 79.1 to 86.7%. Consistently with previous observations, the present study confirms the moderate bioaccessibility of anthocyanin constituents. It does however provide valuable information supporting the persistence of substantial radical scavenging and antiglycation activities at each step of the digestion process. Taken together, these data indicate that digestive conditions might not abolish the potential positive effects of bilberry consumption on both oxidative and carbonyl stresses

Bioavailability of lemon verbena (Aloysia triphylla) polyphenols in rats: impact of colonic inflammation

International audienceLemon verbena (Aloysia triphylla) infusion, a widely consumed herbal tea, contains significant amounts of polyphenols such as flavone diglucuronides and phenylpropanoid glycosides (mainly verbascoside). We have recently shown that lemon verbena infusion offers beneficial effects against dextran sodium sulphate (DSS)-induced colonic inflammation in rats. The present study aimed to evaluate the bioavailability and intestinal absorption of polyphenols derived from lemon verbena infusion in both healthy and colitic rats. For this purpose, lemon verbena infusion was given to rats ad libitum for 14d, and then 4% DSS was added to the infusion for 7d. Before and after DSS administration, 24h urinary excretion of polyphenols was determined. Flavones were excreted in the urine as conjugated aglycones, and their excretion was not significantly altered by colonic inflammation. Only trace amounts of verbascoside were excreted in the urine, but various metabolites (hydroxycinnamic acids) were detected. The urinary excretion of hydroxycinnamic acids, particularly that of caffeic acid, increased after DSS administration (P<0 center dot 05). Only flavone aglycones (luteolin and diosmetin) were excreted in the faeces in small proportions (3 center dot 2% of ingested flavones). Intestinal absorption of lemon verbena polyphenols was examined using an in situ intestinal perfusion model. Intestinal absorption of verbascoside and flavone diglucuronides did not significantly differ between the healthy and colitic rats. Collectively, these results show that intestinal absorption and urinary excretion of lemon verbena flavone diglucuronides were not altered by colonic inflammation, but that urinary excretion of hydroxycinnamic acids derived from verbascoside was affected in a colitic situation