Depuis des décennies, les plantes sont utilisées en pharmacopée traditionnelle pour le soin de plusieurs maladies. Ceci en raison des résistances que présentent certains microorganismes vis-à-vis des produits pharmaceutiques. On notera aussi le manque de moyen financier pour l'accès au soin en médecine moderne. Voilà pourquoi le présent travail porte sur l'extraction, l'isolement, l'élucidation des structures, les transformations chimiques et les tests biologiques des métabolites secondaires des variétés sauvage et cultivée de l'espèce Triumfetta cordifolia A Rich (Tiliaceae). Les chromatographies successives de l'extrait organique des tiges et des feuilles de la variété sauvage ont conduit à l'isolement de quatre produits nouveaux dont deux céramides isolés des tiges et deux triterpènes obtenus des feuilles. Ces composés ont été identifiés à (2R, 6Z)-2-hydroxy-N-[(2S,3S,4R)-1,2,4-trihydroxyhexacosan-2-yl]heptadec-6enamide, {(2R)-N-(1S,2R,3E,6Z,9Z,12Z,15Z)-1-[(beta-D-glucopyranosyloxy)methyl]-2-hydroxy heneicosa-3,6,9,12,15-pentaen-1-yl}-2-hydroxytetradecanamide, 3-O-propanoyl-29-O-triacontanoylstigmasta-5,22-diene-3beta,29-diol et l'acide 2alpha,3beta,19alpha-trimethoxyurs-12-ene-24,28-dioique-24-[(2alpha,3beta)-24,28-bis(beta-D-glucopyranosyloxy)-2-hydroxy-24,28-dioxours-12-en-3-yl] ester. En plus de ces composés, onze autres de structures connues ont été isolés et identifiés à l'acide heptadecanoïque, au glucopyranoside de bêta-sitostérol, à la friedeline, au lupéol, à la bétuline, à l'acide oléanolique, à l'acide maslinique, à l'acide corosolique, au mélange de stigmastérol et bêta-sitostérol, à l'acide heneisanoïque et au trans-tiliroside. De l'extrait organique des tiges et des feuilles de l'espèce cultivée de Triumfetta cordifolia dix produits ont été isolés parmi lesquels trois n'ont pas encore été identifiés, quatre ont été déjà isolés de l'espèce sauvage (mélange de stigmastérol et bêta-sitostérol, glucopyranoside de bêta-sitostérol, triumfettamide) et les trois derniers de structures connues ont été identifiés à l'acide tormentique, à la bêta-carotène et à l'acide 24-hydroxytormentique. Les structures de ces composés ont été élucidées grâce aux données de RMN (1 et 2D) et elles ont été confirmées en comparant ces données à celles décrites dans la littérature. Le stigmastérol a été soumis à plusieurs réactions d'oxydation et en plus des produits obtenus, certains composés isolés en grande quantité ont été soumis au test de cytotoxicité sur une lignée de cellules HT1080. La méthode utilisée est la cytométrie à flux et certaines de ces drogues ont présenté une grande activité cytotoxique bien que induisant à la fois la mort nécrotique et non nécrotique des cellules cancérigènes. L'activité antioxydante des fractions issues du flash des deux plantes et certains composés a été évaluée par la méthode FRAP. Le travail révèle ici le caractère préventif et curatif de nos plantes comestibles ; car ces espèces peuvent bien utiliser contre les stress oxydatifs et les études biologiques pourront être approfondies sur certains composés isolés pour mettre en valeur leur propriétés anticancer / From decade, plants are used in traditional healer to treat many diseases. This could be explained by microorganism pharmaceutical drug resistance. Beside, the poverty limits also access to modern treatment. That is why the present work deals with extraction, isolation, structural elucidation, chemical transformation and biological evaluation of secondary metabolites isolated from the wild and cultivated species of Triumfetta cordifolia A Rich (Tiliaceae). From the organic extract of twigs and leaves of wild T. cordifolia, four new compounds were characterized (two ceramides and two triterpens) by successive chromatography methods and identified as (2R, 6Z)-2-hydroxy-N-[(2S,3S,4R)-1,2,4-trihydroxyhexacosan-2-yl]heptadec-6enamide, {(2R)-N-(1S,2R,3E,6Z,9Z,12Z,15Z)-1-[(beta-D-glucopyranosyloxy)methyl]-2-hydroxy heneicosa-3,6,9,12,15-pentaen-1-yl}-2-hydroxytetradecanamide, 3-O-propanoyl-29-O-triacontanoylstigmasta-5,22-diene-3beta,29-diol et l'acide 2alpha,3beta,19alpha-trimethoxyurs-12-ene-24,28-dioique-24-[(2alpha,3beta)-24,28-bis(beta-D-glucopyranosyloxy)-2-hydroxy-24,28-dioxours-12-en-3-yl] ester acid..These compounds were obtained together with eleven known compounds identified as heptadecanoic acid, beta-sitostérol glucopyranoside, friedelin, lupeol, betulin, oleanolic acid, maslinic acid, corosolic acid, the mixture of stigmasterol and beta sitosterol, heneicosanoic acid and trans-tiliroside. From the organic extract of twigs and leaves of cultivated species, ten products were isolated ; three among of them have not yet been identified, four of them were already obtained from the wild species and the rest were identified as Tormentic acid, beta-carotene and 24-hydroxytormentic acid. The structures of these compounds were determined on the basis of NMR data(1H, 13C, two dimensional NMR analyses), mass spectrometry structure of new compounds were confirmed by chemical transformations while those of known compounds were confirmed by comparison of their physical and spectral data with those reported in the literature and with authentic samples for some of them. Stigmasterol was subjected to different oxidation reactions. The cytotoxic activities of the products and some isolated compounds against human fribosarcoma cell line HT1080 were evaluated. The flow cytometry was used to carry out this assay and some drugs showed good cytotoxic activities although inducing at the same time the apoptopic and necrotic dead of cells. The antioxidant properties of some fractions and compounds were also evaluated by FRAP method. Trans-tiliroside and its fraction showed good antioxidant activity. This work reveals the preventive and curative character of both eatable plants since these species could be used against oxidative stress. Other biological studies could be deepened to highlight the anticancer property of some isolated compounds

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2016-10-10T17:37:26Z No. of bitstreams: 1 texto completo.pdf: 2597735 bytes, checksum: 7f966158e203d7a3e5acd19edd6a1532 (MD5) / Made available in DSpace on 2016-10-10T17:37:26Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2597735 bytes, checksum: 7f966158e203d7a3e5acd19edd6a1532 (MD5) Previous issue date: 2001-03-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Triumfetta semitriloba é uma planta invasora, que apresenta nectários florais e nectários extraflorais localizados na folha e na bráctea. Este trabalho teve como objetivos descrever, de forma comparativa, os nectários de T. semitriloba, estudar a ontogenia dos nectários florais e a senescência dos nectários extraflorais; e realizar uma análise de detecção de aminoácidos no néctar dos respectivos nectários. Foram utilizados cortes seriados em parafina e historesina, os quais foram corados ou submetidos à diferentes testes histoquímicos. Parte das amostras foram analisadas ao microscópio eletrônico de varredura. Os cinco nectários florais de T. semitriloba ocorrem em torno de um curto androginóforo, são constituídos por uma epiderme secretora recoberta por tricomas nectaríferos clavados e um parênquima nectarífero vascularizado. O desenvolvimento dos nectários florais inicia-se em botões com cerca de 1,7mm de comprimento, a partir de divisões anticlinais das células protodérmicas, e divisões em sentidos diversos de células do meristema fundamental e procambiais. Posteriormente, as células protodérmicas se dividem periclinalmente, originando uma estrutura unisseriada constituída por cinco células, onde as três células mais apicais sofrem divisões no sentido anticlinal e oblíquo. A secreção do néctar ocorre em botões em pré-antese, com cerca de 9mm de comprimento. Os nectários extraflorais se localizam nos primeiros pares de dentes basais da lâmina foliar e bracteal. São, estruturalmente, muito semelhantes, constituídos por uma epiderme secretora recoberta por tricomas secretores, delimitada por uma borda epidérmica. Subjacente, encontra-se um parênquima nectarífero e vascularização constituída por floema e xilema. Na análise química de aminoácidos livres proteicos, foram detectados aspartato ou/e triptofano no néctar produzido pelo nectário da bráctea, não sendo detectados aminoácidos nos demais néctares, embora os três néctares de T. semtriloba apresentaram reação positiva à ninhidrina. / Triumfetta semitriloba is a weedy shrub that has floral and extrafloral nectaries on its leaves and bracts. The objectives of this work were to describe comparatively the netaries of T. semitriloba, to study the ontogeny of the floral nectaries and the senescency of the extrafloral nectaries, and to determine the aminoacids which are present in the nectars of the respective nectaries. Serial sections in parafin and historesin were prepared and stained or submitted to histochemistry tests with several purposes. Some samples were observed using a scanning electron microscope. The five nectaries of T. semitriloba are located on the lateral surface of the short androginophore being constituted by a secretory epidermis recovered by clavate nectariferous trichomes and vascularized nectariferous parenchyma. The floral nectary development begin, initially, within the buds wich are 1,7mm long. The development consists of the protodermal cells dividing into anticlinal direction while the ground meristem and procambial cells dividing into several directions. Afterwards, the protodermic cells divide periclinally, giving rise to an unisseriated structure with five cells. The three most apical cells divide into anticlinal and oblique directions. The nectar secretion occurs in pre-anthesis buds which are 9mm long. The extrafloral nectaries are located in the first basal teeth pairs of the foliar and bracteal blades. They are structurally similar, constituted by a secretory epidermis which is recovered by secretory trichomes, also they are delimited by an epidermal margins. Immediately below there are a nectariferous parenchyma and vascular system formed by phloem and xylem. In the free proteic aminoacid chemical analysis, aspartate and/or tryptophan were detected in the nectar yielded by the bracteal nectaries. However, it was not detected any aminoacid on the other nectars, although the three nectars of T. semtriloba had shown ninhidrin positive reactions. / Dissertação importada do Alexandria