Quassin?ides (revis?o cr?tica do conhecimento estrutural e bioss?ntese) e quimiossistem?tica de Simaroubaceae

• Author(s): Sim?o, Sheila Marino
• Date: 2020
• Origin: Oasisbr
• Subject(s): Qu?mica; Qu?mica
• Document Type: Master thesis
• Language: Portuguese

Description

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Made available in DSpace on 2020-11-16T12:08:25Z (GMT). No. of bitstreams: 1 1986 - Sheila Marino Sim?o.pdf: 5963701 bytes, checksum: a82218472073ce56778b3f96b75789c7 (MD5) Previous issue date: 1986-05-16

Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq, Brasil)

The quassinoids, micromolecules produced as in is known only by the Simaroubaceae, display high pharmacological potential, surely a result of known structural characteristics. This thesis comprehends and is based in a extensive critical survey of spectral data (NMR1H, M.S. and NMR13C) and of the proposed structures, reported until december of 1984. From proper tabulation and specially elaborated structural classification, these compounds were analyzed, not only on the classical individual way, but chiefly by the comparison among spectral data from neighbour quassinoids, fact that had allowed a new structural interpretation in cases of flagrant incorrection. The systematization of the knowledge of these structural features has the scope of being the bases for the elaboration of a more trustworthy easily computational interpretation method. It also comprehends a chemosystematic approach of the Simaroubaceae by means of determination of skeleton and oxidation evolutionary advancement parameters (EAs and EAo respectively). This approach was made by the complementation of the already mentioned search of the literature data, now embracing other secundary metabolits. This study led, among others, to the conclusion that the genus Harrisonia must not been included in this family. Finally, an exaustive and critical review of the quassinoids biosysnthesis was made and it is noticeable the novel mechanistic racionalization proposition for the formation of C 18 skeleton and of the Brucea antidysenterica "Ketoacid" isolated from the stem bark.

Os quassin?ides, micromol?culas pelo que se sabe produzidas exclusivamente por Simaroubaceae representam alto potencial farmacol?gico, comprovadamente decorrente de peculiaridades conhecidas das caracter?sticas estruturais. Esta tese compreende e apoia-se em extenso levantamento cr?tico dos dados espectrom?ricos (RMN1H, E.M. e RMN13C) e das estruturas propostas, publicados at? dezembro de 1984. A partir de tabula??o apropriada e de classifica??o estrutural especialmente elaborada, essas estruturas puderam ser analisadas, n?o apenas da forma cl?ssica individual, mas sobretudo pela compara??o entre os valores espectrais de quassin?ides afins, o que permitiu nova interpreta??o estrutural para os casos de evidente incorre- ??o. Esta sistematiza??o do conhecimento da estrutura dessas micromol?culas tem por objetivo servir de base para um m?todo mais seguro de interpreta??o, facilmente automatiz?vel. Compreende tamb?m o estudo quimiossistem?tico de Simaroubaceae, por meio de par?metros do avan?o evolutivo ao n?vel de oxida??o molecular (AEo) e de especializa??o do esqueleto (AEe), possibilitado pela complementa??o daquele levantamento, abrangendo desta vez tamb?m outros metab?litos secund?rios, e permitindo a conclus?o, entre outras, de que pelo menos ? luz deste crit?rio o g?nero Harrisonia n?o deveria estar inclu?do nesta fam?lia. E, finalmente, cont?m uma revis?o pormenorizada e tamb?m cr?tica da bioss?ntese dos quassin?ides, onde se destaque as propostas in?ditas de racionaliza??o mecan?stica de forma??o dos quassin?ides C18 e do "Ceto-?cido" isolado de Brucea antidysenterica.