Terpenos e lignanas de Aristolochiaceae
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Data
2010-03-29
Autores
Messiano, Gisele Baraldi [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As espécies brasileiras do gênero Aristolochia possuem similaridade morfológica. Sendo assim, foi desenvolvido um método para a classificação e identificação destas espécies baseado no estudo dos óleos essenciais por CG-EM e quimiometria. Foi também realizado um estudo fitoquímico de duas espécies de Aristolochiaceae, ricas em terpenos e lignanas, e um estudo sintético de lignanas ariltetralônicas e derivados, já que estas lignanas mostraram in vitro uma alta atividade antiplasmódica. Uma das rotas sintéticas estudada foi regiosseletiva, e em quatro etapas dois pares enantioméricos de lignanas ariltetralônicas foram produzidos. As misturas enantioméricas foram testadas in vitro e os resultados mostraram que os pares enantioméricos possuem menor atividade que as lignanas naturais, o que sugere que a atividade antiplasmódica depende das configurações relativa e absoluta dos compostos. A segunda síntese proposta para obtenção de lignanas ariltetralônicas envolveu duas reações de acilação de Friedel-Crafts, e não produziu lignanas, mas seis produtos, incluindo benzofuranos e isocoumarinas. Além disso, lignanas ariltetralônicas foram também alvo de transformações químicas e biotransformações com os fungos Cunninghamella echinulata e Beauveria bassiana, e foram obtidas duas lignanas ariltetralônicas e uma nova lignana ariltetralina [(7'R,8S,8'S)-8,8'-dimetil-3',4',4,5-tetrametoxi-2,7'-ciclolignan-8-ol]. Esta tese também descreve os estudos das investigações de Aristolochia malmeana e Holostylis reniformis. Os compostos foram isolados por técnicas cromatográficas, principalmente CC e CCDP, e foram caracterizados por métodos espectrométricos, particularmente estudos de RMN e medidas de atividade óptica. De H. reniformis foram isoladas quatro lignanas ariltetralônicas, incluindo a inédita ariltetralólica...
The Brazilian Aristolochia species have strong morphological similarities. Thus, a method to classify and identify these species based on analyses of their essential oils by GC-MS and chemometry was developed. Phytochemical study of two Aristolochiaceae species, rich in terpenes and lignans, and syntheses of aryltetralone lignans and derivatives were performed, as these lignans have shown high in vitro antiplasmodial activity. A regioselective synthetic route led to two pairs of enantiomeric aryltetralone lignans in four steps. The antiplasmodial activity of these enantiomeric pairs was evaluated in vitro, and the activity was lower than that of the natural lignans, which suggests that the antiplasmodial activity depends on the relative and absolute configuration of the compounds. A second synthetic route proposed for obtaining the A-B ring portion of aryltetralone lignans, involving two Friedel-Crafts acylation reactions of 1-(3',4'-dimethoxyphenyl)-2-propanol, did not produce the expected aryltetralone lignans, but six products, including benzofurans and isocoumarins. Moreover, chemistry transformations and biotransformations of lignans by fungus (Cunninghamella echinulata and Beauveria bassiana) were studied, from which two aryltetralone lignans and a new aryltetralin lignan [(7'R,8S,8'S)-8,8'-dimethyl-3',4',4,5-tetrametoxy-2,7'-ciclolignan-8-ol] were obtained by the biotransformations. This thesis also describes the results of the investigations of Aristolochia malmeana and Holostylis reniformis. The compounds were isolated by chromatographic techniques, mainly by TLC and CC, and were characterized by spectrometric methods, particularly by NMR experiments and optical rotation measurements. From H. reniformis four lignans were isolated, including a new aryltetralol lignan [rel. (7R,7'R,8S,8'S)-4-hydroxy-3',4',5-trimetoxy-2,7'-cyclolignan-7- ol]. In addition, Anticarsia gemmatalis... (Complete abstract click electronic access below)
The Brazilian Aristolochia species have strong morphological similarities. Thus, a method to classify and identify these species based on analyses of their essential oils by GC-MS and chemometry was developed. Phytochemical study of two Aristolochiaceae species, rich in terpenes and lignans, and syntheses of aryltetralone lignans and derivatives were performed, as these lignans have shown high in vitro antiplasmodial activity. A regioselective synthetic route led to two pairs of enantiomeric aryltetralone lignans in four steps. The antiplasmodial activity of these enantiomeric pairs was evaluated in vitro, and the activity was lower than that of the natural lignans, which suggests that the antiplasmodial activity depends on the relative and absolute configuration of the compounds. A second synthetic route proposed for obtaining the A-B ring portion of aryltetralone lignans, involving two Friedel-Crafts acylation reactions of 1-(3',4'-dimethoxyphenyl)-2-propanol, did not produce the expected aryltetralone lignans, but six products, including benzofurans and isocoumarins. Moreover, chemistry transformations and biotransformations of lignans by fungus (Cunninghamella echinulata and Beauveria bassiana) were studied, from which two aryltetralone lignans and a new aryltetralin lignan [(7'R,8S,8'S)-8,8'-dimethyl-3',4',4,5-tetrametoxy-2,7'-ciclolignan-8-ol] were obtained by the biotransformations. This thesis also describes the results of the investigations of Aristolochia malmeana and Holostylis reniformis. The compounds were isolated by chromatographic techniques, mainly by TLC and CC, and were characterized by spectrometric methods, particularly by NMR experiments and optical rotation measurements. From H. reniformis four lignans were isolated, including a new aryltetralol lignan [rel. (7R,7'R,8S,8'S)-4-hydroxy-3',4',5-trimetoxy-2,7'-cyclolignan-7- ol]. In addition, Anticarsia gemmatalis... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Quimica organica, Óleos essenciais, Lignanas, Organic chemistry, Essential oils, Lignans
Como citar
MESSIANO, Gisele Baraldi. Terpenos e lignanas de Aristolochiaceae. 2010. 128 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Química, 2010.