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Doctoral Thesis
DOI
https://doi.org/10.11606/T.60.2013.tde-25062013-160339
Document
Author
Full name
Henrique Pereira Ramos
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2013
Supervisor
Committee
Said, Suraia (President)
Pietro, Rosemeire Cristina Linhari Rodrigues
Bauab, Taís Maria
Carvalho, Ivone
Debonsi, Hosana Maria
Title in Portuguese
Obtenção e identificação de metabólitos secundários com atividade antiparasitária produzidos pelo fungo endofítico Arthrinium state of Apiospora montagnei Sacc
Keywords in Portuguese
Arthrinium state of Apiospora montagnei
Atividade antileishmania
Atividade esquistossomicida
Fungo endofítico
Abstract in Portuguese
Estimativas apontam haver no mundo 12 milhões de pessoas infectadas por diferentes espécies de Leishmania, estando 350 milhões de pessoas em situação de risco. A leishmaniose é um grave problema de saúde pública mundial e entretanto não há tratamentos eficientes para o controle desta doença. Fungos endofíticos são fontes promissoras de metabólitos secundários bioativos e isso se deve em parte a sua estreita interação com as plantas hospedeiras. Extratos de culturas do fungo Arthrinium state of Apiospora montagnei Sacc., isolado como endofítico de Smallanthus sonchifolius (yacon), demonstrou em estudos anteriores ser uma fonte promissora de metabólitos secundários distintos, apresentando atividades antibacteriana, antifúngica, citotóxica para linhagens de células tumorais e antiparasitária. Devido a elevada atividade antileishmania detectada, culturas do fungo Arthrinium state of Apiospora montagnei Sacc. foram realizadas em duas etapas distintas de cultivo. Obteve-se 1,47g de extrato AcOEt, o qual foi posteriormente fracionado por cromatografia líquida a vácuo. As frações resultantes foram fracionadas por cromatografia líquida clássica e cromatografia líquida de alta eficiência em escala preparativa. Dez substâncias foram isoladas, oito a partir de frações bioativas e suas estruturas foram elucidadas por análises de experimentos de RMN 1D: RMN 1H, RMN 13C e DEPT e 2D: COSY 1H-1H, HMQC 1H-13C e HMBC 1H-13C. As substâncias I e III apresentaram atividade esquistossomicida, causando 100% de morte nos parasitas quando avaliadas nas concentrações de 200 e 50 ?g/mL, respectivamente. Análises por microscopia eletrônica de varredura mostraram alterações morfológicas como o possível mecanismo de ação destas substâncias. As substâncias VII e IX, que parecem ser inéditas na literatura, apresentaram atividade antileishmania com valores de CI50 de 12,54 e 3,04 ?g/mL frente Leishmania braziliensis e 8,78 e 2,87 ?g/mL frente L. chagasi, respectivamente. O presente trabalho corrobora fungos endofíticos como uma fonte promissora, ainda pouco explorada, de novos metabólitos com atividade antileishmania e esquistossomicida.
Title in English
Isolation and identification of secondary metabolites with antiparasitic activity from the endophytic fungus Arthrinium state of Apiospora montagnei Sacc
Keywords in English
Antileishmanial activity
Arthrinium state of Apiospora montagnei
Endophytic fungi
Schistosomicidal activity
Abstract in English
Leishmaniais affects over 12 million people and 350 million people in 88 countries are at risk. Recognised as a major public health problem, leishmaniasis causes high morbidity and mortality levels. There are currently no vaccines and the available chemotherapy against leishmaniasis still suffers from high toxicity, serious side effects, require long-term treatment and present clinical resistance. Endophytic fungi are promising source of bioactive secondary metabolites due in part of their close interaction with the host plants. In previous studies the fungus Arthrinium state of Apiospora montagnei Sacc., isolated as endophytic fungus from Smallanthus sonchifolius (yacon), demonstrated to be a promising source of secondary metabolites with antibacterial, antifungal, antitumoral and antileishmanial activities. In view of the high antileishmanial activity previously detected, in the present study the endophytic fungus Arthrinium state of Apiospora montagnei was cultivated in a liquid medium under standardized culture condition, yielding 1.47 g of EtOAc extract, which was further fractionated by vacuum liquid chromatography, and the resulting fractions fractionated by liquid chromatography and high performance liquid chromatography. Ten compounds were isolated, nine from bioactive fractions. Their chemical structures were elucidated by analysis of NMR experiments 1D: RMN 1H, RMN 13C and DEPT and 2D: COSY 1H-1H, HMQC 1H-13C and HMBC 1H-13C. The substances I and III showed schistosomicidal activity, causing 100% death of the parasites when evaluated at concentrations of 200 and 50 ?g/mL, respectively. Analysis by scanning electron microscopy suggested that morphological changes are possibly the mechanism of action of these substances. Two new compounds, VII and IX, showed antileishmanial activity with IC50 values of 12.54 and 3.04 ?g/mL against Leishmania braziliensis and 8.78 and 2.87 ?g/mL against L. chagasi, respectively. The present work supports endophytic fungi as a promising source of new metabolites underexplored with antileishmanial and schistosomicidal activity.
 
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Publishing Date
2015-04-10
 
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