Fungos endofíticos associados à Platonia insignis Mart.: estudo dos metabólitos voláteis e não voláteis de Diaporthe hongkongensis e Phyllosticta elongata
Carregando...
Data
2019-12-16
Autores
Costa, Isabella Cristhina Gonçalves
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os fungos endofíticos, representam uma fonte promissora na descoberta de produtos naturais. Estes endófitos têm se revelado pela alta capacidade na produção de diversas classes de metabólitos secundários com uma ampla variedade de atividades biológicas, tais como: antimicrobiana, citotóxica, antioxidante, ansiolítica e inseticida. Estas observações motivaram o desenvolvimento do presente estudo, o qual visou a prospecção química e biológica dos fungos endofíticos associados à Platonia insignis Mart. O isolamento dos fungos endofíticos resultou em dezoito linhagens puras, sendo estes cultivados em meio líquido de MDB, para obtenção dos respectivos extratos brutos. Estes foram avaliados quanto ao perfil químico e biológico, os quais demonstram ser promissores para produção de substâncias bioativas. A prospecção inicial conduziu a seleção de dois fungos endofíticos, identificados como Diaporthe hongkongensis e Phyllosticta elongata para desenvolvimento do trabalho. Duas abordagens foram aplicadas a fim de verificar a influência da composição nutricional frente a produção metabólica de D. hongkongensis e P. elongata: cultivo em meio de MDB e cultivo em meio sólido de milho. O estudo de D. hongkongensis, cultivado em MDB, resultou no isolamento de uma dicetopiperazina, ariletilamida, acetiltriptamina e o acetato de metila-[2-oxo-2-(feniletilamino)], sendo o primeiro relato de isolamento deste composto como produto natural. Do cultivo deste endófito, em meio de milho, foram isolados o alternariol, um éster de ácido graxo e 4 esteroides, que se encontram em fase de determinação estrutural. O cultivo de P. elongata em meio MDB, conduziu ao isolamento de três dicetopiperazinas, uma isoflavona (daidzeína), tirosol, ácido 4-hidroxibenzoico e dois meroterpenoides. A partir do cultivo desta linhagem em meio de milho, foram isolados os enantiômeros enantio-flavipesina B e flavipesina B e novamente o meroterpeno guignardona A. As substâncias flavipesina B e guignardona A foram testadas frente a bactérias resistentes e à cepa de Trypanossoma cruzi, respectivamente, as quais apresentaram atividade significativas. Estes dois endófitos também foram investigados quanto à produção de compostos orgânicos voláteis (COVs), em diferentes condições de cultivo, no qual utilizou-se dois meios de cultivo sólido, sendo o BDA e o milho, e dois períodos de incubação distintos (7 e 14 dias). Os resultados obtidos mostraram que estes fungos representam uma fonte promissora de COVs, e que mudanças nas condições de cultivo, bem como experimentos de co-cultivo podem levar a produção diferentes COVs. Portanto, esses resultados ressaltam a importância do estudo da diversidade metabólica de fungos endofíticos, sugerindo um papel ecológico destes endófitos quando associados à espécie vegetal. Além disso, este é o primeiro relato de estudo químico de D. hongkongensis e P. elongata.
Endophytic fungi represent a promising source for the discovery of natural products. These endophytes have been shown to be highly capable of producing various classes of secondary metabolites with a wide variety of biological activities such as antimicrobial, cytotoxic, antioxidant, anxiolytic and insecticide. These observations motivated the development of the present study, which aimed at the chemical and biological prospecting of endophytic fungi associated with Platonia insignis Mart. The isolation of endophytic fungi resulted in eighteen pure strains, which were cultivated in liquid medium of PDB, to obtain the respective crude extracts. These extracts were evaluated for chemical and biological profile, which show promise for bioactive substances production. The initial prospecting led to the selection of two endophytic fungi, identified as Diaporthe hongkongensis and Phyllosticta elongata to develop the work. Two approaches were applied to verify the influence of nutritional composition on the metabolic production of D. hongkongensis and P. elongata: cultivation in PDB medium and cultivation in solid corn medium. The study of D. hongkongensis grown in PDB resulted in the isolation of a diketopiperazine, arylethylamide, acetyltryptamine and methyl [2-oxo-2- (phenylethylamino)] acetate, being the first report of isolation of this compound as a natural product. From the cultivation of this endophyte in corn medium, alternariol, a fatty acid ester and four steroids, which are in the structural determination phase, were isolated. Cultivation of P. elongata in PDB medium led to the isolation of three diketopiperazines, one isoflavone (daidzein), tyrosol, 4-hydroxybenzoic acid and two meroterpenoids. From the cultivation of this strain in corn medium, the enantiomers enanti-flavipesin B and flavipesin B were isolated and again the meroterpene guignardone A. The compounds flavipesin B and guignardone A were tested against resistant bacteria and Trypanosoma cruzi strain, respectively, which showed significant activity. These two endophytes were also investigated for the production of volatile organic compounds (VOCs) under different cultivation conditions, using two solid culture media, BDA and maize, and two distinct incubation periods (7 and 14 days). The results showed that these fungi represent a promising source of VOCs, and that changes in cultivation conditions as well as co-cultivation experiments can lead to different production of VOCs. Therefore, these results underscore the importance of studying the metabolic diversity of endophytic fungi, suggesting an ecological role of these endophytes when associated with plant species. Also, this is the first chemical study report of D. hongkongensis and P. elongata.
Endophytic fungi represent a promising source for the discovery of natural products. These endophytes have been shown to be highly capable of producing various classes of secondary metabolites with a wide variety of biological activities such as antimicrobial, cytotoxic, antioxidant, anxiolytic and insecticide. These observations motivated the development of the present study, which aimed at the chemical and biological prospecting of endophytic fungi associated with Platonia insignis Mart. The isolation of endophytic fungi resulted in eighteen pure strains, which were cultivated in liquid medium of PDB, to obtain the respective crude extracts. These extracts were evaluated for chemical and biological profile, which show promise for bioactive substances production. The initial prospecting led to the selection of two endophytic fungi, identified as Diaporthe hongkongensis and Phyllosticta elongata to develop the work. Two approaches were applied to verify the influence of nutritional composition on the metabolic production of D. hongkongensis and P. elongata: cultivation in PDB medium and cultivation in solid corn medium. The study of D. hongkongensis grown in PDB resulted in the isolation of a diketopiperazine, arylethylamide, acetyltryptamine and methyl [2-oxo-2- (phenylethylamino)] acetate, being the first report of isolation of this compound as a natural product. From the cultivation of this endophyte in corn medium, alternariol, a fatty acid ester and four steroids, which are in the structural determination phase, were isolated. Cultivation of P. elongata in PDB medium led to the isolation of three diketopiperazines, one isoflavone (daidzein), tyrosol, 4-hydroxybenzoic acid and two meroterpenoids. From the cultivation of this strain in corn medium, the enantiomers enanti-flavipesin B and flavipesin B were isolated and again the meroterpene guignardone A. The compounds flavipesin B and guignardone A were tested against resistant bacteria and Trypanosoma cruzi strain, respectively, which showed significant activity. These two endophytes were also investigated for the production of volatile organic compounds (VOCs) under different cultivation conditions, using two solid culture media, BDA and maize, and two distinct incubation periods (7 and 14 days). The results showed that these fungi represent a promising source of VOCs, and that changes in cultivation conditions as well as co-cultivation experiments can lead to different production of VOCs. Therefore, these results underscore the importance of studying the metabolic diversity of endophytic fungi, suggesting an ecological role of these endophytes when associated with plant species. Also, this is the first chemical study report of D. hongkongensis and P. elongata.
Descrição
Palavras-chave
Platonia insignis Mart., Fungos endofíticos, Diaporthe hongkongensis, Phyllostica elongata, Endophytic fungi