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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudo químico dos fungos endofíticos Phomopsis sp., Guignardia sp., Aspergillus niger e Aspergillus sp., associados à espécie vegetal Hancornia speciosa (Apocinaceae) / CHEMICAL INVESTIGATION OF THE ENDOPHYTIC FUNGUS PHOMOPSIS SP., GUIGNARD SP., ASPERGILLUS NIGER AND ASPERGILLUS SP., PLANT SPECIES ASSOCIATED WITH HANCORNIA SPECIOSA (APOCINACEAE).

Santos, Mário Ferreira Conceição 16 February 2011 (has links)
This work describes the isolation of endophytic fungi from plant species Hancornia speciosa and led to the isolation of 14 pure strains. Of which 4 were selected for the chemical study. The chemical study allowed identied 12 substances isolated from fungi Phomopsis sp., Guignardia sp., Aspergillus niger e Aspergillus sp., grown in different culture medium. The crude extracts of fungus Phomopsis sp., grown in PDB medium led to isolation of five compounds, 5- methylmelein, nectriapyrone, succnic acid, 5-hydroxylmethylmelein and a diketopiperazine. Already when the same fungus was grown in ME medium, led to isolation of two compounds, tyrosol and tryptofol. The crude extract of Guignardia sp grown in ME medium led to isolation of compound salicylic acid, which has a plant for ecological importance.The crude extract of Aspergillus niger, grown in PDB medium led to isolation of compounds pyrophen and nigragillin. Already when the same fungus was grown in ME medium, led to isolation of compound itaconic acid. And of crude extract of Aspergillus sp., grown in ME medium was identification of their major compound kojic acid, which was quantified by HPLC in the crude extract (0.7 mg/g of crude extract). O crude extract was tested for its antioxidant activity with DPPH, NO. and H2O2, and exhibited significantly potent inhibition of NO (IC50 de 150 μg/mL) production, showed taht this fungi it owns big biotchenology potential. The structures of these substances were established by spectroscopic methods, including the application of bidimensional NMR techniques, mass spectrum and comparison with published data. / Este trabalho descreve o isolamento de fungos endofíticos da espécie vegetal Hancornia speciosa, o qual conduziu a 14 linhagens puras, dos quais quatro foram selecionados para o estudo químico. O estudo químico possibilitou foi identicar 12 substâncias, isoladas dos fungos Phomopsis sp., Guignardia sp., Aspergillus níger e Aspergillus sp., cultivados em diferentes meios de culturas. O extrato bruto do fungo Phomopsis sp cultivado no meio liquido PBD levou ao isolamento de cinco compostos, 5- metilmeleína, nectapirona, ácido succínico, 5-hidroxilmetilmeleína e uma dicetopiperazina. Já o mesmo fungo quando cultivado no meio líquido-ME, levou ao isolamento de dois compostos, tirosol e triptofol. O estudo do extrato bruto de Guignardia sp., cultivado no meio liquido ME conduziu ao isolamento do composto ácido salicílico, o qual tem um importancia ecológica para planta. O extrato bruto do fungo Aspergillus niger cultivado no meio liquido PBD levou ao isolamento dos compostos pirofen e nigragillin. Já o mesmo fungo quando cultivado em extrato de malte, levou ao isolamento do ácido itacônico. E do extrato bruto do fungo Aspergillus sp., cultivado no meio liquido PBD foi identificada a substância majoritária ácido kójico, a qual foi quantificada por CLAE no extrato bruto (0,7g/ g de extrato bruto). O extrato desse fungo foi testado quanto a sua atividade antioxidante com DPPH, NO. , e H2O2, e mostrou uma forte atividade de inibição da produção de NO (IC50 de 150 μg/mL), indicando que este fungo possui grande potencial biotecnológico. As estruturas das substâncias foram determinadas por métodos espectrométricos, incluindo RMN bi-dimensional, espectros de massas e comparação com a literatura.

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