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Master's Dissertation
DOI
10.11606/D.59.2011.tde-27112011-193019
Document
Author
Full name
Letícia Bazeia Lima
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2011
Supervisor
Committee
Cardoso, Carmen Lúcia (President)
Debonsi, Hosana Maria
Januário, Ana Helena
Title in Portuguese
Triagem da atividade antioxidante e anticolinesterásica de extratos naturais: seleção e estudo químico biomonitorado de Streptomyces sp. e de Psychotria carthagenensis
Keywords in Portuguese
Determinação estrutural
Ensaios
Extratos naturais
Produtos naturais
Abstract in Portuguese
Esse trabalho descreve o estudo monitorado de extratos de origem microbiológica e vegetal. Com o objetivo de identificar compostos com atividade antioxidante e/ou inibidores da enzima acetilcolinesterase em extratos de origem microbiológica e vegetal do cerrado brasileiro, uma triagem de atividade foi realizada utilizando ensaios simples e rápidos. Nessa triagem dois extratos promissores foram selecionados para os estudos de identificação dos compostos responsáveis pela atividade inicial. O trabalho de purificação foi iniciado com a fração em acetato de etila do extrato etanólico da actinobactéria-36 (50PL), Streptomyces sp., fermentado em meio de canjica amarela que apresentou atividade nos dois ensaios realizados. As atividades antioxidante e anticolinesterásica são relatadas pela primeira vez para essa actinobactéria. Nesse estudo foram identificados dois compostos, o éster metílico do ácido cis-6, cis-8 octadecadienóico e o tetradecanal. Da espécie Psychotria carthagenensis, uma planta da família Rubiaceae, foram objeto de estudo as frações hexânica e acetato de etila oriundas do extrato etanólico das folhas, o extrato hexânico das folhas e o extrato etanólico dos caules. A espécie P. cartahgenensis foi investigada quanto à presença de alcalóides uma vez que é utilizada juntamente com as espécies Psychotria viridis e Banisteriopsis caapi no preparo de uma bebida alucinógena conhecida como ayahuasca. A partir dos extratos etanólicos das sementes, caules e folhas foi realizada uma extração ácido-base resultando em frações ricas em compostos nitrogenados. As frações de alcalóides totais foram analisadas em TLC e revelador específico, o cloro-iodoplatinado, evidenciando a presença de alcalóides. As frações foram analisadas por EM (desreplicação) resultando na identificação de 5 compostos nitrogenados.
Title in English
Screening of antioxidant and anticholinesterase activity of natural extracts: selection and bioassay-guided chemical study of Streptomyces sp. and Psychotria carthagenensis
Keywords in English
Assay
Natural extracts
Natural products
Structural determination
Abstract in English
This work describes the monitored study of extracts from microbiological and plant origin. In order to identify compounds with antioxidant action and/or inhibitors of acetylcholinesterase enzyme in extracts of microbial and plants of the Brazilian Cerrado vegetation, screening for these activities was performed using simple and rapid tests. From this screening, two promising extracts were selected for identification of the compounds responsible for the initially observed activity. Purification was started with the ethyl acetate fraction in the ethanol extract of actinobacteria-36 (50PL), Streptomyces sp., fermented in a yellow hominy culture medium that displayed activity in both tests. Antioxidant and anticholinesterase activities are reported for this actinobacteria for the first time. Two compounds were identified, namely 6(Z),8(Z)-octadecadienoic acid, methyl ester and tetradecanal. The hexane and ethyl acetate fractions of the ethanol extract of the leaves as well as the ethanol extract of the stems from the Psychotria carthagenensis species, a plant of the Rubiaceae family, were studied. This species was investigated for the presence of alkaloids, because it is used together with the species Psychotria viridis and Banisteriopsis caapi in the preparation of a hallucinogenic drink known as ayahuasca. Acid-base extractions of the ethanol extracts of the seeds, stems, and leaves of this plant were carried out, resulting in fractions rich in nitrogen compounds. The total alkaloids fractions were analyzed by TLC and specific revealing with chlorine-iodoplatinate, which evidenced the presence of alkaloids. The fractions were analyzed by MS (derreplication), which allowed for identification of five nitrogen compounds.
 
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Publishing Date
2012-01-10
 
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