Alcaloides indólicos das partes aéreas de psychotria sp.(rubiaceae) e síntese de tiohidantoínas e tioureias derivadas de aminoácidos e do r-(+)-limoneno
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2013-05-03
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Universidade Federal de Goiás
Resumo
The use of natural products and their synthetic derivatives has been a relevant
strategy in the development of novel medicines. Phytochemical studies and synthesis of
natural-product-based libraries are primordial in the search for therapeutic agents.
Previous phytochemical studies of genus Psychotria (Rubiaceae) have resulted in the
identification of polypyrrolidine indole and monoterpenoid indole alkaloids, which
present a broad range of biological activities, such as antifungal and inhibition of
monoamine oxidases (MAOs) A e B, that are related to neurodegenerative diseases.
This study aims to evaluate the phytochemical composition of the aerial parts of
Psychotria sp. collected in Brazilian Cerrado. Fractionation of the crude extract by
column chromatography on silica gel and Sephadex led to isolation of three known
indole alkaloids: bahienoside A, desoxycordifoline and desoxycordifolinic acid.
Additionally, thiohydantoins and thioureas were synthesized from amino acids and R-
(+)-limonene, in order to assess the cooperative effect of indole nucleus combined with
terpene, thiourea and thiohydantoin units. Preliminary tests showed that
desoxycordifoline, hydantoin (20) and thiohydantoin necrostatin-1 (14) inhibit the
enzyme MAO-A higher than 80% at concentrations of 175 mM, 100 mM, 386 mM,
respectively. Also, the polar extracts of the leaves of Psychotria sp. showed antioxidant
activity with IC50 < 50 mg.mL-1 measured by DPPH free radical scavenging assay.
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MORAES, Aline Pereira. Alcaloides indólicos das partes aéreas de psychotria sp.(rubiaceae) e síntese de tiohidantoínas e tioureias derivadas de aminoácidos e do r-(+)-limoneno. 2013. 169 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Goiânia, 2013.