Metabólitos secundários obtidos através do estudo das raízes de Psychotria prunifolia (Kunth) Steyerm (Rubiaceae), transformações e ensaios biológicos de seu extrato
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2010-08-31
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Universidade Federal de Goiás
Resumo
Psychotria prunifolia is an endemic shrub from the Goias cerrado that belongs
to the Rubiaceae family and to the Psychotrieae tribe. Extracts and fractions
from Psychotria genera species are known for its cytotoxic potentials, and a wide
range of studies have reported anticancer activity as well as the presence of nonmonoterpenic
indole alkaloids and iridoids. Alkaloids are also used as chemotaxonomic
indicators by means of classification of the species from such genera and the
Psychotria and Heteropsychotria subgenera.
This study focuses on the phytochemical assay of the P. prunifolia roots, the
chemical transformations of two of the metabolites obtained, and the evaluation of
antioxidant and molluscicidal crude roots, stems and leaves extracts activity. Column
chromatography fractioning of crude roots extract and submission to successive
layer preparative chromatography led to the isolation of five compounds: sitosterol
(LCPP-1), a benzidenone derivative (LCPP-2) not yet described for this family, and
three β-carboline alkaloids (LCPP-3, LCPP-4 and LCPP-5). Alkaloid LCPP-4 is unpublished
and the others have already been isolated from the leaves of this species.
The acid-base fractionation allowed the isolation of strictosamide (LCPP-6), a well
known alkaloid isolated from the leaves of this species and other species of this genus.
Chemical transformation of the alkaloid LCPP-3 to LCPP-4 have been observed
through their 1H, 13C, HSQC, and HMBC NMR-spectra. Some suggestions for
these transformations were proposed.
Crude extract from roots, branches and leaves were evaluated using the
DPPH radical scavenging method, and a 50% loss in absorbance was observed in
145, 162.4, and 231.6 ppm concentrations, respectively. The molluscicidal assay
with the crude roots extract of showed no activity.
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RIBEIRO, Laryssa Campos. Secondary metabolites obtained by studying the roots of Psychotria prunifolia (Kunth) Steyerm (Rubiaceae), transformations and biological tests of its extract. 2010. 170 f. Dissertação (Mestrado em Educação em Química) - Universidade Federal de Goiás, Goiânia, 2010.