Tese
Colletia paradoxa (Spreng.) escalante (Rhamnaceae): identificação de flavonoides, diversidade genética e conservação
Fecha
2019-01-09Autor
Záchia, Nelci Rolim Bastos
Institución
Resumen
Colletia Comm. ex Juss. is a genus of the family Rhamnaceae, which counts five unique species of
South America, with two of them arriving until Brazil. C. paradoxa morphotype "paradoxa", C.
paradoxa morphotype "exserta", C. paradoxa morphotype "intermediate", resulting in questions
about the limits of this species. It is known that C. paradoxa occurs in small fragmented populations
and that the high degree of degradation and fragmentation of the natural environments can cause,
through the reduction of specific habitats, the isolation of the populations, reducing the gene flow
between them and consequently losing the genetic variability, which can thus initiate a process of
extinction of the species. It is a medicinal species having the roots and bark of the branches used to
lower the fever and is on the list of endangered species in RS and Brazil. The objective of this study
is to identify the flavonoids present in the crude extract of the leaves and branches of C. paradoxa
and its different morphotypes, to investigate the antimicrobial action and the antioxidant activity of
these extracts, contribute to a better knowledge of the species C. paradoxa and its taxonomic
delimitation and to estimate the genetic diversity of populations of C. paradoxa of molecular
markers, considering their condition as an endangered species. The capacity of elimination of free
radicals was determined by the DPPH method, the antimycobacterial activity by the broth
microdilution method and the phenolic content quantified by the spectrophotometric method and
by high performance liquid chromatography (HPLC). Genetic diversity was estimated through
ISSR markers and species delimitation was performed through morphological analysis associated
with ISSR markers. It was concluded that C. paradoxa has a natural antioxidant potential, in
addition to presenting an antimycobacterial activity classified as moderate to significant. The
similarity in the phytochemical results of the individuals of the three morphotypes, the
morphological analysis and the ISSR corroborate with the idea that they are a single species, C.
paradoxa, however, it is encouraged the continuity of the researches in order to deepen the
knowledge about the biology, potentialities and preservation of the species. With respect to the
genetic diversity of the species, it is concluded that it presents moderate diversity, which added to
the environmental risks identified in the natural populations reinforces that the species is threatened
with extinction in the state of Rio Grande do Sul.