Colletia paradoxa (Spreng.) escalante (Rhamnaceae): identificação de flavonoides, diversidade genética e conservação

Abstract

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.