Prospecção química e biológica de espécies coletadas na caatinga: Euphorbia tirucalli Linneau, Bredemeyera floribunda Willd. e Bredemeyera brevifolia Benth
The Caatinga biome constitutes an important potential of vegetal formation, with numerous species reported in the literature for the broad spectrum of biological activities and chemical diversity presented. Due chemistry and biological potential of this biome, the present study approaches the phy...
Na minha lista:
| Autor principal: | |
|---|---|
| Outros Autores: | |
| Formato: | doctoralThesis |
| Idioma: | pt_BR |
| Publicado em: |
Universidade Federal do Rio Grande do Norte
|
| Assuntos: | |
| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/33208 |
| Tags: |
Adicionar Tag
Sem tags, seja o primeiro a adicionar uma tag!
|
| Resumo: | The Caatinga biome constitutes an important potential of vegetal formation, with
numerous species reported in the literature for the broad spectrum of biological
activities and chemical diversity presented. Due chemistry and biological potential of
this biome, the present study approaches the phytochemical investigation of three plant
species collected in the northeastern caatinga: Euphorbia tirucalli Linn., Bredemeyera
floribunda Willd. and Bredemeyera brevifolia Benth. The LC-MS analysis, in negative
mode, applied to the extracts of the three species allowed the evaluation of the
phytochemical profile of the species and thus found the flavonoids as the predominant
class of metabolites. The chemical study of the hexane and ethanolic extracts from
aerial parts and roots of E. tirucalli, respectively, using chromatographic techniques,
allowed the isolation of five constituents: two already isolated in the species, β-amyrin
and 4-O-methyl-gallic acid, and three unpublished compounds in the species,
ampelopsin, myricetin and 3,3'-dimethoxyellagic acid-4-O-α-rhamnopyranoside. The
evaluation of the antioxidant activity from E. tirucalli extracts against DPPH and ABTS
showed the potential of the ethanolic root extract against both radicals, whereas among
the compounds isolated myricetin showed the best inhibition of radicals with IC50 of
22.62 μg/mL for DPPH and 53.22 μg/mL for ABTS. The evaluation of antimicrobial
activities showed antibacterial and antifungal potential of the ethanolic extracts, while
all the isolated compounds showed inhibitory effect against strains of S. aureus, E. coli,
S.brasiliensis and C. Albicans, with greater effect for myricetin and ampelopsin. The
study of species of the genus Bredemeyera was also promising. Chromatographic
treatments applied to the hydroalcoholic extract of B. floribunda roots allowed the
isolation of two compounds, methyl (2E)-3'-(3,4,5-trimethoxyphenyl)-prop-2-enoate
and 1,7- dihydroxy-3,4,8-trimethoxixantone both already isolated in the species, while
the chromatographic procedure applied to the ethanolic extract of the stems led to the
isolation of three flavonoids, rutin, canferol and quercetin being the last two isolates for
the first time in the species. The study of the hydroalcoholic extract from B. brevifolia
roots allowed the identification and isolation of two flavones, 5,7,4'-trihydroxy-3'-
methoxyflavone and 5,7,2',3',4'-pentahydroxy-6, 4'-dimethoxyflavone. The evaluation
of the in vitro enzymatic activity against Bothrops jararaca venom showed relevant
results, since it was verified that B. jararaca venom was totally inhibited by the
hydroalcoholic extract of B. brevifolia roots, proving to be a very interesting data
because the relevance of this class of toxins in snake poisoning. This study contributed
to the chemical and biological knowledge of the three species studied, with new isolated
molecules for each species, as well as unpublished biological data associated with
Bredemeyera antiofidic activity and Euphorbia tirucalli antimicrobial activity. |
|---|