Investigação fitoquímica de espécies do gênero Erythroxylum

• Ano de defesa: 2023
• Autor(a) principal: Dantas, César Augusto Gonçalves
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraíba; Brasil; Farmacologia; Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos; UFPB
• Palavras-chave em Português: Erythroxylaceae; Alcaloides tropânicos; Compostos fenólicos; Espectroscopia; Cromatografia; Tropane alkaloids; Phenolic compounds; Spectroscopy; Chromatography; CNPQ::CIENCIAS BIOLOGICAS::FARMACOLOGIA
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/123456789/29344

Several secondary metabolites of different classes can be evidenced in species of the genus Erythroxylum, with emphasis on flavonoids, terpenes and tropane alkaloids, the latter being considered markers of the genus. Because many of these compounds are already described in the scientific literature, modern screening and identification methodologies, such as dereplication, are necessary to direct the isolation of the metabolites of interest, representing an efficient, fast and safe strategy. This work aimed to trace the chemical profile of the secondary metabolites present in the chloroform, ethyl acetate and n-butanolic phases of the aerial parts of the species Erythroxylum simonis Plowman, Erythroxylum pauferrense Plowman, Erythroxylum pulchrum St. Hil. and Erythroxylum revolutum Mart. by dereplication methodologies. For this purpose, the phases were analyzed by high-performance liquid chromatography coupled to mass spectrometry with electrospray ionization, then the experiments were repeated with the chromatograph coupled to a high-resolution mass spectrometer, also with an electrospray ionization source, ethyl acetate and nbutanolic phases were analyzed in negative mode and chloroform phases in positive mode. The annotation of the compounds was carried out based on the ions of their deprotonated or protonated molecules, molecular formulas, fragmentation patterns and by comparing the data obtained with those present in the scientific literature. Compounds not fully annotated were isolated and characterized by 1H and 13C NMR spectroscopy. Through the analyzes carried out, it was possible to trace and compare the chemical profile of the secondary metabolites of the Erythroxylum species. The dereplication of the ethyl acetate and n-butanolic phases led to the annotation of 55 phenolic compounds, highlighting glycosylated flavonoids, phenolic acids, procyanidins, flavolignans and lignoids, most being described for the first time in the studied species, and some unpublished for the genus Erythroxylum and for the family Erythroxylaceae. The dereplication of the chloroform phases led to the annotation of 29 tropane alkaloids, some also being described for the first time in the genus and family of the studied species. From the ethyl acetate phase of E. simonis, the isolation of cinchonaines Ia and Ib, epicatechin, quercetin-O-hexoside, and biphenyl-3,3',4,4'- tetraol, described for the first time in the species, was isolated. Three compounds were isolated from the chloroform phase of E. revolutum, the protonated 6-(benzoyloxy)-3- (3,5-dimethoxy-4-hydroxybenzoyloxy)tropane, protonated 6-(benzoyloxy)-3-(3,4,5- trimethoxybenzoyloxy)tropane and protonated 6-(benzoyloxy)-3-(3,4,5- trimethoxycinnamoyloxy)tropane, reported for the first time in the species E. revolutum. This work contributed to the phytochemical knowledge of the genus Erythroxylum and demonstrates the efficiency and importance of using methodologies for guided isolation of secondary metabolites in research on natural products.