Isolamento de alcaloides de frações enriquecidas da fase diclorometano básica do extrato metanólico das cascas de Duguetia surinamensis (Annonaceae)

Abstract

Duguetia surinamensis R. E. Fries is a species of the Annonaceae family distributed mainly in the Amazon basin, occurring in countries such as Colombia, Guyana, Suriname, Peru, and French Guiana, and in Brazil, especially in the states of Acre, Amapá, Rondônia, Pará, and Amazonas. It is popularly known by names such as "envira," "envireira," "araticum," and "biribarana. The genus (Duguetia), as well as its family, is characterized by a broad diversity of specialized metabolites, especially isoquinoline alkaloids, which display relevant pharmacological activities.. Previous studies with D. surinamensis identified novel alkaloids and evidenced relevant cytotoxic activities. However, only a fraction of the species of the genus Duguetia have been chemically and pharmacologically investigated. Thus, the present work aimed to continue the investigations with D. surinamensis, with emphasis on the analysis of the basic dichloromethane fraction of the methanolic extract of the stem bark. Using classical chromatographic techniques: column chromatography (CC), analytical thinlayer chromatography (ATC), and preparative thin-layer chromatography (PTLC), it was possible to isolate and identify two aporphine alkaloids, namely (DSC-6.3) and (DSC-6.4, DSC-11.3, DSC-11.4). Structural identification of the compounds was performed based on 1H and 13C nuclear magnetic resonance (1H and 13C NMR) analyses, resulting in the identification of the following compounds: dicentrinone (DSC6.3) and duguetine N-oxide (DSC-6.4, DSC-11.3, DSC-11.4).