Isolamento e caracterização de alcaloides aporfinoides de frações enriquecidas da fase alcaloídica obtida por tratamento ácido-base do extrato metanólico das cascas de Duguetia surinamensis R. E. Fries (Annonaceae)

Abstract

The genus Duguetia (Annonaceae) is recognized for producing specialized metabolites, particularly aporphinoid alkaloids, which are associated with a wide range of biological activities and are of considerable interest in Natural Products Chemistry. In this context, the present study aimed to investigate enriched fractions of the alkaloid phase obtained through acid-base treatment of the methanolic bark extract of Duguetia surinamensis R. E. Fries, with the purpose of isolating, purifying, and structurally characterizing their chemical constituents. The selected fractions were subjected to successive fractionation by preparative thin-layer chromatography (PTLC), and the isolated compounds were characterized by Nuclear Magnetic Resonance spectroscopy (1H and 13C NMR) and Mass Spectrometry (MS). The analyses led to the identification of the aporphinoid alkaloids 11-methoxyduguesuramine, dicentrinone, and duguetine N-oxide, as well as the phenolic compound methyl syringate. Methyl syringate is reported for the first time in the investigated species. These results expand the phytochemical knowledge of the chemical composition of Duguetia surinamensis, demonstrating the occurrence of aporphine alkaloids as well as phenolic compounds in alkaloid-enriched fractions, and providing support for future chemical and pharmacological investigations.