ISOLAMENTO E CARACTERIZAÇÃO ESTRUTURAL DE ALCALOIDES EM OCOTEA DIOSPYRIFOLIA (LAURACEAE)

Abstract

Natural products are recognized as valuable sources of bioactive molecules with therapeutic potential and are widely used as starting points for the development of new drugs and phytotherapeutics. Among these, alkaloids stand out for their structural diversity and broad spectrum of pharmacological activities, making them important targets in the bioprospecting of plant species. The Lauraceae family, widely distributed in tropical and subtropical regions, is notable for its richness in secondary metabolites such as terpenes, polyphenols, phenylpropanoids, and especially alkaloids. Within this family, the genus Ocotea is particularly relevant, with Ocotea diospyrifolia (Meisn.) Mez being a native South American species traditionally used for treating colds, inflammation, and other ailments. Although preliminary studies have reported antioxidant, antimicrobial, acaricidal, cytotoxic, and anti-inflammatory activities in extracts and essential oils of this species, its bioactive compounds remain largely uncharacterized at the molecular level. This study aimed to isolate, purify, and structurally characterize alkaloids from the alkaloid-rich fraction of O. diospyrifolia, thereby contributing to the phytochemical knowledge of the species and identifying potential bioactive compounds. Plant material was collected in the Cerrado and Pantanal biomes, dried, ground, and extracted with 70% ethanol. The alkaloid fraction was obtained through acid-base partitioning and purified by semi-preparative high-performance liquid chromatography (HPLC-DAD). Isolated compounds were analyzed by high-resolution mass spectrometry (UHPLC-HRMS) and nuclear magnetic resonance (1D and 2D NMR). A total of 37 fractions were obtained, and four alkaloids were identified: reticuline, boldine, isoboldine, and laurotetanine, the latter being confirmed through long-range correlations in HMBC spectra. The crude alkaloid extract also showed signals compatible with other aporphine- and isocorydine-type alkaloids. Furthermore, previous biological assays revealed approximately 40% anti-leukemic activity against the KG-1 cell line, indicating a relevant cytotoxic potential. These results highlight O. diospyrifolia as a promising source of alkaloids with pharmacological relevance, especially for developing new bioactive prototypes targeting neoplastic diseases. This study also reinforces the value of Brazilian biodiversity and ethnopharmacological knowledge through integrated phytochemical and bioactivity research.