Alkaloids and biological activity of beribá (Annona hypoglauca)

ABSTRACT

ABSTRACT Annona hypoglauca Mart., Annonaceae, popularly known as “beribá”, was collected in flooded areas of the Amazonian Rain Forest. The crude extract obtained from this species was found to be cytotoxic against human cancer cells. Chemical information on A. hypoglauca is scarce. So, the present work aimed the isolation and identification of its alkaloids and to test their cytotoxic activity. Alkaloids were obtained from stem by acid–base partitioning and the remaining alkaloid-free extract was partitioned with organic solvents. Gas chromatography–mass spectrometry GC/MS analysis of total alkaloids allowed the identification of four aporphine alkaloids: actinodaphnine, anonaine, isoboldine and nornuciferine. Total alkaloids were fractionated by column chromatography and were purified by preparative thin-layer-chromatography, which allowed the isolation of two aporphine alkaloids, actinodaphnine and isoboldine, characterized by NMR and CG–MS analyses. This is the first report for the occurrence of actinodaphnine in Annona species. All the samples were tested in cytotoxic and antibacterial assays. Total alkaloid extract and its fractions showed antimicrobial activity against Staphylococcus aureus and Enterococcus faecalis. In the cytotoxicity assay, the crude extract showed a lethal effect against breast and colon cancer cells. Isoboldine-containing FA5 and actinodaphnine-containing FA6 showed activity against breast cancer cell line, while the alkaloid-free fractions did not show significant activity against cancer cell lines.