Tallini_2017_Molecules_22_

The Amaryllidaceae family has proven to be a rich source of active compounds, which are characterized by unique skeleton arrangements and a broad spectrum of biological activities. The aim of this work was to perform the first detailed study of the alkaloid constituents of Hippeastrum reticulatum (Amaryllidaceae) and to determine the anti-parasitological and cholinesterase (AChE and BuChE) inhibitory activities of the epimers (6alpha-hydroxymaritidine and 6beta-hydroxymaritidine). Twelve alkaloids were identified in H. reticulatum: eight known alkaloids by GC-MS and four unknown (6alpha-hydroxymaritidine, 6beta-hydroxymaritidine, reticulinine and isoreticulinine) by NMR. The epimer mixture (6alpha-hydroxymaritidine and 6beta-hydroxymaritidine) showed low activity against all protozoan parasites tested and weak AChE-inhibitory activity. Finally, a molecular docking analysis of AChE and BuChE proteins showed that isoreticulinine may be classified as a potential inhibitory molecule since it can be stabilized in the active site through hydrogen bonds, pi-pi stacking and hydrophobic interactions.