Grandisine A and B, Novel Indolizidine Alkaloids with Human δ-Opioid Receptor Binding Affinity from the Leaves of the Australian Rainforest Tree Elaeocarpus grandis

Abstract

Two novel indolizidine alkaloids, grandisine A (1) and B (2), and the known alkaloid (-) isoelaecarpiline (3) were isolated from the leaves of Elaeocarpus grandis and their structures determined by 1D and 2D NMR spectroscopy. The compounds showed affinity for the human d-opioid receptor. Grandisine A contains a unique tetracyclic skeleton, whilegrandisine B possesses the unique combination of isoquinuclidinone and indolizidine groups in one molecule.