Habbemines a and b, pyrrolidine alkaloids with human δ-opioid receptor binding affinity from the leaves of Elaeocarpus habbemensis

The first phytochemical investigation of the Papua New Guinean plant Elaeocarpus habbemensis resulted in the isolation of two new pyrrolidine alkaloids, habbemines A (2) and B (3), as a 1:1 mixture of inseparable diastereomers. The structures of these compounds and their relative configurations were determined by spectroscopic means. An equimolar mixture of habbemines A and B showed human delta-opioid receptor binding affinity with an IC50 of 32.1 mu M.