Habbemines A and B, pyrrolidine alkaloids with human delta-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 microM.

Indolizidine alkaloids with delta-opioid receptor binding affinity from the leaves of Elaeocarpus fuscoides.

In the first chemical investigation of the Papua New Guinean plant Elaeocarpus fuscoides, one new indolizidine alkaloid, elaeocarpenine (1), and three known alkaloids, isoelaeocarpicine (2), isoelaeocarpine (3), and elaeocarpine (4), were isolated from the leaves. Their structures were determined by 1D and 2D NMR spectroscopy. Since treatment of elaeocarpenine (1) with ammonia produced a 1:1 mixture of the diastereomers 3 and 4, we propose that elaeocarpenine (1) is the biogenetic precursor of isoelaeocarpine (3) and elaeocarpine (4). Compounds 1-4 demonstrated binding affinity for the human delta-opioid receptor with IC50 values of 2.7, 35.1, 13.6, and 86.4 microM, respectively.

Alkaloids with human delta-opioid receptor binding affinity from the Australian rainforest tree Peripentadenia mearsii.

Three new pyrrolidine alkaloids, peripentonine A-C ( 2- 4), one known pyrrolidine alkaloid, peripentadenine ( 1), and one novel indolizidine alkaloid, mearsamine ( 5), were isolated from the leaves of Peripentadenia mearsii and their structures determined by 1D and 2D NMR spectroscopy. Peripentonines A ( 2) and B ( 3) were isolated as a 1:1 mixture of inseparable diastereomers. Mearsamine ( 5) contains a novel tricyclic ring system. Peripentadenine and peripentonines A/B and C showed receptor binding affinity for the human delta-opioid receptor with IC 50 values of 11.4, 69.2, and 30.9 microM, respectively. Mearsamine did not bind to the delta-opioid receptor.

Grandisines C-G, indolizidine alkaloids from the Australian rainforest tree Elaeocarpus grandis.

Five new indolizidine alkaloids, grandisines C, D, E, F, and G (4-8), and one known indolizidine alkaloid, (-)-isoelaeocarpiline (3), were isolated from the leaves of Elaeocarpus grandis and their structures determined by 1D and 2D NMR spectroscopy. Grandisine C (4) is isomeric with the known compound rudrakine (1). The absolute configuration of grandisine D (5) was deduced by its conversion to (-)-isoelaeocarpiline. Grandisine E (6) contains a novel tetracyclic ring system. Grandisine F (7) is the 14-amino analogue of grandisine C. Grandisine G (8) contains the novel combination of a piperidine attached to an indolizidine. Grandisines C, D, F, and G and (-)-isoelaeocarpiline showed receptor binding affinity for the human delta-opioid receptor with IC(50) values of 14.6, 1.65, 1.55, 75.4, and 9.9 microM, respectively.