Pulmonarins A and B are two new dibrominated marine acetylcholinesterase inhibitors that were isolated and characterized from the sub-Arctic ascidian Synoicum pulmonaria collected off the Norwegian coast. The structures of natural pulmonarins A and B were tentatively elucidated by spectroscopic methods and later verified by comparison with synthetically prepared material. Both pulmonarins A and B displayed reversible, noncompetitive acetylcholinesterase inhibition comparable to several known natural acetylcholinesterase inhibitiors. Pulmonarin B was the strongest inhibitor, with an inhibition constant (K-i) of 20 mu M. In addition to reversible, noncompetitive acetylcholinesterase inhibition, the compounds displayed weak antibacterial activity but no cytotoxicity or other investigated bioactivities.
This work was supported with grants from the Marine Biotechnology Programme in Tromsø (MABIT, BS0058), Norway, the Research Council of Norway (184688/S40),
MabCent-SFI, and the University of Tromsø (UiT), Tromsø, Norway. The authors would like to thank Prof. B. Gulliksen (Department of Arctic and Marine Biology, UiT, Norway) for sample collection, taxonomic identification, and organism image and Dr. J. Isaksson (Department of Chemistry, UiT, Norway) for operating the 600 MHz NMR.
- marine natural-products
- verongida sponges
- drug discovery