Hoplonemertine worms -- a new source of pyridine neurotoxins.

Two pyridine bases were isolated from the marine hoplonemertine Amphiporus angulatus (Fabricius) and identified by mass and PMR-spectroscopy as 2, 3'-bipyridyl and 3, 2'; 3', 2"; 4", 3"'-tetrapyridyl (Nemertelline). Nemertelline, the first tetrapyridyl natural product to be reported, shows a structural resemblance to the tobacco constituent nicotelline. The crustacean toxicity of 2, 3' -bipyridyl is very similar to that of nicotine, but its mammalian toxicity is negligible.