Phomactin E, F, and G: New Phomactin-group PAF Antagonists from a Marine Fungus Phoma sp

Platelet activating factor (PAF) is a naturally occurring etherphospholipid that is a mediator of anaphylaxis released by a number of stimulated cells. In the course of finding PAF antagonists from metabolites of a marine fungus Phoma sp., we have discovered novel PAF antagonists: phomactin A, B. B sub(1), B sub(2), D. Chu et al. also reported several PAF antagonists with the same skeletal framework as phomactins. Recently we found three related compounds; phomactin E (1), F (2), and G (3). In this paper, we report the structures and PAF antagonistic activities of 1, 2, and 3.