Hedopeptolide,a NO Production Inhibitor from theMarine Cyanobacterium <i>Okeania</i> sp.

A novel 19-membered cyclic depsipeptide, hedopeptolide (<b>1</b>), was isolated from <i>Okeania</i> sp., a marine cyanobacterium collected in Okinawa, Japan. Its gross structure was determined by spectroscopic analyses, and the absolute configuration of the chiral centers was determined by single-crystal X-ray diffraction analysis following crystallization. Hedopeptolide (<b>1</b>) inhibited the lipopolysaccharide-induced nitric oxide production in RAW264.7 cells.