In 1996 Uemura and co-workers reported the isolation and
structural characterization of two novel alkaloids. Pinnaic
acid (1),1 which was isolated from the Okinawan bivalve
Pinna muricata, was found to be a specific inhibitor of
cytosolic phospholipase A2 (cPLA2) with an in vitro IC50 of
0.2 mM. cPLA2 is involved in regulating inflammation and
thus represents a potential target for drug discovery. Halichlorine
(2), which was isolated from the marine sponge
Halichondria okadai