MARINE NATURAL-PRODUCTS .33. THEONELLAPEPTOLIDE-IID, A NEW TRIDECAPEPTIDE LACTONE FROM THE OKINAWAN MARINE SPONGE THEONELLA-SWINHOEI

Following the characterization of theonellapeptolides Ia-Ie (2-6), ano ther new tridecapeptide lactone named theonellapeptolide IId (1) was i solated from the Okinawan marine sponge Theonella swinhoei. The struct ure of 1 has been determined on the bases of chemical and physicochemi cal examinations which included an HPLC-CD combined analysis of the am ino acid composition. Theonellapeptolide IId (1) prevented fertilizati on of the sea urchin Hemicentrotus pulcherrimus at the concentration o f 25 mu g/ml or greater but did not affect early embryonic development of fertilized eggs up to the gastrula stage.