Antineoplastic agents 390. Isolation and structure of phakellistatin 12 from a chuuk archipelago marine sponge

A new cancer cell growth inhibitory (P388 lymphocytic leukemia ED50 2.8 mug/mL) cyclodecapeptide designated phakellistatin 12 (2) has been isolated as a trace (1.7 x 10(-6)%, yield) constituent of the Western Pacific Ocean (Federated States of Micronesia-Chuuk) sponge Phakellia sp. Employing principally a combination of high resolution FAB with high field (500 MHz) H-1, C-13 and 2-D NMR and chiral GC analyses the structure (all S chirality) cyclo-Ile-Phe-Thr-Leu-Pro-Pro-Tyr-Ile-Pro-Pro was assigned. (C) 2003 Elsevier Science Ltd. All rights reserved.