Barangamide A, a new cyclic peptide from the Indonesian sponge Theonella swinhoei

Barangamide A has been isolated from the sponge Theonella swinhoei, collect ed at Baranglompo Island, Indonesia, and the structure elucidated by interp retation of spectral data and application of Marfey's method. Barangamide A is a cyclic undecapeptide possessing three N-methylated amino acids, three beta-alanine and the same amino acid sequence with the ring portion of the known theonellapeptolide lid isolated also in the present work. The theone llapeptolides have been reported to have moderate cytotoxicity, whereas bar angamide A was inactive at the same concentration. (C) 1999 Elsevier Scienc e Ltd. All rights reserved.