New cyclic peptides from the Indonesian sponge Theonella swinhoei

Three new cyclic peptides, barangamides B, C, and D and a new depsipeptide, theonellapeptolide IIe as well as known theonellapeptolides Ia, Id, Ie, II d have been isolated from the sponge Theonella swinhoei collected in Barang lompo Island, Indonesia. The structures of barangamides were elucidated by interpretation of NMR data and application of Marfey's method. The structur e of theonellapeptolide IIe, a mixture of several conformers showing comple x NMR spectra, was determined by MS analysis of a ring-opened product and b y chemical reaction. Some of the theonellapeptolides showed mild immunosupp ressive activity, while barangamide A was inactive. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.