Haligramides A and B, two new cytotoxic hexapeptides from the marine sponge Haliclona nigra.
Bioassay-guided fractionation of a cytotoxic aqueous extract of the sponge Haliclona nigra provided two new cyclic hexapeptides, haligramides A (1) and B (2), in addition to the known peptide, waiakeamide (3). The structures of peptides 1 and 2 were elucidated by extensive NMR analyses and by comparison of their spectral data with those of waiakeamide (3). The identity of haligramide A (1) was confirmed by its oxidative conversion to waiakeamide (3). Further structural confirmation was provided by oxidation of peptides 1, 2, and 3 to the common bis-sulfone derivative 4.
Laboratory of Drug Discovery Research and Development, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Frederick Cancer Research and Development Center, Frederick, MD 21702-1201, USA.
M A
MA
Rashid
K R
KR
Gustafson
J L
JL
Boswell
M R
MR
Boyd
D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D011161:Porifera / Q000737:chemistry*; D013057:Spectrum Analysis; D013844:Thiazoles / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
D000970:Antineoplastic Agents; D010456:Peptides, Cyclic; D013844:Thiazoles; C413032:haligramide A; C413033:haligramide B