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.
Rashid
M A
MA
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.
Gustafson
K R
KR
Boswell
J L
JL
Boyd
M R
MR
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