title: Leucamide A: a new cytotoxic heptapeptide from the Australian sponge Leucetta microraphis.
abstract: Leucamide A (1), a bioactive cyclic heptapeptide containing a unique mixed 4,2-bisheterocycle tandem pair consisting of a methyloxazole and thiazole subunit was isolated together with the known compound BRS1 (2), from the dichloromethane extract of the Australian marine sponge Leucetta microraphis. The planar structure of leucamide A (1) was elucidated by employing spectroscopic techniques (NMR, MS, UV, and IR). Its absolute stereochemistry was established by chemical degradation, derivatization, and chiral GC[bond]MS analysis. A conformational analysis of 1 was made using MMFF. Leucamide A (1) was found to be moderately cytotoxic toward several tumor cell lines.
authors.affiliation: Institute for Pharmaceutical Biology, University of Bonn, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kehraus
authors.forename: Gabriele M
authors.initials: GM
authors.lastname: König
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Wright
authors.forename: Gert
authors.initials: G
authors.lastname: Woerheide
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D000605:Amino Alcohols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001315:Australia; D002478:Cells, Cultured / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004354:Drug Screening Assays, Antitumor; D005233:Fatty Alcohols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008113:Liver Neoplasms; D008958:Models, Molecular; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D011161:Porifera / Q000737:chemistry*; D013237:Stereoisomerism; D013274:Stomach Neoplasms
chemical_list: D000596:Amino Acids; D000605:Amino Alcohols; D000970:Antineoplastic Agents; C108399:BRS1 compound; D005233:Fatty Alcohols; D010456:Peptides, Cyclic; C470214:leucamide A