Ulongamides A-F, new beta-amino acid-containing cyclodepsipeptides from Palauan collections of the marine cyanobacterium Lyngbya sp.
Six new beta-amino acid-containing cyclic depsipeptides, termed ulongamides A-F (1-6), have been isolated from collections of apratoxin-producing cyanobacteria from Palau. Their planar structures have been determined by NMR spectroscopic techniques. The absolute stereochemistry of the hydroxy acid and all the alpha-amino acid-derived units was ascertained to be S by chiral HPLC analysis of degradation products. The stereochemistry of the beta-amino acid moiety, 3-amino-2-methylhexanoic acid, was established by advanced Marfey analysis of the acid hydrolyzates and found to be 2R,3R in compounds 1-3 but 2S,3R in compounds 4-6. All compounds except 6, which lacks an aromatic amino acid moiety, were weakly cytotoxic against KB cells.
Luesch
Hendrik
H
Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA.
Williams
Philip G
PG
Yoshida
Wesley Y
WY
Moore
Richard E
RE
Paul
Valerie J
VJ
D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D006868:Hydrolysis; D007624:KB Cells / Q000187:drug effects; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D019029:Palau; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured / Q000187:drug effects
D000970:Antineoplastic Agents; D010456:Peptides, Cyclic