title: Wewakamide A and guineamide G, cyclic depsipeptides from the marine cyanobacteria Lyngbya semiplena and Lyngbya majuscula.
abstract: Two new cyclic depsipeptides wewakamide A (1) and guineamide G (2) have been isolated from the marine cyanobacterium Lyngbya semiplena and Lyngbya majuscula, respectively, collected from Papua New Guinea. The amino and hydroxy acid partial structures of wewakamide A and guineamide G were elucidated through extensive spectroscopic techniques, including HR-FABMS, 1D (1)H and (13)C NMR, as well as 2D COSY, HSQC, HSQCTOCSY, and HMBC spectra. The sequence of the residues of wewakamide A was determined through a combination of ESI-MS/MS, HMBC, and ROESY. Wewakamide A possesses a β-amino acid, 3-amino-2-methylbutanoic acid (Maba) residue, which has only been previously identified in two natural products, guineamide B (3) and dolastatin D (4). Although both new compounds (1,2) showed potent brine shrimp toxicity, only guineamide G displayed significant cytotoxicity to a mouse neuroblastoma cell line with LC(50) values of 2.7 micrometer.
authors.affiliation: Department of Ocean Science and Engineering, Zhejiang University, Hangzhou, China 310028. hanbingnan@zju.edu.cn
authors.forename: Bingnan
authors.initials: B
authors.lastname: Han
authors.forename: Harald
authors.initials: H
authors.lastname: Gross
authors.forename: Kerry L
authors.initials: KL
authors.lastname: McPhail
authors.forename: Doug
authors.initials: D
authors.lastname: Goeger
authors.forename: Claudia S
authors.initials: CS
authors.lastname: Maier
authors.forename: William H
authors.initials: WH
authors.lastname: Gerwick
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001156:Artemia / Q000187:drug effects; D045744:Cell Line, Tumor; D000458:Cyanobacteria / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D047630:Depsipeptides / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D051379:Mice; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010219:Papua New Guinea; D010449:Peptide Mapping; D012623:Seawater / Q000382:microbiology*
chemical_list: D047630:Depsipeptides