title: Tasipeptins A and B: new cytotoxic depsipeptides from the marine cyanobacterium Symploca sp.
abstract: Two new depsipeptides have been isolated from a Symploca sp. collected in Palau. The gross structures of tasipeptins A (1) and B (2) were determined by standard spectroscopic techniques, and the absolute configuration of the amino acid units was determined by chiral HPLC. The relative stereochemistry of the 3-amino-6-hydroxy-2-piperidone (Ahp) moiety in both structures was determined by analysis of (2,3)J(H,H) values. Oxidation with PCC and acid hydrolysis unmasked this latent glutamic acid moiety, allowing for elucidation of the total configuration of 1 and 2. Tasipeptins A (1) and B (2) were cytotoxic toward KB cells with IC(50) values of 0.93 and 0.82 microM, respectively.
authors.affiliation: Department of Chemistry, University of Hawaii at Manoa, Honolulu 96822, USA.
authors.forename: Philip G
authors.initials: PG
authors.lastname: Williams
authors.forename: Wesley Y
authors.initials: WY
authors.lastname: Yoshida
authors.forename: Richard E
authors.initials: RE
authors.lastname: Moore
authors.forename: Valerie J
authors.initials: VJ
authors.lastname: Paul
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry*; D047630:Depsipeptides; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D007624:KB Cells / Q000187:drug effects; D015394:Molecular Structure; D019029:Palau; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D047630:Depsipeptides; D010456:Peptides, Cyclic; C477984:tasipeptin A; C477985:tasipeptin B