title: Isolation, structure elucidation, relative LC-MS response, and in vitro toxicity of azaspiracids from the dinoflagellate Azadinium spinosum.
abstract: We identified three new azaspiracids (AZAs) with molecular weights of 715, 815, and 829 (AZA33 (3), AZA34 (4), and AZA35, respectively) in mussels, seawater, and Azadinium spinosum culture. Approximately 700 μg of 3 and 250 μg of 4 were isolated from a bulk culture of A. spinosum, and their structures determined by MS and NMR spectroscopy. These compounds differ significantly at the carboxyl end of the molecule from known AZA analogues and therefore provide valuable information on structure-activity relationships. Initial toxicological assessment was performed using an in vitro model system based on Jurkat T lymphocyte cytotoxicity, and the potencies of 3 and 4 were found to be 0.22- and 5.5-fold that of AZA1 (1), respectively. Thus, major changes in the carboxyl end of 1 resulted in significant changes in toxicity. In mussel extracts, 3 was detected at low levels, whereas 4 and AZA35 were detected only at extremely low levels or not at all. The structures of 3 and 4 are consistent with AZAs being biosynthetically assembled from the amino end.
authors.affiliation: Marine Institute , Rinville, Oranmore, Galway, Ireland.
authors.forename: Jane
authors.initials: J
authors.lastname: Kilcoyne
authors.forename: Ciara
authors.initials: C
authors.lastname: Nulty
authors.forename: Thierry
authors.initials: T
authors.lastname: Jauffrais
authors.forename: Pearse
authors.initials: P
authors.lastname: McCarron
authors.forename: Fabienne
authors.initials: F
authors.lastname: Herve
authors.forename: Barry
authors.initials: B
authors.lastname: Foley
authors.forename: Frode
authors.initials: F
authors.lastname: Rise
authors.forename: Sheila
authors.initials: S
authors.lastname: Crain
authors.forename: Alistair L
authors.initials: AL
authors.lastname: Wilkins
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Twiner
authors.forename: Philipp
authors.initials: P
authors.lastname: Hess
authors.forename: Christopher O
authors.initials: CO
authors.lastname: Miles
mesh_terms: D004141:Dinoflagellida / Q000737:chemistry*; D006801:Humans; D019169:Jurkat Cells / Q000187:drug effects*; D008387:Marine Toxins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013141:Spiro Compounds / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D000095702:Polyether Toxins
chemical_list: D008387:Marine Toxins; D013141:Spiro Compounds; C406592:azaspiracid; D000095702:Polyether Toxins