title: Characterization of a Dispiroketal Spirolide Subclass from Alexandrium ostenfeldii.
abstract: A new subclass of spirolide marine toxins, represented by spirolides H (1) and I (2), were isolated from the marine dinoflagellate Alexandrium ostenfeldii. Spirolides H and I are structurally distinct from other spirolides in that they contain a 5:6 dispiroketal ring system rather than the trispiroketal ring system characteristic of previously isolated spirolides. The structures were assigned using a combination of spectrometric and spectroscopic techniques. Previously isolated spirolides containing a cyclic imine moiety showed toxicity in the mouse bioassay. Spirolide H contains this cyclic imine moiety but does not show toxicity in the mouse assay, suggesting that the presence of the cyclic imine moiety is not the only structural requirement for toxicity.
authors: Institute for Marine Biosciences, National Research Council of Canada, Halifax, Nova Scotia, Canada B3H 3Z1.
authors: Joy S
authors: JS
authors: Roach
authors: Patricia
authors: P
authors: Leblanc
authors: Nancy I
authors: NI
authors: Lewis
authors: Rex
authors: R
authors: Munday
authors: Michael A
authors: MA
authors: Quilliam
authors: Shawna L
authors: SL
authors: Mackinnon
mesh_terms: D000818:Animals; D004141:Dinoflagellida / Q000737:chemistry*; D008387:Marine Toxins / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity*; D051379:Mice; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013141:Spiro Compounds / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity*; D013329:Structure-Activity Relationship
chemical_list: D008387:Marine Toxins; D013141:Spiro Compounds; C543775:spirolide H; C543774:spirolide I