Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States.
Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung (AWI), Am Handelshafen 12, 27570 Bremerhaven, Germany.
J Nat Prod. 2021 Sep 24;84(9):2554-2567. doi: 10.1021/acs.jnatprod.1c00586. Epub 2021 Sep 14.
Goniodomin A (GDA, ) is a phycotoxin produced by at least four species of dinoflagellates that are found globally in brackish estuaries and lagoons. It is a linear polyketide with six oxygen heterocyclic rings that is cyclized into a macrocyclic structure via lactone formation. Two of the oxygen heterocycles in comprise a spiro-bis-pyran, whereas goniodomin B (GDB) contains a 2,7-dioxabicyclo[3.3.1]nonane ring system fused to a pyran. When HO is present, undergoes facile conversion to isomer GDB and to an α,β-unsaturated ketone, goniodomin C (GDC, ). GDB and GDC can be formed from GDA by cleavage of the spiro-bis-pyran ring system. GDA, but not GDB or GDC, forms a crown ether-type complex with K. Equilibration of GDA with GDB and GDC is observed in the presence of H and of Na, but the equilibrated mixtures revert to GDA upon addition of K. Structural differences have been found between the K and Na complexes. The association of GDA with K is strong, while that with Na is weak. The K complex has a compact, well-defined structure, whereas Na complexes are an ill-defined mixture of species. Analyses of in vitro and cultures indicate that only GDA is present in the cells; GDB and GDC appear to be postharvest transformation products.
冈田酸 A（GDA）是一种由至少四个种属的甲藻产生的藻毒素，这些甲藻在全球的半咸水河口和泻湖中均有发现。它是一个由六个含氧杂环组成的线性聚酮化合物，通过内酯形成环化成大环结构。两个含氧杂环组成一个螺环双吡喃，而冈田酸 B（GDB）则包含一个 2,7-二氧杂双环[3.3.1]壬烷环系统与吡喃融合。当存在 HO 时，GDA 容易转化为异构体 GDB 和α,β-不饱和酮，冈田酸 C（GDC）。GDB 和 GDC 可通过螺环双吡喃环系统的裂解从 GDA 形成。GDA，但不是 GDB 或 GDC，与 K 形成冠醚型配合物。在 H 和 Na 的存在下，观察到 GDA 与 GDB 和 GDC 的平衡，但加入 K 后，平衡混合物会返回到 GDA。已经发现 K 和 Na 配合物之间存在结构差异。GDA 与 K 的结合很强，而与 Na 的结合很弱。K 配合物具有紧凑、明确的结构，而 Na 配合物则是物种的不明确混合物。体外培养和的分析表明，只有 GDA 存在于细胞中；GDB 和 GDC 似乎是收获后的转化产物。
