Absolute Structure Determination and Kv1.5 Ion Channel Inhibition Activities of New Debromoaplysiatoxin Analogues

Potassium channel Kv1.5 has been considered a key target for new treatments of atrial tachyarrhythmias, with few side effects. Four new debromoaplysiatoxin analogues with a 6/6/12 fused ring system were isolated from marine cyanobacterium <i>Lyngbya</i> sp. Their planar structures were e...

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Autores principales: Sicheng Shen, Weiping Wang, Zijun Chen, Huihui Zhang, Yuchun Yang, Xiaoliang Wang, Peng Fu, Bingnan Han
Formato: article
Lenguaje:EN
Publicado: MDPI AG 2021
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Acceso en línea:https://doaj.org/article/7c31b6140be4450a9a86d853edfdb956
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Sumario:Potassium channel Kv1.5 has been considered a key target for new treatments of atrial tachyarrhythmias, with few side effects. Four new debromoaplysiatoxin analogues with a 6/6/12 fused ring system were isolated from marine cyanobacterium <i>Lyngbya</i> sp. Their planar structures were elucidated by HRESIMS, 1D and 2D NMR. The absolute configuration of oscillatoxin J (<b>1</b>) was determined by single-crystal X-ray diffraction, and the absolute configurations of oscillatoxin K (<b>2</b>), oscillatoxin L (<b>3</b>) and oscillatoxin M (<b>4</b>) were confirmed on the basis of GIAO NMR shift calculation followed by DP4 analysis. The current study confirmed the absolute configuration of the pivotal chiral positions (7S, 9S, 10S, 11R, 12S, 15S, 29R and 30R) at traditional ATXs with 6/12/6 tricyclic ring system. Compound <b>1</b>, <b>2</b> and <b>4</b> exhibited blocking activities against Kv1.5 with IC<sub>50</sub> values of 2.61 ± 0.91 µM, 3.86 ± 1.03 µM and 3.79 ± 1.01 µM, respectively. However, compound <b>3</b> exhibited a minimum effect on Kv1.5 at 10 µM. Furthermore, all of these new debromoaplysiatoxin analogs displayed no apparent activity in a brine shrimp toxicity assay.