Aerucyclamide A (ACA) is an emerging cyanopeptide toxin produced by cyanobacteria, and its transformation pathway has rarely been reported. In the present study, ACA was purified from cyanobacterial extracts, and photodegradation processes were investigated in dissolved organic matter (DOM) solutions. Under simulated solar irradiation, the photodegradation of ACA was dominated by ^•OH oxidation, accounting for ~72% of the indirect photodegradation. The bimolecular reaction rate constant of ACA with ^•OH was (6.4 ± 0.2) × 10⁹ M ^− 1 s ^− 1. Our results indicated that the major reactive sites of ACA toward ^•OH are thiazoline and thiazole moieties. Product analysis via high-resolution mass spectrometry suggested that hydrogen abstraction and gradual hydroxylation are the main photodegradation pathways. The acute toxicity assessment indicate that the products generated in photolysis process did not show any measurable toxicity to Thamnocephalus platyurus. Photodegradation experiments with various DOM-phycocyanin mixtures demonstrated that the half-life of ACA is much longer than that of microcystin-LR.

Aerucyclamide A (ACA) 是一种由蓝藻产生的新兴蓝肽毒素，其转化途径鲜有报道。在本研究中，从蓝藻提取物中纯化 ACA，并研究了溶解有机物 (DOM) 溶液中的光降解过程。在模拟太阳辐照下，ACA 的光降解主要是^• OH 氧化，约占间接光降解的 72%。ACA 与^• OH的双分子反应速率常数为 (6.4 ± 0.2) × 10 ⁹ M  ^{-  1} s  ^{-  1}。我们的研究结果表明，向ACA的主要活性位点^•OH 是噻唑啉和噻唑部分。通过高分辨率质谱的产物分析表明，夺氢和逐渐羟基化是主要的光降解途径。急性毒性评估表明光解过程中产生的产物对Thamnocephalus platyurus没有显示出任何可测量的毒性。各种 DOM-藻蓝蛋白混合物的光降解实验表明，ACA 的半衰期比微囊藻毒素-LR 长得多。