The cyanotoxins released into waters during cyanobacterial blooms can pose serious hazards to humans and animals. Apart from their toxicological mechanisms, cyanotoxins have been shown to be involved in estrogenic activity by in vivo and in vitro assays; however, there is limited information on the change in estrogenicity of cyanotoxins following chemical oxidation. In this study, the estrogenic activity of cylindrospermopsin (CYL) and anatoxin-a (ANA) at concentrations ranging from 2.4 × 10⁻⁷ M to 2.4 × 10⁻¹² M (CYL) and 7.1 × 10⁻⁶ M to 7.1 × 10⁻¹¹ M (ANA), and after treatment by the Fe^III-B*/H₂O₂ catalyst system, was investigated by the yeast estrogen screen (YES) assay. The results indicate that CYL and ANA acted as agonists in the YES assay (CYL logEC₅₀ = -8.901; ANA logEC₅₀ = -6.789), their binding affinity to estrogen receptors is associated with their intrinsic properties, including ring structures and toxicant properties. CYL and ANA were shown to simulate endocrine disrupting chemicals (EDCs) to modulate the 17β-estradiol-induced estrogenic activity, resulting in non-monotonic dose responses. The treated CYL showed a significantly altered estrogenicity compared to the untreated CYL (T₍₂₎ = 8.168, p ≤ .05), while the estrogenicity of the treated ANA was not significantly different to the untreated ANA (T₍₂₎ = 1.295, p > .05). Intermediate products generated from CYL and ANA oxidized by Fe^III-B*/H₂O₂ were identified using Q-Exactive Tandem Mass Spectrometry (LC-MS/MS). Treatment with Fe^III-B*/H₂O₂ yielded open-ring by-products which likely resulted in CYL's reduced binding affinity to estrogen receptors. The insignificant change in the estrogenicity of treated ANA was possibly a result of its multiple ring structure products, which were likely able to bind to estrogen receptors. The comparisons for the estrogenicity of these cyanotoxins before and after Fe^III-B*/H₂O₂ treatment suggest that the reductions in estrogenicity achieved by oxidation were dependent on the levels of cyanotoxins removed, as well as the estrogenicity of the degradation products. This is the first study on the change in the estrogenicity of CYL and ANA upon oxidation by Fe^III-B*/H₂O₂, a high activity catalyst system.

蓝藻水华期间释放到水中的蓝藻毒素会对人类和动物造成严重危害。除了其毒理学机制外，体内和体外试验还表明，氰毒素与雌激素活性有关。然而，关于化学氧化后氰毒素的雌激素变化的信息很少。在这项研究中，cylindrosperpsoppsin（CYL）和anatoxin-a（ANA）在2.4×10 ^-7  M至2.4×10 ^-12  M（CYL）和7.1×10 ^-6  M至7.1×10范围内的雌激素活性^-11  M（ANA），并经Fe ^III -B * / H ₂ O _2处理通过酵母雌激素筛选（YES）试验研究了催化剂体系。结果表明CYL和ANA在YES分析中起激动剂作用（CYL logEC ₅₀  = -8.901; ANA logEC ₅₀  = -6.789），它们与雌激素受体的结合亲和力与其内在性质有关，包括环结构和毒性性质。已显示CYL和ANA模拟内分泌干扰化学物质（EDC），以调节17β-雌二醇诱导的雌激素活性，从而导致非单调剂量反应。与未处理的CYL相比，已处理的CYL的雌激素性显着改变（T _（2）  = 8.168，p≤.05），而与未处理的ANA相比，经处理的ANA的雌激素性无显着差异（T _（2）） = 1.295，p> .05）。使用Q-Exactive串联质谱（LC-MS / MS）鉴定了被Fe ^III -B * / H ₂ O ₂氧化的由CYL和ANA生成的中间产物。用Fe ^III -B * / H ₂ O _2处理产生开环副产物，这可能导致CYL与雌激素受体的结合亲和力降低。经处理的ANA的雌激素性的微不足道的变化可能是由于其多个环结构产物的结果，该产物可能能够与雌激素受体结合。这些氰毒素在Fe ^III -B * / H ₂ O ₂之前和之后的雌激素性比较处理表明，通过氧化获得的雌激素性降低取决于所去除的氰毒素的水平以及降解产物的雌激素性。这是对高活性催化剂体系Fe ^III -B * / H ₂ O ₂氧化后CYL和ANA雌激素性变化的首次研究。