The KEAP1-Nrf2/ARE pathway is a pivotal cytoprotective regulator against oxidative stress which plays an important role in the development of many inflammatory diseases and cancer. Activation of the Nrf2 transcription factor by oxidative stress or electrophiles regulates antioxidant response element (ARE)-dependent transcription of antioxidative, detoxifying, and anti-inflammatory proteins. Therefore, modulators of the KEAP1-Nrf2/ARE pathway have received considerable interest as therapeutics to protect against diseases where oxidative stress constitutes the underlying pathophysiology. In a search for fungal secondary metabolites affecting the Nrf2/ARE-dependent expression of a luciferase reporter gene in BEAS-2B cells, three new perylenequinones, compounds 1, 2, and 3, together with altertoxin-I (ATX-I), were isolated from fermentations of an Alternaria species. The structures of the compounds were elucidated by a combination of one- and two-dimensional NMR spectroscopy and mass spectrometry. Compound 1 and ATX-I exhibited strong cytotoxic effects with LC₅₀-values of 3.8 µM and 6.43 µM, respectively, whereas compound 3 showed no cytotoxic effects up to 100 µM on BEAS-2B cells. ATX-I induced ARE-dependent luciferase expression approximately fivefold and compound 1 approximately 2.6-fold at a concentration of 3 µM in transiently transfected BEAS-2B cells. In addition, compound 1 and ATX-I exhibited strong oxidative effects, whereas compound 3 did not show significant oxidative properties. For compound 1 and ATX-I, a strong upregulation of heme oxygenase-1 could be observed on mRNA and protein level in treated BEAS-2B cells. Moreover, compound 3 significantly decreased sod3 mRNA levels after induction of oxidative stress with benzoquinone.

KEAP1-Nrf2/ARE 通路是对抗氧化应激的关键细胞保护调节因子，在许多炎症性疾病和癌症的发展中发挥着重要作用。氧化应激或亲电子试剂激活 Nrf2 转录因子可调节抗氧化反应元件 (ARE) 依赖性抗氧化、解毒和抗炎蛋白的转录。因此，KEAP1-Nrf2/ARE 通路的调节剂作为预防氧化应激构成潜在病理生理学疾病的治疗剂受到了极大的关注。在寻找影响 BEAS-2B 细胞中荧光素酶报告基因 Nrf2/ARE 依赖性表达的真菌次生代谢物中，三种新的苝醌化合物 1 、 2 和 3 以及交替毒素-I ( ATX - I ) 被研究出来。从链格孢属物种的发酵中分离出来。通过一维和二维核磁共振波谱和质谱的结合阐明了化合物的结构。化合物1和ATX-I表现出强的细胞毒性作用，LC ₅₀值分别为3.8μM和6.43μM，而化合物3对BEAS-2B细胞高达100μM则没有细胞毒性作用。在瞬时转染的 BEAS-2B 细胞中，浓度为 3 µM 时，ATX-I 诱导 ARE 依赖性荧光素酶表达约五倍，化合物1约诱导 2.6 倍。此外，化合物1和ATX-I表现出强氧化作用，而化合物3没有表现出显着的氧化特性。对于化合物1和ATX-I，在处理的BEAS-2B细胞中可以在mRNA和蛋白质水平上观察到血红素加氧酶-1的强烈上调。此外，在用苯醌诱导氧化应激后，化合物3显着降低了sod3 mRNA 水平。