A study targeting novel antifungal metabolites identified potent in vitro antifungal activity against key plant pathogens in acetone extracts of Streptomyces sp. strain CA-296093. Feature-based molecular networking revealed the presence in this extract of antimycin-related compounds, leading to the isolation of four new compounds: escuzarmycins A–D (1–4). Extensive structural elucidation, employing 1D and 2D NMR, high-resolution mass spectrometry, Marfey’s analysis, and NOESY correlations, confirmed their structures. The bioactivity of these compounds was tested against six fungal phytopathogens, and compounds 3 and 4 demonstrated strong efficacy, particularly against Zymoseptoria tritici, with compound 3 exhibiting the highest potency (EC₅₀: 11 nM). Both compounds also displayed significant antifungal activity against Botrytis cinerea and Colletotrichum acutatum, with compound 4 proving to be the most potent. Despite moderate cytotoxicity against the human cancer cell line HepG2, compounds 3 and 4 emerge as promising fungicides for combating Septoria tritici blotch, anthracnose, and gray mold.

中文翻译：

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Escuzarmycins A–D，控制小麦壳针孢斑病的强效生物杀菌剂


一项针对新型抗真菌代谢物的研究确定了链霉菌丙酮提取物对主要植物病原体的有效体外抗真菌活性。菌株 CA-296093。基于特征的分子网络揭示了该提取物中存在抗霉素相关化合物，从而分离出四种新化合物：escuzarmycins A–D ( 1 – 4 )。采用 1D 和 2D NMR、高分辨率质谱、Marfey 分析和 NOESY 相关性进行的广泛结构阐明证实了它们的结构。测试了这些化合物针对六种真菌植物病原体的生物活性，化合物3和4表现出强大的功效，特别是针对小麦发酵腐霉(Zymoseptoria tritici) ，其中化合物3表现出最高的效力 (EC ₅₀ : 11 nM)。两种化合物还对灰葡萄孢和锐角炭疽病表现出显着的抗真菌活性，其中化合物4被证明是最有效的。尽管对人类癌细胞系 HepG2 具有中等的细胞毒性，但化合物3和4成为对抗小麦斑枯病、炭疽病和灰霉病的有前景的杀菌剂。