Zhang Xin, Gao Ming, Dong Yajie, Pan Le, Zhai Manjun, Jin Lu
College of Chemistry and Chemical Engineering, Xinjiang Agricultural University, Urumqi, 830052, China.
College of Animal Sciences, Xinjiang Agricultural University, Urumqi, 830052, China.
Chem Biodivers. 2024 Dec;21(12):e202401390. doi: 10.1002/cbdv.202401390. Epub 2024 Oct 21.
Structural modification is an effective way to improve the antifungal activity of natural products and has been widely used in the development of novel fungicides. In this work, a series of aminocoumarin-based Schiff bases were synthesized and characterized by H-NMR, C NMR and HR-MS spectra. The in vitro inhibition activity of all compounds was tested against four phytopathogenic fungi (Alternaria solani, Fusarium oxysporum, Botrytis cinerea, and Alternaria alternata) using the mycelial growth rate method. The results showed that most of the target compounds exhibited significant antifungal activities. In particular, compounds 5b, 5c, 5d, 5h, 5n, 7c, 7n, and 7p exhibited more effective antifungal activity than commercially available fungicides, chlorothalonil and azoxystrobin. The structure-activity relationship revealed that the electron-withdrawing groups with more electronegativity introduced at the C-3 position were effective in improving the inhibitory activity and that halogenated benzaldehydes would be necessary in the preparation of Schiff bases. The compound 5n against Fusarium oxysporum (EC=8.73 μg/mL) and the compound 7p against Alternaria alternata (EC=26.25 μg/mL) were much better than the positive controls (chlorothalonil and azoxystrobin). Therefore, compounds 5n and 7p could serve as promising lead compounds for the development of novel broad-spectrum fungicides, which could be useful for applications in the agriculture.
结构修饰是提高天然产物抗真菌活性的有效方法，已广泛应用于新型杀菌剂的开发。在本研究中，合成了一系列基于氨基香豆素的席夫碱，并通过氢核磁共振谱、碳核磁共振谱和高分辨质谱进行了表征。采用菌丝生长速率法测试了所有化合物对四种植物病原真菌（茄链格孢、尖孢镰刀菌、灰葡萄孢和链格孢）的体外抑制活性。结果表明，大多数目标化合物表现出显著的抗真菌活性。特别是，化合物5b、5c、5d、5h、5n、7c、7n和7p表现出比市售杀菌剂百菌清和嘧菌酯更有效的抗真菌活性。构效关系表明，在C-3位引入吸电子能力更强的基团对提高抑制活性有效，且在席夫碱的制备中卤代苯甲醛是必要的。化合物5n对尖孢镰刀菌（EC = 8.73 μg/mL）和化合物7p对链格孢（EC = 26.25 μg/mL）比阳性对照（百菌清和嘧菌酯）效果要好得多。因此，化合物5n和7p可作为开发新型广谱杀菌剂的有前景先导化合物，有望应用于农业领域。
