Discovery of novel flavonoid derivatives containing benzothiazole as potential antifungal agents

Background: Fungal diseases of plants have a serious impact on the quality and yield of crops, and some traditional pesticides can no longer cope with this problem. Therefore, it is of great significance to develop new pesticides with high efficiency and low toxicity.

Results: A series of flavonoid derivatives containing benzothiazole were designed and synthesized. Among them, the compounds V17, V12, and V13 had excellent inhibitory effect against Fusarium oxysporum f. sp. cucumerinu with the half-maximal effect concentration (EC₅₀) values of 1.2, 2.3, and 3.2 μg/mL, which were better than the control drug Kresoxim-methyl (Km, 37.8 μg/mL). The in vivo protective activity and curative activities of V17 against cucumber fusarium wilt caused by F. oxysporum f. sp. cucumerinum were 82.4 and 60.5% at 200 μg/mL, better than Km (60.2 and 48.6%). In addition, V17 could damage the cell membrane of the mycelia, which can be confirmed by determination of cytoplasmic leakage, detection of cell membrane permeability, and measurement of malondialdehyde (MDA). Similarly, the scanning electron microscopy (SEM) experiment and optical microscope characterization provide direct evidence for destruction of mycelium treated with V17.

Conclusion: V17 significantly reduced the pathogenicity of the F. oxysporum f. sp. cucumerinum, which provided a new idea and direction for the development of green pesticides. © 2025 Society of Chemical Industry.