Study on the Antifungal Activity and Mechanism of Flavonoids from Cortex mori against Botrytis cinerea

The widespread emergence and increasing prevalence of multidrug-resistant phytopathogenic strains have accelerated the exploration of novel, eco-friendly antimicrobial agrochemicals. In this study, seven flavonoids were isolated from Cortex mori, and their antifungal activities were comprehensively evaluated. In vitro bioassays demonstrated that Albanol B exerted broad-spectrum inhibitory effects against six phytopathogenic fungi, with EC 50 values ranging from 5.30 to 39.8 μg/mL. Notably, Albanol B displayed potent anti- Botrytis cinere a activity with an EC 50 of 5.30 μg/mL, which was superior to that of kresoxim-methyl (32.7 μg/mL). Mechanistic studies elucidated that Albanol B markedly suppressed spore germination, damaged cell wall structure, and impaired the integrity and permeability of the cell membrane. Drug affinity responsive target stability (DARTS) analysis further validated that Albanol B inhibited the activities of triosephosphate isomerase and transaldolase, leading to fungal death by disrupting energy metabolism. Furthermore, in vivo experiments confirmed that Albanol B possessed outstanding protective and curative effects against fungal diseases in apples and tomatoes, as well as a good safety profile. Consequently, Albanol B emerged as a promising candidate for developing novel plant-based fungicides.