Isolating Antipathogenic Fungal Coumarins from and Determining Their Primary Mechanism .

Through bioassay-guided isolation, eight undescribed coumarins (-), along with six reported coumarins (-), were obtained from The new structures were determined by using IR, UV, NMR, HRESIMS, and ECD calculations. The results of the biological activity assays showed that compound exhibited broad spectrum antifungal activities against all tested fungi and a significant inhibitory effect on with an EC value of 3.00 μg/mL. Notably, compound demonstrated greater curative and protective effects against tobacco balack shank than those of osthol . Thus, was structurally modified to obtain new promising antifungal agents, and the novel derivatives (, , and ) exhibited better effects on than did lead compound . Preliminary mechanistic exploration illustrated that could enhance cell membrane permeability, destroy the morphology and ultrastructure of cells, and reduce the exopolysaccharide content of mycelia. Furthermore, the cytotoxicity results revealed that compound exhibited relatively low cytotoxicity against HEK293 cell lines with an inhibition rate of 33.54% at 30 μg/mL. This research is promising for the discovery of new fungicides from natural coumarins with satisfactory ecological compatibility.