Prenylated Flavonoids Isolated from the Root of as Potent Antifungal Agents against .

, a traditional Chinese herb, produces a wide range of secondary metabolites with a broad spectrum of biological activities. In this study, we isolated six isopentenyl flavonoids from the roots of and evaluated their activities against phytopathogenic fungi. In vitro activities showed that kurarinone and sophoraflavanone G displayed broad spectrum and superior activities, among which sophoraflavanone G displayed excellent activity against tested fungi, with EC values ranging from 4.76 to 13.94 μg/mL. Notably, kurarinone was easily purified and showed potential activity against , , and with EC values of 16.12, 16.55, and 16.99 μg/mL, respectively. Consequently, we initially investigated the mechanism of kurarinone against . It was found that kurarinone disrupted cell wall components, impaired cell membrane integrity, increased cell membrane permeability, and affected cellular energy metabolism, thereby exerting its effect against . Therefore, kurarinone is expected to be a potential candidate for the development of plant fungicides.