Antifungal phloroglucinol derivatives from Dryopteris fragrans (L.) Schott

Potatoes, a major economic crop, are significantly impacted by Fusarium dry rot, a prevalent postharvest disease. In Dryopteris fragrans, the research of phloroglucinol derivatives are mainly focused on antibacterial activity, while the inhibitory effects on phytopathogenic fungi have not been reported.

In our study, six new phloroglucinol derivatives, Ortho-desaspidin AA (1), Ortho-desaspidin PA (2), Ortho-desaspidin BA (3), Dryaspidin B (4), Alde-iso-methylaspidinol B (5), and Iso-methylaspidinol P (6), and nine known phloroglucinol derivatives, were isolated from D. fragrans. And Compound 10, aspidinol B, showed significant inhibitory activity against Fusarium oxysporum, Fusarium graminearum, Fusarium proliferatum with EC₅₀ = 3.619, 6.051, and 8.221 μg/mL, respectively, outperforming the commercial fungicide hymexazol (EC₅₀ = 34.88, 8.21, 17.91). Aspidinol B displayed potent in vivo antifungal activity against F. oxysporum, F. graminearum, and F. proliferatum at 10 μg/mL with an inhibitory rate of 83.26, 54.15 and 79.62%, respectively. Transcriptome analysis speculates that aspidinol B, by affecting the uptake of iron ions into the bacterium, and cause heme depletion that ultimately leads to changes in oxidation-related pathways.

Aspidinol B exhibits strong inhibitory effects on Fusarium, indicating its potential use in the prevention and control strategies for potato dry rot. These results indicate that aspidinol B could be a potential fungicidal lead compound against Fusarium. © 2025 Society of Chemical Industry.