Improved antifungal activity and reduced aquatic toxicity of fludioxonil by complexation with β-cyclodextrin

Poor water solubility results in limited fungicidal bioavailability and poses a great risk to non-target organisms due to the use of organic solvent in formulation processing. Here, the water solubility of fludioxonil (Flu) was improved by generating an inclusion complex with β-cyclodextrin (β-CD) at 1:1 host-guest stoichiometric ratio. The formation of the inclusion complex was confirmed by SEM, XRD, FT-IR, DSC, and 1 H-NMR spectra. Molecular docking simulation found that Flu was imbedded into the β-CD cavity, folded, and centrally aligned inside. In addition, Flu/β-CD displayed increased soil mobility, sustained release behavior, and a 2.75-fold increase of the fungicidal activity against Botrytis cinerea . Importantly, the prepared inclusion complex exhibited decreased acute toxicity to phytoplankton ( Chlorella vulgaris ), zooplankton ( Daphnia magna ), and fish ( Danio rerio ) than technical Flu. This study provided useful information for the rational use of Flu in agriculture, as well as the reduction of ecological risk to the aquatic environment.