Screening for a Fenpropidin Enantiomer with High Activity and Low Toxicity

Fenpropidin has been extensively used for managing fungal diseases in different crops. There is a lack of literature on the enantioselective bioactivity and toxicity of fenpropidin. This study aims to explore the enantioselective bioactivity and toxicity of fenpropidin. R-Fenpropidin exhibited more potent bioactivity against seven plant pathogens than S-fenpropidin. R-Fenpropidin was more effective than S-fenpropidin in inhibiting sclerotial production, affecting mycelial growth and morphology, increasing cell membrane permeability, and decreasing the ergosterol content of Rhizoctonia solani. R-Fenpropidin exhibited a tighter binding affinity and formed hydrogen bonds with two target proteins. Fenpropidin also has enantioselective toxicity to Selenastrum capricornutum, with the toxicity of S-fenpropidin being seven times that of R-fenpropidin. S-Fenpropidin significantly reduced the content of the photosynthetic pigments. The results showed that R-fenpropidin was a highly active enantiomer with low toxicity. This study can provide a basis for the development of enantiomers with high activity and low toxicity.