Enantioseparation, Absolute Configuration, and Enantioselective Bioactivity Mechanism of the Chiral Fungicide Nuarimol

In this study, the nuarimol enantiomers were successfully baseline separated with Rs 1.70 by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The absolute configurations of the nuarimol enantiomers were confirmed as R-(+)-nuarimol and S-(-)-nuarimol. The enantioselective bioactivity assay indicated that R-(+)-nuarimol exhibited greater potency against seven phytopathogenic fungi, with values approximately 1.4-3.5 and 4.5-51.4 times higher than those of rac-nuarimol and S-(-)-nuarimol. The active contribution value of R-enantiomer was 82-98%, showing that R-(+)-nuarimol played a crucial role in bioactivity. Meanwhile, R-(+)-nuarimol exhibited stronger effects in increasing the cell membrane permeability, compromising the cell membrane integrity, and inhibiting ergosterol biosynthesis. Molecular docking analysis showed that R-(+)-nuarimol possessed a stronger binding affinity to sterol 14-α demethylase (CYP51) than S-(-)-nuarimol, with docking energies of -7.42 and -7.36 kcal/mol. This study contributes essential data for screening a high-activity enantiomer of nuarimol and provide guidance for reducing used dosage and increasing the efficiency of nuarimolAQ.