Enantioselective Detection, Bioactivity, and Degradation of the Novel Chiral Fungicide Oxathiapiprolin

Abstract

Oxathiapiprolin is a novel chiral piperidine thiazole isooxazoline fungicide that contains a pair of enantiomers. An effective analytical method was established for the enantioselective detection of oxathiapiprolin in fruit, vegetable, and soil samples using ultraperformance liquid chromatography-tandem triple quadrupole mass spectrometry. The optimal enantioseparation was achieved on a Chiralpak IG column at 35 °C using acetonitrile and 0.1% formic acid aqueous solution (90:10, v/v) as the mobile phase. The absolute configuration of the oxathiapiprolin enantiomers was identified with the elution order of R-(−)-oxathiapiprolin and S-(+)-oxathiapiprolin by electron circular dichroism spectra. The bioactivity of R-(−)-oxathiapiprolin was 2.49 to 13.30-fold higher than that of S-(+)-oxathiapiprolin against six kinds of oomycetes. The molecular docking result illuminated the mechanism of enantioselectivity in bioactivity. The glide score (−8.00 kcal/mol) for the R-enantiomer was better with the binding site in Phytophthora capsici than the S-enantiomer (−7.50 kcal/mol). Enantioselective degradation in tomato and pepper under the field condition was investigated and indicated that R-(−)-oxathiapiprolin was preferentially degraded. The present study determines the enantioselectivity of oxathiapiprolin about enantioselective detection, bioactivity, and degradation for the first time. The Renantiomer will be a better choice than racemic oxathiapiprolin to enhance the bioactivity and reduce the pesticide residues at a lower application rate.

Simultaneous determination of nereistoxin insecticides in foods of animal origins by combining pH-dependent reversible partitioning with hydrophilic interaction chromatography-mass spectrometry

“…ILOD and ILOQ were defined as the concentrations with signal-to-noise (S/N) ratios of the quantifier ion intensities equal to 3 and 10, respectively 24 . The matrix-dependent LOQs (MLOQs) of the NIs were defined as the lowest concentration determined from the ILOQ of nereistoxin, injection volume, dilution rate, and nereistoxin conversion factor in the analytical method 25 . The nereistoxin conversion factors were calculated by dividing the molecular weight of nereistoxin (M.W.…”

Sub/supercritical Fluid Chromatography for Chiral Compounds Analysis

“…Rozdílné účinky enantiomerů biologicky aktivních látek v živých organismech jsou obecně známé 8 . Velká pozornost je věnována zejména odlišnému chování enantiomerů léčiv, pesticidů, nových psychoaktivních sloučenin (NPS) a jejich metabolitů [9][10][11][12][13][14][15][16][17][18] . V literatuře se uvádí, že v současné době je přibližně 60 % syntetických léčiv používaných v klinické praxi chirálních, přičemž 88 % z nich se používá ve formě racemátů 19 .…”

Resistance Risk and Novel Resistance-Related Point Mutations in Target Protein PiORP1 of Fluoxapiprolin in Phytophthora infestans

“…Oxathiapiprolin is the first member of OSBPIs developed by DuPont, and it has a unique site of action and a novel mechanism of action (binding to an oxysterol-binding protein). 8,9 It is considered an important milestone in the history of the discovery of fungicides because of its high antioomycete activity. 9−12 Oxathiapiprolin was registered in China in 2015 for the control of grape downy mildew, tomato late blight, cucumber downy mildew, pepper blight, potato late blight, Chinese cabbage downy mildew, and litchi downy blight (http://www.chinapesticide.org.cn/hysj/index.jhtml).…”