Department of Applied Chemistry, China Agricultural University, Beijing, P.R. China.
Chirality. 2014 Jan;26(1):51-5. doi: 10.1002/chir.22265. Epub 2013 Nov 19.
Myclobutanil, (RS)-2-(4-chlorophenyl)-2-(1H-1, 2, 4-triazol-1-ylmethyl)hexanenitrile is a broad-spectrum systemic triazole fungicide which consists of a pair of enantiomers. The stereoselective degradation of myclobutanil was investigated in rat liver microsomes. The concentrations of myclobutanil enantiomers were determined by high-performance liquid chromatography (HPLC) with a cellulose-tris-(3,5-dimethyl-phenylcarbamate)-based chiral stationary phase (CDMPC-CSP) under reversed phase condition. The t(1/2) of (+)-myclobutanil is 8.49 min, while the t(1/2) of (-)-myclobutanil is 96.27 min. Such consequences clearly indicated that the degradation of myclobutanil in rat liver microsomes was stereoselective and the degradation rate of (+)-myclobutanil was much faster than (-)-myclobutanil. In addition, significant differences between two enantiomers were also observed in enzyme kinetic parameters. The V(max) of (+)-myclobutanil was about 4-fold of (-)-myclobutanil and the CL(int) of (+)-myclobutanil was three times as much as (-)-myclobutanil after incubation in rat liver microsomes. Corresponding consequences may shed light on the environmental and ecological risk assessment for myclobutanil and may improve human health.
戊菌唑，（RS）-2-（4-氯苯基）-2-（1H-1,2,4-三唑-1-基甲基）己腈，是一种广谱的内吸性三唑类杀菌剂，由一对对映异构体组成。本研究采用大鼠肝微粒体，考察了戊菌唑的立体选择性降解。在反相条件下，用纤维素三-（3,5-二甲基-对苯基氨基甲酸酯）-手性固定相（CDMPC-CSP）的高效液相色谱（HPLC），对戊菌唑对映异构体的浓度进行了检测。（+）-戊菌唑的 t(1/2)为 8.49 min，而（-）-戊菌唑的 t(1/2)为 96.27 min。这些结果清楚地表明，大鼠肝微粒体中戊菌唑的降解具有立体选择性，（+）-戊菌唑的降解速率明显快于（-）-戊菌唑。此外，两种对映异构体在酶动力学参数上也存在显著差异。（+）-戊菌唑的 V(max)约为（-）-戊菌唑的 4 倍，（+）-戊菌唑的 CL(int)是（-）-戊菌唑的 3 倍。这些结果可能为戊菌唑的环境和生态风险评估提供参考，并可能改善人类健康。
