Duan Jinsheng, Sun Mingna, Shen Yang, Gao Beibei, Zhang Zhaoxian, Gao Tongchun, Wang Minghua
Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
Institute of Plant Protection and Agro-Product Safety, Anhui Academy of Agricultural Sciences, Key Laboratory of Agro-Product Safety Risk Evaluation (Hefei), Ministry of Agriculture, Hefei, 230031, People's Republic of China.
Bull Environ Contam Toxicol. 2018 Nov;101(5):651-656. doi: 10.1007/s00128-018-2474-6. Epub 2018 Oct 25.
The stereoselective herbicidal bioactivity and toxicity toward aquatic organisms of carfentrazone-ethyl enantiomers were investigated. The results showed that there was significant enantioselective acute toxicity toward Selenastrum bibraianum. In addition, S-(-)-carfentrazone-ethyl was 4.8 times more potent than R-(+)-isomer. However, a slight enantioselectivity was observed for Daphnia magna and Danio rerio. The stereoselective herbicidal bioactivity of carfentrazone-ethyl enantiomers was observed by assessing maize root-length inhibition. The results clarified that S-(-)-carfentrazone-ethyl (EC 1.94 mg/L) > Rac-carfentrazone-ethyl (EC 2.18 mg/L) > R-(+)-carfentrazone-ethyl (EC 3.96 mg/L). The herbicidal bioactivity of S-(-)-carfentrazone-ethyl was 2 times higher more than R-(+)-isomer. The mechanism of enantioselective bioactivity was illustrated using molecular simulation software. The GlideScore energies of S-(-)-carfentrazone-ethyl and R-(+)-carfentrazone-ethyl were - 6.15 kcal/mol and - 5.59 kcal/mol, indicating that the S-form has a greater affinity to the active site of protoporphyrinogen oxidase, which is consistent with the results of the bioactive assay. This study can rise the significance of risk assessments for carfentrazone-ethyl herbicide.
研究了精恶唑禾草灵对映体的立体选择性除草生物活性及其对水生生物的毒性。结果表明，其对斜生栅藻具有显著的对映体选择性急性毒性。此外，S-(-)-精恶唑禾草灵的毒性是R-(+)-异构体的4.8倍。然而，对大型溞和斑马鱼仅观察到轻微的对映体选择性。通过评估玉米根长抑制情况，观察了精恶唑禾草灵对映体的立体选择性除草生物活性。结果表明，S-(-)-精恶唑禾草灵（EC 1.94 mg/L）＞消旋精恶唑禾草灵（EC 2.18 mg/L）＞R-(+)-精恶唑禾草灵（EC 3.96 mg/L）。S-(-)-精恶唑禾草灵的除草生物活性比R-(+)-异构体高2倍。使用分子模拟软件阐明了对映体选择性生物活性的机制。S-(-)-精恶唑禾草灵和R-(+)-精恶唑禾草灵的GlideScore能量分别为-6.15 kcal/mol和-5.59 kcal/mol，表明S型对原卟啉原氧化酶活性位点具有更高的亲和力，这与生物活性测定结果一致。本研究可提高精恶唑禾草灵除草剂风险评估的重要性。
