Chemosphere. 2013 Nov;93(10):2523-7. doi: 10.1016/j.chemosphere.2013.09.052.
In this study, the bioactivity, acute toxicity and dissipation in vegetables of the individual enantiomers of the fungicide hexaconazole had been investigated. The optical pure single enantiomers were prepared and the bioactivity of (+)-, (-)- and rac-hexaconazole was tested using four target fungi including Colletotrichum gloeosporioides Penz, Alternaria solani, Alternaria mali Roberts and Monilinia fructicola. The results showed (-)-hexaconazole was always more active than (+)-hexaconazole with the fungicidal activity 11–13-fold higher to A. solani, A. mali Roberts and Monilinia fructicola, and 1.26-fold higher to C. gloeosporioides Penz. (-)-Hexaconazole also showed 1.3-fold higher acute toxicity to aquatic species Daphnia magna based on the 48 h EC50 values. There was obvious enantioselectivity in the dissipation in tomato with (-)-hexaconazole degraded faster resulting an enrichment of (+)-form, and the half-lives of (-)-hexaconazole and (+)-hexaconazole in tomato were 2.96 d and 3.38 d respectively, while it was not enantioselective in green pepper, in which the both enantiomers had the half-lives about 4.36 d. The findings are helpful for better environmental and ecological risk assessment of hexaconazole on an enantiomeric level.
本研究考察了杀菌剂己唑醇单个对映异构体在蔬菜中的生物活性、急性毒性和消解动态。制备了光学纯的单个对映异构体，并采用包括炭疽病菌（Colletotrichum gloeosporioides Penz）、番茄早疫病菌（Alternaria solani）、苹果腐烂病菌（Alternaria mali Roberts）和桃褐腐病菌（Monilinia fructicola）在内的 4 种靶标真菌来测试（+）-、（-）-和外消旋己唑醇的生物活性。结果表明，（-）-己唑醇的活性始终高于（+）-己唑醇，对番茄早疫病菌、苹果腐烂病菌和桃褐腐病菌的杀菌活性分别高 11-13 倍，对炭疽病菌的活性高 1.26 倍。基于 48 h EC50 值，（-）-己唑醇对水生生物大型溞的急性毒性也高出 1.3 倍。在番茄中，（-）-己唑醇的消解存在明显的对映体选择性，导致（+）-形式的富集，其半衰期为 2.96 d；（-）-己唑醇和（+）-己唑醇在番茄中的半衰期分别为 3.38 d 和 3.38 d，而在青椒中则没有对映体选择性，两者的半衰期均约为 4.36 d。这些发现有助于更好地从对映体水平评估己唑醇对环境和生态的风险。
