Enantiomeric separation and toxicity of an organophosporus insecticide, pyraclofos.
Despite the fact that the biological processes of chiral pesticides are enantioselective, knowledge of the toxicities of pyraclofos due to enantiospecificity is scarce. In this study, the optical isomers of pyraclofos were separated and their toxicities to butyrylcholinesterase (BChE) and  Daphnia magna  were assessed. Baseline resolution of the enantiomers was obtained on both Chiralcel OD and Chiralpak AD columns. The effect of the mobile phase composition and column temperature were then discussed. The resolved enantiomers were characterized by their optical rotation and circular dichroism signs. The anti-BChE tests demonstrated that (-)-pyraclofos was about 15 times more potent than its (+)-form. However, acute aquatic assays suggested that (+)-pyraclofos was about 6 times more toxic than its antipode. Moreover, the joint toxicity of pyraclofos enantiomers to D. magna was found to be an additive effect. These results demonstrated that the overall toxicity of pyraclofos should be assessed using the individual enantiomers.
College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
Honghua
H
Zhang
Shengwen
S
Chen
Shanshan
S
Zhou
D000818:Animals; D002091:Butyrylcholinesterase; D002800:Cholinesterase Inhibitors; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D003621:Daphnia; D007306:Insecticides; D063086:Organothiophosphates / Q000737:chemistry / Q000302:isolation & purification* / Q000633:toxicity*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013816:Thermodynamics
D002800:Cholinesterase Inhibitors; D007306:Insecticides; D063086:Organothiophosphates; D002091:Butyrylcholinesterase; C069547:pyraclofos