Abstract
Metabolism in cabbage plants of (1R)-cis- and (1R)-trans-isomers of cypermethrin [(RS)-α-cyano-3-phenoxybenzyl (1RS)-cis, trans-3-(2, 2-dichlorovinyl)-2, 2-dimethylcyclopropanecarboxylate] was investigated with 14C preparations labeled separately in the benzylphenyl ring and cyclopropyl ring. The half-life of disappearance was about 4-5 days and 7-8 days for trans- and cis-cypermethrin, respectively. Both isomers of cypermethrin underwent epimerization to (1S)-isomers, cis/trans isomerization, ester bond cleavage, hydroxylation of the phenoxy group in the alcohol moiety or the geminal methyl group in the acid moiety, hydration of the CN group to the CONH2 group with subsequent hydrolysis to the COOH group, and conjugation of the resultant carboxylic acids and alcohols with sugars. The major metabolites from the alcohol moiety were glycoside conjugates of 3-(4-hydroxyphenoxy) benzoic acid and 3-phenoxybenzoic acid, and glycoside conjugates of 3-(2, 2-dichlorovinyl)-2, 2-dimethylcyclopropanecarboxylic acid from the acid moiety. Cypermethrin and its metabolites hardly translocated from the treated leaves to other parts of the plants.
