New conjugated metabolites of 3‐phenoxybenzoic acid in plants

The metabolism of 3‐phenoxybenzoic acid, a common plant metabolite of deltamethrin, cypermethrin and fenvalerate, has been studied in abscised leaves of cabbage, cotton, cucumber, kidney bean and tomato plants. The [ 14 C]‐acid was readily converted into more polar conjugates by esterification with glucose, 6‐O‐malonylglucose, gentiobiose, cellobiose, glucosylxylose and two types of triglucose with different isomerism. Other metabolites identified were the glucosyl ether of 3‐(4‐hydroxyphenoxy)benzoic acid, and a 3‐(2‐hydroxyphenoxy)benzoic acid derivative with a total of two molar equivalents of glucose linked to the carboxyl and phenolic ‐OH groups. The conjugation pathways were somewhat plant‐specific. The glucosylxylose ester was found only in cotton, and the cellobiose and triglucose esters were found only in tomato. All of the conjugates except the glucose and glucosylxylose esters were plant metabolites that had not been identified previously. Furthermore, this is the first report to show the presence of cellobiose and triglucose conjugates in plants. However, neither of the acetyl derivatives of the [ 14 C]‐triglucoside was identical with the synthetic deca‐acetyl derivative of [1→6]‐triglucoside.