The Metabolism of some Thioureidobenzene Fungicides in Mice and Sheep

Abstract

1. The metabolism of thiophanate, thiophanate methyl and related thioureidobenzene compounds has been studied in mice and sheep and in enzyme preparations from these species.

2. Both species catalyse transformation of the thiophanate compounds into the benzimidazole derivatives, ethyl benzimidazol-2-ylcarbamate or methyl benzimidazol-2-ylcarbamate and their 5(6)-hydroxyiation products. 2-Aminobenzimidazole and 5-hydroxy-2-aminobenzimidazole are also formed.

3. The in vitro metabolism to benzimidazole compounds required NADPH, and was inhibited by SKF 525A and carbon monoxide.

4. The hydroxylated metabolites were excreted from mice and sheep as glucuronide and sulphate conjugates. Benzimidazole derivatives were eliminated as conjugates to an extent of 9–14%.