Bromobenzene metabolic pathways

Williams (447) concludes from the available evidence that the most probable metabolic pathway of bromobenzene is simultaneous conjugation... 

Figure 7.22 Metabolism of bromobenzene. The bromobenzene 2,3-oxide and 3,4-oxide may undergo chemical rearrangement to the 2- and 4-bromophenol, respectively. Bromobenzene 3,4-oxide may also be conjugated with glutathione, and in its absence react with tissue proteins. An alternative detoxication pathway is hydration to the 3,4-dihydrodiol via epoxide hydrolase.

The metabolites 2- and 4- bromophenol can also be metabolized by a further oxidation pathway to yield catechols and quinones, some of which are cytotoxic and potentially hepatotoxic. Thus, in vitro studies have indicated that bromoquinones and bromocatechols may be responsible for some of the covalent binding to protein and reaction with glutathione. However, administration of primary phenolic metabolites does not cause hepatotoxicity. At least seven glutathione conjugates have been identified as metabolites of bromobenzene and its primary phenolic metabolites. 

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