Dibenz[a,j]acridine metabolism: identification of in vitro products formed by liver microsomes from 3-methylcholanthrene-pretreated rats

The metabolism of the carcinogenic pentacyclic azaaromatic compound,dibenz[a,j]acridine, has been examined in liver microsomal incubationsusing preparations from 3-methylcholanthrene-pretreated Wistarrats. Using authentic synthetic standards, u.v. spectroscopyand mass spectrometry, the following were proved to be metabolites:trans-5, 6-dihydro-5, 6-dihydroxydibenz[a,j]acridine, trans-3,4-dihydro-3, 4-dihydroxydibenz[a,j]acridine, dibenz[a,j]acridine-5,6-oxide, 3-hydroxydibenz[a,j]acridine and 4-hydroxydibenz[a,j]acridine.The 3, 4-dihydrodiol appeared to be the major metabolite. Thesecondary metabolites were also examined and evidence is presentedfor the additional formation of dibenz[a,j]acridine-5, 6, 8,9-dioxide,tetrols, diol epoxides and phenolic dihydrodiols.