OXIDATION OF QUINOLINE BY RABBIT LIVER

¹ Department of Pathology, The Western Pennsylvania Hospital, Pittsburgh, Pennsylvania

Quinoline, carbostyril, and 3-quinolinol were incubated aerobically with 9000 and 100,000 x g supernatants of rabbit liver without added NADPH2 (conditions favorable to aldehyde oxidase activity) and with washed microsomes and 9000 x g supernatant with added or generated NADPH₂ (conditions favorable to non-specific microsomal hydroxylation). While carbostyril and 3-quinolinol were the major metabolites of separated aldehyde oxidase and microsomal hydroxylating activities, respectively, the major product obtained in the presence of both enzyme activities and NADPH₂ was 6-hydroxycarbostyril. Carbostyril was rapidly converted to the same product by either washed microsomes or 9000 x g supernatant and NADPH₂. Five metabolites have been detected on chromatograms of extracts of incubation mixture of 3-quinolinol and NADPH₂ with 9000 x g super natant, one of which has been tentatively identifield as 3-hydroxy-4(1H)-quinolone. 3-Hydroxycarbostyril has not been observed. The ease with which quinoline and several oxygen substituted quinolines undergo microsomal hydroxylation is a function of their chloroform-water partitions.