UPLC MS/MS Quantification of Primary Metabolites of Benzo[a]pyrene and Fluoranthene Produced In Vitro by Sole (Solea solea) Liver Microsomal Activation

Biotransformation pathways of PAHs in a flat fish, Solea solea, living in nurseries close to coastal areas and estuaries constitute a great challenge for the environmental risk. Among PAHs, Fluoranthene (Fluo) has a different chemical structure than benzoa]pyrene (BaP), and can influence its biotransformation pathways and genotoxic potential. The aim of this study was to bring some response elements about the in vitro metabolic activation of Fluo and BaP by sole liver microsomes. The quantification of several primary metabolites of BaP and Fluo produced in vitro, following a sole liver microsomal activation, was conducted using a sensitive analytical UPLC MS/MS method.

Four types of BaP metabolites (dihydrodiols, diones, OH-BaP, and 7,8-dihydro-epoxide), and three types of Fluo metabolites (2,3-dihydrodiol, 2,3-dione, and sum of OH-Fluo) were quantified. The concentration for which the metabolite production was maximal was of 40 μM and 100 μM for BaP and Fluo, respectively. The biotransformation rate was higher for Fluo (9.97%) than for BaP (6.69%).Whatever the PAH, dihydrodiols and phenols were the major metabolites produced accounting for, respectively, 50% and 30–40% for BaP, and 40 and 60% for Fluo. Despite some differences in conformation, both PAHs seem to be activated by similar pathways and the diol-epoxide appears as a predominant one.