Solid-Matrix Fluorescence Quenching of Benzo[E]Pyrene and (±)-Anti-Dibenzo[a,l]Pyrene Diolepoxide-DNA Adducts

Abstract

The solid-matrix fluorescence (SMF) quenching of benzo[e]pyrene and (±)-anti-dibenzo[a,l]pyrene-11,12-diol-13,14-epoxide ((±)-anti-DB[a,l]PDE)-DNA adducts with thallium nitrate (TlNO3) and sodium iodide (NaI) was examined and several SMF quenching models were developed. The SMF quenching data for B[e]P with either TlNO3 or NaI fit a two-independent-binding-site model. However, the SMF quenching of (±)-anti-DB[a,l]PDE-DNA adducts with TlNO3 fits a sphere of action model, but quenching with NaI was modeled with the two-independent-binding-site model. The data were compared with earlier SMF quenching data for 7,8,9,10-tetrahydroxytetrahydro-benzo[a]pyrene (tetrol I-1) and (±)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide ((±)-anti-BPDE)-DNA adducts. The interpretation of the SMF quenching data for the (±)-anti-DB[a,l]PDE-DNA adducts was distinctively different than the interpretation of the SMF quenching data for the (±)-anti-BPDE-DNA adducts. This initial study shows that SMF quenching has the potential to characterize polycyclic aromatic hydrocarbon-DNA adducts with different numbers of aromatic rings. In addition, the data indicated that external and intercalated DNA adducts interacted with heavy-atom salts in dissimilar fashions. The new SMF methodology developed is useful for the characterization of both polycyclic aromatic hydrocarbon-DNA adducts and metabolites from polycyclic aromatic hydrocarbons.