Benz[j]aceanthrylene: a novel polycyclic aromatic hydrocarbon with bacterial mutagenic activity

Area of Science:

• Environmental Chemistry
• Toxicology
• Molecular Biology

Background:

• Polycyclic Aromatic Hydrocarbons (PAHs) are environmental contaminants with known mutagenic properties.
• Cyclopenta-fused PAHs represent a class of compounds with less understood toxicological profiles.
• Benz[j]aceanthrylene is a novel cyclopenta-PAH requiring investigation into its biological activity.

Purpose of the Study:

• To investigate the mutagenicity of benz[j]aceanthrylene using the Salmonella (Ames) bacterial assay.
• To elucidate the metabolic activation requirements and identify key metabolites of benz[j]aceanthrylene.
• To compare the mutagenic profile of benz[j]aceanthrylene with a known mutagen, benzo[a]pyrene.

Main Methods:

• Utilized the Salmonella Ames tester strains (5 strains) to assess mutagenicity.
• Determined dose-response curves, particularly for strain TA98.
• Investigated the requirement for metabolic activation using S9 fraction.
• Analyzed metabolites, focusing on the identification of the 1,2-dihydro-1,2-diol.

Main Results:

• Benz[j]aceanthrylene demonstrated mutagenic activity across the Ames tester strains, similar to benzo[a]pyrene.
• The compound acts as a frame-shift mutagen, necessitating metabolic activation.
• Optimal mutagenic activity was observed at significantly lower S9 concentrations compared to benzo[a]pyrene.
• The 1,2-dihydro-1,2-diol was identified as the predominant metabolite, suggesting the 1,2-oxide as the ultimate mutagen.

Conclusions:

• Benz[j]aceanthrylene is a mutagenic cyclopenta-PAH with a toxicological profile comparable to benzo[a]pyrene.
• The compound exhibits high mutagenic potency at low metabolic activation concentrations.
• Metabolism via the 1,2-oxide is implicated in the mutagenicity of benz[j]aceanthrylene.