In silico, in vitro, and in vivo profiling of endocrine activity and toxicity of selected oxygenated polycyclic aromatic compounds frequently encountered in PAH-contaminated soils

Oxygenated polycyclic aromatic compounds (O-PACs) are ubiquitous environmental contaminants whose toxicological profiles remain poorly characterized. Using an integrated in silico, in vitro, and in vivo approach, this study provides a comprehensive assessment of endocrine activity, toxicity, and developmental effects for eleven structurally diverse O-PACs, including one oxygen-substituted aromatic compound and ten ketones (carbonyl-containing O-PACs). These three methodological tiers provide complementary yet distinct insights. In silico modeling predicted interactions of several higher-ring O-PACs with estrogen (ER) and androgen (AR) receptors, but not with the glucocorticoid receptor (GR). Consistent with these predictions, in vitro cell-based assays revealed limited ER activity for a few compounds, anti-AR activity for 8 out of 11 O-PACs, and no GR activity. The experimental assays further showed no androgenic activity or genotoxicity, weak pregnane X receptor (PXR)-mediated activity for two compounds, and aryl hydrocarbon receptor (AhR)-mediated activity after 4 h exposure for six O-PACs. Of these six, three O-PACs (5,12-naphthacenequinone, 11H-benzo[a]fluoren-11-one, and 1,2-benzanthraquinone) remained active after 24 h, with responses approaching those of benzo[a]pyrene (B[a]P). In vivo, these three compounds induced acute toxicity and developmental defects in zebrafish embryos, including pericardial oedema and impaired motility. They also induced, via dedicated assays using transgenic zebrafish, strong anti-ER and AhR-mediated activities at lower non-toxic concentrations. Overall, these results demonstrate that O-PACs can elicit diverse receptor-mediated and developmental effects, with some derivatives matching or exceeding B[a]P activity. The convergence of mechanistic and organism-level responses highlights the value of such a multi-tiered approach for improving hazard characterization and supports the need for increased environmental and regulatory attention toward O-PAC contaminants.