Hydrophobicity, 3D complexity, and steric feature affect salicylate inhibition of human and rat gonadal 3β-hydroxysteroid dehydrogenases: Insights from experiments to 3D-QSAR and in silico docking analysis

Salicylates (SEs) are a diverse group of compounds with wide-ranging applications and potential endocrine-disrupting properties. This study investigated how structural features of SEs govern their inhibition of human 3β-hydroxysteroid dehydrogenase 2 (h3β-HSD2) in KGN cells and rat testicular 3β-HSD1 (r3β-HSD1), assessing progesterone secretion. SE hydrophobicity and steric bulk strongly correlated with inhibitory potency [IC 50 range: ethylhexyl SE (20.93 μM) to aspirin (103.43 μM) for h3β-HSD2 or ethylhexyl SE (56.50 μM) to phenyl SE (143.01 μM) for r3β-HSD1] with mixed/noncompetitive inhibition. Notably, ethylhexyl, homomenthyl, and benzyl SEs significantly suppressed progesterone secretion in KGN cells at concentrations as low as 1 μM. Docking analysis suggested SE binding near NAD + /steroid sites. Bivariate correlation linked higher pIC 50 to higher hydrophobicity (LogP, apolar desolvation energy), 3D complexity (Fsp 3 , molecular volume), and steric feature (Sterimol L). 3D-QSAR identified key interaction regions (hydrophobic regions), with ethylhexyl SE engaging most regions, unlike aspirin. This study first combined experimental and in silico analysis of SE-3β-HSD interactions.