Salicylate esters inhibit human and rat 11β-Hydroxysteroid dehydrogenase type 2: Mechanistic insights from enzyme kinetics, SPR, and molecular modeling.

Salicylate esters are widely used in foods, pharmaceuticals, and cosmetics, but their effects on 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), a key enzyme in cortisol metabolism and placental glucocorticoid protection, remain unclear. We investigated the inhibitory effects of 15 salicylate esters on human and rat 11β-HSD2 using enzyme kinetics, SPR, cellular assays, SAR/QSAR, docking, molecular dynamics, and network toxicology. Benzyl salicylate was the most potent inhibitor, with IC50 values of 18.53 μM for human and 29.25 μM for rat 11β-HSD2. Global nonlinear fitting with AICc-based model comparison supported predominantly noncompetitive or mixed/noncompetitive inhibition of human 11β-HSD2 with respect to cortisol, whereas rat 11β-HSD2 showed compound-dependent apparent inhibition patterns; Lineweaver-Burk plots were retained only for visualization. SPR showed direct binding of benzyl and homomenthyl salicylates to human 11β-HSD2, with KD values of 21.6 and 47.4 μM, respectively, and suggested that benzyl salicylate interferes with NAD+ binding. Docking localized active salicylates near the NAD+/steroid interface, and molecular dynamics supported complex stability. In BeWo cells, active salicylates reduced cortisone production under largely noncytotoxic conditions, supporting impaired cortisol metabolism in intact cells. SAR and 3D-QSAR analyses identified lipophilicity, steric features, and aromaticity as major determinants of potency, while exploratory network toxicology suggested possible links to placental function and fetal growth-related pathways. These findings identify salicylate esters as 11β-HSD2 inhibitors and provide mechanistic evidence for their potential interference with glucocorticoid metabolism in vitro.