Azole fungicides inhibit human and rat gonadal 3ß-hydroxysteroid dehydrogenases: Structure-activity relationship and in silico docking analysis.

ABSTRACT

Azole fungicides are widely used in the agricultural industry to control fungal infections in crops. However, recent studies have shown that some azole fungicides inhibit the activity of 3ß-hydroxysteroid dehydrogenases (3ß-HSDs) in the gonads. Out of the 16 azole fungicides tested, 8 were found to inhibit human KGN cell 3ß-HSD2 with IC50 values of less than 100 µM. The strongest inhibitor was difenoconazole, with an IC50 value of 1.88 µM. In contrast, only 3 of the azole fungicides inhibited rat testicular 3ß-HSD1, which was less sensitive to inhibition. Azole fungicides potently inhibited progesterone secretion by KGN cells under basal and forskolin stimulated conditions at ≥ 5 µM. The inhibitory strength of azole fungicides was determined by their lipophilicity (LogP), molecular weight, pKa, and binding energy. A pharmacophore analysis revealed that the hydrogen bond acceptor-lipid group was a critical feature required for inhibition. Overall, these findings suggest that the use of azole fungicides have unintended consequences on reproductive health due to their inhibition of gonadal 3ß-HSDs. Key words Azole fungicides; steroid hormones; 3ß-hydroxysteroid dehydrogenase; docking analysis; lipophilicity.