Effects of isoliquiritigenin on ovarian antral follicle growth and steroidogenesis

•Isoliquiritigenin inhibits antral follicle growth.•Isoliquiritigenin alters estradiol, testosterone, and progesterone levels.•Isoliquiritigenin increases Star mRNA levels, but inhibits Cyp17a1, Cyp19a1, and Hsd17b1 mRNA levels.

Isoliquiritigenin is a botanical estrogen used as a dietary supplement. Previous studies show that other botanical estrogens affect ovarian estradiol synthesis, but isoliquiritigenin's effects on the ovary are unknown. Thus, this study tested the hypothesis that isoliquiritigenin inhibits ovarian antral follicle growth and steroidogenesis. Antral follicles from CD-1 mice were cultured with vehicle control (dimethyl sulfoxide; DMSO) or isoliquiritigenin (0.6 μM, 6 μM, 36 μM, and 100 μM) for 48-96 h. During culture, follicle diameters were measured daily to assess follicle growth. After culture, media were collected for hormone assays and follicles were collected for gene expression analysis of steroidogenic enzymes. Isoliquiritigenin inhibited antral follicle growth and altered estradiol, testosterone, and progesterone levels. Additionally, isoliquiritigenin altered the mRNA levels of cytochrome P450 steroid 17-α-hydroxylase 1, aromatase, 17β-hydroxysteroid dehydrogenase 1, and steroidogenic acute regulatory protein. These data indicate that exposure to isoliquiritigenin inhibits growth and disrupts steroid production in antral follicles.