CYP17A1 and polycystic ovary syndrome: In addition, quercetin decreases the expression of the 17α-hydroxylase/C17-20-lyase (CYP17; Cyp17a1) gene to reduce the activity of its enzyme (the critical enzyme that converts progesterone to androgens) (Shah and Patel, 2016) and regulates the state of androgen receptor (AR) binding to the specific sequence of C-type natriuretic peptide (CNP)/natriuretic peptide receptor 2 (NPR2) gene promoters (Zheng et al., 2022), thereby restoring the normal meiosis of oocytes and improving the state of high androgen and anovulation in patients with PCOS.