Selected plant extracts and female fertility: role in the regulation of the hypothalamo-pituitary-ovarian axis in normal and pathological conditions

Female infertility, which affects 10–20% of couples worldwide, is a growing health concern in developing countries. It can be caused by multiple factors, including reproductive disorders, hormonal dysfunctions, congenital malformations and infections. In vitro and in vivo studies have shown that plant extracts regulate gonadotropin-releasing hormone, kisspeptin, and gonadotropin expression and/or secretion at the hypothalamic–pituitary level and modulate somatic and germ cells, such as steroidogenesis, proliferation, apoptosis, and oxidative stress at the ovarian level. In this review, we report evidence for the role of certain plant extracts or plant bioactive compounds in the regulation of the hypothalamic–pituitary-ovary axis and, consequently, for the treatment of female infertility. We will also summarize their possible involvement in ovarian disorders such as polycystic ovary syndrome (PCOS), premature ovarian failure (POF) and ovarian cancers.