Phytochemicals as modulators of hormone physiology

Cessation of ovarian hormone production can severely compromise the well being of women by symptoms like hot flushes, sleeplessness, and osteoporosis. In addition, a significant number of menopausal women develop an obese stature often in association with insulin resistance. Menopausal symptoms are conventionally treated by hormone replacement therapy, posing an increased risk for the development of breast and endometrial cancer. Alternative treatment options discussed are prescribed medicinal plant products or nutritional supplements. Those often lack sufficient information about their biological effectiveness needed for the assessment of their efficacy and safety. In addition, new products are needed. Here we predominantly report on the characterization of products which are available on the market but also give an example of our screening results. For the medicinal plant extract of Rheum rhaponticum, we give an update on its uterine effects in the ovariectomized rat model, since we previously showed that the extract and hydroxystilbenes contained therein predominantly stimulate the estrogen receptor-β. For soy isoflavones we address the conversely discussed question of their biological effects following chronic lifelong exposure. We show that a consecutive exposure throughout fetal, neonatal and adult life significantly impacts on the physiology of treated animals during all developmental stages investigated. Since obesity and insulin resistance may additionally create a problem in elderly we screened for compounds capable to activate PPAR-γ, a well known mediator of insulin sensitivity. We show that extracts from Cistus salvifolius may serve this purpose. In conclusion, the combination of physiological and pharmacological tools enables us to identify and characterize phytochemicals potentially useful in menopausal applications as well as to test them for their efficiency and safety.