[Studies on 2-hydroxyestradiol 17-sulfate derived from fetoplacental unit: the antioxidant as a potential defense substance against preeclampsia].

The antioxidant 2-hydroxyestradiol 17-sulfate (2-OH-E2-17-S) was found to be present in the placenta and to prevent the onset of preeclampsia. From experiments using rats, 2-OH-E2-17-S was confirmed to be a highly functional compound with stronger antioxidant activity than α-tocopherol and to sustain its antioxidant activity. 2-OH-E2-17-S was confirmed to be produced in the placenta from its precursor, estradiol 17-sulfate (E2-17-S), which is derived from fetal testosterone sulfate (TS). Since the fetal adrenal gland has been shown to convert testosterone (T) into TS, the following metabolic pathway may exist during pregnancy: T→TS→E2-17-S→2-OH-E2-17-S. This fetoplacental pathway may contribute to the maintenance of healthy pregnancy. Details and the experimental outline of these discoveries are reported in this review.