To evaluate the estrogenic activities of several chemicals such as 17 beta-estradiol (E2), rho-nonylphenol, bisphenol A, butylparaben, and combinations of these chemicals, we used recombinant yeasts containing the human estrogen receptor [Saccharomyces cerevisiae ER + LYS 8127]. We evaluated E2 was most active in the recombinant yeast assay, followed by rho-nonylphenol, bisphenol A, butylparaben. The combinations of some concentrations of 17-estradiol as a strong estrogen and bisphenol A or butylparaben as a weak estrogen showed additive estrogenic effects. Also, the combinations of some concentrations of nonlyphenol and butylparaben and combination of butylparaben and bisphenol A showed additive effects in the estrogenic activity. Therefore, the estrogenic activities of the combinations of two chemicals were additive, not synergistic.
Cloning, Molecular ; Estradiol/pharmacology ; Estrogens/classification/*pharmacology ; Estrogens, Non-Steroidal/*pharmacology ; Humans ; Kinetics ; Parabens/pharmacology ; Phenols/pharmacology ; Receptors, Estrogen/drug effects/*physiology ; Recombinant Proteins/drug effects/metabolism ; Saccharomyces cerevisiae/genetics

Aromatase is a key enzyme responsible for in vivo estrogen biosynthesis. Inhibition of the activity of the aromatase has become an alterative way for treatment of breast cancer. In this review, the structure and catalytic mechanism of the aromatase is briefly introduced followed by thorough review of the progress in the study of the steroidal and non-steroidal aromatase inhibitors. This review is focused on the natural compounds that exhibit the aromatase inhibition, which include flavonoids, xanthones, coumarins, and sesquiterpenes. The structure-activity relationship of these compounds is also discussed.
Androstenedione ; analogs & derivatives ; Antineoplastic Agents ; chemistry ; pharmacology ; therapeutic use ; Aromatase ; chemistry ; metabolism ; pharmacology ; Aromatase Inhibitors ; chemistry ; classification ; pharmacology ; therapeutic use ; Breast Neoplasms ; drug therapy ; Catalysis ; Coumarins ; chemistry ; pharmacology ; Estrogens ; biosynthesis ; Flavonoids ; chemistry ; pharmacology ; Humans ; Inhibitory Concentration 50 ; Nitriles ; chemistry ; pharmacology ; Sesquiterpenes ; chemistry ; pharmacology ; Structure-Activity Relationship ; Triazoles ; chemistry ; pharmacology ; Xanthones ; chemistry ; pharmacology