Nordihydroguaiaretic Acid as a Novel Substrate and Inhibitor of Catechol Methyltransferase Modulates 4-Hydroxyestradiol-Induced Cyto- and Genotoxicity in MCF-7 Cells.

Nordihydroguaiaretic acid (NDGA) is a major lignan metabolite found in spp., which are widely used in South America to treat various diseases. In breast tissue, estradiol is metabolized to the catechol estrogens such as 4-hydroxyestradiol (4-OHE), which have been proposed to be cancer initiators potentially involved in mammary carcinogenesis.