2-hydroxy Estrone is an active metabolite of the endogenous estrogen estrone .¹It is formed from estrone primarily by the cytochrome P450 (CYP) isoforms CYP1A2, CYP1A1, and CYP1B1 and metabolized to 2-methoxy estrone by catechol-O-methyltransferase (COMT). 2-hydroxy Estrone (10 µM) inhibits the proliferation of estrogen receptor-positive MCF-7, but not estrogen receptor-negative MDA-MB-231, breast cancer cells cultured with the COMT inhibitor quinalizarin.²It inhibits iron-ADP-adriamycin complex-induced lipid peroxidation of liposomes prepared from rat liver microsomes (IC₅₀= 2.7 µM).³

1.Cribb, A.E., Knight, M.J., Dryer, D., et al.Role of polymorphic human cytochrome P450 enzymes in estrone oxidationCancer Epidemiol. Biomarkers Prev.15(3)551-558(2006) 2.Schneider, J., Huh, M.M., Bradlow, H.L., et al.Antiestrogen action of 2-hydroxyestrone on MCF-7 human breast cancer cellsJ. Biol. Chem.259(8)4840-4845(1984) 3.Nakano, M., Sugioka, K., Naito, I., et al.Novel and potent biological antioxidants on membrane phospholipid peroxidation: 2-Hydroxy estrone and 2-hydroxy estradiolBiochem. Biophys. Res. Commun.142(3)919-924(1987)