2-hydroxy Estrone is an active metabolite of the endogenous estrogen estrone .1 It 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.2 It 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)