4'-hydroxy Chalcone is a chalcone metabolite with diverse biological activities. It is formed when chalcone is metabolized by the cytochrome (CYP) P450 isoform CYP1A1 or CYP2C6.{40121} 4'-hydroxy Chalcone is estrogenic in MCF-7 cells and is cytotoxic at concentrations higher than 100 nM. It inhibits TNF-a-induced NF-kB signaling and the trypsin-, chymotrypsin-, and caspase-like proteolytic activities of the 26S proteasome in K562 cells in a dose-dependent manner.{40122} 4'-hydroxy Chalcone reduces growth of K562, U937, and Jurkat cancer cell lines in a dose-dependent manner without effecting viability of peripheral blood mononuclear cells (PBMCs). It also inhibits glutathione reductase (GSH-RD; IC50 = 47.3 ?M) in vitro in a reversible and non-competitive manner.{40123}