Electrophilic and Reactive Oxygen Species Detoxification Potentials of Chalcone Dimers is Mediated by Redox Transcription Factor Nrf-2

Nuclear erythroid related factor-2 (Nrf2), a redox-transcription factor, plays a critical role in the detoxification of electrophilic and reactive oxygen species that halt various biochemical and molecular processes. This makes it a candidate for regulation by polyphenols. This study investigates the capability of chalcone dimers (lophirones B and C) to induce expressions and activities of cytoprotective enzymes. Chalcone dimers administration to rats not only induced the Nrf2, but also suppressed cytoplasmic Kelch-like ECH-associated protein 1 (Keap1) expressions. In addition, the chalcone dimers significantly (p < 0.05) increased the expressions and activities of nicotinamide adenine dinucleotide and reduced quinone oxidoreductase-1, glutathione-S-transferase, epoxide hydrolase and uridyl glucuronosyl transferase in rat liver. Also, activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in rat liver increased significantly (p < 0.05). Overall, lophirones B and C increased the expressions and activities of cytoprotective proteins in rat liver possibly through the reduction of cytoplasmic Keap1 expression, leading to the nuclear translocation of Nrf2. (C) 2013 Wiley Periodicals, Inc.