A cell-permeable chloro-quinolinone compound that selectively and covalently modifies Kelch-like ECH-associated protein 1 (Keap1)-Cys151 and represses Keap1 function and reduces Nrf2 (Nuclear factor E2-related factor 2)-Keap1 interaction. Shown to stabilize Nrf2 by inhibiting the Keap1-driven ubiquitination of Nrf2 and thereby activating the Nrf2-ARE (antioxidant response element) pathway (EC50 = 2.7uM in neuroblastoma IMR-32 cells). Offers protection against H2O2 induced oxidative stress, but unlike tert-butylhydroquinone AI-1 does not act as a free radical scavenger. Its anti-oxidant effects are mediated via Nrf2 induced antioxidant response. Does not affect mutant ARE where GC are substituted with AT within the core ARE sequence.