Potent and selective NADPH oxidase 1 (NOX1) inhibitor (IC50 = 20 nM). Exhibits selectivity for NOX1 over NOX2, NOX4, NOX5 and xanthine oxidase. Inhibits NOX1-derived O2- production in HT-29 human colon cancer cells. Attenuates VEGF-induced human pulmonary artery endothelial cell migration under hypoxic conditions in vitro. Cell permeable.