Kazinol Q from Broussonetia kazinoki enhances cell death induced by Cu(ll) through increased reactive oxygen species

Abstract

The ability of the flavan kazinol Q (KQ) to induce DNA breakage in the presence of Cu(II) was examined by agarose gel electrophoresis using supercoiled plasmid DNA. In KQ-mediated DNA breakage reaction, the involvement of reactive oxygen species (ROS), H2O2 and O2- was established by the inhibition of DNA breakage by catalase and revealed DNA breakage by superoxide dismutase (SOD). The cell viability of gastric carcinoma SCM-1 cells treated with various concentrations of KQ was significantly decreased by cotreatment with Cu(II). Treatment of SCM-1 cells with 300 μM Cu(II) enhanced the necrosis induced by 100 μM KQ. Treatment of SCM-1 cells with 100 μM KQ in the presence of 300 μM Cu(II) increased the generation of H2O2. Taken together, the above finding suggested that KQ cotreatment with Cu(II) produced increased amounts of H2O 2, thus enhancing subsequent cell death due to necrosis. © 2011 by the authors.