Reactive oxygen species (ROS) such as hydrogen peroxide, superoxide anion, and hydroxyl radical
lead to damages of cellular molecules and are a cause of cancer. To find the anticancer compounds
that scavenge the ROS, we have screened the antioxidant effect against DPPH radical and H2O2 induced
oxidative stress from 39 flavonoids at 10μg/ml. (+)-Catechin and epicatechin at 10μg/ml were found
to scavenge DPPH radical and intracellular ROS. We also investigated whether two compounds may
show anticancer effect against cancer cells by MTT reduction assay. As a result, epicatechin showed
the strongest cytotoxicity to U937 cells among NCI-H460, HeLa, U937, and MCF-7 cells.

Keywords: Oxidative stress, Reactive oxygen species, Anticancer