Effect of green tea extract on reactive oxygen species produced by neutrophils from cancer patients.

BACKGROUND/AIM Oxidative stress in cancer patients has been demonstrated to be partly mediated by neutrophils. Although it is reported that natural antioxidants, such as green tea extract, reduce oxidative stress, there is limited evidence of their effects in cancer patients. This study aimed to determine the effect of green tea extract on reactive oxygen species produced by neutrophils from cancer patients. MATERIALS AND METHODS Peripheral blood samples were obtained from eighteen patients with advanced cancer. Green tea extract was added to the blood samples with luminol on Mebiol gel, and luminol-dependent chemiluminescence was measured to monitor the production of reactive oxygen species from migrated neutrophils into the gel, at 37°C. RESULTS Luminol-dependent chemiluminescence was significantly down-regulated in the presence of green tea extract in a concentration-dependent manner. CONCLUSION These results indicate the antioxidant effect of green tea extract on reactive oxygen species produced by neutrophils, which may be effective in reducing oxidative stress in cancer patients.