Green tea polyphenols have been identified as molecules responsible for the beneficial effects showed by the green tea against oxidative stress and cancer risk. We investigated the effects of green tea polyphenol extracts (GTPs) on oxidative stress and cell invasiveness in human gastric MKN-28 cancer cells. The pre-treatment with 10–4 M catechin equivalents of GTPs exerts a protective effect on xanthine-xanthine oxidase induced cell cytotoxicity, thus confirming the anti-oxidant properties of GTPs. The effect of GTPs was also extended on the cell migration and invasive ability induced by TNF-alpha or LPS. Results demonstrated that GTPs exposure (10–6 M) prevents the increase in cell invasiveness induced by the inflammatory agents. In addition, the treatment with GTPs prevented the TNF-alpha or LPS induced Matrix Metalloproteinases (MMP)-9/2 up-regulation. Our results demonstrated that GTPs reduced the oxidative stress and the invasive potential of gastric MKN-28 cancer cells thus confirming the protective role of these polyphenols against the metastatic process in gastric cancer
