Evaluation of Tea Extract as an Inhibitor of Oxidative Stress in Prostate Cells

Oxidative DNA damage is caused by free radicals eroding the cell membrane and directly attacking DNA molecules in the cell. This DNA damage plays an important role in the development of cancer. Antioxidants remove free radical intermediates, thereby preventing cell membrane erosion and subsequent DNA damage. Tea leaves are rich in antioxidants, and studies conducted on green tea have reported numerous health benefits; however, those studies left out other types of tea. We evaluated the ability of various tea extracts to protect prostate cells from hydrogen peroxide induced oxidative damage. Cells were treated with black, oolong, green, and white tea extracts and then exposed to hydrogen peroxide for two days, followed by a quantification of viable cells using an MTS assay. Because treatment with white tea extract yielded the greatest cell viability, we hypothesized that an abundant antioxidant in white tea, epigallocatechin-3-gallate (EGCG), might also protect cells from oxidative stress. We found that, indeed, pre-treatment of prostate cells with 50 mg/mL EGCG led to a significant increase in cell viability when compared to the control group (fold change of 2.90), based on MTS assay absorbance. These data suggest that antioxidants in white tea extract, including EGCG, protect prostate cells from oxidative stress in culture, which is suggestive of the health benefits of white tea.