Experimental study on intracellular antioxidant activity of water soluble polyphenols from tea and coffee

  AIM  To investigate possible protective and repair effects of water-soluble polyphenols in tea and coffee on oxidative damage at conventional drinking concentration.

  METHODS  Oxidative stress models of H₂O₂ injury of mainly human umbilical vein endothelial cells (HUVEC) and other cells were established. DCFH-DA probe test was used to detect the reactive oxygen species (ROS) level in cells and tetramethylazolidazole blue colorimetric test (MTT) was used to determine the cell viability.

  RESULTS  The three types of tea and two types of coffee tested all had anti-ROS generation and anti-cell oxidative damage ability in HUVEC cells and the activity increased with the increase of concentration. Green tea had the strongest antioxidant properties, followed by the two types of coffee and then black tea and dark tea. This intracellular antioxidant activity was repeated in gastric mucosa GES-1 and gastric cancer SGC7901 cells. None of the five polyphenolic beverages had the ability to repair oxidative damaged cells.

  CONCLUSION  The water-soluble antioxidant components of tea and coffee at conventional drinking concentration can effectively enter vascular endothelial cells and gastric mucosal epithelial cells. These water-soluble antioxidant components have the ability to clear ROS and resist cell oxidation, but they not have the ability to repair cells that have been oxidized.