Suppression of adhesion and invasion of hepatoma cells in culture by tea compounds through antioxidative activity

To determine the actions of tea components on the invasion of a rat ascites hepatoma cell line of AH109A and to understand their modes of action, the cancer cells were co-cultured with a rat mesentery-derived mesothelial cell monolayer in the presence of tea components. The synergistic effects of (−)-epicatechin (EC) with (−)-epigallocatechin gallate (EGCG) on AH109A invasion were demonstrated. Further study showed that 10 μM of EGCG or theaflavins, or 2.5 μM of ethylenediaminetetra-acetic (EDTA) entirely abolished the increase in AH109A adhesion and invasion stimulated by reactive oxygen species (ROS) from the hypoxanthine–xanthine oxidase system. Our results suggest that OH−- and other ROS-scavenging activity of EGCG and theaflavins may be responsible for the inhibition of OH−- and related ROS-potentiated AH109A adhesion and invasion to the cultured rat mesothelial cell monolayer.