Enhancing effect of zinc on hepatoprotectivity of epigallocatechin gallate in isolated rat hepatocytes.

The influence of metal ions (Fe2+, Cu2+, Zn2+) on the hepatoprotective activity of epigallocatechin gallate (EGCG) against hepatotoxin-induced cell injury was investigated. Primary cultures of rat hepatocytes were treated with a well-known hepatotoxin, bromobenzene (BB), in the presence of EGCG only or EGCG plus each metal ion. After 24 h, 0.02 mM EGCG did not show protective activity on the cultured hepatocytes. In contrast, the hepatocytes were protected against BB in the presence of 0.02 mM EGCG and 0.02 mM zinc. The addition of only zinc could not protect hepatocytes against BB. These results suggest that the formation of the zinc-EGCG complex is very important in the enhancement of the hepatoprotective activity of EGCG. The complexation of EGCG with zinc was confirmed by UV-VIS absorption spectroscopy.