Effect of green tea and its polyphenols on mouse liver.

Increased consumption of green tea (GT) without enough scientific data has raised safety concerns. Epigallocatechin 3-gallate (EGCG) is the most prominent polyphenol of GT that has antioxidant activity. However, higher doses of EGCG have been shown to cause liver injury. This study was initiated to determine the effect of GT extracts in a mouse model. We also investigated the effects of EGCG in normal and health-compromised mice. Different doses of GT fractions and EGCG were administered for 5 days to mice. Also, a single dose of lipopolysaccharide (LPS) was combined with EGCG in order to investigate its effect in the presence of fever. Plasma ALT and ALP levels were determined along with liver histopathology. Combining a single high IG dose of EGCG with a single IP dose of LPS initiated liver injury. Furthermore, repeated administration of high IG doses of EGCG showed mild liver injury, but it was augmented under febrile conditions induced by LPS. This study confirms the safety of reasonable consumption of GT over a short term. However, it highlights a caution that high doses of EGCG can lead to mild liver injury, and this may be markedly enhanced under febrile conditions.