Metabolic profiling-based screening of potential hepatotoxic combinations in green tea components under non-specific...

Non-physiologically high concentrations of epigallocatechin-3-O-gallate (EGCG), a major green tea catechin, can cause hepatotoxicity. However, the actual cellular effects of EGCG itself remain unclear, because reactive oxygen species (ROS) are generated through auto-oxidation in vitro. Herein, the effect of EGCG on hepatocellular growth and viability was evaluated under ROS-free conditions created by antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) in the normal murine liver cell line NMuLi. Although EGCG at high concentrations (>20 μM) suppressed the ATP level as an indicator of cell growth and viability, this effect was eliminated by SOD/CAT. Under ROS-free conditions, physiologically relevant EGCG (<5 μM) did not affect the ATP level. A chemometric approach, metabolic profiling (MP) analysis of multiple green tea extracts, enabled the screening of compounds acting synergistically with EGCG (5 μM) to reduce ATP levels. These findings suggest the effectiveness of applying the MP method with SOD/CAT-treated cellular systems to determine compound combinations inducing potential hepatotoxicity of EGCG.