Epigallocatechin-3-O-gallate, the main green tea component, is toxic to Saccharomyces cerevisiae cells lacking the Fet3/Ftr1

Epigallocatechin-3-O-gallate (EGCG), the main green tea component, is intensively studied for its anti-oxidant, anti-inflammatory, anti-microbial and anti-cancer effects. In the present study, a screen on a Saccharomyces cerevisiae gene deletion library was performed to identify conditions under which EGCG had deleterious rather than beneficial effects. Two genes were identified whose deletion resulted in sensitivity to EGCG: FET3 and FTR1, encoding the components of the Fet3/Ftr1 high-affinity iron uptake system, also involved in Cu(I)/Cu(II) balance on the surface of yeast cells. The presence of EGCG in the growth medium induced the production of Cu(I), with deleterious effects on fet3Δ and ftr1Δ cells. Additionally, when combined, physiological surpluses of Cu(II) and EGCG acted in synergy not only against fet3Δ and ftr1Δ, but also against wild type cells, by generating surplus Cu(I) in the growth medium. The results imply that caution should be taken when combining EGCG-rich beverages/nutraceuticals with copper-rich foods.