Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem Epigallocatechin-3-O-gallate, the main green tea component, is toxic to Saccharomyces cerevisiae cells lacking the Fet3/Ftr1 Lavinia L. Ruta, Claudia V. Popa, Ioana Nicolau, Ileana C. Farcasanu ⁎ University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, Sos. Panduri 90-92, 050663 Bucharest, Romania ARTICLE INFO Keywords: Epigallocatechin-3-O-gallate Copper Saccharomyces cerevisiae FET3 FTR1 Chemogenomic screen Chemical compounds studied in this article: Epigallocatechin 3-O-gallate (PubChem CID: 65064) Epigallocatechin (PubChem CID: 72277) Epicatechin (PubChem CID: 72276) Gallic acid (PubChem CID: 370) Bathocuproine disulfonate (PubChem CID: 170300) Copper(II) chloride (PubChem CID: 24014) Copper(I) chloride (PubChem CID: 62652) ABSTRACT 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. 1. Introduction Green tea is one of the most consumed beverages in the world and its health benefits cover a wide range of chemo-protective actions at- tributed to its chemical constituents, which exhibit various biological and pharmacological properties (Butt, Ahmad, Sultan, Qayyum, & Naz, 2015; Cao, Han, Xiao, Qiao, & Han, 2016; Hayat, Iqbal, Malik, Bilal, & Mushtaq, 2015; Jacob, Khan, & Lee, 2017; Khan & Mukhtar, 2013; Reygaert, 2014; Singhal, Raj, Gupta, & Singh, 2017; Vuong, 2014; Xu, Xu, & Zheng, 2017). The main compounds responsible for the activities of green tea are the polyphenols known as flavanols, with epigalloca- techin-3-O-gallate (EGCG) being the most abundant (Hara, 2001). Nu- merous studies indicate that EGCG is a potent antioxidant and anti- inflammatory agent responsible for many of the biological actions of green tea associated with the prevention and/or treatment of chronic diseases, such as cancer, heart diseases, obesity, diabetes and neuro- degenerative diseases (Chikara et al., 2018; Eng, Thanikachalam, & Ramamurthy, 2018; Fujiki, Sueoka, Rawangkan, & Suganuma, 2017). In spite of the numerous health benefits, some studies focus on the potential toxicity of excessive consumption of green tea and especially of nutraceuticals containing EGCG, in both human and experimental animals (Dekant, Fujii, Shibata, Morita, & Shimotoyodome, 2017; Rasheed, Ahmed, Abdallah, & El-Sayeh, 2017). Studies concerning the beneficial role of green tea and its components are numerous, but re- ports on their toxicity are still scarce. In this study attempts were made to unravel the molecular aspects related to EGCG toxicity using a yeast- based chemogenomic screen of a Saccharomyces cerevisiae gene deletion library. Yeast chemogenomic approaches can be used to identify mo- lecular components indicative of a cell response upon exposure to various molecules, by testing the fitness of yeast deletion libraries, also known as Yeast KnockOut (YKO) collections (Hillenmeyer et al., 2008). By screening a collection of ∼4800 YKO mutants against EGCG ex- posure it was revealed that cells with no functional Fet3/Ftr1 complex exhibited poor growth in the presence of EGCG, a phenotype that was augmented by surplus copper. Copper is essential for life and a variety of enzymes require copper as a cofactor necessary for electron transfer reactions (De Freitas et al., 2003). Copper in excess is very toxic due to its ability to produce free radicals when cycling between oxidized Cu(II) https://doi.org/10.1016/j.foodchem.2018.06.029 Received 25 February 2018; Received in revised form 18 May 2018; Accepted 6 June 2018 ⁎ Corresponding author. E-mail addresses: lavinia.ruta@chimie.unibuc.ro (L.L. Ruta), valentina.popa@chimie.unibuc.ro (C.V. Popa), ioanaa.dumitru@g.unibuc.ro (I. Nicolau), ileana.farcasanu@chimie.unibuc.ro (I.C. Farcasanu). Food Chemistry 266 (2018) 292–298 Available online 07 June 2018 0308-8146/ © 2018 Published by Elsevier Ltd. T