Trolox

HPLC grade acetonitrile (MeCN), methanol (MeOH), ethanol (EtOH), dimethylsulfoxide (DMSO), hydrochloric acid (HCl), and filter paper (110 mm pore size) were obtained from VWR International GmbH (Ismaning, Germany), and ultra-pure water (18MΩ.cm⁻¹) from a Millipore S.A.S. Milli-Q Academic system (18,2 MΩ cm⁻¹, Molsheim, France); 2,4,6-Tri(2-pyridyl)-s-triazine (TPTZ), potassium phosphate monobasic (KH₂PO₄), potassium phosphate dibasic (K₂HPO₄), ammonium acetate (NH₄AcO), iron(III) chloride (FeCl₃), hydrogen peroxide (30%) were from Merck KGaA (Darmstadt, Germany). Yeast extract peptone and MEM non-essential amino acid solution were obtained from Sigma-Aldrich (Taufkirchen, Germany) and collagen G from Biochrom AG (Berlin, Germany). Trolox was from Enzo Life Sciences GmbH (Lörrach, Germany), 2′,7′-dichlorodihydrofluorescein diacetate (H₂DCF-DA) and LB Broth Base were from Thermo Fisher (Waltham, MA, USA). DMEM medium was from PAN-Biotech GmbH (Aidenbach, Germany); MEM medium was from PromoCell (Heidelberg, Germany) and HEPES from AppliChem GmbH (Darmstadt, Germany). Fetal calf serum (FCS) was purchased from PAA Laboratories GmbH (Pasching, Austria) and l-glutamine, agar, and glucose were obtained from Carl Roth (Karlsruhe, Germany). Iceberg lettuce and cucumber were bought at a local supermarket and immediately used.

Three kinds of pure green tea (tea bags), the first two were popular Korean based brands and the third one, a well known international brand. First green tea was iced green tea (emart.kr), the second is Boseong green tea and the third one is Lipton green tea. These were purchased from a local supermarket in Seoul, Korea. Millipore water was used for all experiments. Standards of total phenolic acids (gallic acid) were procured from MP Biomedicals, LLC, Illkirch, France and of flavanoids (rutin hydrate) from abcam Biochemicals, Cambridge Science Park Cambridge CB4 0FL UK. Trolox was purchased from Enzo Life sciences Inc., Farmingdale, NY. 2,2-dyphenyl-1-picrylhydrazyl (DPPH) was obtained from Sigma Aldrich Company, St Louis, MO 63103, USA. The Folin- Ciocalteu’s phenol reagent and aluminium chloride (AlCl3) were from MP Biomedicals, LLC, BP 50067 Illkirch, France. All other solvents and chemicals were of analytical grade.