Catechin cat

CO₂ gas was supplied by Air Liquide (Fleury-les-Aubrais, France). Acetonitrile (ACN) and methanol (MeOH) were used for the mobile phase. Ethanol (EtOH) was used as the extraction solvent and sample diluent. All solvents were supplied by VWR (Fontenay-sous-Bois, France). Formic acid (FA) added to the mobile phase was obtained from Sigma-Aldrich (Merck, Semoy, France). Ultra-pure water (H₂O) was purified with a Milli-Q system from Sigma-Aldrich, St. Louis, MO, USA, with a resistance higher than 18 MW. Ethylenediaminetetraacetic acid (EDTA) and ascorbic acid (AA) used as stabilizing agents were supplied by Sigma-Aldrich.
The standards used to identify and/or quantify green tea target compounds (Figure 1) such as (−)-Epicatechin gallate (ECG), (−) Epigallocatechin (EGC), and (−)-Epicatechin (EC) were supplied by Extrasynthese (Genay, France). (−)-Epigallocatechin gallate (EGCG), (+)-Gallocatechin (GC), and (+)-Catechin (Cat) were acquired from Sigma-Aldrich. And finally, caffeine (Caff) was supplied by Thermo-Fisher Scientific (Artenay, France).

Minimum essential medium (MEM) and sodium pyruvate were purchased from Corning Cellgro (Manassas, VA, USA). Fetal bovine serum (FBS), penicillin–streptomycin (100×), and 0.25% trypsin-EDTA were obtained from Gibco Life Technologies (Grand Island, NY, USA). Pure phytochemicals (purity ≥ 96%) including theobromine (TH), protocatechuic acid (PCA), procyanidin B2 (PB2), epicatechin (EPI), and catechin (CAT) were purchased from Sigma-Aldrich (St. Louis, MO, USA) and Extrasynthese (Genay, France). Recombinant human FGF21 and PD173074 were obtained from R&D Systems (Minneapolis, MN, USA) and AdoQ Bioscience (Irvine, CA, USA), respectively.