File S1 - Molecular Interactions between (−)-Epigallocatechin Gallate Analogs and Pancreatic Lipase

Figures S1–S4 and Table S1. Figure S1. RP-HPLC spectra of EGCG incubated for 0 or 2 h. EGCG of 1 mmol/L was dissolved in 100 mmol/L PBS (pH 7.4) at 37°C. EGCG was analyzed on an Agilent 1100 HPLC system (Agilent Technologies, Palo Alto, CA, USA) using the ZORBOX 300-SB C18 column. Eluant A (5% aqueous methanol with 0.2% acetic acid) and eluant B (95% aqueous methanol with 0.2% acetic acid) were used for this analysis. The elution was achieved by a linear gradient of 0–100% eluant B mixed with eluant A in 50 min at 1.0 mL/min. The column effluent was monitored at 280 nm. Figure S2. Activity of urea-treated PL and EGCG complexes. The concentrations of PL and EGCG were 5 µmol/L and 0.5–2 mmol/L, respectively, in the original solutions. The solutions were incubated in 100 mmol/L PBS (pH 7.4) at 37°C for 45 min. After that, urea solution was added, and the final concentrations of urea, PL, and EGCG were 2 mol/L, 2.5 µmol/L and 0.25–1 mmol/L, respectively. PL activity was measured after dialysis. In the figure, the number 100, 200, 300, and 400 denoted the [EGCG]/[PL] ratio and the capital U meant the mixture was treated by urea solution. The activities of PL alone (PL), PL with urea solution (PL+U), and PL-EGCG mixture without urea (number 100–400) were compared. Figure S3. Secondary structures of urea-treated PL and EGCG complexes. a, CD spectra of urea-treated PL and EGCG complexes. The concentrations of PL and EGCG were 5 µmol/L and 0.5–2 mmol/L, respectively, in the original solutions. The solutions were incubated in 100 mmol/L PBS (pH 7.4) at 37°C for 45 min. After that, urea solution was added, and the final concentrations of urea, PL, and EGCG were 2 mol/L, 2.5 µmol/L and 0.25–1 mmol/L, respectively. Before measurement, solutions were diluted 2.5-folds to meet the limit of detection. b, the contents of secondary structure of urea-treated PL and EGCG complexes. Figure S4. SDS-PAGE of PL-EGCG mixture. The concentrations of PL and EGCG were 2.5 µmol/L and 0.25–1 mmol/L, respectively. The solutions were incubated in 100 mmol/L PBS (pH 7.4) at 37°C for 45 min before measurement. The [EGCG]/[PL] ratios from panel 1 to 4 were 0, 100, 200, and 400, respectively. Table S1. Absorbance of PL-EGCG mixture at 500 nm (A500). The concentrations of PL and EGCG were 2.5 µmol/L and 0.25–1 mmol/L, respectively. Experiments were done in 100 mmol/L PBS (pH 7.4) at 37°C. The A500 of EGCG alone (1 mmol/L) and PL alone were compared. (DOC)