150 mm column

Crushed grape powder (including pericarp, seed, flesh, and grape stem) (Zero Co. Ltd., Chiba, Japan) was dissolved in 70% ethanol, macerated for 7 days, and centrifuged at 3000 rpm for 20 min. The supernatant was filtered through a 0.22 μm membrane and completely dried. The resulting grape extract was dissolved in DMSO and stored at –80 °C. Resveratrol (Wako, Osaka, Japan) was also dissolved in DMSO at 100 mM and stored at −80 °C. A UPLC system (UPLC–SYNAPT G2-S HDMS) from Waters Co. (MA, USA) was used to roughly calculate the Resveratrol content in the grape extract (Figure S3). HPLC separation was achieved on a 2.1 × 150 mm column (Waters Co., MA, USA). The mobile phases consisted of (A) water and (B) methanol. The separation was carried out at room temperature with a 0.2 mL/min flow rate, under the following conditions: 0–30 min, 0–50% B, 30–50 min, 50–95 % B, 50–55 min, 95 % B isocratic, 55–60 min, 100–0% B, followed by a 5 min re-equilibration time of the column. Calculated by comparing the peak area at the same position, the grape extract contained 7% Resveratrol, so the concentration of Resveratrol in 50 μg/mL (100 μg/ml) grape extract was determined to be about 15 μM (30 μM).

2.1 × 150 mm column (Waters, Milford, MA, USA) on an Acquity UPLC (Waters) equipped with a Waters temperature control module and a Waters Acquity fluorescence detector was used. Solvent A was 50 mm formic acid adjusted to pH 4.4 with ammonia solution. Solvent B was acetonitrile. The column temperature was set to 40 °C. The 30‐min method was used with a linear gradient of 30–47% with buffer A at 0.56 mL·min⁻¹ flow rate for 23 min followed by 47–70% A and finally reverting back to 30% A to complete the run method. Samples were injected in 70% acetonitrile. Fluorescence was measured at 420 nm with excitation at 330 nm. The system was calibrated using an external standard of hydrolysed and 2AB‐labelled glucose oligomers to create a dextran ladder, as described previously (Royle et al., 2006).