5%, w/v). After 30 min, the absorbance was measured
at 765 nm, and the results were expressed as mg/L catechin equivalent. High-performance liquid chromatography (HPLC) analysis was used to quantify the presence of individual phenolic compounds. Prior to Gemcitabine the HPLC analysis, 1.5 mL of each sample was filtered through a cellulose membrane (diameter 0.2 μm). The equipment used in the analysis consisted of an LC-DAD Series 1100 liquid chromatographic system (Hewlett–Packard, Palo Alto, CA) with a diode array detector system. The chromatographic analyzes were a modification of the methods described by Lamuela-Raventós and Waterhouse (1994). A Zorbax SB C18 (250 × 4.6 mm), 5 m particle size, with a flow of 0.5 mL/min, was used for the stationary phase. After filtration on a 0.2 m Millipore membrane, five microliters of grape juice was injected into the HPLC system. The solvents used for the separation were as follows: solvent A (50 mM dihydrogen
ammonium phosphate adjusted to pH 2.6 with orthophosphoric acid), solvent B (20% of solvent A with 80% acetonitrile) and solvent C (0.2 M orthophosphoric acid adjusted with ammonia to pH 1.5). The gradient conditions were as follows: solvent A 100% (0–5 min), solvents A 96% and B 4% (5–15 min), solvents A 92% and B 8% (15–25 min), solvents B 8% and C 92% (25–45 min), solvents B 30% and C 70% (45–50 min), solvents B 40% and C 60% (50–55 min), solvents B 80% and C 20% (55–60 min) and solvent A 100% (60–65 min). Chromatograms were monitored at 204 nm, and identification was based on the retention time relative to authentic standards ((+)-catechin, (−)-epicatechin, Enzalutamide solubility dmso procyanidin B1, B2 and gallic acid). Quantification was performed Adenosine using the standards by establishing
calibration curves for each identified compound. Results are shown in mg/L. To determine cyanidin-3-glucoside, delphinidin-3-glucoside, peonidin-3-glucoside, malvidin-3-diglucoside and malvidin-3-glucoside, we used a mobile phase with solvents A (ultrapure water, formic acid, and acetonitrile) and B (ultrapure water, formic acid, and acetonitrile) in a constant flow of 0.8 mL/minute with a controlled temperature of 40 °C. The gradient conditions were as follows: solvents A 94% and B 6% (0 min), solvents A 70% and B 30% (0–15 min), solvents A 50% and B 50% (15–30 min), solvents A 40% and B 60% (30–35 min), solvents A 94% and B 6% (35–41 min). The peak was detected at 518 nm, and the amount of sample injected was 50 μL (OENO, 2003). To quantify the resveratrol compound, we used a mobile phase of ultrapure water and acetonitrile (75:25 vol/vol) (pH 3.0) with a constant flow of 1.0 mL/min for 20 min with a controlled temperature of 25 °C. The gradient conditions were as follows: solvents A 10% and B 90% (0 min), solvents A 85% and B 15% (0–23 min), solvents A 95% and B 5% (23–30 min), solvents A 10% and B 90% (30–35 min). The peak was detected at 385 nm, and the amount of sample injected was 20 μL (McMurtrey et al., 1994).