Extraction and UHPLC Analysis of Powdered Samples

The dry materials were ground to a fine powder. Approximately 50 mg of powder was extracted in 5 mL of methanol by ultrasonication at 50 °C for 50 min, followed by centrifugation. Samples were separated using ultrahigh-performance liquid chromatography (UHPLC) with an ACQUITYUPLCBEH-C18 (2.1 mm × 50 mm, 1.7 μm, Waters). In the solvent system, mobile phase A was 0.1% (v: v) formic acid, and mobile phase B was methyl-alcohol. The gradient conditions applied were as follows: 0~7 min, 25% ~ 40% B; 7~10 min, 40% ~ 50% B; 10~11 min, 50% ~ 40% B; 11~12 min, 40% ~ 25% B; 12~14 min, 25% B. The flow rate was set at 0.3 mL/min, and the injection volume was 1 μL.