The analysis of the constituents was performed on an Agilent HPLC (1260 infinity) equipped with a diode array detector (1260 variable wavelength detector) with an XBridge® C18 column (5 μm, 150 mm × 4.6 mm i.d., Shimadzu, JPN). The chromatographic separations were carried out on a mobile phase consisting of 0.1% acetic acid (A) and acetonitrile (B) using a gradient programmes of 5–5% (B) in 0–15 min, 5–20% (B) in 15–20 min, 20–40% (B) in 20–35 min and 40–50% (B) in 35–60 min at a flow rate of 1.0 mL/min and column temperature of 25 °C. The injection volume was 10 μL, and the UV detection wavelength was 351 nm.
The EXD extract (0.1 g) was placed in a volumetric flask with 10.0 mL of 95% methanol at 60 °C for 2 h, during which the mixture was subjected to ultra-sonication for 15 min twice. Authentic samples were prepared in methanol solution (1.0 mg/mL). All the samples were filtered through a 0.22 μm filter (Millipore) before they were injected into the HPLC. Peaks were confirmed using the UV absorption and retention times of the authentic samples.
The EXD extract (0.1 g) was placed in a volumetric flask with 10.0 mL of 95% methanol at 60 °C for 2 h, during which the mixture was subjected to ultra-sonication for 15 min twice. Authentic samples were prepared in methanol solution (1.0 mg/mL). All the samples were filtered through a 0.22 μm filter (Millipore) before they were injected into the HPLC. Peaks were confirmed using the UV absorption and retention times of the authentic samples.