Chromatographic system

HPLC chromatography was carried out using a chromatographic system (Agilent Technologies, Santa Clara, CA, USA) consisting of a quaternary pump, thermostated column compartment, a diode array detector (VWDG 1314A), manual injector (Rheodyne model 7725i) with 20 μL sample loop, and a degasser (g1379A) all the 1100 series. For all experiments, Column ZORBAXSB- Phenyl (150 mm × 4.6 mm i.d.) was used. For analyses of I, mobile phase A was a methanol/water mixture (ϕr = 1:99) and phase B was acetonitrile. In the analysis of isomers, the isocratic gradient A/B (ϕr = 1:1) at the flow rate of 0.6 mL min⁻¹ at 22 °C and detection at 236 nm was used. The injection volume was 20 μL. For analyses of II, mobile phase A was a methanol/water mixture (ϕr = 1:99) and phase B was methanol. In the analysis of isomers, the isocratic gradient A/B (ϕr = 37:13) at the flow rate of 0.6 mL min⁻¹ at 22 °C and detection at 236 nm was used. The injection volume was 20 μL.

Chromatographic conditions: Chromatographic system: Agilent Technologies; chromatographic column: Agilent 5 TC-C18(2), 250 mm × 4.6 mm, 5 μm; flow rate: 1 mL/min; column temperature: 25 °C; injection volume: 10 μL; mobile phase: 0.3% acetic acid (A)-methanol (B) (0–22 min: 32% B, 22–23 min: 32–37% B, 23–36 min: 37% B, 36–37 min: 37–45% B, 37–46 min: 45% B, 46–47 min: 45–60% B, 47–60 min: 60–80% B); UV absorption of eriodictyol and eriodicty-7-O-glucoside was monitored at 284 nm, while monitoring of luteolin and luteolin-7-O-glucoside was at 350 nm..
Preparation of mixed control solution (S1): A mixed solution containing eriodictyol-7-O-glucoside (0.348 mg/mL), eriodictyol (0.200 mg/mL), luteolin-7-O glucoside (0.270 mg/mL), and luteolin (0.156 mg/mL) in methanol was prepared as the control.
Preparation of test solution (S2): Dried MJGT was pulverized and passed through a 40-mesh sieve. A total of 1.7 g of MJGT was precisely weighed and placed in a 250-mL distillation flask. Then, 70% ethanol was added to the flask, which was securely stoppered and weighed. The contents of the flask were subjected to heat reflux extraction for 60 min and cooled to room temperature. Then, 70% ethanol was added to the flask to make up for the lost weight, and the contents of the flask were filtered through a 0.22-μm organic filtration membrane to obtain the test solution.

HPLC chromatography was carried out using a chromatographic system (Agilent Technologies, Santa Clara, CA, USA) consisting of a quaternary pump (G 1311A), variable wavelength detector VWD G 1314A), manual injector (Rheodyne model 7725i) with 20 μL sample loop, and a degasser (g1379A) all the 1100 series. For analyses of compounds 1 and 2, column ZORBAX SB-Phenyl (150 mm × 4.6 mm i.d), mobile phase A 0.1% HCOOH (formic acid), mobile phase B 55% CH₃CN (acetonitrile), and 0.1% HCOOH, at the flow rate of 1 mL min⁻¹ and detection at 390 nm, was used. For analyses of compounds 3 and 4, column Lichrosphere 100 RP-18e (250 mm × 4.0 mm i.d), mobile phase A water, mobile phase B CH₃CN with the gradient 0,0 min. 55% CH₃CN and 11 min. 99% CH₃CN, at the flow rate of 1 mL min⁻¹ and detection at 390 nm, was used.