2.5. Preparation of sample solutions

Volatile oil was obtained from ESF (200.2 g) by reflux condensation for 5 h, according to the Chinese Pharmacopeia 2020 (Committee, ²⁰²⁰). Volatile oil was dried over Na₂SO₄, centrifuged at 13,000 rpm for 10 min, and stored at 4°C until further analysis. Following the same procedure, all 15 components of ESF were acquired.

ESF (30.04 g) was weighed and 450 mL n‐hexane was added at the ratio of 1:15 (M/V). Under the condition of ultrasonic power of 250 W, ultrasonic extraction was carried out for 30 min. After vacuum filtration, the fatty oil was obtained by rotating evaporation in water bath (60°C) until no n‐hexane was emitted. Then, 4 mL of 0.6 mol/L potassium hydroxide solution, methanol, and n‐hexane were added, respectively. After the mixture was evenly mixed and bathed at 60°C for 30 min, 10 mL distilled water was added and stratified. The upper layer was dried with Na₂SO₄, centrifuged at 13,000 rpm for 10 min, and stored at 4°C for further analysis. Following the same procedure, all 15 components of ESF were acquired.

ESF (20.02 g) was randomly weighed, 30 mL of 70% methanol at a ratio of 1:15 (M/V) was added, stirred and mixed, ultrasonically extracted for 1 h, leached at room temperature, and centrifuged at 12,000 rpm for 10 min, in which the supernatant was the aqueous extract of ESF.