Development of sample preparation method for eleutheroside B and E analysis in Acanthopanax senticosus by ionic liquids-ultrasound based extraction and high-performance liquid chromatography detection

An ionic liquids-based ultrasonic-assisted extraction (ILUAE) method was successfully developed for extracting eleutheroside B and E from Radix Acanthopanax senticosus. Thirteen 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were investigated and 1-butyl-3-methylimidazolium bromide ([C4mim]Br) solution was selected as the solvent. The conditions for ILUAE, including the ionic liquid concentration, soaking time, ultrasonic power, ultrasonic time, solid–liquid ratio and number of extraction cycles, were optimized. With the proposed method, the energy consumption time was reduced to 30 min, whereas conventional method requires about 4 h. The proposed method had good recovery (97.96–103.39%) and reproducibility (RSD, n = 5; 3.3% for eleutheroside B, 4.6% for eleutheroside E). ILUAE was an efficient, rapid and simple sample preparation technique that showed high reproducibility and was environmental friendly.