High-efficiency Ultrasound-assisted Deep Eutectic Solvent Extraction of Schisantherin A: Process Optimization and Bacteriostatic Activity

Abstract:

Ultrasound-assisted deep eutectic solvent extraction technology was employed to extract the active ingredient, Schisantherin A (SCA), from Schisandra sphenanthera. The optimal extraction solvent was determined, and the influences of water content, extraction temperature, liquid–solid ratio, sonication time, and sonication power on SCA extraction yield were investigated. Response surface methodology was adopted for optimization of the extraction process, and the optimized process was compared with extraction using conventional organic solvents. The results indicated that the optimal extracting agent was a combination of choline chloride and levulinic acid (molar ratio of 2:3), and the optimal process conditions for extraction were as follows: 20% water content of the solvent (volume fraction), 63 ℃ extraction temperature, 21:1 liquid-solid ratio (mL/g), 63 min sonication time, and 150 W sonication power. The SCA extraction yield under these conditions was 10.12 mg/g, which was close to the predicted value and demonstrated the effectiveness of the model in predicting the optimal process conditions for SCA extraction. In addition, the extraction yield was 1.98- and 3.30-fold that of the yields obtained by extraction using 80 vol% dimethyl sulfoxide and 95 vol% ethanol, respectively. Good bacteriostatic effects were exhibited when Escherichia coli was subjected to 24 hours of intervention with SCA at a mass concentration of 2.25~4.50 mg/mL. The results of this study can serve as reference for high-efficiency and green extraction of SCA and its development and application in bacteriostasis.