New method for green extraction of ginsenosides based on mechanochemically-assisted extraction and deep eutectic solvents

Abstract

Ginsenosides are the main active ingredients in ginseng. Studies have shown that ginsenosides have anti-virus, anti-tumor, anti-aging, nootropic, cardiovascular diseases-protecting, and other pharmacological activities. Thus, the development and utilization of ginsenosides have persistently attracted much attention. At present, the extraction of ginsenosides is mainly based on organic solvents, and there are relatively few studies on their green extraction. In this study, different deep eutectic solvents(DESs) were synthesized by heating and stirring method, combined with an emerging technology, mechanochemically-assisted extraction(MCAE), to extract ginsenosides in a green way. Six parameters that might affect the extraction effect were optimized to determine the optimal conditions, and the method validation was conducted. The new established method was compared with a commonly used extraction method(ultrasound-assisted extraction using 70% ethanol) to evaluate its extraction efficiency. The results revealed that the optimal extraction conditions of DES-MCAE were that the volume ratio of DES3(choline chloride∶urea 1∶2) and water in the extraction solvent was 6∶4, and the liquid ratio and the linear vibration speed were 0.05 g·mL~(-1) and 4.0 m·s~(-1); the extraction was performed twice, 40 s each. With only 80 s extraction, the extraction rate of this method was 36.22% higher than that of ultrasoun-dassisted extraction using 70% ethanol. In this study, a DESs-based pretreatment method for ginsenosides was established and its rapid, green and efficient extraction was realized, which provided new ideas and methods for further research on green extraction of other active ingredients from Chinese medicine.