Simultaneous extraction of Saponin and Polysaccharide from Acanthopanax senticosus fruits with three-component Deep eutectic solvent and the extraction mechanism analysis

Abstract

As the deep eutectic solvent extraction has the advantages of excellent dissolving capability, high extraction efficiency and selectivity, a three-component deep eutectic solvent (3c-DES) was prepared with betaine, triethanolamine and MgCl2·6H2O (betaine: triethanolamine: MgCl2·6H2O = 1: 4: 0.08, molar ratio), and was used for simultaneous extraction of Acanthopanax polysaccharide and saponin from Acanthopanax senticosus fruits.Response surface methodology (RSM) was employed to optimize the saponin extraction factors. Under the optimum condition that material-liquid (AS powder to 3c-DES) mass ratio was 1:25 g/g, water content was 29 %, extraction temperature was 49 °C, extraction time was 3.5 h, the yield of saponin and polysaccharide were 1.04 and 3.40 wt%, respectively. The effect order on saponin is temperature > time > material-liquid ratio > water content. A quadratic polynomial parameter mathematical model was established to predict the experimental results. Molecular dynamics combined with density functional theory was used to analysis the mechanism of polysaccharide and saponin extraction that the main driving force is strong hydrogen bonding. The hydrogen bonds among deep eutectic solvent and polysaccharides and saponins is between 3.101 Å and 1.817 Å. The deep eutectic solvent could effectively simultaneously extract the saponins and polysaccharides of Acanthopanax senticosus fruits.