Effect of deep eutectic solvent extraction on Auricularia auricula polysaccharide solubilization and antioxidant potential

This study was conducted to assess the potential of a green and eco-friendly technique: ultra-sound-assisted natural deep eutectic extraction (UAE-DES) for the preparation of Auricularia au-ricula polysaccharides (AAPs), and to evaluate the antioxidant capacity of the products. Firstly, the optimal parameters for AAPs by Box-Behnken using deionized water as the solvents, and the yield was 25.07% & PLUSMN; 0.43% at 50 & DEG;C, 70 mL/g of liquid-to-material ratio and 150 W of ultrasonic power. Next, the effects of five types of DES on the output of the AAPs under this parameter were investigated. DES (ethylene glycol-choline chloride, molar ratio of 2:1) containing 40% water in-creased the yield by 18.68%. The molecular weight of AAPs-UW (using deionized water as sol-vents) was 851.029 kDa, while the UAE-DES fractured AAPs-UD (using DES as solvents) into three polysaccharides, 811.895, 277.178 and 15.520 kDa, respectively. AAPs-UD showed signifi-cantly stronger ABTS+/OH & BULL;/DPPH & BULL; scavenging capacity than AAPs-UW. Compared with AAPs-UW, AAPs-UD treatment prolonged the maximum lifespan and the mean survival time of C. ele-gans at low concentration. In addition, qRT-PCR results indicated that AAPs-UD could up-regulate the expression levels of antioxidant related genes such as daf-16, sir-2.1 and sod-3 in the insulin and IGF-1 signaling pathway (>1.50, p < 0.05), and the expression of skn-1 in the target of ra-pamycin pathway (>1.70, p < 0.05).

Automated summary

This study evaluated the potential of ultra-sound-assisted natural deep eutectic extraction (UAE-DES) for the preparation of Auricularia auricula polysaccharides (AAPs) and examined their antioxidant capacity. Optimal parameters were determined using deionized water as the solvent, resulting in a 25.07% ± 0.43% yield at 50°C, 70 mL/g liquid-to-material ratio, and 150 W ultrasonic power. The yield of AAPs was increased by 18.68% using DES (ethylene glycol-choline chloride, molar ratio of 2:1) containing 40% water. AAPs-UD, prepared with DES as solvents, showed significantly stronger ABTS+/OH•/DPPH• scavenging capacity compared to AAPs-UW, and prolonged the lifespan of C. elegans. Furthermore, AAPs-UD up-regulated the expression of antioxidant-related genes in insulin and IGF-1 signaling pathway, as well as skn-1 in the target of rapamycin pathway.