Ultrasound-assisted deep eutectic solvent extraction of polysaccharides from Cercis chinensis bark: Optimization, kinetics and antioxidant activities
Penghua Shu, Na Wang, Meng Yu, Shuxian Fan, Simin Liu, Xin Fan, Di Hu, Hao Yin, Huiying Wang, Xin Wang, Mengjiao Wu, Feng Yu, Xialan Wei, Lin Zhang, Jihong Huang
Abstract
This study pioneers a green, efficient ultrasound-assisted extraction (UAE) technique using a deep eutectic solvent (DES) to isolate polysaccharides from Cercis chinensis bark, overcoming limitations of conventional methods. Through systematic screening of 15 DES systems, DES-11 (L-proline:ethylene glycol, 1:2 M ratio) was identified as optimal, achieving a polysaccharide yield of 64.7 mg/g—3.7-fold higher than water extraction. Extraction conditions were optimized via response surface methodology (RSM) to 39 % water content, 45 °C, 28 min, solid-liquid ratio 1:40 g/mL, and 240 W ultrasonic power. SEM analysis confirmed that DES-11 disrupts plant cell walls, enhancing mass transfer. Kinetic studies revealed the process follows pseudo-first-order kinetics (R 2 > 0.90) and is primarily controlled by intraparticle diffusion, with an apparent activation energy of 10.28 kJ·mol −1 . The DES-11 extracted polysaccharides exhibited moderate antioxidant activity, with IC 50 values of 0.54 mg/mL (DPPH), 0.24 mg/mL (ABTS) and 0.62 mg/mL (OH), suggesting potential as natural food preservatives. DES recyclability was validated over five cycles, retaining > 78 % efficiency. This work establishes DES-UAE as a sustainable strategy for high-yield polysaccharide extraction, with mechanistic insights into kinetics and diffusion control.