Efficient extraction of flavonoids from Cercis chinensis bark using ultrasound-assisted deep eutectic solvents: Process optimization, characterization, kinetic studies, antioxidant and enzyme inhibition activities
Penghua Shu, Simin Liu, Na Wang, Shuxian Fan, Yu Meng, Xin Fan, Shoujie Guo, Sirong Peng, Yu Chen, Tingting Guo, Jiaqi He, Wenhao Zou, Xialan Wei, Lin Zhang, Jihong Huang
Abstract
This study presents an efficient and eco-friendly approach for extracting flavonoids from Cercis chinensis bark using ultrasound-assisted deep eutectic solvent (UAE-DES) extraction. Among 13 screened DES systems, L -proline-sorbitol (molar ratio 1:2, DES-9) exhibited the maximum extraction yield (51.2 mg/g), significantly outperforming conventional 60 % ethanol extraction. An optimal flavonoid yield of 87.6 mg/g was achieved through the optimization of key parameters (ultrasonic temperature, ultrasonic time and water content) using Response Surface Methodology, with the ideal conditions identified as 42 °C, 40 min and 8 % water. UPLC-Q-Exactive Orbitrap MS analysis revealed that C. chinensis bark flavonoids were mainly composed of quercetin, astragalin, kaempferol and afzelin. Scanning electron microscopy (SEM) showed that DES-9 induced severe cellular disruption, enhancing flavonoid release. Extraction kinetics followed a pseudo-first-order model, with a calculated apparent activation energy of 3.53 kJ/mol, indicating a diffusion-controlled process. The DES extract demonstrated superior antioxidant and enzyme inhibitory activities compared with the 60 % ethanol extract. Additionally, DES recovery via macroporous resin achieved an 87.23 % flavonoid recovery rate, with the solvent maintaining over 80 % efficiency after three reuse cycles. These findings underscore the UAE-DES method as a sustainable and effective strategy for valorizing C. chinensis bark into high-value natural medicinal products. • UAE-DES extraction for flavonoids from Cercis chinensis bark. • Optimal flavonoid yield of 87.6 mg/g achieved with UAE-DES. • DES induces cell disruption and diffusion-controlled kinetics. • 18 flavonoids were identified by UPLC-Q-Exactive Orbitrap MS. • DES recyclable with over 80 % efficiency after three cycles.