Ultrasound-enzyme-assisted aqueous two-phase extraction, structural characterization and bioactivities of Coptis chinensis polysaccharides

Ultrasound-enzyme-assisted aqueous two-phase extraction (UEAATPE) was employed to simultaneously extract various polysaccharides from Coptis chinensis using an ethanol/(NH 4 ) 2 SO 4 biphasic solvent system. The optimization of UEAATPE was carried out through response surface analysis, informed by single-factor experiments. The optimal parameters identified were as follows: ultrasonic power of 210 W, ultrasonic duration of 5 min, compound enzyme concentration of 6.0 g/hg (ratio of enzyme to raw materials), pH 4.0, with aqueous two-phase system composition consisting of 24.0 g/hg ethanol and 19.0 g/hg (NH 4 ) 2 SO 4 in the total extraction system. The extraction lasted 2.1 h at a temperature of 51 °C, with a liquid-to-material ratio of 34:1 (g/g). The yields of polysaccharides from the upper phase (PTP) and lower phase (PBP) were found to be 1.269% and 4.695%, respectively. Compared to other methods, UEAATPE considerably enhanced yield due to a synergistic effect and enabled the extraction of distinct polysaccharides. While PTP and PBP showed similarities in IR characteristics and monosaccharide composition, they differed in molecular weight distribution, molar ratios of monosaccharide composition and surface morphology. Both polysaccharides exhibited notable immunomodulatory and antioxidant properties. These findings suggest that UEAATPE is a promising method for extracting and purifying various plant polysaccharides. • Extraction of various polysaccharides from Coptis chinensis by UEAATPE was developed. • The combination of multiple techniques significantly improved the extraction yield. • Structure and bioactivities of polysaccharides from both phases were analysed. • Two polysaccharides exhibited different structural characteristics.