Purification of polysaccharides from Phellinus linteus by using an aqueous two-phase system and evaluation of the physicochemical and antioxidant properties of polysaccharides in vitro

Abstract

In this study, Phellinus linteus polysaccharides (PLPS) and proteins were simultaneously separated from P. linteus mycelia by using an aqueous two-phase system (ATPS) based on choline chloride ([Chol]Cl)/K₂HPO₄, and the physicochemical and antioxidant properties of PLPS after ATPS extraction were evaluated. Results demonstrated that the maximal extraction efficiencies of 68.53% ± 0.29% PLPS and 82.37% ± 0.41% proteins were obtained when the cholinium-based ATPS contained 68.9% K₂HPO₄, 20% [Chol]Cl, 10.0 mg mL⁻¹ crude water extract (1.0 mL), and distilled water (4.0 mL) at shaking time and temperature of 30 min and 21.2 °C, respectively. Compared with C-PLPS obtained using traditional ethanol precipitation and isolation protocols, PLPS had higher carbohydrate content (63.58% ± 1.12%), lower molecular weight (15.2 kDa, 80%), different monosaccharide compositions, and showed similar preliminary structural characterizations. Moreover, PLPS exhibited more evident scavenging effects on free radicals and in vitro antioxidant activities than C-PLPS. Therefore, the method of [Chol]Cl/K₂HPO₄ ATPS can be developed as an effective strategy for the separation/purification of highly bioactive polysaccharides.

Keywords:

• Antioxidant activity
• aqueous two-phase system
• choline chloride
• Phellinus linteus polysaccharides
• physicochemical properties
• separation

Additional information

Funding

This work was supported by the Major Public Welfare Projects in Henan Province [201300110200], the National Science Foundation of China [Grant No U1604176] and Program for Innovative Research Team (in Science and Technology) in University of Henan Province [Grant No 20IRTSTHN022].