This study optimized the extraction, purification, and structural chemical characterization of polysaccharides from fruitless wolfberry bud tea (FWP), and evaluated their antioxidant activities against H2O2-induced oxidative damage in SH-SY5Y cells. Crude FWP was obtained by ultrasonic-assisted water extraction followed by ethanol precipitation. An orthogonal experiment was conducted to optimize decolorization using D301G macroporous resin, achieving a decolorization rate of 74%, a polysaccharide retention rate of 85%, and a protein removal rate of 61%. Two main purified polysaccharide fractions, FWP-1 (52.3 kDa) and FWP-2 (9.95 kDa), were isolated by DEAE-52 and Sephadex G-150 chromatography. Structural analysis revealed that FWP-1 was a neutral heteropolysaccharide rich in glucose and galactose, while FWP-2 was an acidic polysaccharide with a high content of galacturonic acid. In H2O2-induced SH-SY5Y cells, both polysaccharides significantly enhanced cell viability, increased superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels, reduced lactate dehydrogenase (LDH) leakage and malondialdehyde (MDA) content, scavenged excessive reactive oxygen species (ROS), and maintained mitochondrial membrane potential. FWP-2 exhibited stronger ROS-scavenging capacity than FWP-1. This study established reliable methods for the purification and characterization of FWP, and verified their potential as natural antioxidants against neuronal oxidative injury.
Li et al. (Sun,) studied this question.