The physiochemical characteristics of Phragmites communis trin polysaccharides and in vitro anti-diabetic effects of their different fractions

This study isolated and purified two polysaccharide fractions, PTP-1 and PTP-2, from Phragmites communis Trin root via cellulase-assisted ultrasonication and DEAE chromatography, with purities of 90.56% and 91.35%, respectively. Structural characterization revealed that PTP-2 possessed a higher uronic acid content (9.45%) compared to PTP-1 (3.0%), along with a hyperbranched architecture and superior thermal stability. High-performance gel permeation chromatography (HPGPC) indicated that PTP-1 and PTP-2 had weight-average molecular weights of 55.8 kDa and 59.6 kDa, respectively, reflecting distinct structural features. In vitro assays demonstrated that PTP-2 exhibited potent α-glucosidase inhibition (IC 50 = 0.679 mg/mL) and significantly enhanced glucose uptake and glycogen synthesis in insulin-resistant HepG2 cells, attributable to its uronic acid-enriched structure. These findings highlight PTP-2 as a promising multi-target agent for diabetes management, underscoring the structure–activity relationship of plant polysaccharides.