Microwave-assisted extraction optimization of Hedysarum polybotys polysaccharide and study of their electrochemical fingerprint characteristics

Abstract

This study investigated the optimization of microwave-assisted extraction (MAE) and electrochemical fingerprinting of Hedysarum polybotys polysaccharides (HPS). Response surface methodology revealed optimal MAE conditions: 68°C, 420 W, 22 min, and 28 mL/g liquid-to-solid ratio, achieving a 6.38 % yield. HPS exhibited strong antioxidant activities, with 63.5 % DPPH scavenging at 2 mg/mL. Chemical analysis showed 15.2 % uronic acid content and a diverse monosaccharide profile dominated by glucose (38.5 %) and galactose (24.7 %). Cyclic voltammetry revealed a quasi-reversible redox couple (Epa = +0.28 V, Epc = +0.12 V vs. Ag/AgCl at 50 mV/s), while differential pulse voltammetry identified three distinct peaks (+0.14 V, +0.31 V, +0.52 V). The + 0.31 V peak strongly correlated with total sugar content (r = 0.92), and the + 0.52 V peak moderately correlated with uronic acid content (r = 0.68). Compared to conventional methods, MAE demonstrated superior efficiency, reducing extraction time from 3 h to 22 min and improving yield by 54.9 % over hot water extraction. This study establishes MAE as an effective technique for HPS extraction and introduces electrochemical fingerprinting as a promising tool for rapid polysaccharide characterization, opening new avenues for quality control and bioactivity assessment.