[Differences of polysaccharides in Hedysari Radix before and after honey processing]

This study aims to reveal the differences of polysaccharides in Hedysari Radix before and after honey processing. After separation and purification of Hedysari Radix polysaccharides(HPS) and honey-fried Hedysari Radix polysaccharides(H-HPS) by gradient elution, UV spectrophotometry was employed to determine the content of polysaccharides and uronic acids in different eluate fractions. The molecular weights of different eluate fractions were determined by high-performance gel permeation chromatography(HPGFC). Ion chromatography(IC) was employed to detect the monosaccharide composition and content differences among eluate fractions. The results displayed that the gradient elution of HPS and H-HPS yielded three distinct fractions, which were the fractions from elution with distilled water, 0.1 mol·L~(-1) NaCl, and 0.3 mol·L~(-1) NaCl, respectively. The total polysaccharide and uronic acid content in all eluate fractions of H-HPS were higher than those in the eluate fractions of HPS. Both HPS and H-HPS showed a distribution pattern where the distilled water eluate had the highest total polysaccharide and uronic acid content, followed by the 0.1 mol·L~(-1) NaCl eluate, and the 0.3 mol·L~(-1) NaCl eluate had the lowest. The molecular weight distribution profiles demonstrated that all elution fractions were uniform in structure. After honey processing, the peak symmetry was improved and the structural uniformity was enhanced. During elution under different ionic strengths, with the increase in ionic strength, the polysaccharide distribution tended to be more uniform, with increased molecular size and enhanced stability. In addition, honey processing led to a reduction in the overall molecular weight and a narrower distribution range of polysaccharides, rendering them more stable under the same elution conditions. In particular, the fraction eluted with 0.3 mol·L~(-1) NaCl exhibited high uniformity and a large molecular size. In terms of monosaccharide composition, honey processing induced characteristic changes across fractions. Specifically, the distilled water eluate contained the fewest monosaccharides; the elution with 0.1 mol·L~(-1)NaCl introduced fucose while increasing glucose, xylose, and mannose; the elution with 0.3 mol·L~(-1) NaCl doubled galacturonic acid content, making it a unique component, while glucuronic acid completely disappeared. The study found that honey processing, through reactions such as hydrolysis and decarboxylation, significantly increases polysaccharide and uronic acid content while restructuring their molecular architecture. This provides a theoretical foundation for elucidating the effect-enhancing mechanism of honey processing for Hedysari Radix and for evaluating and developing the polysaccharides in Hedysari Radix and its processed products.