Antioxidant and Hypoglycemic Activity of Polysaccharides With Different Tissues From Rosa roxburghii f. eseiosa Ku

Rosa roxburghii f. eseiosa Ku, a thornless variety of Rosa roxburghii Tratt, remains underexplored regarding the tissue-specific functionality and structure-activity relationships of its polysaccharides. This study systematically investigated the composition and bioactivities of polysaccharides extracted from the fruit, root, stem, and thick stem of this variant. Using gradient ethanol precipitation (40%, 60%, and 80%), polysaccharides with distinct molecular weight (M w ) profiles were obtained. All isolates were identified as acidic heteropolysaccharides with complex and tissue-dependent monosaccharide compositions. Fractions precipitated with 60% and 80% ethanol exhibited lower M w s and significantly enhanced bioactivities, including potent radical scavenging capacity and α -glucosidase inhibition. Notably, RREK-R60, the crude polysaccharide obtained from the roots of Rosa roxburghii f. eseiosa Ku via 60% ethanol precipitation, exhibited a notable α -glucosidase inhibition rate of 92.91%. Structural analysis revealed tissue-specific traits, such as the unique presence of N-acetylglucosamine in fruit and root samples, along with elevated uronic acid, galactose, and arabinose content, which correlated strongly with bioactivity. These findings underscore the potential of Rosa roxburghii f. eseiosa Ku polysaccharides as functional food ingredients or anti-diabetic agents. Further in vivo studies and detailed structural elucidation are warranted to fully establish their structure-activity relationships. Graphical The graphical abstract comprises three sections. The left panel shows the distribution of different tissues of Rosa roxburghii f. eseiosa Ku. The middle illustrates the flowchart for the extraction and purification of crude polysaccharides. The right section presents Key Findings on Bioactive Polysaccharides from Rosa roxburghii f. eseiosa Ku. This figure summarizes the structure-activity relationships of polysaccharides from various tissues of the plant. Major findings include: 1) N-Acetylglucosamine content positively correlates with 2,2-diphenylpicrylhydrazyl radical scavenging activity; 2) Polysaccharides obtained with 60–80% ethanol exhibit superior antioxidant capacity, attributed to lower molecular weight and higher polyphenol content; 3) Higher galactose content in RREK-F60 and RREK-R60 enhances 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging; 4) RREK-R60 shows remarkable α-glucosidase inhibition (92.91%), likely due to its high arabinose, glucose, and xylose composition.