Structural characterization, physicochemical property, and antioxidant activity of polysaccharide components from Eucommia ulmoides leaves

Abstract Background Eucommia ulmoides (E. ulmoides) leaves are identified as a new resource of medicine and food homology. In this study, the structural characterization, physicochemical properties, and antioxidant activity of E. ulmoides polysaccharides (EUP) were studied. Results Three components with different molecular weights of 1.51 × 105 Da (EUP1), 3.05 × 104 Da (EUP2) and 1.17 × 105 Da (EUP3) were purified from E. ulmoides leaves. They were composed of l -rhamnose (Rha), d -arabinose (Ara), d -mannose (Man), d-glucose (Glu) and d -galactose (Gal), while EUP2 also contained small amounts of d -xylose (Xyl). Three components all had typical polysaccharides absorption peaks, which may be polysaccharides with β configuration of pyranose structure, and amorphous structure of acid polysaccharides with good thermal stability below 270 ℃. However, the molecular weight, monosaccharide composition and apparent morphology of the three components were different, resulting in a stronger scavenging ability of EUP2 and EUP3 against DPPH and OH free radicals. Conclusion The results will provide a theoretical reference for developing EUP-related foods and drugs. Graphical Abstract