Extraction and properties of Cyclocarya paliurus leaf polysaccharide and its phosphorylated derivatives

Chemical modification provides an important idea for advancing and harnessing plant polysaccharides. It is well known that Cyclocarya paliurus (Batalin) Iljinskaja (C. paliurus), is an important industrial crop resource, and polysaccharide stands as one of the compounds displaying a wide range of bioactivities within the leaves of C. paliurus. The study found that C. paliurus polysaccharides (CPP) were subjected to phosphate modification to obtain two phosphorylated polysaccharides (P-CPPL and P-CPPH) with degrees of substitution (DS) of 0.10 and 0.18, correspondingly. The findings indicated that the phosphorylation changed the chemical composition, relative molecular weight, molar ratio of monosaccharide composition and microstructure of CPP, thus changing the thermal stability and bioactivities of CPP. In vitro bioassay results demonstrated that CPP and its phosphorylated derivatives showed antibacterial activity at high concentrations. In addition, phosphorylation changes the water solubility and spatial configuration of CPP, so that P-CPPL and P-CPPH can bind or interact with enzymes more effectively, thus improving the α-glucosidase inhibitory activity in vitro. In vitro cell experiment results demonstrate that CPP and its phosphorylated derivatives can protect IEC-6 cells from oxidative damage by restoring mitochondrial membrane potential levels and modulating the expression and activation of Caspase-3. In summary, phosphorylation provided an essential way of changing the chemical properties of polysaccharides and enhancing their functionalities.