Structural characterization and biological activities of a novel polysaccharide from Glehnia littoralis and its application in preparation of nano-silver

A novel polysaccharide (GLP) with a molecular weight of 1.37 × 105 Da was purified from the roots of G. littoralis. Using monosaccharide composition, methylation analysis, GC–MS, 1D and 2D NMR, the structure of GLP was determined to be a 1 → 4)-α-D-Glcp glycoside linkage, while the terminal group of 1→)-α-D-Glcp was bonded to the main chain via O-6. Then, GLP-NPs were prepared by nano-precipitation method, the particle size of GLP-NPs was 288.4 nm and PDI was 0.340. GLP-NPs-AgNPs were prepared using GLP-NPs as reducing agent. GLP-NPs-AgNPs were characterized by ultraviolet-visible spectrophotometer (UV–Vis), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM) and X-ray diffraction (XRD). The yield of GLP-NPs-AgNPs was 38.77%, the particle size was 12.5 nm and the chelation rate of silver nanoparticles with polysaccharides was 67.5%. GLP-NPs-AgNPs had better antioxidant and antibacterial activities than GLP and GLP-NPs. In the present work, a simple and eco-friendly approach for the synthesis of silver nanoparticles (AgNPs) using G. littoralis polysaccharides nanoparticles (GLP-NPs) as reducing agent.