Purification, Structural Analysis and Bioactivity of Pueraria montana Polysaccharide

<i>Pueraria montana</i> is a medicinal and edible plant widely distributed in Asia. It has antipyretic, analgesic, and anti-inflammatory properties. In this study, a novel polysaccharide (PMPS-A₁) was obtained through purification, and its biological activity was investigated. Structural analysis revealed that PMPS-A₁ was composed of fructose and glucose, with a molecular weight of 12168 Da. The main chain structure was →1)-β-D-Fru<i>f</i>-(2→, →4)-α-D-Glc<i>p</i>-(1→, →4)-α-D-Glc<i>p</i>-(1→, and →4)-α-D-Glc<i>p</i>-(1→. The branched chain of α-D-Glc<i>p</i>-(1→3)-α-D-Glc<i>p</i>-(1→ and α-D-Glc<i>p</i>-(1→ connected to the <i>O</i>-3 and <i>O</i>-6 positions of residue →3,4)-α-D-Glc<i>p</i>-(1→ and →4,6)-α-D-Glcp-(1→, respectively. In vitro, PMPS-A₁ had a favorable scavenging ability of the hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and downregulated the expression of interleukin-6 and nitric oxide in lipopolysaccharide-induced RAW264.7 macrophages. In addition, the Caenorhabditis model assay demonstrated that PMPS-A₁ decreased the buildup of lipofuscin and reactive oxygen species. Overall, these results enhance our knowledge of the chemical composition and bioactivity of a <i>Pueraria montana</i> polysaccharide and point to the potential use of PMPS-A₁ for antioxidant and anti-aging qualities, providing a theoretical basis for the medicinal and edible application of <i>Pueraria montana</i> polysaccharide.