Extraction process optimization, purification and anti-aging activity investigation of Polygonatum kingianum polysaccharides

This study aimed to optimize the extraction process of Polygonatum kingianum polysaccharide (PKP), purify it to obtain the component PKP-1, analyze its chemical composition, and evaluate its anti-aging activity based on the Caenorhabditis elegans (C. elegans) model. Single-factor and orthogonal tests determined the optimal extraction conditions as follows: extraction time 2 h, liquid-to-material ratio 10∶1 mL·g^-1, and 3 extraction cycles. Subsequently, PKP was purified through ethanol precipitation, decolorization, deproteinization, dialysis, and DEAE-52 cellulose column chromatography, yielding the major fraction PKP-1. Analysis using the phenol-sulfuric acid method, BCA assay, sulfuric acid-carbazole method, Fourier transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC-MS) revealed that PKP-1 had a total sugar content of 86.36% ± 3.16%, contained no detectable protein or uronic acid, and its monosaccharides were primarily composed of fructose, glucose, and arabinose. Anti-aging activity assays in the C. elegans model demonstrated that PKP-1 significantly enhanced the worms' stress resistance, reduced the accumulation of reactive oxygen species (ROS) and lipofuscin, and effectively prolonged their lifespan. The results demonstrate that the optimized extraction process is efficient and feasible, and the purified PKP-1 exhibits high purity, is primarily composed of fructose, glucose, and arabinose, and possesses significant anti-aging bioactivity.