Discrimination of Polygonatum Species via Polysaccharide Fingerprinting: Integrating Their Chemometrics, Antioxidant Activity, and Potential as Functional Foods

<i>Polygonati</i> Rhizoma, a renowned edible homologous material, encompasses an array of widely distributed species. Despite their morphological and medicinal similarities, their overlapping distribution and evolving varieties present challenges for their classification and identification. This study provides a comprehensive characterization of the physicochemical and antioxidant properties of polysaccharides extracted from three common species: <i>P. sibiricum</i>, <i>P. cyrtonema</i>, and <i>P. kingianum</i>. An analysis of their monosaccharide composition reveals distinct profiles, with <i>P. kingianum</i> polysaccharides (PKPs) demonstrating a significantly higher glucose content compared to <i>P. sibiricum</i> polysaccharides (PSPs) and <i>P. cyrtonema</i> polysaccharides (PCPs). Infrared (IR) spectroscopy and derivative spectral processing affirm both structural similarities and quantitative differences in functional groups among the species. Multivariate analyses, including HCA, PCA, and OPLS-DA, confidently classify the 12 batches of polysaccharides into three distinct groups (PSPs, PCPs, and PKPs), exhibiting strong model robustness (PCA: R²X = 0.951, Q² = 0.673; OPLS-DA: R²Y = 0.953, Q² = 0.922). Importantly, PKPs from number S11 show exceptional in vitro antioxidant activity (DPPH scavenging), which directly correlates with their high monosaccharide content and distinctive spectral features. These findings establish a robust foundation for the quality assessment of <i>Polygonatum</i> polysaccharides as potential natural antioxidants in functional foods, positioning PKPs as leading candidates for dietary supplement development.