Fengling Yang, Yihong Tan, Wenlin Zhou, Cui Li, Cuilan Huang, Haiyi Zhong, Lini Huo, Peiyuan Li
Plant-derived polysaccharides represent an important class of bioactive natural products with wide applications in functional foods and pharmaceuticals. This study developed an efficient and eco-friendly deep eutectic solvent (DES)-based method for the extraction of Siraitia grosvenorii polysaccharides (SGP). The DES extraction process was optimized using a combined approach of Response Surface Methodology (RSM) and a Multi-Layer Perceptron Artificial Neural Network (MLP-ANN), with key parameters including molar ratio, moisture content, and liquid-to-solid ratio. Density functional theory (DFT) calculations provided molecular-level insight into the hydrogen-bonding interactions governing the DES system. The optimized DES extraction with ethanol precipitation (SGP-DE) resulted in a higher polysaccharide yield (88.47 ± 0.84%) compared to conventional hot water extraction (SGP-W, 65.39 ± 0.38%), along with a smaller molecular weight and more homogeneous structure. Structural analyses indicated that the DES-extracted SGPs were amorphous and exhibited improved thermal stability. In vitro bioactivity evaluations revealed that SGP-DE and SGP-DM (DES with methanol precipitation) possessed significantly enhanced inhibitory activity against α-amylase and α-glucosidase, as well as superior antioxidant capacity, attributable to their optimized structural properties. These findings establish DES as a highly effective and sustainable alternative for extracting high-value polysaccharides, providing a strong foundation for their application in health-promoting products.