Optimization of Bioactive Polysaccharide Extraction from Protaetia brevitarsis seulensis Larvae Using Deep Eutectic Solvents

An optimized deep eutectic solvent (DES) method was developed to enhance polysaccharide extraction from Protaetia brevitarsis seulensis larvae (PBSL) compared to conventional water extraction (CWE). Among five choline chloride-based DESs, 40% aqueous choline chloride:glycerol (1:2) was optimal. The response surface methodology with a Box-Behnken design yielded precise conditions (78.1 °C, 1.6 h, and 1:21 g/g), achieving 18% higher yield and 38% greater purity than CWE. Both extracts were identified as acidic heteroglycans with similar monomeric profiles, but DES polysaccharides showed lower molecular weight, higher branching, improved morphology, and better stability. DES-extracted polysaccharides exhibited stronger antioxidant activity and more potent anti-inflammatory effects in lipopolysaccharide-stimulated RAW264.7 cells while promoting macrophage activation. These results suggest that DES extraction provides a more efficient strategy for producing high-purity, multifunctional PBSL polysaccharides, highlighting their potential applications in functional foods and nutraceuticals.