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

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.