Response Surface Optimization of Ultrasound-Assisted Deep Eutectic Solvent Extraction of Bioactive Polysaccharides From Sword Bean (Canavalia gladiata (Jacq.) DC.) Pods.

Safe and functional natural active ingredients are a research hotspot in early intervention studies of chronic diseases. This study focuses on a polysaccharide (CGPs‑1) from sword bean (Canavalia gladiata (Jacq.) DC.) pods. Its optimal ultrasound-assisted extraction conditions were achieved with choline chloride/oxalic acid DES (2:1), 34% water, 21 mL/g, 65°C, 29 min at 280 W; the actual yield (33.24%) was consistent with the predicted value (33.96%). CGPs‑1 was identified as a pyran‑type polysaccharide, comprising rhamnose (Rha), glucuronic acid (GlcA), and galacturonic acid (GalA) in a molar ratio of 1.08:1:1.78. CGPs‑1 had IC50 values of 0.157 mg/mL (α‑glucosidase), 0.083 mg/mL (α‑amylase), 31.18 mg/mL (DPPH radicals), and 2.264 mg/mL (ABTS radicals), inhibited LPS‑triggered inflammatory response and LPS‑mediated neurotoxicity in BV2 cells, and also suppressed MPTP-induced inflammatory response in zebrafish larvae. Results indicate that CGPs‑1 exhibits antioxidant, hypoglycemic, anti‑neuroinflammatory and neuroprotective potentials, providing preliminary experimental support for further research and the development of functional‑food‑related products derived from sword bean pods.