Optimization of microwave-assisted extraction for Herba Patriniae polysaccharide and its impact on physicochemical properties, antioxidant and hypoglycemic capacities: Primary structure-activity relationship.

This study optimized microwave-assisted extraction (MAE) of Herba Patriniae polysaccharide (HPP) and systematically compared its yield, properties and bioactivities with hot water extraction (HWE) and ultrasonic-assisted cellulase extraction (UACE). MAE (43.92 min, 437.31 W, liquid-to-material ratio 17.68: 1) enhanced HPP yields by 487.85 % and 6.13 % over HWE and UACE, respectively, while improving key physicochemical properties, including increased total sugar (112-116 %), uronic acids (>368 %), and HWE-like monosaccharide composition but elevated galactose (58.54 %), arabinose (54.49 %), and galacturonic acid content (704.76 %), alongside diminished particle size (1216.74 nm) and molecular weight (600 kDa). Bioactivity assays showed MAE-derived HPP' superior antioxidant capacity (18-63 % higher DPPH/hydroxyl radical scavenging) and enzyme inhibition (6-50 % greater α-glucosidase and α-amylase activity). Oxidative stress and insulin resistance HepG2 revealed MAE boosted antioxidant enzyme activities (SOD: 1.81-fold vs model, 1.02-1.08-fold vs HWE/UACE; CAT: 3.01-fold vs model, 1.06-1.43-fold vs HWE/UACE; GST-Px: 1.57-fold vs model, 1.03-1.49-fold vs HWE/UACE) and reduced lipid peroxidation (decreased 166 % MDA vs model, 12.5-25 % vs HWE/UACE). Hypoglycemic effects involved upregulated hexokinase (1.23-fold vs model, 1.03-1.08-fold vs HWE/UACE) and pyruvate kinase (1.13-fold vs model, 1.04-1.08-fold vs HWE/UACE), with suppressed Glucose-6-phosphatase (decreased by 12.5 % vs model, 5.76-7.55 % vs HWE/UACE). MAE is a promising technique for preparation HPP with desirable bioactivities.