Process optimization and effect of different extraction methods on the characteristics and activities of Herba Patriniae polysaccharides: A correlation analysis

The process of papain assisted hot water (WP), cellulase assisted hot water (WC), papain mixed cellulase assisted hot water (WPC), ultrasonic assisted papain (PU), and ultrasonic assisted cellulase (CU) for Patriniae polysaccharides (HPs) extraction were optimized using the indicate of polysaccharide yield, respectively. Then, the physicochemical characteristics, antioxidant and hypoglycemic activities of HPs were compared, with an additional correlation analysis between the characteristics and activities of HPs. The results showed that CU demonstrated the highest extraction rate at 30.50 % among all methods. Compared to previous hot water extraction (HW), the enzyme-assisted extraction increased molecular weight, reducing sugar, mannose, and glucose content of HPs, while ultrasound-assisted extraction lowered mannose and glucose content of HPs, and increased reducing sugar content of HPs. All HPs showed concentration-dependent hypoglycemic and antioxidant activities. Correlation analysis revealed that HPs with moderate galactose content, higher reducing sugar, protein, glucose, mannose, xylose, and molecular weight polysaccharide content would exhibit superior hypoglycemic and antioxidant activities, with CU-HPs expressing these excellent characteristics. Together with the exceptional polysaccharide yield, CU was a promising strategy to extract HPs, whose optimum process were: enzyme addition 2.5 %, solid–liquid ratio 1:25, ultrasonic power 150 W, ultrasonic time of 50 min.