Physicochemical characterization, antioxidant activity of polysaccharides from Mesona chinensis Benth and their protective effect on injured NCTC-1469 cells induced by H2O2

Polysaccharides MP-A, MP-U and MP-C were extracted from Mesona chinensis Benth by hot-alkali extraction (HAE), ultrasonic-assisted extraction (UAE) and cellulose-enzyme assisted extraction (CAE), respectively. The yields, physicochemical properties and antioxidant of polysaccharides were investigated. Results showed that the yields of MP-A (11.14%), MP-U (10.62%) and MP-C (9.70%) were similar, and they were all heteropolysaccharides with average molecular weights of 1.9 × 105 Da, 1.5 × 105 Da, 1.4 × 105 Da. Glucose, galactose, and galacturonic acid were the main monosaccharides in MP-A, MP-U and MP-C with molar ratios of 1.00:1.34:0.25, 1.00:2.49:0.19 and 1.00:2.95:0.84, respectively. MP-C extracted by CAE exhibited higher antioxidant activities in FRAP, DPPH, hydroxyl radical assays and the H2O2-induced injury cell model. The three extraction methods had only slight effects on chemical composition, while MP-C extracted by CAE exhibited the highest antioxidant activity, which could potentially be used for an addition ingredient as it was previously shown to have good gelling property in food products.