Characterization and antioxidant activities of polysaccharides extracted from enzymatic hydrolysate of Ginkgo biloba leaves

Three high purified polysaccharide monomers (GBP11, GBP22, and GBP33) were obtained from enzymatic hydrolysate of Ginkgo biloba leave using DEAE-Sepharose Fast Flow column and Sephadex G-100 column, and their basic structural characterization were investigated by utilizing high-performance liquid chromatography, high-performance ion chromatography, and Infrared Spectroscopy. In addition, antioxidant activities of related polysaccharides were also evaluated. The results showed that the molecular weight of GBP11, GBP22, and GBP33 were 1.944 x 10(3) KDa, 5.167 x 10(3) KDa, and 45.98 KDa, singly, and they were mainly made up of glucose, galactose, arabinose, and rhamnose with a molar ratio of 62.2:1.98:3.84:1.24, 3.57:68.0:4.67:0.36 and 5.34:48.8:1.70:8.97, respectively. Moreover, GBP22, GBP, and GBP11 demonstrated the strongest free radical scavenging activity on DPPH, ABTS, and superoxide anion, showing that they have potential application value on the functional food and cosmetic industry. Practical applicationsEnzymatic hydrolysate of Ginkgo biloba leaves includes lots of carbohydrate, it will cause eutrophication and environment pollution if it is directly poured out. This research indicates that carbohydrate extracted from enzymatic hydrolysate of Ginkgo biloba leaves are made up of different polysaccharide monomers with various molecular weight and monosaccharide composition. Moreover, these polysaccharide monomers possess appreciating antioxidant activities. Therefore, this research could lay a foundation for the high-value application of polysaccharides in functional food and cosmetic industry, and provide theoretical reference for the treatment of waste water.