Extraction Technology And Characteristics Of Antioxidant And Antimicrobial Activities Of Polysaccharide In Galla Chinensis

Polysaccharide is very important substance in living creature or plants. Because of its various bioactivities and extensive usages in functional foods and pharmoceuticals, research on polysaccharide has gained increasing attention. Galla Chinensis has been used for various purposes in healthcare and disease treatments, but research on polysaccharide in Galla Chinensis has not been reported.The objectives of this research were to obtain optimal techniques to extract maximal yield of polysaccharide, and to determine scavenging activities to free radicals and antibacterial activities of polysaccharide from Galla Chinensis. Four experiments were performed. In experiment 1, the effects of extraction time, temperature, solid-solvent ratio, particle size of material and ultrasonic power on extraction yields of polysaccharide from Galla Chinensis were determined individually. Based on these results, a quadratic regression rotational combinational design was applied to establish a regression model and to estimate the optimal conditions for maximal extraction yield. The results showed that the optimal extraction conditions were 1:18.6 of solid-solvent ratio and 250W of ultrasonic power for 33.7min. In experiment 2, the effects of rotation speed, extraction time, solid-solvent ratio and particle size of material on extraction yields of polysaccharide from Galla Chinensis were determined individually. Based on these results, an orthogonal experiment design was applied to establish a regression model and to estimate the optimal conditions for maximal extraction yield. The results showed that the optimal extraction conditions were 1:40 of solid-solvent ratio and 13,000 rpm of rotation speed for 20 min. In experiment 3, the capacities of polysaccharide from Galla Chinensis for scavenging of free radicals were investigated. Fenton reaction to produce·OH and pyrogallol to produce O₂^-·was used. The results stated that polysaccharide of ultrasonic wave method and crushing method has the best scavenging rate to·OH and O₂^-·. In the final experiment, the effectiveness of polysaccharide for antimicrobial activities was evaluated. The results indicated that polysaccharide in Galla Chinensis had inhibitory effects to Escherichia coli and Staphylococcus aureus, and didn't have inhibitory effects to Salmonella.This research suggested that extraction of polysaccharide from Galla Chinensis be feasible and its extracted polysaccharides have large potentials in application in functional foods.