In Vitro Lipid-lowering Activity,Purification,Structural Characterization Of Polysaccharides Fractionated From Passiflora Edulis Peel

Passiflora edulis Sims is an evergreen climbing grassy vine of the genus Passifloraceae.In this study,homogeneous polysaccharide components from Passiflora edulis Sims peel were isolated and purified,and their structure characterization and lipid-lowering activity in vitro were studied.The specific results are as follows:(1)The crude polysaccharide WPEP was obtained from the Passiflora edulis Sims peel by hot water extraction with a yield of 9.56 ± 0.42%.The WPEP was isolated and purified by DEAE-52 cellulose ion column and Sepharose CL-6B gel column.Four purified components,WPEP-F1,WPEP-F2,WPEP-F3 and WPEP-F4,were obtained with the yield of 11.08 ± 1.91%,30.50 ± 2.50%,9.74 ± 0.88% and 6.50± 0.50%,respectively.The yield of WPEP-F2 was the highest among all the purified components.The molecular weights were 31.10 KDa,9.22 KDa,14.11 KDa,29.75 KDa,respectively.HPGPG showed that the purified polysaccharide samples had high purity.(2)The results of physical and chemical properties showed that the total sugar content of WPEP,WPEP-F1,WPEP-F2,WPEP-F3 and WPEP-F4 were: 57.27 ±0.27%,52.93 ± 0.59%,77.63 ± 0.45%,48.70 ± 0.45% and 54.70 ± 0.54%.The protein content of polysaccharide components decreased.Compared with WPEP,the intrinsic viscosity and solubility of WPEP-F1,WPEP-F2,WPEP-F3 and WPEP-F4 are increased,and WPEP-F2 has the highest intrinsic viscosity and solubility.(3)WPEP-F1 was mainly composed of Glu,Gal,Man and Ara,while WPEP-F2,WPEP-F3 and WPEP-F4 were mainly composed of Gal A.Infrared chromatography showed that the separation and purification did not change the functional groups of polysaccharides.The SEM showed that the appearance of WPEP-F1 was granular,and the other components were mainly blocky and flake.Congo red experiment shows that WPEP-F2 has triple helix structure.XRD results show that WPEP and its components exhibit low crystalline or amorphous properties.(4)WPEP and its purified components have higher adsorption effect on oil.The cholesterol binding capacity of WPEP,WPEP-F1,WPEP-F2,WPEP-F3 and WPEP-F4 were 73.36%,78.17%,78.68%,77.03%,77.48% and 78.54%,respectively.WPEP-F2 has the highest cholesterol binding ability and the best binding effect on taurocholic acid,deoxycholic acid and glyamine cholic acid,which are 50.87%,69.12%,30.22% and 78.68%,respectively.The binding activity of WPEP-F2 to lipid,cholesterol and bile acid is related to its high viscosity,porous appearance and triple helix structure.The purified polysaccharide components had a good inhibitory effect on pancreatic lipase,pancreatic cholesterol lipase,α-amylase and α-glucosidase,indicating that the purified polysaccharide from Passiflora edulis Sims peel had certain lipid-lowering and hypoglycemic ability in vitro.