Isolation,Purification And Biological Activity Of Polysaccharides From Pouteria Campechiana

The pouteria campechiana?Lucuma nervosa A.DC?is a perennial tropical fruit trees belonging to sapotaceae family,which is widely distributed in tropical and subtropical regions.Fruits and leaves have rich pharmaceutical value.Pulp has liver-protecting effects,and seeds and leaves are traditional medicines for treating inflammation,pain and ulcers.Polysaccharide is an important component of pouteria campechiana with good biological activity,but there are few reports on research of pouteria campechiana polysaccharides.In order to promote the in-depth research and development,the extraction process,separation and purification,structure characterization and activity of pulp and seed polysaccharides were studied by using pulp and seeds of pouteria campechiana as raw materials.The main conclusions were as follows:1.Pulp and seed polysaccharides?PCPP,PCZP?of pouteria campechiana were extracted by ultrasonic method,and extraction parameters were optimized by single factor experiment combined with response surface method.The optimum extraction conditions for pulp polysaccharide and seed polysaccharide were ultrasonic temperature 66,79?,liquid to material ratio 29,41 mL/g,ultrasonic time 72,69 min,ultrasonic power 400 W,and polysaccharide yield 19.89%,15.94%,respectively.2.The trichloroacetic acid method was used to remove protein from crude polysaccharides of pulp and seeds.After separation and purification by DEAE-52 cellulose column and Sephadex G-75 glucan gel column,the pure polysaccharide component of PCPP-11 and PCZP-11 were obtained,respectively.The molecular weights of PCPP-11 and PCZP-11 were 20019 Da and 67869 Da,respectively,and polysaccharide contents were91.56%and 90.78%,respectively.Both were white powders,solubled in water,insolubled in organic reagents,and were non-starch polysaccharides.3.The structure and morphology of PCPP-11 and PCZP-11 were analyzed by high performance liquid chromatography?HPLC?,infrared spectroscopy?FT-IR?,nuclear magnetic resonance?NMR?and scanning electron microscopy?SEM?.Both PCPP-11 and PCZP-11 were?-glycosides and did not contain uronic acid.PCPP-11 was mainly composed of glucose and galactose with a molar ratio of 85.17:9.92.PCZP-11 was mainly composed of glucose and mannose with a molar ratio of 86.65:4.62.The main glycosidic linkages of PCPP-11 were identified as?4)-?-D-Glc?1?and?3,6?-?-D-Glc?1?.The main glycosidic linkages of PCZP-11 were identified as?4?-?-D-Glc?1?and?6?-?-D-Glc(1?.SEM showed that PCPP-11 was a lamellar structure with a smooth and convex surface.PCZP-11 was a strip structure with a smooth surface.4.According to results of in vitro bioactivity experiments,PCPP-11 and PCZP-11 had ability to scavenge DPPH,ABTS,OH and O₂^-free radicals,and the removal ability of PCZP-11 was higher than PCPP-11.PCZP-11 had better inhibitory effect on?-glucosidase than control acarbose,while PCPP-11 had a weak inhibitory effect.PCZP-11 inhibited activity of Micrococcus tetragenus,Staphylococcus albus,and Bacillus cereus.PCPP-11 only inhibited activity of Micrococcus tetragenus and Bacillus cereus,and the bacteriostatic activity was lower than PCZP-11.PCZP-11 had stronger antioxidation,antibacterial and hypoglycemic effects than PCPP-11.