Isolation, Purification, Structural Analysis And Antioxidant Activity Of Polysaccharides From

Prunus tomentosa Thunb is a plant of Rosaceae Prunus wild or semi wild plants, which is widely distributed and nutrient-rich in vitamins, anthocyanins, minerals, polysaccharides and amino acid etc. And also has some medicinal value, such as antioxidant, anti-inflammatory, anti freezing injury effect. Prunus tomentosa Thunb is currently reported about its nutrient analysis, and its deep processing, such as the juice, the wine, has been developed. But the active ingredients and their pharmacological effects which it contains has been less studied, and the study of the polysaccharide of Prunus tomentosa Thunb has not been reported. For the comprehensive development and utilization of this wild plant resources, in this work, choose the fruit of Prunus tomentosa Thunb as raw material. Study on the extraction process, isolation, purification, structure and antioxidant activity in vitro of Prunus tomentosa Thunb polysaccharides, the main conclusions are as follows:(1) Extraction technology of polysaccharides from Prunus tomentosa Thunb with hot water was studied. On the base of the single-factor experiments, using response surface method to optimize the test design, the experimental conditions were optimized as follows:liquid/solid ratio,30:1mL/g; extraction number,2; extraction time,2.3h; extraction temperature,83℃;and the extraction ratio of the polysaccharides was7.52%.(2) The Crude polysaccharides of Prunus tomentosa Thunb were fractionated by DEAE-52cellulose column to obtain PTTP-A, PTTP-B, PTTP-C three components, three components for further purification by SephadexG-100gel column chromatography to obtain PTTP-a, PTTP-b, PTTP-c three components respectively.(3) The analysis of HPLC determination showed that PTTP-a, PTTP-b, PTTP-c were the purified products, and the average molecular weight was6.26×105Da,7.97×105Da,6.02×105Da respectively. Gas chromatography(GC) analysis showed that the monosaccharide composition of PTTP-a, PTTP-b were basically same, they were composed of arabinose, mannose, rhamnose and glucose, PTTP-c was composed of galactose, mannose, xylose, arabinose, rhamnose and glucose.(4) IR spectroscopy and1HNMR spectroscopy showed that the absorption peak of PTTP-a, PTTP-b, PTTP-c were all near at3400cm-1,2930cm-1,1617cm-1,1426cm-1,1385cm"1,1226cm-1,1076cm-1,862cm-1, they were all the characteristics absorption peak of polysaccharide, and three kinds of polysaccharides were all containing β-linked glycosidic bond.(5)’HNMR spectrum showed that proton signal peaks of PTTP-a, PTTP-b and PTTP-c were typical signals of polysaccharide because they were concentrated in the range of3.18-5.13ppm. It can be roughly inferred that three polysaccharides all contained two kinds of (3-pyranose and a-pyranose residues. And most of the proton signal peaks were less than5.0ppm, showed that they were mainly β-glycosidic linkage, and the analysis results were consistent with the analysis of IR spectra.(6) The evaluation of antioxidant activity in vitro results showed that, the crude polysaccharide of Prunus tomentosa Thunb had reducing capacity, also had a scavenging effect on·OH、O2-·and DPPH·. At the same time, The scavenging capacity of crude polysaccharide on three kinds of free radical had increased with its increasing concentration.