Study On Isolation, Preparation And Biological Activity Of Bamboo Leaves Polysaccharides

Bamboo leaves polysaccharides had anti tumor activity, antioxidation and immunoregulation. It had wide application prospects. This paper reported bamboo polysaccharide from four species of bamboo leaves, Phyllostachys heterocycla, Pleioblastus amarus, Dendrocalamopsis oldhami, and Acidosasa edulis. Determining the most suitable bamboo leaves polysaccharide extraction condition of supercritical CO2extraction. The bamboo polysaccharide was purified by ethanol grading and ion exchange column chromatography. The physical and chemical characteristics of monosaccharide were studied by modern analytical instruments. The antioxidant capacity of the bamboo leaves polysaccharide was studied preliminarily. The following are main results.1. We used supercritical CO2extraction to extract bamboo leaves polysaccharide. The static extraction and dynamic extraction were both exist in the extraction process. The temperature, pressure, extraction time and the amount of entrainer were investigated factors. We selected three levels of every factor and chose L9(34) orthogonal table to test. Bamboo leaves polysaccharide rate was measured for optimization. The optimum extraction condition was that extractor temperature was50℃, extraction pressure was40MPa. The ratio of modifier volume (mL) and the quality of bamboo leaves (g) was3. The static extraction and dynamic extraction were both existed in the extraction process. Time used for each extraction was1hour. The highest extraction rate of the four species of bamboo leaves was D. oldhami (6.816%), followed by A. edulism (5.498%), P.amarus (4.755%) and P. heterocycla (4.283%). The polysaccharide content in the extractions was13.311%(P. heterocycla),24.333%(P.amarus),29.894%(D. oldhami) and15.014%(A. edulism). Supercritical Fluid Extraction of bamboo leaves polysaccharide yield was significantly higher than the traditional water extraction, solvent extraction, enzymatic or microwave extraction. Supercritical CO2extract of bamboo leaves polysaccharide had advantages of high extraction efficiency, no pollution and low cost.2. Using the volume fraction of20%,30%,40%,50%,60%,70%ethanol to precipitate bamboo leaves polysaccharide. We measured the polysaccharide content and total antioxidant capacity of the six components. The result was that the volume fraction of70%ethanol precipitation was filtrated by exchanging chromatography on DEAE-cellulose column (DEAE-52). We studied the physical and chemical characteristics of the purified bamboo leaves polysaccharide using GPC system. The results indicated that most of bamboo leaves polysaccharide was the neutral polysaccharide. The molecular weight was5.051×104Da.3. We analyzed the monosaccharide component of the four species bamboo leaves polysaccharide by precolumn derivatization GC. The bamboo polysaccharide was hydrolyzed with trifluoroacetic (TFA), derivated by acetic anhydride and analyzed by gas chromatographic. The results showed that all of the four species of bamboo leaves polysaccharide contained mannose, rhamnose, galactose, glucose, arabinose, xylose and fucose. D. oldhami, P.amarus and P. heterocycla mainly contained glucose. The content of monosaccharide of the four species bamboo leaves polysaccharide was2.316～6.396mg/g. The highest polysaccharide content of the four species of bamboo leaves was D. oldhami (16.585mg/g), followed by A. edulism (12.804mg/g), P. heterocycla (8.255mg/g) and P.amarus (6.329mg/g). The content of glucose was most which was from30.3%to37.3%in the P.amarus, D. oldhami and P. heterocycla. The content of galactose is most in A. edulism. The content of glucose and galactose in D. oldhami was higher relatively. The percentage was58%in the seven kind of monosaccharide. The content of monosaccharide in the bamboo leaves polysaccharide of P. heterocycla was2.277mg/g after purifying. The mole ratio of rhamnose, fucose, arabinose, xylose, mannose, glucose and galactose was1.318:2.100:1.189:1.016:1:4.776:1.318.4. We studied the antioxidant activity of bamboo leaves polysaccharide of P. heterocycla. The result was that1gram bamboo leaves polysaccharide which was after purified equaled to3.927gram Vc, while1gram bamboo leaves polysaccharide which was not purified equaled to9.178gram Vc. The total antioxidant capacity of the purified polysaccharides of bamboo leaves is42.79%of the total anti-oxidative capacity of the bamboo leaves polysaccharides purified before. Bamboo leaves polysaccharides had strong total antioxidant ability. The reason may be due to crude bamboo leaves polysaccharide extracted by SFE having synergistic effect with non-polysaccharide, which increasing the antioxidant capacity of crude polysaccharide. The value of IC50of the ability of scavenging of DPPH was very close to Vc’s. This showed that the purified bamboo leaves polysaccharide DPPH free radical scavenging capacity was still high. These two experiments showed that the bamboo leaves polysaccharide was strong in vitro antioxidant capacity.In summary, this trial was the first time using supercritical CO2extraction to extract bamboo leaves polysaccharide. Supercritical CO2extraction had higher extraction rate, non-polluting, low-cost. We studied the monosaccharide composition by modern analytical instruments and anti-oxidation of bamboo leaves polysaccharide. The results of the study provide theoretical and data support for the deep processing and utilization of bamboo leaves resources. The data obtained important guiding significance for the rational use of biomass rich in bamboo leaves resources and the preparation of high content of bamboo leaves polysaccharide.