Effects Of Bamboo Shoot Polysaccharides On Lipid Metabolism And Intestinal Flora

In this paper,response surface methodology(RSM)was used to optimize the extraction process of water-soluble polysaccharides(BSP)from bamboo(Phyllostachys edulis)shoots.The physical and chemical properties and functional characteristics of BSP were investigated.The effects of different concentrations of BSP on lipid metabolism and intestinal microflora in hyperlipidemic mice were studied.The main results are as follows:(1)The effects of material-to-liquid ratio,extraction temperature and extraction time on the extraction rate of water-soluble polysaccharides(BSP)were investigated by single factor and response surface methodology.The optimal extraction process conditions were obtained as follows:material-to-liquid ratio 1:27 g/mL,extraction temperature 78?,extraction time 4 h.The actual extraction rate of BSP was 4.18%.Chemical analysis showed that BSP contained 72.14%polysaccharide,9.76%uronic acid,0.95%protein and 0.04%sulfate.GC chromatographic analysis showed that BSP was composed of mannose,glucose,arabinose,xylose,rhamnose,and galactose with a molar ratios of 62.52:23.05:10.35:2.78:0.79:0.51,and it was a heterogeneous acidic polysaccharide.(2)Gel chromatography showed that BSP was mainly composed of polysaccharide with a relative molecular mass of 91.11 kDa and 4.55 kDa.The infrared spectroscopy analysis revealed that BSP is a mixed polysaccharide composed of pyranosyl.Scanning electron microscopy(SEM)observation revealed that BSP was irregular flake at 150×magnification,while the surface of BSP was loose network structure with micro particles at 3000×magnification.Particle size and potential analysis showed that the average particle size of BSP in solution was 915.70 nm,the average Zeta potential was-8.22 mV,and the particle size was relatively uniform and stable.The results of thermogravimetric analysis show that BSP has the best thermal stability below 220?,and it was prone to thermal decomposition only when the temperature exceeded 220?.Rheological studies showed that BSP is a weak gel-type polysaccharide with the shear thinning characteristics of non-Newtonian fluid.In vitro antioxidant experiments showed that BSP has a certain scavenging ability on DPPH and OH free radicals.(3)The effects of low,medium and high doses of BSP intervention on the lipid metabolism was researched by using animal model of high-fat mice.The experimental results showed that BSP intervention didn't affect food intake of mice,but could inhibit the weight gain of mice with high-fat diet.After 28 days of dietary intervention,the contents of TG and TC in the liver of mice in the high-dose BSP intervention group were 1.22 mmol/L and 4.76 mmol/L,respectively,significantly lower than that in model control group(MC group)of 3.39 mmol/L and 7.19 mmol/L(P<0.05).The serum levels of TC,TG and LDL-C in high-dose BSP intervention group were significantly decreased,while the HDL-C level was significantly increased(P<0.05),and the atherosclerosis index was significantly lower than that in MC group(P<0.01).Therefore,BSP can reduce blood lipid levels and regulate liver lipid metabolism in high-fat mice.(4)The effects of BSP intervention on intestinal microflora in hyperlipidemia mice was investigated.High-dose BSP intervention could inhibit the increase of pH in feces,and promote the contents of acetic acid,isovaleric acid,butyric acid,valeric acid and total short-chain fatty acid(SCFA)in high-fat mice(P<0.05).At the same time,BSP also promoted the growth and reproduction of intestinal probiotics Lactobacillus and Bifidobacterium,and inhibited the proliferation of harmful bacteria such as Escherichia Enterococcus.The results of high-throughput sequencing showed that BSP had no significant effect on ? diversity of the intestinal microflora of mice fed with high-fat diet,however,it could regulate the short-chain fatty acid composition of intestinal microflora and improve the imblance of intestinal microflora in high-fat mice.High dose of BSP could reduce the relative abundance of Firmicutes,increase the relative abundance of Bacteroides.It also promoted the increase of the relative abundance of Bifidobacterium Lactobacillus in high-fat diet mice,which indicated that BSP can restore and regulate the intestinal flora of mice fed with high-fat diet.