山楂多糖的分离纯化及其对粪便菌群的影响

Isolation and purification of polysaccharides from hawthorn fruit and the effects on fecal microbiota

多糖是山楂中重要功能活性成分,具有免疫调节、抗炎、调节糖脂代谢、抗糖基化等多种有益于人体健康的功能活性。该研究采用水提醇沉法从新鲜山楂中提取多糖,经大孔吸附树脂AB-8脱色后先后通过Q-sepharose^(TM)Fast Flow阴离子交换树脂及Sephadex^(TM) G-500凝胶对山楂多糖进行分离纯化,收集得到组分HFP-2并对其单糖组成及结构特征进行分析。结果表明,HFP-2的总糖与蛋白质含量分别为(93.84±0.58)%和(5.41±0.05)%,其分子质量为2.60×10^(5)kDa,主要由半乳糖醛酸(36.91 mol%)、阿拉伯糖(28.11 mol%)、葡萄糖(15.02 mol%)、半乳糖(13.06 mol%)、鼠李糖(7.49 mol%)构成。结合傅里叶变换红外光谱分析HFP-2结构中官能团推测该组分为类似半乳糖醛酸为主链的果胶结构。体外粪便菌群发酵实验表明,HFP-2能够显著增加Phascolarctobacterium、Bacteroides、Prevotella、Roseburia等菌属的相对丰度(P<0.05)且促进乙酸、丙酸、异丁酸、丁酸等短链脂肪酸的生成。HFP-2能够通过调节肠道菌群多样性及代谢发挥益生作用,可作为益生元应用于功能食品。

Polysaccharides are important functional components in hawthorn fruit with health beneficial effects of immunomodulatory,anti-inflammation,regulation on glucose and lipid metabolism,and anti-glycation activities.In this study,polysaccharides were aqueous extracted from fresh hawthorn fruit and collected by alcoholic precipitation.Then,the collected polysaccharide fractions were subjected for decolorization using macroporous adsorption resin AB-8,and subsequently separated by Q-Sepharose TM Fast Flow anion exchange chromatography and Sephadex^(TM) G-500 gel chromatography.A homogenous polysaccharide fraction that denoted as HFP-2 was obtained and its chemical composition and structural features were further characterized.The total sugar and protein content of HFP-2 was(93.84±0.58)%and(5.41±0.05)%,respectively.HFP-2 was majorly composed by galacturonic acid(36.91 mol%),arabinose(28.11 mol%),glucose(15.02 mol%),galactose(13.06 mol%),and rhamnose(7.49 mol%),with an averaged molecular weight of 2.60×10^(5) kDa.Combined with the identified functional groups by Fourier transform infrared spectroscopy,HFP-2 could have a structure that similar with pectin with backbone of homogalacturonan.The prebiotic activity of HFP-2 was analyzed by in vitro fermentation with fecal microbiota.After 48 h fermentation,HFP-2 significantly(P<0.05)increased the relative abundance of genera Phascolarctobacterium,Bacteroides,Prevotella,and Roseburia.Moreover,the production of short chain fatty acids such as acetate,propionate,isobutyrate,and butyrate was significant increased after fecal microbial fermentation of HFP-2.Findings gained in this study indicated that HFP-2 exerted prebiotic effects through altered composition and metabolization of intestinal flora.Thus,HFP-2 could be potentially used as prebiotics in functional foods.