牛膝多糖研究进展

牛膝多糖是从中药牛膝的干燥根里分离得到的果聚糖，相对分子质量小，水溶性好，易被人体吸收，具有广谱的免疫调节活性。牛膝多糖经结构修饰（硫酸酯化，磷酸酯化，羧甲基化，羟甲基化）后得到的一系列的多糖衍生物显示出更高的活性或新的生理活性，具有广阔的药物开发及应用前景。现对牛膝多糖的结构、分离、药理活性、及其衍生化修饰等方面的最新研究进展进行综述。     

The Immunomodulatory Properties of β-2,6 Fructans: A Comprehensive Review

Polysaccharides such as β-2,1-linked fructans including inulin or fructose oligosaccharides are well-known prebiotics with recognised immunomodulatory properties. In recent years, other fructan types covering β-2,6-linked fructans, particularly microbial levans, have gained increasing interest in the field. β-2,6-linked fructans of different degrees of polymerisation can be synthesised by plants or microbes including those that reside in the gastrointestinal tract. Accumulating evidence suggests a role for these β-2,6 fructans in modulating immune function. Here, we provide an overview of the sources and structures of β-2,6 fructans from plants and microbes and describe their ability to modulate immune function in vitro and in vivo along with the suggested mechanisms underpinning their immunomodulatory properties. Further, we discuss the limitations and perspectives pertinent to current studies and the potential applications of β-2,6 fructans including in gut health.     

Diet composition and age determine the effects of inulin–type fructans on intestinal calcium absorption in rat

Summary Background Although several studies in animals and humans have established that inulintype fructans (inulin, oligofructose, fructooligosaccharides) enhance intestinal Ca absorption, there are also reports that failed to demonstrate any effects of added fructans on Ca absorption. Aim of the study We investigated in a rat model what variables determine inulin actions on mineral absorption with special focus on the basic diet. Methods To determine apparent intestinal mineral absorption, whole body retention and mineral accumulation in bone, we performed feeding experiments with a balance technique by which mineral intake, faecal and urinary output are determined. Results In a first study we compared the effects of an inulin oligofructose mixture (0 and 10%,respectively) when added either to a standard diet or a semi–synthetic diet. Rats fed the semi–synthetic diet were younger (adolescent) than rats on standard diet (young adult). We observed that the apparent Ca absorption ratio was significantly increased by inulin and oligofructose only when provided in the semisynthetic diet and not in the standard diet that intrinsically already contained some fructans from wheat. In our second study with a semi–synthetic diet fed to growing (adolescent) rats, inulin and oligofructose increased not only Ca but also Mg and Zn absorption, whole body mineral retention and femur mineral content. Conclusion Inulin–type fructans at dietary levels of 10 % (w/w) do increase mineral absorption, retention and accumulation in bone in the case of Ca, Mg and Zn, but only when the basic diet for the control group contains no intrinsic fructans and when the mineral demand is particularly high as during growth.This work was in part supported by Orafti, Tienen, Belgium     

Extracellular polysaccharides of smooth and rough variants of Streptococcus salivarius

Abstract – Some, but not all strains of Streptococcus salivarius were demonstrated to occur in smooth (S) and rough (R) variants, growing in distinctly different colonies on sucrose-containing agar plates. Sucrosederived extracellular polysaccharides (EP) of NCTC 8666, ATCC9759S and R, ATCC13419S and R, IAS And R, and Tove S and R were isolated, puridied, and chemically studied. Extracellular enzymes of R variants yielded more water-insoluble than soluble material, while the opposite was true for 8 variants. The insoluble material consisted mainly of glucan, the soluble mainly of levan. Enzymatic hydrolysis suggested a predominance of α-1, 3linkages in the water-insoluble glucan. Cell-associated enzymes gave rise to cell-associated and -free EP. The cell-associated EP of sS variants was insoluble, while that of R variants contained water-insoluble glucan and water-soluble fructan. Cells coated with cell-associated EP flocculated due to interaction of the Ep, mainly by hydrogen bonding, in part by divalent cation bridging. The sucrose-derived EP gave rise to plaque deposit formation in sucrose broth cultures, S variant deposits being thin and firmly adherent to glass, R variant deposits being thick, rough, coherent, but only weakly adherent. The variant types were not altered by the curing agents ethidium bromide and acridine orange.     

果糖基转移酶表达相关影响因素的研究进展

能产生果糖基转移酶的细菌利用蔗糖作为代谢底物可以合成重要的胞外多糖果聚糖,后者供细菌在糖源缺乏时继续代谢生存,本文以糖源因素为主初步就影响果糖基转移酶表达水平的多种因素作一综述。     

Characterization of fructans and dietary fibre profiles in raw and steamed vegetables

Dietary fibre (DF) has many positive effects on human health associated with its functionality in the gastrointestinal tract. These benefits vary according to the type of DF. Vegetables can be a natural source of DF in the diet. However, to provide adequate nutritional advice, the content and profile of their various DF types must be characterised. This study aimed to determine the DF profile of 29 vegetables cultivated in Wallonia (Belgium) and the impact of steaming on these profiles. Using a combination of enzymatic, gravimetric and chromatographic methods, fructans, total dietary fibre (TDF), low- and high-molecular-weight soluble dietary fibre (SDF), and insoluble dietary fibre (IDF) were analysed. Results show that the DF content varies considerably among the 29 investigated vegetable varieties and species, but the influence of steaming is limited to a shift from IDF to high-molecular-weight SDF for 18 of the 29 tested vegetables, while fructans are preserved with not actual reduction in the DP.     

Processing of a cowpea–groundnut blend into a miso-like product

A traditional salt-miso process was used to produce a miso-like product from a 50–50 mixture of cowpea and groundnuts in a 60-day fermentation process as part of a study to determine the suitability of local legumes as raw materials for the production of miso. The koji was freshly prepared from a locally obtained rice and Aspergillus oryzae spores obtained from Japan. An old miso sample also obtained from Japan was used as the source of lactic acid bacteria. The physico-chemical changes in the product associated with the fermentation and the functional and quality characteristics of the final product were determined. The study demonstrated the possibility of processing the legume blend into a miso-like product. The physico-chemical, functional and quality characteristics of the final product showed the suitability of the product for its intended use as a soup base. The product had a high protein and a moderately high lipid content (about 25% and 29%, respectively), which could contribute to the nutritional contents of diets.     

菊粉类果聚糖对血甘油三酯和总胆固醇的影响——系统评价初探

目的探讨菊粉类果聚糖对人群的降脂作用。方法通过检索Medline、EMbase等国际期刊数据库和相关出版物的参考文献,以血浆总胆固醇和甘油三酯水平为分析指标的人体随机对照试验进行系统评价。由两位评价者独立阅读相关文献并提取数据,只有文献质量达到要求的研究才被纳入评价。最后共纳入9项研究进行评价。结果与对照组相比,菊粉类果聚糖能显著降低高脂血症人群的血浆总胆固醇和甘油三酯水平,而对血脂正常者无明显作用。结论系统评价的结果表明每日随食物摄入菊粉类果聚糖17g/d对高血脂人群有良好的降血脂作用。