Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology (Incubation) in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology (Incubation) in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Int J Biol Macromol. 2018 May;111:587-594. doi: 10.1016/j.ijbiomac.2018.01.052. Epub 2018 Jan 12.
The bifidogenic effects of exopolysaccharide (EPS) of a medicinal fungus (Cordyceps sinensis) and a well-known food polysaccharide konjac glucomannan (KGM) with different molecular weight (MW) ranges were evaluated through in vitro experiments in liquid cultures of Bifidobacteria. Native EPS and KGM were partially degraded with power ultrasound (US) to improve the water solubility, and further hydrolysed with trifluoroacetic acid to much lower MW. The acid-hydrolysed fractions (EPS-AH and KGM-AH) supported the growth of all five tested bifidobacterial species, while the US-degraded high MW fractions, EPS-US and KGM-US, could only slightly support the growth of some species. All EPS fractions increased the acetic acid production of most bifidobacterial species. Most remarkably, the high MW EPS-US, EPS-AH and KGM-US fractions significantly enhanced the cell viability with much higher colony forming unit (CFU) counts, suggesting a protective effect of these high MW polysaccharides for the bacterial survival. The results have shown that MW was a significant factor on the bifidogenic properties of partially degraded EPS and KGM.
采用液体培养双歧杆菌的体外实验，评估了药用真菌（冬虫夏草）的胞外多糖（EPS）和一种众所周知的食物多糖魔芋葡甘露聚糖（KGM）的双歧杆菌促生作用，这两种多糖具有不同的分子量（MW）范围。天然 EPS 和 KGM 经功率超声（US）部分降解以提高其水溶性，然后用三氟乙酸进一步水解至更低的 MW。酸水解产物（EPS-AH 和 KGM-AH）支持所有五种测试双歧杆菌的生长，而 US 降解的高分子量部分，EPS-US 和 KGM-US，只能稍微支持某些物种的生长。所有 EPS 部分均增加了大多数双歧杆菌的乙酸产生。最显著的是，高分子量 EPS-US、EPS-AH 和 KGM-US 部分显著提高了细胞活力，菌落形成单位（CFU）计数更高，表明这些高分子量多糖对细菌存活具有保护作用。结果表明，MW 是部分降解的 EPS 和 KGM 的双歧杆菌促生特性的重要因素。
