Krämer P, Wincierz U, Grübler G, Tschakert J, Voelter W, Mayer H
University of Stuttgart-Hohenheim, Maintal, Germany.
Arzneimittelforschung. 1995 Jun;45(6):726-31.
Polysaccharides, isolated from the lichen Cetraria islandica, have antimicrobial effectiveness. For pharmaceutical applications the two glucan components lichenan and isolichenan as well as the galactomannan component are of actual interest. Especially the a-glucan isolichenan ist used as an active ingredient in cough lozenges. The conditions for the extraction of the raw material, mainly pH and temperature, have a strong influence on the yield of lichenan, isolichenan, and galactomannan, and also on the amount of tannins in the extract. Target products and also by-products give higher extraction yields with increasing extraction temperatures. Hot water extraction with subsequent fractionation of the extracted polysaccharides by multiple freezing/thawing steps and water removal applying ethanol and ether permitted the isolation of the target polysaccharides in preparative quantities. Tannins were removed by reversed phase chromatography. IR and NMR spectroscopy were used for structural characterization of lichenan and isolichenan. After optimization of the hot water extraction process no significant lower extraction and fractionation yields have been obtained compared to the established tricky DMSO extraction procedure.
从冰岛衣（Cetraria islandica）地衣中分离出的多糖具有抗菌功效。对于药物应用而言，两种葡聚糖成分地衣聚糖和异地衣聚糖以及半乳甘露聚糖成分具有实际意义。特别是α-葡聚糖异地衣聚糖被用作止咳含片的活性成分。原料提取的条件，主要是pH值和温度，对地衣聚糖、异地衣聚糖和半乳甘露聚糖的产量以及提取物中单宁的含量有很大影响。目标产物以及副产物随着提取温度的升高而获得更高的提取产率。通过多次冷冻/解冻步骤对提取的多糖进行后续分级分离，并用乙醇和乙醚去除水分的热水提取法能够以制备量分离出目标多糖。通过反相色谱法去除单宁。红外光谱和核磁共振光谱用于地衣聚糖和异地衣聚糖的结构表征。与既定的复杂二甲基亚砜提取方法相比，在优化热水提取工艺后，未获得显著更低的提取和分级产率。
