棘托竹荪水溶性多糖理化性质、单糖组成和固体形貌研究

Physicochemical Properties, Monosaccharide Composition and Morphology of Water-soluble Polysaccharides Isolated and Purified from Dictyophora echino-volvata Zane

棘托竹荪是市场上常见的四类食用竹荪之一,具有多种生物活性。本文采用乙醇分级沉淀法从棘托竹荪提取物中分离得到3个多糖组分(DEP-4P、DEP-6P和DEP-8P),然后采用比色法测定中性糖、蛋白质和糖醛酸含量,采用高效液相凝胶渗透色谱法和离子色谱法分析相对分子质量和单糖组成,同时对其红外光谱特征和固体形貌特征进行表征。结果显示,乙醇分级沉淀可以有效分离纯度较高的棘托竹荪多糖组分,DEP-4P、DEP-6P和DEP-8P的得率依次为27.4%,6.1%和1.8%。3种多糖均表现出单一对称的液相色谱峰,且相对分子质量依次为2.1×10^4,6.5×10^3,1.9×10^3u。DEP-4P和DEP-6P主要由葡萄糖组成,而DEP-8P还有少量甘露糖。红外光谱显示竹荪多糖为典型的α-型葡聚糖。电镜观察发现DEP-4P和DEP-6P呈现片状结构,而DEP-8P则有较多丝状形貌。研究结果表明,乙醇分级沉淀可快速、高效分离棘托竹荪提取物中不同的多糖组分,为今后结构、功能研究及实际应用提供良好基础。

Dictyophora echino-volvata Zane,a kind of the edible Dictyophoraindusiata species,has various bioactivities.Three fractions,named as DEP-4P,DEP-6P and DEP-8P,were fractionated using gradual ethanol precipitation method from the water soluble extract of Dictyophora echino-volvata Zane.The yields of DEP-4P,DEP-6P and DEP-8P were 27.4%,6.1% and 1.8%,successively.The contents of neutral sugar in DEP-4P,DEP-6P and DEP-8P ranged from 96.2% to 88.2%.No protein and uronic acid were detected.DEP-4P,DEP-6P and DEP-8P were identified as polysaccharides with high purity by high performance gel permeation charomatograph method.The relative molecular weights of DEP-4P,DEP-6P and DEP-8P were calculated to be 2.1×10^4,6.5×10^3 and 1.9×10^3 u,successively,by referring to the molecular weights of dextran standards.Glucose was the major monosaccharide among the three fractions,while that there was trace amounts of mannose in DEP-8P.FT-IR spectra of the polysaccharides indicated that they may be α-glucans.Scanning electron micrographs showed that DEP-4P and DEP-6P performed as sheet-like appearance,while DEP-8P presented pod or line-like shape.All above,α-glucans with different molecular weights and topographic characteristics were successfully isolated from crude extract of Dictyophora echino-volvata Zane,which could lay a good foundation for further investigations in the structural features,functional proterties and applications.