铁皮石斛茎部和叶部多糖的性质和活性

Characterization and Bioactivity Analysis of Dendrobium officinale Stem and Leaf Polysacchride

铁皮石斛是一种含有多种活性物质的名贵中药,目前主要利用其茎部进行活性和结构等方面的研究。作者通过研究和比较铁皮石斛茎部和叶部中的各种物质的质量分数和分布,发现茎部与叶部中物质组成相同,但茎部中多糖和石斛碱质量分数分别是叶部的2.71和3.02倍,而脂溶性成分和粗蛋白在叶部的质量分数要明显高于茎部。将提取后的茎部和叶部多糖进行分析,发现两种多糖的单糖组成具有较大差异,茎部多糖主要由甘露糖和葡萄糖组成,摩尔比为3.07∶1,叶部多糖主要由甘露糖、葡萄糖、半乳糖和阿拉伯糖组成,摩尔比为8.81∶1∶0.57∶0.37。此外,茎部和叶部多糖特性粘度分别为56.26、8.05 dL/g,与之对应的相对分子质量分别为1 207000和318 000,为高相对分子质量高粘度的生物大分子。在抗氧化活性实验中,清除DPPH自由基的结果显示,叶部多糖明显优于茎部多糖,表明其具有较高的抗氧化应用价值。在对提取条件中的温度、提取时间和料液比进行考察后,最终确定了茎部和叶部多糖提取的最优条件。

Dendrobium officinale is a precious medicinal plant containingmany bioactive compounds and its stem was the main subject for structure and bioactivity research. In this study,the types and contents of active compounds in D. officinale stem and leaf were compared. Although D. officinale stem and leaf had similar compounds,the content of polysaccharide and dendrobine in stem was 2.71 and 3.02 times as high as in leaves,while the content of fat-soluble composition and crude protein in leaves was significantly higher than that in stem. After monosaccharide composition analysis of purified stems and leaves polysaccharide,D. officinalestem polysaccharide(DOSP) was composed of mannose and glucose with mole ratio of 3.07:1. However,D. officinale leaf polysaccharide(DOLP) mainly contained mannose,glucose,galactose and arabinose with mole ratio8.81∶1∶0.57∶0.37. In addition,the intrinsic viscosity and of DOSP was 56.26 dL/g and DOLP was 8.05 dL/g,while the corresponding molecular weight of DOSP and DOLP were 1 207 000 and 318 000,respectively. The results of free radical scavenging capacity shows that DOLP has higher DPPH free radical scavenging capacity than DOSP indicating a high potential for applied as theantioxidant.Finally the extracted condition of DOSP and DOLP was optimized by comparing various temperatures,extracted times and solid-liquid ratio to enhance the yield of this active compound.