铁皮石斛叶多糖的提取及其免疫活性测定

Extraction of Polysaccharide from the Leaves of Dendrobium officinale and Its Immunomodulatory Property

应用响应面法对铁皮石斛叶多糖的提取进行优化,并对多糖初步纯化。将铁皮石斛叶多糖作用于脂多糖(LPS)诱导的人体单核细胞(THP-1),测定对THP-1细胞活性及活性氧(ROS)形成的影响,以研究其免疫活性。结果表明:铁皮石斛叶多糖的最佳提取工艺为温度70.61℃、时间1.96 h、料液比20:1,此时多糖得率可达13.56%,与理论预测值基本吻合。利用透析袋除去多糖中小分子杂质,经凝胶柱Sephadex G-100初步纯化,获得一种纯化多糖,即命名为DLP。将DLP作用于THP-1,随着浓度增大(0.5~100μg/mL),DLP能剂量依赖性地抵抗LPS诱导的细胞毒;5μg/mL时,THP-1细胞活性基本完全接近对照组。此外,5μg/mL铁皮石斛叶多糖可有效抑制LPS诱导的细胞内ROS产生。因此,采用响应面法提取并经凝胶柱纯化得到的铁皮石斛叶多糖具有良好免疫活性。

Response surface methodology was utilized to optimize the extraction process of polysaccharide from Dendrobium officinale,and the polysaccharide was preliminarily purified.The immunomodulatory property was evaluated by investigating effects of the polysaccharide on the cell viability and reactive oxygen species(ROS)formation in lipopolysaccharide(LPS)induced-human monocytic cells(THP-1).The optimum condition for the extraction of polysaccharide was found to be at 70.61℃for 1.96 h with a material/solvent ratio of 1:20(g/mL).Under this condition,the measured values of polysaccharide yield was 13.56%,which was in agreement with the predicted value.The polysaccharide was purified by dialysis bag and Sephadex G-100,and the purified polysaccharide was named DLP.With DLP concentration increasing(0.5~100μg/mL),DLP could protect against LPS-induced cell toxicity in dosage,as well as inhibit reactive oxygen species(ROS)formation of THP-1.At 5μg/mL,the activity of THP-1 cells was almost completely close to the control group.These findings suggest that DLP extracted using Response surface method and purified by Sephadex G-100 had good immunomodulatory property.