体外模拟消化液对金钗石斛的作用

采用体外模拟消化液，分别对金钗石斛超微/普通粉、水/醇提物、粗石斛碱和多糖进行实验，探究实 验组模拟消化液中化学成分的变化。实验测定石斛碱、多糖溶出率；运用高效液相色谱、3,5-二硝基水杨酸法 和阴离子色谱对多糖消化产物的分子质量、还原糖质量浓度和单糖组成进行分析；采用液相色谱-质谱联用仪对 多酚类化合物成分进行分析。结果表明：消化组中石斛碱溶出率不断增大，超微粉肠道消化液组溶出率最高达 （21.46±0.52）%，粗石斛碱消化液最低为（8.74±0.50）%；水提物组多糖溶出率高，在口腔和胃消化液中，超 微粉多糖溶出率比普通粉高；肠道消化液中的情况与之相反；多糖在消化过程中分子质量降低，还原糖质量浓度上 升，无单糖检出；多酚类物质的质量浓度普遍在模拟胃液中升高，在模拟肠液中降低。

Effect of Simulated Digestion in Vitro on Powders,Crude Extracts and Components of Dendrobium nobile Lindl. Stems

The effects of three simulated digestive juices on the in vitro digestion of submicron and common powders, water and alcohol extracts, and crude dendrobine and polysaccharide from Dendrobium nobile Lindl. stems were investigated by using a model gastrointestinal system. The dissolution rates of dendrobine and polysaccharide were evaluated. By using high performance liquid chromatography (HPLC), 3,5-dinitrosalicylic acid method and iron exchange chromatography, we determined the changes in the molecular weight, reducing sugar content and monosaccharide composition of polysaccharide after digestion. The polyphenols in digestive juices were analyzed by ultra-high performance liquid chromatographytandem mass spectrometry (UPLC-MS-MS). Results showed increasing dissolution rate of dendrobine during digestion. Submicron powder digestion showed the highest dendrobine dissolution rate of (21.46 ± 0.52)%. On the contrary, the lowest dissolution rate of (8.74 ± 0.50)% was observed for the crude dendrobine. The dissolution rate of polysaccharide from the water extract was the highest among all the samples. Furthermore, during oral and gastric digestion, the submicron powder showed a higher dissolution rate of polysaccharide compared to the common powder, whereas the opposite was observed during intestinal digestion. In addition, simulated gastrointestinal digestion reduced the molecular weight of polysaccharide, and increased reducing sugar content, but did not produce any monosaccharides. The polyphenols from Dendrobium nobile Lindl. showed an increasing trend in simulated gastric juice, but generally decreased in simulated intestinal juice.