亲水/反相二维色谱法制备桔梗中的三萜皂苷

建立了亲水/反相二维色谱用于制备桔梗中三萜皂苷单体的方法。桔梗经水煮醇沉、反相和亲水两种模式的固相萃取后得到三萜皂苷类组分。选定XAmide色谱柱（150 mm×20 mm，5 μm），以乙腈和水为流动相，在亲水色谱模式下进行组分制备。选择时间触发模式，以1 min为单位进行馏分收集，得到6~25 min之间的20个三萜皂苷精细组分。以第18个馏分（JG23）为例，在反相色谱模式下采用Atlantis Prep T3色谱柱（100 mm×30 mm，5 μm）制备，得到两个单体化合物。通过质谱和核磁共振对其进行定性，确定分别为deapi-platycoside E和platycoside E。实验结果表明，该制备方法具有好的正交选择性，对于复杂样品中三萜皂苷类化合物的分离纯化有一定的借鉴意义。

Preparation of triterpene saponins from Platycodon grandiflorum by two-dimensional hydrophilic interaction liquid chromatography-reversed phase liquid chromatography

A two-dimensional (2-D) preparative liquid chromatography method was developed for the preparation of triterpene saponins from Platycodon grandiflorum using hydrophilic interaction liquid chromatography (HILIC) coupled with reversed phase liquid chromatography (RPLC). At first, the crude extract was obtained from Platycodon grandiflorum by boiled alcohol precipitation. Then, the concentrated crude extracts were continuously pretreated using solid phase extraction (SPE) under reversed-phase and hydrophilic-phase modes to remove the impurities. Subsequently, XAmide column (150 mm×20 mm, 5 μm) was selected to separate the triterpene saponin constituents under HILIC mode using water and acetonitrile as mobile phases. From 6 min to 25 min, each fraction was collected per minute under time-triggered mode and 20 fractions were collected. The 18th fraction (JG23) was selected for further purification. The column of Atlantis PrepT3 (100 mm×30 mm, 5 μm) was chosen and two monomeric compounds were obtained. The two compounds with over 90% purity were identified as deapi-platycoside E and platycoside E with mass spectrometry (MS) and nuclear magnetic resonance (NMR). This 2-D HILIC-RPLC method with high orthogonality can be used in the preparation of triterpene saponins from natural products.