天然产物是相当复杂的样品，包含大量从极性到非极性、从小分子到大分子的化合物，以及众多结构相似的同系物/类似物，为生物活性药物的发现创造了巨大的机遇和宝藏。为了更好地了解复杂的天然产物并控制其质量，用于充分分离化学成分和跟踪潜在生物活性成分的强大分析技术非常重要。研究组提出了一种双向β-环糊精(β-CD)改性色谱固定相，用于分离蟾蜍中提取的蟾蜍二烯内酯的设计理念。Bufadienolides可分为结构和极性差异显着的蟾蜍毒配体(AAUBs)和蟾蜍毒素(AACBs)两类。β-CD的疏水腔可以包裹AACBs的类固醇部分，而暴露在β-CD表面的羟基与AACBs的精氨酸部分有很强的亲水相互作用。等温滴定量热法和氢核磁共振滴定实验进一步验证了本设计的合理性。此外，β-CD基固定相可作为亲水材料构建HILIC×RPLC 2D分离模式用于AACBs的分离，也可作为反相材料构建RPLC×RPLC 2D分离模式用于AACBs的分离。AAUB的分离具有良好的正交性。该研究将为天然产物的高效二维分离开辟一条途径并提供新的见解。
相关成果发表在分离领域专业期刊《色谱A》，第一作者是华东理工大学盛骞莹老师。以上研究工作得到国家自然科学基金项目、我所创新特区组启动基金、兴辽英才计划等项目的支持。
High-efficiency Two-dimensional Separation of Natural Products Based on β-Cyclodextrin Stationary Phase Working in Both Hydrophilic and Reversed Hydrophobic Modes
Qianying Sheng, Ling Wang, Leyuan Zhang, Xue Wang, Shengxu Qian, Minbo Lan,* Guangyan Qing,* Xinmiao Liang
Journal of Chromatography A 2022, DOI: 10.1016/j.chroma.2022.463069
Natural products are rather complex samples containing a large number of compounds ranging from polar to nonpolar, small molecules to macromolecules, as well as numerous homologs/analogs with quite similar structures, which create great opportunities and treasures for discovery of bioactive drugs. For the purpose of better understanding the complex natural products and controlling their qualities, powerful analytical techniques for adequately separating chemical constituents and tracking potentially bioactive components are quite essential. Here, a design concept of bidirectional β-cyclodextrin (β-CD)–modified chromatographic stationary phase toward separation of bufadienolides extracted from toad is proposed. Bufadienolides could be divided into two classes: toad venom ligand (AAUBs) and toad toxin (AACBs) with remarkable differences in structures and polarity. The hydrophobic cavity of β-CD can encapsulate the steroid part of AACBs while the hydroxyls exposed on the β-CD surface have strong hydrophilic interactions with the arginine part of AACBs. Isothermal titration calorimetry and hydrogen nuclear magnetic resonance titration experiment further validate the rationality of this design. Furthermore, the β-CD-based stationary phase can be used as a hydrophilic material to construct a HILIC×RPLC 2D separation mode for the separation of AACBs, also works as a reverse phase material to construct a RPLC×RPLC 2D separation mode for the separation of AAUBs with good orthogonality. This study will open an avenue and provide a novel insight for high-efficiency two-dimensional separation of natural products.
