Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China.
Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China.
J Chromatogr A. 2024 May 10;1722:464857. doi: 10.1016/j.chroma.2024.464857. Epub 2024 Mar 30.
Epimer separation is crucial in the field of analytical chemistry, separation science, and the pharmaceutical industry. No reported methods could separate simultaneously epimers or even isomers and remove other unwanted, co-existing, interfering substances from complex systems like herbal extracts. Herein, we prepared a heptapeptide-modified stationary phase for the separation of 1R,2S-(-)-ephedrine [(-)-Ephe] and 1S,2S-(+)-pseudoephedrine [(+)-Pse] epimers from Ephedra sinica Stapf extract and blood samples. The heptapeptide stationary phase was comprehensively characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The separation efficiency of the heptapeptide column was compared with an affinity column packed with full-length β-AR functionalized silica gel (β-AR column). The binding affinity of the heptapeptide with (+)-Pse was 3-fold greater than that with (-)-Ephe. Their binding mechanisms were extensively characterized by chromatographic analysis, ultraviolet spectra, circular dichroism analysis, isothermal titration calorimetry, and molecule docking. An enhanced hydrogen bonding was clearly observed in the heptapeptide-(+)-Pse complex. Such results demonstrated that the heptapeptide can recognize (+)-Pse and (-)-Ephe epimers in a complex system. This work, we believe, was the first report to simultaneously separate epimers and remove non-specific interfering substances from complex samples. The method was potentially applicable to more challenging sample separation, such as chiral separation from complex systems.
差向异构体分离在分析化学、分离科学和制药行业中至关重要。目前尚无报道的方法可以同时分离差向异构体甚至对映异构体，并从草药提取物等复杂体系中去除其他不需要的、共存的、干扰物质。在此，我们制备了一种七肽修饰的固定相，用于从麻黄草提取物和血液样品中分离 1R,2S-(-)-麻黄碱[(-)-Ephe]和 1S,2S-(+)-伪麻黄碱[(+)-Pse]差向异构体。通过扫描电子显微镜、X 射线光电子能谱和傅里叶变换红外光谱对七肽固定相进行了全面表征。比较了七肽柱和全长β-AR 功能化硅胶填充的亲和柱（β-AR 柱）的分离效率。七肽与(+)-Pse 的结合亲和力是与(-)-Ephe 的 3 倍。通过色谱分析、紫外光谱、圆二色分析、等温滴定量热法和分子对接广泛研究了它们的结合机制。在七肽-(+)-Pse 复合物中明显观察到增强的氢键。这些结果表明，七肽可以在复杂体系中识别(+)-Pse 和(-)-Ephe 差向异构体。我们相信，这项工作首次报道了同时从复杂样品中分离差向异构体并去除非特异性干扰物质的方法。该方法可能适用于更具挑战性的样品分离，如从复杂体系中进行手性分离。
