School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan.
Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan.
Molecules. 2021 Mar 13;26(6):1599. doi: 10.3390/molecules26061599.
A highly specific and sensitive proton nuclear magnetic resonance (H-NMR) method has been developed for the quantification of ephedrine alkaloid derivatives in herbal commercial prescriptions. At the region of δ 4.0 to 5.0 ppm in the H NMR spectrum, the characteristic signals are separated well from each other, and six analogues in total, methylephedrine (ME), ephedrine (EP), norephedrine (NE), norpseudoephedrine (NP), pseudoephedrine (PE), and methylpseudoephedrine (MP) could be identified. The quantities of these compounds are calculated by the relative ratio of the integral values of the target peak for each compound to the known concentrations of the internal standard anthracene. The present method allows for a rapid and simple quantification of ephedrine alkaloid derivatives in -related commercial prescriptions without any preliminary purification steps and standard compounds, and accordingly it can be a powerful tool to verify different species. In comparison to conventional chromatographic methods, the advantages of this method include the fact that no standard compounds are required, the quantification can be directly performed on the crude extracts, a better selectivity for various ephedrine alkaloid derivatives, and the fact that a very significant time-gain may be achieved.
已开发出一种高特异性和高灵敏度的质子磁共振（H-NMR）方法，用于定量分析草药商业配方中的麻黄碱衍生物。在 H NMR 光谱的 δ 4.0 至 5.0 ppm 区域，特征信号彼此分离良好，总共可以鉴定出六种类似物，即甲基麻黄碱（ME）、麻黄碱（EP）、去甲麻黄碱（NE）、去伪麻黄碱（NP）、伪麻黄碱（PE）和甲基伪麻黄碱（MP）。这些化合物的含量通过目标峰的积分值与已知浓度的内标蒽的相对比值来计算。该方法无需任何初步纯化步骤和标准化合物即可快速、简单地定量分析相关商业配方中的麻黄碱衍生物，因此它可以成为验证不同物种的有力工具。与传统的色谱方法相比，该方法的优点包括不需要标准化合物、可以直接对粗提物进行定量、对各种麻黄碱衍生物具有更好的选择性以及可以大大节省时间。
