2D NMR Barcoding and Differential Analysis of Complex Mixtures for Chemical Identification: The Actaea Triterpenes

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• 作者：Feng Qiu ; James B. McAlpine ; David C. Lankin ; Ian Burton ; Tobias Karakach ; Shao-Nong Chen ; Guido F. Pauli
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：April 15, 2014
• 年：2014
• 卷：86
• 期：8
• 页码：3964-3972
• 全文大小：545K
• 年卷期：v.86,no.8(April 15, 2014)
• ISSN：1520-6882

文摘

The interpretation of NMR spectroscopic information for structure elucidation involves decoding of complex resonance patterns that contain valuable molecular information (未 and J), which is not readily accessible otherwise. We introduce a new concept of 2D-NMR barcoding that uses clusters of fingerprint signals and their spatial relationships in the 未鈭捨?coordinate space to facilitate the chemical identification of complex mixtures. Similar to widely used general barcoding technology, the structural information of individual compounds is encoded as a specifics pattern of their C,H correlation signals. Software-based recognition of these patterns enables the structural identification of the compounds and their discrimination in mixtures. Using the triterpenes from various Actaea (syn. Cimicifuga) species as a test case, heteronuclear multiple-bond correlation (HMBC) barcodes were generated on the basis of their structural subtypes from a statistical investigation of their 未_H and 未_C data in the literature. These reference barcodes allowed in silico identification of known triterpenes in enriched fractions obtained from an extract of A. racemosa (black cohosh). After dereplication, a differential analysis of heteronuclear single-quantum correlation (HSQC) spectra even allowed for the discovery of a new triterpene. The 2D barcoding concept has potential application in a natural product discovery project, allowing for the rapid dereplication of known compounds and as a tool in the search for structural novelty within compound classes with established barcodes.