Difficulties in Differentiating Natural from Synthetic Alkaloids by Isotope Ratio Monitoring using ¹³C Nuclear Magnetic Resonance Spectrometry

Abstract

Within the food and pharmaceutical industries, there is an increasing legislative requirement for the accurate labeling of the productʼs origin. A key feature of this is to indicate whether the product is of natural or synthetic origin. With reference to this context, we have investigated three alkaloids commonly exploited for human use: nicotine, atropine, and caffeine. We have measured by ¹³C nuclear magnetic resonance spectrometry the position-specific distribution of ¹³C at natural abundance within several samples of each of these target molecules. This technique is well suited to distinguishing between origins, as the distribution of the ¹³C isotope reflects the primary source of the carbon atoms and the process by which the molecule was (bio)synthesized. Our findings indicate that labeling can be misleading, especially in relation to a supplied compound being labeled as “synthetic” even though its ¹³C profile indicates a natural origin.

Key words

NMR - alkaloid - nicotine - atropine - caffeine - synthetic - natural

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