Quantitative analysis of amygdalin and prunasin in Prunus serotina Ehrh. using 1H-NMR spectroscopy.

摘要

Introduction: Prunus serotina is native to North America but has been invasively introduced in Europe since the seventeenth century. This plant contains cyanogenic glycosides that are believed to be related to its success as an invasive plant. For these compounds, chromatographic- or spectrometric-based (targeting on HCN hydrolysis) methods of analysis have been employed so far. However, the conventional methods require tedious preparation steps and a long measuring time. Objective: To develop a fast and simple method to quantify the cyanogenic glycosides, amygdalin and prunasin in dried Prunus serotina leaves without any pre-purification steps using 1H-NMR spectroscopy. Methods: Extracts of Prunus serotina leaves using CH₃OH-d₄ and KH₂PO₄ buffer in D₂O (1:1) were quantitatively analysed for amygdalin and prunasin using 1H-NMR spectroscopy. Different internal standards were evaluated for accuracy and stability. The purity of quantitated 1H-NMR signals was evaluated using several two-dimensional NMR experiments. Results: Trimethylsilylpropionic acid sodium salt-d₄ proved most suitable as the internal standard for quantitative 1H-NMR analysis. Two-dimensional J-resolved NMR was shown to be a useful tool to confirm the structures and to check for possible signal overlapping with the target signals for the quantitation. Twenty-two samples of P. serotina were subsequently quantitatively analysed for the cyanogenic glycosides prunasin and amygdalin. Conclusion: The NMR method offers a fast, high-throughput analysis of cyanogenic glycosides in dried leaves permitting simultaneous quantification and identification of prunasin and amygdalin in Prunus serotina.