Application of comprehensive NMR‐based analysis strategy in annotation, isolation and structure elucidation of low molecular weight metabolites of Ricinus communis seeds

Introduction Powder-like extract of Ricinus communis seeds contain a toxic protein, ricin, which has a history of military, criminal and terroristic use. As the detection of ricin in this “terrorist powder” is difficult and time-consuming, related low mass metabolites have been suggested to be useful for screening as biomarkers of ricin. Objective To apply a comprehensive NMR-based analysis strategy for annotation, isolation and structure elucidation of low molecular weight plant metabolites of Ricinus communis seeds. Methodology The seed extract was prepared with a well-known acetone extraction approach. The common metabolites were annotated from seed extract dissolved in acidic solution using 1H NMR spectroscopy with spectrum library comparison and standard addition, whereas unconfirmed metabolites were identified using multi-step off-line HPLC-DAD-NMR approach. Results In addition to the common plant metabolites, two previously unreported compounds, 1,3-digalactoinositol and ricinyl-alanine, were identified with support of MS analyses. Conclusion The applied comprehensive NMR-based analysis strategy provided identification of the prominent low molecular weight metabolites with high confidence. Copyright © 2015 John Wiley & Sons, Ltd.