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 H-1 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 (C) 2015 John Wiley & Sons, Ltd.