Top-down Metabolomic Approaches for Nitrogen-Containing Metabolites

Streamlining the processes that reveal heteroatom-containing metabolites and their biosynthetic genes is essential in integrated metabolomics studies. These metabolites are especially targeted for their potential pharmaceutical activities. By using a Fourier-transform ion cyclotron resonance–mass spectrometry (FTICR–MS) instrument, we provide top-down targeted metabolomic analyses using ultrahigh-resolution liquid chromatography–mass spectrometry (LC–MS), high-resolution matrix-assisted laser desorption/ionization (MALDI), and high-resolution imaging mass spectrometry (IMS) with 15N labeling of nitrogen-containing metabolites. In this study, we efficiently extract known and unknown chemicals and spatial information from the medicinal plant Catharanthus roseus, which sources several cancer drugs. The ultrahigh-resolution LC–MS analysis showed that the molecular formula of 65 N-metabolites were identified using the petals, peduncles, leaves, petioles, stems, and roots of the non- and 15N-labeled Catharanthu...