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Identification of metabolites in coriander seeds ( Coriandrum Sativum L .) aided by ultrahigh resolution total correlation NMR spectroscopy
Author(s) -
Verma Ajay,
Parihar Rashmi,
Baishya Bikash
Publication year - 2019
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4850
Subject(s) - chemistry , coriandrum , sativum , nuclear magnetic resonance spectroscopy , two dimensional nuclear magnetic resonance spectroscopy , heteronuclear single quantum coherence spectroscopy , spectroscopy , proton nmr , analytical chemistry (journal) , nmr spectra database , metabolomics , chemometrics , heteronuclear molecule , chemical shift , nuclear magnetic resonance , spectral line , chromatography , stereochemistry , physics , botany , quantum mechanics , astronomy , biology
NMR is a fast method for obtaining a holistic snapshot of the metabolome and also offers quantitative information without separating the compounds present in a complex mixture. Identification of the metabolites present in a plant extract sample is a crucial step for all plant metabolomics studies. In the present work, we used various two dimensional (2D) NMR methods such as J ‐resolved NMR, total correlation spectroscopy (TOCSY), and heteronuclear single quantum coherence sensitivity enhanced NMR spectroscopy for the identification of 36 common metabolites present in Coriandrum sativum L . seed extract. The identified metabolites belong to the following classes: organic acids, amino acids, and carbohydrates. 1 H NMR spectra of such complex mixtures in general display tremendous signal overlap due to the presence of a large number of metabolites with closely resonating multiplet signals. This signal overlapping leads to ambiguity in an assignment, and hence, identification of metabolites becomes tedious or impossible in many cases. Therefore, the utility of pure‐shift proton spectrum along the indirect ( F 1 ) dimension of the F 1 ‐PSYCHE‐TOCSY spectrum is demonstrated for overcoming ambiguity in assignment of metabolites in crowded spectral regions from Coriandrum sativum L . seed extract sample. Because pure‐shift NMR methods yield ultrahigh resolution spectrum (i.e., a singlet peak per chemical site) along one or more dimensions, such spectra provide better identification of metabolites compared with regular 2D TOCSY where signal overlap and peak distortions lead to ambiguity in the assignment. Nine metabolites were unambiguously assigned by pure‐shift F 1 ‐PSYCHE‐TOCSY spectrum, which was unresolved in regular TOCSY spectrum.