Quantum mechanical qHNMR metabolomic standardization of Glycyrrhiza glabra and Humulus lupulus preparations

Abstract

Unlike other methods, NMR is a bivalent botanical standardization method: it combines the identification of multiple marker compounds with their simultaneous quantitation, all in a single analysis. The goal of this internship project is to learn a new qHNMR quantification method that fits NMR resonance profiles with quantum mechanical calculations. This approach is highly complementary to Natural Products (NPs) metabolomic analysis, because the 1H NMR spectra are complex systems with many overlapping signals. In order to resolve this complexity, quantum mechanical (QM) calculations can be performed, e.g. by PERCH and CT software. These calculations utilize quantitative 1H NMR building block spectra of isolated compounds present in the sample to ultimately achieve quantification. For this purpose, the building block spectra are used to create simulated, fitted spectrum which will be compared to the experimental spectra for quantification. From the comparison of both, QM-simulated and experimental spectra, it is possible to accurately quantify compounds even in highly overlapped areas of a given NMR spectrum. Therefore, the project proposal aims to develop a QM-qHNMR model that is based on the concept of building blocks in quantitative 1H NMR using the spectra of 25 isolated prenylchalcones, flavonoids, and isoflavones that are characteristic for Glycyrrhiza glabra and Humulus lupulus and can be used for the quantification of their botanical products. The reference compounds and plant extracts, as well as the required NMR instrumentation and software are all available at UIC and are a unique asset for achieving the research and training goal. The proposed project is an excellent fit for the ongoing project #2018-00504-2 in Brazil, as they share key aspects of metabolomic NPs analysis. Moreover, this internship program will provide the candidate with a solid, advanced, and unparalleled training in an area of NMR spectroscopy applied to quantitative NMR (qNMR). (AU)