title: Evolution of Quantitative Measures in NMR: Quantum Mechanical qHNMR Advances Chemical Standardization of a Red Clover (Trifolium pratense) Extract.
abstract: Chemical standardization, along with morphological and DNA analysis ensures the authenticity and advances the integrity evaluation of botanical preparations. Achievement of a more comprehensive, metabolomic standardization requires simultaneous quantitation of multiple marker compounds. Employing quantitative1H NMR (qHNMR), this study determined the total isoflavone content (TIfCo; 34.5-36.5% w/w) via multimarker standardization and assessed the stability of a 10-year-old isoflavone-enriched red clover extract (RCE). Eleven markers (nine isoflavones, two flavonols) were targeted simultaneously, and outcomes were compared with LC-based standardization. Two advanced quantitative measures in qHNMR were applied to derive quantities from complex and/or overlapping resonances: a quantum mechanical (QM) method (QM-qHNMR) that employs1H iterative full spin analysis, and a non-QM method that uses linear peak fitting algorithms (PF-qHNMR). A 10 min UHPLC-UV method provided auxiliary orthogonal quantitation. This is the first systematic evaluation of QM and non-QM deconvolution as qHNMR quantitation measures. It demonstrates that QM-qHNMR can account successfully for the complexity of1H NMR spectra of individual analytes and how QM-qHNMR can be built for mixtures such as botanical extracts. The contents of the main bioactive markers were in good agreement with earlier HPLC-UV results, demonstrating the chemical stability of the RCE. QM-qHNMR advances chemical standardization by its inherent QM accuracy and the use of universal calibrants, avoiding the impractical need for identical reference materials.
authors.forename: Rasika S
authors.initials: RS
authors.lastname: Phansalkar
authors.forename: Charlotte
authors.initials: C
authors.lastname: Simmler
authors.forename: Jonathan
authors.initials: J
authors.lastname: Bisson
authors.forename: Shao-Nong
authors.identifier: 0000-0003-0748-0863
authors.initials: SN
authors.lastname: Chen
authors.forename: David C
authors.initials: DC
authors.lastname: Lankin
authors.forename: James B
authors.initials: JB
authors.lastname: McAlpine
authors.affiliation: PERCH Solutions Ltd. , Puijonkatu 24 B 5, 70110 Kuopio, Finland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Niemitz
authors.forename: Guido F
authors.identifier: 0000-0003-1022-4326
authors.initials: GF
authors.lastname: Pauli
mesh_terms: D002851:Chromatography, High Pressure Liquid; D007529:Isoflavones / Q000032:analysis*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D012015:Reference Standards; D029921:Trifolium / Q000737:chemistry*
chemical_list: D007529:Isoflavones