文摘
Licorice botanicals are produced from the roots of Glycyrrhiza species (Fabaceae), encompassing metabolites of both plant and rhizobial origin. The composition in both primary and secondary metabolites (1掳/2掳Ms) reflects the physiologic state of the plant at harvest. Interestingly, the relative abundance of 1掳Ms vs 2掳Ms in licorice extracts remains undetermined. A centrifugal partition chromatography (CPC) method was developed to purify liquiritin derivatives that represent major bioactive 2掳Ms and to concentrate the polar 1掳Ms from the crude extract of Glycyrrhiza uralensis. One objective was to determine the purity of the generated reference materials by orthogonal UHPLC-UV/LC-MS and qHNMR analyses. The other objectives were to evaluate the presence of 1掳Ms in purified 2掳Ms and define their mass balance in a crude botanical extract. Whereas most impurities could be assigned to well-known 1掳Ms, p-hydroxybenzylmalonic acid, a new natural tyrosine analogue, was also identified. Additionally, in the most polar fraction, sucrose and proline represented 93% (w/w) of all qHNMR-quantified 1掳Ms. Compared to the 2掳Ms, accounting for 11.9% by UHPLC-UV, 1掳Ms quantified by qHNMR defined an additional 74.8% of G. uralensis extract. The combined orthogonal methods enable the mass balance characterization of licorice extracts and highlight the relevance of 1掳Ms, and accompanying metabolites, for botanical quality control.