Mass spectrometric methods for the determination of flavonoids in biological samples

Regioselectivity of human UDP-glucuronosyl-transferase 1A1 in the synthesis of flavonoid glucuronides determined by metal complexation and tandem mass spectrometry

“…Flavonoids lacking a 3= hydroxyl group were glucuronidated only at position 7, while those containing this functionality also formed 3=-O-glucuronides and sometimes 4=-O-glucuronides, thus supporting the conclusion that the presence or absence of the 3=-OH group is the major determinant of the regioselectivity of glucuronidation. Moreover, the specific distribution of multiple glucuronide products ( The currently accepted paradigm involves the consumption of flavonoid glycosides in plant-based food products, deglucosylation in the small intestine by ␤-glucosidase or lactose phloridzin hydrolase, and rapid metabolism by Phase I and (especially) Phase II enzymes [1][2][3]. Glucuronidation and sulfation are important metabolic routes for most flavonoids, while methylation or hydroxylation may also occur depending on the structure of the molecule in question [2,3].…”

“…Early reports of unmodified flavonoid glycosides circulating in the bloodstream [9 -11] were likely mistaken identifications of flavonoid glucuronides, which have similar chromatographic and ultraviolet (UV) spectroscopic characteristics [7,12]. Flavonoids that fail to be absorbed in the small intestine may be broken down by microflora in the large intestine [1][2][3]. This process may release the free aglycons, which can then be absorbed and metabolized, but mostly results in the release of small phenolic acids, which are expelled in the urine [1][2][3].…”

A study of isomeric diglycosyl flavonoids by SORI CID of fourier transform ion cyclotron mass spectrometry in negative ion mode

“…Most of the previous papers have elucidated the structures of flavonoids based on lowresolution mass data, including the differentiation of flavonoid isomers [10,11] and multiglycosyl flavonoid structures [12,13]. Because most glycosyl flavonoids consist of C, H, O elements only, sometimes the analysis of the fragmentation pathways and the structures have been inconclusive based on low-resolution data, for example with an ion trap mass spectrometer [14]. March et al employed high-resolution and exact mass/ charge measurements of flavonoids by using Q-TOF mass spectrometry [15].…”

Recent developments in qualitative and quantitative analysis of phytochemical constituents and their metabolites using liquid chromatography–mass spectrometry

“…Because of their high medicinal significance such as anti-inflammatory, anti-hepatotoxic, estrogenic and cardio-protective properties, flavonoids have been receiving considerable attention. A series of reviews described separation and detection methods for flavonoids [64][65][66][67][68]. LC-UV-MS plays an important role in the screening of phenols and flavonoids.…”

“…Moreover, new metabolites generated during metabolism can possess unknown properties. For these reasons, careful examination of metabolites in biological systems is required [55,64]. Guo et al investigated phase I metabolites of isoliquiritigenin (2 ,4 ,4 -trihydroxychalcone) using human liver microsomes on a Q-TOF hybrid mass spectrometer (Waters Micromass Q-TOF-2) [100].…”