2-Deoxyglucosone: A New C₆-α-Dicarbonyl Compound in the Maillard Reaction of d-Fructose with γ-Aminobutyric Acid

Abstract

In this study, α-dicarbonyl compounds consisting of a backbone with six carbon atoms resulting from the Maillard reaction of D-fructose with γ-aminobutyric acid were determined. The reaction was carried out under mild reaction conditions at 50 °C and water contents between 0 and 90%. A thus far unknown α-dicarbonyl compound was found as the main product in the first 24 h at water contents below 50%. After isolation of its stable quinoxaline derivative, it was possible to identify the compound as 2-deoxy-D-glycero-hexo-3,4-diulose (2-deoxyglucosone). For the first time, the four C 6 -α-dicarbonyl compounds, 1-deoxyglucosone, 2-deoxyglucosone, 3-deoxyglucosone, and 4-deoxyglucosone, could be identified in the Maillard reaction of a hexose at the same time. This indicates the formation of a 2,3-eneaminol from the Schiff base of D-fructose and the formation of 2-amino-2-deoxy-3-ketose as an alternative to the Heyns product.

Pathways of Non-enzymatic Lysine Acylation

“…Last but not least, α-dicarbonyls are important precursors of non-enzymatic lysine acylation in the context of glycation leading to formation of amide advanced glycation endproducts (amide AGEs) ( Henning et al, 2011 ; Henning and Glomb, 2016 ). A class of reactive α-dicarbonyls called deoxyglucosones is generated as intermediates in the Maillard reaction ( Bruhns et al, 2018 ). The best studied structures of this class are 3-deoxyglucosone (3-DG), 1-deoxyglucosone (1-DG), and glucosone.…”

Isotope-Coding Derivatization for Quantitative Profiling of Reactive α-Dicarbonyl Species in Processed Botanicals by Liquid Chromatography–Tandem Mass Spectrometry

“…For analyzing real samples, a new sample workup was adopted to cover a broad analyte–matrix combination for α-DCs in dried botanicals. This generic pretreatment for analyte extraction and/or matrix removal − , involves nonoxidizing deproteinization with formic acidified acetonitrile, CEPS-based aqueous acetonitrile extraction/cleanup and a straightforward DFI protocol. Apart from efficient denaturation (precipitation) of matrix proteins under mild conditions, acetonitrile is often selected as the flexible solvent of choice to extract multiclass chemicals from various sample matrices. , Also, the water-miscible acetonitrile in aqueous solutions can be handily phase-separated by adding electrolytes (salts, sugars, and polymers) or by cooling to subzero temperatures, which is well compatible with the conventional reverse-phase LC–MS analysis.…”

“…The matrix-induced effect is a major concern in LC–ESI-MS bioanalysis, particularly those requiring chemical derivatizations which contain an excess of the derivatizing reagent, buffer salts, and other auxiliary additives. ,, Apart from matrix removal by thorough cleanup, sample dilution with a blank solvent is gaining interest as an alternative option to reduce or eliminate MEs. Recently, we have shown that a dilution factor of 20–60 may significantly reduce MEs from the clarified extracts, but higher dilution factors (>500-fold) are required to counteract the severe matrix interference by the direct injection of the diluted sample extracts without additional cleanup treatment. , In the present workflow, an absolute amount of 0.5 g of dry material was extracted with 10 mL of acidified acetonitrile–water mixture, and the crude extract was diluted 2.5-fold for OPD derivatization; and then the reaction mixture was processed by the CEPS/DFI treatment with a further 2.6-fold dilution of the clear filtrate before injection into the LC–MS/MS system. Thus, the combination of the one-pot labeling and CEPS/DFI processing yields an extensive dilution of raw samples by a factor of 130, corresponding to approximately 3.9 mg/mL (i.e., 1/130 × 0.5 g/mL) of the coextracted matrix equivalent in the final injection solution, which resulted in consistent low MEs (within ± 20%) for all the analyte/matrix pairs without excessively sacrificing sensitivity (Table ).…”

“…Hitherto, a total of nearly 30 different α-DCs (Table ) have been discovered from Maillard-like reactions, ,− including but not limited to the major and frequently detected α-oxoaldehydes GO, MGO, and 3DG. To expand the analyte coverage, we used a long-gradient UHPLC elution program to obtain a broad distribution of α-DC-derived quinoxalines with C 2 –C 12 skeletons across the whole chromatographic space . A diverter valve was used to prevent the unwanted contamination of the early eluting OPD reagent (2–3 min) and highly (non)­polar components away from the MS detector.…”

Pyrraline formation prevented by sodium chloride encapsulated by binary blends of different starches and gum Arabic in aqueous model systems and cookies

“…One is that the reducing sugar reacts with an amino group to form the Schiff base. Then, a 1,2enolization, a vinylogous b-elimination of the hydroxy group attached to carbon C3 and the hydrolysis of the amino acid occurred (Bruhns et al, 2018). Another is that 3-DG has been regarded as being the product of a side reaction of the Lobry de Bruyn-Alberda van Ekenstein Transformation from carbohydrates without amine participation (Anet, 1964).…”