Reduction of 3-Deoxyglucosone by Epigallocatechin Gallate Results Partially from an Addition Reaction: The Possible Mechanism of Decreased 5-Hydroxymethylfurfural in Epigallocatechin Gallate-Treated Black Garlic

Abstract

5-Hydroxymethylfurfural (5-HMF) is a harmful substance generated during the processing of black garlic. Our previous research demonstrated that impregnation of black garlic with epigallocatechin gallate (EGCG) could reduce the formation of 5-HMF. However, there is still a lack of relevant research on the mechanism and structural identification of EGCG inhibiting the production of 5-HMF. In this study, an intermediate product of 5-HMF, 3-deoxyglucosone (3-DG), was found to be decreased in black garlic during the aging process, and impregnation with EGCG for 24 h further reduced the formation of 3-DG by approximately 60% in black garlic compared with that in the untreated control. The aging-mimicking reaction system of 3-DG + EGCG was employed to determine whether the reduction of 3-DG was the underlying mechanism of decreased 5-HMF formation in EGCG-treated black garlic. The results showed that EGCG accelerated the decrease of 3-DG and further attenuated 5-HMF formation, which may be caused by an additional reaction with 3-DG, as evidenced by LC-MS/MS analysis. In conclusion, this study provides new insights regarding the role of EGCG in blocking 5-HMF formation.

Reactive Carbonyl Species Scavenger: Epigallocatechin-3-Gallate

“…For instance, in the xylose-alanine model, EGCG, as a nucleophilic reagent, undergoes electrophilic aromatic substitution reactions at the C6 or C8 sites of the A-ring with Amadori rearrangement products (ARP) or deoxypentosone (DP) to form ARP-EGCG and ARP-DP-EGCG adducts [82]. In the black garlic model, black garlic immersed in EGCG was able to bind to the Maillard reaction intermediates such as HMF and 3-DG, reducing the level of active carbonyl compound precursors and further inhibiting the generation of active carbonyl compounds [85].…”