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Trapping reactions of reactive carbonyl species with tea polyphenols in simulated physiological conditions
Author(s) -
Lo ChihYu,
Li Shiming,
Tan Di,
Pan MinHsiung,
Sang Shengmin,
Ho ChiTang
Publication year - 2006
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200600094
Subject(s) - methylglyoxal , chemistry , glycation , derivatization , polyphenol , maillard reaction , glyoxal , chromatography , gallate , organic chemistry , nuclear chemistry , high performance liquid chromatography , biochemistry , enzyme , antioxidant , receptor
The carbonyl stress that leads to the formation of advanced glycation end products (AGEs) in diabetes mellitus has drawn much attention recently. Reactive alpha‐dicarbonyl compounds, such as glyoxal (GO) and methylglyoxal (MGO), have been shown to be a high potential glycation agent in vitro and in vivo . In this study, epicatechins in green tea and theaflavins in black tea were found to be able to reduce the concentration of MGO in physiological phosphate buffer conditions. Modified MGO derivatization for GC/flame ionization detector (FID) method in quantification was systematically conducted. In molar ratio of 3 (MGO/polyphenol), theaflavin‐3,3′‐digallate (TF3) in theaflavins and (–)‐epigallocatechin (EGC) in epicatechins showed the highest MGO reduction at 66.65 and 45.74%, respectively, after 1 h of incubation. In kinetic study (molar ratio of MGO/polyphenol = 1:1), rapid MGO reduction occurred within 10 min. Identities of primary adducts between (–)‐epigallocatechin gallate (EGCG) and MGO were determined. Newly generated stereoisomers at the C8 position of EGCG A‐ring were isolated with a chiral column, and structurally confirmed by 2‐D NMR analyses.