DescriptionThe importance of reactive dicarbonyl speices has been raising because of its link to many health complications. Diabetes, with the high prevalence and continued investigation on its link to methylglyoxal interested us to initiate this study. We believe that MG is involved in a vicious circle in which the elevated methylglyoxal is caused by the hyperglycemic condition and also by the consequent oxdative stress. On the other hand, the increase of methylglyoxal and oxidative stress deplete antioxidative system including glutathione and its related enzymes. This will then not only worsen the oxidative stress, but also change the route of glycolysis and other metabolisms, ketone body, fructose, etc. The vicious circle is thus turned on. We, therefore, state here that controlling the intra and extra sources and causes of methylglyoxal is of significance.
Our study first established the reliable and sensitive analytical methods for methylglyoxal determination. The combinations of proper derivatization reagents for methylglyoxal and analytical methods, GC or HPLC have been examined. Secondly, we have investigated the methylglyoxal trapping efficiency and mechanisms of dietary compounds. The kinetic studies were carried out and reaction products were characterized by LC/MS.
Tea polyphenol compounds, firstly, have shown the potential health benefits in many aspects including prevention diabetes which has the impact with methylglyoxal and methylglyoxal related AGEs. They did show the excellent trapping activity of methylglyoxal. The kinetic study and identification of EGCG-methylglyoxal products provides the preliminary understanding of the trapping mechanism by tea.
The second group, dipeptides and tripeptides, are having higher bioavailability compared to tea polyphenol compounds. The chosen dipeptides may trap methylglyoxal via formation of pyrazinone or S-(carboxyethyl)cysteine derivatives. With different side chain, most dipeptides represented different reactivity to methylglyoxal and kinetic trends. Moreover, the difference observed between triglycine and diglycine, and the one between Gly-Cys and Cys-Gly make the studying of mechanisms more essential. This varied reactivity combined with the high bioavailability, peptides may be potent to target the methylglyoxal generated at different conditions. Further consideration of their bioavailability and kinetic trends may provide the diverged and useful ways to trap methylglyoxal in vitro or in vivo.