Methylglyoxal: its presence and potential scavengers

Hyperglycemia is the most important factor for the onset and progress of diabetic complications. A growing body of evidence indicates that the increase in reactive carbonyl intermediates such as methylglyoxal (MG) is a consequence of hyperglycemia in diabetes. Several studies have shown that higher levels of MG are present in diabetic patients' plasma compared to non-diabetics. Glyoxal (GO) and MG, the two major alpha-dicarbonyl compounds found in humans, are very reactive and lead to nonenzymatic glycation in vivo. Glycation is a complex series of reactions between reducing sugars and amino compounds, and it will lead to the formation of advanced glycation end products (AGEs). AGEs and dicarbonyl species are both linked to possible clinical significance in chronic and age-related diseases. It is well-known that tea is rich in polyphenolic compounds and that it has potential health benefits, including the prevention of diabetes. We have shown in a previous study that all tea polyphenols have very good MG trapping abilities. In this study, using time course, we have further indicated that one molecule form black tea, theaflavins-3,3'-digallate, can trap two molecules of MG under simulated physiological conditions. In addition, we have discovered that commercial carbonated beverages contain extremely high levels of MG. The potential hazardous effects of dietary MG on humans remain to be explored.