Rutin derivatives as potent AGE inhibitors and its relevance in diabetes complications

Abstract

Glycation is a reversible, non‐enzymatic reaction between reducing sugars and amino groups of proteins that undergo rearrangements to stable ketoamines, which lead to the formation of advanced glycation end products (AGEs) such as fluorescent and non‐fluorescent ( N ε ‐ carboxymethyllysine, CML) protein adducts and protein crosslinks. Protein glycation, induced by hyperglycemia, has been implicated in the appearance of diabetic complications that involved kidney, eye and neuronal tissue damage. When aminoguanidine, a proven AGEs inhibitor, was tested as an anti‐diabetic drug in human clinical trials presented important side effects and this suggested a need for new and improved AGEs inhibitors. Histone H1 and ADP‐ribose were used as a model for protein glycation since it allow us to distinguish true AGE inhibitors from general antioxidants. Rutin derivatives were tested as AGEs inhibitors since rutin, a common dietary flavonoid that is consumed in fruits, vegetables and plant derived beverages, is not absorbed intact due to gut microflora degradation. Our data showed that 3,4‐dihydroxyphenylacetic acid and homovanillic acid were as powerful inhibitors of fluorescence, crosslinks and the formation of CML protein adducts as aminoguanidine. These results suggest effective natural product AGE inhibitors that might potentially be recommended as dietary supplements in diabetes complication prevention.