Fitoterapia
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Glycation, the nonenzymatic adduct formation between sugar dicarbonyls and proteins, is one key molecular basis of diabetic complications due to hyperglycemia. Given the link between glycation and oxidation, we hypothesized that herbal extracts with a high concentration of antioxidant phenolics might possess significant in vitro antiglycation activities as well. The aim of the present study was to address the hypothesis that polyphenol-rich Ilex paraguariensis (IP) extracts are capable of inhibiting advanced glycation end-products (AGEs) formation and to compare the potency of these extracts with green tea and with the standard antiglycation agent aminoguanidine. ⋯ The effect is therefore due mainly to an inhibition of the second phase of the glycation reactions, namely the free-radical mediated conversion of the Amadori products to AGE. Taken together our results demonstrate a significant, dose-dependent effect of water extracts of I. paraguensis on AGE adducts formation on a protein model in vitro, whereas green tea displays no significant effect. The inhibition of AGE formation was comparable to that obtained by using millimolar concentrations of the standard antiglycation agent aminoguanidine.