Herbal extracts inhibit Maillard reaction, and reduce chronic diabetic complications risk in streptozotocin-induced diabetic rats

Objectives: Accumulation of end-stage products of the Maillard reaction, also called advanced glycation end products (AGEs), is a hallmark of aging and the pathogenesis of chronic diabetic complications. The aim of this study was to determine whether safe and effective substances contained in four extracts of foodstuffs might slow the development of diabetic complications as well as slow the progression of aging.Design: We evaluated the in-vitro activity of four extracts of dried herbs available in Japan (Anthemis nobilis, Crataegus oxyacantha, Houttuynia coradata, Vitis vinifera) and a mixture of these to inhibit the Maillard reaction. We also assessed whether a 12-week feeding of mixed herbal extract (MHE) admixed in MF chow to streptozotocin (STZ)-induced diabetic rats prevented the development of diabetic complications.Results: Each of the four herbal extracts as well as the mixed extract dose-dependently inhibited the generation of Maillard reaction products in vitro with a potency similar to that of aminoguanidine (AG), a drug used for treating diabetic complications. Furthermore, after a 12-week, MHE supplemental feeding to STZ-induced diabetic rats, serum pentosidine and Ne-(carboxymethyl)lysine levels and wet weight of the kidney tended to decrease. MHE elicited AG-like actions and produced an inhibitory effect on pentosidine generation at lower concentrations than those observed for AG.Conclusion: Through the inhibition of the Maillard reaction, MHE may slow the development of chronic diabetic complications as well as slow the progression of aging.