Protective activity of flavonoid and flavonoid glycosides against glucose-mediated protein damage

The pathogenesis of diabetic vascular complications involves the formation of advanced glycation end-products (AGEs). AGEs accumulate slowly in the body with age and more rapidly in individuals with diabetes mellitus. An abnormally elevated blood glucose level in diabetes mellitus causes the formation of AGEs. Also, oxidative reactions contribute significantly to the formation of AGEs. The antioxidant flavonoids, quercetin, isoquercitrin, hyperin and cacticin from plants, decrease the formation of AGEs. This activity was examined using an in vitro glycation reaction. Of the tested compounds, isoquercitrin and hyperin showed a strong inhibitory activity against the formation of AGEs. These compounds showed inhibitory activities that were more potent than the positive control, aminoguanidine. These results suggest that isoquercitrin and hyperin may be promising agents to treat glycation-associated diseases. (C) 2010 Elsevier Ltd. All rights reserved.