Flavonoid glycosides from the leaves of Uvaria rufa with advanced glycation end-products inhibitory activity

Abstract

Prolonged hyperglycemia in diabetic patients leads to the formation of advanced glycation end-products (AGEs) in their body tissues, which contribute to the development and progression of diabetic complications and aging. Preliminary screening of the ethyl acetate extract of the leaves of Uvaria rufa Blume (family Annonaceae) indicated its AGEs inhibitory activity. Fractionation of the extract yielded five flavonol glycosides including rutin (1) isoquercitrin (2), kaempferol 3-O-β-D-galactopyranoside (3), astragalin (4), and isoquercitrin-6-acetate (5). Isoquercitrin and its 6-acetate derivative were comparable with the positive control, quercetin, in their ability to inhibit the formation of AGEs in the bovine serum albumin (BSA)-glucose assay, having the 50% inhibitory concentrations (ICs50) of 8.4, 6.9 and 10.9 μM, respectively.