Inhibitory effect of glucodistylin from the bark of Quercus acutissima on human recombinant aldose reductase and sorbitol accumulation

Center for Efficacy Assessment and Development of Functional Foods and Drugs, Hallym University, Chuncheon, Korea.
Archives of Pharmacal Research (Impact Factor: 2.05). 02/2011; 34(2):211-5. DOI: 10.1007/s12272-011-0205-1
Source: PubMed


A flavanol glycoside, glucodistylin (1) and three polyphenol derivatives, gallate (2), (+)-catechin (3) and (+)-gallocatechin (4) were isolated from an aqueous acetone extract of the bark of Quercus acutissima. Of these compounds, glucodistylin exhibited uncompetitive inhibitory activity against recombinant human aldose reductase with an IC(50) value of 7.2 μM. Furthermore, glucodistylin inhibited sorbitol accumulation by 48.84% at 50 μM. This flavonoid showed therapeutic potential in the prevention and treatment of diabetes-related complications.

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    ABSTRACT: We evaluated the inhibitory effects of extracts and components of Geranium thunbergii on aldose reductase (AR) and galactitol formation in rat lenses with high levels of galactose as a part of our ongoing search of natural sources for therapeutic and preventive agents for diabetic complications. The inhibitory effects of water, methanol and ethanol extracts of G. thunbergii on rat lens AR (RLAR) were determined. Comparing inhibitory effects of various solvent extracts, ethanol extract showed RLAR inhibitory activity ( values, 5.24 and , respectively). The ethanol extract was fractionated to chloroform, ethyl acetate and water. Of these, the ethyl acetate fraction from ethanol extract of G. thunbergii exhibited RLAR inhibitory activity ( value, ). In order to identify the bioactive components of ethyl acetate soluble fraction of ethanol extract from G. thunbergii, eight compounds, namely gallic acid (1), protocatechuic acid (2), p-hydroxybenzoic acid (3), brevifolin carboxylic acid (4), geraniin (5), ellagic acid (6), kaempferol-3-O-arabinofuranosyl-7-O-rhamnopyranoside (7), kaempferitrin (8) were isolated. The isolates were subjected to in vitro bioassays to evaluate their inhibitory activity on RLAR and galactitol formation in rat lenses. The ellagic tannins (5, 6) and flavonoid (7) exhibited strong inhibitory effects on RLAR. Also, these three compounds (5, 6 and 7) suppressed galactitol accumulation in rat lens under high galactose conditions, demonstrating the potential to prevent galactitol accumulation exo vivo. These results suggest that the extracts and components of G. thunbergii are a promising agent in the prevention or treatment of diabetic complications.
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