• Natural Product Sciences
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• 제10권1호
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• pp.35-39
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• 2004

Aldose reductase (AR), the key enzyme of the polyol pathway, is known to play important roles in the diabetic complications. The inhibitors of AR, therefore, would be potential agents for the prevention of diabetic complications. In order to clarify the structural requirements of flavonoids for aldose reductase inhibitory activity, thirty flavonoids were examined. Among the thirty flavonoids, flavonols such as quercetin (5), reyneutrin (7), quercitrin (9), isoquercitrin (11), and avicularin (14) were found to exhibit much stronger AR inhibition. Lonicerin (10), amentoflavone (27) and sophoraflavanone B (30) were also showed strong inhibitory activity. Especially, quercitrin and reyneutrin exhibited the most inhibitory potency on rat lens (RL) AR. The results suggested that flavonol having the 7-hydroxyl and/or catechol moiety at the B ring exhibit strong activity. In addition, flavonols having 3-O-monosaccharide also showed stronger inhibition than free flavonols at the 3-position. These results suggested that quercitrin and reyneutrin are attributed to be the promising compounds for the prevention and/or treatment of diabetic complications.

• 생약학회지
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• 제39권3호
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• pp.165-173
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• 2008

Aldose reductase (AR), the principal enzyme of the polyol pathway, has been shown to play an important role in the diabetic complications, including diabetic cataract. The inhibitors of AR, therefore, would be potential agents for prevention of diabetic complications. As part of our ongoing project directed toward the discovery of preventive and/or treatment for diabetic complications, 48 Korean herbal medicines have been investigated with an in vitro evaluation system using aldose reductase inhibitory activities. Of these, 12 herbal medicines exhibited a significant inhibitory activity against aldose reductase. Particularly, seven herbal medicines, i.e., Eurya japonica, Chrysanthemum indicum, Akebia quinata, Saururus chinensis, Catalpa bignonioides, Lonicera japonica, Vitex rotundifolia showed two times more potent inhibitory activity than the positive control 3.3-tetramethyleneglutaric acid (TMG). In addition, Catalpa bignonioides showed the retardation of cataract-opacification of the lens of the eye under diabetic condition by xylose. Therefore, this result may provide a potential therapeutic approach for preventing and treating diabetic cataracts.

• Preventive Nutrition and Food Science
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• 제6권1호
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• pp.38-42
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• 2001

The methanol extracts of 25 leguminous seeds in vitro were evaluated for inhibitory activities against lens aldose reductase of Sprague Dawley male rats. The responses varied with both leguminous seed and concentration used. At the concentration of 0.1 mg/mL, the methanol extracts from Amphicaraea edgeworthii, Canavalia lineata, Gylcine max var. solitae, Glycine max var. yagkong, Glycine max var. hooktae, Glycine max var. bangkong, Glycine max var. geumdu, Glycine max var. chungtae, Glycine max var. mejukong, Glycine soja, Phaseolus radiatus var. geodu, Vicia tetrasperma, Vigna angulasis, and Vigna sinensis inhibited enzyme activity by greatertha 60%. In following study, at the concentration of 0.01 mg/mL, the extracts of C. lineata and V. tetraspermahad relatively strong inhibitory activity against aldose reductase. Because of their potent inhibitory activities, the activity of each solvent fraction from C. lineata and V. tetrasperma was determined, and the potent activity was showed from chloroform and hexane fractions, respectively. {TEX}$IC_{50}${/TEX} values of C. lineata and V. tetrasperma were 0.004 and 0.006 mg/mL, respectively. As a naturally occurring therapeutic agent, leguminous seeds described could be useful for developing new agents of antidiabetic complications.

• Natural Product Sciences
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• 제17권3호
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• pp.230-233
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• 2011

To evaluate the potential of naturally occurring aldose reductase (AR) inhibitors from food material, MeOH extract and stepwise polarity fractions from tartary buckwheat and two common Korean buckwheat cultivars, yangjul-maemil and daesan-maemil, were tested on AR inhibition in rat lens in vitro. The EtOAc fraction from tartary buckwheat exhibited good AR inhibitory activity ($IC_{50}$ value, $8.19\;{\mu}g$/ml). A portion of the EtOAc fraction from tartary buckwheat led to the isolation of rutin by MeOH recrystalization. Rutin exhibited good AR inhibitory activity ($IC_{50}$ value, $9.28\;{\mu}M$). These results suggest that tartary buckwheat could be a useful food material in the development of a novel AR inhibitory agent against diabetic complications.

• Journal of Applied Biological Chemistry
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• 제49권1호
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• pp.24-27
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• 2006

Four ursane-type triterpenoids, 2${\alpha}$,3${\alpha}$,19${\alpha}$-trihydroxy-24-norurs-4(23),12-dien-28-oic acid (1), 4(R),23-epoxy-2${\alpha}$,3${\alpha}$,19${\alpha}$-trihydroxy-24-norurs-12-en-28-oic acid (2), myrianthic acid (3), and tormentic acid (4), and a phenolic compound, ethyl gallate (5), from an EtOAc-soluble extract of the stems of Rumex japonicus, were subjected to in vitro bioassays to evaluate advanced glycation end products (AGEs) and rat lens aldose reductase (RLAR) inhibitory activity. Compounds 1 and 5 exhibited a significant inhibitory activity on AGEs formation with $IC_{50}$ value of 87 ${\mu}M$ and on RLAR with $IC_{50}$ value of 14.3 ${\mu}M$, respectively. Ethyl gallate (5) was isolated for the first time from this plant.

• Natural Product Sciences
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• 제13권2호
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• pp.160-163
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• 2007

Four glycosides, rosamultin (1), tetracentronside B (2), 4-O-methylellagic acid 3-O-${\alpha}$-$_L$-rhamnopyranoside (3), and vanillic acid 4-O-${\beta}$-$_L$-glucopyranoside (4), isolated from the roots extract of Potentilla discolor, were subjected to in vitro bioassays to evaluate the inhibitory activity on advanced glycation end products (AGEs) formation and rat lens aldose reductase (RLAR). Compound 3 exhibited a significant inhibitory activity against both AGEs formation and RLAR with IC$_{50}$ values of 79.5 and 8.03 ${\mu}$M, respectively. All the compounds (1-4) were isolated for the first time from this plant.

• 농업과학연구
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• 제39권1호
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• pp.69-73
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• 2012

The purpose of this study was to evaluate the potential of naturally occurring aldose reductase (AR) inhibitors from white-color natural products (Aruncus dioicus var. kamtschaticus, Chionanthus retusa, Cosmos bipinnatus, Hibiscus syriacus, Hydrangea paniculata, Magnolia denudata, Prunus padus, Robinia pseudo-accacia, Rhododendron mucronulatum for. albiflorum, Spiraea blumei, and Spiraea prunifolia var. simpliciflora). The MeOH extract of white-color natural products were tested on rat lens AR inhibition in vitro. Among them, the MeOH extract of R. mucronulatum for. albiflorum showed highest inhibition on AR ($IC_{50}$ value, 1.07 ${\mu}g/ml$). These results suggested that R. mucronulatum for. albiflorum, a white-color natural product, could be a useful resource in the development of a novel AR inhibitory agent against diabetic complications.

• Journal of Applied Biological Chemistry
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• 제60권1호
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• pp.29-33
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• 2017

The methanol extract of Rhododendron mucronulatum for. albiflorum (RMFA) stems inhibited aldose reductase (AR) activity. The RMFA fractions obtained by stepwise extraction with solvents of different polarity were tested for AR inhibition in vitro using the lens of a rat. Among them, the ethyl acetate (EtOAc) fraction inhibited AR more than the other fractions. Quercetin (1) from the EtOAc fraction showed a high AR inhibition with $IC_{50}$ of $2.11{\mu}M$. The stems of RMFA contained the highest amount (5.12 mg/g extract) of quercetin. Our results suggest that RMFA, which contained quercetin, could be a useful material for the development of supplementary functional foods.

• 농업과학연구
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• 제40권1호
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• pp.47-51
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• 2013

To search for the aldose reductase (AR) inhibitors from Korean folk plants, the inhibition of rat lens AR in vitro using the methanol (MeOH) extracts from Korean folk plants in Chungcheong Province was investigated. Among Korean folk plants tested, the MeOH extract of Persicaria longiseta showed highest inhibition of AR ($IC_{50}$ value, $5.14{\mu}g/ml$). Consequently, P. longiseta has a possibility of new natural resources for the development of AR inhibitor for the prevention of diabetic complications.

• Archives of Pharmacal Research
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• 제18권2호
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• pp.65-68
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• 1995

The methanol extract from the whole parts of the flowers of Chrysanthemum boreals was found to exhibit a significant inhibition of a rat lens aldose reductase (RLAR) activity in vitro. Bioassay guided systematic fractionation of the methanol extract led to the isolation of four flavonoids which were identified as acacetin (1), apigenin (II), luteolin (III) and linarin (IV). Compounds I-III were demonstrated to exhibit a significant inhibition of RLAR. Luteolin (II) was found to be the most potent AR inhibitor with $IC_{50}$ value of $5{\times}10^{-7}M$.