• Korean Journal of Pharmacognosy
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• v.44 no.2
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• pp.168-175
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• 2013

Aldose reductase (AR) plays a central role in the development of the diabetic complications. Eighty one Korean herbal medicines have been investigated for inhibitory activities on AR. Among them, fourteen herbal medicines exhibited a significant inhibitory activity compared with 3,3-tetramethyleneglutaric acid (TMG) as positive control. Particularly, Xanthium strumarium (fruit, whole plant), Ilex cornuta (stem and leaf), Vitex rotundifolia(stem), Sophora flavescens (whole plant), Platycarya stobilacea (flower) showed two times more potent inhibitory activity than 3,3-tetramethyleneglutaric acid (TMG).

• Korean Journal of Pharmacognosy
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• v.45 no.4
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• pp.359-365
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• 2014

Aldose reductase (AR) is the key enzyme of the polyol pathway in the development of the diabetic complications. Sixty seven Chinese herbal medicines have been investigated for inhibitory activities on AR. Among them, 7 herbal medicines, Buddleja crispa (twigs and leaves), Taiwania flousiana (twigs and leaves), Sloanea hemsleyana (fruits), Euphorbia nemetocypha (whole plants), Photinia glomerata (twigs and leaves), Vitex yunnanensis (twigs and leaves) exhibited a significant inhibitory activity against AR. Particularly, S. hemsleyana and V. yunnanensis showed 1.2-4.5 times more potent inhibitory activity than the positive control, 3,3-tetramethyleneglutaric acid (TMG).

• Journal of Applied Biological Chemistry
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• v.60 no.1
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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.

• Advances in Traditional Medicine
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• v.9 no.3
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• pp.245-251
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• 2009

Aldose reductase (AR) has been reported to play an important role in sugar-induced cataract. In the present study, the AR inhibitory activity of Enicostemma hyssopifolium (EH), Gymnema sylvestre, Eclipta alba, and Tinospora cordifolia (TC) were studied along with their effect on sugar-induced cataractogenic changes in sheep lenses in vitro. AR inhibitory activity of the aqueous extracts of plants and their anticataract potentials were evaluated in vitro in sheep lenses, considering the activity of normal sheep lenses as 100%. The concentration of the plant extract that showed maximum activity was selected to further study its effect on galactose-induced polyol accumulation in vitro. The $IC_50$ values of EH and TC were calculated to be 102 and 85 ${\mu}g$/ml, respectively. EH showed a significant inhibition (61.3%) in polyol accumulation followed by TC (53.1%). EH and TC possesses a significant anticataract activity in vitro and its anticataract potential could be related with its AR inhibitory effect.

• Korean Journal of Pharmacognosy
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• v.39 no.4
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• pp.324-329
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• 2008

Aldose reductase (AR), the key enzyme in the polyol pathway, plays an important role in the pathogenesis of diabetic complications such as cataract formation. AR inhibitors (ARI) can prevent or reverse early abnormalities in diabetic complications. However, none of ARI has achieved worldwide use because of limited efficacy or undesirable side effects. Therefore, evaluating natural sources for ARI potential may lead to the development of safer and more effective agents against diabetic complications. 49 Vietnam herbal medicines have been investigated with an in vitro evaluation system using aldose reductase inhibitory activities. Of these, 7 herbal medicines, Artemisia annua (leaf, stem), Duranta repens (leaf, stem), Excoecaria cochinchinensis (aerial part), Flueggea virosa (leaf, stem), Khaya senegalensis (leaf), Polygonum orientale (aerial part), Toxicodendron succedanea (leaf, stem) exhibited a significant inhibitory activity against aldose reductase. Particularly, Duranta repens (leaf, stem) and Toxicodendron succedanea (leaf, stem) showed two times more potent inhibitory activity than the positive control, 3.3-tetramethyleneglutaric acid (TMG).

• Korean Journal of Pharmacognosy
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• v.39 no.3
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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.

• Natural Product Sciences
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• v.12 no.4
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• pp.210-213
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• 2006

A 4,5-dioxoaporphine type alkaloid, cepharadione B (1), a phenolic acid, protocatechuic acid (2), and flavonols, quercetin (3), afzelin (4), and quercitrin (5), were isolated from the EtOAc-soluble extract of the whole plants of Houttuynia cordata. All the isolates (1-5) were subjected to in vitro bioassays to evaluate advanced glycation end products (AGEs) formation and rat lens aldose reductase (RLAR) inhibitory activity. The three flavonols 3-5 exhibited a significant inhibitory activity on AGEs formation with $IC_{50}$ values of 66.9, 58.9, and $32.3{\mu}M$, respectively. While the two flavonol rhamnosides 4 and 5 showed a remarkable inhibitory activity against RLAR with $IC_{50}$ values of 0.81 and $0.16{\mu}M$, respectively.

• Preventive Nutrition and Food Science
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• v.6 no.1
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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.

• Archives of Pharmacal Research
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• v.29 no.6
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• pp.479-483
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• 2006

Eight compounds were isolated from the fruiting bodies of Ganoderma applanatum, and were identified as 2-methoxyfatty acids (1), 5-dihydroergosterol (2), ergosterol peroxide (3) $3{\beta},7{\beta},20,23{\zeta}-tetrahydroxy-11,15-dioxolanosta-8-en-26-oic$ acid (4), $7{\beta},20,23{\zeta}-trihydroxy-3,11,15-trioxolanosta-8-en-26-oic$ acid (5), cerevisterol (6), $7{\beta},23{\zeta}-dihydroxy-3,11,15-trioxolanosta-8,20E(22)-dien-26-oic$ acid (7), and $7{\beta}-hydroxy-3,11,15,23-tetraoxolanosta-8,20E(22)-dien-26-oic$ acid methyl ester (8) by spectral analysis. All compounds were isolated for the first time from this fruiting bodies, and their effect on rat lens aldose reductase (RLAR) activity was tested. Among these eight compounds, ergosterol peroxide (3) was found to exhibit potent RLAR inhibition, its $IC_{50}$ value being $15.4\;{\mu}g/mL$.

• Journal of Applied Biological Chemistry
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• v.49 no.1
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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.