• Natural Product Sciences
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• v.22 no.2
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• pp.102-106
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• 2016

A methanolic extract of Corydalis ternata having aldose reductase inhibitory activity was examined as a possible aldose reductase (ALR2) inhibitor, a key enzyme involved in diabetic complications. Seven alkaloids, tetrahydrocoptisine (1), corydaline (2), tetrahydropalmatine (3), isocorybulbine (4), corybulbine (5), dehydrocorydaline (6), and N-methyltetrahydroberbinium (7) were isolated from $CHCl_3$ fraction of C. ternata methanol extract. Among them, compounds 1, 5, and 7 exhibited $5.04{\pm}1.97%$, $5.00{\pm}1.26%$, and $1.80{\pm}2.33%$ inhibitions, respectively at $40{\mu}M$. The activities of the single compounds were not comparable to that of the whole extract, suggesting that the whole combination of each single compound was responsible for the activity of the extract as shown in many cases of natural medicines. Even though this is the second report on aldose reductase inhibition activity of C. ternata, recombinant human aldose reductase was employed in this study unlike in the previous report. Furthermore, the aldose reductase inhibitory activities of isocorybulbine, corybulbine, and N-methyltetrahydroberbinium, to the best of our knowledge, were evaluated for the first time in this study. These results suggest a use of the extract of C. ternata for ameliorating diabetic complications.

• Korean Journal of Medicinal Crop Science
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• v.18 no.5
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• pp.305-310
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• 2010

Taxifolin-3-O-$\beta$-D-xylopyranoside and quercetin-3-O-$\alpha$-L-rhamnopyranoside were isolated from an EtOAc-soluble extract of the leaves of Chamaecyparis obtuse. Quercetin-3-O-$\alpha$-L-rhamnopyranoside was found to possess a potent inhibitory activity of human recombinant aldose reductase in vitro, its $IC_{50}$ value being $11.5\;{\mu}M$. Kinetic analysis showed that quercetin-3-O-$\alpha$-L-rhamnopyranoside exhibited uncompetitive inhibition against DL-glyceraldehyde. Also, quercetin-3-O-$\alpha$-L-rhamnopyranoside suppresses sorbitol accumulation in rat lens under high glucose conditions, demonstrating the potential to prevent sorbitol accumulation in vivo. These results suggest that this compound may be a promising agent in the prevention or treatment of diabetic complications.

• BMB Reports
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• v.43 no.4
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• pp.268-272
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• 2010

Aldo-keto reductase family 1 B10 (AKR1B10) is a member of the NADPH-dependent aldo-keto reductase (AKR) superfamily, and has been considered to be a potential cancer therapeutic target. Total extract from the bark of Rhus verniciflua (Toxicodendron vernicifluum (Stokes)) showed AKR1B10 inhibitory activity. To identify the active compounds from R. verniciflua responsible for AKR1B10 inhibition, nine compounds were isolated via bioactivity-guided isolation and tested for their effects against recombinant human AKR1B10 (rhAKR1B10). Results showed that butein, isolated from the ethyl acetate fraction, was most able to inhibit rhAKR1B10. The inhibitory rate of butein against rhAKR1B10 was 42.86% at $1\;{\mu}M$ with an IC50 value of $1.47\;{\mu}M$, and enzyme kinetic analysis revealed its inhibition mode to be uncompetitive.

• Journal of Applied Biological Chemistry
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• v.52 no.4
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• pp.216-220
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• 2009

Aldo-keto reductase family 1 B10 (AKR1B10) has been considered as a potential cancer therapeutic target. Ethanol extracts prepared from 82 Korean local plants were examined for their antioxidant activity and inhibitory effects on recombinant human AKR1B10 (rhAKR1B10) in vitro. 21 extracts showed more than 80% of ABTS radical scavenging activity at $100\;{\mu}g/mL$ and 11 extracts inhibited more than 50% of rhAKR1B10 activity at $10\;{\mu}g/mL$. Especially, 9 extracts showed potent inhibition on rhAKR1B10 activity compared with positive control tetramethylene glutaric acid.

• Korean Journal of Pharmacognosy
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• v.40 no.3
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• pp.238-243
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• 2009

We examined ethanol extracts prepared from 23 Korean local plants obtained in Pyeongchang, Gangwon-do for their inhibitory effects on recombinant human AKR 1 B10 (rhAKR1B10) in vitro. To do this, rhAKR1B10 was first expressed in E. coli as a biological active form and purified by using Ni-affinity chromatography followed by gel permeation chromatography. Then, rhAKR1B10 was used for screening out 23 Korean local plant extracts having an inhibitory activity against itself. Among them, six extracts showed more than 50% inhibition of rhAKR1B10 activity at the concentration of $10{\mu}g$/ml. Especially, the extracts of Ligularia fischeri var. spiciformis Nakai and Rhus trichocarpa Miq. were the most potent because their $IC_{50}$ values were 2.94 and $2.00{\mu}g$/ml, respectively.