• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.124-129
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• 2016

The extraction and purification of the anti-hyperglycemic α-glucosidase inhibitor from an edible mushroom, Pleurotus cornucopiae, were investigated. The inhibitor was maximally extracted when the P. cornucopiae fruiting body was treated with distilled water at 30℃ for 12 h. Purification was achieved using Sephadex G-100 and G-50 filtration chromatography, pepsin hydrolysis, and reverse-phase HPLC. The compound’s solid yield and inhibitory activity were 12.2% and 9.10 mg/ml of IC₅₀, respectively. The purified inhibitor contained two hexapeptides with Thr-Ile-Ala-Phe-Ile-Asp (A) and Tyr-Tyr-Ala-Ile-Gly-Asp (B) sequences and molecular weights of 678.79 Da (A) and 643.7 Da (B). The purified inhibitor showed a mixed inhibition pattern to α-glucosidase and a dose-dependent anti-hyperglycemic effect in a streptozotocininduced diabetic Sprague-Dawley rat model, exhibited by decreased blood glucose levels at doses of 50 and 300 mg/kg.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.174-177
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• 2015

A potent α-glucosidase inhibitor (compound I) was isolated from coffee brews by activity-based fractionation and identified as a β-carboline alkaloid norharman (9H-pyrido[3.4-b]indole) on the basis of mass spectroscopy and nuclear magnetic resonance spectra (¹H NMR, ¹³C NMR, and COSY). The norharman showed potent inhibition against α-glucosidase enzyme in a concentration-dependent manner, with an IC₅₀ value of 0.27 mM for maltase and 0.41 mM for sucrase. A Lineweaver-Burk plot revealed that norharman inhibited α-glucosidase enzyme uncompetitively, with a K_i value of 0.13 mM.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.381-383
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• 2014

In the course of screening for ${\alpha}$-glucosidase inhibitor produced by microorganism, the active compound was isolated from the culture filtrate of Bacillus sp. SKU31-1 using a series of chromatography procedures. The structure of the active compound was elucidated as 5-amino-1-hydroxymethyl-1, 2, 3, 4-cyclohexanetetrol on the basis of spectroscopic evidence obtained and comparison with data from the literature. The active compound showed potent inhibitory activity against ${\alpha}$-glucosidase with an $IC_{50}$ value of $1.9{\mu}M$ for maltose and 4.9 mM for sucrose. A Lineweaver-Burk plot indicated that its inhibition of ${\alpha}$-glucosidase was competitive, with a $K_i$ value of 0.15 mM.

• International Journal of Industrial Entomology and Biomaterials
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• v.33 no.1
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• pp.24-30
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• 2016

1-Deoxynojirimycin (DNJ) have been extensively investigated for their α-glucosidase inhibitor on postprandial hyperglycemia, and applied in nutraceuticals and medicine for preventing or delaying progression of type 2 diabetes. However, the amount of DNJ in mulberry leaves is low (about 0.1%), therefore, more effective extraction method is needed. This study was performed to develop microbial DNJ for biological methods of DNJ as an alternative to the chemical methods. In this study, we obtained evidence for Bacillus subtilis that produce DNJ in large quantities by high performance liquid chromatography. Inhibition of α-glucosidase activity was determined to DNJ production or non-production. Investigation of the effect of mulberry leaves powder concentration (1~5%), using the DNJ high-production bacteria, provided evidence for microbial mass production of DNJ. When the 4% mulberry leaf powder for 9 days was used, the α-glucosidase inhibitory activity was over the 85%. Also, the results presented in this study confirm DNJ yield's increasement in microbes using the various of nutrients and provide insight of ways to improve DNJ yields in microorganisms.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.308-315
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• 2011

We investigated ${\alpha}$-amylase, ${\alpha}$-glucosidase and lipase inhibitory activity of extracts collected from wild plants in Gangwon-do. 90 wild plants were collected and their water and ethanol extracts were obtained. Results of measuring ${\alpha}$-amylase inhibitory activity indicated more than 80% of activity inhibition in 10 mg/mL concentration for ethanol extracts of three plants and water extracts of two plants. For ${\alpha}$-glucosidase inhibitory activity, ethanol extracts of thirteen plants and water extracts of three plants showed more than 80% of activity inhibition in 10 mg/mL concentration. In the experiment of inhibiting lipase activity, ethanol extracts of seven plants and water extracts of one plants showed above 80% of activity inhibition in 10 mg/mL concentration. These results suggest that the selected extracts could be potentially used as a resource of bioactive materials for health functional foods.

• Preventive Nutrition and Food Science
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• v.19 no.1
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• pp.5-9
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• 2014

This study was designed to investigate the inhibitory effects of Polyopes lancifolia extract (PLE) on ${\alpha}$-glucosidase activity, ${\alpha}$-amylase activitiy, and postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. The results of this study revealed a marked inhibitory effect of PLE on ${\alpha}$-glucosidase and ${\alpha}$-amylase activities. The $IC_{50}s$ of PLE against ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.20 mg/mL and 0.35 mg/mL, respectively. PLE was a more effective inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase activities than acarbose, the positive control. The postprandial blood glucose levels of STZ-induced diabetic mice were significantly lower in the PLE treated group than in the control group. Moreover, PLE administration was associated with a decreased area under the curve for the glucose response in diabetic mice. These results indicate that PLE may be a potent inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase activities and may suppress postprandial hyperglycemia.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.566-575
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• 2021

Galactose and soybean meal were selected as the best carbon and nitrogen sources, repectively, for the efficient production of α-glucosidase inhibitor (AGI) and 1-deoxynojirimycin (DNJ) by a newly isolated Bacillus subtilis MORI. The optimal concentrations of the galactose and soybean meal for the production of AGI and DNJ were investigated by response surface methodology. For the production of AGI, the optimal galactose and soybean meal concentrations were 4.3% (w/v) and 3.2% (w/v), respectively, and for DNJ, 4.5% (w/v) and 3.0% (w/v), respectively. The nearly identical optimal concentrations of galactose and soybean meal for the production of both AGI and DNJ indicated a close correlation between the production of AGI and DNJ. The maximum production of AGI (50,880 GIU/ml) and DNJ (824 ㎍/ml) obtained from the statistically optimized medium in a jar fermenter was 2.33 and 2.38-fold, respectively, higher than those (21,798 GIU/ml and 346 ㎍/ml, respectively) of the pre-optimized medium. The production of both AGI and DNJ was greatly increased by jar fermentation (AGI of 38,524 GIU/ml and DNJ of 491 ㎍/ml) compared with flask fermentation.

• The Korean Journal of Mycology
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• v.44 no.1
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• pp.57-60
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• 2016

Following preparation of water extracts of Pleurotus cornucopiae fruiting body-containing ${\alpha}$-glucosidase inhibitor, their antihyperglycemic effects were examined using streptozotocin-induced diabetic Sprague-Dawley (SD)-rats. The water extracts from Pleurotus cornucopiae showed dosage-dependant antihyperglycemic effects on the streptozotocin-induced diabetic SD-rats after oral administration to 120 min on the short time test and 4 days on the long time test, respectively. The water extracts from Pleurotus cornucopiae fruiting body showed dosage-dependent hypoglycemic action after administration to 120 min and 4 days in the SD-rat and streptozotocin-induced diabetic SD-rat.

• Korean Journal of Pharmacognosy
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• v.46 no.2
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• pp.105-108
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• 2015

To establish the anti-diabetic(α-glucosidase inhibitory) activity of D. lotus leaf extract, isolate and identify the constituents responsible for the activity. The methanolic extract of leaves was partitioned between water, n-butanol and ethyl acetate. Bio-assay guided fractionation, based on inhibition of ;${\alpha}$-glucosidase, allowed isolation and identification of the active components. Liquid chromatography/mass spectrometry(LC/MS), ¹ H-NMR and ¹³ C-NMR spectra analyses demonstrated that the active compound was myricetin-3-O-;${\alpha}$-L-rhamnoside(1). Compound 1 demonstrated a strong inhibition on the α-glucosidase, in vitro and ;${\alpha}$-glucosidase inhibitory value was calculated as 98.08%, when that of a reference drug, acarbose was estimated as 83.03%. The present study indicates compound 1 could be considered as an ;${\alpha}$-glucosidase inhibitor and developed as an important antidiabetes agent for type II diabetes therapy.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.921-927
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• 2008

Discovery of $\alpha$-glucosidase inhibitors has been actively pursued with the aim to develop therapeutics for the treatment of diabetes and the other carbohydrate mediated diseases. As a method for the discovery of new novel inhibitors of $\alpha$-glucosidase, we have addressed the performance of the computer-aided drug design protocol involving the homology modeling of $\alpha$-glucosidase and the structure-based virtual screening with the two docking tools: FlexX and the automated and improved AutoDock implementing the effects of ligand solvation in the scoring function. The homology modeling of $\alpha$-glucosidase from baker’s yeast provides a high-quality 3-D structure enabling the structure-based inhibitor design. Of the two docking programs under consideration, AutoDock is found to be more accurate than FlexX in terms of scoring putative ligands to the extent of 5-fold enhancement of hit rate in database screening when 1% of database coverage is used as a cutoff. A detailed binding mode analysis of the known inhibitors shows that they can be stabilized in the active site of $\alpha$- glucosidase through the simultaneous establishment of the multiple hydrogen bond and hydrophobic interactions. The present study demonstrates the usefulness of the automated AutoDock program with the improved scoring function as a docking tool for virtual screening of new $\alpha$-glucosidase inhibitors as well as for binding mode analysis to elucidate the activities of known inhibitors.