• Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.181-187
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• 2023

The control of intestinal α-amylase and α-glucosidase is an effective therapeutic strategy for prevention of post-prandial hyperglycemia associated with diabetes mellitus. The objective of this study was to evaluate the anti-diabetes activities of Korean edible seaweed against α-amylase and α-glucosidase, two carbolytic enzymes involved in serum glucose regulation. Of the 41 species initially screened, Cladophora wrightiana var. minor, Eisenia bicyclis, Ecklonia cava, Ishige foliacea, and Ishige okamurae exhibited the strongest inhibitory activities from brown seaweeds. Asparagopsis taxiformis showed the strongest inhibitory effects from red seaweeds. The results of this study suggest that the crude brown seaweed extracts (C. wrightiana var. minor, E. bicyclis, E. cava, I. foliacea, and I. okamurae) and crude red seaweed extracts (A. taxiformis) may have beneficial effects suppressing the rise in postprandial hyperglycemia through the inhibition of α-amylase and α-glucosidase.

• Mycobiology
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• v.41 no.3
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• pp.149-154
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• 2013

An ${\alpha}$-glucosidase inhibitor was developed from Aspergillus oryzae N159-1, which was screened from traditional fermented Korean foods. The intracellular concentration of the inhibitor reached its highest level when the fungus was cultured in tryptic soy broth medium at $27^{\circ}C$ for five days. The inhibitor was purified using a series of purification steps involving ultrafiltration, Sephadex G-25 gel permeation chromatography, strong cation exchange solid phase extraction, reverse-phase high performance liquid chromatography, and size exclusion chromatography. The final yield of the purification was 1.9%. Results of the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis indicated that the purified ${\alpha}$-glucosidase inhibitor was a tri-peptide, Pro-Phe-Pro, with the molecular weight of 360.1 Da. The IC50 value of the peptide against ${\alpha}$-glucosidase activity was 3.1 mg/mL. Using Lineweaver-Burk plot analysis, the inhibition pattern indicated that the inhibitor acts as a mixed type inhibitor.

• Korean Journal of Plant Resources
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• v.31 no.3
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• pp.237-253
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• 2018

The adzuki bean (Vigna angularis L.) is a red-grained legume that has a number of essential nutrients and is used in traditional dishes in Asia. Adzuki bean industrial by-products are also a potential low-cost source of some unique bioactive polyphenols. Hence, here, the authors aimed to perform a comparative study of the phytochemical profiles of the leaves and seeds of the adzuki bean and compare their antioxidant, ${\alpha}$-glucosidase inhibition, and tyrosinase inhibition activity. The authors assessed antioxidant activity by DPPH, ABTS, FRAP, PR, TPC, and SOD assays, which showed wide variation, respectively. From the relative antioxidant capacity index results, 10 adzuki bean landraces were selected to compare for phytochemicals and bioactivity using leaf and seed extracts. Antioxidant, ${\alpha}$-glucosidase inhibition, and tyrosinase inhibition activity in the leaf extracts were higher than in the seed extracts, and there were more flavonols and isoflavones in the leaf extracts than in the seed extracts. This study demonstrated that adzuki bean leaf extracts could be a new natural antioxidant or antidiabetic agent and a skin whitener and can also be used in industrial applications.

• Food Science and Preservation
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• v.16 no.5
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• pp.734-741
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• 2009

Response surface methodology (RSM) was used to optimize extraction conditions for functional components of buckwheat (Fagopyrum esculentum). A central composite design was applied to investigate the effects of three independent variables, namelyextraction temperature (X1), extraction time (X2), and ethanol concentration (X3), on responses including extraction yield (Y1), total phenolic content in the extract (Y2), $\alpha$-glucosidase inhibition activity (Y3), and acetylcholine esterase (ACE) inhibition activity (Y4). Data were analyzed using an expert design strategy and statistical software. The maximum yield was 24.95% (w/w) at $55.75^{\circ}C$ extraction temperature, 8.75 hextraction time, and 15.65% (v/v) ethanol. The maximum total phenolic yield was 222.45 mg/100 g under the conditions of $28.11^{\circ}C$ extraction temperature, 8.65 h extraction time, and 81.72% (v/v) ethanol. The maximum $\alpha$-glucosidase inhibition activity was 85.38% at $9.62^{\circ}C$, 7.86 h, and 57.58% (v/v) ethanol. The maximum ACE inhibition activity was 86.91% under extraction conditions of $10.12^{\circ}C$, 4.86 h, and 44.44% (v/v) ethanol. Based on superimposition of a four-dimensional RSM with respect to levels of total phenolics, $\alpha$-glucosidase inhibition activity, and ACE inhibition activity, obtained under various extraction conditions, the optimum ranges of conditions were an extraction temperature of $0-70^{\circ}C$, an extraction time of 2-8 h, and an ethanol concentration of 30-80% (v/v).

• Korean Journal of Pharmacognosy
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• v.40 no.2
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• pp.150-154
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• 2009

We examined ethanol extracts prepared from the Korean marine algae belonging to the Sargassaceae family for their inhibitory effects on ${\alpha}$-glucosidase activity and free radicals in vitro. Among five marine algae, the extracts of Sargassum yezoense were found to possess strongly ${\alpha}$-glucosidase inhibition and free radicals scavenging activities. Two compounds were isolated via bioactivity guided isolation and tested for their effects on ${\alpha}$-glucosidase, DPPH, $ABTS^{+}$ and $Photochem^{(R)}$ analysis. Their chemical structures were elucidated by spectral analysis and direct comparison with authentic compounds; their structures were identified as sargaquinoic acid (1) and sargahydroquinoic acid (2). The inhibitory effects of compound 1 and 2 ($IC_{50}$ value:14.2 and 12.8 ${\mu}M$, respectively) on ${\alpha}$-glucosidase were more potent that of deoxynojirimycin as a positive control ($IC_{50}$ value:18.0 ${\mu}M$). All compounds displayed antioxidative activity which was measured by DPPH, $ABTS^{+}$ and $Photochem^{(R)}$ apparatus.

• YAKHAK HOEJI
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• v.55 no.6
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• pp.446-450
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• 2011

As an effort to find a new scaffold for ${\alpha}$-glucosidase inhibition, we have prepared total 11 phenylalkylated piperazine derivatives and tested their ${\alpha}$-glucosidase inhibitory activities. Compounds 8 ($IC_{50}=2.73{\pm}0.075mM$) possessing two 3-methoxyphenethyl group on 1,4-position of piperazine showed comparable potency to acarbose used as reference. But other compounds were inactive to ${\alpha}$-glucosidase. The result indicated that proper substituents on the piperazine can engender ${\alpha}$-glucosidase inhibitory activities on the piperazine derivatives.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.681-686
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• 2015

The purpose of this study was to measure total phenolic compounds as a measure of antioxidant activity as well as ${\alpha}$-amylase inhibitory and ${\alpha}$-glucosidase inhibitory activities as a measure of anti-diabetic efficacy in methanol extracts from 23 kinds of medicinal plants. Extracts of three medicinal plant species showing high total polyphenol contents were selected (Euonymus alatus stem, Taxus cuspidata fruit, and Eucommia ulmoides leaf). Extracts of six medicinal plant species showing over 60% DPPH radical scavenging activity were also selected [Eucommia ulmoides barks (80.10%), Lycium chinense roots (64.25%), Euonymus alatus stem (73.59%), Lespedeza cuneata (78.20%), Taxus cuspidata fruits (70.52%), and Tilia taquetii leaf and stem (67.81%)]. Regarding ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory activities acarbose showing approximately 80% inhibitory activity was selected as a control group, and six species (Eucommia ulmoides heartwood, Eucommia ulmoides bark, Euonymus alatus stem, Dioscorea batatas, Coix lachryma-jobi, and Phaseolus radiatus) showed greater than 80% ${\alpha}$-glucosidase inhibitory activity. Extracts of nine medicinal plant. species showing over 80% ${\alpha}$-amylase inhibitory activity (Pueraria thunbergiana root, Eucommia ulmoides bark, Eucommia ulmoides leaf, Lycium chinense fruits, Euonymus alatus leaf and stem, Euonymus alatus stem, Sasa borealis whole, Dioscorea batatas leaf and stem, and Tilia taquetii leaf and stem). Based on these results, medicinal plants showing high antioxidant and antidiabetic activities can be used as fundamental products in developing new medicines, as well as functional foods to prevent adult disease.

• Archives of Pharmacal Research
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• v.20 no.4
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• pp.346-350
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• 1997

The synthesis of cis- and trans-1,6-dihydroxypyrrolizidine starting from trans-4-hydroxy-L-proline and their evaluation as glycosidase inhibitors are reported. The cis-isomer was found to be a potent inhibitor against .alpha.-glucosidase and showed weak inhibitory effect against other glycosidases. The trans-isomer exhibited weak inhibitions of b-glucosidase and amylo-glucosidase and poor inhibition of other glycosidases.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.498-503
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• 2015

This study was conducted to evaluate the cytotoxicity and ${\alpha}-Amylase$, ${\alpha}-Glucosidase$, pancreatic lipase inhibition in vitro by different solvent fractions from the roots of Codonopsis lanceolata. The values of $IC_{50}$ against Calu-6 cell showed a high effect in n-hexane fraction ($10.13{\mu}g/mL$) whereas DW fraction exhibited the weakest inhibition on cell viability, having an $IC_{50}$ value of over $1,000{\mu}g/mL$. The values of $IC_{50}$ against HCT-116 cell showed the highest activity in n-BuOH fraction ($102.01{\mu}g/mL$), followed by n-hexane fraction ($145.85{\mu}g/mL$), methylene chloride fraction ($332.02{\mu}g/mL$), ethyl acetate fraction ($462.93{\mu}g/mL$) and DW fracion ($>1,000{\mu}g/mL$). ${\alpha}-Amylase$ inhibitory activity in methylene chloride fraction and ethyl acetate fraction was found to have a higher inhibitory effect with 24.5% and 25.6% than the other fractions. The highest ${\alpha}-Glucosidase$ inhibitory activity was observed from the ethyl acetate fraction extract, while the extract of DW fraction showed the lowest level of inhibitory activity at given experiment concentration. The pancreatic lipase inhibitory activity of C. lanceolata was found to have a higher the effect in ethyl acetate fraction. Inhibition of lipase activity of the ethyl acetate fraction and n-hexane fraction showed a relatively high, while the extract of DW fraction showed the lowest level at given experiment concentration. These results suggested that the roots of C. lanceolata may assist in the potential biological activity on carbohydrate, lipid Inhibitory activity and anticancer activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.7
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• pp.1079-1085
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• 2013

This study investigated how different amounts of omija fruit (Schisandra chinensis) juice concentrate (0~5%) in sauces affect perceived sensory and quality characteristics. Sauce samples were subjected to chemical analysis for different quality parameters such as Brix, reducing sugars, total phenolic compounds, alpha-amylase inhibition, and alpha-glucosidase inhibition activity. A decrease in pH values was observed with increasing concentrate percentage. As for color, the more concentrate added, the more the L value decreased and other values ($a^*$, $b^*$ and ${\Delta}E$ values) increased. Hypoglycemic effect, as determined by alpha-glucosidase, valuably increased in 4% juice concentrate. As the percentage of concentrate increased, the chemical component values also increased. Significant differences were observed between sauce samples in the sensory evaluation, with the highest overall acceptance being sauce containing 4% juice concentrate. When evaluated with marinated chicken breasts, sauce containing 5% juice concentrate achieved the maximum score.