• Food Science and Preservation
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• v.23 no.7
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• pp.989-994
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• 2016

As part of our continuing search for bioactive natural products, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of an 80% methanolic extract and organic solvent soluble-portions of Aruncus dioicus var. kamtschaticus roots were investigated by using a bioassay system. The antioxidant activity of A. dioicus var. kamtschaticus roots extract and organic solvent soluble-portions were assessed by examining with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radical scavenging. In addition, anti-diabetic effects of the A. dioicus var. kamtschaticus root extract and organic solvent soluble-portions were tested via ${\alpha}$-glucosidase inhibition assay. The total phenolic contents of the products were determined by applying UV-VIS spectrophotometry. All tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory properties. In particular, the ${\alpha}$-glucosidase inhibitory and radical scavenging effects of the ethyl-acetate (EtOAc)-soluble portion from the roots of A. dioicus var. kamtschaticus were greater than those from other solvent-soluble portions. These results indicate that A. dioicus var. kamtschaticus could be considered a new effective source of natural antioxidants and anti-diabetic materials. More systematic research of the constituents of the roots of this A. dioicus variety will be conducted to further develop its antioxidative and anti-diabetic properties.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.103-108
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• 2005

${\alpha}-Amylase$ inhibitor is used to control blood glucose level by inhibiting starch digestion in the small intestine and delaying the absorption of glucose. In this study, we investigated the effect of the ethanol extracts from more than 1400 species of plants against ${\alpha}-amylase$ with the aim of developing a new ${\alpha}-amylase$ inhibitor. In the results, Cornus walteri extracts showed the highest inhibition activity. The inhibitory effect of Cornus walteri extract on the carbohydrate hydrolysis enzymes has different sensitivities against ${\alpha}-amylase$ from salivary and pancreatin and against ${\alpha}-glucosidase$ from yeast and porcine small intestine. In the study of inhibition kinetics of ${\alpha}-amylase$ and ${\alpha}-glucosidase$, Cornus walteri extract showed competitive inhibition against salivary and pancreatin while showing the combination of uncompetitive and noncompetitive inhibition against ${\alpha}-glucosidase$. The Cornus walteri extract was stable at acidic and thermal conditions. As for the blood glucose and body weight levels of Cornus walteri extract, we confirmed anti-hyperglycemic and anti-obesity effects. Also, in the investigation of the mRNA lever, Cornus walteri extract upregulated the level of GLUT4 mRNA in the quadriceps muscle.

• Journal of Life Science
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• v.21 no.11
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• pp.1579-1585
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• 2011

Natural anti-diabetic semipurified ethyl acetate fraction was isolated from the submerged-liquid culture of Agaricus blaze Murill (AB) in a medium containing soybean flakes. Hot-water extract of AB (HEAB) was prepared by extraction at $121^{\circ}C$ for 60 min, followed by filtering through a filter presser filled with diatomate. The ${\beta}$-glucan-free HEAB, which was a supernatant fraction from HEAB by precipitation in an 80% ethanol solution, was fractionated into hexane, chloroform, ethyl acetate, and butanol fractions. The inhibition of the ${\alpha}$-glucosidase activity by fractions was 59.0, 17.0, 61.6, and 37.9%, respectively, suggesting that ethyl acetate fraction was the most active. A subfraction having a strong ${\alpha}$-glucosidase inhibitory activity (80.4%) was isolated from the ethyl acetate fraction. This subfraction contained isoflavones (genistin and daidzin) and their conjugates with sugars as potent inhibiters of ${\alpha}$-glucosidase activity. These results suggest that the ethyl acetate fraction or HEAB containing isoflavones and their sugars conjugates could be useful sources for controlling blood sugar levels in humans.

• Food Science and Preservation
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• v.17 no.2
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• pp.290-296
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• 2010

To develop anti-acidosis and anti-diabetes agentsfrom natural products, the inhibitory activities of Brazilian plant extracts against microbial $\alpha$-amylase and $\alpha$-glucosidase were evaluated. Among 100 different ethanol extracts tested, those of Acacia jurema Mart., Anacardium humile A. St.-Hil., Cedrela odorata L., and Guazuma ulmifolia Lam showed good inhibitoryactivities toward both enzymes. In addition, an extract of Plumeria drastica Mart. showed specific inhibition of $\alpha$-amylase, whereas that of Eugenia uniflora L. demonstrated strong inhibition of the enzyme. IC50 values of $\alpha$-amylase inhibition suggested that the extract of A. humile A. St.-Hil., which has been used as an anti-diabetes medicine in Brazil, had potent inhibitory activity. The IC50 for the A. humile A. St.-Hil. extract ($91.2{\mu}g/mL$) was similar to that of acarbose ($50.5{\mu}g/mL$). This activity of A. humile A. St.-Hil. was not reduced by heat or acid treatment. Moreover, treatment with HCl (0.01 M) for 1 h increased the inhibitory activity from 57.5% to 81.2%. Also, the extract did not cause hemolysis of human red blood cells at levels up to 1 mg/mL. The results indicate that the extract of A. humile A. St.-Hil. is potentially useful as an anti-acidosis and anti-diabetes agent.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.219-224
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• 2014

In order to develop a new anti-diabetic ${\alpha}$-glucosidase inhibitor, we compared the ${\alpha}$-glucosidase inhibitory activity of the cell-free extracts of 48 strains of yeasts isolated from Korean fermented foods, and found that Pichia burtonii Y257-7 exhibited the highest ${\alpha}$-glucosidase inhibitory activity of 55.6%. The ${\alpha}$-glucosidase inhibitor was maximally produced when Pichia burtonii Y257-7 was cultured in LB broth (initial pH of 6.0) at $28^{\circ}C$ for 24 h. The ${\alpha}$-glucosidase inhibitor, partially purified by Sephadex G-50 gel permeation chromatography and systematic solvents extraction, revealed potent hypoglycemic effects in normal rats and streptozotocin-induced diabetic rats after the oral administration of starch.

• Food Science and Preservation
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• v.23 no.1
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• pp.80-88
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• 2016

Seven kinds (acacia, cochineal, catechu, grape peel, persimmon, gallnut and clove) of color powders obtained from natural resources and their mixtures were evaluated for their biological activities, such as antioxidant (ABTS and DPPH radicals scavenging), cholesterol absorption, and COX-2 inhibitory activities. Catechu, gallnut and clove were selected for the further studies due to its the best activities. The cholesterol absorption, COX-2 inhibitory, ${\alpha}$-amylase inhibitory and ${\alpha}$-glucosidase inhibitory activities were measured using the mixtures of catechu, gallnut and clove. The ABTS radical scavenging activity of the seven types of natural color powders were higher than the DPPH radical scavenging activity. The cholesterol absorption activity was significantly higher in cloves. The COX-2 inhibitory activity was significantly lower in acacia. The ${\alpha}$-amylase inhibitory activity was higher in catechu and gallnut, indicating that there were no significant difference between two mixtures. The ${\alpha}$-glucosidase inhibitory activity was the highest in catechu, which was higher than that of the catechu-containing mixtures. From all these results, a synergistic effect could be obtained when utilizing a mixture of powders rather than using only individual type. Since the activity of each powder was different, further studies will be required for clarifying the interactions between mixtures.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.8
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• pp.989-994
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• 2007

This study was designed to investigate whether Sasa borealis leaves extracts (SLE) may inhibit yeast ${\alpha}-glucosidase$ and ${\alpha}-amylase$ activities and postprandial hyperglycemia in STZ-induced diabetic mice. Freeze-dried SLE was extracted with 70% methanol and followed by a sequential fractionation with dicholoromethan, ethylacetate, butanol, and water. Both ethylacetate and butanol fractions showed high inhibitory activities against the ${\alpha}-glucosidase$ and ${\alpha}-amylase$ enzymes. The $IC_{50}$ of ethylacetate and butanol fractions against ${\alpha}-glucosidase$ were 0.54 and 0.63 mg/mL, respectively, indicating a greater inhibition effect than acarbose (0.68 mg/mL) (p<0.05). Likewise, the two fractions exhibited a smaller $IC_{50}$ against ${\alpha}-amylase$, compared with acarbose (p<0.05). However, the yield of ethylacetate fraction of SLE was relatively small. Postprandial blood glucose testing of normal mice and STZ-induced diabetic mice by starch soln. loading (2 g/kg B.W.) showed that postprandial blood glucose level at 30, 60, and 120 min were markedly decreased by single oral administration of SLE butanol fraction (200 mg/kg B.W.) in both normal (p<0.0l) and diabetic mice (p<0.0l). Furthermore, the incremental area under the curve (AUC) was significantly lowered via SLE administration (5,745 versus 12,435 $mg{\cdot}mim/dL$) in the diabetic mice (p<0.0l). The incremental AUC in normal mice corroborated the hypoglycemic effect of SLE (p<0.0l) found in the diabetic mice. These results suggest that SLE may delay carbohydrate digestion and thus glucose absorption. In addition, SLE may have the potential to prevent and treat diabetes via its ability on lowering postprandial hyperglycemia.

• Food Science and Preservation
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• v.21 no.2
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• pp.254-263
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• 2014

This study was carried out to analyze the effects of water and 70% ethanol extract on the antioxidative and antidiabetic activities of Smilax china L., a vine shrub belonging to the lily family. The activities of the extracts were measured based on the total phenolic and flavonoid contents and through on the results of the antioxidant tests, such as the electron-donating ability, ABTs radical scavenging activities, SOD-like activity, xanthine oxidase inhibition effect, antioxidant protection factor (PF), TBARs content and ACE inhibition activity, and ${\alpha}$-glucosidase, and ${\alpha}$-amylase inhibition activity. The resulting total phenolic and flavonoid contents of the 70% ethanol extract from S. china L. were greater than those of the water extract from S. china L. With regard to the results of the antioxidant tests, such as the electron-donating ability, ABTs radical scavenging activity, SOD-like activity, xanthine oxidase inhibition effect, antioxidant protection factor (PF), and TBARs content, those from the 70% ethanol extract from S. china L. were greater than those from the water extract from S. china L. Also, with regard to the ACE inhibition effect and ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibition, those from the 70% ethanol extract from S. china L. were greater than those from the water extract from S. china L. All these findings show that the 70% ethanol extract from S. china L. has greater antioxidative and antidiabetic effects and can be used as a preventive agent for oxidation and diabetes.

• Journal of Life Science
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• v.21 no.7
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• pp.1016-1024
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• 2011

The concentrations of bioactive material (polyphenolics and flavonoids) and the biological activities of antioxidative (DPPH [${\alpha},{\alpha}'$-diphenyl-${\beta}$-picrylhydrazyl] free radical scavenging activity, peroxidation of rat liver microsome, and Fe/Cu reducing power), ${\alpha}$-glucosidase inhibition, tyrosinase inhibition, and fibrinolytic activity were tested by in vitro experimental models using 70% methanolic extract from Ganoderma lucidum, Momordica charantia, Fagopyrum tataricum and their mixtures. The highest yield and the concentrations of polyphenolics and flavonoids were shown in the mixture extract. Mixture extract was shown to have the highest activities of ${\alpha}$-glucosidase inhibition and tyrosinase inhibition, fibrinolytic, DPPH free radical scavenging, and Fe/Cu reducing power in a concentration-dependent manner. From these results, mixture methanol extract was shown to have the most potent bioactive properties and to contain large amounts of biological materials such as polyphenolics and flavonoids. This mixture could be a good dietary supplement material candidate, such as for antidiabetic functional foods.