• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.558-561
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• 2008

Culture broth of Bacillus subtilis Y3-7 in tryptic soy broth (TSB) isolated from Korean traditional fermented food was evaluated for the inhibition of $\alpha$-glucosidase. The results of in vitro studies using the yeast $\alpha$-glucosidase demonstrated that the culture broth exerted inhibitory effects on $\alpha$-glucosidase with $IC_{50}$ value of 1.62 mg/mL, and functioned as a competitive inhibitor. Furthermore, the culture broth of B. subtilis Y3-7 significantly improved glucose tolerance in normal and streptozotocin-induced diabetic mice. The blood glucose levels in the mice receiving sucrose supplementation in the culture broth (1 g/kg, 2 g/kg) were measured at 48.7%, which corresponded to 22.2% of the levels measured in the control mice. These results indicated that the culture broth of B. subtilis Y3-7 in TSB might be considered as a useful compound for the preparation of functional foods for diabetic patients.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.164-169
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• 2015

This study evaluated in vitro antioxidant activity, antioxidant content, and ${\alpha}$-glucosidase and pancreatic lipase inhibitory activities of ethanol extracts of samnamul (shoot of Aruncus dioicus), miyeokchwi (Solidago virgaurea), daraesoon (shoot of Actinidia arguta Planchon), and bangpungnamul (leaves of Ledebouriella seseloides), as muknamul, and fresh chamnamul (Pimpinella brachycarpa). Tocopherol content (4.8-78.3 mg/100 g) of sanchae was lower than polyphenols (4.4-12.2 g/100 g). Daraesoon with high tocopherol contents showed high antioxidant activity and ${\alpha}$-glucosidase and pancreatic lipase inhibitory activities. Samnamul had the highest levels of polyphenols and flavonoids, the highest antioxidant activity, and ${\alpha}$-glucosidase inhibition. Antioxidant activity was correlated with flavonoid content ($r^2=0.8895$), but was not correlated with the levels of other antioxidants tested, suggesting that polyphenol content in samnamul, miyeokchwi, daraesoon, bangpung, and chamnamul might not be critical determinant of antioxidant activity. Our results strongly suggest that samnamul and daraesoon could be useful in the treatment of diabetes and obesity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.437-444
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• 2010

Extracts of the marine microalgae Nannochloropsis oculata were obtained using 80% methanol (MeOH) and water. The 80% MeOH extract was further fractionated with n-hexane, chloroform, ethyl acetate (EtOAc), n-butanol (n-BuOH), and water to isolate the active fraction. Seven samples were prepared and their angiotensin converting enzyme (ACE), $\alpha$-glucosidase, and cancer cell growth inhibitory activities in vitro were determined. The most profound ACE inhibitory activity was observed in the chloroform fraction, while the others had moderate effects. By contrast, greater $\alpha$-glucosidase inhibitory activity was found in the EtOAc fraction, n-hexane fraction, and water extract of N. oculata. The antiproliferative effects of the extracts and fractions against HL-60, U937, CT-26, and SK-Hep1 cancer cells were also determined. The n-BuOH fraction had the strongest antiproliferative effects on CT-26 cells in a time-dependant manner (P<0.05). These results suggest that the extracts and fractions from N. oculata could be used as a potential functional food or as pharmaceutical ingredients.

• Korean Journal of Medicinal Crop Science
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• v.19 no.4
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• pp.257-263
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• 2011

This study investigated the changes of antioxidant activity and ${\alpha}$-glucosidase inhibitory effect of Jerusalem artichoke (Helianthus tuberosus) 100% methanol extracts by various heat treatment. The contents of total phenolic and flavonoid compounds in methanol extract tended to increased gradually with the rise of temperature to 180$^{\circ}C$. The maximum yield of gallic acid (51.52 ${\pm}$ 2.17mg/g extract weight) and quercetin (13.39 ${\pm}$ 0.03mg/g extract weight) were obtained with extraction temperature of 180$^{\circ}C$ for 120min. In addition, the improving extraction efficiency resulted in the increased biological activities, such as electronic donation ability (EDA, 90.36${\pm}$ 0.57%), reducing power (Abs 1.14) and ${\alpha}$-glucosidase inhibitory effect (92.14 ${\pm}$ 1.14%). Overall, the results of this study indicate that the optimum conditions for the extraction process were an extraction temperature at 180$^{\circ}C$ for 120 min, and will provide the basis for future research on the improving extraction yield of phenolic and flavonoid compounds.

• 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.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.529-532
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• 1989

A strain of Streptomyces sp. (YS-221-B) extracellularly produced an inhibitory substance for $\alpha$-D-Glucosidase. The substance was purified 96-fold from culture filtrate by dialysis, heat treatment, adsorption on active carbon, Bio-Gel P-10 and Sephadex G-75 column chromatography with yield of 9.2%. The substance was stable in pH range from 7.0 to 11.0 at 37$^{\circ}C$, and a treatment at 10$0^{\circ}C$ for 20 min diminished only 15% of the original activity. The inhibitor was not inactivated by the treatment of $\alpha$-, $\beta$-amylases, glucoamylases, trypsin and chymotrypsin but inactivated by pyoteases from Streptomyces griseus and Tritirachium album.

• Biomedical Science Letters
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• v.18 no.1
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• pp.35-41
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• 2012

Physiological activities of hot water extract and solvent fractions isolated from Astragalus membranaceus were examined and the antioxidative, fibrinolytic, thrombin inhibitory and a-glucosidase inhibitory activity were measured. The hot water extract of Astragalus membranaceus was fractionated into hexane, chloroform, ethyl acetate, butanol and water fractions, and each of these fractions was individually assayed. The antioxidative activities of ethyl acetate and chloroform fractions were 89.96% and 87.36%, respectively. Using the fibrin plate method, only the hot water extract showed a plasmin activity of 0.41 units/ml. The thrombin inhibitory activity of the ethyl acetate fraction was the highest with a value of 82.73%. The hot water extract displayed a-glucosidase inhibitory activity of 64.91%. In conclusion, the hot water extract and the ethyl acetate fraction can be used as materials for the development of biofunctional foods to prevent cardiovascular diseases.

• BMB Reports
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• v.44 no.6
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• pp.410-414
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• 2011

Chana series are new chalcone derivatives. To evaluate the possibility of Chana series as therapeutic agents of type 2 diabetes, the inhibitory effects of Chana series on the activities of ${\alpha}$-glucosidase and DPP-4 were investigated using in vitro enzyme assays, and their effects on adipocyte differentiation were investigated in C3H10T1/2 cells. Chana 1 and Chana 7 among the Chana series showed significant inhibition of ${\alpha}$-glucosidase activity. In DPP-4 enzyme assay, Chana 1 exhibited the highest inhibitory activity while Chana 7 did not. In MTT assay, Chana 1 did not show significant cytotoxicity up to a concentration of $250{\mu}M$, whereas cytotoxicity was observed with Chana 7 at a concentration of $300{\mu}M$. In addition, Chana 1 induced adipocyte differentiation. Therefore, Chana 1 showed inhibitory effects on ${\alpha}$-glucosidase and DPP-4 as well as a stimulatory effect on adipocyte differentiation, suggesting that Chana 1 may be a potential beneficial agent for the treatment of type 2 diabetes.

• Natural Product Sciences
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• v.18 no.1
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• pp.47-51
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• 2012

Among 38 Vietnamese medicinal plant extracts investigated for their ${\alpha}$-glucosidase inhibitory activity, 35 extracts showed $IC_{50}$ values below $250{\mu}g/mL$. The MeOH extracts of the heartwood of Oroxylum indicum, the seeds of Caesalpinia sappan, and the fruits of Xanthium strumarium exhibited strong ${\alpha}$-glucosidase inhibitory activity with $IC_{50}$ values less than $50{\mu}g/mL$. Fractionation of the MeOH extract of the heartwood of O. indicum led to the isolation of oroxylin A (1), oroxyloside (2), hispidulin (3), apigenin (4), ficusal (5), balanophonin (6), 2- (1-hydroxymethylethyl)-4H,9H-naphtho[2,3-b]furan-4,9-dione (7), salicylic acid (8), p-hydroxybenzoic acid (9), protocatechuic acid (10), isovanillin (11), and ${\beta}$-hydroxypropiovanillon (12). Compounds 1 - 3, 5, 6, 8, 10, and 12 showed more potent activities, with $IC_{50}$ values ranging from 2.13 to $133.51{\mu}M$, than a positive control acabose ($IC_{50}$, $241.85{\mu}M$). The kinetic study indicated that oroxyloside (2) displayed mixed-type inhibition with inhibition constant (Ki) was $3.56{\mu}M$.

• Natural Product Sciences
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• v.18 no.2
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• pp.130-136
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• 2012

In the present work, we have collected 19 species of macroalgae (9 Phaeophta and 10 Rhodophyta) f rom all around of Korea: Dictyopteris divaricata, D. prolifera, Myelophycus cavus, Papenfussiella kuromo, Petalonia zosterifolia, Petrospongium rugosum, Rugulopteryx okamurae, Sargassum fulvellum, S. muticum, Callophyllis japonica, Gloiopeltis tenax, Gracilaria longissima, Gracilaria vermiculophylla, Grateloupia asiatica, Grateloupia lanceolata, Grateloupia sparsa, Grateloupia turuturu, Grateloupia sp, and Polyopes affinis. The macroalgal species were extracted by 70% ethanol (EtOH) for 24 h and evaluated its inhibitory effects on ${\alpha}$-glucosidase. Among ethanol extracts, Myelophycus cavus showed the most effectively inhibitory activity ($IC_{50}$, 2.17 ${\mu}g/ml$) against ${\alpha}$-glucosidase, followed by Sargassum fulvellum (<$IC_{50}$, 8.13 ${\mu}g/ml$), Dictyopteris prolifera ($IC_{50}$, 16.66 ${\mu}g/ml$), Rugulopteryx okamurae ($IC_{50}$, 50.63 ${\mu}g/ml$), and Petrospongium rugosum ($IC_{50}$, 101.62 ${\mu}g/ml$). Furthermore, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay showed no cytotoxicity on mouse pre-adipocytes cell line (3T3-L1). These results suggest that some edible macroalgae merit further evaluation for clinical usefulness as anti-diabetic functional foods.