• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.1
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• pp.39-45
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• 2017

This study investigated the glycyrrhizic acid content and anti-diabetic activities of Glycyrrhiza uralensis (GU) depending on the cultivation region (Jecheon, Youngju, Gokseong, China, and Uzbekistan). Glycyrrhizic acid accuracy recovery and intra- and inter-day precisions (RSD%) of the method were calculated at 99.10~107.07% and 3.92 and 6.31% for GU samples, respectively, whereas the limits of detection and quantitation were 0.14 and $0.20{\mu}g/mL$. Anti-diabetic activity was measured by ${\alpha}-glucosidase$ and glucose uptake. GU (20 g) was extracted with 70% ethanol at $70^{\circ}C$ for 6 h. The Jecheon and Gokseong GU showed good inhibitory activity compared to the control. The Jecheon, Youngju, and Uzbekistan GU ethanol extracts ($100{\mu}g/mL$) showed glucose uptakes (in $C_2C_{12}$ myotube) of 124.19, 127.18, and 126.92%, respectively, compared to the positive control. In conclusion, these methods were validated for detection of glycyrrhizic acid in GU, and the results indicate that GU might have potential anti-diabetic activities.

• Korean journal of food and cookery science
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• v.31 no.2
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• pp.207-213
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• 2015

Free amino acid and mineral analysis of beverages with Gugija (Lycii fructus) extracts performed to determine the antioxidative and anti-diabetes activities of the beverages. The four major free amino acids in the water- or ethanol-extracts of the Gugija beverages were asparagine (115.23, 51.95 mg%), methionine (20.02, 22.07 mg%), aspartic acid (19.65, 13.72 mg%) and taurine (18.64, 22.44 mg%). The mineral contents of the Gugija beverages with water- and ethanol-extracts were in the order K>Mg>Na>Ca>Zn>Fe. Antioxidant activity determined by DPPH and ABTS radical scavenging activity. There was no significant difference in DPPH and ABTS radical scavenging activities between the water-extract beverages and the ethanol-extract beverages, although more phenolics and flavonoids were found in the ethanol-extract beverage. Higher anti-${\alpha}$-glucosidase activity was observed in the ethanol-extract beverage compared to acabose, which was used as the control and is an inhibitor of ${\alpha}$-glucosidase, suggesting that the Gugija beverage with ethanol extract could be a potential hypoglycemic agent.

• Journal of Nutrition and Health
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• v.43 no.3
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• pp.215-223
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• 2010

Sasa borealis leaf has been known to have anti-diabetic properties. In this study, we tried to evaluate the effects of Sasa borealis leaf extract (SBE) on the inhibition of $\alpha$-glucosidase activity and postprandial glycemic response following ingestion of four carbohydrate-rich foods; cooked rice, ramen (instant noodle), noodle, and bread. Fourteen healthy female adults consumed 50 g of glucose (control) or one of the four foods containing 50 g of available carbohydrate with or without 2,000 mg of SBE. The activity of $\alpha$-glucosidase was inhibited dose-dependently by SBE. With SBE, blood glucose concentration at 15 min and the positive area under the curve (AUC) of postprandial glycemic response at 15 min and 30 min after consuming each of the four foods were reduced significantly. As the result, total positive AUC during 120 min was decreased in case of taking cooked rice or bread. Glycemic index and glycemic load of the four foods were declined from 13% to 23% with SBE. The results of this study suggest that SBE may be effective for postprandial glucose control by inhibiting $\alpha$-glucosidase activity.

• Preventive Nutrition and Food Science
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• v.16 no.1
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• pp.89-94
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• 2011

The potential biological activities of water and ethanol extracts from two varieties of Rubus coreanus Miquel fruits produced in the Gochang-gun (GR) and Hoengseong-gun (HR) regions of Korea were examined. The hydroxyl radical ($\cdot$OH) scavenging activity, reducing power, lipid peroxidation inhibitory activity, and antiproliferative activity on cancer cells by these extracts were examined, and $\alpha$-amylase and $\alpha$-glucosidase inhibition assays were also performed. The EtOH extract from GR showed high hydroxyl radical scavenging activity ($EC_{50}=119.47{\pm}5.13\;{\mu}g/mL$), lipid peroxidation inhibitory activity ($EC_{50}=213.45{\pm}3.14\;{\mu}g/mL$) and a concentration dependence, with OD values ranging from 0.15 to 0.56 (50 to 200 ${\mu}g/mL$), for reducing power. The EtOH extract from GR has the highest antiproliferative activities on MDA-MB-231 and HepG2 cancer cells among four extracts. Meanwhile, all extracts showed certain $\alpha$-amylase and $\alpha$-glucosidase inhibition activities. These results indicate that extracts from two varieties of R. coreanus fruits have significant antioxidant, anti-diabetic and anti-tumorigenic activities, which suggest these extracts could be a potential source for pharmaceutical.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.405-409
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• 2008

This study was performed to investigate the physiological activities of Viola mandshurica. Antioxidant activity was evaluated by measuring total phenolic contents, reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-di-2-ethyl-benzthiazoline sulphonate (ABTS) radical scavenging activity while anti-diabetic activity was measured by inhibition activities on ${\alpha}$-amylase and ${\alpha}$-glucosidase. V. mandshurica extracts were prepared by extracting with four different solvents (methanol, ethanol, acetone, and water). The methanol extract showed the highest total phenol content (34.49 mg/g gallic acid equivalents) among the extracts. The water extract showed the highest reducing power (0.454) at the concentration of $1,000{\mu}g$/mL. The acetone extract showed the most potent radical scavenging activity. DPPH and ABTS radical scavenging activity of the acetone extract at the concentration of $1,000{\mu}g$/mL were 21.13% and 43.53%, respectively. The inhibitory activity of acetone extracts against ${\alpha}$-amylase and ${\alpha}$-glucosidase showed more than 100% at the concentration of $1,000{\mu}g$/mL. The results indicate that V. mandshurica might have potential antioxidant and anti-diabetic activities.

• Preventive Nutrition and Food Science
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• v.5 no.3
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• pp.174-176
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• 2000

Seventeen wild vegetables consumed commonly in Korea were tested for inhibitory activities against alpha-glucosidase, followed by Bupleurum longeradiatum and Angelica decursiva. The hexane-soluble fractions of Hosta longipes, Ainsliaea acerifolia, Pedicularis resupinata, Bupleurum longeradiatum, and Angelica decursiva all at the concentration of 5 mg/ml, inhibited enzyme activity by greater than 50%, and the ethylacetate-soluble fractions of Hosta longipes, and Codonopsis lanceolata, and Bupleurum longeradiatum had relatively strong inhibitory activity against the enzyme. These results suggest that some edible plants merit further evaluation for clinical usefulness as anti-diabetic drugs.

• Journal of Pharmacopuncture
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• v.20 no.1
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• pp.45-51
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• 2017

Objectives: This study aimed to evaluate the hypoglycemic effects of an ethanol extract of Cassia abbreviata (ECA) bark and the possible mechanisms of its action in diabetic albino rats. Methods: ECA was prepared by soaking the powdered plant material in 70% ethanol. It was filtered and made solvent-free by evaporation on a rotary evaporator. Type 2 diabetes was induced in albino rats by injecting 35 mg/kg body weight (bw) of streptozotocin after having fed the rats a high-fat diet for 2 weeks. Diabetic rats were divided into ECA-150, ECA-300 and Metformin (MET)-180 groups, where the numbers are the doses in mg.kg.bw administered to the groups. Normal (NC) and diabetic (DC) controls were given distilled water. The animals had their fasting blood glucose levels and body weights determined every 7 days for 21 days. Oral glucose tolerance tests (OGTTs) were carried out in all animals at the beginning and the end of the experiment. Liver and kidney samples were harvested for glucose 6 phosphatase (G6Pase) and hexokinase activity analyses. Small intestines and diaphragms from normal rats were used for ${\alpha}-glucosidase$ and glucose uptake studies against the extract. Results: Two doses, 150 and 300 mg/kg bw, significantly reduced the fasting blood glucose levels in diabetic rats and helped them maintain normal body weights. The glucose level in DC rats significantly increased while their body weights decreased. The 150 mg/kg bw dose significantly increased hexokinase and decreased G6Pase activities in the liver and the kidneys. ECA inhibited ${\alpha}-glucosidase$ activity and promoted glucose uptake in the rats' hemi-diaphragms. Conclusion: This study revealed that ECA normalized blood glucose levels and body weights in type 2 diabetic rats. The normalization of the glucose levels may possibly be due to inhibition of ${\alpha}-glucosidase$, decreased G6Pase activity, increased hexokinase activity and improved glucose uptake by muscle tissues.

• Journal of Nutrition and Health
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• v.46 no.5
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• pp.401-409
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• 2013

Smilax china L., a native plant found in Asian countries, has several medicinal properties including antioxidant, anti-inflammatory, and anti-cancer effects. Although the root of the plant is commonly used as traditional herbal medicine in Korea and China, the medicinal properties of the leaves have not gained the same attention. In this study, we analyzed the antioxidant activity, ${\alpha}$-glucosidase inhibitory effect and lipid accumulation inhibition effect of Smilax china L. leaf water extract (SCLE) and its solvent fractions. SCLE was fractionated by using a series of organic solvents, including ethylacetate (EA) and n-butanol (BuOH). The EA fraction had the highest total polyphenol content ($440.20{\pm}12.67$ mg GAE/g) and total flavonoid content ($215.14{\pm}24.83$ mg QE/g). The radical scavenging activity $IC_{50}$ values of the EA fraction for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) were 0.022 mg/mL and 0.13 mg/mL, respectively. Further, SOD-like activity and reducing power values of the EA fraction were higher than those of the other fractions. However, both the ${\alpha}$-glucosidase and lipid accumulation inhibition assays showed that the BuOH fraction ($83.35{\pm}4.18%$ at 1 mg/mL) and water extract ($11.27{\pm}2.67%$) were more effective than the EA fraction ($64.13{\pm}6.35%$, and $45.66{\pm}7.20%$). These results provide new insights into the potential anti-diabetic and anti-obesity effects of Smilax china L. leaf.

• Korean Journal of Food Science and Technology
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• v.44 no.3
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• pp.331-336
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• 2012

In this study, we selected Gardeniae fructus (GF) as an anti-inflammatory functional material and improved the biological activity of GF through the treatment of ${\beta}$-glucosidase. For the simple evaluation of anti-inflammatory activity, the inhibitory activity of GF extract (GFE) on the production of NO by RAW264.7 cells in the presence of LPS was examined. ${\beta}$-glucosidase originating from Aspergillus niger or Aspergillus fumigatus has effectively improved the anti-inflammatory activity of GFE. The enzyme treatment raised the activity of GFE by more than 10 times. The optimum conditions for the enzyme reaction were at pH 4.6, $45^{\circ}C$, and 20 U/mL for 24 h with agitation. In addition, in vitro production of cytokines (IL-$1{\beta}$, IL-6, TNF-${\alpha}$), COX-2, and the NF-${\kappa}B$ activation of RAW264.7 cells decreased more in the presence of GFE treated with ${\beta}$-glucosidase originating from Aspergillus niger (GFAN) than in the presence of GFE. These results suggest that enzyme-treated GFE might be a potential candidate for natural anti-inflammatory food materials.

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.622-628
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• 2014

The aim of this work is to evaluate the potential of oriental melon (Cucumis melo L. var. makuwa Makino) seeds for the management of type 2 diabetes by controlling glucose absorption. The ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory effects of the hexane extracts from oriental melon seeds were investigated. A bioassay-guided fractionation technique was used to elucidate the principal active components. The results show that the hexane extract from oriental melon seeds exhibited high inhibitory activities against ${\alpha}$-glucosidase and ${\alpha}$-amylase. The hexane extract was further fractionated into four sub-fractions. Among them, the sub-fraction F-1 exhibited the most potent anti-diabetic effect. The active components were isolated and identified by gas chromatography/mass spectroscopy (GC-MS). Free fatty acids showed significant hypoglycemic activity (p < 0.001) and fatty acid composition influenced enzyme inhibitory activities. These results suggest that oriental melon seeds could be used to prevent type 2 diabetes.