• Korean Journal of Medicinal Crop Science
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• v.22 no.4
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• pp.289-294
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• 2014

Maesa japonica (Thunb.) is an evergreen shrub belonged to the Myrsinaceae family, which was discovered in 2006 in South Korea. And, its biological functions have not been well studied. In this study, we determined the antioxidant activities, ${\alpha}$-glucosidase inhibitory effects and antimicrobial activities of methanol extract and the solvent fractions of M. japonica leaves and twigs. The highest antioxidant activity obtained by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay and reducing power assay was found in the ethylacetate fraction of twigs methanol extract, which contained the highest level of total phenolic compounds compared to the other fractions. In addition, ethylacetate fraction of twigs extract exhibited higher inhibitory activities against ${\alpha}$-glucosidase ($IC_{50}=0.8{\mu}g/m{\ell}$) compared to the $IC_{50}$ of the buthanol fraction ($IC_{50}=16{\mu}g/m{\ell}$) of leaves extract. It showed antimicrobial activities against Bacillus atrophaeus and Bacillus subtilis subsp. Spizizenii. Although the data is too limited, the current study is the first report on biological functions of M. japonica.

• Biomolecules & Therapeutics
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• v.6 no.4
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• pp.364-370
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• 1998

Glycosidase inhibitors from urine of Bombyx mori were isolated and their inhibitory activities on glycosidases were evaluated. Six compounds were isolated by using several ion exchange columns, and their chemical structures were identified by the physicochemical and spectral data. Compound IV, V and Ⅵ were identified as 1-deoxynojirimycin, fagomine and 1,4-dideoxy-1,4-imino-D-arabinitol, respectively. Among six compounds isolated,1-deoxynojirimycin(IV) was the most potent inhibitor on $\alpha$-glucosidase and $\beta$-galactosidase of rat intestine, and its inhibitory activities for trehalase and almond $\beta$-glucosidase were relatively weak. Compound V and Ⅵl retained a little inhibitory potency toward $\alpha$-glucosidase and $\beta$-galactosidase. Compound II and III, however, have been found to have no effect on all glycosidases tested in this study.

• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.311-315
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• 2017

${\alpha}$-glucosidase inhibitory compounds (1-4) in a 50% methanol extract of Euonymus alatus were isolated by activity-based fractionations and the structures determined on the basis of chemical and spectral characterization techniques such as $^1H$ and $^{13}C$ nuclear magnetic resonance spectroscopy, $^1H-^1H$ correlation spectroscopy (COSY), and heteronuclear multiple bond correlation (HMBC). The compounds 1-4 belong to flavonols and exhibited potent inhibitory activities against ${\alpha}$-glucosidase, with $IC_{50}$ values of 25.3, 17.1, 47.3, and $35.1{\mu}M$, respectively. All the isolated compounds were more potent than the positive control acarbose. This is the first report describing the potential hypoglycemic effect of Euonymus alatus through ${\alpha}$-glucosidase inhibition and identification of its active components.

• Korean Journal of Environmental Agriculture
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• v.34 no.1
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• pp.57-63
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• 2015

BACKGROUND: Momordica charantia (MC) have been used in various parts of the world to treat diabetes. Despite the highest effects of phytochemicals than any other part of the plant, the main components of seed of MC grown in Korea and their properties have not been studied extensively. METHODS AND RESULTS: The seeds of MC were extracted into five different polarity solvents: 30%, 50%, 70%, 95% ethanol and distilled water. The 95% ethanol extract showed the most potent inhibition ($IC_{50}=88.7{\mu}g/mL$) against ${\alpha}$-glucosidase. To investigate the compounds responsible for this effect, activity guided fractionation of MC seeds by chromatography yielded two phytochemicals which were confirmed as vicine (1) and ${\alpha}$-eleostearic acid (2) based on their NMR and ESI-MS spectroscopic data. Among them, ${\alpha}$-eleostearic acid (2) possessed potent ${\alpha}$-glucosidase inhibitory activities with $IC_{50}$ values from $32.4{\mu}g/mL$. CONCLUSION: Collectively, the results from this present study strongly suggest that both extract and ${\alpha}$-eleostearic acid (2) have potent ${\alpha}$-glucosidase inhibitory activity. Furthermore, ${\alpha}$-eleostearic acid (2) as the most active ${\alpha}$-glucosidase inhibitor was proven to be present in high quantities in the MC seeds by a HPLC chromatogram.

• Preventive Nutrition and Food Science
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• v.21 no.3
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• pp.181-186
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• 2016

This study was designed to investigate the inhibitory effect of Gynura procumbens extract against carbohydrate digesting enzymes and its ability to ameliorate postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. G. procumbens extract showed prominent ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory effects. The half-maximal inhibitory concentration ($IC_{50}$) of G. procumbens extract against ${\alpha}$-glucosidase and ${\alpha}$-amylase was $0.092{\pm}0.018$ and $0.084{\pm}0.027mg/mL$, respectively, suggesting that the ${\alpha}$-amylase inhibition activity of the G. procumbens extract was more effective than that of the positive control, acarbose ($IC_{50}=0.164mg/mL$). The increase in postprandial blood glucose levels was more significantly alleviated in the G. procumbens extract group than in the control group of STZ-induced diabetic mice. Moreover, the area under the curve significantly decreased with G. procumbens extract administration in STZ-induced diabetic mice. These results suggest that G. procumbens extract may help alleviate postprandial hyperglycemia by inhibiting carbohydrate digesting enzymes.

• Journal of Life Science
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• v.18 no.7
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• pp.1005-1010
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• 2008

In this study, we investigated the inhibitory effect of four solvent fractions of Alnus firma on ${\alpha}-amylase$, ${\alpha}-glucosidase$ and aldose reductase activities. The inhibitory test showed that methanol (MeOH) extract and hexane (HX) fraction strongly inhibited pork pancreatin and salivary ${\alpha}-amylase$ activity. The MeOH extract and HX fraction of Alnus firma at the concentration of 4 mg/ml inhibited more than 70% of pancreatin and salivary ${\alpha}-amylase$ activity. The inhibitory effect of fractions has different specificities against ${\alpha}-amylase$ from pancreatin and salivary. In addition, the MeOH extract and butanol (BuOH) fraction showed the highest inhibitory activity on yeast ${\alpha}-glucosidase$ at values of $IC_{50}$ $137.36\;{\mu}g/ml$ and $115.14\;{\mu}g/ml$ respectively. The MeOH extract and BuOH fraction showed the highest inhibitory activity on yeast ${\alpha}-glucosidase$ than commercial agent such as 1-deoxynorjirimycin and acarbose. Inhibition kinetics of solvent fractions showed that ${\alpha}-glucosidase$ has been inhibited noncompetitively by the MeOH, EA and BuOH fraction. The aldose reductase from human muscle cell had been inhibited strongly by the MeOH extract and EA fraction at 57.996% and 83.293% at the concentration of $50\;{\mu}g/ml$, respectively. These findings may contribute to biological significance in that ${\alpha}-amylase$, ${\alpha}-glucosidase$ and aldose reductase inhibitory compounds could be used as a functional food and a drug for the symptomatic treatment of antidiabetic disease in the future.

• Culinary science and hospitality research
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• v.18 no.5
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• pp.233-242
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• 2012

Jehotang is a cold traditional Korean drink made with honey and several ingredients used in traditional Korean medicine. The ingredients include Fructus mume, Fructus amomi, Fructus tsaoko, Santalum album and honey. In this study, Jehotang and its ingredients were determined through the analysis of antioxidant activity, total phenolic content, ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory activity. In addition, quality characteristics of Jehotang made by a traditional recipe(Yeonmil) and a modern recipe(double boiling and boiling) were also compared in terms of pH, color and sugar content. Total phenolic content of extract from Fructus ammomi was found to be 120.45 mg, and Yeonmil recipe was discovered 152.66 mg equivalent of gallic acid per g of extract. DPPH free radical scavenging activity were Feuctus amomi(93.13%) and Yeonmil recipe(56.44%). The Fructus amomi extract showed the highest ${\alpha}$-glucosidase inhibitory activity(89.51%) at the concentration of $100{\mu}g/mL$. ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory activity of boiled Jehotang were 52.38% and 72.52%, respectively. These results suggest that extract of Fructus amomi has an antioxidant activity and antidiabetic effects. Yeonmil recipe is useful for antioxidant effects more than the others. Also, the double boiling recipe has an excellent antidiabetic effect.

• 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.

• Korean Journal of Pharmacognosy
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• v.31 no.3
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• pp.268-272
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• 2000

GE974, isolated from Gyrophora esculenta, showed significant inhibitory effect on several ${\alpha}-glucosidases$ in vitro in previous study. In the present study, GE974 showed significant inhibitory effect on blood glucose elevation in mice loaded with maltose, sucrose, starch and lactose. Also, it exhibited similar effect in alloxan and streptozotocin induced diabetic mice, and genetic diabetic mice(db/db mice) loaded with maltose in dose dependent manner. These results suggest that GE974 may possess hypoglycemic effect that inhibit competitively ${\alpha}-glucosidase$ activities.

• 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.