• Journal of Applied Biological Chemistry
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• v.60 no.3
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• pp.241-244
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• 2017

The antioxidant activity of various solvent extracts from Jeju camellia mistletoe (Korthalsella japonica (Thunb.) Engl.) was investigated using various in vitro assays as the 1,1-diphenyl-2-picrylhydrazyl radical scavenging, ferrous ion chelating and reducing power assays. Methanol and ethanol extracts showed the most potent antioxidant activity in all assays tested followed by water extract. The inhibitory effect of the Jeju camellia mistletoe extracts on pancreatic lipase and $\acute{a}$-glucosidase was also evaluated and the results showed that methanol and ethanol extracts markedly reduced both enzyme activities. Therefore, the methanol and ethanol extracts of Jeju camellia mistletoe is definitely worthy of further investigation for these beneficial effects on nutraceutical medicine.

• Food Science and Preservation
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• v.23 no.2
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• pp.239-245
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• 2016

This study was conducted to compare the functionality (antioxidant, anti-diabetic, and anti-dementia activities) of the methanol extract of Allium hookeri root grown in Korea (KR) and Myanmar (MR). The total polyphenol and flavonoid contents of KR and MR were 5.27 and 4.80 mg GAE/g, and 0.35 and 0.24 mg QE/g, respectively. KR contained significantly higher levels of total polyphenols and total flavonoids than those of MR (p<0.05). The IC50 values of KR and MR were 6.53 and 5.31 mg/mL, respectively, for DPPH radical scavenging activity. However, KR had a significantly higher ABTS radical scavenging activity, $Fe^{2+}$ chelating ability, and reducing power compared with those of MR (p<0.05). In the evaluation of anti-diabetic activity, KR showed significantly higher ${\alpha}-glucosidase$ inhibition activity than acarbose and MR at whole concentrations (p<0.05). KR and MR had acetylcholinesterase inhibition activities that of 51.44% and 44.33%, respectively, at a 50 mg/mL concentration. These results suggested that roots of A. hookeri, especially KR, could be useful in improving diabetic and dementia disorders due to their high antioxidant, anti-diabetic, and anti-dementia activities.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.246-252
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• 2012

After a mixed carbohydrate diet, inhibition of ${\alpha}$-amylase and ${\alpha}$-glucosidase involved in the digestion and absorption of carbohydrates can significantly decrease the postprandial increase of blood glucose level. In the course of screening these useful enzyme inhibitors, we selected five kinds of bean, using an in-vitro enzyme inhibition assay method. To evaluate the effect of germination process on the functionality of the bean, we investigated the inhibitory activities of the water extracts of non-germinated bean and germinated bean against ${\alpha}$-amylase and ${\alpha}$-glucosidase, relevant to postprandial hyperglycemia. We also investigated the oxygen radical absorbance capacity(ORAC), total phenolics content, and postprandial blood glucose lowering effect in rats(Sprague-Dawley rat model). Most germinated beans showed significantly higher ${\alpha}$-glucosidase inhibitory activity, compared with non-germinated beans. Among germinated beans, Glycine max had the highest ${\alpha}$-glucosidase inhibitory activity(53.3%). The water extract of germinated Phaseolus vulgaris L. had the highest ${\alpha}$-amylase inhibitory activity(95.1%), followed by Glycine max(58.7%), and Glycine max L. Merr(54.1%). Furthermore, the five germinated beans also showed high antioxidant activities in ORAC assay. Results suggested that the germination process may improve and enhance the anti-hyperglycemia potential and antioxidant activity of the bean.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.30-35
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• 2010

The potential biological activities of methanol extract and 5 fractions (hexane, $CH_2Cl_2$, EtOAc, BuOH and water) from roots of Astragalus membranaceus were examined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, hydroxyl radical (${\cdot}OH$) scavenging activity, reducing power assays, lipid peroxidation inhibitory activity, $\alpha$-amylase and $\alpha$-glucosidase inhibition assays. The EtOAc fraction showed high DPPH free radical scavenging activity ($EC_{50}=170.34\;{\mu}g/mL$), hydroxyl radical scavenging activity ($EC_{50}=32.14\;{\mu}g/mL$), lipid peroxidation inhibitory activity ($EC_{50}=52.46\;{\mu}g/mL$) and a concentration dependence, with OD value ranging from 0.234 to 0.345 (0.1 to 0.5 mg/mL), for reducing power. The EtOAc fraction has the highest total phenolic content ($142.13\;Gal\;{\mu}g/mg$) and the $CH_2Cl_2$ fraction has the highest flavonoid content ($71.63\;Que\;{\mu}g/mg$). Meanwhile, hexane and EtOAc showed certain $\alpha$-amylase and $\alpha$-glucosidase inhibition activities. These results suggest that the methanol extract and fractions from Astragalus membranaceus root have significant antioxidant and anti-diabetes activities, which could be used as a potential source of pharmaceutical materials.

• Korean Journal of Pharmacognosy
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• v.42 no.1
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• pp.61-67
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• 2011

In this study, we evaluated the bioactivities of methanol extract and its solvent fractions of Sonchus asper (L.) Hill. The EtOAc fraction of S. asper exhibited more strong antioxidant activity than other extracts as evidenced by the strongest 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity with a $EC_{50}$ value at $33.55\;{\mu}g/mL$ and reducing power, the total polyphenol (180.71 mg GAE/g) and flavonoid contents (145.86 mg QE/g) of S. asper extract were higher than other extracts. The EtOAc fraction of the S. asper also showed 47.38% mushroom tyrosinase inhibition activity, 56.22% ${\alpha}$-glucosidase inhibition and 46.58% ${\alpha}$-amylase inhibition ratio at 1 mg/mL. Both methylene chloride and EtOAc fractions of methanol extract of S. asper effectively reduced of the 86.34% and 62.03% angiotensin I converting enzyme (ACE) activity at 2 mg/mL, respectively. These findings suggest that the EtOAc fraction of the S. asper could be a potential antioxidant in food additive, medicinal, and industry product.

• Food Science and Preservation
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• v.21 no.3
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• pp.396-403
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• 2014

In this study, the antioxidant effect of water and ethanol extracts from Juniperus rigida Sieb were investigated. The activities of each of the extracts were measured based on their total phenolic and flavonoid contents and using antioxidant test such as of 2,2-azinobis (3-ethyl benzothiazoline-6-sulfonic acid (ABTs) radical scavenging activities, ferric reducing antioxidant power (FRAP), angiotensin I converting enzyme (ACE) inhibition activity, antioxidant protection fator (PF), thiobarbituric acid reactive substances (TBARs) content, and ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibition activity assay. The result of the examination to measure the polyphenol content by investigating the antioxidativity of the J. rigida Sieb. extract showed 71.3 mg/g polyphenol content in the water extract, and 116.0 mg/g in the ethanol extract and a 17.7 mg/g flavonoid content in the water extract and in 76.4 mg/g in the ethanol extract. The ABTS radical cation decolorization showed 76.4% and 79.3% scavenging activities of the $500{\mu}g/mL$ water extract and ethanol extract, respectively. The FRAP showed 1.83 mM efficacy in the water extract and a lower 1.77 mM in ethanol extract. Both the water extract and the ethanol extract showed reduced ACE activities of 75.39% and 71.25% at $500{\mu}g/mL$, respectively. The antioxidant protection factor of the water and 70% ethanol extracts of J. rigida Sieb were 1.5 PF and 2.1 PF, respectively. In the TBARS inhibitory activity, the extracts showed 55.78% and 71.48% antioxidant activities at the $500{\mu}g/mL$ concentration. The results of the measurrement of the ${\alpha}$-amylase inhibitory activity indicated more than 90% of activity inhibition in the $500{\mu}g/mL$ concentration of the ethanol extract. For the ${\alpha}$-glucosidase inhibitory activity, the ethanol extract showed 70% activity inhibition at the $500{\mu}g/mL$ concentration.

• 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.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 Dietetic Association
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• v.25 no.4
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• pp.281-294
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• 2019

The objective of this study was to develop fermented vegetable juices that possess antidiabetic and antioxidant activities. Lactobacillus plantarum MKHA15 (MKHA15) and Leuconostoc mesenteroides MKSR (MKSR) were applied to ferment onion, cabbage, and tomato juices at $37^{\circ}C$ and $30^{\circ}C$ for 72 h, respectively, and their functionality was tested using the 12 h hour-fermented juice by MKHA15, and 48 h hour-fermented juice by MKSR. Inhibition of ${\alpha}$-glucosidase activity was observed in all fermented juices. The onion juice fermented by MKHA15 showed significantly higher ${\alpha}$-glucosidase inhibition activity compared to other juices. All juices showed more than 70% inhibition of ${\alpha}$-amylase activity. The DPPH radical scavenging activity of onion juice fermented by MKSR showed significantly lower activity than cabbage and tomato juices; however, no difference was observed between the types of starter cultures. The SOD-like activity of cabbage juice fermented by MKSR was the highest among the fermented juices. The juices fermented by MKHA15 showed higher reducing power than those by MKSR. Therefore, we believe that cabbage, onion and tomato juice fermented by MKHA15 and MKSR would be useful in probiotic juices, as they possess antidiabetic and antioxidant activities.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.82-85
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• 2006

Eucommia ulmoides bark extracts by cold water, boiling water, 100% EtOH, 70% EtOH, 100% MeOH, 70% MeOH and $CHCl_3$ were assayed for their medicinal effects. The antioxidant activity of the extracts ranged from $IC_{50}$ 125.2 to $IC_{50}\;872.7{\mu}g/ml$ in the 1,1-diphenyl-2-picrylhydrazyl (DDPH) free radical-scavenging assay, and cold water extracts had the highest antioxidant activity. $CHCl_3$ extracts had the highest inhibitory effect on angiotensin I-converting enzyme (ACE) giving inhibition of up to 56.4% at a concentration of 1 mg/ml. Extracts in 100% EtOH had the greatest inhibitory effect on $\acute{a}-amylase$ activity ($IC_{50}=174.6{\mu}g/ml$), and 70% MeOH extracts had the greatest inhibitory effect on ${\alpha}-glucosidase$ activity ($IC_{50}=14.0{\mu}g/ml$). Taken together, these results provided the in vitro evidence on the ACE, amylase and glucosidase inhibitory actions of E. ulmoides bark that form the pharmacological basis for its antihypertensive and antidiabetic action.