• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.111-116
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• 2008

Aralia elata seeds were successively extracted with water, methanol, ethanol, acetone and chloroform. The crude extracts were investigated for antioxidant and antidiabetic activities. The antioxidant properties of various extracts were evaluated by antioxidant tests, such as DPPH free radical-scavenging activity, hydroxyl radical-scavenging assay, metal-chelating activity, lipid peroxidation inhibition activity and reducing power assay. The 70% methanol extract exhibited the highest activity in the in vitro models of DPPH free radical-scavenging activity, metal-chelating activity, and reducing power assay. Acetone extract showed good effects on lipid peroxidation inhibition and hydroxyl radical-scavenging assay at a low concentration. In addition, the $\alpha$-glucosidase inhibition assay showed that 70% methanol extract had the highest activity. These results indicate the high possibility of using A. elata seeds for medical application due to their efficient antioxidant properties.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.389-393
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• 2001

An $\alpha$-glucosidase inhibitor, CK-4416, was identified from the culture broth of Streptomyces sp. CK-4416. CK-4416, which had some specificity against intestinal disaccharidases, especially sucrase and matlase activities, was purified by adsorption and cationic ion exchange chromatographies. The molecular formula was determined to be $C_{37}H_{63}NO_{30}$ (MW 1001.31) by FAB-MS and NMR analyses. In vitro studies found CK-4416 to show a potent inhibitory activity against sucrase and maltase, but it had low inhibition against $\alpha$-amylase.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.382-390
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• 2018

Background: The plant Aster koraiensis has long been used as an ingredient in folk medicine. It has been reported that Aster koraiensis extract (AKE) prevents the progression of diabetes-induced retinopathy and nephropathy. However, although these beneficial effects of AKE on diabetes complications have been identified, the antidiabetic effects of AKE have not yet been completely investigated and quantified. In the present study, the glucose-lowering and antioxidant effects of aqueous and ethanolic AKEs were evaluated. Methods and Results: The glucose-lowering effects of aqueous and ethanolic (30%-, 50%-, and 80%-ethanol) AKEs were investigated via ${\alpha}$-glucosidase inhibitory assays. The mode of inhibition by AKEs on ${\alpha}$-glucosidase was identified through kinetic analysis. The total antioxidant capacity of each of the 4 AKEs was evaluated by assessing their conversion rate of $Cu^{2+}$ to $Cu^+$. The content of chlorogenic acid and 3,5-di-O-caffeoylquinic acid, the bioactive compounds in AKE, in each extract were analyzed by high performance liquid chromatography (HPLC). The AKEs showed potent ${\alpha}$-glucosidase inhibitory activity with mixed inhibition mode, and significant antioxidant capacity. Conclusions: These results of this study suggested that the AKEs tested had ${\alpha}$-glucosidase inhibitory and antioxidant effects. Among the extracts, the 80% ethanol extract showed the most significant ${\alpha}$-glucosidase inhibitory activity, with a half maximal inhibitory concentration ($IC_{50}$ value) of $1.65{\pm}0.36mg/m{\ell}$ and a half maximal effective concentration ($EC_{50}$ value) for its antioxidant activity of $0.42{\pm}0.10mg/m{\ell}$. It can therefore be used as a source of therapeutic agents to treat diabetes patients.

• Food Science and Preservation
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• v.21 no.4
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• pp.460-467
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• 2014

This study was conducted to investigate the effect of the addition of Hizikia fusiforme, Capsosiphon fulvescens, and Undaria pinnatifida sporophyll on the antioxidant and inhibitory potentials against key enzymes related to type 2 diabetes of a commercial vegetable extract. The nutritional quality and mineral concentration of a vegetable extract with seaweeds added were also analyzed. The addition levels of seaweed did not influence the proximate composition, whereas the calcium, sodium, potassium, magnesium, and iron concentrations significantly increased at the 5% Hizikia fusiforme and Undaria pinnatifida sporophyll addition levels. The 20% Hizikia fusiforme addition level significantly increased the total phenolic content and reducing power by 47.08% and 16.82%. The hydroxyl radical scavenging ability of the vegetable extract was not strengthened with the addition of seaweeds. The DPPH radical scavenging activity at the 20% Hizikia fusiforme, Capsosiphon fulvescens, and Undaria pinnatifida sporophyll addition levels significantly increased by 27.47%, 22.25%, and 17.27%, respectively. The vegetable extract with seaweeds added showed higher-level ${\alpha}$-glucosidase inhibition activities, accompanied by relatively weaker ${\alpha}$-amylase inhibition activity. In particular, at the 5% Undaria pinnatifida sporophyll addition level, the ${\alpha}$-glucosidase activity was significantly inhibited by 98.26%. Overall, the results showed that the incorporation of seaweeds into a vegetable extract effectively increased the mineral concentration and improved the antioxidant and inhibitory abilities of the extract on key enzymes linked to type 2 diabetes.

• 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 Biotechnology
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• v.17 no.2
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• pp.302-307
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• 2008

Novel amylase inhibitors were synthesized via transglycosylation by Thermotoga maritima glucosidase (TMG). TMG hydrolyzes acarbose, acarviosine-glucose, and maltooligosaccharide by releasing $^{14}C$-labeled glucose from the reducing end of each molecule. When TMG was incubated with acarviosine-glucose (the donor) and glucose (the acceptor), two major transfer products, compounds 1 and 2, were formed via transglycosylation. The structures of the transfer products were determined using thin-layer chromatography (TLC), high-performance ion chromatography (HPIC), and $^{13}C$ nuclear magnetic resonance (NMR) spectroscopy. The results indicate that acarviosine was transferred to glucose at either C-6, to give a $\alpha-(1{\rightarrow}6$) glycosidic linkage, or at C-3, to produce an $\alpha-(1{\rightarrow}3$) glycosidic linkage. The transfer products showed a mixed-type inhibition against porcine pancreatic $\alpha$-amylase; therefore, they may be useful not only as inhibitors but also as acarbose transition-state analogs to study the mechanism of amylase inhibition.

• 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 Applied Biological Chemistry
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• v.57 no.2
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• pp.179-182
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• 2014

In the present study, we investigated the effects of methanol extracts from Alpinia katsumadai Hayata against antiviral potential underlying mechanism in glucosidase inhibition. Syncytium formation in Newcastle disease virus (NDV)-infected baby hamster kidney (BHK) cell originates from the trafficking of viral glycoprotein into cell-surface. Methanol extracts inhibited not only syncytium formation, but also trafficking of glycoprotein, hemagglutinin-neuraminidase (HN), onto cell-surface. A. katsumadai extracts showed the inhibitory activities ($IC_{50}$ $25{\mu}g/mL$) against ${\alpha}$-glucosidase. These results suggested that blue chanterelle extracts inhibited the cell-surface expression of NDV-HN glycoprotein without significantly affecting HN glycoprotein synthesis in NDV-infected BHK cells.

• 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 Plant Resources
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• v.25 no.2
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• pp.169-175
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• 2012

For the elucidation of action mechanism on anti-HIV of natural resources, the extracts of $Campsis$ $grandiflora$ were tested for their inhibitory effects on HIV-1 replication and its essential enzymes as the reverse transcriptase (RT), protease and ${\alpha}$-glucosidase. In the assay of HIV-1-infected human T-cell line, water extracts of stem inhibited the HIV-1-induced cytopathic effects with IC (inhibitory concentration) of 100 ${\mu}g$/ml. Moreover water extracts (100 ${\mu}g$/ml) of stem showed strong activity of 37.9% on anti-HIV-1 RT using Enzyme Linked Oligonucleotide Sorbent Assay (ELOSA) method. In the HIV-1 protease inhibition assay, methanol extracts of stem and leaf extract showed 33.6% and 31.5% inhibition of the enzyme activity to cleave an oligopeptide resembling one of the cleavage sites in the viral polyprotein which can only be processed by HIV-1 protease, but did not exhibited glucosidase inhibitory activities. From these results, it is suggested that the inhibition of the viral replication $in$ $vitro$ is due to the inhibition of reverse transcriptase by water extracts of stem of $Campsis$ $grandiflora$.