• Journal of Applied Biological Chemistry
• /
• v.43 no.3
• /
• pp.141-146
• /
• 2000

Glycosidase activities were tested from the grape berries, Vitis labruscana B. Takasumi. Among various glycosidases, $\alpha$-D-galactosidase was found to be the most active in the flesh and other glycosidases were considerably active in the order of the following: $\alpha$-D-mannosidase>$\alpha$-D-glucosidase>$\beta$-D-glucosidase>$\beta$-D-galactosidase. In the seeds, $\alpha$-D-glucosidase activity was the highest and other glycosidases such as $\alpha$-D-galactosidase, $\beta$-D-glucosidase, and $\beta$-D-galactosidase were still significantly active. The $\alpha$-D-galactosidase in the grape flesh was purified over 83-folds through salting-out with $(NH_4)_2SO_4$ and a series of chromatographies employing Sephadex G-50, Octyl-Sepharose, Q-Sepha- rose, and Biogel P-100. The enzyme was a monomer of 45 kDs as determined through SDS-PAGE and Sephacryl S-200 chromatography. The purified enzyme showed a preference of $\alpha$-D-galactose to $\beta$-D-galactose as a substrate about 5.4 times. Sulfhydryl specific reagents such as N-ethylmaleimide and iodoacetamide significantly inhibited the enzyme activity to the extents of 48 and 52% of its initial activity, respectively. The optimumpH range of $\alpha$-D-galactosidase was around 6.5-7.0. The enzyme activity increased by 46% in the presence of 1mM $Fe^{2+}$.

• Microbiology and Biotechnology Letters
• /
• v.37 no.2
• /
• pp.99-104
• /
• 2009

The $\beta$-glucosidase gene from Streptomyces coelicolor A3(2) was cloned and expressed in Escherichia coli. The ORF consisted of 1377 nucleotides encoding 51 kDa in a predicted molecular weight. Effects of pH indicated that the $\beta$-glucosidase showed similar activity using $\alpha$-pNPG($\rho$-nitrophenyl-$\alpha$-D-glucopyranoside), $\beta$-pNPG($\rho$-nitrophenyl-$\beta$-D-glucopyranoside), and $\beta$-pNPF($\rho$-nitrophenyl-$\beta$-D-fucopyranoside) at range of pH 3 to 10, and high activity using $\beta$-pNPGA ($\rho$-nitrophenyl-$\beta$-D-galactopyranoside) from pH 5 to 10, especially, 3.3 times higher activity at pH 9. Effects of temperature indicated that the $\beta$-glucosidase showed low activity using $\alpha$-pNPG, $\beta$-pNPG, and $\beta$-pNPF from $20^{\circ}C$ to $70^{\circ}C$, and increased activity using $\beta$-pNPGA from $30^{\circ}C$ to $50^{\circ}C$, 1.8 times higher activity at $50^{\circ}C$ than at $30^{\circ}C$. According to activity determination of other substrates, the enzyme was active on daidzin, genistin, and glycitin, inactive on esculin and apigenin-7-glucose. The EDTA and DTT as reducing agents inhibited $\beta$-glucosidase activity, but SDS and mercaptoethanol did not inhibit. Monovalent or divalent metal ions such as $MnSO_4$, $CaCl_2$, KCl, and $MgSO_4$ did not inhibited $\beta$-glucosidase activity. $CuSO_4$ and NaCl showed low inhibition, and $ZnSO_4$ inhibited 3.3 times higher than control.

• Microbiology and Biotechnology Letters
• /
• v.37 no.3
• /
• pp.204-212
• /
• 2009

A strain producing ${\alpha}$-galactosidase and ${\beta}$-glucosidase was isolated from Kimchi. The isolated strain was identified as Weissella cibaria by 16S rDNA analysis and designated as Weissella cibaria K-M1-4. The enzyme activity of ${\alpha}$-galactosidase and ${\beta}$-glucosidase reached the maximum in the soy medium at $37^{\circ}C$ for 24 hr. The enzymes were purified by ethanol fractionation, DEAE sepharose fast flow, and sephacryl S-100HR column chromatography. ${\alpha}$-Galactosidase specific activity was shown by 576 Units/mg protein and the yield was 3.5% of the total activity of crude extracts. ${\beta}$-glucosidase specific activity was shown by 480 Units/mg protein and the yield was 2.9% of the total activity of crude extracts. The optimum temperature for ${\alpha}$-galactosidase was $60^{\circ}C$ and 43% of its original activity remained when it was treated at $80^{\circ}C$ for 30 min. For ${\alpha}$-galactosidase shows the optimum pH of 8.0 and is fairly stable between pH5.0 and pH9.0. The enzyme activity was increased in the presence of $Fe^{2+}$ and $Cu^{2+}$. The value of Km and Vmax for the enzyme were 0.98 mM and $1.81{\mu}$mole/min, respectively. The ${\beta}$-glucosidase has the optimum temperature of $50^{\circ}C$ and 46% of its original activity remained when it was treated at $80^{\circ}C$ for 30min. Its optimum pH of 7.0 and is fairly stable between pH5.0 and pH9.0. The enzyme activity was increased in the presence of $Fe^{2+},\;Co^{2+}$ and $Cu^{2+}$. The value of Km and Vmax for the enzyme were 1.24 mM and $6.81{\mu}$mole/min, respectively.

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

• Mycobiology
• /
• v.40 no.3
• /
• pp.173-180
• /
• 2012

A ${\beta}$-glucosidase from Penicillium italicum was purified with a specific activity of 61.8 U/mg, using a chromatography system. The native form of the enzyme was an 88.5-kDa tetramer with a molecular mass of 354 kDa. Optimum activity was observed at pH 4.5 and $60^{\circ}C$, and the half-lives were 1,737, 330, 34, and 1 hr at 50, 55, 60, and $65^{\circ}C$, respectively. Its activity was inhibited by 47% by 5 mM $Ni^{2+}$. The enzyme exhibited hydrolytic activity for p-nitrophenyl-${\beta}$-D-glucopyranoside (pNP-Glu), p-nitrophenyl-${\beta}$-D-cellobioside, p-nitrophenyl-${\beta}$-D-xyloside, and cellobiose, however, no activity was observed for p-nitrophenyl-${\beta}$-D-lactopyranoside, p-nitrophenyl-${\beta}$-D-galactopyranoside, carboxymetyl cellulose, xylan, and cellulose, indicating that the enzyme was a ${\beta}$-glucosidase. The $k_{cat}/K_m\;(s^{-1}mM^{-1})$ values for pNP-Glu and cellobiose were 15,770.4 mM and 6,361.4 mM, respectively. These values were the highest reported for ${\beta}$-glucosidases. Non-competitive inhibition of the enzyme by both glucose ($K_i=8.9mM$) and glucono-${\delta}$-lactone ($K_i=11.3mM$) was observed when pNP-Glu was used as the substrate. This is the first report of non-competitive inhibition of ${\beta}$-glucosidase by glucose and glucono-${\delta}$-lactone.

• Journal of Life Science
• /
• v.21 no.11
• /
• pp.1579-1585
• /
• 2011

Natural anti-diabetic semipurified ethyl acetate fraction was isolated from the submerged-liquid culture of Agaricus blaze Murill (AB) in a medium containing soybean flakes. Hot-water extract of AB (HEAB) was prepared by extraction at $121^{\circ}C$ for 60 min, followed by filtering through a filter presser filled with diatomate. The ${\beta}$-glucan-free HEAB, which was a supernatant fraction from HEAB by precipitation in an 80% ethanol solution, was fractionated into hexane, chloroform, ethyl acetate, and butanol fractions. The inhibition of the ${\alpha}$-glucosidase activity by fractions was 59.0, 17.0, 61.6, and 37.9%, respectively, suggesting that ethyl acetate fraction was the most active. A subfraction having a strong ${\alpha}$-glucosidase inhibitory activity (80.4%) was isolated from the ethyl acetate fraction. This subfraction contained isoflavones (genistin and daidzin) and their conjugates with sugars as potent inhibiters of ${\alpha}$-glucosidase activity. These results suggest that the ethyl acetate fraction or HEAB containing isoflavones and their sugars conjugates could be useful sources for controlling blood sugar levels in humans.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.12
• /
• pp.1858-1864
• /
• 2014

In the present investigation, the anti-diabetic potential of 80% ethanol extract of Eleutherococcus senticosus leaves (EEES) was examined based on ${\alpha}$-glucosidase inhibitory activities. EEES was sequentially fractionated with n-hexane, chloroform, ethyl acetate (EtAOc), n-butanol, and $H_2O$. Of the various fractions, EtAOc fraction effectively inhibited ${\alpha}$-glucosidase activity by 68.05%. Therefore, EtAOc fraction was selected for further isolation and identification studies. EtAOc fraction was separated by medium pressure liquid chromatography with silica and ODS gel to yield eight fractions (EAA~EAH). Based on the results of ${\alpha}$-glucosidase inhibitory activity, EAH fraction was re-chromatographed to yielded four more fractions (EAHA~EAHD). Of these, EAHC fraction showed higher ${\alpha}$-glucosidase inhibitory activity of 93.60%. EAHC fraction was re-chromatographed and yielded EAHCA and EAHCB fractions. Further, identification and chemical structures of these two fractions were analyzed using $^1H$-NMR, $^{13}C$-NMR, and mass spectra data. Based on the results of the spectral data, the isolated compounds were identified as hyperoside and isoquercetin. Results of the present study indicate that the isolated compounds, hyperoside, and isoquercetin from leaves of E. senticosus could be used for the development of new anti-diabetic drugs.

• Horticultural Science & Technology
• /
• v.28 no.5
• /
• pp.857-863
• /
• 2010

This study was conducted to evaluate the antioxidant activity, Angiotensin I Converting Enzyme (ACE) inhibitory activity, ${\alpha}$-glucosidase inhibitory activity, nitrate synthesis inhibitory activity, and antiproliferation inhibitory effect on ethanol extract and its solvent fractions of $Coreopsis$ $tinctoria$ Nutt. Ethyl acetate fraction was the strongest at 1,1-diphenyl-2-picryl hydrazyl (DPPH) ($IC_{50}=0.100mg{\cdot}mL^{-1}$) and 2,2'-Azino-bis-(3-ethylbenozothiazoline-6-sulfonic acid) (ABTS) (15.785 mg AA $eq{\cdot}10mg^{-1}$) radical scavenging activity, ACE (40.96% at $1mg{\cdot}mL^{-1}$), and ${\alpha}$-glucosidase ($IC_{50}=0.125mg{\cdot}mL^{-1}$) inhibitory effect among the solvent fractions. Nitrate synthesis inhibitory activity of ethanol extract, chloroform fraction, and ethyl acetate fraction effectively inhibited NO formation in a dose-dependent manner without the cytotoxic effect. Ethanol extract and its solvent fractions inhibited growth of HCT-116 colon cancer cells in a dose-dependent manner. n-Hexane fraction showed the highest antiproliferation inhibitory effect of $0.041mg{\cdot}mL^{-1}$ among fractions.

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

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