• Title, Summary, Keyword: ${\alpha}$-glucosidase

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Purification and Characterization of a Bacillus sp. DG0303 Thermostable $\alpha$-Glucosidase with Oligo-l,6-glucosidase Activity

  • Park, Jong-Sung;Kim, Il-Han;Lee, Yong-Eok
    • Journal of Microbiology and Biotechnology
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    • v.8 no.3
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    • pp.270-276
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    • 1998
  • Extracellular ${\alpha}$-glucosidase was purified to homogeneity from moderately thermophilic Bacillus sp. DG0303. The thermostable ${\alpha}$-glucosidase was purified by ammonium sulfate fractionation, ion-exchange chromatography, preparative polyacrylamide gel electrophoresis (PAGE), and electroelution. The molecular weight of the enzyme was estimated to be 60 kDa by SDS-PAGE. The optimum temperature for the action of the enzyme was at $60^{\circ}C$. It had a half-life of 35 min at $60^{\circ}C$. The enzyme was stable at the pH range of 4.5~7.0 and had an optimum pH at 5.0. The enzyme preparation did not require any metal ion for activity. The thermostable ${\alpha}$-glucosidase hydrolyzed the ${\alpha}$-1,6-linkages in isomaltose, isomaltotriose, and panose, and had little or no activity with maltooligosaccharides and other polysaccharides. The $K_m$ (mM) for p-nitrophenyl-${\alpha}$-D-glucopyranoside (pNPG), panose, isomaltose, and isomaltotriose were 4.6, 4.7, 40.8, and 3.7 and the $V_{max}$(${\mu}mol{\cdot}min^-1$$mg^-1$) for those substrates were 5629, 1669, 3410, and 1827, respectively. The N-terminal amino acid sequence of the enzyme was MERVWWKKAV. Based on its substrate specificity and catalytic properties, the enzyme has been assigned to be an oligo-1,6-glucosidase.

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Hypoglycemic Effect of the Methanol Extract of Soybean Sprout in Streptozotocin-Induced Diabetic Rats (Streptozotocin 유발 당뇨쥐에 있어서 콩나물 메탄올 추출물의 헐당강하효과)

  • 김정인;강민정;배세연
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.6
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    • pp.921-925
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    • 2003
  • To control blood glucose level as close to normal is the major goal of treatment of diabetes mellitus. $\alpha$-glucosidase is the enzyme to digest dietary carbohydrate and inhibition of $\alpha$-glucosidase could suppress postprandial hyperglycemia. The methanol extract of soybean sprout was tested for the inhibitory activities against $\alpha$-glucosidase in vitro. Soybean sprout extract inhibited yeast $\alpha$-glucosidase activity by 24.5% at the concentration of 5 mg/mL. The methanol extract of soybean sprout was subsequently subjected to sequential fractionation with hexane, ethyl acetate, butanol and water. Among the fractions tested ethyl acetate-soluble fraction showed relatively strong inhibition against $\alpha$-glucosidase by 36.3% at the concentration of 5 mg/mL. Acarbose, standard $\alpha$-glucosidase inhibitor, inhibited $\alpha$-glucosidase activity by 40.1%. The ability of soybean sprout extract to lower postprandial glucose was studied in streptozotocin-induced diabetic rats. Starch solution (1 g/kg) with and without the methanol extract of soybean sprout (500 mg/kg) was administered to diabetic rats after an overnight-fast by gastric intubation. A single oral dose of soybean sprout extract inhibited the increase in blood glucose levels significantly at 60, 90, 120, 180 min (p<0.05) and decreased incremental response areas under the glycemic response curve significantly (p<0.05). These results suggest that soybean sprout might exert hypoglycemic effect by inhibiting $\alpha$-glucosidase activity.

Isolation and Characterization of $\alpha$-Glucosidase Inhibitor from the Fungus Ganoderma lucidum

  • Kim, Shin-Duk;Nho, Hong Joon
    • Journal of Microbiology
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    • v.42 no.3
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    • pp.223-227
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    • 2004
  • An ${\alpha}$-glucosidase inhibitor, SKG-3, was isolated from the fruiting bodies of Ganoderma lucidum and its physico-chemical properties were characterized. It was a highly specific and effective reversible inhibitor of ${\alpha}$-glucosidase. It showed very potent inhibitory activity against a-glucosidase with an IC$\sub$50/ value of 4.6$\mu\textrm{g}$/$m\ell$, but no activity for any other glycosidases tested. Enzyme activity could be recovered upon dialysis, thus providing evidence for the reversibility of the inhibition. A Lineweaver-Burk plot indicated that the SKG-3 inhibition of ${\alpha}$-glucosidase was competitive.

Fermentation of purple Jerusalem artichoke extract to improve the α-glucosidase inhibitory effect in vitro and ameliorate blood glucose in db/db mice

  • Wang, Zhiqiang;Hwang, Seung Hwan;Lee, Sun Youb;Lim, Soon Sung
    • Nutrition Research and Practice
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    • v.10 no.3
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    • pp.282-287
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    • 2016
  • BACKGROUND/OBJECTIVES: Jerusalem artichoke has inhibitory activity against ${\alpha}$-glucosidase and decreases fasting serum glucose levels, which may be related to its fructan content. The biological activity of fructan can be influenced by the degree of polymerization. Thus, in this study, the inhibitory effects of original and fermented purple Jerusalem artichoke (PJA) on ${\alpha}$-glucosidase were compared in vitro. Additionally, the anti-diabetes effect of Lactobacillus plantarum-fermented PJA (LJA) was studied in a non-insulin-dependent diabetes mellitus animal model (C57BIKsJ db/db). MATERIALS/METHODS: The water extract of PJA was fermented by L. plantarum, and two strains of Bacillus subtilis to compare their anti-${\alpha}$-glucosidase activities in vitro by ${\alpha}$-glucosidase assays. The anti-diabetes effect of LJA was studied in a non-insulin-dependent diabetes mellitus animal model (C57BIKsJ db/db) for seven weeks. During the experiment, food intake, body weight, and fasting blood glucose were measured every week. At the end of the treatment period, several diabetic parameters and the intestinal ${\alpha}$-glucosidase activity were measured. RESULTS: The LJA showed the highest ${\alpha}$-glucosidase inhibitory activity in vitro. In the in vivo study, it resulted in a significantly lower blood glucose concentration than the control. Serum insulin and HDL cholesterol levels were significantly higher and the concentrations of triglycerides, non-esterified fatty acids, and total cholesterol were significant lower in mice treated with LJA after seven weeks. In addition, the intestinal ${\alpha}$-glucosidase activity was partially inhibited. CONCLUSIONS: These results suggested that LJA regulates blood glucose and has potential use as a dietary supplement.

In vitro Inhibitory Activity on Rat Intestinal Mucosa ${\alpha}-glucosidase$ by Rice Hull Extract (왕겨추출물의 쥐소장점막 ${\alpha}-glucosidase$에 대한 in vitro에서의 저해효과)

  • Kim, Hye-Young
    • Korean Journal of Food Science and Technology
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    • v.29 no.3
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    • pp.601-608
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    • 1997
  • In order to search for the way to utilize rice hull as a renewable resource, the inhibition on ${\alpha}-glucosidase$ and the fractionation of rice hull extract was investigated. An ethanol extract of rice hull from Japonica-type rice seeds exhibited 30% inhibitory activity on rat intestinal brush border ${\alpha}-glucosidase$ (1.4 mU/mL) in vitro at the concentration of 0.8 mg/mL using 6 mM p-nitrophenyl ${\alpha}-D-glucopyranoside$ as a substrate $(IC_{50}\;162\;mg/mL)$. Among the fractions obtained by partitioning the ethanol extract successively with solvents, the ethyl acetate fraction at the concentration of 0.8 mg/mL was found to exhibit the most potent inhibitory activity i.e. 65% inhibition of ${\alpha}-glucosidase\;(IC_{50}\;0.14\;mg/mL)$. Silica gel column chromatography of the ethyl acetate fraction exhibited slightly higher (90%) inhibitory activity, and its subsequent fractionation by Sephadex LH-20 column chromatography did not improve inhibitory activity. Considering the inhibitory activity and yield, the ethyl acetate fraction obtained by the solvent-partitioning process would be a candidate for the hypoglycemic food if it has in vivo effectiveness.

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Effect of pH values and inoculation amounts for α-glucosidase inhibitory activity in mulberry leaf fermentation

  • Kwon, O-Chul;Ju, Wan-Taek;Kim, Hyun-Bok;Sung, Gyoo-Byung;Kim, Yong-Soon
    • International Journal of Industrial Entomology
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    • v.34 no.2
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    • pp.38-44
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    • 2017
  • Mulberry leaves containing 1-deoxynojirimycin (DNJ) have been recognized as a potentially important source for prevent or treat hyperglycemia. However, DNJ content of natural mulberry leaf are as low as 0.1%. Thus, the most effective method for increasing ${\alpha}$-glucosidase inhibitory activity with the DNJ high-production is needed. In this study, we investigated the influence of ${\alpha}$-glucosidase inhibitory activity according to different pH values (6-9) and inoculation amounts (0.1-0.5%) when Bacillus subtilis cultured on mulberry leaf powder media. We confirmed that ${\alpha}$-glucosidase inhibitory activity was difference according to culture conditions of different pH values, inoculation amounts, and fermentation times. The results of mulberry leaf fermentation according to pH values and inoculation amounts were shown that the optimal conditions for ${\alpha}$-glucosidase inhibitory activity were defined as pH 7 and 9, inoculation amount 0.4%, and incubation until 2 to 4 days. These results can be provided a basic data for the optimal culture conditions increasing ${\alpha}$-glucosidase inhibitory activity from mulberry leaf fermentation.

Fibrinolytic and α-Glucosidase Inhibitory Activities of Wild Mushroom Methanol Extracts (야생버섯 메탄올추출물의 혈전용해 활성과 α-Glucosidase 저해 활성)

  • Kim, Jun-Ho;Lee, Eun-Jin;Seok, Soon-Ja
    • The Korean Journal of Mycology
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    • v.35 no.2
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    • pp.128-132
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    • 2007
  • The aim of this study was to investigate the physiological functionalities of 60 wild mushroom methanol extracts. We determined their fibrinolytic and ${\alpha}-glucosidase$ inhibitory activities. Among them, 11 mushrooms showed fibrinolytic activity. In particular, Armillaria sp. showed the greatest enzyme activity (4.2 plasmin units/ml) in a fibrin plate assay. The fibrinolytic activities of Amanita virosa. Gymnophilus sp. and Lepista nuda were 2.3, and the activities of Amanita citrina and Cortinarius alboviolaceus were 2.1 and 2.0 plasmin units, respectively. In a ${\alpha}-glucosidase$ inhibitory activity test, Naematoloma fasciculare showed the greatest inhibitory activity at 98.5%. The ${\alpha}-glucosidase$ inhibitory activities of Suillus luteus and Gomphidius maculatus were 66.6% and 61.5%, respectively. This study suggests that both Armillaria sp. and N. fasciculare can be used as candidates for the development of new medicine effective to cardiovascular diseases and biofunctional food.

Isolation and Characterization of α-glucosidase Inhibitors from Euonymus alatus (화살나무(Euonymus alatus)로 부터 α-glucosidase 저해 물질의 분리 및 동정)

  • Kim, Shin-Duk
    • 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.

Hypoglycemic Effect of Fermented Soymilk Extract in STZ-induced Diabetic Mice

  • Yi, Na-Ri;Hwang, Ji-Young;Han, Ji-Sook
    • Preventive Nutrition and Food Science
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    • v.14 no.1
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    • pp.8-13
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    • 2009
  • This study investigated the hypoglycemic effect of fermented soymilk extract (FSE) in STZ-induced diabetic mice. FSE was prepared via fermentation of soymilk with Bacillus subtilis followed by methanol extraction. The hypoglycemic effect was determined by inhibitory activities against ${\alpha}$-glucosidase and ${\alpha}$-amylase as well as the alleviation of postprandial glucose level. The non-fermented soymilk extract (SE) was used as control in this experiment. FSE showed higher (p<0.05) inhibitory activities than SE against ${\alpha}$-glucosidase and ${\alpha}$-amylase. The $IC_{50}$ values of FSE for ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.77 ancd 0.94 mg/mL, respectively, which were comparable or even superior to those of acarbose (0.79 and 0.68 mg/mL, respectively). In addition, a further suppression on the postprandial blood glucose levels were observed in the FSE than SE group for both STZ-induced diabetic mice and normal mice. Furthermore, FSE significantly lowered the incremental area under the curve (AUC) in the diabetic mice and the AUC in normal mice corroborated the hypoglycemic effect of FSE (p<0.05). Results from this study suggest that FSE may help decrease the postprandial blood glucose level via inhibiting ${\alpha}$-glucosidase and ${\alpha}$-amylase and the usefulness of FSE was proven to be better than SE.

Hypoglycemic Effect of Padina arborescens Extract in Streptozotocin-induced Diabetic Mice

  • Park, Mi Hwa;Han, Ji Sook
    • Preventive Nutrition and Food Science
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    • v.17 no.4
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    • pp.239-244
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    • 2012
  • This study investigated the hypoglycemic effect of the Padina arborescens extract in STZ-induced diabetic mice. Freeze-dried Padina arborescens were extracted with 80% methanol and concentrated for use in this study. The hypoglycemic effect was determined by inhibitory activities against ${\alpha}$-glucosidase and ${\alpha}$-amylase as well as the alleviation of postprandial blood glucose level. Padina arborescens extracts showed higher inhibitory activities than acarbose, a positive control against ${\alpha}$-glucosidase and ${\alpha}$-amylase. The $IC_{50}$ values of Padina arborescens extracts against ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.26 and 0.23 mg/mL, respectively, which evidenced as more effective than observed with acarbose. The increase of postprandial blood glucose levels were significantly suppressed in the Padina arborescens extract administered group than the control group in the streptozotocin induced diabetic mice. Furthermore, the area under the curve (AUC) was significantly lowered via Padina arborescens extract administration in diabetic mice (p 0.05). These results indicated that the Padina arborescens extract might be used as an inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase and delay absorption of dietary carbohydrates.