• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.174-177
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• 2015

A potent α-glucosidase inhibitor (compound I) was isolated from coffee brews by activity-based fractionation and identified as a β-carboline alkaloid norharman (9H-pyrido[3.4-b]indole) on the basis of mass spectroscopy and nuclear magnetic resonance spectra (¹H NMR, ¹³C NMR, and COSY). The norharman showed potent inhibition against α-glucosidase enzyme in a concentration-dependent manner, with an IC₅₀ value of 0.27 mM for maltase and 0.41 mM for sucrase. A Lineweaver-Burk plot revealed that norharman inhibited α-glucosidase enzyme uncompetitively, with a K_i value of 0.13 mM.

• Archives of Pharmacal Research
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• v.20 no.4
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• pp.346-350
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• 1997

The synthesis of cis- and trans-1,6-dihydroxypyrrolizidine starting from trans-4-hydroxy-L-proline and their evaluation as glycosidase inhibitors are reported. The cis-isomer was found to be a potent inhibitor against .alpha.-glucosidase and showed weak inhibitory effect against other glycosidases. The trans-isomer exhibited weak inhibitions of b-glucosidase and amylo-glucosidase and poor inhibition of other glycosidases.

• KSBB Journal
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• v.28 no.6
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• pp.349-355
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• 2013

SC092 strain, producing a polysaccharide degrading enzyme, was isolated from the seawater. This strain was identified as Microbulbifer sp. using the comparative sequence analysis against known 16S rRNA sequence. A polysaccharide degrading enzyme from this strain was used to acquire the enzymatic extracts of Sargassum fulvellum. DPPH radical scavenging and SOD activity of the enzyme extracts of S. fulvellum were about 61.9% and 82.9% at 2 mg/mL, respectively. Nitrite scavenging activities was 52.5% at 2 mg/mL on pH 1.2. In addition, ${\alpha}$-glucosidase inhibitory activity was also increased in a dose-dependent manner and was about 52.7% at 2 mg/mL. To determine the influence of enzyme extracts of S. fulvellum on alcohol metabolism, the generating activity of reduced-nicotinamide adenine dinucleotide (NADH) by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) were measured. ADH and ALDH activities were 118.0% and 177% at 2 mg/mL, respectively. ${\alpha}$-glucosidase inhibitory activity of enzyme extracts of S. fulvellum was remarkably increased in a dose-dependent manner and was about 52.7% at 2 mg/mL. These results indicate alcoholizing and ${\alpha}$-glucosidase inhibitory activities can be enhanced by the enzymatic extracts of S. fulvellum.

• Korean Journal of Microbiology
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• v.31 no.1
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• pp.93-98
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• 1993

To investigate the organic matter transformation in aquatic environment, seasonal fluctuations of heterotrophic activity and microbia] extracellular enzyme activity were studied in Paldang Lake, Korea. The turnover time in the water column and the sediment at the station I fluctuated between 3 -I ,300 hrs and 17-170 hrs for glucose, 5 -1.900 hrs and 15-240 hrs for protein hydrolysate and 4-350 hrs and 15-230 hrs for acetic acid, respectively, indicating that the seasonal turnover time of organic substrates fluctuated drastically. The respiration ratios of glucose. protein hydrolysate and acetate were 23-32%, 38-41% and 22-28% in the water column and 34%, 61% and 41% in the sediment. respectively. These results showed that the respiration ratios in the sediment were higher than those in the water column regardless of kinds of organic substrates. The bacterial extracellular enzyme activities of $\alpha$-glucosidase. $\beta$-glucosidase, N-acetyl-$\beta$-D-glucosaminidase and aminopeptidase were 32-44%. 31-32%, 18-34% and 61-67% in the water column, and 34%. 40%, 23% and 65% in the sediment. respectively.

• 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.

• Nutrition Research and Practice
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• v.1 no.3
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• pp.184-188
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• 2007

The major goal in the treatment of diabetes mellitus is to achieve near-normal glycemic control. To optimize both fasting blood glucose and postprandial glucose levels is important in keeping blood glucose levels as close to normal as possible. ${\alpha}-Glucosidase$ is the enzyme that digests dietary carbohydrate, and inhibition of this enzyme could suppress postprandial hyperglycemia. The purpose of this study was to test the inhibitory activity of methanol extract of Euonymus alatus on ${\alpha}-glucosidase$ in vitro and in vivo to evaluate its possible use as an anti-diabetic agent. Yeast ${\alpha}-glucosidase$ inhibitory activities of methanol extract of E. alatus were measured at concentrations of 0.50, 0.25, 0.10, and 0.05 mg/ml. The ability of E. alatus to lower postprandial glucose was studied in streptozotocin-induced diabetic rats. A starch solution (1 g/kg) with and without E. alatus extract (500 mg/kg) was administered to diabetic rats by gastric intubation after an overnight fast. Plasma glucose levels were measured at 30, 60, 90, 120, 180, and 240 min. Plasma glucose levels were expressed in increments from baseline, and incremental areas under the response curve were calculated. Extract of E. alatus, which had an $IC_{50}$ value of 0.272 mg/ml, inhibited yeast ${\alpha}-glucosidase$ activity in a concentration-dependent manner. A single oral dose of E. alatus extract significantly inhibited increases in blood glucose levels at 60 and 90 min (p<0.05) and significantly decreased incremental response areas under the glycemic response curve (p<0.05). These results suggest that E. alatus has an antihyperglycemic effect by inhibiting ${\alpha}-glucosidase$ activity in this animal model of diabetes mellitus.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.441-444
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• 2002

This study was targeted to develope a microbial consortium having high cellulase production. A filamentous fungus, strain FB01, isolated from a compost showed high ${\beta}-glucosidase$ activity especially. The strain FBOl was co-cultured with Trichoderma viride to enhance the productivity of ${\beta}-glucosidase$, changing inoculation time of one strain (FB01). The microbial consortium prepared showed the higher cellulytic enzyme production than T. viride well-known. The maximal enzyme production was obtained when the microbial consortium was cultured at $30^{\circ}C$ and pH 6.0 for 10days and the activities of CMCase, ${\beta}-glucosidase$, and avicelase were 2.0, 0.8, and 0.2 U/mL, respectively. These enzyme activities were 2, 4, and 2 times as high as those of CMCase, ${\beta}-glucosidase$, avicelase from T. viride, respectively, indicating that a synergistic interaction appeared between T viride and strain FB01. The serial subcultures by pH control increased ${\beta}-glucosidase$ production about 3.2 times. Also, enzyme production using rice-straw as a carbon source showed that the activities of CMCase, ${\beta}-glucosidase$, and avicelase were 3.69, 0.76, 0.17 U/mL, respectively, and ${\beta}-glucosidase$ activity was 1.5 times higher than that of T. viride. Consequently, microbial consortium showed the considerabely enhanced production of the cellullolytic enzymes, such as CMCase, ${\beta}-glucosidase$, and avicelase compared those of T. viride, and a favorable stability for the enzyme production even in the serial subcultures.

• Food Science and Preservation
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• v.24 no.6
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• pp.879-884
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• 2017

In a continuing screening of selected medicinal plants native to Mongolia, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of methanol extract of Iris bungei were investigated. After extraction with 80% of methanol, the methanol fraction was further extracted with n-hexane, EtOAc and n-BuOH in order to obtain four different solvent-soluble fractions, namely n-hexane-soluble, EtOAc-soluble, n-BuOH-soluble and $H_2O$ residue. The antioxidant properties were evaluated by radical scavenging assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. The anti-diabetic efficacy of I. bungei extract was investigated by ${\alpha}$-glucosidase assay. All tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory activities. Among the tested extracts, the EtOAc-soluble fractions showed the greatest radical scavenging activity and ${\alpha}$-glucosidase inhibitory properties among other solvent-soluble fractions. This result suggested that there was a significant relationship between the total phenolic content and biological efficacy. Thus, I. bungei extract might be considered as a new potential source of natural antioxidant and as a ${\alpha}$-glucosidase inhibitory source. A more systematic investigation of this biomass sill be performed for further investigation of activity against antioxidative and anti-diabetic effects.

• Preventive Nutrition and Food Science
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• v.19 no.1
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• pp.5-9
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• 2014

This study was designed to investigate the inhibitory effects of Polyopes lancifolia extract (PLE) on ${\alpha}$-glucosidase activity, ${\alpha}$-amylase activitiy, and postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. The results of this study revealed a marked inhibitory effect of PLE on ${\alpha}$-glucosidase and ${\alpha}$-amylase activities. The $IC_{50}s$ of PLE against ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.20 mg/mL and 0.35 mg/mL, respectively. PLE was a more effective inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase activities than acarbose, the positive control. The postprandial blood glucose levels of STZ-induced diabetic mice were significantly lower in the PLE treated group than in the control group. Moreover, PLE administration was associated with a decreased area under the curve for the glucose response in diabetic mice. These results indicate that PLE may be a potent inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase activities and may suppress postprandial hyperglycemia.

• Korean Journal of Microbiology
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• v.23 no.2
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• pp.77-83
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• 1985

The aim of this investigation was to resolve the contradiction between the results of Sternberg and Mandels (1980, 1982)and those of Nisizawa et al., (1971) in cellulase induction by sophorose, and furthermore to study the conditional effects in sophorose-induced cellulase induction in Trichoderma reesei QM 9414. Sophorose could induce the synthesis of CMCase and ${\beta}-glucosidase$ simultaneously. Optimal induction medium by sophorose had the potassium citrate buffer solution of pH 3.0-4.0 for CMCase, but one of pH 5.0-6.0 for ${\beta}-glucosidase$. At this time, two different types of ${\beta}-glucosidase$ could be induced by sophorose: one was extracellular and had maximum at pH 5.0, the other was intracellular and had maximum activity at pH6.5. Induction study showed that $methyl-{\beta}-glucoside$ was not a true inducer of ${\beta}-glucosidase$ and that large ${\beta}-glucosidase$ induction could be obtained only by the addition of sophorose into the induction medium. Glucose repressed the induction of cellulase by sophorose. The repression of glucose could not be overcome by the addition of cyclic AMP into the induction medium.