• Applied Biological Chemistry
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• v.48 no.1
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• pp.103-108
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• 2005

${\alpha}-Amylase$ inhibitor is used to control blood glucose level by inhibiting starch digestion in the small intestine and delaying the absorption of glucose. In this study, we investigated the effect of the ethanol extracts from more than 1400 species of plants against ${\alpha}-amylase$ with the aim of developing a new ${\alpha}-amylase$ inhibitor. In the results, Cornus walteri extracts showed the highest inhibition activity. The inhibitory effect of Cornus walteri extract on the carbohydrate hydrolysis enzymes has different sensitivities against ${\alpha}-amylase$ from salivary and pancreatin and against ${\alpha}-glucosidase$ from yeast and porcine small intestine. In the study of inhibition kinetics of ${\alpha}-amylase$ and ${\alpha}-glucosidase$, Cornus walteri extract showed competitive inhibition against salivary and pancreatin while showing the combination of uncompetitive and noncompetitive inhibition against ${\alpha}-glucosidase$. The Cornus walteri extract was stable at acidic and thermal conditions. As for the blood glucose and body weight levels of Cornus walteri extract, we confirmed anti-hyperglycemic and anti-obesity effects. Also, in the investigation of the mRNA lever, Cornus walteri extract upregulated the level of GLUT4 mRNA in the quadriceps muscle.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.223-232
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• 1985

To find microorganisms of producing $\alpha$-amylase inhibitors, actinomycetes were isolated from soil samples that were collected at different locations in Korea and screened for enzyme inhibitory activity. A strain of these microbes had a high inhibitory activity and was identified as one of the genus Streptomyces by morphological, biochemical and physiological studies according to the methods of the International Streptomyces Project (ISP). The medium used consisted of 3 ％ corn starch, 0.2％ yeast extract and 0.8％ peptone (pH 7.0). When this strain was aerobically cultured in the medium on a rotary shaker, the highest inhibitory activity was obtained after four days. This inhibitor had inhibitory activities on various $\alpha$-amylases and glucoamylase, but not on $\beta$-amylase.

• KSBB Journal
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• v.11 no.2
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• pp.125-131
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• 1996

In this study, Bucillus amyloliquefaciens was adopted as bacterial source to investigate the concentration of carbon source by adding inhibitors in the batch culture. By adding acetic acid at $10g/\ell$ of initial glucose concentration, maximum dry cell density was obtained with the highest value of /$\3.9gell$ at $1.0g/\ell$ of initial acetic acid concentration. By adding acetic acid al 10g/$\ell$ of initial glucose concentration, maximum ${\alpha}$-amylase production was obtained with 331.55unit/m1 at $2.0g/\ell$ of initial acetic acid concentration. ${\alpha}$-Amylase production was decreased with the increase of initial acetic acrid concentration. By adding acetic acid to the medium, cell growth and ${\alpha}$-amylase production was higher in glucose than in maltose. By adding lactic acid to the medium, cell growth was decreased.

• YAKHAK HOEJI
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• v.33 no.3
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• pp.175-182
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• 1989

To find ${\alpha}-amylase$ inhibitors produced by microorganisms from soil, a strain which had a strong inhibitory activity against bacterial ${\alpha}-amylase$ was isolated from the soil sample collected in Korea. The morphological and physiological characteristics of this strain on several media and its utilization of carbon sources showed that it was one of Streptomyces species according to the International Streptomyces Project method. The amylase inhibitor of this strain was purified by active carbon adsorption, silicagel column chromatography, SP-Sephadex C-25 column chromatography, adsorption on Amberlite XAD-2. The inhibitor was oligosaccharide which was composed of glucose. The inhibitor had inhibitory activity against other amylase such as salivary ${\alpha}-amylase$, pancreatic ${\alpha}-amylase$, fungal ${\alpha}-amylase$ and gluco-amylase.

• The Korean Journal of Mycology
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• v.13 no.4
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• pp.203-212
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• 1985

Of 450 strains isolated from the soil microbes collected in various locations in Korea, a strain had a strong inhibitory activity against bacterial ${\alpha}-amylase$ and was named strain DMC-72 of the genus Streptomyces. The amylase inhibitory metabolite produced by this strain was purified by means of acetone precipitation, adsorption on Amberlite IRC-50 and SP-Sephadex C-25. The inhibitor was found to be a derivative of oligosaccharides by spectral and chemical data. The inhibitor was stable at the pH range of $1{\sim}13$ and at $100^{\circ}C$ for half an hour, also inhibited other amylases such as salivary ${\alpha}-amylase$, pancreatic ${\alpha}-amylase$, fungal ${\alpha}-amylase$ and glucoamylase. However, it showed no inhibitory activity against ${\alpha}-glucosidase$, ${\beta}-glucosidase$, dextranase, and ${\beta}-amylase$. The kinetic studies of the inhibitor showed that its inhibitory effects on starch hydrolysis by ${\alpha}-amylase$ were noncompetitive.

• YAKHAK HOEJI
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• v.36 no.4
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• pp.390-396
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• 1992

Streptomyces minoensis DMCJ-144 isolated from soil produces the ${\alpha}-amylase$ inhibitor. Optimum culture conditions for ${\alpha}-amylase$ inhibitor production of the strain were determined in this experiment. The optimum composition of the culture medium was studied by supplementing various carbon sources, nitrogen sources, vitamins, and metal salts to the basal medium containing 1% glucose, 0.1% asparagine, 0.005% $MgSO_4{\cdot}7H_2O$, 0.005% $K_2HPO_4$, 0.005% NaCl. Other culture conditions such as the culture temperature, initial pH of the medium, aeration, and culture time were also investigated. When the strain was cultured in a 100 ml flask containing 20 ml of 2% glucose, 0.5% beef extract, 0.0002% riboflavin, 0.0002% thiamine HCI, 0.01% $ZnCl_2$, 0.005% $MgSO_4{\cdot}7H_2O$, 0.005% $CuSO_4{\cdot}5H_2O$, 0.005% NaCl, pH 7.2, 180 rpm at $30^{\circ}C$, the maximum production of the ${\alpha}-amylase$ inhibitor was observed after 5 days of the cultivation.

• KSBB Journal
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• v.11 no.2
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• pp.132-139
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• 1996

The growth of recombinant E. coil and by-product production were investigated. D-cycloserine was added to increase the secretion of ${\alpha}$-amylase from recombinant E.coil. Even though cell growth was increased for optimal d-cycloserine concentration $0.1g/\ell$, extracellular ${\alpha}$-amylase activity remained almost the same as the case without d-cycloserine. It is important to achieve the high cell density for commercial production of methaboliles including ${\alpha}$-amylase. To achieve this goal, culture conditions should be selected carefully and optimized considering cell growth and by-products production. In cultivating retombinant E. coli, lactic acid and acetic acid turned out to be important by-product which affected cell yield and growth rate.

• Microbiology and Biotechnology Letters
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• v.18 no.4
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• pp.338-343
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• 1990

MB4-03, an $\alpha$-amylase inhibitor was isolated from the culture broth of Streptomyces sp. DMCJ-49 and purified through ion-exchange chromatography, adsorption, and gel filtration. The results of various instrumental analyses showed that the inhibitor was one of oligosaccharides that had glucoses as its major component and that its molecular weight was about 2000. And one methyl group which seemed to be related with the inhibitory activity of this compound was identified. From the CMR spectrum, it was elucidated that this compound was composed of $\alpha$ -D-glucopyranoses which were linked together by $\alpha$ (I -, 4) bond configuration. As the inhibitory effect of this compound was reduced after incubation with $\beta$-amylase, the maltose units was seemed to exist at non-reducing terminal side of it.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.1
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• pp.42-47
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• 2008

Prevention of postprandial hyperglycemia is important, as it is implicated in the development of macro- and microvascular complications associated with diabetes. An inhibitor of ${\alpha}$-amylase which acts in the first step of carbohydrate digestion, is expected to be a suppressor of postprandial hyperglycemia. This study investigated the porcine pancreatic ${\alpha}$-amylase inhibitory activity of the extracts from buckwheat (Fagopyrum esculentum) flower, leaf, stem and grain. Flower, leaf, stem and grain of buckwheat were extracted by water and ethanol (40%, 70%, 100%), respectively. Flower and leaf extracts were more effective ${\alpha}$-amylase inhibitors than stem and grain extracts in all tested solutions. Ethanol extracts were more effective than water extracts or powders on the ${\alpha}$-amylase inhibitory activities. At concentrations of $0.5%{\sim}10%$ (w/w, starch basis), the flower extracts of 40%, 70% and 100% ethanol lowered the enzyme activity by about 90% and the results were similar to the values of acarbose. At the same concentrations, the leaf extracts of 100% ethanol lowered the enzyme activity by about 90%. These results suggest that buckwheat flower and leaf ethanol extracts may delay carbohydrate digestion and lower postprandial hyperglycemia.

• YAKHAK HOEJI
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• v.32 no.5
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• pp.304-307
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• 1988

394 strains of soil microorganism were isolated from the Korean soil samples. The isolated strains were shake-cultured in oat-meal medium. The filtrates of the cultures were screened for the production of ${\alpha}-amylase$ inhibitors. Five strains were identified to produce ${\alpha}-amylase$ inhibitors. And these strains were identified as Actinomycetes.