• Journal of Microbiology and Biotechnology
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• v.33 no.10
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• pp.1390-1401
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• 2023

In this study, a 12-week feeding experiment was conducted to characterize the effects of exogenous α-amylase on the growth, feed utilization, digestibility, plasma α-amylase activity, feed degradation rate, and fecal particle size of olive flounder (Paralichthys olivaceus). Diet was supplemented with 0 (AA₀; control), 100 (AA₁₀₀), 200 (AA₂₀₀), or 400 (AA₄₀₀) mg/kg of α-amylase, respectively. Fish (273.1 ± 2.3 g) were stocked into 12 tanks (25 fish/1,000-L tank) and 3 tanks were randomly selected for each diet group. As a result, α-amylase was found to have no significant effects (p ≥ 0.05) on the growth, feed utilization parameters, and whole-body proximate compositions. α-Amylase-treated fish exhibited only a significant increase in the apparent digestibility coefficient of carbohydrates compared to the controls. In addition, in vitro analyses revealed that α-amylase dose-dependently increased (p < 0.05) the feed degradation rate, while photographs of the intestinal content after 2, 4, and 8 h of feeding demonstrated an improved degradation rate in the α-amylase-treated groups. Plasma α-amylase content was higher in the AA₂₀₀ and AA₄₀₀ groups, whereas the control group produced significantly larger-sized fecal particles (90% size class) than these two groups. In the intestine, no changes were observed in the expression levels of the immune-related TNF-α, IL-1β, IL-2, immunoglobulin-M, HSP-70, lysozyme, and amylase alpha-2A. However, growth-related genes IGF-1, IGF-2, TGF-β3, and growth hormone genes were upregulated in muscle tissues. Collectively, exogenous α-amylase has positive roles in the modulation of the digestibility coefficient, blood α-amylase concentration, growth-related gene expression, and diet degradation for improved digestion in olive flounder.

• Journal of Life Science
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• v.25 no.8
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• pp.870-879
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• 2015

The objective of this research was to evaluate the inhibitory activities of phenolic compounds isolated from mulberry (Morus alba) leaves of 109 types against α-amylase and α-glucosidase. The inhibitory activity of the water extracts from Morus alba cv. Kuksang against α-amylase and α-glucosidase were determined as 93.8% and 48.7% respectively. The total phenolic content of extracts from Morus alba cv. Kuksang was 9.7±0.2 mg/g soluble in water and 14.3±0.2 mg/g soluble in ethanol. The inhibitory activity of the water extracts from Morus alba cv. Kuksang at 200 μg/ml phenolics concentration against α-amylase and α-glucosidase were determined as 100% and 82.6% respectively. The purification of inhibitory compounds was carried out by Sephadex LH-20 and MCI-gel CHP-20 column chromatography using a gradient elution procedure by nomal phase type (EtOH→distilled water) and reverse phase type (distilled water→MeOH). The quercetin was confirmed to be the chemical structure of the inhibitory compound against α-amylase and α-glucosidase by spectroscopic analysis of FAB-MS, NMR and IR spectrum.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.828-836
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• 2015

Based on its α-amylase activity at pH 5.0 and optimal pH of the crude enzyme, a strain (named B-5) with acid α-amylase production was screened. The B-5 strain was identified as Bacillus amyloliquefaciens through morphological, physiological, and biochemical characteristics analysis, as well as 16S rDNA phylogenetic analysis. Its α-amylase gene of GenBank Accession No. GU318401 was cloned and expressed in Escherichia coli. The purified recombinant α-amylase AMY-Ba showed the optimal pH of 5.0, and was stable at a pH range of 4.0-6.0. When hydrolyzing soluble starch, amylose, and amylopectin, AMY-Ba released glucose and maltose as major end products. The α-amylase AMY-Ba in this work was different from the well-investigated J01542-type α-amylase which also came from B. amyloliquefaciens. AMY-Ba exhibited notable adsorption and hydrolysis ability towards various raw starches. Structure analysis of AMY-Ba suggested the presence of a new starch-binding domain at its C-terminal region.

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.570-583
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• 2021

Pyrococcus furiosus α-amylase can hydrolyze α-1,4 linkages in starch and related carbohydrates under hyperthermophilic condition (~ 100℃), showing great potential in a wide range of industrial applications, while its relatively low productivity from heterologous hosts has limited the industrial applications. Bacillus subtilis, a gram-positive bacterium, has been widely used in industrial production for its non-pathogenic and powerful secretory characteristics. This study was conducted to increase production of P. furiosus α-amylase in B. subtilis through three strategies. Initial experiments showed that co-expression of P. furiosus molecular chaperone peptidyl-prolyl cis-trans isomerase through genomic integration mode, using a CRISPR/Cas9 system, increased soluble amylase production. Therefore, considering that native P. furiosus α-amylase is produced within a hyperthermophilic environment and is highly thermostable, heat treatment of intact culture at 90℃ for 15 min was performed, thereby greatly increasing soluble amylase production. After optimization of the culture conditions (nitrogen source, carbon source, metal ion, temperature and pH), experiments in a 3-L fermenter yielded a soluble activity of 3,806.7 U/ml, which was 3.3- and 28.2-fold those of a control without heat treatment (1,155.1 U/ml) and an empty expression vector control (135.1 U/ml), respectively. This represents the highest P. furiosus α-amylase production reported to date and should promote innovation in the starch liquefaction process and related industrial productions. Meanwhile, heat treatment, which may promote folding of aggregated P. furiosus α-amylase into a soluble, active form through the transfer of kinetic energy, may be of general benefit when producing proteins from thermophilic archaea.

• Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.181-187
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• 2023

The control of intestinal α-amylase and α-glucosidase is an effective therapeutic strategy for prevention of post-prandial hyperglycemia associated with diabetes mellitus. The objective of this study was to evaluate the anti-diabetes activities of Korean edible seaweed against α-amylase and α-glucosidase, two carbolytic enzymes involved in serum glucose regulation. Of the 41 species initially screened, Cladophora wrightiana var. minor, Eisenia bicyclis, Ecklonia cava, Ishige foliacea, and Ishige okamurae exhibited the strongest inhibitory activities from brown seaweeds. Asparagopsis taxiformis showed the strongest inhibitory effects from red seaweeds. The results of this study suggest that the crude brown seaweed extracts (C. wrightiana var. minor, E. bicyclis, E. cava, I. foliacea, and I. okamurae) and crude red seaweed extracts (A. taxiformis) may have beneficial effects suppressing the rise in postprandial hyperglycemia through the inhibition of α-amylase and α-glucosidase.

• The Korean Journal of Food And Nutrition
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• v.33 no.2
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• pp.210-214
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• 2020

In this study, polyphenol and flavonoid contents were measured, and DPPH, OH, H₂O₂ radical scavenging activity, and the α-amylase inhibitory activity were measured to study the antioxidant activity of 70% ethanol extract from Morinda citrifolia L. The polyphenol and flavonoid contents of noni 70% ethanol extract were 29.52 GAE/g and 12.48 CE/g, respectively. Also, the IC₅₀ values of DPPH, hydroxyl radical, and hydrogen peroxide scavenging activity of 70% ethanol extract from noni were 18.70 mg/mL, 26.45 mg/mL, and 35.67 mg/mL, respectively. Measurement of the α-amylase inhibitory activity of 70% ethanol extract from noni showed 45% inhibitory activity at 10 mg/mL.

• Journal of the Korean Wood Science and Technology
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• v.32 no.6
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• pp.36-42
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• 2004

Inhibitors of α-amylase are important for the treatment of diabetes and obesity. Using enzyme inhibitor's activity, ethanolic extracts of 87 species in 12 families were screened and compared their inhibitory effect on α-amylase, As a results, we can find that extracts of Distylium racemosum, Acer tegmentosum, Corylapsis veitchiana, Cornus walteri and Corylapsis spicata showed higher α-amylase inhibitory activities than the others and have potential possibility of using control agents for carbohydrate-dependent disease.

• Mycobiology
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• v.51 no.1
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• pp.60-66
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• 2023

In this study, the α-amylase inhibitory activity, α-glucosidase inhibitory activity, pancreatic lipase inhibitory activity, and Xanthine Oxidase inhibitory activity of the fruiting body extracts of 5 varieties of Agaricus bisporus (AB) were confirmed. First, the α-amylase inhibitory activity of AB12, AB13, AB18, AB34, and AB40 methanol extracts was lower than that of acarbose, a positive control, in all concentration ranges. The α-glucosidase inhibitory activity of the AB40, AB13, and AB12 methanol extracts at the extract concentration of 1.0 mg/mL was 80.5%, 81.3%, and 78.5%, respectively, similar to that of acarbose, a positive control. The pancreatic lipase inhibitory activity of the methanol extract of Agaricus bisporus fruiting body was significantly lower than that of the positive control orlistat in the concentration range of 50~1.000 (mg/mL). The Xanthine Oxidase inhibitory activity was 0.5~8.0 mg/mL of each extract, which was significantly lower than that of the positive control allopurinol in the same concentration range. However, the Xanthine Oxidase inhibitory activity of AB13 and AB40 at 8.0 mg/mL was about 70%, which was higher than that of other mushrooms. In conclusion, five kinds of Agaricus bisporus fruiting bodies seem to have inhibitory effects on enzymes such as α-amylase, α-glucosidase, pancreatic lipase, and Xanthine Oxidase that degrade starch and protein. In particular, it has an inhibitory effect and a reduction effect on xanthine oxidase that causes gout, so it is expected that it can be developed and used as a food or health supplement with health functional properties through future research.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.328-333
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• 2015

A Myagropsis myagroides (Mm) methanol extract showed α-amylase inhibitory activity of 13% at a concentration of 5 mg/ml. Results showed that the hexane fraction from the Mm methanol extract exhibited α-amylase inhibitory activity with an IC₅₀ value of 4.24 mg/ml. The hexane fraction was separated using silica-gel column chromatography, and six subfractions were obtained. The fraction eluted with CHCl₃:MeOH = 50:1 showed the highest α-amylase inhibitory activity with an IC₅₀ value of 0.72 mg/ml. This fraction was purified using Sephadex LH-20 column chromatography and an octadecyl silica (ODS) Sepak cartridge, obtaining seven subfractions. Fraction (Fr.) 4 also showed a strong α-amylase inhibitory activity with an IC₅₀ value of 0.75 mg/ml. Fr. 4 was purified by Sephadex LH-20 column chromatography and ODS Sepak cartridge, obtaining six subfractions. Fr. 4-2 was identified as sargachromanol I with an IC₅₀ value of 0.40 mg/ml, and the inhibition pattern analyzed from Lineweaver-Burk plots revealed it to be an uncompetitive inhibitor. These results suggest that Mm has potential as a natural antidiabetes agent.

• Korean Journal of Pharmacognosy
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• v.47 no.1
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• pp.24-28
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• 2016

This study was to evaluate the effect of ginseng (Panax ginseng) seed oil on the ${\alpha}$-glucosidase and ${\alpha}$-amylase. Each ginseng seed oils (HE, SE, EE) exhibited a significant inhibitory effect (p<0.001) at all concentrations (10 and 20 mg/ml) on ${\alpha}$-glucosidase activity. HE is the highest inhibitory activity (86.92%) at a concentration of 20 mg/ml, SE and EE showed an inhibitory effect of 77.13% and 65.83%, respectively. And also, Each ginseng seed oils (HE, SE, EE) exhibited a significant inhibitory effect (p<0.001) at all concentrations (1 and 2 mg/ml) on ${\alpha}$-amylase activity. HE is the highest inhibitory activity (89.68%) at a concentration of 2 mg/ml, SE and EE showed an inhibitory effect of 76.99% and 65.70%, respectively.