• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.246-252
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• 2012

After a mixed carbohydrate diet, inhibition of ${\alpha}$-amylase and ${\alpha}$-glucosidase involved in the digestion and absorption of carbohydrates can significantly decrease the postprandial increase of blood glucose level. In the course of screening these useful enzyme inhibitors, we selected five kinds of bean, using an in-vitro enzyme inhibition assay method. To evaluate the effect of germination process on the functionality of the bean, we investigated the inhibitory activities of the water extracts of non-germinated bean and germinated bean against ${\alpha}$-amylase and ${\alpha}$-glucosidase, relevant to postprandial hyperglycemia. We also investigated the oxygen radical absorbance capacity(ORAC), total phenolics content, and postprandial blood glucose lowering effect in rats(Sprague-Dawley rat model). Most germinated beans showed significantly higher ${\alpha}$-glucosidase inhibitory activity, compared with non-germinated beans. Among germinated beans, Glycine max had the highest ${\alpha}$-glucosidase inhibitory activity(53.3%). The water extract of germinated Phaseolus vulgaris L. had the highest ${\alpha}$-amylase inhibitory activity(95.1%), followed by Glycine max(58.7%), and Glycine max L. Merr(54.1%). Furthermore, the five germinated beans also showed high antioxidant activities in ORAC assay. Results suggested that the germination process may improve and enhance the anti-hyperglycemia potential and antioxidant activity of the bean.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.3
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• pp.367-375
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• 1998

The physicochemical properties of the $\alpha$-amylase inhibitors from black bean and naked barley is Korea were investigated. Preincubation time for maximum inhibition was 30min and no activity change was seen after that time. Optimum pH of the $\alpha$-amylase inhibitors from the black bean and naked barley was pH 7.0 and the inhibitory activities were stable in the range of pH 6.0~8.0 in both phosphate and Tris-HCI buffer solutions. Both inhibitors maintained more than 50% of activity after incubation for 17 min at 7$0^{\circ}C$. The inhibitors from the black bean and naked barley maintained more than 50% of activities after treatment for 40 min and 30 min with pepsin, and 30 min and 50 min with trypsin, respectively. Both inhibitors functioned via a noncompetitive mechanism and were active against porcine pancreatic and human salivary $\alpha$-amylases. The activities of both inhibitors were linear for the ionic stength ranging from 0 to 0.9. The addition of 70 mM maltose to the reaction mixture caused a maximum increase in the relative activities of both inhibitors, but it did not affect the dissociation of the EI complex. The activities of both inhibitors were significantly enhanced by adding 1mM of K+ or Mg2+.

• 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.

• Food Science and Preservation
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• v.23 no.5
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• pp.738-745
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• 2016

We evaluated the distribution pattern of tannin in 164 sorghum breeding lines and the inhibition rates of amylase, protease, and lipase in sorghum lines with different tannin concentrations. Tannin was existed in the testa of sorghum grain. The tannin content in whole grain of Nampungchal sorghum was 11.54 mg/g, and that in grain (milling rate 73%) and bran fractions was 4.57 mg/g and 28.71 mg/g, respectively. The inhibition rate of ${\alpha}$-amylase, ${\alpha}$-glucosidase, and ${\beta}$-glucosidase in sorghum lines with tannin was higher than that in sorghum lines without tannin. The inhibition rate of ${\alpha}$-glucosidase was greater than 97% in sorghum lines with tannin. The inhibition rate of protease ranged from 20% to 70% in the sorghum lines, showing no discernable trends in tannin content. Lipase inhibition was either very low or not observed and did not seem to correlate with tannin concentration.

• Preventive Nutrition and Food Science
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• v.21 no.3
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• pp.181-186
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• 2016

This study was designed to investigate the inhibitory effect of Gynura procumbens extract against carbohydrate digesting enzymes and its ability to ameliorate postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. G. procumbens extract showed prominent ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory effects. The half-maximal inhibitory concentration ($IC_{50}$) of G. procumbens extract against ${\alpha}$-glucosidase and ${\alpha}$-amylase was $0.092{\pm}0.018$ and $0.084{\pm}0.027mg/mL$, respectively, suggesting that the ${\alpha}$-amylase inhibition activity of the G. procumbens extract was more effective than that of the positive control, acarbose ($IC_{50}=0.164mg/mL$). The increase in postprandial blood glucose levels was more significantly alleviated in the G. procumbens extract group than in the control group of STZ-induced diabetic mice. Moreover, the area under the curve significantly decreased with G. procumbens extract administration in STZ-induced diabetic mice. These results suggest that G. procumbens extract may help alleviate postprandial hyperglycemia by inhibiting carbohydrate digesting enzymes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.498-503
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• 2015

This study was conducted to evaluate the cytotoxicity and ${\alpha}-Amylase$, ${\alpha}-Glucosidase$, pancreatic lipase inhibition in vitro by different solvent fractions from the roots of Codonopsis lanceolata. The values of $IC_{50}$ against Calu-6 cell showed a high effect in n-hexane fraction ($10.13{\mu}g/mL$) whereas DW fraction exhibited the weakest inhibition on cell viability, having an $IC_{50}$ value of over $1,000{\mu}g/mL$. The values of $IC_{50}$ against HCT-116 cell showed the highest activity in n-BuOH fraction ($102.01{\mu}g/mL$), followed by n-hexane fraction ($145.85{\mu}g/mL$), methylene chloride fraction ($332.02{\mu}g/mL$), ethyl acetate fraction ($462.93{\mu}g/mL$) and DW fracion ($>1,000{\mu}g/mL$). ${\alpha}-Amylase$ inhibitory activity in methylene chloride fraction and ethyl acetate fraction was found to have a higher inhibitory effect with 24.5% and 25.6% than the other fractions. The highest ${\alpha}-Glucosidase$ inhibitory activity was observed from the ethyl acetate fraction extract, while the extract of DW fraction showed the lowest level of inhibitory activity at given experiment concentration. The pancreatic lipase inhibitory activity of C. lanceolata was found to have a higher the effect in ethyl acetate fraction. Inhibition of lipase activity of the ethyl acetate fraction and n-hexane fraction showed a relatively high, while the extract of DW fraction showed the lowest level at given experiment concentration. These results suggested that the roots of C. lanceolata may assist in the potential biological activity on carbohydrate, lipid Inhibitory activity and anticancer activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.681-686
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• 2015

The purpose of this study was to measure total phenolic compounds as a measure of antioxidant activity as well as ${\alpha}$-amylase inhibitory and ${\alpha}$-glucosidase inhibitory activities as a measure of anti-diabetic efficacy in methanol extracts from 23 kinds of medicinal plants. Extracts of three medicinal plant species showing high total polyphenol contents were selected (Euonymus alatus stem, Taxus cuspidata fruit, and Eucommia ulmoides leaf). Extracts of six medicinal plant species showing over 60% DPPH radical scavenging activity were also selected [Eucommia ulmoides barks (80.10%), Lycium chinense roots (64.25%), Euonymus alatus stem (73.59%), Lespedeza cuneata (78.20%), Taxus cuspidata fruits (70.52%), and Tilia taquetii leaf and stem (67.81%)]. Regarding ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory activities acarbose showing approximately 80% inhibitory activity was selected as a control group, and six species (Eucommia ulmoides heartwood, Eucommia ulmoides bark, Euonymus alatus stem, Dioscorea batatas, Coix lachryma-jobi, and Phaseolus radiatus) showed greater than 80% ${\alpha}$-glucosidase inhibitory activity. Extracts of nine medicinal plant. species showing over 80% ${\alpha}$-amylase inhibitory activity (Pueraria thunbergiana root, Eucommia ulmoides bark, Eucommia ulmoides leaf, Lycium chinense fruits, Euonymus alatus leaf and stem, Euonymus alatus stem, Sasa borealis whole, Dioscorea batatas leaf and stem, and Tilia taquetii leaf and stem). Based on these results, medicinal plants showing high antioxidant and antidiabetic activities can be used as fundamental products in developing new medicines, as well as functional foods to prevent adult disease.

• Preventive Nutrition and Food Science
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• v.7 no.1
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• pp.62-66
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• 2002

As inhibitors of carbohydrate-digesting enzymes can prevent hyperglycemia that is known to cause many macrovascular complications, they may prove a useful adjunct to hypocaloric diets in patients with type 2 diabetes and obesity. Inhibitory activities of two hundred and fifteen kinds of medicinal herb extracts against $\alpha$-glucosidase (EC 3.2.1.20) and $\alpha$-amylase (EC 3.2.1.1) have been investigated in vitro. Adenophora triphylla, Aneilema keisak, and Morus bombysis significantly suppressed rat intestinal $\alpha$-glucosidase activity iu vitro. Porcine pancreatic amylase was efficiently inhibited by methanol extracts of Epimedium koreanum, Campsis grandiflora and Salvia plebeia. Methanol extract of Epimedium koreanum among the medicinal herbs tested showed the strongest inhibitory activity against porcine pancreatic $\alpha$-amylase with 0.1 mg/ML of $IC_{50}$/. The herb extract also improved glucose tolerance in ICR mice when loaded with 0.9 g soluble starch per kg body weight. Taken together, Epimedium koreanum merits further evaluation as a therapeutic measure.

• Korean Journal of Pharmacognosy
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• v.42 no.1
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• pp.61-67
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• 2011

In this study, we evaluated the bioactivities of methanol extract and its solvent fractions of Sonchus asper (L.) Hill. The EtOAc fraction of S. asper exhibited more strong antioxidant activity than other extracts as evidenced by the strongest 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity with a $EC_{50}$ value at $33.55\;{\mu}g/mL$ and reducing power, the total polyphenol (180.71 mg GAE/g) and flavonoid contents (145.86 mg QE/g) of S. asper extract were higher than other extracts. The EtOAc fraction of the S. asper also showed 47.38% mushroom tyrosinase inhibition activity, 56.22% ${\alpha}$-glucosidase inhibition and 46.58% ${\alpha}$-amylase inhibition ratio at 1 mg/mL. Both methylene chloride and EtOAc fractions of methanol extract of S. asper effectively reduced of the 86.34% and 62.03% angiotensin I converting enzyme (ACE) activity at 2 mg/mL, respectively. These findings suggest that the EtOAc fraction of the S. asper could be a potential antioxidant in food additive, medicinal, and industry product.

• Applied Biological Chemistry
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• v.28 no.1
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• pp.28-35
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• 1985

Potato tubers treated at $4^{\circ}C$ for 4 weeks were irradiated with a dose of 0.12 kGy from $^{60}Co$ source and stored at $20^{\circ}C,\;70{\sim}90%$ humidity for 5 weeks. Changes of ${\alpha}-amylase$, peroxidase, indole acetic acid oxidase, indole acetic acid synthesizing enzyme activities were determined. In addition, treatment of gibberellin or indole acetic acid to tubers irradiated were carried out to examine reversal of sprout-inhibition of tubers irradiated. Results are as follows; 1. Irradiation by ${\gamma}-ray$ at 0. 12 kGy dose inactivated easily the enzyme activities in vitro. $D_{37}$ values obtained were 0.94, 0.36 kGy for ${\alpha}-amylase$ and peroxidase, respectively 2. Complete inhibition of the toter sprouting was resulted by the irradiation of tubers with a dose of 0.12 kGy. 3. The indole acetic acid oxidase activity increased 2 times immediately after irradiation. Meanwhile, indole acetic acid synthesizing activity decreased about $50{\sim}75%$ for 5-week storage in irradiated potatoes, whereas the activity increased about 3.5 times along with sprouting in non-irradiated tubers. 4. In morphological aspects, deformed buds with necrosis in the meristmatic tissue were developed in irradiated tubers. Treatment of gibberellin or indole acetic acid at the concentration of 100 or 20 ppm to the irradiated tubers reversed the sprout-inhibition partially. Nevertheless, the deformed buds remained without change.