• Preventive Nutrition and Food Science
• /
• v.18 no.3
• /
• pp.163-168
• /
• 2013

In this study, we investigated the inhibitory effects of Baechu kimchi added Ecklonia cava on the activities of ${\alpha}$-glucosidase and ${\alpha}$-amylase and its alleviating effect on the postprandial hyperglycemia in STZ-induced diabetic mice. Baechu kimchi added Ecklonia cava (BKE, 15%) was fermented at $5^{\circ}C$ for 28 days. Optimum ripened BKE was used in this study as it showedthe strongest inhibitory activities on ${\alpha}$-glucosidase and ${\alpha}$-amylaseby fermentation time among the BKEs in our previous study. The BKE was extracted with 80% methanol and the extract solution was concentrated, and then used in this study. The BKE extract showed higher inhibitory activities than Baechu kimchi extract against ${\alpha}$-glucosidase and ${\alpha}$-amylase. The $IC_{50}$ values of the BKE extract against ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.58 and 0.35 mg/mL, respectively; BKE exhibited a lower ${\alpha}$-glucosidase inhibitory activity but a higher ${\alpha}$-amylase inhibitory activity than those of acarbose. The BKE extract alleviated postprandial hyperglycemia caused by starch loading in normal and streptozotocin- induced diabetic mice. Furthermore, the BKE extract significantly lowered the incremental area under the curve in both normal and diabetic mice (P<0.05). These results indicated that the BKE extract may delay carbohydrate digestion and thus glucose absorption.

• BMB Reports
• /
• v.40 no.4
• /
• pp.494-500
• /
• 2007

The endophytic bruchid pest Callosobruchus maculatus causes severe damage to storage cowpea seeds, leading to economical losses. For this reason the use of $\alpha$-amylase inhibitors to interfere with the pest digestion process has been an interesting alternative to control bruchids. With this aim, $\alpha$-amylase inhibitors from baru seeds (Dipteryx alata) were isolated by affinity chromatographic procedures, causing enhanced inhibition of C. maculatus and Anthonomus grandis $\alpha$-amylases. To attempt further purification, this fraction was applied onto a reversed-phase HPLC column, generating four peaks with remarkable inhibition toward C. maculatus $\alpha$-amylases. SDS-PAGE and MALDI-ToF analysis identified major proteins of approximately 5.0, 11.0, 20.0 and 55 kDa that showed $\alpha$-amylase inhibition. Results of in vivo bioassays using artificial seeds containing 1.0% (w/w) of baru crude extract revealed 40% cowpea weevil larvae mortality. These results provide evidence that several $\alpha$-amylase inhibitors classes, with biotechnological potential, can be isolated from a single plant species.

• The Korean Journal of Food And Nutrition
• /
• v.33 no.2
• /
• pp.210-214
• /
• 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 East Asian Society of Dietary Life
• /
• v.25 no.1
• /
• pp.139-145
• /
• 2015

This study evaluated the functional characteristics of saccharified buckwheat (Fagopyrum esculentum) following ${\alpha}$-amylase, ${\beta}$-amylase or glucoamylase treatment based on changes in soluble solid contents, rutin and quercetin contents, total polyphenols and DPPH radical scavenging activity. The results showed that the amylase treatments significantly influenced the saccharification time. Additionally, total polyphenol, rutin, and quercetin contents increased during the saccharification process; increase in phenolic compounds induced antioxidant activity. The present study demonstrated that buckwheat has a higher amount of functional compounds and higher antioxidant activity after saccharification. These results show that buckwheat saccharification can be used to increase antioxidant capacity and functional value for applications in functional food industries.

• Natural Product Sciences
• /
• v.13 no.4
• /
• pp.311-316
• /
• 2007

In this study, the twenty-four ethyl acetate extracts of twenty-two medicinal plants, traditionally used in Vietnam as anti-diabetes agents, were investigated for ${\alpha}$-amylase and protein tyrosine phosphatase 1B (PTP1B) enzymes inhibitory activity in vitro. The results indicated that, twelve materials (50.0%) showed moderate to strong inhibitory activity in ${\alpha}$-amylase inhibitory activity with $IC_{50}$ values ranging from 2.5 to $48.8{\mu}g/mL$; meanwhile, ten extracts (41.6%) could demonstrate PTP1B activity with $IC_{50}$ values less than $30.5{\mu}g/mL$. Some plants presented interesting activities against both of ${\alpha}$-amylase and PTP1B enzymes such as Catharanthus roseus, Carthamus tinctorius, Momordica charantia, Gynostemma pentaphyllum, Glycyrrhiza glabra, Smilax glabra, Psidium guajava (leave), and Rehmannia glutinosa. The study may provide a proof, at least in a part, for the ethno-medical use in diabetes disease of these plants.

• The Korean Journal of Mycology
• /
• v.24 no.1 s.76
• /
• pp.8-16
• /
• 1996

The ${\alpha}-amylase$ of Alternaria alternata was purified through ammonium sulfate precipitation, dialysis and Sephadex G-100 column chromatography. One single band was obtained in SDS-polyacrylamide gel electrophoresis. The optimum pH for enzyme activity was 5.0 and the enzyme activity was maintained at $3.6{\sim}7.0$pH range. The optimum temperature for ${\alpha}-amylase$ activity was $40^{\circ}C$ and 71% of the activity was still maintained until 30 min after heating at $80^{\circ}C$. The ${\alpha}-amylase$ was slightly activated by $Mn^{2+},\;Zn^{2+}\;and\;Sn^{2+}$, but inhibited by $Ba^{2+},\;Pb^{2+},\;Co^{2+}\;and\;Ag^{1+}$. The $Hg^{2+}\;and\;Ag^{2+}$ slightly inhibited the activity of the enzyme at concentrations of $10^{-3}\;and\;10^{-4}M$. The Michaelis constant $(K_m)$ to soluble starch was $6.50{\times}10^{-2}M$ and inhibition constant $(K_i)$ by the 1mM EDTA was $8.0{\times}10^{-2}M$. The inhibition of this enzyme by EDTA was competitive one.

• The Korean Journal of Mycology
• /
• v.17 no.3
• /
• pp.145-148
• /
• 1989

An acid-stable ${\alpha}-amylase$ produced by Aspergillus niger K-25 strain was purified by fractional precipitation with ammonium sulfate, ethacridine and acetone. The final preparation was homogeneous in cellulose acetate electrophoresis. The enzyme retained 91 % of its oringinal activity at pH 3.0, 8.7% at pH 2.4. The optimum pH of the enzyme was around pH 4. The purified-enzyme with optimum temperature of $40^{\circ}C$ was more heat-stable than the commercial product. The enzyme retained 80% of its original activity when heated to $60^{\circ}C$ for 30 minutes while the commercial amylase lost its acitivity completely within 30 minutes at $50^{\circ}C$.

• KSBB Journal
• /
• v.14 no.6
• /
• pp.707-712
• /
• 1999

We have produced new-structured oligosaccharides using mixed-enzyme reactor of dextransucrase from Leuconostoc mesenterides B-512FMCM and ${\alpha}$-amylase. When the concentrations of sucrose and starch were 10%(w/v) and 5%(w/v), respectively, the maximum yield of oligosaccharides with both dextransucrase(100U) and ${\alpha}$-amylase(1000U) was 66.4%. The activity of dextransucrase in mixed-enzyme reactor was increased about 2.5 times by acceptor reaction with starch hydrolyzates. As the activities of dextransucrase:${\alpha}$-amylase were increased from 20U:200U to 500U:5000U, the amount of polymer was increased and the yield of oligosaccharides was decreased. By the addition of sucrose into mixed-enzyme reactor following the prehydrolysis of starch with ${\alpha}$-amylase, the yield was increased up to 12% compared with that of mixed-enzyme reactor without the addition of starch hydrolyzate. New structured-oligosaccharides showed heat resistance up to 140$^{\circ}C$ and was stable in acidic condition at pH 3~6.

• Korean journal of food and cookery science
• /
• v.15 no.5
• /
• pp.533-538
• /
• 1999

${\alpha}$-amylase was investigated as an antistaling agent for Backsulgie, a traditional rice cake. Rice powder was mixed with ${\alpha}$-amylase, fermented for 2 hr at 37$^{\circ}C$, and steamed for 20 min. Rice cake was stored at room temperature or freezer for 4 days, and analyzed to determined the changes of chemical and sensory properties. When ${\alpha}$-amylase was added to rice cake, the content of reducing sugars and the yellow color of the cake were increased, and the water activity was decreased. Soft and moist textural properties were apparent in ${\alpha}$-amylase-added rice cakes by sensory evaluation. X-ray diffraction showed a V pattern after 4 days of storage which indicated the starch of rice cake was not retrograded. However, there was no significant difference in moisture content between enzyme-treated and non-treated rice cakes. Above results suggest that ${\alpha}$-amylase treatment produced dextrins which consequently bound with water and inhibited the retrogradation of rice cake.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.44 no.4
• /
• pp.391-395
• /
• 1999

Barnyardgrass had relatively higher growth vigor at the earlier growth stage than inbred rice did, showing the 2 fold higher $\alpha$-amylase activity during the periods of germination and large leaf area Expansion with high net photosynthetic rate at the earlier autotrophic stage, but it performed weak growth at the late growth stage. However, the hlybrid rice Shanyou 63 had significantly higher $\alpha$-amylase activity and net photosynthetic rate than that of barnyardgrass, exhibiting heterosis for two physiologica1 traits during the germination (6~12 days) and autotrophic phase, respectively. Accordingly, hybrid rice, Shanyou 63, exhibited heterotic effect at the early growing stage when were presented with barnyardgrass. Shanyou 63 exhibited stronger tillering ability, faster leaf area expansion and higher net photosynthetic rate than those of barnyardgrass.