• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.405-409
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• 2008

This study was performed to investigate the physiological activities of Viola mandshurica. Antioxidant activity was evaluated by measuring total phenolic contents, reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-di-2-ethyl-benzthiazoline sulphonate (ABTS) radical scavenging activity while anti-diabetic activity was measured by inhibition activities on ${\alpha}$-amylase and ${\alpha}$-glucosidase. V. mandshurica extracts were prepared by extracting with four different solvents (methanol, ethanol, acetone, and water). The methanol extract showed the highest total phenol content (34.49 mg/g gallic acid equivalents) among the extracts. The water extract showed the highest reducing power (0.454) at the concentration of $1,000{\mu}g$/mL. The acetone extract showed the most potent radical scavenging activity. DPPH and ABTS radical scavenging activity of the acetone extract at the concentration of $1,000{\mu}g$/mL were 21.13% and 43.53%, respectively. The inhibitory activity of acetone extracts against ${\alpha}$-amylase and ${\alpha}$-glucosidase showed more than 100% at the concentration of $1,000{\mu}g$/mL. The results indicate that V. mandshurica might have potential antioxidant and anti-diabetic activities.

• Preventive Nutrition and Food Science
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• v.5 no.3
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• pp.174-176
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• 2000

Seventeen wild vegetables consumed commonly in Korea were tested for inhibitory activities against alpha-glucosidase, followed by Bupleurum longeradiatum and Angelica decursiva. The hexane-soluble fractions of Hosta longipes, Ainsliaea acerifolia, Pedicularis resupinata, Bupleurum longeradiatum, and Angelica decursiva all at the concentration of 5 mg/ml, inhibited enzyme activity by greater than 50%, and the ethylacetate-soluble fractions of Hosta longipes, and Codonopsis lanceolata, and Bupleurum longeradiatum had relatively strong inhibitory activity against the enzyme. These results suggest that some edible plants merit further evaluation for clinical usefulness as anti-diabetic drugs.

• The Korea Journal of Herbology
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• v.32 no.6
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• pp.1-7
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• 2017

Objectives : The heartwood of Sappan Lignum has been used since ancient times as an ingredient in folk medicines against anti-bacterial and anti-anemia purposes. Many bioactive constituents have been derived from this biomass such as chalcones and homoisoflavonoids. In the current investigation, the antioxidant and anti-diabetic properties using DPPH and $ABTS^+$ radicals scavenging, ${\alpha}-glucosidase$, and advanced glycation end products (AGEs) inhibition assays were evaluated by different extraction methods of Sappan Lignum. Methods : In our continuing investigation for bioactive natural ingredients, the antioxidant and ${\alpha}-glucosidase$ inhibitory properties of Sappan Lignum extracts were prepared from different extraction methods and the biological efficacies were investigated in vitro. The antioxidant properties were evaluated employing radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. In addition, the anti-diabetic effects of Sappan Lignum extracts were tested via ${\alpha}-glucosidase$ and AGEs formation inhibitory assay. The total phenolic contents were determined using a spectrophotometric method. Results : All the tested samples showed dose-dependent radical scavenging and ${\alpha}-glucosidase$ inhibitory activities. Among the tested extracts, the 80% methanolic extract of Sappan Lignum was showed the most potent activity with an $IC_{50}$ value of $82.3{\pm}1.7{\mu}g/m{\ell}$ against DPPH radical scavenging assay. While, $ABTS^+$ radical scavenging activity of 80% methanolic extract was higher than those of other extracts. Also, ${\alpha}-glucosidase$ inhibitory and AGEs formation effects of each extacts and total phenolic contents were evaluated. Conclusions : These results suggested that Sappan Lignum can be considered as a new effective source of natural antioxidant and anti-diabetic materials.

• Korean Journal of Medicinal Crop Science
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• v.15 no.2
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• pp.128-131
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• 2007

This study was carried out to investigate inhibitory effect of extracts from Artemisia capillaris Thumb. on maltase, sucrase, ${\alpha}-amylase$, nonspecific ${\alpha}-glucosidase$, and postprandial hyperglycemia. Methanol extract and organic solvent (n-hexane, ethyl acetate, butanol, aqueous) fractions from the medicinal herb were determined for the inhibitory activities against maltase, sucrase and ${\alpha}-amylase$. The methanol extract from A. capillaris strongly inhibited maltase (57%) and ${\alpha}-glucosidase$ (72%) at the concentration of 100 ${\mu}g/m{\ell}$. Among the four fractions (n-hexane, ethyl acetate, butanol, aqueous) examined, the butanol fraction from A. capillaris showed potent inhibitory effects on maltase (73%), sucrase (33%), and ${\alpha}-amylase$ (75%) at the concentration of 100 ${\mu}g/m{\ell}$. The butanol fraction from Artemisia capillaris also exhibited significant reductions (20%) of blood glucose elevation in mice loaded with maltose. These results suggest that the extract from Artemisia capillaris can be used as a new nutraceutical for inhibition on postprandial hyperglycemia

• Journal of Life Science
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• v.27 no.9
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• pp.1052-1058
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• 2017

Gelidium amansii shows antioxidant and anti-obesity effects; however, the effect on postprandial blood glucose levels is not known. The objective of the present study was to investigate the inhibitory effect of Gelidium amansii extract (GAE) on carbohydrate-digesting enzymes and its ability to alleviate postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. Gelidium amansii was extracted with 80% ethanol and concentrated for use in this study. The ${\alpha}-glucosidase$ and ${\alpha}-amylase$ inhibition assays were performed using the colorimetric method. ICR normal and STZ-induced diabetic mice were orally administered GAE (300 mg/kg body weight) or acarbose (100 mg/kg body weight) alone or soluble starch (2 g/kg body weight). Blood samples were taken from the tail vein at 0, 30, 60 and 120 min. Our results indicated that GAE markedly inhibited ${\alpha}-glucosidase$ and ${\alpha}-amylase$ activities with $IC_{50}$ values of $0.099{\pm}0.009mg/ml$ and $0.178{\pm}0.038mg/ml$, respectively, and was a more effective inhibitor than acarbose, the positive control. Further, the postprandial blood glucose levels of STZ-induced diabetic mice in the GAE-administered group were significantly lower than those of control group mice (p<0.05). Moreover, the area under the curves (AUC) significantly decreased with GAE administration in STZ-induced diabetic mice (p<0.05). These results indicate that GAE may be effective in decreasing postprandial blood glucose levels by inhibiting carbohydrate-digesting enzymes such as ${\alpha}-amylase$ and ${\alpha}-glucosidase$. Therefore, GAE could be used as a potential functional food for alleviating postprandial hyperglycemia.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.274-278
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• 2008

Ethanol extracts from the edible mushroom hinmogi (Tremella fuciformis, TF) were used in the investigation of effects on $\alpha$-glucosidase in vitro and on glucose-uptake in 3T3-L1 mature adipocytes. Addition of the extract significantly inhibited $\alpha$-glucosidase from small intestine of porcine and of rat (about 42 and 35% of control, respectively), and stimulated glucose uptake (about 100% of control), of which activity was higher than that of maitake (Grifola frondosa) X-fraction, a well known anti-diabetic substance. When the ethanol extracts were further partitioned successively by organic solvents and purified by silica gel chromatography, the non-polar layer (F-7) from hexane layer showed highest stimulatory activity of glucose-uptake among layers tested. The major components of the F-7 were 1-monooleoylglycerol and 1-monopalmitoylglycerol. Our report is the first description of TF with stimulatory activity of glucose-uptake. These results suggest that TF extracts may constitute a new source of glucose transport activator and could be employed as a potential anti-diabetic material for treatment and preventing diabetes.

• Journal of Microbiology and Biotechnology
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• v.21 no.3
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• pp.263-266
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• 2011

Methylelaiophylin isolated from Streptomyces melanosporofaciens was selected as an ${\alpha}$-glucosidase inhibitor with an $IC_{50}$ value of 10 ${\mu}M$. It showed mixed-type inhibition of ${\alpha}$-glucosidase with a $K_i$ value of 5.94 ${\mu}M$. In addition, methylelaiophylin inhibited the intracellular trafficking of hemagglutinin-neuramidase (HN), a glycoprotein of Newcastle disease virus (NDV), in baby hamster kidney (BHK) cells. Methylelaiophylin inhibited the cell surface expression of NDV-HN glycoprotein without significantly affecting HN glycoprotein synthesis in NDV-infected BHK cells.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1633-1639
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• 2009

Water extracts were extracted on water bath for 3 hrs at 90${^{\circ}C}$ after 5 times water was added to hot-air dried garlic (DG) and red ginseng (RG), respectively. Its extracts were dried on rotary evaporator, and then the mixture samples were prepared from RG extracts added to DG extracts at 5, 10, and 15%. To test biological activities such as DPPH, nitrite scavenging, tyrosinase, $\alpha$-glucosidase, human gastric (AGS), and human colon cancer cell (HT-29) growth, dryness of DG, RG, and mixture samples were diluted 500-10,000 $\mu$g/mL adding deionized water, respectively. DPPH scavenging activities of mixture sample were slightly higher than DG and RG sample alone. Nitrite scavenging activity was the highest in DG, and the other samples were below 45%. Inhibition activity of tyrosinase was below 35.0% in tested all samples. Inhibition activity of $\alpha$-glucosidase was lower in DG or RG alone, while its activity of mixture sample was increased in proportion to concentration of RG extracts. Inhibition of AGS cell growth was more effective in mixture samples than DG and RG alone, while inhibition of HT-29 cell growth was more effective in DG or RG alone than mixture samples.

• Natural Product Sciences
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• v.18 no.1
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• pp.47-51
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• 2012

Among 38 Vietnamese medicinal plant extracts investigated for their ${\alpha}$-glucosidase inhibitory activity, 35 extracts showed $IC_{50}$ values below $250{\mu}g/mL$. The MeOH extracts of the heartwood of Oroxylum indicum, the seeds of Caesalpinia sappan, and the fruits of Xanthium strumarium exhibited strong ${\alpha}$-glucosidase inhibitory activity with $IC_{50}$ values less than $50{\mu}g/mL$. Fractionation of the MeOH extract of the heartwood of O. indicum led to the isolation of oroxylin A (1), oroxyloside (2), hispidulin (3), apigenin (4), ficusal (5), balanophonin (6), 2- (1-hydroxymethylethyl)-4H,9H-naphtho[2,3-b]furan-4,9-dione (7), salicylic acid (8), p-hydroxybenzoic acid (9), protocatechuic acid (10), isovanillin (11), and ${\beta}$-hydroxypropiovanillon (12). Compounds 1 - 3, 5, 6, 8, 10, and 12 showed more potent activities, with $IC_{50}$ values ranging from 2.13 to $133.51{\mu}M$, than a positive control acabose ($IC_{50}$, $241.85{\mu}M$). The kinetic study indicated that oroxyloside (2) displayed mixed-type inhibition with inhibition constant (Ki) was $3.56{\mu}M$.

• 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.