• Journal of Nutrition and Health
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• v.53 no.3
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• pp.244-254
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• 2020

Purpose: Ixeris strigosa (IS) is a perennial plant that commonly grows in meadows. The leaves and roots of IS have been used in medicine as a sedative. This study evaluated the antioxidant and carbohydrate-digestive-enzyme inhibitory effects of IS to determine its potential as an essential antioxidant and glycemic inhibitor for type 2 diabetics. Methods: The antioxidative and α-amylase and α-glucosidase inhibitory activities were examined using the water extracts (ISW), ethanol extracts (ISE), and solvent fractions from IS. The antioxidative activities were measured using in vitro methods by measuring the 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity. Results: Investigations of the total polyphenol, flavonoid content, in vitro antioxidant activity, and α-amylase and α-glucosidase inhibitory activities of the IS extract showed that the ISE had higher total phenolic and flavonoid contents than the ISW, as well as high antioxidant activity. The ethanolic extracts of IS (70%) had an α-amylase inhibitory activity of 78.55%. The ethyl acetate fraction (90.56%) showed higher α-glucosidase inhibitory activity than the positive control, acarbose (83.01%). Conclusion: Among the ISE fractions, the ethyl acetate and butanol fractions showed the best digestive enzyme inhibitory activity. Moreover, the antioxidant activity of the extract and the carbohydrate, α-amylase, and α-glucosidase inhibitory effects showed a stronger correlation with the total phenol and flavonoid contents compared to the ISW. As a result, the antioxidant and digestive enzyme inhibitory activities of high ISE are due to the phenolic compounds, particularly the flavonoid compounds. Therefore, ethyl acetate and butanol fractions of the 70% ethanol extract are excellent anti-diabetic functional materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1701-1708
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• 2014

Phenolic compounds, physiological properties, and digestive enzyme inhibitory effect of 70% ethanol extracts from Aster scaber with different extraction methods (stirrer extraction, SE; reflux extraction, RE; autoclave extraction, AE; low temperature high pressure extraction, LTPE; ultrasonification extraction, USE) were investigated. Total polyphenols and flavonoids contents in LTPE were significantly higher than those of other extracts. The amount of substances related to cynarin (1,3-O-dicaffeoylquinic acid) was highest in USE (34.34 mg/g), followed by LTPE (33.83 mg/g), RE (32.27 mg/g), AE (25.40 mg/g), and SE (18.17 mg/g). Chlorogenic acid (5-O-caffeoylquinic acid) and astragalin (kaempferol-3-O-glucopyranoside) were highest in AE and LTPE, respectively. Xanthine oxidase, angiotensin- I converting enzyme, 3-hydroxy-3-methylglutaryl coenzyme A reductase and acetylcholin esterase inhibitory activities of LTPE and USE at a concentration of 50 mg% (w/v) were somewhat higher than those of other extracts. The ${\alpha}$-amylase, ${\alpha}$-glucosidase, trypsin and lipase activities showed the same tendency as physiological properties (concentration of 500 mg%, w/v). Additionally, there was significantly higher or slightly lower inhibitory activity compared to the control group. These results suggest that extracts from Aster scaber have potential to act as functional materials, and LTPE and USE are superior for the enhancement of biological activity.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.34-39
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• 1996

We examined the effects of crude hemicellulose, alcohol-insoluble hemicellulose, high molecular weight soluble polysaccharide (HMS-P : MW>10 kDa) and low molecular weight souble polysaccharide (LMS-P : MW<10 kDa) fraction isolated from buckwheat (raw, roast and steam) on digestive enzyme activity in vitro. The enzyme activities were measured after the polysaccharides-enzyme mixtures were incubated at $37^{\circ}C$ for 5 min. Crude hemicellulose, alcohol-insoluble hemicellulose and residue lowered ${\alpha}-amylase$ activity, whereas HMS-P and LMS-P had no inhibitory effect. All polysaccharides except LMS-P lowered lipase activity. Crude hemicellulose, alcohol-insoluble hemicellulose, residue and HMS-P showed a marked decrease of trypsin and chymotrypsin activity but LMS-P showed a slight decrease of them.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.652-658
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• 2012

This study was carried out to identify the ACE (Angiotensin converting enzyme) inhibitory activity of casein hydrolysates for development of anti-hypertensive hydrolysates. Sodium caseinate was treated with six kinds of commercial proteases such as Flavourzyme, Protamex, Neutrase 1.5, Alcalase, Protease M, and Protease S for 8 h individually, and was then treated with the enzyme combination for 4 h at $45^{\circ}C$. The hydrolysate which had the highest ACE inhibitory effect was then hydrolysed successively with three digestive enzymes: pepsin, trypsin, and ${\alpha}$-chymotrypsin, at $37^{\circ}C$ for 4 h under conditions mimicking those of the gastrointestinal tract. UF (ultra filtration) treatment was applied to one of the secondary hydrolysates to determine ACE inhibitory activity. When sodium caseinate was hydrolysed by commercial proteases, the degree of hydrolysis (DH) showed 2.54 to 4.25% and after secondary hydrolysis, DH showed 4.30 to 5.22%. ACE inhibitory activity and $IC_{50}$ values decreased, and inhibition rates increased during hydrolysis. Protamex treatment showed the lowest $IC_{50}$ value ($516{\mu}g/mL$) and Flavourzyme hydrolysate showed the highest $IC_{50}$value ($866{\mu}g/mL$). As the first hydrolysate was treated with Flavourzyme, the ACE inhibitory activity increased. Neutrase hydrolysate had the highest activity with an $IC_{50}$ value ($282{\mu}g/mL$). When Neutrase plus Flavourzyme treatment was hydrolyzed by digestive enzymes, the $IC_{50}$ value ($597{\mu}g/mL$) was decreased statistically (p<0.05). As Neutrase plus Flavourzyme hydrolysate is treated by UF with MW cut-off 10,000, permeate showed $273{\mu}g/mL$ of $IC_{50}$ value, showed no difference, but retentate which has over MW 10,000 showed statistically different $IC_{50}$ value, $635{\mu}g/mL$ (p<0.05).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.875-881
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• 1998

To develop functional food material with angiotensin converting enzyme (ACE) inhibitory peptides, muscle protein of anchovy, Engraulis japonica was hydrolyzed during 48 hrs by digestive pretenses such as pepsin, trypsin, $\alpha$-chymotrypsin, and commercial proteases such as papain, bromelain, complex enzyme, Elavourzyme, Novozym, Neutrase, Protamex and Alcalase. The only $50\%$ ethanol soluble hydrolysates were tested for inhibitory activity against ACE and yield of $50\%$ ethanol soluble peptide-nitrogen ($ESPN_{50}$). ACE inhibition effects and yield of $ESPN_{50}$ occurred as hydrolysis time increased to 8 hrs, Among those pretenses tested, hydrolysates by Alcalase and $\alpha$-chymohypsin had greater ACE inhibitory activity (80 and $74\%$, reipectively) with eletated levels of $ESPN_{50}$ (48 and 58 mg/ml, respectively), while Protamex hydrolysates had greater ACE inhibitory activities ($73\%$) with reduced levels of $ESPN_{50}$ (7.2mg/ml) than others. Amino acid compositions of $50\%$ ethanol solubles obtained from those hydrolysates were rich in glutamic acid, aspartic acid, cysteine and leucine.

• Culinary science and hospitality research
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• v.19 no.5
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• pp.136-145
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• 2013

Currently many studies aimed at enhancing efficacy of medicinal food on biological activity using bioconversion technology including fermentation process. In this study, the quality characteristics and antioxidative activity of fermented Crataegi fructus was investigated. The antioxidant activity of fermented Crataegi Fructus was assessed by various radical scavenging assays using DPPH (2,2-Diphenyl-1-picrylhydrazyl), FRAP (Ferric ion reducing antioxidant power), Reducing power and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)). Moisture content of fermented Crataegi Fructus was $39.3{\pm}0.06%$. Contents of crude ash, crude protein, and crude fat were $0.20{\pm}0.01$, $1.77{\pm}0.04$, and $1.40{\pm}0.59%$, respectively. Moreover, the hunter's color values of fermented Crataegi Fructus were 79.24 (lightnees), 1.58 (redness), and 31.25 (yellowness), respectively. Total phenolic contents of fermented Crataegi Fructus were $3,015{\pm}250$ GAE ${\mu}g/g$. The antioxidative activities of fermented Crataegi Fructus significantly increased in a dose dependent manner. In addition, fermented Crataegi Fructus slightly (10.4%) inhibited ${\alpha}$-glucosidase activity; however, there was no inhibitory activity against ${\alpha}$-amylase. In terms of proteolytic activity, fermented Crataegi Fructus showed a strong activity than pancreatin (used as a positive control). These results indicate that fermented Crataegi Fructus can be used as a natural resource for material aiding digestion.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2222-2226
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• 2011

Amylase is a digestive enzyme that catalyses the starch into sugar. It has been reported that the green tea flavonoid (or polyphenols) (-)-epigallocatechin 3-gallate (EGCG) inhibits human salivary ${\alpha}$-amylase (HSA) and induced anti-nutritional effects. In this study, we performed docking study for seven EGCG-like flavonoids and HSA to understand the interaction mechanism of HSA and EGCG and suggest new possible flavonoid inhibitors of HSA. As a result, EGCG and (-)-epicatechin gallate (ECG) bind to HSA with complex hydrogen bonding interactions. These hydrogen bonding interactions are important for inhibitory activity of EGCG against HSA. We suggested that ECG can be a potent inhibitor of HSA. This study will be helpful to understand the mechanism of inhibition of HSA by EGCG and give insights to develop therapeutic strategies against diabetes.

• Biomedical Science Letters
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• v.11 no.4
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• pp.517-523
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• 2005

The purpose of this study was to determine the effect of rat intestinal a-glucosidase inhibitor; methanol $(80\%)$, ethanol $(80\%)$ and water extract of Schizandra chinensis in Korea (KS: Schizandra chinensis in Korea) and China (CS: Schizandra chinensis in China). When the final concentration was 1 mg/ml for each sample (KS and CS), methanol extract of KS ($IC_{50}$ 1.62 mg/ml) showed $46.8\%$, ethanol extract of KS ($IC_{50}$ 1.48 mg/ml) showed $47.4\%$, water extract of KS ($IC_{50}$ 1.72 mg/ml) showed $46.3\%$ and methanol extract of CS ($IC_{50}$ 8.35 mg/ml) showed $13.3\%$, ethanol extract of CS ($IC_{50}$ 8.05 mg/lml) showed $16\%$, water extract of CS ($IC_{50}$ 8.37 mg/ml) showed $11.54\%$ of inhibitor for p-nitrophenyl $\alpha-D-glucopyranoside$ (pNPG) $\alpha-glcosidase$ activity, respectively. And the contents of total phenol, flavonoid of Schizandra chinensis were measured. When the final concentration was 1mg/ml for each sample (KS and CS), total phenol and flavonoid in KS were higher than CS, respectively. The order superoxide dismutase (SOD) activity $IC_{50}$ values of each solvent extracts of KS were: 2.006 mg/ml methanol extract, 2.304 mg/ml ethanol extract and 2.5 mg/ml water extract, which were higher than that of each solvent extracts CS as: 2.881 mg/ml methanol extract, 3.085 mg/ml ethanol extract and 3.190 mg/ml water extract.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.6
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• pp.783-788
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• 2010

The purpose of this study is to investigate the antioxidative activity and digestive enzyme inhibition of grape seed extract (GSE). The GSE was tested for its effect on various antioxidative potentials (scavenging activities of DPPH radical, superoxide anion radical and hydroxyl radical) and inhibitory effect of various digestive enzymes (trypsin, $\alpha$-chymotrypsin, $\alpha$-amylase, $\beta$-glucosidase and lipase). DPPH radical scavenging activity ($SC_{50}$, 50% scavenging concentration) of GSE was 4.76${\pm}$0.27 ppm while those of positive controls (EGCG and vitamin C) were 2.22${\pm}$0.12 ppm and 9.50${\pm}$0.72 ppm, respectively. $SC_{50}$ value of GSE against superoxide anion radical and hydroxyl radical were 3.82${\pm}$0.07 ppm and 803.23${\pm}$27.16 ppm, respectively. In addition, $IC_{50}$ values of GSE against trypsin, $\alpha$-chymotrypsin, $\alpha$-amylase, $\alpha$-glucosidase and lipase were 2.17${\pm}$0.59 ppm, 7.46${\pm}$1.25 ppm, 18.25${\pm}$3.54 ppm, 12.30${\pm}$1.12 ppm, and 653.23${\pm}$79.34 ppm, respectively. These results suggest that GSE may be useful for the prevention or treatment of obesity.

• Journal of Life Science
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• v.30 no.12
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• pp.1054-1062
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• 2020

This study was designed to investigate whether extracts from Oxya chinensis sinuosa Mistshenk (an edible insect considered a grasshopper) could inhibit the activity of carbohydrate digestive enzymes and alleviate postprandial hyperglycemia in diabetic mice. Oxya chinensis sinuosa Mistshenk was extracted with 80% ethanol (OEE) or water (OWE) and then concentrated. The carbohydrate digestive enzyme-inhibiting activity of the resulting extracts was evaluated by examining α-glucosidase and α-amylase. The IC50 values of OEE against α-glucosidase and α-amylase were 0.229 mg/ml and 0.106 mg/ml, respectively. This result indicated that OEE has stronger inhibitory effects than OWE and positive control. The blood glucose levels of the diabetic control mice increased after one meal. However, when OEE (300 mg/kg) was added to starch, this increase in postprandial blood glucose levels was significantly suppressed. The area under the curve also significantly decreased following the administration of OEE, which exhibited no cytotoxicity. These results indicate that OEE is more efficacious than OWE and may be used as a carbohydrate digestive enzyme inhibitor, delay carbohydrate digestion and glucose absorption, and thus alleviate postprandial hyperglycemia caused by dietary carbohydrates.