• Korean Journal of Microbiology
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• v.50 no.4
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• pp.381-383
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• 2014

In the course of screening for ${\alpha}$-glucosidase inhibitor produced by microorganism, the active compound was isolated from the culture filtrate of Bacillus sp. SKU31-1 using a series of chromatography procedures. The structure of the active compound was elucidated as 5-amino-1-hydroxymethyl-1, 2, 3, 4-cyclohexanetetrol on the basis of spectroscopic evidence obtained and comparison with data from the literature. The active compound showed potent inhibitory activity against ${\alpha}$-glucosidase with an $IC_{50}$ value of $1.9{\mu}M$ for maltose and 4.9 mM for sucrose. A Lineweaver-Burk plot indicated that its inhibition of ${\alpha}$-glucosidase was competitive, with a $K_i$ value of 0.15 mM.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.140-142
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• 2006

The aim of this study is to investigate in vitro biological properties of Eucommia ulmoides Oliv. bark. Ethyl acetate(EtOAc) fraction from aqueous extract of Eucommia bark showed strong antioxidant activity of $IC_{50}$ 19.2 ${\mu}g/ml$ by 1,1-diphenyl-2-picrylhydrazyl(DPPH) free radical-scavenging assay. The Eucommia bark extract showed $\alpha$-glucosidase inhibitory activity and inhibited growth of human liver cancer cell, suggesting its potential biological value of anticancer.

• 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.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.30-35
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• 2010

The potential biological activities of methanol extract and 5 fractions (hexane, $CH_2Cl_2$, EtOAc, BuOH and water) from roots of Astragalus membranaceus were examined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, hydroxyl radical (${\cdot}OH$) scavenging activity, reducing power assays, lipid peroxidation inhibitory activity, $\alpha$-amylase and $\alpha$-glucosidase inhibition assays. The EtOAc fraction showed high DPPH free radical scavenging activity ($EC_{50}=170.34\;{\mu}g/mL$), hydroxyl radical scavenging activity ($EC_{50}=32.14\;{\mu}g/mL$), lipid peroxidation inhibitory activity ($EC_{50}=52.46\;{\mu}g/mL$) and a concentration dependence, with OD value ranging from 0.234 to 0.345 (0.1 to 0.5 mg/mL), for reducing power. The EtOAc fraction has the highest total phenolic content ($142.13\;Gal\;{\mu}g/mg$) and the $CH_2Cl_2$ fraction has the highest flavonoid content ($71.63\;Que\;{\mu}g/mg$). Meanwhile, hexane and EtOAc showed certain $\alpha$-amylase and $\alpha$-glucosidase inhibition activities. These results suggest that the methanol extract and fractions from Astragalus membranaceus root have significant antioxidant and anti-diabetes activities, which could be used as a potential source of pharmaceutical materials.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.11
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• pp.1573-1579
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• 2010

This research was performed to determine the antioxidant activity, nitrite scavenging activity, and its inhibitory activity on angiotensin converting enzyme (ACE), xanthine oxidase, $\alpha$-glucosidase, and elastase of hot water extract from pine bud (WPB). Antioxidant activity of WPB was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and superoxide dismutase (SOD)-like activity. DPPH radical scavenging activity and SOD-like activity of WPB were remarkably increased in a dose-dependent manner, and were about 71.4 and 85.4% at 2 mg/mL, respectively. The xanthine oxidase and ACE inhibitory activities were about 70.9 and 51.9% at 2 mg/mL of WPB, respectively. Nitrite scavenging activity of WPB was about 59.1, 53.8, and 39.5% on pH 1.2, 3.0, and 6.0 at 2 mg/mL, respectively. The WPB also showed elastase and $\alpha$-glucosidase inhibitory effects. These results revealed that pine bud have strong antioxidant activity and positive effects on the inhibition of xanthine oxidase, ACE, and elastase.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.55-61
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• 2007

The antioxidant activities of water, ethanol, methanol, and chloroform extracts of Ulmus davidiana were evaluated using various antioxidant assays: DPPH (1,1-diphenyl-2-pricrylhydrazyl) free radical scavenging; hydroxyl radical scavenging; lipid peroxidation scavenging; and reducing power assays. All extracts, except the chloroform extract, demonstrated strong antioxidant activity in all assays. The chloroform extract had the highest hydroxyl radical scavenging activity, and its activity was equivalent to $\alpha$-tocopherol at a concentration of 0.5 mg/mL. Additionally, the antidiabetic activity of their extracts was also evaluated using a rat intestinal $\alpha$-glucosidase inhibition assay. Among all extracts investigated, the methanol extract had the highest $\alpha$-glucosidase inhibitory activity, although its activity was less than acarbose at $0.5\;{\mu}g/mL$. This result suggested that U. davidiana extracts may have antidiabetic activity. Total phenolic compounds and flavonoids were also measured. Phenolic compounds such as tannic acid, p-coumatric acid, and kaempferol were detected by high-performance liquid chromatography (HPLC). These results suggest that U. davidiana extracts may be useful as a potential source of antioxidant and antidiabetic materials.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.529-532
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• 1989

A strain of Streptomyces sp. (YS-221-B) extracellularly produced an inhibitory substance for $\alpha$-D-Glucosidase. The substance was purified 96-fold from culture filtrate by dialysis, heat treatment, adsorption on active carbon, Bio-Gel P-10 and Sephadex G-75 column chromatography with yield of 9.2%. The substance was stable in pH range from 7.0 to 11.0 at 37$^{\circ}C$, and a treatment at 10$0^{\circ}C$ for 20 min diminished only 15% of the original activity. The inhibitor was not inactivated by the treatment of $\alpha$-, $\beta$-amylases, glucoamylases, trypsin and chymotrypsin but inactivated by pyoteases from Streptomyces griseus and Tritirachium album.

• Journal of Life Science
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• v.22 no.7
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• pp.920-927
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• 2012

The objective of this research was to develop the functional material of water and 60% ethanol extracts from nine kinds of mulberry fruits (Morus alba L.) that influence the inhibitory activity on angiotensin-converting enzyme, xanthine oxidase, ${\alpha}$-amylase, and ${\alpha}$-glucosidase. The total phenolic contents in the water extracts were over 2 mg/g in two species (Cheongilppong and Kangwon III) and five species (Daeyoupchosaeng, Cheongilppong, Kangwon III, Hihak, and Cataneo) of 60% ethanol extracts. The inhibitory activity against the angiotensin-converting enzyme was determined with them. Baekwoon III was $90.9{\pm}4.5%$ in the water extracts, and Hihak was $81.8{\pm}4.5%$ in the 60% ethanol extracts. The inhibitory activity of Kuksang 20 against xanthin oxidase was about 10% in the water extracts, and Cataneo was $21.4{\pm}2.3%$ in the 60% ethanol extracts. Six of the species (Daeyoupchosaeng, Suwonppong, Cheongilppong, Kangwon III, Hihak, and Kuksang 20) in the water extracts showed inhibitory activities against ${\alpha}$-amylase, as 100%, respectively. The inhibitory activity of ${\alpha}$-glucosidase was determined for these nine species. Four species (Baekwoon III, Daeyoupchosaeng, Cheongilppong, Kangwon III, Hihak, and Kuksang 20) in the water extracts and three species (Daechoukmyeun, Kangwon III, and Kuksang 20) in the 60% ethanol extracts showed inhibition of over 20%. The results revealed strong biological activity in spite of little total phenolic contents. These water and 60% ethanol extracts with high-quality biological activity from various mulberry fruits (Morus alba L.) are expected to represent good candidates for the development of antihypertentive and antidiabetes sources.

• Korean Journal of Medicinal Crop Science
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• v.21 no.3
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• pp.197-203
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• 2013

We studied the total polyphenol content, DPPH radical scavenging activity, hydroxyl radical scavenging activity and ${\alpha}$-glucosidase inhibition of water extracts from 17 medicinal plants. Total polyphenol contents ranged from 10.0 (Coix lachryma-jobi L, CL) ~ 279.7 (Perilla sikokiana, PS)mg/g. The water extract from medicinal plants were evaluated for its free radical scavenging activities and compared with a commercial antioxidant, ascorbic acid. DPPH radical scavenging activity of Pyrus pyrifolia (PP), Chamaecyparis obtusa L. (COL), Chamaecyparis obtusa F. (COF), and PS were higher than positive control. Higher hydroxyl radical scavenging activity were shown in Acanthopanax senticosus (AS) and Cordyceps militaris (CM) than the other plants. The highest anti-${\alpha}$-glucosidase activity was observed in Cornus officinalis (CO) and Paeonia suffruticosa Andrews (PSA) water extracts. PSA showed not only the higher DPPH radical scavenging activity but also the anti-${\alpha}$-glucosidase activity. The results of our study that PP, COL, COF, PS, AS, CM, CO and PSA could be potential candidates for natural antioxidants.