• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.18-28
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• 2018

In this study, the antioxidant activities and cytoprotective effects against oxidative stress of Lonicera japonica Thunb. 50% ethanol extract and ethyl acetate fraction were investigated. Using the 1,1-diphenyl-2-picrylhydrazyl assay, the free radical scavenging activity (FSC50) of L. japonica Thunb. 50% ethanol extract and ethyl acetate fraction was determined as 152.00 and $77.25{\mu}g/ml$, respectively. To measure the reactive oxygen species (ROS) scavenging activity, the total antioxidant capacity (OSC50) was determined by using a luminol-dependent chemiluminescence assay. The antioxidant activity of the ethyl acetate fraction ($0.33{\mu}g/ml$) was approximately four times stronger than that of the 50% ethanol extract ($1.12{\mu}g/ml$). The protective effect against $^1O_2$-induced cellular damage of human erythrocytes (${\tau}_{50}$) was 46.0 min at $10{\mu}g/ml$ of the 50% ethanol extract and 52.3 min at $1{\mu}g/ml$ of the ethyl acetate fraction. We also investigated the cytoprotective effects against oxidative stress induced by $H_2O_2$ and the intracellular ROS scavenging activity in response to UVB irradiation and found that the extract and fraction protected human skin cells from damage and reduced ROS. These results confirmed that L. japonica Thunb. was a valuable plant-derived natural antioxidant with potential for development as an antioxidative functional ingredient.

• The Korean Journal of Mycology
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• v.31 no.2
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• pp.59-66
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• 2003

Laccase produced by Pycnoporus cinnabarinus SCH-3 isolated from Korea was partially purified using ultrafiltration, anion exchange chromatography and affinity chromatography, The laccase was produced as the predominant extracellular phenoloxidase during primary metabolism. Neither lignin peroxidase nor manganese-dependent peroxidase were detected in the culture fluid. In order to examine the effect of inducers in laccase production, 2,5-xylidine was added in the culture of Pycnoporus cinnabarinus SCH-3. Addition of 2,5-xylidine enhanced 25-fold laccase production. Purified laccase was a single polypeptide having a molecular mass of approximately 66 kDa, as determined by SDS-polyacrylamide gel electrophoresis, and carbohydrate content of 9%. $K_{m}\;and\;V_{max}$ values for laccase with ABTS [2,2-azinobis (3-ethylbenzthiazoline 6-sulfonic acid)] as a substrate (Lineweaver-Burk plot) was determined to be $44.4{\mu}M\;and\;56.0{\mu}mole$, respectively. The optimal pH for laccase activity was found to be 3.0. The enzyme was very stable for 1 hour at $60{\circ}C$. Half-life ($t_{1/2}$) of the enzyme was about 10 min at $80{\circ}C$. Spectroscopic analysis of purified enzyme indicated that the enzyme was typical of copper-containing protein. Substrate specificity and inhibitor studies for laccase also indicated to be a typical fungal laccase. The N-terminal amino acid sequence of the P. cinnabarinus SCH-3 laccase showed 94% of homology to the N-terminal sequences of laccases from P. cinnabarinus PB and P. coccineus.

• Korean Journal of Food Science and Technology
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• v.52 no.3
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• pp.226-236
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• 2020

This study was designed to evaluate the biological activities and main constituents of different parts (fruit, leaf, and stem) of aronia (Aronia melanocarpa). The total phenolic and flavonoidcontents, DPPH and ABTS⁺ radical-scavenging activity, reducing power, and ferric reducing/antioxidant power were observed to follow the order of: leaves > stems > fruits, regardless of extraction solvents. The inhibitory activity against lipopolysaccharide-induced NO production in Raw 264.7 cells was significantly higher in the aronialeaf extract-treated group than in the groups treated with stem and fruit extracts. The ultra-performance liquid chromatography (UPLC) analysis was mainly composed of routine. In addition, the highest content level was measured in the case of the catechinmemberepigallocatechin witha higher value than that found in green tea. Theresults of this studyprovide useful information for understanding the chemical constituents and biological activities of aroniafruits and byproducts.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1409-1413
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• 2000

The seeds of Coix lachryma-jobi L. var. ma-yuen(yullmoo) were investigated for the free radical scavenging and mushroom tyrosinase inhibitory activities. Brown yullmoo, which contains bran in the seed, has also been evaluated for comparison. After partitioning of the total methanol extracts of yullmoo and brown yullmoo, each organic layer exhibited mild or potent dose-dependent inhibition(about 20-80%) on 1,1-diphenyl picryl hydrazyl(DPPH) free radical with the concentration of $300\;{\mu}g/ml$ to $800\;{\mu}g/ml$. n-Butanol fraction of yullmoo showed the most potent scavenging effect on DPPH free radical. $IC_{50}$ of n-butanol fraction was $423\;{\mu}g/ml$, about six to seven fold higher concentration than standard BHT at the same inhibition rate. As for the tyrosinase inhibitory activity, all of the fractions including the methanol extract exhibited the similar activities even after partitioning. The chloroform fraction of brown yullmoo was found to show the most potent inhibitory activity with an $IC_{50}$ of $321.5\;{\mu}g/ml$.