• Journal of Life Science
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• v.33 no.11
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• pp.936-943
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• 2023

This study was conducted to investigate the potential of Stewartia koreana as anti-microbial materials. The branches, stems and leaves of S. koreana were extracted into 70% ethanol and their antibacterial activity against P. aeruginosa was confirmed. The leaf, branch and stems extracts (1 mg/disc) showed the antibacterial activity against P. aeruginosa and leaf extracts showed higher antibacterial activities than those from branch extracts. The MIC against P. aeruginosa was 0.8 mg/ml and showed bacteriostatic action. The inhibitory effects of extract on biofilm formation and gene expression related to biofilm formation of P. aeruginosa was determined by biofilm biomass staining, SEM and qRT-PCR analysis. The biofilm biomass and cell growth of P. aeruginosa in the cultures treated with 0.2~2.0 mg/ml of S. koreana leaf extracts were significantly decreased in a concentration-dependent manner. We observed that the extract had an inhibitory effect on the formation of P. aeruginosa biofilms at concentrations of 0.8 mg/ml by SEM. qRT-PCR analysis showed that the lasI and rh1I gene expression associated to quorum sensing (QS) in the cultures treated with 0.2~2.0 mg/ml of S. koreana leaf extracts were suppressed in a concentration-dependent manner. Based on the above results, it can be concluded that S. koreana leaf extracts can be used as anti-microbial material derived from natural materials, as demonstrated by the antibacterial action and inhibition of biofilm formation of P. aeruginosa by QS inhibition.

• Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.284-293
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• 2010

To reduce anti-nutritional factors in plant protein sources for fish meal replacement in fish feeds, cottonseed and soybean meal (CS) were fermented with Aspergillus oryzae. A feeding trial was conducted to verify the effects of fermented CS (FCS) with phytase supplementation on gossypol detoxification, phosphorus digestibility, antioxidant activity, and growth performance of juvenile olive flounder over 10 weeks. Four diets were formulated to replace 0, 30, or 40% fish meal protein with CS or FCS (designated as CS0, CS30, FCS30P, and FCS40P). Phytase (1,000 FTU/kg) was added to FCS30P and FCS40P. The microbial fermentation significantly increased dietary total polyphenols and consequently led to higher DPPH radical-scavenging activities in fish feed and fish tissue. Dietary and liver gossypol concentrations were dramatically decreased by the fermentation process. Phosphorus digestibility was significantly increased in fish fed the FCS40P diet. However, growth performance decreased in fish fed FCS diets. This study demonstrates that the fermentation process and phytase supplementation can improve the phosphorus availability of plant protein sources in fish. The fermentation of CS by A. oryzae could increase antioxidant activities in feed and fish and effectively degrade toxic gossypol in cottonseed meal.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.338-344
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• 1998

New type of chitosan derivatives, chitosan-g-MAP, were synthesized by graft copolymerization of mono (2-methacryloyl oxyethyl) acid phosphate (MAP) into chitosan, in order to solubilize chitosan in water. Ceric ammonium nitrate was used as an initiator for graft copolymerization. The optimal conditions for graft copolymerization were determined on the basis of reaction temperature, time, and the concentration of initiator and monomer. The reaction conditions for the highest percentage of grafting were as follows: an initiator concentration, 3.5${\times}$10$\^$-3/ M; monomer concentration, 0.19 M; and reaction temperature, 40$^{\circ}C$ The reaction rate reached the maximum value after 4 hrs of reaction. Antifungal activity was tested against Candida albicans, Trichophyton rubrum and Trichophyton violaceum by using chitosan-g-MAP and two other chitosan samples which have degree of deacetylation of 70% (DA-7) and 90% (DA-90). Their antifungal activities were investigated in weak acidic range. Maximum antifungal activity of them was observed at pH 5.75. Chitosan-g-MAP inhibited thoroughly the growth of Candida albicans and Trichophyton violaceum. Howerver, DA-70 and DA-90 showed higher antifungal activities on Trichophyton rubrum than that of chitosan-g-MAP.

• Journal of Life Science
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• v.23 no.5
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• pp.622-628
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• 2013

Diallyl trisulfide (DATS), one of the major organosulfur components of garlic (Allium sativum), has various biological effects such as anti-microbial and anti-cancer activities. However, the molecular mechanisms of growth inhibition related to cell cycle arrest are poorly understood. In this study, we investigated the effects of DATS on cell cycle progression in U937 human leukemia cells. Treatment with DATS in U937 cells resulted in inhibition of cell viability through G2/M arrest and apoptosis. DATS-induced G2/M arrest was associated with up-regulation of cyclin B1 and cyclin-dependent kinase 1 (CDK1). DATS also significantly increased levels of phospho-histone H3, which is a mitosis-specific marker, indicating that DATS induced mitotic arrest but not G2 arrest in U937 cells. DATS treatment also generated the reactive oxygen species (ROS) in U937 cells; however, pretreatment with N-acetyl-l-cysteine (NAC), a ROS scavenger, significantly attenuated DATS-induced mitotic arrest and apoptosis. Taken together, our data indicate that DATS exhibits anti-cancer effects through mitotic arrest and apoptosis in a ROS-dependent manner.

• Food Science and Preservation
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• v.20 no.4
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• pp.510-517
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• 2013

This study was conducted to investigate the antioxidant and antimicrobial activities of the hot-water and methanol extracts of raw and black Doraji to increase its utilization. In order to prepare the black Doraji, it was steamed for 15 days at a temperature of $60^{\circ}C$ and then it was dried at a temperature of $30^{\circ}C$ for 3 hr. The methanol extract from the black Doraji (BM) contained the highest levels of total polyphenols among the extracts, and the total polyphenol content of the extract from a black Doraji was higher than that of the extract from a raw Doraji. The total flavonoid contents of the hot-water extract from a black Doraji (BW) was the highest (7.94 mgQE/g) among the samples. The DPPH and ABTS radical scavenging activities increased according to the increase in the concentrations of the Doraji extracts. The BM has the highest radical scavenging activity among the extracts. Each extract showed a slight difference in the antibacterial activity according to the tested strains. The Black Doraji showed a higher antimicrobial activity compared to the raw Doraji. The hot-water extracts demonstrated higher activities than the methanol extracts, and the BW revealed the strongest activity. In this study, the black Doraji showed more effect of the antioxidant and anti-microbial activities than the raw Doraji. These results will provide fundamental data for improving the sitological value and the black Doraji can be used as a valuable resource for the development of nutraceutical foods.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.452-460
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• 2016

This study was designed to develop a functional pharma-food using Salicornia europaea (SE). Tiny seeds from the mature SE were collected, and their biological activities were evaluated. The extraction yield of the seed in hot water was found to be 29.6% and the hot water extract (HWE) contained 25.7 mg/g total polyphenol (TP) and 11.5 mg/g total flavonoid (TF), which are similar to those contained in leaf and stem of SE. Among the subsequent organic solvent fractions, the ethylacetate (EA) fraction exhibited the highest content of TP (158.3 mg/g), TF (136.2 mg/g), and total sugar (228.3 mg/g). The EA fraction exhibited broad-range antibacterial activities against gram-positive bacteria, and the butanol fraction exhibited growth inhibitory effect against only Staphylococcus epidermidis. An antioxidation activity assay of the HWE and its fractions showed the EA fraction to have the highest radical scavenging activity with $RC_{50}$ values of 57.0, 29.0, and $28.9{\mu}g/ml$ against DPPH anion, ABTS cation, and nitrite, respectively. The $RC_{50}$ values of vitamin C against DPPH anion, ABTS cation, and nitrite were 10.7, 4.0, and $18.0{\mu}g/ml$, respectively, indicating that the EA fraction of SE has potent antioxidant compounds. In an anticoagulation assay, the EA fraction exhibited a 15-fold extended thrombin time at 5 mg/ml and activated partial thromboplastin time at 7 mg/ml, which are comparable to the activities of aspirin. The HWE and its fractions had no hemolysis activities against human RBCs at up to 1 mg/ml. These results suggest that the EA fraction from SE has a great potential as a new antibacterial and anticoagulation agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1380-1387
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• 2014

The purpose of this study was to develop a mouthwash product with solid fermented oriental medicinal herb (OMH). Solid fermentation of magnolia, liquorice, and cnidium by Phellinus linteus mycelium was carried out successfully when 30% water was added to the medium, whereas 10% brown rice powder was required as an extra nutrient for solid fermentation of mint besides water. The amount of total phenol compounds and DPPH radical scavenging activity of OMH increased significantly (P<0.05) upon solid fermentation. Anti-microbial activities of fermented OMH also increased and were approximately 100-fold greater than those of unfermented samples. Oral pathogens such as Staphylococcus epidermis, Streptococcus pyogenes, Candida albicans, or Streptococcus mutans were used for determination of anti-microbial effects of OMH. Formulation of the mouthwash was developed based on the results of the sensory evaluation. Among seven formulas, the best formula chosen by the sensory evaluation was as follows: mouthwash prepared with 0.075% ethanol extract of solid fermented OMH as a main ingredient, 83.64% hot water extract of mint and clove (100:15, v/v) as a mouthwash base component, and other miscellaneous ingredients, including sodium fluoride, menthol, and surfactants. Data from a consumer's preference test with 30 participants, overall acceptance, and willingness to buy the product developed in this study were all significantly higher for the tested mouthwash compared to mouthwash on the market manufactured with OMH but with a different formula. Duration of freshness of the mouthwash after usage as determined by Breath Checker was not significantly different between the two samples, although the duration of our product was slightly longer than that of the commercial product mentioned above.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.871-876
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• 2010

Seven native and four introduced herbs namely $Thymus$ $quinquecostatus$, $Chrysanthemum$ $zawadskii$ var. $latilobum$, $Rosmarinus$ $officinalis$, etc. were selected for analysis of the DPPH radical scavenging and anti-microbial activity of their extracts. These perennial herbs are classified as $Labiatae$ and $Compositae$ except for $Saururus$ $chinensis$ and can be propagated through seedling and cuttage. These edible herbs are used as medicinal as well as ornamental plants. Their extract has electron donating ability which ranges from 69.7 to 78.7% for native herbs and 67.4 to 75.4% for introduced herbs. Native herbs have higher (3.54%) average DPPH radical scavenging than introduced herbs. In native herbs, maximum DPPH radical scavenging activity was observed in $Agastache$ $rugosa$ (78.7%) followed by $Saururus$ $chinensis$ while $Chamaemelum$ $nobile$ showed highest activity among the introduced herbs. Many herbs viz. $Saururus$ $chinensis$, $Chrysanthemum$ $zawadskii$ var. $latilobum$ and $Solidago$ $virga-aurea$ var. $gigantean$ showed excellent anti-microbial activity against gram positive $Enterococcus$ $faecalis$, maximum (80.0%) by $Saururus$ $chinensis$. Other herbs viz. $Solidago$ $virga-aurea$ var. $gigantea$, $Chrysanthemum$ $zawadskii$ var. $latilobum$, $Salvia$Salvia $plebeia$, $Chrysanthemum$ $indicum$, $Rosmarinus$ $officinalis$, $Chamaemelum$ $nobile$ and $Lavandula$ $stoechas$ showed anti-microbial activity against gram negative $Citrobacter$ $freundii$. Especially, the inhibition of colony growth of $Citrobacter$ $freundii$ was highest in the extract of $Chrysanthemum$ $zawadskii$ var. $latilobum$, and $Chamaemelum$ $nobile$.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.396-402
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• 2012

The chemical composition, anti-porcine epidemic diarrhea virus (PEDV) activity and antimicrobial activity of Artemisia dubia essential oil were evaluated in this study. Fifty eight compounds from A. dubia essential oil were identified through analysis by gas chromatography-mass spectrometry (GC-MS). The major constituents of the oil were camphor (17.18 %), germacrene-D (15.70%), trans (${\beta}-$) racaryophyllene (6.79%), ene thujones (6.57%), 1, 8-cineole (5.94%) and camphene (5.08%). The essential oil was evaluated for antiviral activity against PEDV in Vero cells using a cytopathic effect (CPE) reduction method. The oils actively inhibited PEDV replication with a 50% inhibitory concentration ($IC_{50}$) of 43.7 ${\mu}^3/mL$. The 50% cytotoxicity concentration ($CC_{50}$) of the oils was over 100 ${\mu}/mL$ and the derived therapeutic index was >2.3. Similar analysis of the ribavirin revealed that they have a relatively weaker efficacy when compared to the oils. The antimicrobial activity of the essential oil against 5 microorganisms was evaluated by the disc diffusion method. The essential oil exhibited antimicrobial activity against 5 tested microorganisms with a clear zone of 8-22 mm. Among the tested microorganisms, Streptococcus pyogenes was the most sensitive and Candida albicans the least. Therefore, in can be concluded that essential oils of A. dubia may have interesting applications for microbial control or the control of PEDV-derived diseases.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.119-125
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• 2011

The Egr-1 gene is known to be a transcription factor for activating the expression of many tumor-repressing genes. In this study, three strains activating the promoter of the Egr-1 gene were selected, through the use of Egr-1 luciferase reporter assay and western blotting, from amongst approximately 3,800 oligotrophic bacteria isolated from the cultivated soils of various regions within Korea. These strains were identified as Pseudomonas koreensis on the basis of phylogenetic tree analysis of their 16S ribosomal DNA sequences and biochemical characteristics analyses using a variety of commercial kits (API 20NE, ID 32GN, API ZYM kits). In addition, we discovered that these strains produced anti-bacterial activity against Bacillus subtilis, Staphylococcus aureus and Listeria monocytogenes.