• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.7-13
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• 2011

This study was conducted to investigate the antimicrobial activity of Ginkgo biloba L. leaves, seed and outer seedcoat against bacteria. Antimicrobial effects of Ginkgo biloba L. leaves (GBL), seed (GBS) and outer seedcoat (GBO) were examined by paper disc method and optical density method to determine minimum inhibition concentration (MIC), and observed by scanning electron microscope (SEM) to figure out the morphological change on the surface when Ginkgo biloba leaves extract was treated. The extracts of GBL, GBS and GBO were extracted by solvents such as methanol, ethanol, water. The methanol extract of GBL and GBO showed the highest antimicrobial activity against Bacillus cereus, Bacillus subtilis, Klebsiella pneumoniae, Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus, Yersinia enterocolitica except Escherichia coli and thus was further fractionated. The MICs of the chloroform fraction of GBL methanol extract were $125{\mu}g$/mL against B. subtilis, and L. monocytogenes; GBO methanol extract were $62.5{\mu}g$/mL against B. cereus and $125{\mu}g$/mL against B. subtilis, and L. monocytogenes. The microorganisms were treated with chloroform extracts ($2000{\mu}g$/mL) of GBL and GBO methanol extracts. It was observed by scanning electron microscope (SEM). The cells were expanded and a part of cell wall was completely destructed by GBL and GBO. Thus Ginkgo biloba L. leaves and outer seedcoat could be further developed into a natural antimicrobial agent.

• Korean journal of food and cookery science
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• v.21 no.1 s.85
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• pp.53-63
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• 2005

This study was carried out to determine the inhibitory effect of methanol extract from kimchi ingredients against Salmonella typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Esherichia coli which are pathogenic microorganisms and Aspergillus sp. Penicillium sp. Antimicrobial activity of methanol extracts was tested against bacteria by paper disc method. Antifungal activity of methanol extracts was shown by hyphal growth inhibition ratio. The methanol extracts from all materials were effective against E. coli among them. And the antimicrobial activity of the methanol extracts from ginger and onion were lower than the others. The antifungal activity of the methanol extracts from radish, ginger, and garlic were effective against Aspergillus sp. and Penicillium sp. In the result of identifying antimicrobial effect rate, the methanol extracts from red pepper and radish had more than $40\%$ against S. typhimurium and more than $30\%$ against E. coli. Also the methanol extracts from onion had an high inhibitory effect rate of more than $50\%$ against S. typhimurium and that from garlic had more than $60\%$ against S. aureus. The minimum inhibitory concentration(MIC) of red pepper was examined 500 $\mu$g/mL against L. monocytogenes. This value was the lowest among the others.

• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.56-65
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• 2020

This study attempted to review the possibility of Psidium guajava leaf extract as a cosmetics ingredient by measuring antioxidant activity through ABTS radical scavenging activity, cytotoxicity in RAW 264.7 macrophages, ROS generation-inhibiting effects through DCF-DA assay and antimicrobial activity, and the results found the followings: The Psidium guajava leaf extract revealed excellent ABTS radical scavenging activity. In RAW 264.7 macrophages, no cytotoxicity was found. The ROS generation in the cells was reduced in a dose-dependent manner. The antimicrobial activities were observed in the following strains: S. aureus, E. coli, C. albicans and P. acnes. In terms of minimum inhibitory concentration (MIC) on each strain, which ranged from 0.25 to 1 mg/mL, C. albican was the lowest, followed by E. coli, S. aureus and P. acnes. The above results confirmed the effects of Psidium guajava leaf extract: antioxidant activity, inhibition of ROS generation in the cells, antimicrobial effects on skin flora which causes inflammation. Therefore, it appears that the extract would be available as a cosmetics ingredient which is free of toxins and side effects.

• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.32-39
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• 2010

This study was carried out to investigate the usefulness of the natural antimicrobial substances for natural dyeing. Antimicrobial activity of natural substances, extracted by water, ethanol, methanol and ethyl acetate, were shown over 20 mm by Rheum palmatum, Caesalpinia sappan, Prunus mume, Schizandra chinensis, Rhus javanica, and Coptis japonica. Especially, water and methanol extract of C. japonica were shown strong antimicrobial activity against all investigated strains. Minimum inhibition concentration of C. japonica water extract was investigated 110 mg/mL for Staphylococcus aureus ATCC 6538. Investigated natural substances were not only shown strong antimicrobial activity for natural dyeing but also might be used other industries.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.1014-1019
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• 1994

To develope natural food preservatives, ethanol extract was preapred from the leaf mustard (Brassica juncea Coss) and antimicrobial activities were examined against 12 microorganisms which were food borne pathogens and/or food poisioning microorgaism and food-related bacteria and yeasts. The most active animicrobial concentration of the ethanol extract for most Gram positive microorganisms, Gram negative microorganisms, and lactic bacteria and yeasts was found to be 10, 20 and 40 mg/ml, respectively. when tested by a dose-response manner. Growth of Escherichia coli and STaphylococcus aureus were completely inhibited 4 hours after the addition of more than 20mg/ml of ethanole ethanol extract to the logarithic phase. Scanning electron icrographs of E. coli and Staph, aureus treated with ethanol extrract exhibited morphological changes, including the irregularly contracted cell surface of E. coli and expanded ellipsoidal shape of the Staph. aureus.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.1
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• pp.109-119
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• 2012

This study analyzed the antibacterial activity of the ethanol extract of Schizandra chinensis Baillon against food pathogenic microorganisms to determine its capabilities as a natural antimicrobial agent. A paper disc diffusion test, minimum inhibitory concentration (MIC) determination, and time-kill assay showed that the ethanol extract strongly inhibits the growth of Listeria monocytogenes, Bacillus cereus, Escherichia coli O157:H7, and Pseudomonas aeruginosa. Release of cytoplasmic ${\beta}$-galactosidase was detected in E. coli, E. coli O157:H7, S. aureus, and P. aeruginosa treated with the ethanol extract. An increase of outer membrane permeability caused by the ethanol extract was also observed. An outward flow of cell constituents was detected in the Gram negative strains treated with the ethanol extract. These results imply that the inner and outer membranes of cells were partially destroyed and cell constituents were released by the treatment of the S. chinensis Baillon ethanol extract. The results of this study indicate that ethanol extract of S. chinensis Baillon evidences a fairly good antibacterial effect.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.714-720
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• 2012

To evaluate the antibiotic risk of $Enterococcus$ in fermented soy paste, $Enterococcus$ spp. were isolated and identified from 31 $Cheongkukjang$ and 17 $Doenjang$, samples. Exactly 123 $Enterococcus$ spp., 119 from $Cheongkukjang$ and four from $Doenjang$, were ultimately isolated. The most frequently collected $Enterococcus$ isolates in $Cheongkukjang$ were 69 strains of $E.$ $faecium$ and 20 strains of $E.$ $faecalis$. All four $Enterococcus$ spp. from $Deonjang$ were identified as $E.$ $faecium$. All isolates were sensitive to ampicillin, chloramphenicol, penicillin, and tetracyclin $E.$ However, they showed broad spectra from sensitivity to resistance to erythromycin, ripampin, and streptomycin. Vancomycin minimum inhibition concentration (MIC) of $Enterococcus$ spp. from $Cheongkukjang$ ranged from 0.25 to 8 ${\mu}g/mL$. Almost all strains were sensitive to vancomycin, but eight strains showed intermediate resistance to vancomycin. Seventeen strains showing the highest MIC of 8 ${\mu}g/mL$ among all isolates were evenly distributed among $E.$ $faecalis$, $E.$ $faecium$, $E.$ $gallinarum$, and $E.$ $casselifalvus$, in which the strong resistant genes of $van$A and $van$B for vancomycin were not detected. Overall antibiotic resistance of $Enterococcus$ isolates was relatively low and particularly low vancomycin resistance was similar to those of $Enterococcus$ isolates obtained from other foods. Therefore, the antibiotics resistance of $Enterococcus$ and especially vancomycin-resistant $Enterococcus$ spp. from $Cheongkukjang$ and $Doenjang$, is not hazardous.

• Mycobiology
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• v.45 no.4
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• pp.297-311
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• 2017

Saprolegniasis is one of the most devastating oomycete diseases in freshwater fish which is caused by species in the genus Saprolegnia including Saprolegnia parasitica. In this study, we isolated the strain of S. parasitica from diseased rainbow trout in Korea. Morphological and molecular based identification confirmed that isolated oomycete belongs to the member of S. parasitica, supported by its typical features including cotton-like mycelium, zoospores and phylogenetic analysis with internal transcribed spacer region. Pathogenicity of isolated S. parasitica was developed in embryo, juvenile, and adult zebrafish as a disease model. Host-pathogen interaction in adult zebrafish was investigated at transcriptional level. Upon infection with S. parasitica, pathogen/antigen recognition and signaling (TLR2, TLR4b, TLR5b, NOD1, and major histocompatibility complex class I), pro/anti-inflammatory cytokines (interleukin $[IL]-1{\beta}$, tumor necrosis factor ${\alpha}$, IL-6, IL-8, interferon ${\gamma}$, IL-12, and IL-10), matrix metalloproteinase (MMP9 and MMP13), cell surface molecules ($CD8^+$ and $CD4^+$) and antioxidant enzymes (superoxide dismutase, catalase) related genes were differentially modulated at 3- and 12-hr post infection. As an anti-Saprolegnia agent, plant based lawsone was applied to investigate on the susceptibility of S. parasitica showing the minimum inhibitory concentration and percentage inhibition of radial growth as $200{\mu}g/mL$ and 31.8%, respectively. Moreover, natural lawsone changed the membrane permeability of S. parasitica mycelium and caused irreversible damage and disintegration to the cellular membranes of S. parasitica. Transcriptional responses of the genes of S. parasitica mycelium exposed to lawsone were altered, indicating that lawsone could be a potential anti-S. parasitica agent for controlling S. parasitica infection.

• Research in Plant Disease
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• v.18 no.2
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• pp.109-116
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• 2012

A bacterial strain antagonistic to some fungal phytopathogens was isolated from the stem of a Persimmon tree in Yeongam, Korea. This bacterium was identified as Bacillus subtilis by 16S rRNA gene sequencing and designated as B. subtilis GDYA-1. In in vivo experiment, the fermentation broth exhibited antifungal activities against Magnaporthe oryzae on rice plants, Phytophthora infestans on tomato plants, and Puccinia recondita on wheat plants. We isolated one antifungal compound and its chemical structure was determined by mass and $^1H$-NMR spectral data. The antifungal substance was identified as benzoic acid. It inhibited mycelial growth of M. oryzae, Rhizoctonia solani, Sclerotinia sclerotiorum, and P. capsici with minimum inhibition concentration (MIC) values, ranging from 62.5 to 125 ${\mu}g/ml$. Moreover, the substance effectively suppressed Phytophthora blight of red pepper caused by P. capsici in a pot experiment. To the author's knowledge, this is the first report on the antifungal activity of benzoic acid against phytopathogenic fungi. Benzoic acid and B. subtilis GDYA-1 may contribute to environmental-friendly protect crops from phytopathogenic fungi.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.163-169
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• 2017

The purpose of this study was to estimate the antimicrobial activity of Maesil (Japanese apricot, Prunus mume) extract against Vibrio vulnificus. The strains tested in the study were 28 V. vulnificus isolates originated from fish, seawater, mud flat and seawater in fish restaurant. The vvhA gene was detected using real-time PCR and biochemical identification expressed above good identification in 28 isolates of V. vulnificus. All of V. vulnificus used in this study was susceptible to tetracycline and chloramphenicol antibiotics. These two antibiotics were considered to be useful for the treatment of patients. Maesil extracts 2.5% and 5% showed antimicrobial activity against V. cholerae NCCP 13589 and V. parahemolyticus NCCP 11143. V. vulnificus isolate and V. vulnificus NCCP 11135 showed growth inhibition at 1.25%, 2.5% and 5% of Maesil extract, respectively. Compared with V. cholerae and V. parahemolyticus, the antibacterial activity of Maesil extract against V. vulnificus was high. The minimum bactericidal concentration of Maesil extract for V. vulnificus was 1.6%. These results revealed that Maesil extract was found to be very useful for inhibiting the growth of V. vulnificus and can be expected to prevent food poisoning caused by V. vulnificus.