• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.439-446
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• 2021

Quercus infectoria (nutgall) has been reported to possess antimicrobial activities against a wide range of pathogens. Nevertheless, the biofilm removal effect of nutgall extract has not been widely investigated. In this study, we therefore evaluated the effect of nutgall extract in combination with cetrimonium bromide (CTAB) against preformed biofilm of Salmonella Typhimurium on polypropylene (PP) and stainless steel (SS) coupons in comparison with other sanitizers. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of nutgall extract and surfactants (CTAB and sodium dodecyl sulfate; SDS) were assessed. CTAB showed a more efficient antimicrobial activity than SDS and was selected to use in combination with nutgall extract for removing biofilm. To determine the biofilm removal efficacy, the PP and SS coupons were individually submerged in 2x MBC of nutgall extract (256 mg/ml) + 2x MBC of CTAB (2.5 mg/ml), nutgall extract alone (256 mg/ml), CTAB alone (2.5 mg/ml), distilled water, and 100 ppm sodium hypochlorite for 5, 15, and 30 min. The remaining sessile cells in biofilm were determined. Overall, the greatest biofilm removal efficacy was observed with nutgall extract + CTAB; the biofilm removal efficacy of sanitizers tended to increase with the exposure time. The SEM analysis demonstrated that S. Typhimurium biofilm on PP and SS coupons after exposure to nutgall extract + CTAB for 30 min displayed morphological alterations with wrinkles. This study suggests nutgall extract + CTAB may be an alternative to commonly used sanitizers to remove biofilm from food contact surfaces in the food industry and household.

• Journal of Microbiology and Biotechnology
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• v.32 no.4
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• pp.504-513
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• 2022

Chitin deacetylase (CDA) inhibitors were developed as novel antifungal agents because CDA participates in critical fungal physiological and metabolic processes and increases virulence in soil-borne fungal pathogens. However, few CDA inhibitors have been reported. In this study, 150 candidate CDA inhibitors were selected from the commercial Chemdiv compound library through structure-based virtual screening. The top-ranked 25 compounds were further evaluated for biological activity. The compound J075-4187 had an IC50 of 4.24 ± 0.16 µM for AnCDA. Molecular docking calculations predicted that compound J075-4187 binds to the amino acid residues, including active sites (H101, D48). Furthermore, compound J075-4187 inhibited food spoilage fungi and plant pathogenic fungi, with minimum inhibitory concentration (MIC) at 260 ㎍/ml and minimum fungicidal concentration (MFC) at 520 ㎍/ml. Therefore, compound J075-4187 is a good candidate for use in developing antifungal agents for fungi control.

• Food Science and Preservation
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• v.11 no.3
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• pp.400-404
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• 2004

This study was conducted to find the antimicrobial activity of garlic extracts by various processing methods(boiled, pan fried, microwave heated, pickled). Ethanol and water extracts from garlic sample were prepared and antimicrobial activities were determined against 10 microoganisms ; food borne pathogens, food poisoning microoganisms, food-related bacteria and yeasts. The ethanol extracts from the fresh and pickled garlic showed antimicrobial activities for test microoganisms, except lactic acid bacteria and yeast. However, the antimicrobial activities were decreased by heat treatment. The minimum inhibitory concentration(MIC) of the fresh garlic extracts was determined to 0.1 mg/mL against an gram positive bacterium and 0.5 mg/mL against an gram negative bacterium. The antimicrobial activities of the ethanol extracts were affected by heating methods and not by pHs.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.3
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• pp.256-262
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• 2017

Essential oil from herb is known to exert pharmacological effects on the human body. In this study we investigated the antibacterial activity of 4 essential oils (teetree, rosemary, melisa, and lavender), as well as the blended mixture oil of teetree, rosemary, and melisa (TRM) on three bacteria, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Antibacterial analysis was performed using the standard disk diffusion method, and minimum inhibition concentration was determined by the broth microdilution method with different concentrations of essential oils (0.5, 1, 2 and 3 mg/mL). After incubation at $37^{\circ}C$ for 24 h, the antibacterial activity was assessed by measuring the zone of growth inhibition surrounding the disks. Herb oil with the inhibition zones showed varied values ranging from6 to 25 mm. However, the components of herb oil of TRM are as highly active as the teetree oil against pathogens, generating large inhibition zones for both gram negative and positive bacteria (13~22 mm and 8 mm inhibition zones). In the analysis for MIC, TRM showed growth-inhibitory effects at 0.0625% for S. aureus and E. coli, and 1.25% for P. aeruginosa. This result demonstrated that the anti-microbial activity of TRM was greater than a single herb oil, including oxacillin, rosemary, and teetrea. As a single herb oil, both rosemary and teetrea also had an anti-microbial effect by itself, and we can expect that the blended oil mixture may exert a synergistic effect against multidrug resistant bacteria, suggesting its future application in natural preservative agents for health food and cosmetics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1098-1105
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• 2004

In order to develop natural food preservatives, the ethanol and water extracts of the Saururus chinensis Baill were prepared. Antimicrobial activity was examined against 10 kinds of harmful microorganisms. The ethanol and water extracts showed the most active antimicrobial activity against B. subtilis and E. coli. The ethanol extract showed stronger antimicrobial activity than that of the water extract. However, the extracts did not show any antimicrobial activity against lactic acid bacteria and yeast. The minimum inhibitory concentrations (MIC) of ethanol extracts against B. subtilis and E. coli were 5 to 10 mg/mL, respectively. Antimicrobial activity of the ethanol extract was not destroyed at 40-12$0^{\circ}C$ and pH 3∼11. The ethanol extract was fractionated in the order of hexane, diethyl ether, ethyl acetate, and water fractions. The highest antimicrobial activity was found in the diethyl ether fraction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.692-696
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• 2001

To develop natural food preservatives, ethanol and water extracts were prepared from the coriander (Coriandrum sativum L.) and antimicrobial activities were examined against 10 microorganisms which were food borne pathogens and/or food poisoning microorganisms and food-related bacteria and yeasts. Ethanol extract exhibited antimicrobial activities for the microorganisms tested, but not on lactic acid bacteria and yeast. Especially, minimum inhibitory concentrations (MIC) for Bacillus subtilis and Bacillus cereus were as low as 0.25mg/mL. antimicrobial activity of the ethanol extract was not destroyed by the heating at 121$^{\circ}C$ for 15min and not affected by pH. The ethanol extract of coriander exhibiting high antimicrobial activities was fractionated in the order of hexane, chloroform, ethylacetate and butanol fractions to test antimicrobial activity. The highest antimicrobial activity adjust bacteria tested was found in the ethylacetate fraction.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.611-618
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• 2001

The ethanol extract of Dryopteris crassirhizoma Nakai showed strong growth inhibition against 5 strains of Listeria monocytogenes at the concentrations of $100{\sim}500$ ppm and the minimum inhibitory concentration of n-hexane fraction was under 50 ppm. The D8-2-5 fraction isolated from n-hexane fraction of Dryopteris crassirhizoma Nakai showed a strong bactericidal activity on 5 strains of L. monocytogenes at 20 ppm level in tryptic soy broth medium. At the level, the viable count was reduced $4{\sim}6$ log cycle compared to initial cell number. Observation by the measurement of adenosine triphosphate (ATP) contents and transmission electron microscope showed that disruptions of the cell wall and elution of intracellular ATP are assumed to be due to the bactericidal activity. In addition, the n-hexane fraction of Dryopteris crassirhizoma Nakai showed the strong growth inhibitions at 50 ppm on Vibrio parahaemolyticus and Bacillus cereus, and at 25 ppm on Staphylococcus aureus.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.40-46
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• 2000

To select the effective fungicides for the control of leaf spot disease of jujube tree (Zizyphus jujuba) caused by Phoma sp., inhibitory effects of 26 fungicides for mycelial growth were investigated at $250{\mu}g\;a.i./m{\ell}$. In the test, eight fungicides were selected and minimum inhibitory concentration (MIC) for mycelial growth and an inhibitory effect for spore germination were investigated. Among the fungicides, myclobutanil, hexaconazole, and triflumizole were excluded in control effect tests because of their relatively high MICs. MICs were ranged $10-50{\mu}g\;a.i./m{\ell}$ for benomyl, carbendazim + kasugamycin (CK), and thiophanate-methyl. triflumizole (TT), and $50-250{\mu}g\;a.i./m{\ell}$ for iprodione + propineb (IT) and iminoctadine-triacelate (IT). However, benomyl and IP showed very low inhibitory effect on conidial germination. When the fungicides were sprayed on the seedlings before the leaves were inoculated with conidial suspension of Phoma sp., the protective values of CK and TT were around 70% at 1,000 ppm and around 90% at 2,000 ppm. The protective values were around 70% at 2,000 ppm (benomyl), 4,000 ppm (IP), and 8,000 ppm (IT). When the fungicides were sprayed after inoculation, benomyl showed the highest curative values of over 90% at 1,000 ppm and the values of CK and TT ranged $70{\sim}80%$ at 1,000 ppm. However, IP and IT had little or no effect on therapy of the disease. IT caused necrotic phytotoxicity on the leaves of jujube seedlings. As results, the best fungicides for the protection of jujube trees from leaf spot disease were CK (2,000 ppm) and TT (2,000 ppm) and for the remedy of the tree, benomyl (1,000 ppm) was the best. Therefore, alternate application of benomyl and CK or TT will be effective in the disease control.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.333-341
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• 2016

To evaluate the possibility as a natural preservative of Cornus officinalis seed extracts, we investigated the anti-microbial activity and preservation effect of cosmetics. Cornus officinalis seed extracted with 1,3-Butylene Glycol(1,3-BG) and Ethanol(EtOH). As a result, Cornus officinalis seed extracts showed anti-microbial activity at Staphylococcus aureus, Staphylococcus epidermidis, Propionibacterium acnes and Cornus officinalis seed 1,3-BG extracts(COS-A) showed $26.7{\pm}4.0mm$ clear zone at the $1000.0{\mu}l/ml$. Minimum inhibitory concentration of S. epidermidis was observed at Cornus officinalis seed EtOH extracts(COS-B) $25.0{\mu}l/ml$. The result of challenge test for preservation effect on cosmetics, S. aureus and S. epidermidis was 100% eliminated from emulsion containing COS-A and COS-B after 7 days. These results suggest that Cornus officinalis seed extracts may have possibility as the natural preservative instead of synthetic perservative on cosmetics.

• Journal of Life Science
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• v.12 no.6
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• pp.803-811
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• 2002

The present study was carried out for research and development of natural antimicrobial from extract of Stachys sieboldii MIQ against food borne bacteria. The hexane extract of Stachys sieboldii MIQ at 250$\mu\textrm{g}$/$m\ell$ per disc showed 15 ~ 20 mm inhibition zone against gram positive and gram negative barteria. Minimum inhibitory concentration (MIC) of hexane extract was 250${\mu}g$/$m\ell$against Bacillus cereus, 250~500${\mu}g$/$m\ell$against Listeria monocytogenes, 500${\mu}g$/$m\ell$ against Staphylococcus aureus, Psedomonas aeruginosa. Observation by transmission electron microscope, showed that disruption of the cell wall assumed to be due to the bactericidal activity. In addition, the membrane integrity of the sensitive cells was disrupted by exposure to Stachys sieboldii MIQ extract on the D-$\beta$-galatosidase activity as substrate of O-nitrophenol-$\beta$-D-galacto-pyranoside. The hexane extract of Stachys sieboldii MIQ was very stable on the pH and thermal stability.