• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.708-712
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• 2011

This study was focused on the determination of antibacterial activity of $Scutellaria$ $baicalensis$ extract against antibiotic resistant bacteria($Salmonella$ Enteritidis, $Staphylococcus$ $aureus$ and enteroaggregative $E.$ $coli$). Extract of $Scutellaria$ $baicalensis$ were tested for antibacterial activity by paper disc methods. The $Scutellaria$ $baicalensis$ extract in 0.1 g/$m{\ell}$ and 0.2 g/$m{\ell}$ showed a significant antibacterial activity against antibiotic resistant bacteria. Minimum inhibitory concentration (MIC) of $Scutellaria$ $baicalensis$ extract were appeared to 2,048 ${\mu}g/m{\ell}$ at $S.$ Enteritidis, $S.$ $aureus$ and enteroaggregative $E.$ $coli$. Finally, the growth incubation curve was determined using $Scutellaria$ $baicalensis$ extract against $S.$ Enteritidis, $S.$ $aureus$ and enteroaggregative $E.$ $coli$. The growth of $S.$ Enteritidis was significantly inhibited within 10 hours by the addition of at least 10,000 ppm of $Scutellaria$ $baicalensis$ extract. The 10,000 ppm of $Scutellaria$ $baicalensis$ extract retarded the growth of $S.$ $aureus$ and enteroaggregative $E.$ $coli$ more than 10 hours. In conclusion, $Scutellaria$ $baicalensis$ extract might be useful to control antibiotic resistant bacteria $in$ $vitro$.

• Preventive Nutrition and Food Science
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• v.22 no.3
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• pp.203-210
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• 2017

The antioxidant and antimicrobial activities of three kinds of strawberry ethanol extracts from Robus corchorifolius L. f. (RCL), Rubus parvifolius L. var. parvifolius (RPL), and Duchesnea chrysantha Miq. (DCM) were investigated. The RPL was highest (P<0.05) in phenolic, flavonoid, and anthocyanin contents. 2,2-Diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activities of RPL and DCM extracts were higher than that of RCL (P<0.05). Hydrogen peroxide scavenging activity of RPL was high compared to DCM and RCL (P<0.05). RCL exhibited a significant (P<0.05) potent antioxidant activity in nitric oxide radical inhibition. Inhibition diameter zone (nearest mm) of extracts against the test bacteria ranged from 11.5 in RCL to 12.5 in DCM against Staphylococcus aureus, from 10.5 in RCL to 13.5 in DCM against Streptococcus pneumoniae, from 8.5 in DCM to 10.5 in RCL against Escherichia coli, and the same inhibition of 10 mm in three of the extracts against Klebsiella pneumoniae. However, there was no inhibition against fungi Aspergillus niger and Candida albicans. Three of the extracts had the same minimum inhibitory concentration values of 12.50, 12.50, and $6.25{\mu}g/mL$ against S. aureus, K. pneumoniae, and S. pneumoniae, respectively. On the other hand, MIC values of 12.50, 12.50, and $6.50{\mu}g/mL$ were recorded for RPL, DCM, and RCL against E. coli, respectively. The result of present study revealed that extracts from three kinds of strawberries could be potential candidates as antioxidant and antimicrobial sources for functional food industries.

• Mycobiology
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• v.45 no.1
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• pp.25-30
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• 2017

Metal-based drugs, such as 1,10-phenanthroline, have demonstrated anticancer, antifungal and antiplasmodium activities. One of the 1,10-phenanthroline derivatives compounds (1)-N-2-methoxybenzyl-1,10-phenanthrolinium bromide (FEN), which has been demonstrated an inhibitory effect on the growth of Candida spp. This study aimed to explore the in vitro antifungal activity of FEN and its effect on the membrane integrity of Candida albicans. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of FEN against planktonic C. albicans cells were determined using the broth microdilution method according to the Clinical and Laboratory Standards Institute guidelines. Cell membrane integrity was determined with the propidium iodide assay using a flow cytometer and were visualized using scanning electron microscopy (SEM). Planktonic cells growth of C. albicans were inhibited by FEN, with an MIC of $0.39-1.56{\mu}g/mL$ and a MFC that ranged from 3.125 to $100{\mu}g/mL$. When C. albicans was exposed to FEN, the uptake of propidium iodide was increased, which indicated that membrane disruption is the probable mode of action of this compound. There was cells surface changes of C. albicans when observed under SEM.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.40-44
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• 2018

An isolate capable of inhibiting the growth of gram-positive bacteria was obtained from the soil of Mushim stream, Cheongju. The isolate was identified as Pseudomonas otitidis PS by 16S rRNA gene sequence analysis. P. otitidis PS produced antibiotics as a secondary metabolite when cultured in 1% soybean meal with 0.5% glucose. The maximum yield was about 0.1%. The antibiotic substance of P. otitidis PS extracted using ethyl acetate displayed a minimum inhibitory concentration of $2{\mu}g/ml$ for Staphylococcus aureus KCTC 1261. The antibiotic substance produced an orange halo on chrome azurol S agar due to siderophore activity. Growth inhibition was decreased when the iron was depleted. Since the antibiotic activity was lost upon the addition of the reducing agent ascorbic acid or during anaerobic culture, it was considered that antibiotic of P. otitidis PS strain exerts its bactericidal effect by the generation of reactive oxygen species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.3
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• pp.220-226
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• 2014

Sixty-seven Vibrio parahaemolyticus isolates from surface seawater from the Wando area, on the southern coast of Korea, were analyzed for their susceptibility to 15 different antimicrobials and the presence of virulence genes. According to the disk diffusion susceptibility test, all of the strains studied were resistant to ampicillin and oxacillin, while decreasing percentages were resistant to vancomycin (64.2%), streptomycin (56.7%), amikacin (31.3%), kanamycin (22.3%), cephalothin (20.9%), erythromycin (10.4%), ciprofloxacin (4.5%), and tetracycline (3.0%). All of the strains were susceptible to five antimicrobials: chloramphenicol, gentamycin, nalidixic acid, sulfamethoxazole/trimethoprim, and trimethoprim. Fifty-nine isolates (88.1%) were resistant to three or more classes of antimicrobial and defined as multidrug resistant, and two strains were resistant to seven antimicrobial agents. The minimum inhibitory concentration (MIC) of the 67 V. parahaemolyticus isolates to ampicillin and oxacillin ranged from 512-2,048 and $64-512{\mu}g/mL$, respectively. All 67 isolates were also examined for the presence of the tdh and trh virulence genes using the polymerase chain reaction (PCR). However, no isolates possessed either tdh or trh. The VPA0477 (${\beta}$-lactamase) gene, present in all of the tested strains, was validated as a new specific marker gene in PCR assays for the accurate detection and identification of V. parahaemolyticus.

• Food Science and Preservation
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• v.10 no.1
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• pp.89-93
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• 2003

To develope natural food preservatives, ethanol and water extracts were prepared from the Lentinus edodes 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 concentration(MIC) for Escherichia coli were as low as 0.5 mg/mL. Antimicrobial activity of the ethanol extract was stable by the heating at 121$^{\circ}C$ for 15 min and not affected by pH. The ethanol extract of Lentinus edodes exhibiting high antimicrobial activity. The highest antimicrobial activity adjust bacteria tested was found in the ethylacetate fraction.

• KSBB Journal
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• v.25 no.2
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• pp.123-129
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• 2010

An endospore-forming, rod-shaped bacterium was isolated from forest soil samples collected at the Taebaek mountain of Gangwon province, Korea, and taxonomically characterized by physiological, biochemical and phylogenetic methods. Its 16S rRNA sequences showed the maximum similarity of 97% with B. amyloliquefaciens. In addition, the isolate BCNU 2002 was determined to have the ability to produce enzymes such as amylase, protease, gelatinase and catalase. The in vitro antifungal activity of Bacillus sp. BCNU 2002 was also examined against human pathogenic fungi such as Aspergillus niger, Candida albicans, Epidermophyton floccosum, Saccharomyces cerevisiae, Trichophyton mentagrophytes and Trichophyton rubrum. A maximum production level of antifungal substances of Bacillus sp. BCNU 2002 was achieved under aerobic incubation at $28^{\circ}C$ for 7 days in LB broth. BCNU 2002 showed strong antifungal activities against T. mentagrophytes and T. rubrum with the range of percentage inhibition from 56.25 to 63.23%. It was also confirmed that ethylacetate extract of cultured broth showed a strong antifungal activity against A. niger, C. albicans, S. cerevisiae and T. rubrum by agar diffusion method. The peptide fraction also exhibited broad antifungal spectrum against various pathogenic fungi. The minimum inhibitory concentration values for active extracts ranged between 125 ${\mu}g$/mL and 1000 ${\mu}g$/mL.

• The Korean Journal of Food And Nutrition
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• v.13 no.1
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• pp.36-44
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• 2000

Survival of pathogenic bacteris(S. aureus, L. monocytogenes, E. coli and S. typhimurium) in tryptic soy broth containing green tea water extract(GTW), green tea ethanol extract(GTE), potassium sorbate (PS) and sodium benzoate(SB) stored at various pH was evaluated. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts and preservatives adjusted to pH 5.5, 6.0, 6.5 and 7.0 was inoculated approximately 105 CFU/ml of pathogenic bacteria and incubated at 35$^{\circ}C$ for 24∼48 hours. Survival of bacteria was determined by viable cell counts of bacterial culture at each pH. Minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) of green tea extracts and preservatives against pathogenic bacteria were derived from survival curves of each bacteria. Antibacterial activities of green tea extracts increased with increasing pH but those of preservatives decreased with increrasing pH. S. aureus was the most sensitive strain to GTW and GTE but the most resistant to PS and SB. The MICs of green tea extracts to S. aureus were 0.52∼0.98% at pH 5.5∼6.0 and non inhibitory at pH 7.0. S. typhimurium was the most resistant to green tea extracts while the most sensitive to SB. The MICs of green tea extracts to S. typhimurium were 0.46∼1.62% at pH 5.5∼6.0 and 2% of PS was bactericidal at pH 5.5. 1.0∼2.0% of GTE were bactericidal to all strains tested except L. m9oncytogenes at pH 7.0. GTE was most efficient at inactivating pathogenic bacteria, generally followed by GTW, PS and SB.

• Journal of Korean society of Dental Hygiene
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• v.17 no.1
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• pp.111-122
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• 2017

Objectives: Coriolus versicolor is an edible mushroom with physiological activities that has been used in traditional medicine. The aim of this study was to investigate the antimicrobial activity of extracts obtained from Coriolus versicolor against oral pathogens. Methods: The antimicrobial activities of various extracts of Coriolus versicolor were examined by disc diffusion assay, and minimum inhibitory concentration (MIC) of these extracts were also was determined by broth dilution method. The growth inhibition effect of extracts was measured at 600 nm for 12 hrs against Streptococcus ratti, Streptococcus criceti, Aggregati--bacter actinomycetemcomitans, Actinomyces viscosus, and Actinomyces israelii. Results: Coriolus versicolor extracts showed antimicrobial activities against all nine oral pathogens through disc diffusion assay. The ethanol extract and ethyl acetate extract differed significantly compared with acetone extract against Streptococcus ratti, Streptococcus criceti, Actinomyces viscosus, Actinomyces israelii and Aggregatibacter actinomycetemcomitans (p<0.05). These extracts exhibited MIC ranges of 2.63 to >10.50 mg/ml against the tested bacteria. The ethanol extract from Coriolus versicolor showed lower MIC values of 2.63 to 5.25 mg/ml. According to the obtained growth curve, the extracts of Coriolus versicolor were more effective against Actinomyces viscosus. Conclusions: The acetone, ethanol, and ethyl acetate extracts from Coriolus versicolor showed antimicrobial activities against Streptococcus mutans, Staphylococcus aureus, Streptococcus sanguinis, Streptococcus sobrinus, Streptococcus ratti, Streptococcus criceti, Aggregatibacter actinomycetemcomitans, Actinomyces viscosus, and Actinomyces israeli.i Therefore, they could be considered as natural oral antimicrobial agents against oral pathogens.

• Journal of Applied Biological Chemistry
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• v.63 no.1
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• pp.61-67
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• 2020

Thirty-five edible plants were tested against oral bacteria (Streptococcus mutans, Lactobacillus casei, Staphylococcus epidermidis, Klebsiella pneumonia). The edible plants were extracted using 70% ethanol as a solvent. Among the thirty-five edible plants, hibiscus (Hibiscus sabdariffa) extract was selected as an effective antibacterial source because it showed the lowest minimum inhibitory concentration. The antimicrobial substances of hibiscus extract were very stable at acidic condition and at wide range of temperature 4-75 ℃. The total polyphenol and flavonoid contents of hibiscus extract were 130.5 and 25.7 mg/g, respectively. Also hibiscus extract showed a high degree of antioxidant activity.