• Food Science of Animal Resources
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• v.37 no.4
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• pp.502-510
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• 2017

This study investigated bacterial growth-inhibitory effect of 69 therapeutic herbal plants extracts on 9 bacterial strains using a disc diffusion assay. Especially, the antimicrobial activity of Psoraleae semen, which showed different activity on pathogenic Gram-positive and Gram-negative bacteria, was evaluated by MIC (minimal inhibition concentration) and biofilm formation assay. The effect of Psoraleae semen extract on bacterial cell membranes was examined by measurement of protein leakage (optical density at 280 nm) and scanning electron microscope (SEM). No clear zone was formed on discs containing Gram-negative bacteria, but Gram-positive bacteria exhibited clear zones. The MICs of Psoraleae semen extract were $8{\mu}g/mL$ for Streptococcus mutans, and $16{\mu}g/mL$ for Enterococci and Staphylococcus aureus. In addition, biofilm formation was inhibited at concentration $8-16{\mu}g/mL$. Protein leakage values and SEM images revealed that cell membranes of Gram-positive bacteria were impaired following exposure to the extract. Further, the extract inhibited the growth of Listeria monocytogenes in sausages. These results indicate that Psoraleae semen extract could be utilized as a natural antimicrobial agent against Gram-positive bacteria.

• The Journal of Internal Korean Medicine
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• v.35 no.4
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• pp.455-471
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• 2014

Objectives: This experiment was done for investigating antimicrobial activity of Hwangryunheadok-tang and Scutellariae Radix extract, Phellodendri Cortex extract, Coptis Rhizoma extract, Gardenia Jasminoides extract against Staphylococcus aureus. Methods: After administering S. aureus on a bacterial culture media plate, antimicrobial activity was tested by dripping $80{\mu}l$ diluted Hwangryunheadok-tang and Scutellariae Radix extract, Phellodendri Cortex extract, Coptis Rhizoma extract, and Gardenia Jasminoides extract (100%, 50%, 10%, 1%) on plates that were cultivated for a span of time from 16 to 72 hours. Also, minimal inhibitory concentration (MIC) was tested by dripping the minimum dilution density solution that has antimicrobial activity between $80{\mu}l$ and $20{\mu}l$ ($80{\mu}l$, $60{\mu}l$, $40{\mu}l$, $20{\mu}l$) in measure of density. Antimicrobial activity of Hwangryunheadok-tang and four kinds of extracts against S. aureus was continually displayed. Results: 1. S. aureus (Standard Microorganism, ATCC) (1) Antimicrobial activity was displayed for Hwangryunheadok-tang, Scutellariae Radix extract, and Phellodendri Cortex extract respectively in the undiluted solution and 50% of diluted magnification. Gardenia Jasminoides extract showed its activity only in the undiluted solution; Coptis Rhizoma extract showed its activity down to 10% of diluted magnification. The antimicrobial activity of the undiluted solution was increased when the volume of inoculation increased. But, there was no difference when time was extended for cultivation. (2) MIC of Hwangryunheadok-tang, Scutellariae Radix extract was 50%, $20{\mu}l$. Coptis Rhizoma extract was 10%, $20{\mu}l$, Phellodendri Cortex extract was 50%, $80{\mu}l$ and Gardenia Jasminoides extract was 100%, $60{\mu}l$. 2. S. aureus isolated from diarrheal patients (1) When compared to standard microorganism, MIC has decreased. As a result, their antimicrobial activity has increased. (2) Antimicrobial activity of Hwangryunheadok-tang and four extracts was continually shown in extending of the time, 16, 24 and 72 hours. Conclusions: The author comes to the conclusion that Hwangryunheadok-tang, and four kinds of extracts have antimicrobial activity against S. aureus. Especially, when comparing standard microorganisms with S. aureus isolated from diarrheal patients, some cases showed that antimicrobial activity of all the extracts were better than antibiotics. Thus, if a further study is performed, the use of Hwangryunheadok-tang, and four kinds of extracts will be valuable and beneficial in clinical treatments.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.715-725
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• 2005

Oral streptococci are major constituents of dental plaques, and their prevalence is closely linked with various pathologic symptoms, such as dental caries. To develop natural anticaries agent, we prepared 309 kinds of plant extracts from 215 species of edible or medical plants, and antibacterial activity of the extracts against Streptococcus mutans JC-2 were evaluated based on 96 well microtiter plate assay and disk paper method, subsequently. Among the tested plant extracts, Ailanthus altissima, Paeonia lactiflora, Rubus phoenicolasius, Aralia continentalis, Quercus acutissima, Persicaria hydropiper and Agrimonia pilosa extracts showed strong antimicrobial activity. Determination of minimal inhibitory concentration (MIC) of the selected seven plant extracts showed that Ailanthus altissima, Persicaria hydropiper and Quercus acutissima extracts ($MIC=25\∼30[\mu}g/ml$) has potential as a source of natural anticaries agents.

• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1278-1283
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• 2007

The 30% resistant frequencies of pathogenic bacteria were identified against generally utilizing disinfectants. Among the used disinfectants, foodsef, Taego, and Iodo 175 were dictated by lower sensitivities against pathogenic bacteria, as well as higher resistant frequencies when compared with other disinfectants. The resistant frequencies against antibiotics were also dictated by 30% through MIC (minimal inhibitory concentration) and paper disc methods. Especially, the used bacteria exhibited resistances against gentamycin, kanamycin, and streptomycin, which included in all aminoglycoside group. The MBT-01108 material, which extracted and purified from a powder obtained by processing of Opunita ficus-indica var. saboten Makino trunk, did not develop or grow resistant bacteria. Interestingly, the multi-drug resistant bacteria such as MRSA, resistant Pseudomonas aeruginosa, VRE, and E. coli 0157 did not resistant against MBT-01108 material. These results suggest that MBT-01108 material uses as an anti-microbial agent.

• Korean Journal of Agricultural Science
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• v.19 no.2
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• pp.170-178
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• 1992

Isolates of Botrytis cinerea resistant to dicarboximide fungicides were collected from strawberry fields in greenhouses in spring and early summer of 1990. Five out of 9 isolates of B. cinera were resistant, which showed mycerial growth on PDA containing dicarboximide fungicides(procymidone and vinclozolin) with concentrations of 100, 400 and $1,600{\mu}g/ml$. The minimal inhibitory concentration(MIC) values of the dicaboximide-resistant isolates was more than $6,400{\mu}g/ml$, while that of the sensitive isolates was less than $6.25{\mu}g/ml$. The germination ratio of conidia of the resistant isolates on PDA containing procymidone and vincolozolin was more than 95%, while that of the sensitive was less than 15%. The procymidone-resistant isolates were also resistant to vinclozolin, showing cross-resistant between the fungicides, but cross-resistant was not observed between the dicarboximides and dichlofluanid. Resistance to benomyl was also found in all the dicarboximide resistant isolates. Occurrence frequency of dicarboximide-resistant isolates out of 223 isolates was about 40%. The resistant isolates were widely distributed throughout Korea.

• Korean Journal of Agricultural Science
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• v.23 no.1
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• pp.80-89
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• 1996

The expression and secretion of human lactoferrin (hLf) in Sacclnromyces diastaticus were performed. 1. For the secretion of hLf in yeast, recombinant plasmid pYEGLf was constructed using promoter, secretion signal sequence of glucoamylase I gene (STA1) and transcriptional terminator of GAL7 gene. 2. Each correct recombinant plasmid was selected by mini-preparation of plasmid DNA from E coli transformant and restriction enzyme digestion analysis. The selected plasmids, pYEGLf, were transformed into S. diastaticus YIY345 as a expression host, respectively. 3. Western blot analysis using rabbit anti-hLf was carried out to identify expressed hLf. Positive signals were shown in culture supernatant of pYEGLf transformant. 4. About $100{\mu}g-1mg$ of concentrated culture supernatant of positive clone were loaded on paper disc and tested for the antimicrobial activity against E coli. However, no activity was observed. We concluded that this fact results from low concentration of hLf secreted from yeast, compared with the fact that MIC of hLf is as high as $3mg/m{\ell}$. Therefore, the purification of secreted hLf may be require to investigate the antimicrobial activity. From this study, the feasibility of low-cost production of sufficient quantities of human lactofferin for nutritional and therapeutical applications were suggested.

• Journal of Veterinary Clinics
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• v.30 no.3
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• pp.172-177
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• 2013

The aim of this study was to evaluate the in vivo and in vitro efficacy of enrofloxacin-silver sulfadiazine (Baytril$^{(R)}$ otic, Bayer, USA) for the treatment of otitis externa in dogs. Twenty-four dogs with otitis externa were included in this double-blinded, randomized study. The experimental group was treated with the Baytril$^{(R)}$ otic and the distilled water was applied to the control group. Both groups were administered each solution twice daily for 7 days and next 7 days off treatment. On days 0, 7 and 14, clinical signs, bacteriological and fungal counts were graded using semi-quantitative scales, respectively. For the evaluation of in vitro efficacy of Baytril$^{(R)}$ otic, we also performed Minimal Inhibitory Concentration (MIC) test by agar dilution method against Staphylococcus pseudintermedius, Pseudomonas aeruginosa and Malassezia pachydermatis. In the experimental group, the sum of clinical scores was decreased 81.0% and microbial scores were significantly reduced 87.0% at days 14, compared with day 0. The results of MIC testing were showed the concentration of enrofloxacin and silver sulfadiazine in Baytril$^{(R)}$ otic is high enough to kill for 3 infectious agents. No adverse reactions were observed in any of the dogs during this study. These results suggest that Baytril$^{(R)}$ otic are efficient and safe treatment for canine otitis externa.

• YAKHAK HOEJI
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• v.49 no.4
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• pp.323-329
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• 2005

Antimicrobial peptides are evolutionary ancient weapons for animal and plant species to depend themselves against infectious microbes. In the present study, we investigated if an antimicrobial peptide was produced from Coptidis Rhizoma. For the determination, protein substance from the medicinal plant was isolated by various preparations. Among the preparations, the protein portion dissolved in phosphate-buffered saline solution (CRP-DS) that contained the most amount of protein $(90\%)$ resulted in maximal inhibition of Candida albicans which causes local and systemic infections. Analyses by gel-electrophoresis and gel-permeation chromatography showed the CRP-DS formed a single band of approximately 11.8 KDa as molecular size. Antifungal activity of the CRP-DS was almost equivalent to antifungal activity by fluconazole, resulting in MIC (minimal inhibitory concentration) of approximately $50{\mu}g/ml$. The antifungal activity was a dose-dependent. The antifungal activity appeared to be inactivated by heat-treatment and ionic strength, respectively. In a murine model, the CRP-DS enhanced resistance of mice against disseminated candidiasis. The HPLC analysis demonstrated maximum $4\%$ of berberine as residual content in the CRP-DS preparation resulted in no influence on the antifungal activity. In addition, protein portion isolated from Phellodendri Cortex producing the alkaloid component like Coptidis Rhizoma had no such anticandidal effect. These results indicate that the protein substance from Coptidis Rhizoma was responsible for the antifungal activity.

• Korean Journal of Veterinary Service
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• v.23 no.1
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• pp.19-28
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• 2000

There are several main antibacterial susceptibility tests, such as agar dilution method, broth dilution method and disk diffusion technique. Especially, for minimal inhibitory concentration (MIC) test, agar dilution method has been widely used. But that method is so complicated and bothering that it's difficult to treat a large amount of strains. On the other hand, modified broth dilution method(add 1% glucose and 0.018% phenol red as a pH indicator to broth) is fast and easy to perform. Most of all, it can visualize the result by color. The MICs of 22 antibiotics Including penicillins, aminoglycosides, cephalothin, chloramphenicol, lincomycin, ceftiofur, vancomycin and quinolones, erythromycin, colistin. sul-fadimethoxine, trimethoprim for arcanobacterium pyogenes 14 strains, actinobacillus pleuropneu-moniae 41 strains and pasteurella multocida 37 strains, which were collected from porcine during 1996 ∼ 1999, were determined by modified broth dilution method. Actinobacillus pleuropneumoniae was highly susceptible to all kinds of quinolones such as ciprofloxacin, enrofloxacin and norfloxacin and to all aminoglycosides, like gentamicin, apramycin, kanamycin and ampicillin, cephalothin and ceftiofur. But It was quite resistant to solfadimethoxin, colistin and vancomycin. Pasteurella multocida was found to have high susceptibility to ampicillin, cephalothin, chlorampenicol and gentamicin but had mid-degree susceptibility to other aminoglycosides. In addition, it was susceptible to norfloxacin and nalidixic acid, but not to newer fluoroquinolone like ciprofloxacin and enrofloxacin and it was resistant to colistin and kanamycin. Arcanobacterium pyogenes was highly susceptible to most of quinolones such as cipoofloxacin, enrofloxacin and norfloxacin and gentamicin and penicillin G. But it also obtained high resistance against the early quinolone, nalidixic acid and aminoglycosides such as amikacin, apramycin and kanamycin and erythromycin, chlorampenicol, tetracyclin and vancomycin.

• Journal of Life Science
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• v.13 no.5
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• pp.604-617
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• 2003

Candida albicans is one of the most common etiological agents in fungi-associated skin infections. There is an increase of candidiosis especially in the patient of acquired or induced immunodeficiency syndromes or in the event of long-term antibiotics and immuno-suppressor or cytotoxic therapies. To screen out reliable and effective anti-candidiosis agent, in this study, we have evaluated antifungal activity of 298 plant extracts against C. albicans. Based on the results of disc-paper method and determination of minimal inhibitory concentration, fifteen extracts were finally selected as possible sources of anti-candidiosis agent. Especially, six different plant extracts, such as Rubus parvifolius, Euphorbia pekinensis, Coptis chinensis, Eugenia aromaticum, Paeonia lactiflora var. hortensis and Paeonia suffruticosa showed strong antifungal activity against C. albicans, not to S. cerevisiae. These results suggested that medicinal and wild plants could be the potential source of antifungal agent.