• 한국치위생학회지
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• 제14권1호
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• pp.117-122
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• 2014

Objectives : The purpose of the study is to investigate the activities of Nelumbo nucifera leaf extracts on Streptococcus mutans, Streptococcus mitis, Streptococcus sobrinus, Porphyromonas gingivalis, Prevotella intermedia, and Treponema denticola. Methods : The inhibitory effect of lotus leaf extracts on the growth of oral bacteria was assessed in experiments with extracts from freshly harvested and pulverized lotus leaves and bacterial cultures of dental caries. Results : The results showed that N. nucifera extracts possess antimicrobial activity on all bacterial strains. The minimal inhibitory concentration (MIC) values varied from 4 mg/ml to 10 mg/ml against antimicrobial activity. The relative growth ratio (RGR) against of N. nucifera extracts were determined as 50% in concentration of 4.0 mg/ml. The extract of N. nucifera was effective in reducing on the glucosyltransferase (GTase) activity of six strains in vitro. Conclusions : Methanol extracts of lotus leaves showed antimicrobial effects on three bacterial species causing dental caries and three bacterial species causing periodontitis, as well as inhibitory effects on GTase activity.

• Journal of Applied Biological Chemistry
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• 제65권2호
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• pp.101-105
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• 2022

양파의 주요 flavonoid 성분인 quercetin에 대한 항균 활성은 일부 알려져 있으나, 식물 병원성 세균인 X. campestris와 E. carotovora에 대한 활성은 알려져 있지 않았다. 본 연구에서는 quercetin과 양파 추출물을 활용하여 이들 식물병원균에 대한 항균 활성과 농용 항생제인 streptomycin과의 synergistic 효과를 평가하였으나, E. carotovora에 대한 항균 활성은 없었다. 하지만, X. campestris에서는 다른 세균류에서 알려진 MIC보다 10배 이상 낮은 15.6 ㎍ mL^-1이었으며, MBC는 20.0 ㎍ mL^-1으로 X. campestris에 대해 높은 선택적 항균 활성을 확인할 수 있었다. 다만, 농업용 항생제로 사용중인 streptomycin과의 약효상승 효과는 없었다. 또한, quercetin은 양파껍질의 EtOAc와 EtOH 추출물로부터 확보할 수 있었으며, EtOAc 추출물에서 quercetin 순도가 높음을 확인하였고, 이에 따라 EtOH 추출물보다 2배 가량 높은 항균 활성(MIC = 500 ㎍ mL^-1)이 확인되었다.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2129-2140
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• 2017

Silibinin is the major active component of silymarin, extracted from the medicinal plant Silybum marianum. Silibinin has potent antibacterial activity; however, the exact mechanism underlying its activity has not been elucidated. Here, we investigated the novel mechanism of silibinin against Escherichia coli. Time-kill kinetic assay showed that silibinin possess a bactericidal effect at minimal inhibitory concentration (MIC) and higher concentrations (2-and 4-fold MIC). At the membrane, depolarization and increased intracellular $Ca^{2+}$ levels were observed, considered as characteristics of bacterial apoptosis. Additionally, cells treated with MIC and higher concentrations showed apoptotic features like DNA fragmentation, phosphatidylserine exposure, and caspase-like protein expression. Generally, apoptotic death is closely related with ROS generation; however, silibinin did not induce ROS generation but acted as a scavenger of intracellular ROS. These results indicate that silibinin dose-dependently induces bacterial apoptosis-like death, which was affected by ROS depletion, suggesting that silibinin is a potential candidate for controlling bacteria.

• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.984-988
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• 2003

The actinomycete strain KH-6l4 possessed strong antifungal activity, especially antagonistic to the rice blast fungus, Pyricularia oryzae. Diaminopimelic acid (DAP) type and morphological and physiological characteristics, examined by scanning electron microscopy (SEM), indicated that KH-614 belonged to the genus Streptomyces. Antifungal agent produced by this strain was found to be most active, when the strain was cultured in the presence of glucose, polypeptone, and yeast extract (PY) medium for 6 days at $27^{\circ}C$. Based on the spectral report data, MS and NMR, the antifungal agent was identified as cyclo(L-leucyl-L-prolyl). According to the antimicrobial activity test measured by minimal inhibitory concentration (MIC), the cyclo(1eu-pro) exhibited the activity against Candida albicans IAM 4905, Mucor ramannianus IAM6218, Rhizoctonia solani IFO 6218, Aspergilus fumigatus ATCC 42202, Glomerella cingulata IFO 9767, Trichophton mentagrophytes ATCC 18749, and Trichophyton rubrum ATCC 44766, the order of MIC values were 50, 12.5, 5, 50, 25, 5, $5\;\mu\textrm{g}/ml$, respectively. Specifically, cyclo(1eu-pro) was one of the most effective elements against Pyricularia oryzae IFO 5994 with the MIC value of $2.5\;\mu\textrm{g}/ml$, thus indicating that cyclo(leu-pro) is a potential antifungal agent.

• 한국식품영양과학회지
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• 제30권3호
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• pp.415-420
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• 2001

Eighteen kinds of medicinal edible herbs, which are nontoxic and has been widely used in traditional folk medicine, were extracted and antimicrobial activity of the extracts was investigated against various foodborne pathogens or food poisoning microorganisms. Among them, the ethanol extract of Quercus mongolica showed the strongest antimicrobial activities against Gram positive and Gram negative bacteria and followed by Quercus aliena and Quercus dentata, respectively. Thus, further study was conducted to determine the antimicrobial activity of Quercus species extracts. The plants were extracted with ethanol, methanol and water, respectively. The ethanol, methanol, and water extracts of Quercus mongolica leaf showed 10~21 mm inhibition zone against Gram positive and Gram negative bacteria at two thousand $\mu\textrm{g}$ per disc, but little antimicrobial activity was observed against fungi and yeast. The minimal inhibitory concentrations (MIC) of the ethanol extract of Quercus mongolica leaf was 250$\mu\textrm{g}$/mL against Bacillus cereus. Salmonella typhimurium, and Pseudomonas aeruginosa and 62.5~125 $\mu\textrm{g}$/mL against Staphylococcus aureus and Listeria monocytogenes, respectively.

• 생약학회지
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• 제34권4호통권135호
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• pp.293-296
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• 2003

This study was carried out to evaluate cytotoxic effects of Salvia miltiorrhiza extracts on NIH 3T3 fibroblasts and KB cell lines. Disruptions in cell organelles were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The comparison of $IC_{50}$ of values of Salvia miltiorrhiza extracts in KB cell lines showed that their susceptibility to these extracts decreased in the following order: hexane extract > chloroform extract > methanol extract> dichloromethane extract > ethyl acetate extract>ethanol extract by the MTT method. The dried roots of Salvia miltiorrhiza was extracted several solvents, and then antimicrobial activity was investigated. The minimal inhibitory concentrations (MIC's) of the extract against microorganisms were also examined. Amtimicrobial activity of ketoconazol as reference was compared to those of extracts of hexane, chloroform, dichloromethane, ethyl acetate, ethanol and methanol. The antimicrobial activity of all extracts from the sample had growth inhibition activity against gram-negative bacteria, gram-positive bacteria and fungi. These results suggest that the hexane and chloroform soluble extracts of Salvia miltiorrhiza may be a valuable choice for the studies on the tumor cell lines and growth inhibition activity.

• 한국수산과학회지
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• 제53권3호
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• pp.443-450
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• 2020

No established method can be used to select effective antibiotics in antibiotic susceptibility tests for fish bacterial pathogens quickly and accurately. Here, we established the optimal conditions for determining the minimal inhibitory concentration (MIC) of major fish bacterial pathogens (Streptococcus spp., Edwardsiella tarda, Vibrio spp., Aeromonas spp., and Pseudomonas spp.) using the KRAQ1 and CAMPY2 panels. The MIC panel used 18 antibiotics of two types and we conducted experiments to establish the optimal culture medium and temperature for each species. The optimal conditions for incubating Streptococcus spp. were in cation-adjusted Mueller-Hinton broth with TES buffer (CAMHBT) at 28℃, using 5% lysed horse blood (LHB) as recommended by the Clinical Laboratory Standards Institute. For Vibrio spp., the optimal culture conditions were 28℃ in CAMHBT supplemented with 1% NaCl. The optimal conditions for culturing E. tarda, Aeromonas spp., and Pseudomonas spp. were in CAMHBT at 28℃.

• 대한소아치과학회지
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• 제36권1호
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• pp.1-11
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• 2009

Essential oil은 식물로부터 추출한 휘발성의 호지방성 화합물로서 essential oil은 잠재적으로 항균, 항진균, 진경련, 항말라리아성, 곤충퇴치능력 등의 생물학적 효과를 가지고 있다. 본 연구에서는 다양한 방향식물에서 추출한 Citral, Pineole, Linalool, Eugenol, Limonene, Pinene 등으로 구성된 다섯종류의 essential oil을 사용하였으며, 여덟 군의 중요한 병원성 세균인 Streptococcus mutans(S. mutans), Staphylococcus aureus(S. aureus), Streptococcus sanguis(S. sanguis), Streptococcus anginosus(S. anginosus), Actinobacillus actinomycetemcomitans(A. actinomycetem- comitans), Streptococcus sobrinus(S. sobrinus), Staphylococcus epidermidis(S. epidermidis), Esherichia coli (E. coli)에 대한 저항성으로서 항균능력을 평가하였다. Essential oil의 항균능력은 용액희석방법을 사용하여 검사하였으며, essential oil 농도범위는 10 mg/mL, 5 mg/mL, 2.5 mg/mL, 1.25 mg/mL, 0.625 mg/mL, 0.516 mg/mL, 0.3125 mg/mL, 0.078 mg/mL, 0.039 mg/mL, 그리고 0.015 mg/mL였다. Essential oil은 용량 의존적으로 시험 균주의 성장을 효과적으로 억제하였으며, NM을 제외하고 R, LG, FR, O oil은 저농도에서 구강 병원성 미생물의 성장을 억제하였다. 또한 사용된 essential oil은 E.coli와 S. epidermidis의 성장에는 탁월한 억제효과를 보이지는 못했으나 구강 병원성 미생물에 대해서는 특별한 성장 억제효과를 나타냈다.

• International Journal of Oral Biology
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• 제38권4호
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• pp.149-154
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• 2013

In general, oleanolic acid (OA) and ursolic acid (UA) have antimicrobial effect against Gram-positive bacteria but not Gram-negative bacteria whereas sophoraflavanone G has antimicrobial activity against both bacterial types. However, the antimicrobial effects of OA, UA, and sophoraflavanone G against periodontopathogens have not been studied to any great extent. The aim of this study was to investigate antimicrobial effect of OA, UA, and sophoraflavanone G against 15 strains (5 species) of oral Gram-negative bacteria, which are the major causative bacteria of periodontal disease. The antimicrobial activity was evaluated by minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) determinations. OA and UA showed antimicrobial effects against all of the Porphyromonas gingivalis strains tested and also Prevotella intermedia ATCC $25611^T$. Interestingly, P. intermedia ATCC 49046 showed greater resistance to OA and UA than P. intermedia ATCC $25611^T$. In contrast, sophoraflavanone G had antimicrobial activity against all strains, with MIC and MBC values below $32{\mu}g/ml$, except Aggregatibacter actinomycetemcomitans. These results indicate that sophoraflavanone G may have potential for use in future oral hygiene products such as dentifrices and gargling solution to prevent periodontitis.

• 한국식품과학회지
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• 제22권6호
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• pp.716-719
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• 1990

카레에 사용되는 각종 향신료로부터 수증기증류법에 의하여 정유를 분리하고, 그람양성균, 그람음성균, 유산균, 효모 및 곰팡이에 대한 향균성을 검토하였다. 모두 14종의 향신료 정유의 항균력을 Agar diffusion법으로 실험하였으며, 항균력이 강한 5종(clove, cumin, nutmeg, oregano, rosemary)을 선별하여, 이들의 최소 생육억제 농도(MIC)를 측정하였다. 이들 5종의 향신료 정유성분들은 매우 낮은 농도($0.2{\sim}9\;mg/ml$)에서도 좋은 항균효과를 보였으며, 생육억제효과는 그람음성균보다 그람양성균에 좋았으나, 비록 그람양성균이지만 유산균에 대한 효과는 낮게 나타났다.