• 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.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.748-756
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• 2016

In the present study, a lipopeptide (named AXLP14) antagonistic to Xanthomonas oryzae pv. oryzae (Xoo) was obtained from the culture supernatant of Bacillus amyloliquefaciens B014. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis demonstrated that AXLP14 consisted of surfactin homologs. The minimum inhibition concentration and minimum bactericidal concentration of AXLP14 against Xoo were determined to be 1.25 and 2.50 mg/ml, respectively. At a concentration of 0.613 mg/ml, AXLP14 strongly inhibited the formation of Xoo biofilm. AXLP14 also inhibited the motility of Xoo in a concentration-dependent manner. Applying AXLP14 to rice seedlings significantly reduced the incidence and severity of disease caused by Xoo. In Xoo-infected rice seedlings, AXLP14 strongly and continuously up-regulated the expression of both OsNPR1 and OsWRKY45. In addition, AXLP14 effectively inhibited the Xoo-induced up-regulation of the expression of the abscisic acid biosynthesis gene OsNECD3 and the abscisic acid signalingresponsive gene OsLip9, indicating that AXLP14 may protect rice against Xoo-induced disease by enhancing salicylic acid defense and interfering with the abscisic acid response to virulence.

• 한국임상수의학회지
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• 제34권4호
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• pp.261-267
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• 2017

The aim of this study was to investigate the antibacterial properties of chitosan silver nanocomposites (CAgNCs) using pathogenic Vibrio ichthyoenteri as a bacterial model. Results of agar disc diffusion and turbidimetric assays showed that CAgNCs could inhibit the growth of V. ichthyoenteri in concentration dependent manner. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CAgNCs were 75 and $125{\mu}g/mL$, respectively. Furthermore, CAgNCs treatment induced the reactive oxygen species (ROS) level in V. ichthyoenteri cells in concentration and time dependent manner, suggesting that it generates oxidative stress, leading to bacterial cell death. The field emission scanning electron microscope (FE-SEM) images of CAgNCs treated V. ichthyoenteri exhibited strong cell membrane damage than un-treated control bacteria. MTT assay results showed the highest cell viability (22%) at $75{\mu}g/mL$ of CAgNCs treated bacteria samples. The results from this study suggest that CAgNCs is a potential antibacterial agent to control fish pathogenic bacteria.

• 동의생리병리학회지
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• 제19권5호
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• pp.1233-1237
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• 2005

Catechin products in green tea extract was prepared to investigate antibacterial activity on the pathogenic bacteria. Survival of pathogenic bacteria (MASA - methicillin resistant Staphylocouus aureus, E.coli O157 and S. typhimurium Sal-13) in tryptic soy agar(TSA) containing Catechin products powder incubated at various concentration was evaluated. TSA containing $0{\sim}2%(w/v)$ of Catechin products was inoculated approximately $10^4\;CFU/ml$ of pathogenic bacteria and incubated at $37^{\circ}C$ for 24 hours. The plate counting technique and clear zoon test were used to test survival effect of the Catechin products. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was derived from the survival curves of pathogenic bacteria. S. typhimurium Sal-13 was the most sensitive strain to Catechin products. This result suggested that Catechin products can be used as an effective natural antibacterial agent.

• 대한약침학회지
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• 제19권4호
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• pp.312-318
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• 2016

Objectives: Bacterial resistant infections have become a global health challenge and threaten the society's health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus) and the standard strain of Pseudomonas aeruginosa (P. aeruginosa). Methods: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI). Results: The MICs of gentamicin against bacterial strains were in the range of $0.312-320{\mu}g/mL$. The MIC values of both types of catechins were $62.5-250{\mu}g/mL$. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1). A combination of caffeine with gentamicin did not alter the MIC values of gentamicin. Conclusion: The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains. Therefore, combinations of gentamicin with these natural compounds might be a promising approach to combat microbial resistance.

• 한국미생물·생명공학회지
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• 제38권4호
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• pp.405-413
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• 2010

무화과는 뽕나무 과에 속하며 세계에서 가장 오래된 과일 중 하나이고, 국내에서는 주로 소화장애, 염증성궤양 그리고 가려움증 등에 사용되어 왔다. 본 연구에서는 무화과 잎을 메탄올로 추출한 후 임상진료실에서 분리된 메티실린 내성 황색포도상구균(MRSA)에 대한 항균활성을 보았다. 그 결과 분리된 MRSA 1-20에서 최소억제농도 (MIC)는 2.5 mg/mL에서 20 mg/mL 농도로 측정되었으며, 최소살균농도(MBC)는 5 mg/mL에서 20 mg/mL 농도로 관찰되었다. Oxacillin이나 ampicillin과 병용투여 시 4-8배 이상의 MIC/MBC농도가 감소되었으며, FICI 값도 0.0375-0.5이하로 병용효과를 나타내었다. 더불어 메탄올추출물 단독 사용시 보다 항생제와 병용투여 시 빠른 사멸효과를 보였다. 결론적으로 무화과 잎이 메티실린 내성 황색포도상구균에 항균활성을 나타냄을 확인하였으며, 메티실린 내성 황색포도상구균 감염에 천연 치료제로서의 가능성을 확인하였다.

• 급식외식위생학회지
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• 제1권1호
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• pp.27-35
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• 2020

Salt is a common seasoning agent used in various processed foods, especially in kimchi and salted seafood (jeotgal). This study was conducted to investigate the efficacy of salt with antimicrobial substances (acetic acid, garlic extract, carvacrol, nisin, thymol, and their combination (acetic acid+nisin+thymol)) on improvement of antibacterial effects of salt against foodborne pathogens. Salt (10%) was prepared using six different types of 0.2% natural antimicrobial substances. The antibacterial effect of salt combined with natural antimicrobial substances was evaluated against foodborne pathogens using the broth micro-dilution method and growth curve plotted using absorbance measurements. For the five foodborne pathogens, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of salt without antimicrobial substances as control were in the range of 24~>50,000 ㎍/mL and >50,000 ㎍/mL, respectively. Salt with nisin, thymol, or garlic extract showed strong inhibitory effects and their MIC against L. monocytogenes were 49, 12,500, and 24 ㎍/mL, respectively. In particular, salt with nisin showed inhibitory activities against Gram-positive bacteria. However, all the antimicrobial substances were less effective against Gram-negative bacteria such as E. coli O157:H7 and S. Typhimurium than Gram-positive bacteria. These results could be used for the development of salt with natural antimicrobial substances especially targeted against L. monocytogenes. This would enable the lowering of saline concentration while improving the storability of food.

• 대한약침학회지
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• 제22권1호
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• pp.49-54
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• 2019

Objective: Antibiotic resistance is a global health problem and threatens health of societies. These problems have led to a search for alternative approaches such as combination therapy. The aim of the present study was to investigate the effect of caffeine and omeprazole in combination with gentamicin or ciprofloxacin against standard and clinically resistant isolates of Staphylococcus aureus and Escherichia coli. Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interaction of non- antibiotic drugs with gentamicin and ciprofloxacin was studied in vitro using a checkerboard method and calculating fraction inhibitory concentration index (FICI). Verapamil as efflux pump inhibitor was used to evaluate the possible mechanism of bacterial resistance to antibiotics. Results: The MIC and MBC values of gentamicin against bacterial strains were in the range of $20-80{\mu}g/ml$ and $40-200{\mu}g/ml$, respectively. Caffeine and omeprazole had no intrinsic inhibitory activity against tested microorganisms. However, upon combination of caffeine with antibiotics, the synergistic effects were observed. Verapamil was able to reduce the MIC values of gentamicin (4 folds) only in some bacterial strains. Conclusion: These findings indicated that caffeine was effective in removing bacterial infection caused by S. aureus and E. coli. The relevant mechanisms of antibiotic resistance were not related to the drug efflux.

• Advances in nano research
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• 제7권4호
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• pp.241-248
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• 2019

Recent researches demonstrated well promising anticancer activities for antibiotics. Such effects would be significantly increased while nanoparticle based delivery systems were applied. In this study, the goal was aim to improve anticancer and antitoxic effects of Streptomycin by loading on special kind of dendrimer (anionic-linear-globular second generation). In the current study, Size and zeta potential as well as AFM techniques have been used to prove the fact that the loading was performed correctly. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the drug loaded on dendrimer nanoparticle were determined and compared with both of dendrimer alone and free drug with respect to staphylococcus aureus as the test microorganism. The anticancer activity among three groups including Streptomycin, Streptomycin -G2 dendrimer, and control was measured in vitro. In vitro studies showed that G2 anionic linear-globular polyethylene-glycol-based dendrimer, which loaded on Streptomycin was able to significantly improve the treatment efficacy over clinical Streptomycin alone with respect to proliferation assay. Maximal inhibitory concentration (IC50) was calculated to be $257{\mu}g/mL$ for streptomycin alone and $55{\mu}g/mL$ for Streptomycin -G2 dendrimer. In addition, Streptomycin -G2 dendrimer conjugate prevented the growth of MCF-7 cancerous cells in addition to enhance the number of apoptotic and necrotic cells as demonstrated by an annexin V-fluorescein isothiocyanate assay. Streptomycin -G2 dendrimer conjugate was able to increase Bcl-2/Bax ratio in a large scale compared with the control group and Streptomycin alone. Based on results a new drug formulation based nano-particulate was improved against S. aureus with sustained release and enhanced antibacterial activity as well as anticancer activity shown for functional cancer treatment with low side effects.

• 한국축산식품학회지
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• 제39권3호
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• pp.418-429
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• 2019

This study was conducted to evaluate the antioxidant and antimicrobial activities of lyophilized extracts of scallions (Allium fistulosum L., SLE), garlic (Allium sativum, GLE), and gold kiwi (Actinidia chinensis, GKE) and their effects on the quality of chicken breast meat inoculated with L. monocytogenes during storage for 9 days at $4^{\circ}C$. The lowest minimum inhibitory concentration and minimum bactericidal concentration (25 and 100 mg/mL, respectively) against L. monocytogenes were observed for SLE and GLE, respectively. GKE had the lowest half-maximal inhibitory concentration ($IC_{50}$) for 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity (5.06 mg/mL). The pH values of meat inoculated with L. monocytogenes and dipped in 1% SLE (LSLE), 1% GLE (LGLE), or 1% GKE (LGKE) were lower than that of the control on day 3 of storage (p<0.05). The initial population of L. monocytogenes in meat was 4.95-5.01 Log CFU/g. However, the population in the LSLE (5.73 Log CFU/g) was lower than that in the control (6.23 Log CFU/g) on day 5 (p<0.05). The volatile basic nitrogen value of the LSLE (19.90 mg/100 g) was lower than that of the control (24.38 mg/100 g) on day 7 (p<0.05). Moreover, treatment with SLE resulted in the maintenance of meat quality and reduced the population of L. monocytogenes on the meat. Thus, SLE may be used as an alternative natural and environmentally friendly sanitizer for reducing L. monocytogenes contamination in the chicken meat industry.