• Journal of Applied Biological Chemistry
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• 제66권
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• pp.73-80
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• 2023

일반적으로 여러 다양한 지방산들은 넓은 범위의 미생물들에 대해 항균활성을 나타내는 것으로 알려져 있다. 그러나 지방산의 구조에는 다양한 구조적 차이가 있음에도 불구하고 지방산의 구조적 차이에 따른 항균활성의 변화에 대해서는 많이 알려져 있지 않다. 본 연구는 중쇄지방산들을 대상으로 카복실기의 숫자와 위치에 따른 항균활성의 차이를 잘 알려져 있는 식중독균들을 대상으로 조사하였다. 전반적으로 단일카복실기를 갖는 중쇄 지방산이 이중카복실기를 갖는 중쇄지방산에 비해 더 강한 항균활성을 나타내었지만 두 종류의 중쇄지방산 모두 일반 항생제들과 함께 사용될 경우 매우 높은 시너지 효과를 나타낸다는 사실이 추가적으로 확인되었다.

• Journal of Korean Academy of Oral Health
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• 제42권4호
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• pp.210-215
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• 2018

Objectives: The main objectives of this study were to verify the antibacterial activity of two essential oils, lavender and peppermint, against dental caries and to review their synergistic effect when used in combination. Our results provide basic data for the evaluation of the use of these two substances towards the prevention and cure of dental caries. Methods: The sample solutions of lavender and peppermint oils were prepared in three different concentrations (30%, 50%, and 70% (v/v)) by diluting them with third-distilled water and Tween 20. Streptococcus mutans was selected as the bacterial species for testing. The disk diffusion method was used to measure the antibacterial activity of the sample solutions. For generating growth curves and measuring the number of clusters of the bacterial, the liquid medium-dilution method was used; the absorbance of the medium was measured at 600 nm after 3, 6, 12 and 24 hours. Results: When the antibacterial activity of the oils was tested via the disk diffusion method, the activity improved with increasing concentrations of all the sample solutions of peppermint, lavender, and the blend, but there was no significant difference between them with respect to the type of oil. In the growth curves of S. mutans, growth inhibition was observed after 12 hours. The inhibitory effect of 30% lavender oil on growth was 64.9% and 80.1% after 12 and 24 hours of treatment, respectively whereas that of peppermint oil was 71.3% and 80.1% after 12 and 24 hours of treatment, respectively. The inhibitory effect of the blended oil was 71.9% and 81.0% after 12 and 24 hours of treatment, respectively. Conclusions: Further research is still required in order to determine the efficacy of lavender and peppermint oils, as well as other essential oils, for wider use in preventing dental caries.

• Journal of Animal Science and Technology
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• 제65권1호
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• pp.225-243
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• 2023

Large amounts of additives are used during meat product processing to maintain product quality and shelf life. With the growing interest in healthy foods, natural plant-based additives are being used as alternatives to synthetic additives. In this study, six types of natural extracts with excellent antibacterial activity were selected, and their antibacterial and antioxidant activities against four types of pathogens were evaluated in various combinations. In addition, the pH, color, amount of thiobarbituric acid reactive substances (TBARS), and growth of pathogenic microorganisms were analyzed during the storage of sausages treated with various combinations of these extracts. The natural extract mixtures exhibited different antibacterial activities, depending on the combination. Compared to grapefruit seed extract, a mixture of natural extracts extracted with ethanol (M4) reduced the Escherichia coli content by more than 99.9% after 8 days of storage and slowed the growth of Listeria monocytogenes and Salmonella spp. by more than 80% after 14 days. Compared to untreated (NC) and grapefruit extract (PC)-treated sausages, sausages treated with the natural extract mixtures showed a significant decrease in CIE L^* and an increase in CIE a^* and CIE b^* (p < 0.05). The pH value was significantly lower in sausages containing natural extract mixtures than in the NC and PC sausages (p < 0.05). The natural plant extract mixtures significantly prevented lipid oxidation (p < 0.05). In summary, different types of natural extract mixtures have a synergistic effect when used together, suggesting that natural preservatives can generally inhibit the growth of microorganisms and oxidation of processed meat.

• 대한임상검사과학회지
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• 제49권3호
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• pp.256-262
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• 2017

식물로부터 유래되는 휘발성 유기 화합물인 에센셜 오일은 인체에 약리효과를 나타낸다고 알려져 있다. 본 연구에서는 화농성 질환과 병독성 질환 비뇨기계통 감염에 나올 수 있는 병원성 세균 Staphylococcus aureus (그람양성알균), Escherichia coli (그람음성막대균), Pseudomonas aeruginosa (그람음성막대균, 극성단모균)을 대상으로 천연 허브 오일 중에 비교적 많이 알려져 있는 라벤더(lavender), 티트리(tea tree), 로즈마리(rosemary), 멜리사(melisa) 4종류의 단일 오일과 비교해, 티트리와 로즈마리, 멜리사를 블렌딩하였을 때 항균력이 상승되는 효과가 있는지 연구하였다. 그 결과 디스크 확산법에서 블렌딩 오일(티트리, 로즈마리, 멜리사)의 경우 단독의 허브오일보다 S. aureus에서18 mm, E. coli 에서 22 mm 와 P. aeruginosa는13 mm의 우수한 항균능력을 확인할 수 있었다. 뿐만 아니라 블렌딩 오일의 경우 최소억제농도(Minimum Inhibitory Concentrations, MIC) 분석에서 S. aureus, E. coli 에서는 0.3125%에서, P. aeruginosa는 1.25%에서 성장억제효과가 확인되었다. 따라서 본 실험에서는 블렌딩 오일이 Oxacillin과 로즈마리, 티트리보다 항균효과가 우수한 것으로 증명되어 단독의 허브오일보다 블렌딩 오일이 우수한 항균력을 나타나는 것을 확인할 수 있었다. 그러므로 허브의 블렌딩을 활용하면 다제 내성균에 대한 항균시너지효과를 발휘할 수 있음을 입증했을 뿐만 아니라 향후 천연보존제와 건강기능성 식품 및 화장품에 활용 가능성을 기대해본다.

• Restorative Dentistry and Endodontics
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• 제39권4호
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• pp.288-295
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• 2014

Objectives: This study was designed to evaluate the synergistic antibacterial effect of xylitol and ursolic acid (UA) against oral biofilms in vitro. Materials and Methods: S. mutans UA 159 (wild type), S. mutans KCOM 1207, KCOM 1128 and S. sobrinus ATCC 33478 were used. The susceptibility of S. mutans to UA and xylitol was evaluated using a broth microdilution method. Based on the results, combined susceptibility was evaluated using optimal inhibitory combinations (OIC), optimal bactericidal combinations (OBC), and fractional inhibitory concentrations (FIC). The anti-biofilm activity of xylitol and UA on Streptococcus spp. was evaluated by growing cells in 24-well polystyrene microtiter plates for the biofilm assay. Significant mean differences among experimental groups were determined by Fisher's Least Significant Difference (p < 0.05). Results: The synergistic interactions between xylitol and UA were observed against all tested strains, showing the FICs < 1. The combined treatment of xylitol and UA inhibited the biofilm formation significantly and also prevented pH decline to critical value of 5.5 effectively. The biofilm disassembly was substantially influenced by different age of biofilm when exposed to the combined treatment of xylitol and UA. Comparing to the single strain, relatively higher concentration of xylitol and UA was needed for inhibiting and disassembling biofilm formed by a mixed culture of S. mutans 159 and S. sobrinus 33478. Conclusions: This study demonstrated that xylitol and UA, synergistic inhibitors, can be a potential agent for enhancing the antimicrobial and anti-biofilm efficacy against S. mutans and S. sobrinus in the oral environment.

• 한국동물위생학회지
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• 제40권3호
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• pp.219-225
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• 2017

This study was investigated the synergistic effects from the combination of cefalexin and gentamicin (CCG) against Staphylococcus spp. isolated from bovine milk. Minimum inhibitory concentrations (MICs) and fractional inhibitory concentration (FIC) index were determined for 16 bacteria from 13 bovine farms in Gyeongsangnam province by the National Committee for Clinical Laboratory Standards broth microdilution procedure. Antimicrobial agents tested included cefalexin, gentamicin and CCG. Against Staphylococcus spp. tested, the MIC ranges of cefalexin, gentamicin and CCG were 0.25~1.0, 0.5~0.125 and $0.06{\sim}0.125{\mu}g/mL$, respectively. In addition, the FIC index ranges of CCG against most of the isolates was 0.28~0.43 and the FIC index of CCG against 2 strains of Staphylococcus haemolyticus (S. haemolyticus) was 0.59. In conclusion, CCG has a high antibacterial activity against Staphylococcus isolates, then the combination may be applied for the treatment of bovine mastitis caused by Staphylococcus spp.

• Journal of Veterinary Science
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• 제19권6호
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• pp.808-816
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• 2018

Bacterial biofilms have been demonstrated to be closely related to clinical infections and contribute to drug resistance. Berberine, which is the main component of Coptis chinensis, has been reported to have efficient antibacterial activity. This study aimed to investigate the potential effect of a combination of berberine with ciprofloxacin (CIP) to inhibit Salmonella biofilm formation and its effect on expressions of related genes (rpoE, luxS, and ompR). The fractional inhibitory concentration (FIC) index of the combination of berberine with CIP is 0.75 showing a synergistic antibacterial effect. The biofilm's adhesion rate and growth curve showed that the multi-resistant Salmonella strain had the potential to form a biofilm relative to that of strain CVCC528, and the antibiofilm effects were in a dose-dependent manner. Biofilm microstructures were rarely observed at $1/2{\times}MIC/FIC$ concentrations (MIC, minimal inhibition concentration), and the combination had a stronger antibiofilm effect than each of the antimicrobial agents used alone at $1/4{\times}FIC$ concentration. LuxS, rpoE, and ompR mRNA expressions were significantly repressed (p< 0.01) at $1/2{\times}MIC/FIC$ concentrations, and the berberine and CIP combination repressed mRNA expressions more strongly at the $1/4{\times}FIC$ concentration. The results indicate that the combination of berberine and CIP has a synergistic effect and is effective in inhibiting Salmonella biofilm formation via repression of luxS, rpoE, and ompR mRNA expressions.

• Journal of Microbiology and Biotechnology
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• 제31권12호
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• pp.1656-1666
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• 2021

Dental pathogens lead to chronic diseases like periodontitis, which causes loss of teeth. Here, we examined the plausible antibacterial efficacy of copper nanoparticles (CuNPs) synthesized using Cupressus macrocarpa extract (CME) against periodontitis-causing bacteria. The antimicrobial properties of CME-CuNPs were then assessed against oral microbes (M. luteus. B. subtilis, P. aerioginosa) that cause periodontal disease and were identified using morphological/ biochemical analysis, and 16S-rRNA techniques. The CME-CuNPs were characterized, and accordingly, the peak found at 577 nm using UV-Vis spectrometer showed the formation of stable CME-CuNPs. Also, the results revealed the formation of spherical and oblong monodispersed CME-CuNPs with sizes ranged from 11.3 to 22.4 nm. The FTIR analysis suggested that the CME contains reducing agents that consequently had a role in Cu reduction and CME-CuNP formation. Furthermore, the CME-CuNPs exhibited potent antimicrobial efficacy against different isolates which was superior to the reported values in literature. The antibacterial efficacy of CME-CuNPs on oral bacteria was compared to the synergistic solution of clindamycin with CME-CuNPs. The solution exhibited a superior capacity to prevent bacterial growth. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and fractional inhibitory concentration (FIC) of CME-CuNPs with clindamycin recorded against the selected periodontal disease-causing microorganisms were observed between the range of 2.6-3.6 ㎍/ml, 4-5 ㎍/ml and 0.312-0.5, respectively. Finally, the synergistic antimicrobial efficacy exhibited by CME-CuNPs with clindamycin against the tested strains could be useful for the future development of more effective treatments to control dental diseases.

• 한국축산식품학회지
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• 제43권5호
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• pp.751-766
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• 2023

Helicobacter pylori is a bacterium that naturally thrives in acidic environments and has the potential to induce various gastrointestinal disorders in humans. The antibiotic therapy utilized for treating H. pylori can lead to undesired side effects, such as dysbiosis in the gut microbiota. The objective of our study was to explore the potential antibacterial effects of nisin and lactic acid (LA) in yogurt against H. pylori. Additionally, we investigated the anti-inflammatory effects of nisin and LA in human gastric (AGS) cells infected with H. pylori. Nisin and LA combination showed the strongest inhibitory activity, with confirmed synergy at 0.375 fractional inhibitory concentration index. Also, post-fermented yogurt with incorporation of nisin exhibited antibacterial effect against H. pylori. The combination of nisin and LA resulted in a significant reduction of mRNA levels of bacterial toxins of H. pylori and pro-inflammatory cytokines in AGS cells infected with H. pylori. Furthermore, this also increased bacterial membrane damage, which led to DNA and protein leakage in H. pylori. Overall, the combination of nisin and LA shows promise as an alternative therapy for H. pylori infection. Additionally, the incorporation of nisin into foods containing LA presents a potential application. Further studies, including animal research, are needed to validate these findings and explore clinical applications.

• 생명과학회지
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• 제27권6호
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• pp.611-616
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• 2017

식중독의 원인 세균 및 병원성 세균 7종(Bacillus cereus (11.2, 20), Clostridium perfringens (2.4, 4.7), Escherichia coli (9.1, 9.1), Listeria monocytogenes (11.1, 20), Salmonella typhi (4.7, 9.1), Staphylococcus aureus (2.4, 4.7), Vibrio parahaemolyticus (2.4, 5.3))에 대해 한약재 추출물의 항균 활성을 측정하였다. 추출물은 증류수를 이용한 고온추출법($121^{\circ}C$에서 30분간)으로 제조하였고, 9가지 한약재 추출물의 수율은 0.5-33.4% 범위였다. 종이 디스크 확산법을 이용하여 박테리아에 대한 항균 활성을 평가하였을 때 황련, 지유, 오배자 추출물에서만 항균활성이 나타났다. 황련과 지유 추출물은 Clostridium perfringens과 Listeria monocytogenes에만 항균활성을 나타낸 반면, 오배자는 시험한 모든 세균에 대해 강한 항균 작용을 보였다. 오배자 추출물의 건조시료가 나타내는 최소억제농도(MIC)와 최소살균농도(MBC)는 2.4~20 mg/ml 범위였다. 본 연구결과는 추후 정제와 항균물질에 대한 연구를 통하여 기존 항균제의 보완제 및 식품의 유통기한 증진 등 항균소재로서 응용이 가능할 것으로 기대된다.