• Korean Journal of Pharmacognosy
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• v.53 no.2
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• pp.87-95
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• 2022

Methicillin resistance Staphylococcus aureus (MRSA) is a gram-positive bacterium, the most commonly isolated bacterial human pathogen. JiYu-san is one of the natural products used to treat diseases in the folk recipe. In this study, we investigated the antimicrobial activity of EtOH 70% extracts of JiYu-san (JYS) against MRSA. The antibacterial activity of JYS against MRSA strain was evaluated using minimum inhibitory concentration (MIC), checkerboard dilution test, and time-kill assay. The effect of JYS on the immune mechanism of MRSA was confirmed through cell membrane permeability tests and energy metabolism tests, and the antibacterial activity mechanism was performed using qRT-PCR and western blot. As a result, in the antibacterial test of JYS, the MIC was measured to be 1.9~1000 ㎍/mL, and synergistic or showed a partial synergistic effect. In addition, JYS showed antibacterial activity in a combination test with DCCD or TX-100. In a study on the mechanism of action of antibacterial activity, it was found that JYS suppressed MRSA resistance genes and proteins. These results suggest that JYS has antibacterial activity and provides great potential as a natural antibiotic by modulating the immune mechanism against MRSA.

• Journal of Environmental Science International
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• v.27 no.1
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• pp.47-53
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• 2018

In this study, high-purity silver nanocolloids were synthesized by an electrolytic reaction, and the effect of temperature on the nanocolloid concentration was analyzed by performing the reaction at $70^{\circ}C$ and $90^{\circ}C$. The antibacterial properties of the thus-synthesized silver nanocolloids were also studied. When the synthesis was performed at $90^{\circ}C$, the concentration of silver nanocolloid increased to 14 mg/L after 5 min, 1756 mg/L after 30 min, and 2147 mg/L after 60 min. The concentration of silver nanocolloid synthesized by electrolytic reaction at $70^{\circ}C$ and $90^{\circ}C$ for 60 min was 1,882 mg/L and 2147 mg/L, respectively. The preferred temperature at which the electrolytic synthesis is performed is $70^{\circ}C$ to obtain high concentrations of 1,000 mg/L or more. The antibacterial performance of the thus-synthesized silver nanocolloids was 99.9% for E. coli and 99.5% for Pseudomonas aeruginosa.

• Journal of Environmental Health Sciences
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• v.35 no.5
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• pp.362-364
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• 2009

The present study was undertaken to estimate the antibacterial effect of Mume Fructus water extract (MFWE) against murine salmonellosis. At MFWE concentrations ranging from 25 to 100 ${\mu}g/ml$, the antibacterial effect was not showed on Salmonella typhimurium (S. typhimurium). On the other hand, bacteria without MFWE had a tendency to proliferate up to 8 h after incubation. Oral administration of MFWE at the dose of 40 mg/ml showed a therapeutic effect for S. typhimurium infected BALB/c mice. The mortality of MFWE-treated mice was 80% at 12 days, while that of MFWE-untreated mice was 100% at 9 days after a lethal dose of S. typhimurium infection. The results of our study strongly indicate that MFWE has potential as an effective of salmonellosis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.815-822
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• 2016

The cationic biopolymer chitosan has several applications in medicine. Chitosan is the deacetylated derivative of chitin, the second most abundant naturally occurring polymer. Recent studies have investigated the relationship between chitosan and antibacterial activity. However, the molecular interactions and mechanisms have not been detailed. This study used molecular dynamics simulations to study interactions between chitosan and anionic bacterial membranes (POPE-POPG) and electrically neutral non-bacterial membranes (POPC). We calculated the free energy using umbrella sampling to compare the interactions between membranes and chitosan in different protonation states. Fully protonated chitosan interacted most strongly with the bacterial membranes, but weakly with non-bacterial membranes. These results suggest that electrostatic interactions are the main mechanism of the antibacterial activity of chitosan, and they provide insights into the design of novel antibacterial and antimicrobial agents.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3605-3610
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• 2010

In the present study, some quinoline derivatives have been synthesized like 8-methoxy-4-methyl-2-amino-(3'-chloro-2'-oxo-4'-substituted aryl-1'-azetidinyl)quinolines 8-12 and 8-methoxy-4-methyl-2-amino-(2'-substituted aryl-4'-oxo-1',3'-thiazolidin-3'-yl) quinolines 13-17 from 8-methoxy-4-methyl-2-(substituted arylidenyliminoamino)-quinolines 3-7. The structural assignments of these compounds were based on spectral (IR, $^1H$-NMR, Mass) and elemental (C, H, N) analysis. Further, these compounds were evaluated for antibacterial activity against various bacterial strains. Three compounds 10, 11 and 16 were found to exhibit potent antibacterial activity as compared to the standard drug amphicillin.

• The Journal of Korean Medicine
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• v.23 no.3
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• pp.223-232
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• 2002

Objectives : Methicillin-resistant Staphylococcus aureus (MRSA) CCARM 3251 and S. aureusKCTC 1928 have been known to be resistant to many kinds of antibiotics. The extract of Glycyrrhizae Radix showed antibacterial activity against MRSA and antibiotics-resistant S. aureus. Methods : We examined the effects of the water-soluble extract and the methanol-soluble extract of Glycyrrhizae Radix on MRSA and antibiotic-resistant S. aureus. The methanolic extract was further fractionated with organic solvents such as hexane, chloroform, and ethyl acetate in that order. Results and Conclusions : The methanol-soluble extract of Glycyrrhizae Radix showed relatively high antibacterial activity against MRSA and antibiotic-resistant S. aureus. However, the water-soluble extract of Glycyrrhizae Radix showed no antibacterial activity against MRSA and antibiotic-resistant S. aureus. Among the fractions tested, the chloroform fraction showed the highest antibacterial activity against MRSA and antibiotic-resistant S. aureus. The methanol-soluble extract of Glycyrrhizae Radix minimal inhibitory concentrations (MICs) against MRSA and antibiotics-resistant S. aureus were $5{\;}mg/m{\ell}$ in both. The methanol-soluble extract of Glycyrrhizae Radix was separated using thin-layer chromatography and detected with UV -detector. Further study should be carried out to identify which effects cell growth inhibition of MRSA and antibiotics-resistant S. aureus.

• Food Science of Animal Resources
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• v.38 no.1
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• pp.172-179
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• 2018

One of the critical limitations to use of bacteriocins produced by lactic acid bacteria as a substitute for chemical antibiotics is the narrow spectrum of their antibacterial activity. The aim of present study was isolation and molecular identification of bacteriocin-producing enterococci with broad antibacterial spectrum. Bacteriocin-producing bacteria were isolated from native dairies in Kerman. Bacteriocins were purified by ammonium sulfate method and the effects of them were investigated on different strains of bacteria. Also, the effects of pH and heat on produced bacteriocins were investigated. High level bacteriocin-producing isolates were identified based on molecular tests. A total of 15 strains of bacteriocin-producing Enterococcus were isolated initially. Enterococcus faecium C-2 and Y-1 strains produced bacteriocins with the highest antibacterial effect. The bacteriocins were stable in pH ranges from 2 to 12 and their antibacterial activity was maintained after autoclave treatment. The maximum bactericidal effect was observed against Listeria monocytogenes and Pseudomonas aeruginosa. In conclusion, use of these bacteriocins as a substitute for chemical antibiotics is recommended.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.899-903
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• 2008

This study was conducted in order to elucidate the optimum conditions for the extraction of clove that can be used to elicit antibacterial activity against Streptococcus mutans using the evolutionary operation (EVOP)-factorial design technique. Higher antibacterial activity was achieved in a higher extraction temperature of $80^{\circ}C$ ($r=0.7983^{**}$) and in a longer extraction time of 26 hr ($r=0.6867^*$). Antibacterial activity was not effected by differentiation of ethanol concentration in the extraction solvent (r=-0.0683). The maximum antibacterial activity of clove against S. mutans as determined by the EVOP-factorial design technique was obtained at an extraction temperature of $80^{\circ}C$, an extraction time of 26 hr and a 50% ethanol concentration. Furthermore, the population of S. mutans decreased from an initial concentration of 6.850 to 4.195 log CFU/mL in the third set that is more than 2.6 log cycles by EVOP-factorial design technique.

• Korean Journal of Medicinal Crop Science
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• v.20 no.5
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• pp.308-314
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• 2012

This study was carried out to investigate the antibacterial activity against pathogens of acne and the anti-inflammatory effect of 75% ethanol extract and its fractions from the leaves of Prunus sargentii. In the antibacterial activity by the disc diffusion assay, the extract showed the highest effect against Propionibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis in 5 mg/disc. However, the ethyl acetate fraction showed the highest antibacterial activity in 1 mg/disc. On the other hand, the hexane and chloroform fraction showed strong nitric oxide (NO) production inhibitory effect in lipopolysaccharide (LPS)-stimulated Raw 264.7 cell. In the cell viability of Raw 264.7 by MTT assay, the extract and all fractions were exhibited normal viabilities as nontoxic result. Consequently, the extract from the leaves of P. sargentii and its ethyl acetate fraction could be applicable to functional materials for antibacterial activity related fields. Moreover, the hexane and chloroform fraction could be applicable to candidate materials as anti-inflammatory agent.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.39-46
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• 1995

This study was carried out to investigate antibacterial activities of the green tea extract according to storage temperature as death velocity constant. The survey data were collected from seven green teas (2 Korean, 2 Japanese, 2 Chinease and 1 Vietnamese) and experimental strains were used E. coli No. 11234, Ent. aerogenes No. 11783, Ps. fiu. orescens No. 11210, S. marscens No. 11808, St. mutans No. 11823 and V. parahaernolyticus No. 11965. The experimental results obtained were as follows: 1. Antibacterial activities of the green tea extracts according to the strains were strikingly difference. That is, those of the samples appeared to be conspicuous on [St. mutans No. 11823 (Range of death velocity constant a day after, at 20$\circ$C 4.85~5.22) and V. parahaemolyticus No. 11965 (4.70~6.00) while E. coli No. 11234 (0.59~-0.30) and Ent. aerogenes No. 11783 (0.24~-0.11)] were not so. 2. To storage temperature at 5$\circ$C than that at 20$\circ$C, antibacterial activities of the green tea extract on Ps. fluorescens No. 11210, S. marscens No. 11808, E. coli No. 11234, and Ent. aerogenes No. 11783 were sensitived but St. mutans No. 11823 and V. parahaemolyticus No. 11965 were not related to those. 3. Antibacterial activities to the strains were increased within two days.