• Archives of Pharmacal Research
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• v.15 no.3
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• pp.239-241
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• 1992

The methanol extract of Cinnamoni Cortex showed antibacterial action against cariogenic bacterium, Streptococcus mutans OMZ 176. The active principle of the extract was identified to be trans-cinnamaldehyde, which was bactericidal in the minimal inhibitory concentration (MIC) of $100\;\mu$g/ml against the strain. From the results of antibacterial activity of cinnamaldehyde and its derivatives, the acrolein group in the cinnamaldehyde was elucidated to be an essential element for the activity.

• Korean Journal of Microbiology
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• v.12 no.2
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• pp.85-93
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• 1974

Four stereoisomers of inositol p-aminosalicylate, that is hexaris-O-(p-aminosalicylyl)-myo-inositol, hexaris-O-(p-aminosalicylyl)-muco-inositol were synthesized by p-aminosalicylyl chloride with myo-, epi-, scyllo-, and muco-inositol respectively. Their antibacterial activity was tested against human type tubercle bacilli $H_{37}$/Rv, in contrast to 1.25.gamma./ml of p-aminosalicylic acid used as control. Hexaris-O-(p-aminoslicylyl)-muco-inositol showed the strongest antibacterial action at 0.625.gamma./ml, the other compounds more or less active than p-aminosalicylic acid.

• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.196-203
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• 1993

We compared in vitro antibacterial activity of DWC-751, a new parenteral cephalosporin antibiotic, with those of cefpirome (CPR), cefotaxime (CTX) and ceftazidime (CAZ). DWC-751 showed a broad antimicrobial spectrum against Gram-positive and negative bacteria. The antibacterial activity of DWC-751 against Stapylococcus aureus was equal to that of CPR and superior to those of CTX and CAZ. The activity of it against Excherichia coli was more potent than those of CPR, CTX and CAZ. Against Pseudomonas aeruginosa, DWC-751 was slightly inferior to that of CAZ and superior to those of CPR and CTX. The antibacterial activity of DWC-751 was superior to those of CPR, CTX and CAZ against clinical isolates and ofloxacin resistant strains. DWC-751 showed bactericidal action against Escherichia coli at concentrations close to the MIC and induced the formation of filament and burge and lysis of Escherichia coli in a microscopic examination.

• The Korea Journal of Herbology
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• v.30 no.5
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• pp.15-21
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• 2015

Objectives : Methicillin-resistantStaphylococcus aureus(MRSA) is a human pathogen. New antibacterial agents are needed to treat MRSA-related infections. This study investigated the antibacterial activity of EtOH 70% extracts ofTonghyeonipal-dan(THD) which prescription is composed of oriental medicine against MRSA.Methods : The antibacterial activity of THD was evaluated against MRSA strains by using the Disc diffusion method, broth microdilution method, Checkerboard dilution test, and Time-kill test; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors were used.Results : The minimum inhibitory concentration (MIC) of THD is 1,000~2,000 μg/mL against MRSA. In the checkerboard dilution test, fractional inhibitory concentration index (FICI) of THD in combination with antibiotics indicated synergy or partial synergism againstS. aureus. Furthermore, a time-kill assay showed that the growth of the tasted bacteria was considerably inhibited after 24 h of treatment with the combination of THD with selected antibiotics. For measurement of cell membrane permeability, THD 500 μg/mL along with concentration of Triton X-100 (TX) and Tris-(hydroxymethyl) aminomethane (TRIS) were used. In the other hand, N,N-dicyclohexylcarbodimide (DCCD) and Sodium azide (NaN3) were used as an inhibitor of ATPase. TX, TRIS, DCCD and NaN3 cooperation againstS. aureusshowed synergistic action.Conclusions : Accordingly, antimicrobial activity of THD was affected by cell membrane and inhibitor of ATPase were assessed. These results suggest that THD has antibacterial activity, and that THD extract offers great potential as a natural antibiotic against MRSA.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.1
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• pp.31-45
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• 2020

Objectives In this study, we investigated the antimicrobial activity of a 70% ethanol extract of Maneung-hwan (MEH), which is prescribed by practitioners of oriental medicine for use against methicillin-resistant Staphylococcus aureus (MRSA). Methods The antibacterial activity of MEH against MRSA strains was evaluated using the disc diffusion method, broth microdilution method (minimal inhibitory concentration, MIC), checkerboard dilution test, and time-kill test. The mechanism of action of MEH was investigated by bacteriolysis using detergents or ATPase inhibitors Additionally, mRNA and protein expression were investigated by quantitative reverse transcription-polymerase chain reaction and western blot assay, respectively. Results The MIC of MEH was 25~1,600 ㎍/mL against all the tested bacterial strains. We showed that MEH extract exerts strong antibacterial activity. In the checkerboard dilution test, the fractional inhibitory concentration index of MEH in combination with antibiotics indicated synergism or partial synergism against S. aureus. The time-kill study indicated that the growth of the tested bacteria was considerably inhibited after a 24-h treatment with MEH and selected antibiotics. To measure the cell membrane permeability, MEH (3.9 ㎍/mL) was combined with Triton X-100 (TX) at various concentrations N,N-dicyclohexylcarbodimide (DCCD) was also tested as an ATPase inhibitor. TX and DCCD cooperation against S. aureus exhibited synergistic action. Accordingly, the antimicrobial activity of MEH in the context of cell membrane rupture and ATPase inhibition was assessed. Additionally, the expression of genes and proteins associated with resistance was reduced after exposing MRSA to MEH. Conclusions These results suggest that MEH possesses antibacterial activity and acts as a potential natural antibiotic against MRSA.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.1
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• pp.37-40
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• 2003

The antibacterial action of violet pigment, a mixture of violacein and deoxyviolacein, isolated from phychrotrophic bacterium RT102 strain was examined, and the operational conditions for the effective production of violet pigment were studied. The antibacterial activity of the violet pigment was confirmed for several bacteria such as Bacillus licheniformis, Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, and Pseudomonas aeruginosa, and the high concentration of violet pigment, above about 15mg/L, caused not only growth inhibition but also death of cells. The growth properties of RT102 strain were clarified under various incubation conditions such as pH, temperature, and dissolved oxygen concentration. The maximum violet pigment concentration, i.e. 3.7 g/L, and the maximum productivity of violet pigment, i.e. 0.12 g .L$\^$-1/H$\^$-1/, were obtained in a batch culture of pH 6, 20$^{\circ}C$, and 1 mg/L of dissolved oxygen concentration.

• Archives of Pharmacal Research
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• v.21 no.5
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• pp.610-614
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• 1998

DW-116, [1-(5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1-piperazinyl)-1,4-dihydro-4-oxoquino-line-3-carboxylic acid hydrochloride}, is a new quinolone antibiotic with a broad antibacterial spectrum against G(+) and G(-) bacteria. DW-116 was evaluated for the immunomodulating activities, which is one of the efforts to investigate the mechanism of action related to the good in vivo antibacterial efficacy. The results of in vitro studies revealed there was no statistically significant increase in B and T lymphocyte proliferation. But the results of in vivo studies showed that the number of plaque forming cells (PFC), the amount of polyclonal antibodies and delayed-type hypersensitivity (DTH) were significantly increased after the repeat administration with 12 and 60 mg/kg of DW-116. Taken together, these results proposed that immunostimulting effect of DW-116 could be one of the action mechanisms for demonstrating in vivo antibacterial activities under these experimental conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.94-99
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• 1999

This study was carried out to determine the inhibitory effect of juice of garlic, onion, ginger and red pepper against Staphylococcus aureus, Salmonella enteritidis, Vibrio parahaemolyticus and Enterobacter cloacae which are food born disease organisms. It was found that 1~2.5%(wt/vol.) garlic juice showed strong antimicrobial action against growth of all test bacteria at 1/20$\times$10-6 dilution. Especially 1% garlic juice completly inactivated Vibrio parahaemolyticus but approximately 71.9~88% of reduction at same concentration in other bacteria was occurred. 2.5% onion juice had 28.5% antimicrobial activity on Sal. enteritidis, but 50% reduction was occurred on St.aureus and V. parahaemolyticus at same concentration. Antibacterial activity of ginger juice was similar to that of onion juice. 2.5% ginger juice showed approximately 50% reduction on Sal. enteritidis and V.parahaemolyticus, but less antimicrobial activity was occured on St. aureus and E. cloacae. Red pepper juice showed the least antimicrobial activity on food born disease organism compared to that of other juices. 2.5% red pepper juice showed 11.3%, 18.7% and 8.1% reduction on St. aureus, Sal. enteritidis and V.parahaemolyticus, respectively.

• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.225-236
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• 2013

Among several bacteria examined, an antibacterial-producing Lactobacillus strain with probiotic characteristics was selected and identified based on 16S rRNA gene sequencing. Subsequent purification and mode of action of the antibacterial compounds on target cells including E. coli were investigated. Maximum production of the antibacterial compound was recorded at 18 h incubation at $30^{\circ}C$. Interestingly, antibacterial activity remained unchanged after heating at $121^{\circ}C$ for 45 min, 24 h storage in temperature range of $70^{\circ}C$ to room temperature, and 15 min exposure to UV light, and it was stable in the pH of range 2-10. The active compounds were inactivated by proteolytic enzymes, indicating their proteinaceous nature, and, therefore, referred to as bacteriocin-like inhibitory substances. Isolation and partial purification of the effective agent was done by performing ammonium sulfate precipitation and gel filtration chromatography. The molecular mass of the GFC-purified active compound (~3 kDa) was determined by Tris-Tricine SDS-PAGE. To predict the mechanisms of action, transmission electron microscopy (TEM) analysis of ultrathin sections of E. coli before and after antibacterial treatment was carried out. TEM analysis of antibacterial compounds-treated E. coli demonstrated that the completely altered bacteria appear much darker compared with the less altered bacteria, suggesting a change in the cytoplasmic composition. There were also some membrane-bound convoluted structures visible within the completely altered bacteria, which could be attributed to the response of the E. coli to the treatment with the antibacterial compound. According to the in vivo experiments oral administration of L. plantarum HKN01 resulted in recovery of infected BALB/c mice with Salmonella enterica ser. Typhimurium.

• Journal of Environmental Health Sciences
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• v.22 no.2
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• pp.19-24
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• 1996

Carbamates are generally used as insecticide, thus 5.7-dichloro-8~hydroxyquinolinyl- N-ethylcarbamate was newly synthesized. Its physical properties were determined and chemical structure was identified by means of I.R., nmr in addition to elemental analysis. The yield of addition, using triethylamine as catalyst, 5.7-dichloro-8-hydroxyquinoline and isocyanate was better than that of condensation of 5.7-dichloro-8-hydroxyquinoline with carbamoylchloride. The effct of the compound on rabbit's ileum, and antibacterial activity against Staphylococcus aureus, Salmonella typhi, Echerichia coli, and Pseudomonas aeruginosa were examined. The present organic synthesized compound showed the bacteriostatic action on salmonella typhi, escherichia coli, and pseudomonas aeruginosa, but no otherwise effect of contraction of rabbit's ileum in the concentration of $250 \mu g/ml$.