• The Korean Journal of Mycology
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• v.16 no.1
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• pp.33-40
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• 1988

To investigate the antimicrobial activities and safety of natural naringin, it was isolated with methanol from peels of Citri fructus. Its hydrolysate, naringenin was obtained by hydrolysis of naringin. In the antimicrobial activities of two components against eleven species of bacteria and eleven species of Fungi were examined by serial dilution method. Its result appeared to the minimal inhibitory concentration(MIC) and the antimicrobial activities of naringin and naringenin were compared. Naringenin showed considerably high order of activities against bacteria. There were no effect against Fungi $(MIC>100{\mu}g/ml)$. In the safety tests of naringin, examined for 50% lethal dose, Blood clinical chemical tests and organ tissue tests. The results showed that 50% lethal does in mice was 1,650 mg/kg. The experiments of administration in rats showed that there were no changes in blood clinical chemical future and organ tissue as control.

• Korean Journal of Pharmacognosy
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• v.31 no.1
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• pp.72-76
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• 2000

This study was carried out to evaluate cytotoxic effects of Ajuga multiflora Bunge extracts on murine leukemia tumor $(P388D_1)$ cell lines. Disruptions in cell organelles were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazoliumbromide (MTT) assay. The comparison of $IC_{50}$ values of Ajuga multiflora Bunge extracts in L1210 and $P388D_1$ cell lines showed that their susceptibility to these extracts decreased in the following order: Adriamycin>methanol extract>chloroform extract>ethyl acetate extract>hexane extract>water extract by the MTT assay. In order to develop an antimicrobial agent, dried Ajuga multiflora Bunge was extracted with several solvents, and then antimicrobial activity was investigated. The minimal inhibitory concentration (MIC) of the extract against microorganisms were also examined. Antimicrobial activities of amocla and ketoconazole as references were compared to those of extracts of $H_2O$, n-hexane, chloroform, ethyl acetate and methanol. The antimicrobial activity of all extracts from the sample had growth inhibition activity against gram-negative bacteria, gram-positive bacteria and fungi $(MIC>200\;{\mu}g/ml)$. These results suggest that the methanol soluble extract of Ajuga multiflora Bunge may be a valuable choice for the studies on the treatment of murine leukemia tumor cell lines.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.380-388
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• 2012

A total of 5 different polar microorganisms were isolated from Arctic lichens and their bioactive compounds were extracted from cell culture using different solvents including acetone, water, chloroform, diethylether, ethanol, ethyl acetate, methanol, and petroleum ether. The antibacterial properties of the extracts were evaluated by disk diffusion tests and minimal inhibitory concentration tests against 6 bacterial pathogens; Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Enterobacter cloacae, Pseudomonas aeruginosa and Escherichia coli. Among the extraction samples, ethyl acetate extracts of Burkholderia sordidicola S5-$B^T$ (KOPRI 26644) showed the highest activity (inhibition zone, 7-10 mm; MIC value, 57.5-1000 ug/ml) against targeted bacteria. Among the various solvents used for extraction, chloroform extract exhibited the weakest, but still obvious, activity.

• Biomedical Science Letters
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• v.5 no.1
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• pp.27-40
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• 1999

This study was focused on the evaluation of MarB alongside with MarA for its regulatory effects upon the efflux function of AcrAB pump, which were induced or not, perhaps as a target. Transductions of marR and/or acrAB mutation which were derived from Mar and/or AcrAB mutants of wild type E. coli K-12, respectively, into the multicopy plasmid in wild type E. coli backgrounds or into the chromosome of isogenic parents were done. Minimal inhibitory concentration (MIC) of transduced mutants was compared with their original mutants. This study reports the indirect evidences that suggests a model in which MarB along with MarA have a putative negative regulatory effect upon the efflux function of AcrAB/TolC pump while MarA alone have a positive regulatory effect to the expression of acrRAB operon at transcription level. The target of MarB with MarA for its putative negative regulator might be the AcrAB efflux pump. Another efflux system (s) might be negatively regulated by MarB with MarA, and be involved in the efflux of antibiotics which were otherwise extruded preferentially by AcrAB efflux pump.

• YAKHAK HOEJI
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• v.43 no.4
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• pp.419-422
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• 1999

In order to develop a antimicrobial agent, dried Sophora flavescens Ait. was extracted with several solvents, and than antimicrobial activity was investigated. The minimal inhibitory concentration (MIC) of the extracted substance against microorganisms were also examined. Antimicrobial activity of the initial methanol extract from the sample was the strongest compared to those of other solvent extracts such as $H_2O$, n-hexane, chloroform, ethyl acetate and methanol. The methanol extract had strong growth inhibition activity against gram-postive bacteria (MIC, $25~50{\;}{\mu\textrm{g}}/ml$) such as B. subtilis. Among gram-positive bacteria tested, B. subtilis was the most susceptible to the extracted substance. The antimicrobial activity of the methanol extract from the sample had strong growth inhibition activity against gram-negative bacteria such as P. aeruginosa (MIC, $25{\;}{\mu\textrm{g}}$/ml).

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.401-411
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• 2005

The aim of this study was to determine the minimal inhibitory concentration(MIC) of cefixime, which is a 3rd generation of cefalosporin, against 6 species of putative periodontopathogens; Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans, Prevotella intermedia, Prevotella nigrescens, Tannerella forsythia and Porphyromonas gingivalis. The efficacy of cefixime was examined by comparing it with that of several antibiotics(amoxicillin, $Augmentin^{(R)}$ ciprofloxacin, metronidazole, and tetracycline), which were used as the control. The MIC was measured using a microdilution method. The MIC of cefixime against the putative periodotopathogens, as a single use regimen, was relatively lower than that of the other antibiotics. The MIC of cefixime/metronidazole against P. intermedia ChDC KB14, P. nigrescens ChDC KB50, F. nucleatum ChDC PV-F37, F. nucleatum ChDC F130, and F. nucleatum ChDC F175, as a simultaneous regimen, was lower than that of the other antibiotics. The concentration of cefixime in the crevicular fluid of volunteers who received 250mg every 12 hours for 3 days was $9{\mu}g/ml$ after 9 hours. In conclusion, cefixime showed good antimicrobial activity in a single treatment or as a combined therapy with amoxicillin, $Augmentin^{(R)}$ or metronidazole against 6 periodontopathogens.

• The Korean Journal of Mycology
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• v.23 no.1 s.72
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• pp.28-36
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• 1995

To investigate the antibacterial activities of 53 species of mushrooms for Gram-positive bacteria, bioactive substances from mushrooms were extracted with petroleum ether, 80% ethanol, and distilled water. The 14 extracts of 12 species of mushrooms, largely with 80% ethanol, showed antibacterial activities against 6 species of Gram-positive bacteria selectively. Especially, the extracts of Thylopilus PS-5, Pulveroboletus PS-7, and Russula PS-9 showed various antibacterial activities against several bacteria. Minimal inhibitory concentration (MIC) of the 80% ethanol extracts from Pulveroboletus PS-7 and Boletus PS-8 was $300\;{\mu}g/ml$ against Bacillus subtilis, and that of the 80% ethanol extracts from Trichaptium PS-3 was $500\;{\mu}g/ml$ against Micrococcus luteus. MIC of other extracts with antibacterial activities was above $1000\;{\mu}g/ml$.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.1-11
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• 2009

Essential oils are mixture of volatile, lipophilic compounds originating from plants. Essential oils have potential biological effects, i.e., antibacterial, antifungal, spasmolytic and antiplasmodial activities and insect-repellent property. In this study, five essential oils, namely R, LG, FR, O, and NM, extracted from various aromatic plants were used to test their antimicrobial activity against the oral microorganisms. The effects of essential oils were investigated against eight important bacteria, Streptococcus mutans (S. mutans), Staphylococcus aureus (S. aureus), Streptococcus sanguis (S. sanguis), Streptococcus anginosus (S. anginosus), Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans), Streptococcus sobrinus (S. sobrinus), Staphylococcus epidermidis (S. epidermidis), and Escherichia coli (E. coli). Essential oils, except NM, effectively inhibited the growth of tested oral pathogenic microorganisms dose-dependently. However, the essential oils didn't show a significant inhibitory effect against E. coli and S. epidermidis. Consequently, these results represented that essential oil-mediated anti-microbial activity was prominent against the oral pathogenic bacteria. For example, minimum bactericidal concentration(MBC) of R, LG, FR oil against A. actinomycetemcomitans was very low as 0.078 mg/mL. In addition, minimum inhibitory concentration (MIC) of R, LG, FR, O oil against S. mutans was low as 0.156 mg/mL in vitro.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.265-265
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• 2002

Iron increased the susceptibilities of clinical isolates Pseudomonas aeruginosa to quinolones. In the presence of iron, increased susceptibilities to ofloxacin were observed in twenty-six out of thirty isolates and with no change in four isolates. In the case of norfloxacin, iran increased susceptibilities of twelve isolates but did not render any change in eighteen isolates. In the case of ciprofloxacin, iron decreased the MICs (Minimal Inhibitory Concentration) of twenty isolates, increased the MIC of one isolate, and did net change the MICs of nine isolates. To find out how iron increased susceptibility to ofloxacin, bacterial cells were grown in Muller Hinton (MH) media and succinate minimal media (SMM) to induce iran acquisition systems and the intracellular ofloxacin concentrations were assayed in the presence of iron. The addition of iron to the media decreased the MICs of cells whether they were grown in MH or SMM. Siderophores, carbonyl cyanide m-chlorophenylhydrazone (an inhibiter of proton motive force), and ouabain (an inhibitor of ATPase) did not decrease the effect of iron. Results suggested that the increase in the intracellular ofloxacin concentration by iron is accomplished not by decreasing the efflux but by increasing the of ofloxacin permeability.

• Archives of Pharmacal Research
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• v.19 no.2
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• pp.143-147
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• 1996

LB20304 is a novel fluoroquinolone that exhibits a potent broad spectrum antibacterial activity against both gram-positve and gram-negative bacteria. The MICs (Minimal Inhibitory Concentration) of LB20304 were determined against both gram-positve and gram-negative bacteria under various conditions including several media, pHs, and inoculum concentrations. The in vitro activity of LB20304 was not significantly affected by the changes in testing conditions such as components of media and inoculum concentrations, but it was slightly reduced by acid condition. The MICs and MBCs (Minimal Bactericidal Concentration) of LB20304 against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were hardly affected by the presence of 50 % human serum, mouse serum, guinea pig serum or horse serum, and the MBCs were equal to or at most four-times higher than the MiCs. The activities of LB20304 were decreased by the presence of high concentraion of $Mg^{++}$ or human urine (pH, 5.5) in the test media. The frequencies of mutants resistant to LB20304 were similar to or lower than those found in ciprofloxacin and sparfloxacin.