• KSBB Journal
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• v.30 no.2
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• pp.69-76
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• 2015

The antibacterial activity of a antimicrobial (organic synthetic or organic natural material) on the bacteria (Bacillus megaterium, Arthrobacter oxydans, Micrococcus luteus, Methylobacterium aquaticum) detected in the automobiles showed 99.9% bacteria decrease rate within 30 min of being in contact with the tested bacteria culture. The MIC of the organic synthetic material based antimicrobials and the organic natural material based antimicrobial on the bacteria were 31~500 mg/mL and 8~250 mg/mL, respectively. The bacteria and biofilms were formed on the surface of aluminum after 5 ~8 days in the case of addition of the organic synthetic material based antimicrobial to the MIC values for the tested bacteria culture. On the other hand, there was no proliferation of bacteria and formation of biofilms on the surface of aluminum even after 30 days in the case of addition of the organic natural material based antimicrobial to the MIC values for the tested bacteria culture. As a result, the organic natural material based antimicrobial was confirmed to be more excellent effect of inhibition of bacterial proliferation and restraint of biofilms formation than the organic synthetic material based antimicrobial.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8883-8886
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• 2014

Background: Tetracycline is an antibiotic widely used for the treatment of Helicobacter pylori infection, but its effectiveness is decreasing due to increasing bacterial resistance. The aim of this study was to investigate the occurrence of 16S rRNA mutations associated with resistance or reduced susceptibility to tetracycline ofHelicobacter pylori by real-time PCR (RT-PCR) assays from culture. Materials and Methods: Tetracycline susceptibility and minimal inhibition concentration (MIC) was determined by the Epsilometer test (Etest) method. A LightCycler assay developed to detect these mutations was applied to DNA extracted from culture. The 16S rRNA of these isolates was sequenced and resistance-associated mutations were identified. From 104 isolates of H. pylori examined, 11 showed resistance to tetracycline. Results: LightCycler assay was applied to DNA extracted from 11 tetracycline-susceptible and 11 tetracycline resistance H. pylori isolates. In our study the sequencing of the H. pylori wild types in 16 s rRNA gene were AGA 926-928 with MIC (0.016 to $0.5{\mu}g/ml$), while the sequencing and MIC for resistant were GGA and AGC, (0.75 to $1.5{\mu}g/ml$), respectively. Also we found a novel mutation in 2 strains with $84^{\circ}C$ as their melting temperatures and exhibition of an A939C mutation. Conclusions: We conclude that real-time PCR is an excellent method for determination of H. pylori tetracycline resistance related mutations that could be used directly on biopsy specimens.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.243-249
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• 2001

This study was investigated to determine the antimicrobial effect of the ethanol extract of Quercus mongolica leaf on microbial growth. The ethanol extract at the concentration of $250\;\mu\textrm{g}/mL\;and\;500\;\mu\textrm{g}/mL$ inhibited the growth of gram positive and gram negative food-borne disease bacteria for 40 hours in tryptic soy broth, respectively. Antimicrobial activity of the ethanol extract from Quercus mongolica leaf was not affected by pH and heat treatment. The comparision between ethanol extract and commercially available preservatives on antimicrobial activity in food system was conducted. When the 0.1% ethanol extract of Quercus mongolica leaf was added to pine needle drink and carrot juice, antimicrobial activity was similar to those of containing 0.05% benzoic acid and 0.5% grapefruit seed extract. Also addition of 2~3% ethanol extract to the soybean paste inhibited the microbial growth up to 7 week, comparable to the inhibition of 2% ethanol. Thus, this results indicate that the ethanol extract of Quercus mongolica leaf may be useful as natural antimicrobial agents.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.690-695
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• 2005

The purpose of this thesis is to dedicate to get the objectivity of herbal medicine treatments by choosing herbs likely to work as antifungal agents against Candida albicans which is the causes of Candida vaginitis, making experiments on them and getting the significant results. Each herb's efficacy on control the number of Candida vaginitis is noticed by using Disk Susceptibility test with six herbs medicine and Broth dilution assay of the culture. Cinamon Ramulus, Pulsatillae Radix, Dictamni Radicis Cortex, Paeoniae Radix, Arecae Semen, Artemisiae Capillaries Herba extracts experimented on the efficiency of antifungal activities against Candida albicans by disk susceptibility test. Pulsatillae Radix has the strongest efficiency. In Dictamni Radicis Cortex never appeared antifungal effect on treatment. MIC (minimal inhibition concentration) in vitro antifungal agents of Cinamon Ramulus, Pulsatillae Radix, Paeoniae Radix, Artemisiae Capillaries Herba extracts against Candida albicans was determined by broth dilution assay. MIC against Candida albicans is that Pulsatillae Radix is 2.5 mg/ml and Cinamon Ramulus is 5 mg/ml and Paeoniae Radix is 10 mg/ml and Artemisiae Capillaries Herba is 40 mg/ml.

• Korean Journal of Microbiology
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• v.33 no.3
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• pp.170-174
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• 1997

In order to design a novel synthetic peptide with improved fungicidal activity but low hemolytic activity, a hybrid peptide, cecropin A(l-8)-magainin 2(1-12), and its analogue peptides were synthesized by the solid phase method. Antifungal and hemolytic activities of the synthetic peptides were assessed by the growth inhibition against Trichosporon beigelii and the cell membrane lysis against human red hlood cells, respectively. Analogue 2 in which Lys at position 12 in cecropin A(1-8)-magainin 2(1-12) was substituted with Ala showed most potent antifungal activity (MIC: 2.5.$\mu$g/ml) with minimal hemolytic activity (0.5% hemolysis at the (200.$\mu$g/ml peptide). This peptide (A2), therefore, could be useful as a model for further designing potent antifungal peptides without cytotoxicity.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.161-165
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• 2003

Ornithobacterium rhinotracheale (OR) is a recently described gram-negative rod-shaped bacterium associated with respiratory tract infection in poultry. In order to investigate current occurrence of OR infection and to evaluate antibiotic susceptibility, the prevalence of OR antibody in domestic chickens were examined and the minimal inhibitory concentrations(MICs) of 8 antibiotics for 11 OR isolates was determined. All isolates tested were mostly susceptible to three antibiotics, ampicillin (MICs ranging from 0.38 ${\mu}g$/ml to 2 ${\mu}g$/ml), tetracycline (MICs 0.094～3 ${\mu}g$/ml) and doxycycline (MICs 0.047～4 ${\mu}g$/ml) but resistant to genatmicin. Ciprofloxacin, norfloxacin, enrofloxacin, and ofloxacin gave most isolates inhibition only in case of a higher concentration (MICs ranged in most cases from 3 ${\mu}g$/ml to 48 ${\mu}g$/ml). Out of 188 chicken flocks including broilers, broiler breeders, and layers, seropositive flock to OR were detected in 5 broilers (4%), 17 broiler breeders (50%), and 16 layers (55.2%), using commercial OR enzyme-linked immunosorbent assay(ELISA) kits. It suggested that OR infection was widespreaded in poultry farms in Korea.

• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.249-257
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• 2020

This study investigated whether the extracts from cosmos flowers exhibit antibacterial activities and identified which components were ascribed to the antibacterial effects. The antibacterial effects of extracts from white, pink, and violet cosmos flowers were observed for 24 h after inoculation with four kinds of bacteria, including Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. Among the three fractions of cosmos flower extracts, the best antibacterial activity against the four bacteria was observed in the extracts isolated from the EtOAc layer. However, the extracts from the CHCl₃ layer were also effective against S. aureus. Moreover, the first of white, second of pink, and first of violet silica gel fractions (Fr.) isolated from the EtOAc layer exhibited minimal inhibition at a concentration of 0.1 mg/mL. Comparison of NMR and High-Pressure Liquid Chromatography results between silica gel Fr. and apigenin suggested that the effective fractions can contain a component including apigenin moiety.

• Journal of Ginseng Research
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• v.38 no.3
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• pp.208-214
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• 2014

Background: In previous work, we reported that Korean Red Ginseng saponin fraction (RGSF) showed anti-inflammatory activities in vitro and in vivo. Methods: The present study investigated the radioprotective properties of RGSF by examining its effects on ionizing radiation (IR)-enhanced and lipopolysaccharide (LPS)-mediated inflammatory responses in murine macrophage cells. Results: RGSF induced strong downregulation of IR-enhanced and LPS-induced proinflammatory responses such as nitric oxide (NO) production (Inhibitory Concentration $50(IC_{50})=5.1{\pm}0.8{\mu}M$) and interleukin-$1{\beta}$ levels. RGSF was found to exert its radioprotective effects by inhibition of a signaling cascade that activated checkpoint kinase 2enuclear factor-${\kappa}B$. In addition, RGSF strongly inhibited IR-enhanced LPS-induced expression of hemoxyganase-1, implying that the latter may be a potential target of RGSF. Conclusion: Taken together, our data suggest that RGSF can be considered and developed for use as an effective radioprotective agent with minimal adverse effects.

• YAKHAK HOEJI
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• v.40 no.3
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• pp.351-356
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• 1996

The preparation of Enterococcus faecalis RSI is used as a therapeutics for human intestinal disorders. However, the microbe in this preparation is usually very sensitive to rifampicin and fluoroquinolones. If this preparation is taken with rifampicin or fluoroquinolones, its therapeutic effect can not be expected. E. faecalis RFR11, containing resistance to rifampicin was obtained by MNNG mutation method. Serial passage of E. faecalis RFR11 produced E. feacalis OFR16 on agar with 2-fold minimal inhibitory concentration of ofloxacin produced. E. feacalis OFR16 was resistant to fluoroquinolones up to 8-256 fold higher than that for the original strain. E. faecalis OFR16 also exhibited identical characteristics with the parent strain when they were tested for lactic acid formation and growth inhibition of E. coli MB4-5737 and Shigella sonnei MB4-10411. From in vitro test, it was identified that rifampicin and ofloxacin is not inactivated by certain factors of E. faecalis OFR16. Conclusively. E. faecalis OFR16, rifampicin and fluoroquinolones resistant mutant, is an efficient strain that has insensitivity against rifampicin and fluoroquinolones and original biochemical characteristics of the parent strain.

• Archives of Pharmacal Research
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• v.29 no.6
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• pp.490-496
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• 2006

This study aimed to evaluate in vitro effects of Rheum undulatum L. root on the development of dental caries, especially its effects on viability, dental plaque formation, and glycolytic acid production of Streptococcus mutans and Streptococcus sobrinus. Methanol extract of Rheum undulatum L. root and its fractions were prepared and tested. Among the test extract and fractions, dichloromethane fraction (DF) showed the most active antibacterial activity (inhibition zone: 13-17 mm) against S. mutans and S. sobrinus in a disc diffusion method. Minimal inhibitory concentrations (MICs) of DF against these bacteria ranged from 0.25 to 0.5 mg/mL. Furthermore, DF significantly inhibited the caries-inducing factors of these bacteria. At sub-MIC levels, DF inhibited in vitro dental plaque formation by S. mutans and S. sobrinus ($IC_{50}$= 0.079 and 0.142 mg/mL, respectively), which was caused, in part, by the inhibitory effect on the activity of glucosyltransferases. A significant reduction of glycolytic acid production was found at the concentration as low as 0.032 mg/mL for S. mutans and 0.063 mg/mL for S. sobrinus. The possible bioactive compounds that are inducing in vitro anti-cariogenic activity of DF are unknown. Based on the preliminary phytochemical analysis, the activity of DF may be related to the presence of anthraquinones, cardiac glycosides, coumarines, sterols/terpenes, and phenolics. These results indicate that DF is probably useful for the control of dental plaque formation and subsequent dental caries development.