• 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.

• Journal of Applied Biological Chemistry
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• v.50 no.3
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• pp.148-154
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• 2007

Volatile components of the essential oils of Satsuma mandarin (C. unshiu), Dangyuza (C. grandis), Yuza (C. junos), Byungkyul (C. playtymamma), Jinkyul (C. sunki), and Hakyul (C. natsudaidai) grown in Jeju Island were isolated from the fruit peels by hydro distillation and determined by GC-MS. GC-MS analysis identified 58 compounds, with main components being d-limonene $(64.01{\sim}79.34%),\;{\beta}-myrcene\;(3.01{\sim}26.53%),\;{\gamma}-terpinene\;(0.11{\sim}12.88%),\;{\beta}-pinene\;(0.78{\sim}4.74%),\;and\;{\alpha}-pinene\;(1.01{\sim}2.55%)$. Differences in compositions and contents of the essential oils were observed among citrus varieties. Effects of citrus oils on growth inhibitions of Escherchia coli, Staphyllococcus epidermidis, and Candida albicans were investigated using disc diffusion assay and minimal inhibitory concentration (MIC) assay. The essential oils inhibited growths of the test organisms, exhibiting higher levels of activity against Gram-positive S. epidermidis (MIC values $0.04{\sim}0.17mg/mL$), whereas Gram-negative E. coli was moderately resistant (MIC values $1.66{\sim}20.30mg/mL$). MIC of citrus essential oils ranged from $0.82{\sim}23.69mg/mL$ against C. albicans. The essential oils obtained from C. sunki, C. grandis, and C. playtymamma showed the highest antimicrobial activities against S. epidermidis and C. albicans, indicating their potential as natural antimicrobial agents.

• 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 the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.293-298
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• 1995

Antimicrobial effect of tea extracts from green tea(steamed, roasted), oolong tea and black tea was investigated. Minimal inhibitory concentration(MIC) of tea extraxcts against 9 well known strains of foodborne pathogenic bacteria such as the Gram positive and Gram negative bacteria was determined at 37$^{\circ}C$. Significant antimicrobial activity was observed in the steamed green tea and the roasted green tea of the water-soluble fraciton, and the steamed green tea of the methanol-soluble fraction, and the steamed green tea, roasted green tea and the oolong tea of the crude catechin fraction. The MIC of these extracts against B. subtillis were 700$\mu\textrm{g}$/ml, 500$\mu\textrm{g}$/ml and 120 $\mu\textrm{g}$/ml, respectively. The crude catechin fraction possessed greater antimicrobial activity than did the other fractions. Among tea extracts, extracts of steamed green tea, roasted green tea and oolong tea showed higher antimicrobial activity than them of black tea. The MIC of the crude catechin fraction obtained from tea extracts against Gram-positive bacteria such as M. Iuteus, B. subtillis and S. mutans were 30~50$\mu\textrm{g}$/ml, 120~240$\mu\textrm{g}$/ml and 120~180$\mu\textrm{g}$/ml, and against Gram-negative bacteri such as e. aerogenes and V. parahaemolyticus were 50~60$\mu\textrm{g}$/ml and 60~70$\mu\textrm{g}$/ml in the broth medium, respectively. Especially, the MIC to Streptococcus mutans which has known as a causative bacteria of a decayed tooth were 120$\mu\textrm{g}$/ml, 140$\mu\textrm{g}$/ml, 180$\mu\textrm{g}$/ml and above 1,000$\mu\textrm{g}$/ml in steamed green tea, roasted green tea, oolong tea and black tea, respectively. Tea extracts had strong growth inhibition activity against foodborne pathogenic and dental bacteria.

• Archives of Pharmacal Research
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• v.15 no.3
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• pp.220-223
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• 1992

The methanolic extract of Commelina communis (aerial part) showed antibacterial activity against a cariogenic bacterium, Streptococcus mutans OMZ 176. The active principles were identified to be $\beta$-carboline alkaloids, 1-carbomethoxy-$\beta$-carboline, norharman and harman, which were bactericidal in the minimal inhibitory concentration (MIC) of $100\;\mu{g/ml}$ against the strain.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.338-343
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• 2001

The ethanol extract of Quercus mongolica leaf was fractionated by various organic solvents, and their antimicrobial and antioxidative activities were investigated against several microorganisms. The ethanol extract of Quercus mongolica leaf at two thousand $\mu\textrm{g}$ per disc showed 17~21mm inhibition zone against Gram postive and Gram negative bacteria. Among the various solvent fractions from ethanol extract of Quercus mongolica leaf, the hexane fraction showed the strongest antimicrobial activity. Minimal inhibitory concentration (MIC) of hexane fraction was 250$\mu\textrm{g}$/mL against Bacillus cereus, 250~500$\mu\textrm{g}$/mL against Listeria monocytogenes, 500$\mu\textrm{g}$/mL against Staphylococcus aureus, Salmonella typhimurium, Escherichia coli O157, and Pseudomonas aeruginosa. Also, the hexane and chloroform fraction had the similar antioxidative activity compared to that of butylated hydroxy toluene(BHT).

• Korean Journal of Pharmacognosy
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• v.28 no.3
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• pp.99-103
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• 1997

To develop anticariogenic agents, Scutellariae Radix was tested for its antibacterial activity against Streptococcus mutans OMZ176 which is known as a strong cariogenic bacterium. The antibacterial activity was evaluated with disk plate method and minimal inhibitory concentration (MIC). The ethyl acetate fraction showed significant activity. By means of activity-guided fractionation, baicalein and ganhuangenin were isolated as the active principles. The MICs of these compounds were $100{\mu}g/ml$ and $200{\mu}g/ml$, respectively.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.4
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• pp.635-640
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• 2011

Betulae Cortex of Betula platyphylla Suk. var. japonica Hara (Betulaceae) has long been used for treatment of various inflammation, fever and cough in Eastern Asia. In order to investigate antibacterial activity of the Betulae Cortex against Streptococcus mutans or Porphyromonas gingivalis, MIC (minimal inhibitory concentration) and pH were checked, and for anti-inflammation activity, the experiments about trypsin-induced paw edema, vascular permeability and myeloperoxidase activity in rat's hind-paw tissue, were carried out with various extracts of Betulae Cortex (BCXs) respectively. The BCXs showed significant antibacterial activity, and at the dose of over 50 mg/kg, BCX showed significant inhibition on the paw edema, vascular permeability and myeloperoxidase activity. These results indicate that BCXs have antibacterial activity against oral cariogenic bacteria and anti-inflammatory effect.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.143-143
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• 1993

현재 시판되고 있는 정장용 생균 제제에 함유되어있는 정장 균주의 하나인 Bifidobacterium bifidum은 항결핵제 중 rifampicin에 감수성으로 rifampicin과 병용 투여시 본래의 정장 효과를 기대할 수없다. 따라서, rifampicin에 내성인 돌연변이 균주를 얻기 위해 B. bifidum을 N-methyl-N'-nitro-N-nitrosoguanidine(MNNG)로 처리하여 rifampicin에 내성인 30 종의 균주를 선별하였고, rifampicin에 대한 Minimal Inhibitory Concentration (MIC)를 측정해 본 결과 내성이 1,000 배 이상 상승하였다. 균주 동정을 위하여 fructose-6-phosphate phosphoketolase test를 실시해 본 결과 Bifidobacterium임이 확인되었다. 이들 내성 균주들의 유기산 생산량을 측정하여 그 생산량이 모균주와 가장 유사한 3 종의 균주를 선발하였다. 이들에 대하여 Escherichia coli 생육 억제능을 시험해 본 결과 E. coil 생육 억제능이 모균주와 유사하였다. 또, rifampicin을 함유한 배지에서 돌연변이 균주를 배양시킨 경우 rifampicin이 안정한 상태로 잔존한 것을 알 수 있었다. 이것으로 보아 돌연변이 균주들은 rifampicin을 분해 또는 변형시키는 효소를 생산하지 않는다고 볼 수 있다. 이상의 결과로 본 연구에서 개발한 돌연변이 균주들, 즉 B. bifidum RFRll, RFR21 그리고 RFR61은 rifampicin에 내성이면서 모균주와 동일한 생화학적 특성을 갖는 정장 균주로 여겨진다.

• Journal of the Korean Wood Science and Technology
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• v.33 no.2 s.130
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• pp.72-77
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• 2005

Streptococcus mutans is known as a strong cariogenic bacterium and produces dental caries. This study was carried out to develop anticariogenic agents from Callistemon citrinus. Crude extracts and thier various solvent fractions of the plant extracts were tested for the antibacterial activity against S. mutans. The anticariogenic activity was evaluated with by paper disc diffusion method and minimal inhibition concentration (MIC). The extract from the fruit and its hexane fraction showed a strong inhibitory effect on the growth of S. mutans and the MICs were 31.2 and $3.9{\mu}g/m{\ell}$, respectively.