• 약학회지
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• 제34권4호
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• pp.277-281
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• 1990

The isolation and identification of an antibacterial component, from Polygoni Radix against a cariogenic bacterium Streptococcus mutans OMZ 176, were carried out for development of anticariogenic agents. The bioactive component was identified to be emodin. The minimal inhibitory concentration (MIC) of emodin was $100\;{\mu}g/ml$ against S. mutans OMZ 176. The bioactive component emodin weakly inhibited ${\beta}-lactamase$ activity with the inhibition ratio of 1.7, 4.3 and 7.6% at the concentration of 50, 100, and 200 uM, respectively. Emodin exhibited slight phototoxicity when analysed by the photohemolysis method.

• Preventive Nutrition and Food Science
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• 제7권2호
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• pp.215-218
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• 2002

A methanol extract of Physalis angulata exhibited in vitro antibarterial activity against oral pathogens such including Streptococcus mutans and Porphyromonas gingivalis. The methanol extract of Physalis angulata was further fractionated with ethyl acetate, n-butanol and water, in which the ethyl acetate fraction exclusively showed antibacterial activity. An active antibacterial compound from the ethyl acetate fraction was purified to a single compound using silica gel column chromatography and identified as oleanolic acid by $^{13}$ C-NMR, $^1$H-NMR and EI-MS. MIC of oleanolic acid against S. mutants and p. gingivalis were determined to be 50 and 25 ug/mL, respectively. The Antibacterial activity of oleanolic acid from Physalis angulata suggested that it has potential as an anticarcinogenic and antiperiodontic ingredients in various foods and oral care products.

• 대한수의학회지
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• 제37권3호
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• pp.577-582
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• 1997

To investigate the prevalence of Streptococcus suis in pig industry in Korea, we isolated S suis from pigs during two years. The isolates were identified by biochemical and coagglutination test. Serotypes and antimicrobial susceptibility of the isolates were determined. Fourteen strains(12.2%), 11 strains(27.5%), 58 strains(7.8%) and 4 strains(11.1%) of S suis were isolated from 115 nasal swabs, 40 tonsils of healthy pigs, 745 pneumonic lungs and 36 meningitis of diseased pigs, respectively. The isolates were highly susceptible to ampicillin, cephlothin and ofloxacin while they were resistant to oxytetracycline. Among the isolates, 63(75.9%) strains were to the S suis capsular type 1 to 10 and 11(13.3%) strains were untypable. Capsular type 2 was the most prevalent with 32(38.6%) strains of all isolates.

• 대한수의학회지
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• 제56권2호
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• pp.109-111
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• 2016

The present study was conducted to determine the antibiotic susceptibilities of local Mycoplasma hyopneumoniae (Mhp) and Mycoplasma hyorhinis (Mhr) filed isolates. Minimum inhibitory concentrations (MICs) of Mhp and Mhr field isolates (twelve each) obtained from enzootic pneumonia-like lung lesions during 2009-2011 from Korea were determined using the broth microdilution method. Tylvalosin showed the highest activity against Mhp and Mhr field isolates, with $MIC_{90}$ values of $0.06{\mu}g/mL$ and $0.12{\mu}g/mL$, respectively. Therefore, Korean Mhp and Mhr isolates are highly susceptible to tylvalosin.

• Food Science and Biotechnology
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• 제16권6호
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• pp.1051-1054
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• 2007

An edible wild perennial plant with extremely potent antimicrobial activity was found and identified as apiifolia Virgin's Bower (Clematis apiifolia DC) which is easily found around wet wildernesses. Fresh fruit extract of C. apiifolia exhibited minimum inhibitory concentrations (MIC) in the vicinity of 0.1% against various yeasts and of less than or equal to 0.4% for non-lactic acid bacteria. MICs against lactic acid bacteria were about 2.0%. The antimicrobial activity of C. apiifolia fruit was even more potent than that of garlic which has been known for its potent antimicrobial activity. The principal antimicrobial compound of fruit extract of C. apiifolia was isolated and identified by high performance liquid chromatography and gas chromatography as protoanemonin (a gamma lactone of 4-hydroxy-2,4-pentadienoic acid). The antimicrobial activity of C. apiifolia was stable at high temperatures, and the activity was maintained after heating at $121^{\circ}C$ for 10 min. The antimicrobial compound of C. apiifolia was supposed to inhibit microorganisms by reacting with sulfhydryl groups of cellular proteins.

• Mycobiology
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• 제28권1호
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• pp.33-38
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• 2000

Mycelium of Hericium erinaceum isolate KU-1 was cultured in liquid medium (HL medium) and solid medium (Ko medium) at pH 4.0 in $28^{\circ}C$. 1.0% glucose or fructose was the most favorable carbon source, and 0.2% amonium acetate or $NaNO_3$ was an exellent nitrogen source for mycelial growth as well as production of antimicrobial substances. The mixture of saw dust 70% with rice bran 30% (SR medium) was the substrate for formation of sporophores. The active substrates in extracts from mycelium, culture filtrate and fruiting body were separated by TLC. The solvent for TLC was EtOAc: Chloroform: MeOH (10 : 5 : 10). Phenol-like substances appeared at Rf $0.5{\sim}0.9$, and fatty acid-like substances appeared at Rf $0.1{\sim}0.2$. The purified materials from the extracts showed antimicrobial effects to Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Aspergillus niger, Candida albicans and Microsporum gypseum. The S. aureus was the most inhibited. Minimal inhibitory concentration (MIC) of purified white powder and the Hercenone derivatives against S. aureus were $5.65\;{\mu}g/ml$ and $1.85\;{\mu}g/ml$, respectively.

• Archives of Pharmacal Research
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• 제26권10호
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• pp.778-784
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• 2003

N'-(1-alkyl-2,3-dihydro-2-oxo-1H-3-indolyliden)-4-pyridinecarboxylic acid hydrazide derivatives, 3(a-g), were synthesized in a trial to overcome the resistance developed with the therapeutic uses of isoniazid (INH). The lipophilicity of the synthesized derivatives supersedes that of the INH as expressed by Clog p values. The synthesized compounds and INH were tested against bovin, human sensitive and human resist strains of Mycobacterium tuberculosis. Compounds 3a, 3d, 3f and 3g with 1-unsubstituted, 1-propyl, 1-propynyl and 1-benzyl groups respectively exhibited equipotent growth inhibitory activity (MIC 10 $\mu$mol) against the tested strains as compared with INH however the later has no activity against human resist strain. Pharmacokinetic study revealed that the rate and extent of absorption of the tested derivatives (3d and 3f) significantly higher than that of INH (p＜0.05). The relative bioavailabilities ($F_R%$) were 183.15 and 443.25 for 3f and 3d respectively as compared to INH. These results preliminary indicate the possible use of the prepared derivatives for treatment of tuberculosis infections in order to overcome the resistance developed with INH.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.149-150
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• 2006

In this paper, design, simulation, fabrication method, and measured results of a digital frequency discriminator(DFD) operating in E, F, and G band are introduced. We describe the direct conversion scheme(DCS) with microwave integrated-circuit(MIC) developed for the small-area and high-speed system. When the input signal is the pulse with a pulse width of 100 ns, accuracy of frequencies measured by the DFD has 1.335 MHz RMS at no noise and 2.64 MHz RMS at signal-to-noise(S/N) ratio within 3 dB in E, F, and G band, which nearly satisfy the specification of 2.5 MHz RMS.

• Archives of Pharmacal Research
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• 제20권3호
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• pp.275-279
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• 1997

Helicobacter pylori (H. pylorl) infection is now established as the major pathogenic factor in chronic gastritis and peptic ulcer disease. in addition, there is accumulating evidence that H. pylori plays an important role in the process of gastric carcinogenesis. On the other hand, oriental traditional medicines have been used for stomach disease for thousands of years. In the present study, methanol extract from the stem bark of Magnolia sieboldii (M. sieboldii) and its components were investigated on their inhibitory effects against urease activity and growth of H. pylori in vitro. The methanol extract of M. sieboldii significantly inhibited the growth of H. pylori ATCC 43504 at 5 mg/ml. From the further fractionation, the chloroform fraction inhibited the bacterial growth dose-dependently. Among four fractions separated from the chloroform fraction by silica gel column chromatography, MS-C-2 was the most potent. Costunolide was isolated from the MS-C-2 subtraction by preparative TLC and recrystallization using n-hexane. Anti-H. pylori effect of costunolide was investigated using one commercial strain (H. pylori ATCC 43504) and three clinical strains (H. pylon 4, 43, 82548). Costunolide exhibited potent anti-H. pylori activity, and the MIC was around $100-200{\mu}g/ml$. However, costunolide had no inhibitory effect of H. pylori urease activity at the concentration used for the growth inhibition assay. From these results, we conclude that costunolide inhibits the, growth of H. pylori by the independent manner of H. pylori urease inhibition.

• International Journal of Oral Biology
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• 제38권2호
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• pp.51-54
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• 2013

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causative microbes for nosocomial infection and has been isolated from the dental environment. The purpose of this study was to investigate the antimicrobial activity of linalool and ${\alpha}$-terpineol against MRSA isolates from a Korean population. In the experiments, we determined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these two compounds against 18 strains of MRSA. The data revealed that the $MIC_{90}/MBC_{90}$ values of linalool and ${\alpha}$-terpineol against MRSA were >12.8 mg/ml and 6.4 mg/ml, respectively. These results indicate that ${\alpha}$-terpineol has more potent antimicrobial activity against MRSA than linalool and may have utility as an anti-MRSA cleansing agent for dental instruments and dental unit chairs.