• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.678-682
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• 2016

Antibacterial activity of 80% methanol extract from 13 commercial herb medicines was measured against fish pathogens Streptococcus iniae, causing several diseases in various kind of fish. Siegesbeckia pubescens showed the strongest antibacterial activity against S. iniae. Methanol extract of S. pubescens was further extracted using several organic solvents having different polarity. Extract from n-hexane and ethyl acetate fraction showed strong activity. Minimal inhibitory concentration, MIC of S. pubescens extract was measured and resulted showing 8 μg/mL with n-hexane fraction and 32 μg/mL with ethyl acetate fraction against S. iniae. The growth of S. iniae was fully inhibited by adding 50 μg/mL (final concentration) of n-hexane or ethyl acetate fraction in the liquid media. It is needed that, from these results, purification and isolation of responsible active compound(s) of these activities and further study on the synergy effect using combination with commercial antibiotics against fish pathogenic bacteria.

• Journal of Microbiology and Biotechnology
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• v.34 no.8
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• pp.1642-1652
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• 2024

Arctium lappa (Burdock) root is used in various culinary applications especially in Asian Cuisine. Arctigenin (ARC) is a polyphenolic compound abundant in the roots of the burdock plant from which it derives its name. The emergence of bacterial resistance is a growing global worry, specifically due to the declining availability of new antibiotics. Screening for the antibacterial candidates among the safe natural products is a promising approach. The present study was aimed to assess the antibacterial activity of ARC against Pseudomonas aeruginosa exploring its effect on the bacterial cell membrane. Furthermore, the anti-virulence activities and anti-quorum sensing (QS) activities of ARC were in vitro, in vivo and in silico assessed against P. aeruginosa. The current results showed the ARC antibacterial activity was owed to its disruption effect of the cell membrane. ARC at sub-MIC significantly decreased the formation of biofilm, motility, production of extracellular enzymes and in vivo protected mice against P. aeruginosa. These anti-virulence activities of ARC are owed to its interference with bacterial QS and its expression. Furthermore, ARC showed mild effect on mammalian erythrocytes, low probability to induce resistance and synergistically combined with antibiotics. In summary, the promising anti-virulence properties of ARC indicate its potential as an effective supplement to conventional antibiotics for treating severe P. aeruginosa infections.

• YAKHAK HOEJI
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• v.21 no.4
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• pp.211-213
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• 1977

Since ampicillin, one of the important semi-synthetic derivatives of penicillins, is restricted in use because of its unfavorable physico-chemical and pharmacological properties, the author synthesized a new derivative, methampicillin lysinate and its physical and characteristics were determined. The antibacterial activity of this compound against ten species of Gram positive and negative bacteria in vitro showed that it was more active to Gram negative bactria than the positive and that was three times more potent than ampicillin trihydrate.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.47-53
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• 1998

5.7-Dichloro-8-hydroxyquinaldyl-N-ethylcarbamate, one of the carbamate derivative which are generally used as insecticide, was newly synthesized. Its physical properities were determined and chemical structure was indentified by means of I.R., nmr in addition to elemental analysis. The yield of addition, using triethylamine as catalyst, 5.7-dichloro-8-hydroxyquinaldine and isocyanate was better than that of condensation of 5.7-dichloro-8- hydroxyquinaldine with carbamoylchloride. The effect of the cornpond on rabbit's ileum, and antibacterial activity against Staphylococcus aureus, Salmonella typhi, Escherichia coli, and Pseudomonas aeruginosa were examined. It was observed that the dosage over 100 $\mu$g/ml of the compound relaxed rabbit's ileum and the same dosage of the compound inhibited growth of the above strains of bactera.

• Journal of Applied Biological Chemistry
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• v.49 no.2
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• pp.51-56
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• 2006

Metanolic root extract of Glycine max (L.) Merr. was chromatographed, affording three triterpenoids 1-3. The compound 3 was isolated from microorganism called Fusarium sporotrichioides but never been isolated from any plant sources. Compounds 1-3 showed cytotoxic activity against HT-59 human cancer cell line with $IC_{50}$ values of 62.9, 20.0, and $44.2{\mu}M$, respectively. Compound 3 showed significant activities against Gram-positive bacterial such as Bacillus cereus, Bacillus subtilis, and Staphylococcs aureus.

• Archives of Pharmacal Research
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• v.28 no.8
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• pp.889-891
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• 2005

Two ergosterins and two triterpenoids were isolated from the dried fruit bodies of Ascomyce Bulgaria inquinans. By means of chemical (hydrolysis) and spectroscopic methods (NMR, EIMS), their structures were established as betuinic acid (1), cerevisterol (2), (24R)ergosta-7, $22E­diene-3\beta,\;5\alpha,\;6\beta-triol-3-O-palmitate$ (3) and ursolic acid (4). Compound 3 is a new compound.

• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.59-62
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• 2001

The dried fruit-body of Daedaleopsis tricolor was extracted by the petroleum ether. The extracts were purified by liquid-liquid extraction, column chromatography, and recrystallization. The purified compound was a colorless orthorhombic crystal form. Its melting point, molecular weight and molar extinction coefficient $(\varepsilon)$ were estimated $168-170^{\circ}C$, 424 and 3,935 at 208 nm, respectively. Its structure was elucidated to be 20(29)-lupen-3-one by UV-Vis, FT-IR, NMR and X-ray crystallographic analysis. It showed antifungal activities against Saccharomyces cerevisiae and Microsporum gypseum, and antibacterial activities against Escherichia coli, Proteus vulgaris, Pseudomonas pyocyanea, Bacillus subtilis, and Staphylococcus aureus. In addition, this compound showed an antioxidative activity on lipid-peroxidation by 6.4%.

• Korean Journal of Plant Resources
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• v.21 no.6
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• pp.431-434
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• 2008

Dental caries is the destruction of the enamel of teeth by Streptoccus mutans. S. mutans has been isolated from human dental plaque and is associated with the initial development of enamel lesions. We have studied the antibacterial action of the fruit of Callistemon citrin us against a cariogenic bacterium, S. mutans. From the fruit of C. citrinus, piceatannol (3,3',4',5-tetrahydroxystilbene) was isolated by repeated column chromatography with $SiO_2$ and Sephadex LH-20. Its structure was elucidated by instrumental analysis using 1D-NMR, 2D-NMR and EI-MS. This compound was isolated from the fruit of C. citrin us for the first time. The anticarcinogenic activity of this compound was determined by using agar well-diffusion method and minimal inhibition concentration (MIC).

• ALGAE
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• v.29 no.1
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• pp.47-55
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• 2014

To develop effective and safe acne vulgaris therapies with a continuing demand for new solutions, we investigated unique efficacy of an antibacterial agent from marine brown alga Eisenia bicyclis in treating acne vulgaris. The methanolic extract of E. bicyclis exhibited potential antibacterial activity against acne-related bacteria. The ethyl acetate fraction showed the strongest antibacterial activity against the bacteria among solvent fractions. Six compounds (1-6), previously isolated from the ethyl acetate fraction of E. bicyclis, were evaluated for antibacterial activity against acne-related bacteria. Among them, compound 2 (fucofuroeckol-A [FF]) exhibited the highest antibacterial activity against acne-related bacteria with a minimum inhibitory concentration (MIC) ranging from 32 to $128{\mu}g\;mL^{-1}$. Furthermore, FF clearly reversed the high-level erythromycin and lincomycin resistance of Propionibacterium acnes. The MIC values of erythromycin against P. acnes were dramatically reduced from 2,048 to $1.0{\mu}g\;mL^{-1}$ in combination with MIC of FF ($64{\mu}g\;mL^{-1}$). The fractional inhibitory concentration indices of erythromycin and lincomycin were measured from 0.500 to 0.751 in combination with 32 or $64{\mu}g\;mL^{-1}$ of FF against all tested P. acnes strains, suggesting that FF-erythromycin and FF-lincomycin combinations exert a weak synergistic effect against P. acnes. The results of this study suggest that the compounds derived from E. bicyclis can be a potential source of natural antibacterial agents and a pharmaceutical component against acnerelated bacteria.

• Polymer(Korea)
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• v.26 no.3
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• pp.389-399
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• 2002

Poly (ethylene terephthalate) (PET) fibers were modified by deep UV irradiation which was produced by a low pressure mercury lamp. FT-IR and XPS analyses were used to elucidate the surface chemical composition of PET fibers treated with UV. Relative $O_{1s}$ intensity increased considerably and it was found that oxygen was incorporated in the form of COO on the fiber surface. FT-IR and XPS analyses proved the existence of carboxylic groups on the surfaces and the adsorption test of cationic compound further supported these results. The concentration of carboxylic acid group on the surface increased remarkably with Increasing irradiation time. XPS analysis and adsorption experiments proved that the surface structure of the UV-irradiated PET fibers were stable for 12 months. Antibacterial property and the deodorization rate of UV-irradiated PET fibers adsorbed with the berberine compound were investigated. Reduction rates of bacteria increased by about 21 to 99% compared to unradiated PET fiber. Deodorization rates of 23% for unradiated PET fiber increased to about 75% for 30 min irradiated samples.s.