• Archives of Pharmacal Research
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• v.8 no.1
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• pp.21-30
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• 1985

Examination of the constituents of a marine sponge, Aplysina fishtularis, indicated that brominated tyrosine metabolites were mainly responsible for antimicrobial and antineoplastic activities. Halogenated tyrosine metabolites, 2, 6-dibromo-(2), 2-bromo-3-chloro-(3) and 2, 6-dibromo-(5), 5-a mino-2-bromo-6-chloro-(6) and 5-amino-2, 6-dich-loro-(7) 4-hydroxy-2-cyclohexenone-4-acetic acid lactams were identified as the major antineoplastic and antimicrobial principles. Many other brominated tyrosine metabolites were also confirmed, but they did not show antimicrobial and antineoplastic activities.

• Korean Journal of Agricultural Science
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• v.29 no.2
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• pp.78-90
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• 2002

This study was carried out to investigate whether peptide produced from wheat protein by enzyme hydrolysis can be used as a natural antimicrobial agent. Antimicrobial peptide was obtained from wheat protein by protease of 7 species. The produced antimicrobial peptide was purified through ultrafiltration, membrane filtration and HPLC, and molecular weight and amino acid sequence of the purified antimicrobial peptide were determined. Among hydrolysate produced from wheat protein by protease of 7 species, antimicrobial activity was observed for the peptide obtained from Asp. saito protease. The Asp. saito protease did production antimicrobial hydrolysate showing the highest antimicrobial activity at reaction condition of $37^{\circ}C$ and pH 6.0, but not at reaction condition above $50^{\circ}C$. Wheat protein hydrolysate was fractionated by membrane filtration and showed antimicrobial activity between molecular weight 1,000 - 3,000. The antimicrobial activity fraction obtained by membrane filtration was separated through HPLC and showed antimicrobial activity in the peak of retention time 31.1 - 31.8 min. Since after wheat protein protease hydrolysate was heated during 15 min at $121^{\circ}C$, antimicrobial activity was maintained, we could be conviction as heat-stable peptide. Molecular weight of antimicrobial peptide identified by MALDI-mass was 1,633. Amino acid sequence of antimicrobial peptide was cysteine, glycine, prolin, prolin, prolin, valine, valine, alanine, alanine and arginine.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.251-257
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• 2009

Recently, there is much interest in the antimicrobial activity of silver since silver has known to be safe and effective as a disinfectant or an antimicrobial agent against a broad spectrum of microorganisms. Although silver has been applied to various kinds of products due to the effective antimicrobial activity, the quantitative antimicrobial activity or detailed mechanism of silver is not clearly investigated yet, causing the controversy and confusion. In this review paper, we summarized the characteristics, antimicrobial activities and mechanisms, synergistic effects with other antimicrobials, and applicability of silver.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.402-407
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• 2008

The synergistic antimicrobial effect of Achyranthes japonica Nakai (AJN) and Bifidobacterium extracellular factors against Clostridium difficile were measured using a turbidity method. Each broth supernatant of Bifidobacterium infantis ($68.8{\pm}0.02%$) and Bifidobacterium adolescentis ($33.2{\pm}0.2%$) obtained by adding ethyl acetate soluble fractionate from A. japonica Nakai ethanolic extracts (AJNEA, 100 ppm, no inhibition) showed high synergistic antimicrobial activity against C. difficile. In addition, the antimicrobial activity in a laboratory medium and yogurt products against C. difficile were evaluated. In yogurt prepared with a starter 5 (Lactobacillus acidophilus: Streptococcus thermophilus: B. adolescentis =1 : 1 : 1) and a starter 4 (L. acidophilus: S. thermophilus: B. infantis=1 : 1 : 1) and 0.5% AJNEA powder, high antimicrobial effects were recorded that measured 79.0 and 65.2%, respectively. The results indicated the potential of AJN extract for use as an antimicrobial agent. In addition, the efficiency of the antimicrobial activity of the extracts was further improved in combination with lactic acid bacteria, which suggests that they have the potential to be used as a highly effective antibiotic-tolerant microorganism prevention system. Such a strategy can be used for alternative drugs or functional food additives for treatment of antibiotic-associated diarrhea.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.679-682
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• 2008

A lactic acid bacterium producing an antimicrobial substance against Escherichia coli O157:H7 was isolated from raw milk and identified as Lactobacillus amylovorus ME-1. In addition to E. coli O157 :H7, the antimicrobial substance also inhibited the growth of Bacillus cereus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pyrogenes, and Yersinia enterocolitica. The antimicrobial substance was stable at pH 2-12 and $121^{\circ}C$ for 15 min and insensitive to proteinase K, protease, amylase, and catalase. Purification of the antimicrobial substance was conducted through methanol and acetonitrile/ethylacetate extraction, ultrafiltration with a 500 Da cutoff, thin layer chromatography (TLC) with silicagel 60, and high performance liquid chromatography (HPLC) with a $C_{18}$ reverse phase column. The ${\lambda}_{max}$ of the purified antimicrobial substance was determined as 192 nm by ultra violet (UV) scanning, while the molecular weight was estimated as 453 Da based on the mass spectrum. Accordingly, the current results suggest that the antimicrobial substance from the L. amylovorus ME-1 was not a bacteriocin, but rather a new non-proteinaceous substance distinct from acidophilin, acidolin, diacetyl, and reuterin.

• Microbiology and Biotechnology Letters
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• v.39 no.1
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• pp.1-8
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• 2011

The antimicrobial effects of silver (Ag) ion or salts are well known. Recently, silver nanoparticle is attracting an interest in a wide variety of fields since it has been known to be safe and effective as an antimicrobial agent against a broad spectrum of microorganisms. Although silver nanoparticle has been applied to various kinds of products owing to its potent antimicrobial activity, the effects of silver nanoparticle on microorganisms and antimicrobial mechanism have not been revealed clearly. In this paper, we summarized the characteristics, antimicrobial activities and mechanisms, cytotoxicity and applicability of silver nanoparticle.

• The Korean Journal of Community Living Science
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• v.15 no.2
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• pp.101-107
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• 2004

Many studies have presented results about the antioxidative and antimicrobial activities of Dandelions(Taraxacum officinale). There has yet to be a study which makes comparisons based on the variety or parts of the Dandelion. To compare the physiological activity, antioxidative and antimicrobial activities were measured by using methanol extracts of Korean and Western Dandelions. The Dandelions were taken from Uiryeong in Kyungnam province, and antioxidative and antimicrobial activities of the flower, leaf and root were measured. Antioxidative activities of the methanol extracts were examined with a DPPH test. Antimicrobial activities were examined against 5 microorganisms. Bacillus subtilis and Bacillus cereus served as G(+) microorganisms, while Salmonella typhimurium, Staphylococcus aureus, and Eschrichia coli served as G(-) microorganisms. There was no significant difference in the antioxidative activity of the methanol extracts from leaves and roots between varieties. The antioxidative activity of the flower extracts was higher in the Korean than in the Western samples but the highest level of antioxidant was lower than 70%. No significant difference in antimicrobial activities between the varieties was observed. More research using physiological factors other than antioxidative and antimicrobial activities is needed to identify physiological functions and enhance the utilization of Dandelions.

• YAKHAK HOEJI
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• v.40 no.6
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• pp.653-658
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• 1996

As part of our search for less toxic antimicrobial agents from natural resources. rutin was isolated from Sophora japonica and then hydrolyzed to quercetin. Antimicrobial activity of quercetin was tested in vitro against five kinds of gram positive and ten kinds of gram negative bacteria by serial broth dilution method. Among fifteen kinds of bacteria tested, the antimicrobial activity of quercetin was the most potent against Proteus vulgaris showing minimal inhibitory concentration(MIC) of 125 ${\mu}$g/ml. To investigate the effect of antimicrobial combinations of quercetin with four kinds of antibiotics (ampicillin, cefazolin, oxytetracycline and chloramphenicol). the fractional inhibitory concentration index (FICI) was determined by checkerboard assay for each strain. The antimicrobial combinations of quercetin with four kinds of antibiotics resulted in synergism in one instance, additive effect in four instances, but no antagonism was observed.

• Korean Journal of Veterinary Research
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• v.56 no.2
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• pp.91-95
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• 2016

This study was conducted to investigate the prevalence and antimicrobial resistance of Salmonella spp. and Escherichia (E.) coli isolated from ducks in Korea. A total of 400 cecal content samples were collected from 40 duck farms in Korea. Isolated Salmonella spp. and E. coli strains were 83 and 364 of the 400 cecal samples, respectively. The most prevalent serotype among the 83 Salmonella isolates was Salmonella Typhimurium (51 isolates: 61.45%). Resistance to the tested antimicrobial agents by Salmonella isolates was low except for erythromycin, while the resistance of the E. coli isolates to the other tested antimicrobial agents was high and 90.9% (331/364) of E. coli isolates showed multi-antimicrobial resistance. Antimicrobial resistance in duck zoonotic pathogens should be of concern to the Korean duck industry, as these pathogens exhibit a high rate of antimicrobial resistance and pose a potential hazard to public health.

• Food Science and Biotechnology
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• v.16 no.6
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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.