• Title/Summary/Keyword: $MIC_{50}$

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Antimicrobial Property of the Ethanol Extract from Salvia miltiorrhiza (단삼 추출물의 항균특성)

  • 목종수;김영목;김신희;장동석
    • Journal of Food Hygiene and Safety
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    • v.10 no.1
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    • pp.23-28
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    • 1995
  • The effect of the ethanol extract from salviae miltiorrhizae radix (Salvia miltiorrhiza) on the microbial growht and the stability of the extracted antimicrobial material were investigated. The ethanol extract had strong growth inhibition activity (MIC, 3.13~50.0 $\mu\textrm{g}$/ml) against Gram-positive bacteria such as B. subtilis, L. monocytogenes and S. aureus. Among Gram-positive bacteria tested, B. subtilis was the most susceptible to the extracted substance. While the antimicrobial activity of the ethanol extract was weak (MIC, 400~800 $\mu\textrm{g}$/ml) to E. coli and yeasts (C. albicans, Sacch. diastaticus). The ethanol extract had bactericidal action at higher concentration than MIC against B. subtilis, while the extract had only bacteriostatic action against S. aureus. The extracted antimicrobial substance was stable in the pH range of 4.0 to 10.0, heat treatment at 121$^{\circ}C$ for 15 min, and freezing and thawing

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황련의 증량에 따른 전탕액이 Pseudomonas aeruginosa에 미치는 항균효과에 대한 실험적 연구

  • Seo, Hyeong-Sik
    • Journal of Pharmacopuncture
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    • v.10 no.1 s.22
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    • pp.17-21
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    • 2007
  • Objective : This experimental study was performed to investigate the effect of Coptidis rhizoma extract compared with quantity on Pseudomonas aeruginosa that induce keratitis. Methods : MIC was measured by dropping to 50 ${\mu}l$ according to density Coptidis rhizoma extract(100%, 10%, 1%, 0.1%) compared with quantity(40g, 80g, 120g, 160g). Anti-bacterial potency was measured by the size of inhibition zone with change of volume. Results : MIC on Pseudomonas aeruginosa in Coptidis rhizoma extract compared with quantity(40g, 80g, 120g, 160g) was not showed all samples(100%, 10%, 1%, 0.1%). Conclusions : Coptidis rhizoma extract compared with quantity was not showed anti-bacterial potency on Pseudomonas aeruginosa. The results differ that Coptidis rhizoma extract was showed anti-bacterial potency in 1999 year. Anti-bacterial Potency of Coptidis rhizoma extract compared with quantity on Pseudomonas aeruginosa must be studied.

Preparation of Hetero-Chitooligosaccharides and Their Antimicrobial Activity on Vibrio parahaemolyticus

  • Park, Pyo-Jam;Lee, Hun-Ku;Kim, Se-Kwon
    • Journal of Microbiology and Biotechnology
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    • v.14 no.1
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    • pp.41-47
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    • 2004
  • This study was performed to investigate the antimicrobial effects of hetero-chitosans and their oligosaccharides on the halophilic bacterium, Vibrio parahaemolyticus. Nine classes of hetero-chitosan oligosaccharides were prepared based on their molecular weights, using an ultrafiltration membrane reactor system with chitosanase and celluase, from partially different deacetylated chitosans, 90%, 75%, and 50% deacetylated chitosan, respectively. Thirty-two strains of V. parahaemolyticus were isolated from various marine organisms such as shellfish, shrimps, octopus, and seabirds. Seventy-five percent deacetylated chitosan showed the highest antimicrobial acitivity. The minimal inhibitory concentration (MIC) was 0.5 mg/ml on 14 strains of V. parahaemolyticus, and MIC of the rest strains (18 strains) was 1.0 mg/ml. In addition, MIC of most hetero-chitosan oligosaccharides was 8.0 mg/ml. The results revealed that the antimicrobial effects of hetero-chitosans and their oligosaccharides against V. parahaemolyticus depend on the degree of deacetylation, their molecular weights, and strains tested.

Comparative Superiority of in vitro Activity of DW-224a Supported by the Downward MIC Distribution in Ciprofloxacin-resistant Staphylococcus aureus (시프로플록사신 내성 황색 포도상 구균에서 MIC의 하향 분포로 입증된 DW-224a의 in vitro 항균 활성의 비교 우수성)

  • Yoon, Eun-Jeong;Lee, Chun-Yeong;Lee, Jong-Seo;Choe, Eung-Chil;Shim, Mi-Ja
    • Journal of Pharmaceutical Investigation
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    • v.39 no.6
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    • pp.431-435
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    • 2009
  • The comparative superior in vitro activity of DW-224a was supported by the downward MIC distribution due to the weakened influence of alterations within target enzymes in ciprofloxacin-resistant Staphylococcus aureus. The MI$C_{50}$ for DW-224a was 4 $\mu$g/mL, similar to that of gemifloxacin, 8-fold less than that of sparfloxacin and 16-over-fold less than that of ciprofloxacin. We constructed combinations of amino acid changes, located at codon 80, 83 or 84 within GrlA and 84, 85 or 88 within GyrA, which were associated with MIC increase. The amino acid changes were less influential to the MIC of DW-224a compared to those of other fluoroquinolones, and it was verified from the requirement of a total of two GrlA- and two GyrA-alterations to reach the MIC of DW-224a over 32 $\mu$g/mL.

Solvent Fractionation of Fig Leaves and its Antimicrobial Activity (무화과 잎의 용매분획 및 항미생물 활성)

  • Kang, Seong-Kuk;Chung, Hee-Jong
    • Applied Biological Chemistry
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    • v.38 no.4
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    • pp.289-292
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    • 1995
  • Fig leaves were extracted with methanol and then fractionated with ethyl acetate and various buffers to get active fractions, and their antimicrobial activities in each fraction were determined. Acidic fraction and phenolic fraction of fig leaves showed strong antimicrobial activities, but the basic fraction and neutral fraction did not show any activities. The degree of antimicrobial activities in phenolic fraction against tested bacteria were higher than those in acidic fraction, but these against yeasts and mold were almost equivalent to those in acidic fraction. Especially, phenolic fraction showed the strongest activities against Staphylococcuns aureus and Pseudomonas aeruginosa. Although there were some differences among microorganisms, minimum inhibition concentrations(MIC) in acidic and phenolic fractions against tested microorganisms were 0.05 to 0.1 g eq./ml and 0.01 to 0.25 g eq./ml, on the basis of fresh sample weight, respectively. Minimum lethal concentrations(MLC) in acidic and phenolic fractions were 0.25 to 2.00 g eq./ml and 0.05 to 1.50 g eq./ml, respectively. These supposed the antimicrobial activities in phenolic fraction were generally higher than those in acidic fraction and also phenolic fraction had lower MIC and MLC values than acidic fraction.

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Anti-Salmonella activity of a flavonone from Butea frondosa bark in mice

  • Mishra, Uma Shankar;Dutta, Noton Kumar;Mazumdar, Kaushiki;Mahapatra, Santosh Kumar;Chakraborty, Pronobesh;Dastidar, Sujata G
    • Advances in Traditional Medicine
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    • v.8 no.4
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    • pp.339-348
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    • 2008
  • Butea frondosa has been used traditionally as a topical formulation in the treatment of many diseases and disorders. Two compounds [BF-1 (crystalline flavonol quercetin) and BF-2 (tannin) from ethyl acetate fraction of ethanolic extract] were isolated from the bark of Butea frondosa. The stereostructures of the compounds were determined on the basis of chemical and physicochemical evidence. BF-1 and BF-2 were screened in vitro for possible antibacterial property against 112 bacteria comprising 3 genera of Gram-positive and 12 genera of Gram-negative types. It was found that both BF-1 and BF-2 exhibited inhibitory activity against several bacteria. Most of these strains were inhibited by BF-1 at $50-200\;{\mu}g/ml$, while BF-2 ($MIC_{50}$ $400\;{\mu}g/ml$) was much less active. The bacteria could be arranged in the decreasing order of sensitivity towards BF-1 in the following manner: S. aureus, Bacillus spp., Salmonella spp., Vibrio spp., Shigella spp., E. coli and Pseudomonas spp. The $MIC_{50}$ of the compound was $50\;{\mu}g/ml$ while the $MIC_{90}$ was $100\;{\mu}g/ml$. The decreasing order of sensitivity towards BF-2 was V. cholerae, Bacillus spp., S. aureus, V. parahaemolyticus, Salmonella spp. and Proteus spp. BF-1 was bactericidal in action. In vivo studies with this extract showed that it could offer statistically significant protection (p < 0.01) to mice challenged with a virulent bacterium. The inhibitory activity of Butea frondosa against Gram-positive and Gram-negative bacteria indicates its usefulness in the treatment of common bacterial infections. The potentiality of BF-1 as an antibacterial agent may be confirmed further by pharmacological studies.

Bacteriological Study of Erysipelothrix rhusiopathiae Isolated from the Pigs in Youngnam Area (영남지방 돼지에서 분리한 Erysipelothrix rhusiopathiae의 세균학)

  • 백영숙;이진술;김영은;김봉환
    • Korean Journal of Veterinary Service
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    • v.14 no.1
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    • pp.49-61
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    • 1991
  • The present study was conducted to investigate biochemical, serologic, and pathogenic characteristic of E. rhusiopathiae isolated from the cases of acute septicemic swine erysipelas in Youngnam provinces during the period from June 1988 to September 1990. The majority of biochemical and cultural properties of E. rhusiopathiae isolated from pigs affected with acute erysipelas were identical to those of the standard strain employed. All of the 45 isolates were serotype la. All isolates were highly susceptible to penicillin G, lincomycin, cephalothin, ampicillin, erythromycin (MIC : 0.025-0.78IU or ${\mu}g$ / ml ), and moderately susceptible to oleandomycin, oxytetracycline, chloramphenicol (MIC : 0.78-25${\mu}g$ / ml ). Kanamycin and sulfadimethoxine showed no activity against the isolates(MIC : >400${\mu}g$ / ml ). The MICs of dihydrostreptomycin presented two distribution peaks ; of 45 strains, 5(11.1%) were resistant to dihydrostreptomycin(MIC : 400${\mu}g$ / ml ). All of 5 selected isolates were pathogenic for mite and $LD_{50}$ was $3.7{\times}10^3$viable cells. Mice immunized subcutaneously with live vaccine did not die after challenge to virulent isolates of E. rhusiopathiae.

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Effects of Solvents and Extracting Condition on the Antimicrobial Activity of Salviae miltiorrhizae Radix (Saliva miltiorrhiza ) Extract (용매와 추출조건에 따른 단삼 (Salvia mitiorrhiza) 추출물의 항균력)

  • 목종수;박욱연;김영목;장동석
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.23 no.6
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    • pp.1001-1007
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    • 1994
  • In order to develop a natural food preservative, dried salviae miltiorrhizae radix (Salvia miltiorrhiza) was extracted with several solvents, and then antimicrobial activity was investigated. The optimum extracting condition for the antimicrobial sustance from the sample, minimal inhibitory concentration (MIC) of the extracted substance against microorganisms were also examined. Antimicrobial activity of the initial ethanol extract from the sample was the strongest compared to those of other solvent extracts such as n-hexane, acetone, butanol, methanol and water. the optimum extractingcondition for antimicrobial substance from the sample was shaking extraction for 2 hours at room temperature incase that 10 volumes of absolute ethanol was added to crushed Saliva Miltiorrhiza. The ethanol extract had strong growth inhibition activity against Gram-positive Bacteria (MIC, 3.13-50$\mu\textrm{g}$/ml) such as B. cereus, B, subtilis, L. minocytogenes, S. aureus, Sc. Mutans. Among Grampositive bacteria tested, Bacillus species was the most susceptibile to the extracted substance. The antimicrobial activity of the ethanol extract from the sample was weak to Gram -negative bacteria yeasts, for example MIC for Gram-negative bacteria and yeasts was 0.8mg/ml and 0.4-0.8mg/ml , respectively.

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Preparation and Antibacterial Properties of Quatenary Amine Chitosan (4급 아민 키토산의 제조 및 항균특성)

  • Cho, Suk-Hyung;Kim, Young-Jun;Cho, Jae-Chul;Moh, Sang-Hyun
    • Proceedings of the KAIS Fall Conference
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    • 2011.05b
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    • pp.937-940
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    • 2011
  • 물/유기용매의 혼합용액에 키토산을 분산시키고 이 현탁액에 글리시딜 트리알킬 암모늄염, 글리시딜 아릴염 등의 에테르 시약을 상온에서 현탁상태로 반응시켜 4급화 키토산을 제조하는 새로은 방법을 개발하였다. 이 방법으로 합성한 결과 수득율이 90%이상이었으며 후처리과정이 필요없었다. 4급화 키토산의 균에 대한 최소저지농도(MIC)를 조사한 결과 E. coli O157:H7 균주의 MIC는 0.007%-0.01%(70-100ppm)로 추정되었고 V. vulnificus 균주의 MIC는 0.005%(50ppm)정도이고 V.vulnificus 균주의 MIC는 0.007%(70ppm)이었다. 작물에 대한 항균성을 알아보기 위하여 4N-키토산의 항균 활성만이 검정되었는데, 4N-키토산은 고추 역병균인 P. capsici에 대하여 가장 높은 항균 활성을 보여 4,000 ppm에서부터 키토산 무첨가 대조구에 비하여 항균활성을 보였으며 P. capsici보다는 약하지만 잿빛곰팡이병균 B. cinerea에 대하여도 약간의 항균 활성을 보이고 있어, 16,000 ppm에서는 항균서이 뚜렷이 나타났으나 고추 탄저병균인 C. gloeosporioides에 대해서는 16,000 ppm 이라는 높은 농도에서도 항균 활성을 전혀 보이고 있지 않았다.

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Antibacterial Activities of Bamboo Sap Against Salmonella Typhimurium and Inhibitory Effects in a Model Food System (죽력의 Salmonella typhimurium 등에 대한 항세균 활성과 Model Food System에서의 생육억제 효과)

  • Chung, Hee-Jong;Ko, Bong-Guk
    • Journal of the Korean Society of Food Culture
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    • v.20 no.6
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    • pp.709-714
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    • 2005
  • Antibacterial activities of the freeze-dried bamboo sap dissolved into the water or 50% ethanol were determined and antimicrobial activity of bamboo sap dissolved into distilled water was most strong with 15 mm of the diameter of inhibiting clear zone against Listeria monocytogenes ATCC 19114 among gram positive bacteria tested, but it did not inhibit Bacillus subtilis ATCC 6633 at all, and the sap was most greatly inhibited the growth of Shigella dysenteriae ATCC 9361 among gram negative bacteria with 15 mm of the diameter of inhibiting clear zone. Bamboo sap dissolved into 50% ethanol most strongly inhibited the growth of L. monocytogenes ATCC 19114 and it also inhibited the growth of B. subtilis ATCC 6633 which did not show any with the sap dissolved into distilled water. The sap dissolved into 50% ethanol was most greatly inhibited the growth of S. dysenteriae ATCC 9361 among gram negative bacteria with 23 mm of the diameter of inhibiting clear zone, and it inhibited Vibrio parahaemolyticus WSDH 22, Vibrio vulnilicus ATCC 29307 and Escherichia coli O157 WSDH 54 with 16 mm of the diameter of inhibiting clear zone. However, Both of the saps dissolved in distilled water and 50% ethanol did not showed any inhibition against the lactic acid bacteria of Lactobacillus plantarum KCTC and Lactobacillus brevis KCTC. Most of the tested bacteria were more sensitive to the sap dissolved in 50% ethanol than the sap dissolved in distilled water. The lowest minimum inhibitory concentration of the bamboo sap dissolved into 50% ethanol was 0.6 mg eq./disc with L. monocytogenes ATCC 19114, but that of the sap dissolved into distilled water was 0.8 mg eq./disc with Staphylococcus epidermides ATCC 12228, S. dysenteriae ATCC 9361, L. monocytogenes ATCC 19114, Salmonella typhimurium WSU 2380 and V. parahaemolyticus WSDH 22. In a model food system of the sterilized chocolate milk, antibacterial activities of the sap dissolved into 50% ethanol were relatively stronger than those of the sap dissolved into distilled water and the activities against the bacteria tested were very similar each other. These result suggested the bamboo sap can be used as a natural food preservative.