• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.225-234
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• 2008

Recently interesting in development of antimicrobial agent from natural origin has been increased in these days. Many studies have been reported antimicrobial effect of Horseradish(Armoracia rusticana) root extracts against various microorganisms such as Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, Vibrio parahaemolyticu, Staphylococcus aureus, Bacillus subtilis, Aspergillus parasiticus, Helicobacter pylori. The main component related to antimicrobial activity in horseradish is well known as allyl isothiocyanate(AIT). In this study, we investigated the antimicrobial effects of Horseradish(Armoracia rusticana) root extracts against Streptococcus mutans isolated from human dental plaque, Streptococcus mutans reference strain and compared with that of chlorhexidine. Horseradish root extracts and chlorhexidine were tested to determine their minimum inhibitory concentration( MIC) and minimum bactericidal concentration(MBC). The result of this study can be summerized as follows; 1. Horseradish root extracts showed antimicrobial effect against both S. mutans isolated strain and reference strain, their MIC were respectively $0.083{\sim}0.25%$ ($833.33{\sim}2500 ppm$), 0.25% (2500 ppm). Horseradish root extracts showed antimicrobial effect against S. mutans isolated strain at same or slightly lower concentration compared with MIC of reference strain. 2. $0.083{\sim}0.25%$ horseradish root extracts showed similar antimicrobial effect with chlorhexidine ($0.0021{\sim}0.0041%$).

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.69-74
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• 2003

Antimicrobial effect of Schizandra chinensis and pine neddle against various pathogens relate to acne (comedones). Ethanol extracts of Schizandra chinensis and pine neddle showed antimicrobial activity against Malassezia furfur Staphylococcus epidermidis and Propionibacterium acnes . The growth of M. fufur and S. epidermidis was inhibited completely by addition of 0.12% Schizandra chinensis extract to YM broth (YM) and tryptic soy broth (TSB) after 24 h incubation. The growth of Propionibacterium acnes was completely inhibited on YM and TSB containing 0.06% of ethanol extract of Schizandra chinensis and pine neddle, respectively. Minimum inhibitory concentration (MIC) of Schizandra chinensis and pine neddle against P. acnes was 0.0075% (75 $\mu\textrm{g}$/mL). The antimicrobial activities of Schizandra chinensis and pine noddle did not decrease apparantly by heat treatment at $80^{\circ}C$ for 30 min, 10$0^{\circ}C$ for 30 min and $121^{\circ}C$ for 15 min, respectively.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.11
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• pp.1286-1293
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• 1988

A general closed form expression for the channel length of the self-aligned double-diffused MOS transistor is obtained from the 2-dimensional Gaussian doping profile. The proposed model in this paper is composed of the doping concentration of the substrate, the final surface doping concentration and the vertical junction depth of the each double-diffused region. The calculated channel length is in good agreement with the experimental results. Also, the optimum channel structure for the prevention of the channel puncthrough is obtained by the averaged doping concentration in the channel region. A correspondence between the results of device simulation of channel punchthrough and the estimations of simplified model is confirmed.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.405-413
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• 2010

Fig (Ficus carica L.) belongs to the mulberry tree (Moraceae) which is one of the oldest fruits in the world. It has been used as a digestion promoter and a cure for ulcerative inflammation and eruption in Korea. The present study investigated the antimicrobial activity of methanol (MeOH) extract of fig leaves against methicillin-resistant Staphylococcus aureus (MRSA) isolated in clinic. The MeOH extract (MICs, 2.5 to 20 mg/mL; MBCs, 5 to 20 mg/mL) was demonstrated as antibacterial activity in isolates MRSA 1-20. The administration of the MeOH extract in combination with oxacillin or ampicillin induced a reduction of ${\geq}$4-8-fold in all tested bacteria, which was considered to be synergistic based on a FICI of ${\leq}$0.375-0.5. Furthermore, time-kill study was found that a combination of MeOH extract with oxacillin or ampicillin produced a more rapid decrease in the concentration of bacteria CFU/mL than MeOH extract alone. The results suggest that fig leaves could be employed as a natural antibacterial agent in MRSA infection care products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1353-1360
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• 2011

This study was performed to investigate the antimicrobial effects against food-borne pathogens and antioxidant activity of Rhododendron brachycarpum ethanol-extract. The antimicrobial activity of the extract was determined using a paper disc-diffusion method, and the diameter of the clear zone was measured. The diameter of the clear zone in the presence of 10 mg of extract was maximal against Bacillus cereus among the three tested Gram-positive bacteria and against Escherichia coli O157:H7 among the five tested Gram-negative bacteria. Analysis of the minimum inhibitory concentration (MIC) showed that the extract exhibited a similar efficacy as that of sorbic acid, a well-known chemical preservative. The growth inhibitory effects of the extract at concentrations of 250, 500, 1,000, and 2,000 mg/L on food-borne pathogens were determined against Staphylococcus aureus, Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7. Growth of the microorganisms was not affected by the extract at concentrations up to 250 mg/L, but it was significantly (p<0.05) inhibited by the extract at concentrations higher than 1,000 mg/L. The antioxidant effects of the extract were examined via measurement of DPPH radical scavenging activity, inhibition of reactive oxygen species (ROS) generation using fluorescent dichlorofluorescien (DCF) assay, and prevention of peroxyl radical- and hydroxyl radical-induced supercoiled DNA breakage. The $IC_{50}$ of the extract for DPPH radical scavenging activity was about half that of ${\alpha}$-tocopherol, which was used as a positive control. DCF fluorescence intensity decreased as the concentration of the extract increased, demonstrating that ROS generation was inhibited in a concentration-dependent manner. The ROS inhibitory effect of the extract was higher than that of ascorbic acid. The extract prevented supercoiled DNA strand breakage induced by peroxyl radical and hydroxyl radical. Thus, the results of the present study demonstrate that the extract exhibits antimicrobial effects against food-borne pathogens as well as potent antioxidant capacity, suggesting that R. brachycarpum could be used as a natural antibacterial agent and effective antioxidant in food.

• Journal of Convergence for Information Technology
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• v.10 no.4
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• pp.104-114
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• 2020

We investigated the best antibiotics using blending oils after screening 11 kinds of essential oil known as antibiotics from plants. The minimum inhibitory concentration (MIC) and the minimum killing concentration (MBC) were found to be essential for essential oils B and E to inhibit target bacteria. All gram-positive bacteria containing S. aureus used in this experiment were shown highly antibiotic activity. And only A. baumanii in gram-positive bacteria and C. albicans in fungi were shown highly antibiotic activity. The essential oils used in our experiments showed better antibiotic activity compared to major studies using natural antibiotics with excellent antibiotic activity and essential oils from natural medicine. It is not known what mechanism of antimicrobial activity the essential oil used in the test has, but it is interpreted as a synthetic inhibitory mechanism of cell wall compared with other previous studies. From these results, it is expected that some substances or functional products with antibiotic activity will be developed.

• Food Science and Preservation
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• v.11 no.2
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• pp.207-213
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• 2004

Methanol extracts were prepared from 32 medicinal herbs of the extracts were tested their microbial inhibition activities against food borne pathogens and/or food poisoning microorganisms, food-related bacteria and yeast. Methanol extracts of Cinnamomum cassia, Paeonia suffruticosa, Alnus japonica, Eugenio caryophyllata and Illicium verum exhibited antimicrobial activity for the microorganisms tested, except lactic acid bacteria and yeast. Minimum inhibitory concentrations(MIC) were about 5 mg/mL for Bacillus subtilis, Staphylococcus epidermidis and Pseudomonas aeruginosa. Cell growth of lactic acid bacteria was inhibitied, but greatly on Leuconostoc mesenteroides. The phenolic compound contents were 10.98 mg/g, 10.31 mg/g, 8.55 mg/g and 6.69 mg/g in Thea sinensis, Eugenia caryophyllata, Alnus japonica and Artenisia capillaris, respectively. Antimicrobial activity appeared to be related to phenol compound content in medicinal herbs. The methanol extracts of medicinal herbs could be suitable for the development of a food preservative.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1227-1232
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• 2003

The solvent extracts of the aerial part of Artemisia capillaris extracted by using several solvents with different polarities were prepared and their antimicrobial activities were examined. The antimicrobial activities and cell growth inhibitions were investigated to each strain with the different concentrations of the aerial part of Artemisia capillaris Acetone extract showed the highest antimicrobial activity. Minimum inhibitory concentrations (MIC) for each strain were appeared to 20 mg/mL at Staphylococcus aureus and Bacillus subtilis, 40 mg/mL at Vibrio parahaemolyticus, and 80 mg/mL at Salmonella tyhimurium. The cell growth inhibitions were shown on Staphylococcus aureus, Bacillus subtilis, Vibrio parahaemolyticus, and Salmonella typhimurium for 48 hours. The acetone extract was further fractionated sequentially with hexane, chloroform, ethyl acetate, and butanol for purifying crude acetone extract. The solvent fraction of hexane, chloroform, ethyl acetate, and butanol showed the different antimicrobial activity, respectively.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.348-354
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• 1997

This study was designed to evaluate the effects of garlic extracts of various concentrations on the growth of various pathogens and human colon cancer cell lines in vitro. For antibacterial effects against microorganisms, minimal inhibition concentrations (MIC) of alliin were from 5,000 to 20,000 ppm. MIC of ethanol extract were from 1,250 to 10,000 ppm. For cytotoxic effect of alliin and ethanol extract against human colon cancer cell lines (HCT-15), the growth rates of the cancer cells in medium containing alliin and ethanol extract were inhibited gradually to a significant degree in proportion to the increase of these concentration. Morphology of HCT-15 cells in medium containing alliin and ethanol extract were seen to be shrinked and fragmented. The results show that the causes of the antibacterial and cytotoxic effect against a wide range are thermostable substances isolated by the ethanol.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.242-249
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• 2003

Antimicrobial activity of Caesalpina sappan L. extract (CS extract) against animal husbandry disease-related bacteria was studied. The CS extracts showed a significant antimicrobial activity against Gram(+) bacteria and this antimicrobial activity was most significant against Staphylococcus epidermidis. Minimum inhibitory concentrations (MIC) of CS was in the range of 0.8∼16 mg/ml and 0.8∼10 mg/ml, in the case of MeOH extracts and EtOH extracts, respectively. In addition, the antimicrobial activity of each solvent fraction was most significant with EtOAc layer. The antimicrobial activities of CS extracts against most microbial strains were stable by either heat treatment or acid treatment, whereas those against S. aureus and Sal. typhimurium were reduced by acid treatment. The inhibitory effect of CS extracts on microbial cell growth was further examined by the addition of 0, 100, 300, and 500 ppm of CS extracts into growth medium. The growth of gram(+) bacteria, S. aureus and S. epidermidis, was inhibited for 72 hours in all ranges of CS extracts added, but the growth of gram(-) bacteria was only inhibited when at least 100 ppm of CS extracts were added. Taken together, the antimicrobial activities of CS extracts were more effective against gram(+) bacteria compared to those against gram(-) bacteria.