• Journal of dental hygiene science
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• v.15 no.3
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• pp.308-317
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• 2015

This study attempted to identify the possibility of natural herbal extracts as an alternative, preventive agent of caries by comparing antimicrobial activities between natural herbal extracts and mouth rinsing solutions against Streptococcus mutans. Natural herbal plants were extracted with distilled water and ethanol, respectively, to measure the minimum growth inhibitory concentration of S. mutans depending on concentration, and among which, solvents showing high antimicrobial activity were selected to compare their antibiotic effects with those of mouth rinsing solutions. Also, to determine the concentration of natural medicinal herbs that can be used safely in the oral cavity, the extracts were treated to the normal gingival fibroblast cells depending on concentration in order to determine its cytotoxicity using MTT. In terms of the minimum growth inhibition concentration, the growth inhibition of S. mutans was more excellent in the ethanol extract than in the distilled water. When the minimum growth inhibition concentration was compared, Psoralea corylifolia of natural herbal ethanol extracts, and Hexamedine (Bukwang Pharm., Korea) of mouth rinsing solutions inhibited growth of S. mutans at the lowest concentration. When the minimum bactericidal concentration was compared, P. corylifolia of natural herbal extracts, and Hexamedine and Garglin (Dong-A Pharm., Korea) of mouth rinsing solutions eliminated S. mutans at a low concentration. The human gingival fibroblast was treated with natural herbal ethanol extracts at the minimum growth inhibition concentration of 10, 39, and $78{\mu}g/ml$. As the result, no cytotoxicity was found. When this was treated at different minimum bactericidal concentrations, natural herbal ethanol extracts showed cytotoxicity except P. corylifolia.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.40-46
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• 2000

To select the effective fungicides for the control of leaf spot disease of jujube tree (Zizyphus jujuba) caused by Phoma sp., inhibitory effects of 26 fungicides for mycelial growth were investigated at $250{\mu}g\;a.i./m{\ell}$. In the test, eight fungicides were selected and minimum inhibitory concentration (MIC) for mycelial growth and an inhibitory effect for spore germination were investigated. Among the fungicides, myclobutanil, hexaconazole, and triflumizole were excluded in control effect tests because of their relatively high MICs. MICs were ranged $10-50{\mu}g\;a.i./m{\ell}$ for benomyl, carbendazim + kasugamycin (CK), and thiophanate-methyl. triflumizole (TT), and $50-250{\mu}g\;a.i./m{\ell}$ for iprodione + propineb (IT) and iminoctadine-triacelate (IT). However, benomyl and IP showed very low inhibitory effect on conidial germination. When the fungicides were sprayed on the seedlings before the leaves were inoculated with conidial suspension of Phoma sp., the protective values of CK and TT were around 70% at 1,000 ppm and around 90% at 2,000 ppm. The protective values were around 70% at 2,000 ppm (benomyl), 4,000 ppm (IP), and 8,000 ppm (IT). When the fungicides were sprayed after inoculation, benomyl showed the highest curative values of over 90% at 1,000 ppm and the values of CK and TT ranged $70{\sim}80%$ at 1,000 ppm. However, IP and IT had little or no effect on therapy of the disease. IT caused necrotic phytotoxicity on the leaves of jujube seedlings. As results, the best fungicides for the protection of jujube trees from leaf spot disease were CK (2,000 ppm) and TT (2,000 ppm) and for the remedy of the tree, benomyl (1,000 ppm) was the best. Therefore, alternate application of benomyl and CK or TT will be effective in the disease control.

• Korean Journal of Microbiology
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• v.48 no.3
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• pp.212-215
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• 2012

The antimicrobial activity of ursolic acid (UA) and oleanolic acid (OA), both triterpenoid compounds, against methicillin-resistant Staphylococcus aureus (MRSA) is controversial. We examined the antimicrobial effects of UA and OA against 19 strains of MRSA isolated from Koreans by determining minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). The data showed that the methicillin-sensitive strain S. aureus KCTC $1621^T$ was more resistant to UA and OA than that of the MRSA strains. The MBC values of UA and OA against MRSA had broad ranges; 4 to 32 ${\mu}g/ml$ and 16 to >256 ${\mu}g/ml$, respectively. It was difficult to understand the different antimicrobial activities of UA and OA among the MRSA strains, because UA and OA antimicrobial mechanisms are unknown. These results indicate that the antimicrobial effects of UA and OA against MRSA are dependent on resistance to UA and OA in each strain.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.237-244
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• 2009

When the symptom of periapical infection is not released by mechanical instrumentation. anti-microbial agents including antibiosis become necessary in order to remove microorganisms from the root canal. Since anti-microbial agents of natural origins are currently popular, more natural remedies are being sought out. As it turns out, it is well known isothiocyanates (ITCs) in horseradish root extract have anti-microbial activity from many studies. In this research, anti-microbial effects of horseradish root extract and chlorhexidine, a typical anti-microbial agent, were investigated and compared against two kinds of obligate anaerobes. Fusobacterium nucleatum and Prevotella nigrescens, that are often discovered in infected root canal, and Clostridium perfringens, which is resistant to antibiotics and frequently used as a control strain for antibacterial studies 1. The MIC and MBC of horseradish root extract were ranged from 87 to 470 ppm and from 156 to 625 ppm against three kinds of obligate anaerobes, respectively. Horseradish root extract showed the strongest anti-bacterial activity (MBC, 156 ppm) against F. nucleatum and also showed anti-bacterial activity against antibiotic resistant obligate anaerobes. C. perfringens. 2. The MIC and MBC of chlorhexidine were ranged from 3.12 to 6.25 ppm and 10.94 ppm against three kinds of obligate anaerobes, respectively. 3. The MIC with 87-470 ppm of horseradish root exact has the same growth inhibiting effect as the one of 3.12-6.25 ppm of chlorhexidine. Likewise, the MBC with 156-625 ppm of horseradish has the similar bactericidal effect as 10.94 ppm of chlorhexidine.

• 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 Food Hygiene and Safety
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• v.23 no.4
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• pp.309-313
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• 2008

To investigate the antibacterial activity of the traditional bronze alloy Yugi, the cultures of Salmonella spp., Escherichia coli O157, Enterobacter sakazakii, and Bacillus cereus were exposed to the metal coupons of bronze, copper, tin, and stainless steel, and the sterilizing activities were analyzed. Antibacterial efficacy of copper coupon toward S. Typhimurium, E. coli, and E. sakazakii were the highest among them and those were followed by bronze, tin, and then stainless steel in the activity order. However, there was little sterilizing activity on Gram-positive B. cereus. Minimal inhibitory concentrations of cupric ion were 25 ppm for S. Typhimurium, E. coli, and E. sakazakii, and 50 ppm for B. cereus. Yugi bronze alloy showed more rigidity and practicality in comparison with copper, and has been used in Korea. Therefore, the bronze alloy may be more effective to reduce the cross-contamination of S. Typhimurium, E. coli, and E. sakazakii than stainless steel in food processing surface.

• Research in Plant Disease
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• v.23 no.3
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• pp.268-277
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• 2017

Fusarium head bight (FHB) is a devastating disease on major cereal crops worldwide which causes primarily by Fusarium graminearum. Synthetic fungicides are generally used in conventional agriculture to control FHB. Their prolonged usage has led to environmental issues and human health problems. This has prompted interest in developing environmentally friendly biofungicides, including botanical fungicides. In this study, a total 100 plant extracts were tested for antifungal activity against F. graminearum. The crude extract of Pterocarpus santalinus heartwood showed the strongest antifungal activity and contained two antifungal metabolites which were identified as ${\alpha}$-cedrol and widdrol by GC-MS analysis. ${\alpha}$-Cedrol and widdrol isolated from P. santalinus heartwood extract had 31.25 mg/l and 125 mg/l of minimal inhibitory concentration against the spore germination of F. graminearum, and also showed broad spectrum antifungal activities against various plant pathogens. In addition, the wettable powder type formulation of heartwood extract of P. santalinus decreased FHB incidence in dose-dependent manner and suppressed the development of FHB with control values of 87.2% at 250-fold dilution, similar to that of chemical fungicide (92.6% at 2,000-fold dilution). This study suggests that the heartwood extract of P. santalinus could be used as an effective biofungicide for the control of FHB.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1164-1170
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• 2001

Antimutagenic and antimicrobial effects of cucumber extracts were investigated. Antimutagenic effects of cucumber extract against aflatoxin (AFB$_1$) as indirect mutagen and N-methyl-N'-nitro-N-nitrcsoguanidine (MNNG) as direct mutagen using the Ames assay system with Salmonella typhimurium TA100 were studied. 1.25~5.0% of methanol extract exhibited 11 ~ 17% of antimutagenity against AFB$_1$ and 46~85% of antimutagenity against MNNG. Among fractions of methanol extract, hexane fraction exhibited the highest antimutagenic effect against AFB$_1$ (89%) and butanol fraction exhibited the highest antimutagenic effect against MNNG (95%). Antimicrobial effects of cucumber extract were investigated on the eleven microorganisms. Methanol extract showed anitimicrobial effect on eight microorganisms. Among these tested microorganisms, Klebsiella pnemonia KCTC 2208, pseudomonas aeruginosa KCTC 2004 were the most sensitively inhibited with 13 mm clear zone on holo test. Hexane fraction showed anitimicrobial effect only on Vibrio parahaemolyticus KCTC 2471. Chloroform and ethyl acetate fractions showed a weak effect. V. parahaemolyticus showed the lowest minium inhibitory concentration (MIC) (500 ppm) among eleven tested microorganisms by methanol extract. Sterilization effect of 1% methanol extract on P. aeruginosa incubation is 10 times stronger than 0.5% methanol extract. It estimated to need 26 min for the sterilization of 90% P. aeruginosa cell counts by 1% methanol extract but 250 min by 0.5% methanol extract.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.52-59
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• 2000

A rapid assay to determine respiration inhibition of Saccharomyces cerevisiae by chemicals was developed. S. cerevisiae was harvested with two different liquid media, yeast extract-peptone-dextrose (YPD) medium capable of occurring both glucose fermentation and mitochondrial respiration, and non-fermentable carbon-yeast extract (NFY) medium capable of occurring respiration only Wells in 96-well plate were loaded with each cell suspension and various concentrations of 46 fungicides with various modes of action. n NFY medium, the non-fermentable carbon source, ethanol (NFY-E medium), glycerol (NFY-G medium) or lactate (NFY-L medium), was used. After incubation for $1{\sim}3$ days, minimum inhibitory concentrations (MICs) of the chemicals were recorded in the media. Of the 46 inhibitors employed in this study, four inhibitors of fungal respiration by blockage of electron flux in the mitochondrial respiratory chain, azoxystrobin, kresoxim-methyl, metominostrobin, and trifloxystrobin, exhibited strong antifungal activity in all of NFY media, but no activity in YPD medium. In contrast to this, five N-trihalomethylthio fungicides showed much stronger antifungal activities in YPD medium than three NFY media. Eleven fungicides inhibited growth of S. cerevisiae in all media and the other 26 fungicides showed no antifungal activity in all media. Thus, our rapid and efficient in vitro method can be considered as an alternative assay system for respiration inhibitor.

• KSBB Journal
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• v.16 no.4
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• pp.360-364
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• 2001

It is known as the allylisothiocyanate which is extracted from Wasabia koreana\\\\\\\\`s root. It contains 80% of the oil refining material. The allylisothiocyanate as secondary metabolites of Wasabia koreana plant is a possibility of having the high value which is useful. The research observed the allylisothiocyanate material as the basic study for industrializing to make its mass product. Finally, it shows that the antimicrobial and disinfectant effect against the microbe incubated adding 50 ppm allylisothiocyanate for 15 hours.