• The Plant Pathology Journal
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• v.29 no.4
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• pp.386-396
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• 2013

Reactive oxygen species (ROS) generation in tomato plants by Ralstonia solanacearum infection and the role of hydrogen peroxide ($H_2O_2$) and nitric oxide in tomato bacterial wilt control were demonstrated. During disease development of tomato bacterial wilt, accumulation of superoxide anion ($O_2{^-}$) and $H_2O_2$ was observed and lipid peroxidation also occurred in the tomato leaf tissues. High doses of $H_2O_2$ and sodium nitroprusside (SNP) nitric oxide donor showed phytotoxicity to detached tomato leaves 1 day after petiole feeding showing reduced fresh weight. Both $H_2O_2$ and SNP have in vitro antibacterial activities against R. solanacearum in a dose-dependent manner, as well as plant protection in detached tomato leaves against bacterial wilt by $10^6$ and $10^7$ cfu/ml of R. solanacearum. $H_2O_2$- and SNP-mediated protection was also evaluated in pots using soil-drench treatment with the bacterial inoculation, and relative 'area under the disease progressive curve (AUDPC)' was calculated to compare disease protection by $H_2O_2$ and/or SNP with untreated control. Neither $H_2O_2$ nor SNP protect the tomato seedlings from the bacterial wilt, but $H_2O_2$ + SNP mixture significantly decreased disease severity with reduced relative AUDPC. These results suggest that $H_2O_2$ and SNP could be used together to control bacterial wilt in tomato plants as bactericidal agents.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.386-392
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• 2014

The present study was aimed at investigating the antimicrobial activities of licorice's active ingredients. Four samples of licorice ingredients (glycyrrhizin, liquiritin, liquiritigenin, and isoliquiritigenin) were evaluated for their antimicrobial activities against six skin microorganisms. The bioassay applied for determining the antimicrobial effects employed a disc diffusion assay, the minimum inhibitory concentration, and the challenge test. The ingredients showed antibacterial activities. Especially, isoliquiritigenin has significant antimicrobial activities against two Gram-positive (Bacillus subtilis, Propionobacterium acnes) and two Gramnegative (Escherichia coli, Pseudomonas aeruginosa) bacteria. These samples had much higher antimicrobial activities than synthetic preservatives. Our results reveal that liquiritigenin and isoliquiritigenin could be useful compounds for the development of antibacterial agents for the preservation of cosmetics and foods. The two flavonoids, liquiritigenin and isoliquiritigenin, sourced from Korea, China, Uzbekistan, were quantified using HPLC. The results demonstrated that Korean licorice has two flavonoids (liquiritigenin, isoliquiritigenin) in much higher quantities than was observed in the licorice obtained from the two other countries. Thus, isoliquiritigenin and Korean licorice extract represent new candidates for antimicrobial agents.

• The Journal of Korean Obstetrics and Gynecology
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• v.26 no.1
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• pp.1-24
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• 2013

Objectives: The object of this study was to observe the protective effect of Gamijipaesan aqueous extracts(GJS), which has been traditionally used in Korean medicine in obstetrics & gynecological fields as anti-infectious and anti-inflammatory agents, against mastitis induced by Staphylococcus aureus infection in a rat model through antibacterial, antiinflammatory, immunomodulatory, and anti-oxidant effects. Methods: Antibacterial activities of GJS against S. aureus were detected using standard agar microdilution methods, with the effects on the bacterial invasion and intracellular killing of individual test materials in human mammary gland carcinoma cell(MCF-7) and murine macrophages(Raw 264.7) at MIC1/2, MIC and MIC2 concentration levels. In addition, the effects on the cell viability, nitric oxide(NO), tumor necrosis factor(TNF)-${\alpha}$ and interleukin (IL)-6 productions of LPS activated Raw 264.7 cells. The changes on the mammary tissue viable bacterial numbers, myeloperoxidae(MPO), inducible nitric oxide synthetase(iNOS), TNF-${\alpha}$ and IL-6 contents were observed in the S. aureus in vivo intramammary infectious rat model. The anti-bacterial and anti-inflammatory effects were compared with ciprofloxacin and piroxicam, respectively in the present study. Results: MIC of GJS and ciprofloxacin against S. aureus were detected as $0.860{\pm}0.428$ (0.391-1.563) mg/ml and $0.371{\pm}0.262$(0.098-0.782) ${\mu}g/ml$, respectively. In addition, GJS and ciprofloxacin were also showed marked dosage-dependent inhibition of the both bacterial invasion and intracellular killing assays using MCF-7 and Raw 264.7 cells at MIC1/2, MIC and $MIC{\times}2$ concentrations, respectively. $ED_{50}$ against LPS-induced cell viabilities and NO, TNF-${\alpha}$ and IL-6 releases of GJS were detected as 0.72, 0.04, 0.08 and 0.11 mg/ml, and as 19.04, 4.18, 5.37 and 4.27 ${\mu}g/ml$ in piroxicam, respectively. 250 and 500 mg/kg of GJS also inhibit the intramammary bacterial growth, MPO, iNOS, TNF-${\alpha}$ and IL-6 contents in S. aureus in vivo intramammary infected rats, respectively. GJS 500 mg/kg showed quite similar antibacterial and anti-infectious effects as compared with ciprofloxacin 40 mg/kg and also showed similar anti-inflammatory effects as piroxicam 10 mg/kg, in S. aureus in vivo intramammary infectious models. Conclusions: The results obtained in this study suggest that over 250 mg/kg of GJS showed favorable anti-infectious effects against S. aureus infection in a rat model through their antibacterial, anti-inflammatory, immunomodulatory and anti-oxidant effects and therefore expected that GJS can be used as alternative therapies, having both anti-inflammatory and anti-infectious activities. However, more detail mechanism studies should be conducted in future with the efficacy tests of individual herbal composition of GJS and the screening of the biological active compounds in individual herbs. In the present study, GJS 500 mg/kg showed quite similar anti-infectious effects were detected as compared with ciprofloxacin 40 mg/kg treated rats, and also GJS shows quite similar anti-inflammatory effects as compared with piroxicam 10 mg/kg in S. aureus in vivo intramammary infectious rats, but ciprofloxacin did not showed any anti-inflammatory effects, and piroxicam did not showed anti-infectious effects in this study.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.1-14
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• 2005

The maintenance of good oral health in adults is often hindered by oral malodor and periodontal diseases which are known to be commonly caused by some species of Gram-negative anaerobic bacteria, with low sensitivity to common synthetic antibiotics or antibacterial chemical agents. Therefore the development of a nonharmful natural antibacterial oral rinsing remedy against the causative bacteria is thought to be very important. The purpose of this study is to obtain the basic data for development of a nonharmful natural antibacterial oral rinsing remedy using colloidal silver. The author applied colloidal silver solution with concentration of 10, 30, 50, 80 ppm to some strains in species of Prevotella intermedia, Porphyromonas gingivalis, Fusobaterium nucleatum, and evaluated the effects of colloidal silver on the growth of experimental bacterial strains in aspects of minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and growth pattern after incubation for 24, 48, 72 hours. The obtained results were as follows: MIC of colloidal silver solution against experimental strains was 30 ppm in P. intermedia, 10 or 30 ppm in P. gingivalis, and 30, 50, or 80 ppm in F. nucleatum. And MBC of colloidal silver solution against experimental strains was 30 ppm in P. intermedia, 30 or 50 ppm in P. gingivalis, 30 or 80 ppm in F. nucleatum. Therefore it was concluded that colloidal silver exhibited bacteriostatic or/and bacteriocidal effects against some experimental strain. And the inhibition of growth of experimental strains were markedly or considerably exhibited under 30 ppm$\sim$50 ppm of colloidal silver solution for 48 hours$\sim$72 hours in P. intermedia, 10 ppm$\sim$30 ppm for 24 hours$\sim$48 hours in P. gingivalis, 30 ppm for 24 hours in F. nucleatum. These results indicate that the colloidal silver inhibited effectively the growth of some species of Gram-negative anaerobic bacteria by exhibition of bacteriostatic or/and bacteriocidal effects, and can be used as a possible major ingredient of the nonharmful natural antibacterial oral rinsing remedy to oral malodor and periodontal diseases.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.99-103
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• 2007

The antibacterial efficacy of 0.1% (w/v) chitosan solution against Staphylococcus intermedius isolated from a dog with superficial pyoderma was evaluated in vitro and in vivo. The exposure time for the 0.1% chitosan solutions at different pH to be able to eliminate the bacterial cells and the effect of pH of the solutions on antibacterial activity was tested at the same time in vitro. The antibacterial activity of chitosan was compared to other antibacterial agents including 2.5% benzoyl peroxide, 0.5% chlorhexidine acetate, 0.1% chitosan solution combined with 2.5% benzoyl peroxide and chitosan combined with 0.5% chlorhexidine using a modified detergent scrub quantitative technique in 10 adult mongrel dogs in vivo. They were able to eliminate a number of bacteria after the exposure time of 10 minutes at varying degrees according to the pH of the solutions. The antibacterial activity of chitosan was inversely affected by pH with higher activity at lower pH value. The 0.1% chitosan solution was also efficacious against Staphylococcus intermedius in vivo. The combinations of chitosan with benzoyl peroxide and with chlorhexidine were shown to exert higher activity when compared to those of chitosan alone and benzoyl peroxide or chlorhexidine alone. The 0.1% chitosan solution was considered to be efficacious against Staphylococcus intermedius isolated from a dog with superficial pyoderma in both in vivo and in vitro and have a potential for the clinical applications in the treatment or pyoderma in dogs.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.1
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• pp.57-63
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• 2010

To develop natural therapeutic agents for acne vulgaris, we investigated antibacterial and anti-inflammatory effects of various medicinal plant extracts. Among candidate extracts, we selected Psoralea corylifolia L. extract (AC-1) and Magnoliae officinalis extract (AC-2) which showed the relatively high antibacterial effects, and Inula helenium L. extract (ACF-1) and Chrysanthemum zawadskii var. latilobum extract (ACF-2) which showed the relatively high anti-inflammatory effects for further investigations. All of them did not show cytotoxic effects below the concentration of $50{\mu}g/mL$. The antibacterial effects of AC-1, AC-2 and extract complex (AC) against P. acnes were 2.8, 2.5 and 3.2 times higher than that of 10 % salicylic acid respectively. And the antibacterial effect of AC-2 and extract complex against S. aureus were 1.4 and 1.5 times higher than that of 10 % methylparaben respectively. Also, it was shown that ACF-1, ACF-2 and extract complex had anti-inflammatory effects. All of them exhibited inhibitory effects for the secretion of IL-8 and TNF-$\alpha$ from THP-1 cells activated by heat-killed P. acnes. They reduced about 27 %, 38 %, 44 % of IL-8 secretion and 90 %, 88 %, 90 % of TNF-$\alpha$ secretion at concentration of $50{\mu}g/mL$ respectively. These results showed that the complex of medicinal plant extracts, AC-1. AC-2, ACF-1, and ACF-2, had therapeutic effects to acne vulgaris through antibacterial and anti-inflammatory effects. Therefore, we suggest that extract complex of AC-1, AC-2, ACF-1 and ACF-2 may be used as a useful agent for development of natural cosmetics which have therapeutic effects to acne vulgaris.

• Journal of Life Science
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• v.29 no.6
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• pp.671-678
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• 2019

Antibacterial and antioxidant activities of plant sources have attracted a wide range of interest across the world over the last decade. This is due to the growing concern for safe and alternative sources of antibacterial and antioxidant agents. In this study, we focused on the antibacterial and antioxidant activities and the chemical composition of a methanol extract from Viburnum sargentii seeds. The chemical composition was determined by gas chromatography-mass spectroscopy (GC-MS), and the antibacterial activity was screened by a disc diffusion assay. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the microbroth dilution and spread plate method, respectively. The V. sargentii extract showed growth inhibition activity on all tested Gram-positive (Listeria monocytogenes, Staphylococcus aureus, and Staphylococcus saprophyticus) and Gram-negative (Escherichia coli, Pseudomonas putida, and Proteus vulgaris) pathogenic bacteria. The MIC and MBC ranged from 0.156~1.25 mg/ml for Gram-positive and 0.625~5.0 mg/ml for Gram-negative tested bacteria. The GC-MS results revealed the presence of several phytochemicals such as ${\beta}-sitosterol$ and vitamin E, which are known for their pharmacological applications. The antioxidant activities of V. sargentii extract were investigated by three different methods: the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay, the reducing power assay, and the total antioxidant capacity assay. The results showed a concentration-dependent antioxidant potential for all three used methods. In sum, our findings suggest that the methanol extract of V. sargentii seeds has the potential to inhibit the growth of pathogenic bacteria and provide antioxidant compounds, making it therefore worthy of further investigation.

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.30-35
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• 2008

purpose of the study was to synthesize new series of 5-cyano substituted pyrimidine analogues with different substitutions at N1 and 6 positions and to evaluate them for antibacterial and antifungal activities. The desired compounds were synthesized by tertiary condensation of ethylcyanoacetate, substituted thioureas and suitable aldehyde in presence of potassium carbonate using MORE technique. The antibacterial and antifungal activities were evaluated by cup plate method in the concentration of 25 mg. The zone of inhibition was measured in mm. All the compounds have shown significant antibacterial and antifungal activities. The maximum activity was shown by P1 and P5 against S.aureus and E.coli respectively, while P6 has shown significant activity against all types of microorganisms. The compound P8 has been found to be significantly effective against C. albicans. Norfloxacin and griseofulvin were used as standards to compare the activites of synthesized compounds. It is concluded that analogues containing p-hydroxy, p-methoxy substituted phenyl moiety at 6 position have been found to be more potent against gram-positive microorganisms, while analogues lacking these substituents on phenyl moiety possessed gram-negative activity. The compounds having p-dimethylamino substituent on phenyl moiety at 6 positions have shown moderate activity. Further, only fluorine containing analogue at N1 position was found to possess appreciable antifungal activity. This suggests that electron donating substituent on aryl moiety as well as electron withdrawing substituent at N1 plays important role in determining potency of the compounds.

• Journal of Life Science
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• v.27 no.4
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• pp.476-481
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• 2017

Polyphenols are secondary metabolites produced by higher plants and have been used as antiallergic, anticancer, antihypertensive, antiinflammatory, antimicrobial and antioxidant agents. They are generally divided into flavonoids and non-flavonoids. The antimicrobial activity of flavonoids are stronger than that of non-flavonoids. The skeleton structures of flavonoids possessing antimicrobial activity are chalcone, flavan-3-ol (catechin), flavanone, flavone, flavonol and proanthocyanidin. The flavonols are shown antibacterial activity against several gram-positive bacteria (Actinomyces naeslundii, Lactobacillus acidophilus and Staphylococcus aureus) and gram-negative bacteria (Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella melaninogenica and Prevotella oralis). Among of non-flavonoids, caffeic acids, ferulic acids and gallic acids showed antimicrobial activity against gram-positive (Listeria monocytogenes and S. aureus) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). These are found to be more efficient against the E. coli, L. monocytogenes, P. aeruginosa and S. aureus than antibiotics such as gentamicin and streptomycin. The kaempferol and quercetin showed synergistic effect with ciprofloxacin and rifampicin against S. aureus and methicillin resistant S. aureus (MRSA). Epigallocatechin gallate (EGCG) acts synergistically with various ${\beta}-lactam$ antibiotics against MRSA. In particular, the epicatechin, epigallocatechin (EGC), EGCG and gallocatechin gallate from Korean green tea has antibacterial activity against MRSA clinical isolates and the combination of tea polyphenols and oxacillin was synergistic for all the clinical MRSA isolates.

• Journal of Veterinary Clinics
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• v.31 no.6
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• pp.502-506
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• 2014

Recently nano particles have proven for wide array of bioactive properties. In the present study, antibacterial properties of chitosan silver nano composites (CAgNCs) were investigated against fish pathogenic Edwardsiella tarda. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CAgNCs against E. tarda were $25{\mu}g/mL$ and $125{\mu}g/mL$, respectively. The field emission scanning electron microscope (FE-SEM) image of CAgNCs treated E. tarda showed the strongly damaged bacteria cells than non-treated bacteria. Furthermore, treatment of CAgNCs induced the level of intracellular reactive oxygen species (ROS) in E. tarda cells in concentration and time dependent manner suggesting that it may generate oxidative stress leading to bacterial cell death. In addition, MTT assay results showed that the lowest cell viability at $100{\mu}g/mL$ of CAgNCs treated E. tarda. Overall results of this study suggest that CAgNCs is a potential antibacterial agent to control pathogenic bacteria.