• 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.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.161-165
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• 2012

Antimicrobial peptides of insects are found and reported as immune defence system against infectious agents. The peptides are produced by fat body cells and thrombocytoids, a blood cell type. Defensin is 38-45 amino acids long and consists of an ${\alpha}$-helix linked by a loop to an antiparallel ${\beta}$-sheet. Defensin from a bumblebee, Bombus ignitus, is known to comprise 52 amino acid residues. This peptide consists of two ${\alpha}$-helixes; ACAANCLSM and KTNFKDLWDKRF and one ${\beta}$-sheet; GGRCENGVCLCR. We carried out antibacterial activity test by radial diffusion assay against Staphylococcus aureus (Gram positive), Escherichia coli (Gram negative), Pseudomonas syringae (Gram negative), Candida albicans (fungi), MDRPA, MRSA, and VRE (antimicrobial resistant microbes) with synthetic oligopeptides from Peptron (Daejeon, Korea). The predicted curtailment fragment (GGRCEVCLCR-$NH_2$) for ${\beta}$-sheet had strong antibacterial activity when internal amino acids were removed. But, curtailment fragments (ACAANCLSM-$NH_2$ and TNFKDLWDKR-$NH_2$) of ${\alpha}$-helix were not showed antibacterial activity. These synthetic oligopeptides were showed the great activity against Gram positive and negative bacteria.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.75-79
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• 2022

Fresh, washed ginseng can be contaminated with microorganism loads as high as 6.5 log CFU/g for total bacteria and 4.3 log CFU/g for mold. The goal of this study was to test eight antibacterial agents on ginseng. Immersing fresh ginseng washed in 1% (w/w) sodium citrate, sodium diacetate, sodium acetate, citric acid, and sodium lactate solution for 1 h resulted in a bactericidal effect of 31.0-97.5% for total bacteria. Among the organic acids, sodium citrate had the best antibacterial effect, with total bacteria reduced from 6.5 log to 4.9 log CFU/g. A 1% (w/w) vitamin B₁ lauryl sulfate solution with surfactant function by hydrophilic and hydrophobic sites can reduce 2.7 log CFU/g (99.8% inactivation) on total bacteria. In the 1% (w/w) calcium oxide solution, total bacteria were reduced by 3 log, showing an excellent inactivation effect of 99.9%. Calcium oxide is a highly useful material for inactivation of microorganisms in fresh ginseng.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.610-616
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• 2002

The growth-inhibiting effects of Pinus densiflpora leaf-derived materials on nine human intestinal bacteria were investigated using the impregnated paper disk method, and their activities were compared with those of 13 commercially available terpenes. The biologically active constituent of the extract of P densiflora leaf was characterized as the monoterpene (1R)-(+)-$\alpha$-pinene by various spectroscopic analyses. Responses varied according to bacterial strain, chemicals, and dose. At 10 mg/disk, limonene and (1R)-(+)-$\alpha$-pinene strongly inhibited the growth of Clostridium perfringens, Staphylococcus aureus, and Escherichia coli, without adverse effects on the growth of five lactic acid-bacteria (Bifidobacterium adolescentis, B. bifidum, B. longum, Lactobacillus acidophilus, and L. casei). Little or no inhibition against seven bacteria was observed with anethole, borneol, camphor, caryophyllene, 1,8-cineole, estragole, linalool, and $\alpha$-terpineol. Structure-activity relationship revealed that (1R)-(+)-$\alpha$-pinene had more growth-inhibiting activity against C. perfringens than (1R)-(+)-$\beta$-, (1S-(-)-$\alpha$-, and (1S-(-)-$\beta$-pinenes. Furthermore, the growth-inhibition against L. casei was much more pronounced in (1R)-(+)-$\beta$- and (In-(-)-$\beta$-pinenes than (1R)-(+)-$\alpha$- and (1S)-(-)-$\alpha$-pinenes. These results indicate that the (+)-$\alpha$ form seems to be required against C. perfringens and $\beta$ form against L. casei for growth-inhibiting activity. Morphologically, most strains of C. perfringens were damaged and disappeared at 5 and 2 mg/disk of (1R)-(+)-$\alpha$-pinene. Morphological study revealed that (1R)-(+)-$\alpha$-pinene had more growth-inhibiting activity against C. perfringens than (1R)-(+)-$\beta$-, (1S)-(-)-$\alpha$-, and (1S)-(-)-$\beta$-pinenes. As naturally occurring growth-inhibiting agents, the Pinus leaf-derived materials described above could be useful preventive agents against diseases caused by harmful intestinal bacteria such as clostridia.

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.89-99
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• 1983

The rational approach to antimicrobial therapy of infected root canals is based on accurate identification of the infecting organism and on the organism's susceptibility to antimicrobial agents as measured by standardized techniques. In establishing criteria for the selection of antibiotics, a susceptibility test should be performed. The purpose of this study was to investigate the susceptibility of 224 aerobic and anaerobic microbial strains isolated from infected root canals to various antibiotics. This was performed by using 7 antibiotic sensi-disc: Penicillin (10 units), Ampicillin (10 mcg), Tetracycline (30 mcg), Streptomycin (10 mcg), Kanamycin (30 mcg), Lincomycin (2 mcg), and Clindamycin (2 mcg). The results were as follows; 1. Strains isolated from infected root canals was shown to be most susceptible to Clindamycin, while Streptomycin exhibited least antibacterial properties. 2. Anaerobes were found to be susceptible to Penicillin, Ampicillin, and Clindamycin. 3. Streptomycin and Kanamycin were shown to be effective against Staphylococcus aureus and Staphylococcus epidermis, however, unidentified G(+) cocci organisms were found to be resistant to these agents. 4. Bifidobacterium sp. was susceptible to Lincomycin while G(+) rods were resistant to it. 5. Staphylococcus aureus, Micrococcus sp., and anaerobes were highly susceptible to Clindamycin. 6. All of the antibiotics tested were shown to be very effective against Eubacterium sp.

• Korean Journal of Clinical Pharmacy
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• v.22 no.4
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• pp.291-303
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• 2012

As respiratory tract infections (RTI) account for about 60% of all antibiotic prescriptions in outpatient care setting, there are significant concerns about emerging resistance that are largely due to the excessive or inappropriate use of antibacterial agents for viral respiratory infections. This study was aimed to develop retrospective drug utilization review (DUR) program of antibiotics for RTIs using Delphi methods. Retrospective DUR criteria of antibiotics for RTIs were identified based on clinical practice guidelines and opinion of experts. Expert panel members were clinical doctors and pharmacists and Delphi method was applied by survey on 16 members of panels. The claim data from Korean Health Insurance Review & Assessment (HIRA) were used to examine trends in outpatient antibiotic prescription between Janunary to December of 2008. As results, Quality index for RTI was assessed for the claim type, antibiotics use of quantity, duration, number and cost. Antibiotic prescription rate for RTIs, Defined Daily Dose (DDD), and duration of antibiotics use were more recognized as significant quality index by experts' opinion. Use of first line agents suggested by guidelines was low and duration of antibiotics use was shorter compared to the recommendations. Antibiotics were over prescribed for RITs. However, dose and duration of antibiotics were under-used.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.59-65
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• 2006

Fluoroquinolones are the most common group of antibacterial agents currently used in the Korean aquaculture industry, and use of these agents has been increasing steadily. High performance liquid chromatography (HPLC) with fluorescence detection was used for the simultaneous determination of five fluoroquinolones in fish and shellfish: ofloxacin (OFL), pefloxacin (PEF), norfloxacin (NOR), ciprofloxacin (CIP), and enrofloxacin (ENRO). Fish and shellfish muscle was homogenized, and protein, lipid, and low molecular weight pigments were then excluded from the homogenate. The final eluates were analyzed by HPLC equipped with a Shiseido UG-120 type C18 reverse-phase column ($4.6{\times}250 mm$, $5{\mu}m$) and a fluorescence detector (excitation at 280 nm, emission at 450 nm). The mobile phase was 0.1 M phosphoric acid and acetonitrile solution (91:9, v/v) and tetrahydrofuran (THF) was added to it at a rate of 5 mL per a liter of the mobile phase. Adequate chromatography separation was obtained using the above method. Average recoveries of fortified samples at levels from 0.05 to 0.5 mg/kg were $72.3{\pm}2.5-84.5{\pm}1.2%$ for OFL, $82.7{\pm}3.3- 109.3{\pm}7.5%$ for NOR, $85.3{\pm}6.6-116.0{\pm}7.9%$ for PEF, $76.0{\pm}4.3-109.3{\pm}12.4%$ for CIP, and $78.7{\pm}5.9-100.0{\pm}9.8%$ for ENRO. The limit of detection of OFL was $5{\mu}g/L$, the others were $1{\mu}g/L$. We concluded that the new analytical method was suitable for the determination of fluoroquinolones in fish and shellfish.