• Journal of Veterinary Science
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• v.25 no.2
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• pp.30.1-30.16
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• 2024

Background: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. Objectives: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,O-carboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. Methods: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. Results: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis. In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. Conclusions: This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation.

• Journal of the Korean Society of Food Culture
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• v.39 no.3
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• pp.166-172
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• 2024

Human bitter taste-sensing type 2 receptors (hTAS2Rs) are expressed in various human tissues and may be associated with various cell signaling pathways, cell progression, and cell physiology in each tissue. hTAS2Rs can be a potential drug target because it is also expressed in some cancer cells. Xanthorrhizol (XNT) has various biological activities, such as anticancer, antimicrobial, anti-inflammatory, and antioxidant. XNT produces a bitter taste, but the specific hTAS2R activated is unknown, and the hTAS2R-mediated effect of XNT on cancer cells has not been studied. This study discovered the target receptor of XNT among 25 hTAS2Rs and confirmed the possibility of the hTAS2R-mediated inhibition of cancer cell proliferation. XNT activated only one receptor, hTAS2R38 (EC₅₀=1.606±0.021 ㎍/mL), and its activity was inhibited by probenecid, a hTAS2R38 antagonist. When HepG2 and MCF-7 cells were treated with XNT or phenylthiocarbamide (PTC), a known hTAS2R38 agonist, both chemicals inhibited cancer cell proliferation. XNT targets the human bitter taste receptor TAS2R38 and inhibits the proliferation of HepG2 and MCF-7 cells mediated by TAS2R38. This suggests that TAS2R38 may be a new target for disease treatment and a potential new factor for drug development.

• Natural Product Sciences
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• v.11 no.1
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• pp.27-32
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• 2005

The purpose of this study is to evaluate the inhibitory effects of Resina Pini against Streptococcus mutans (S. mutans) that is one of the major causes of dental caries and oral diseases. Topically applied Resina Pini (RP) would be incorporated in saliva and thus the factor associated with water solubility should be considered. In this paper, therefore, effects of various treatment for RP and activities of water extracts from unprocessed and processed RP were compared. The crude RP (RP1) and the recrystallized RP (RP2) in ethanol solution showed strong antimicrobial activities (d.>15mm) against S. mutans. All RP samples exhibited considerable inhibitory effect against glucosyltransferase produced by S. mutans $(IC_{50}=91.2\;to\;276.2\;{\mu}g/ml)$. The very considerable increase in cellular permeability of S. mutans was observed with RP1, RP2 and their water extracts. These results suggest that RP1 and RP2 may be a potential source for pharmaceutical products used for prevention and/or treatment of dental caries and periodontal disease.

• Journal of Microbiology and Biotechnology
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• v.26 no.1
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• pp.28-37
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• 2016

Numerous plants have been documented to contain phenolic compounds. Thymol is one among these phenolic compounds that possess a repertoire of pharmacological activities, including anti-inflammatory, anticancer, antioxidant, antibacterial, and antimicrobial effects. Despite of the plethora of affects elicited by thymol, its activity profile on gastric cancer cells is not explored. In this study, we discovered that thymol exerts anticancer effects by suppressing cell growth, inducing apoptosis, producing intracellular reactive oxygen species, depolarizing mitochondrial membrane potential, and activating the proapoptotic mitochondrial proteins Bax, cysteine aspartases (caspases), and poly ADP ribose polymerase in human gastric AGS cells. The outcomes of this study displayed that thymol, via an intrinsic mitochondrial pathway, was responsible for inducing apoptosis in gastric AGS cells. Hence, thymol might serve as a tentative agent in the future to treat cancer.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1106-1109
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• 2008

The anti-Helicobacter pylori activity, cytotoxicity, and anti-inflammatory activity of white ginseng extract (WGE) were investigated in vitro in this study. The antimicrobial effects of WGE toward H. pylori strains 52 J99, SSI, and 51 were tested using the disk diffusion method. Among these H. pylori strains, H. pylori 52 was the most sensitive, having the largest inhibition zone (19 mm), followed by J99, SSI, and 51. The zone of inhibition due to WGE increased significantly with increasing dosage. The cytotoxicity of WGE toward the human cancer cell lines A-549 (human lung carcinoma), HEC-1-B (human endometrial adenocarcinoma), HeLa (human uterin adenocarcinoma), and SW-156 (human kidney carcinoma) was measured using the 3-(4,5-dimethylthizol-2-yl)-2,5-diphenylate-tetrazolium bromide (MTT) assay. WGE exhibited an inhibitory effect on cell growth at 2.0 mg/mL for all tumor cell lines. An analysis of anti-inflammatory activity using the RAW 264.7 cell line showed that the inhibition of nitric oxide (NO) production increased as the WGE content increased. These results demonstrate the potential of WGE to be used as a health-promoting substance.

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.314-319
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• 2006

To determine the antimicrobial and anti-inflammatory efficacy of Opuntia ficus-indica for chronic otitis, we evaluated the effects of topical applications of the methanol extracts with 20 cases of dogs which had chronic malignant otitis by pathogens with antibiotic resistance. The dogs had revealed recurrent symptoms of malignant otitis and were not treated by conventional therapeutic agents. However, in this study, the clinical cure rates of Opuntia ficus-indica was 75% and the average alleviation period was $1.21{\pm}0.42$ week, and the mean recovery period was $1.06{\pm}1.06$ week after the initiation of treatment. As the results of this study, topical Opuntia ficus-indica extracts was found to be highly effective for the treatment of chronic malignant otitis with clinical cure rates of 75% within 1.06 weeks of therapy. Further evaluation of Opuntia ficus-indica extracts will allow us to establish and to optimize the therapeutic strategy for the malignant otitis in veterinary practice, and the potential usefulness of this complementary treatment on recurrent infectious pathology.

• Korean Journal of Veterinary Research
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• v.33 no.1
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• pp.61-69
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• 1993

In order to search for new antibiotics from anaerobic bacteria, a large number of samples from domestic soil were collected and processed by apropriate methods. A potential strain, Streptococcus sp. An-21-1, was found to produce antimicrobial compounds. The Results were as follows; 1. During fermentation, the bacteria grew rapidly up to 20hr, thereafter entered the death phase. The optimal temperature and pH for the bacterial growth were $37^{\circ}C$ and pH 7.0, respectively. 2. Antibiotics were purified from culture broth by solvent extraction, silica gel column chromatography and Sepadex L.H 20 column. 3. Physicochemical properties of Ap-1 and Ap-2 were similar ; Their melting points were between $234-237^{\circ}C$. Color reactions of ninhydrin, 2,7-dichlorofluorescein, 4-dimethylaminobenzaldehyde, Dragendroffs reagent and 20% $H_2SO_4$, were positive. Therefore, we assumed that these antibiotics have amine group, immine group, alkaloid, and lipid components. These were stable to heat. UV spectrophotometry showed two peaks at 210 nm and 260 nm. From above results, we assumed these antibiotics are belong to the peptide antibiotic family.

• Textile Coloration and Finishing
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• v.31 no.4
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• pp.341-353
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• 2019

Quercetin is one of flavonoids widely distributed in the plants and well known to have antioxidants, antiinflammatory, antimicrobial properties. In this study, alginate sponge containing quercetin-encapsulated nanocapsules was prepared by miniemulsion polymerization, dyring/crosslinking method and their bioactive characteristics were investigated. Alginate sponge containing quercetin-encapsulated nanocapsules were evaluated using a field emission scanning electron microscope(FE-SEM), a high performance liquid chromatography, cell viability, DPPH radical scavenging activity and antibacterial activity. The study indicates that alginate sponge containing quercetin-encapsulated nanocapsules had significant antioxidant, antiinflammatory and antibacterial activities. This study suggested that alginate sponge containing quercetin-encapsulated nanocapsules can be a potential candidate for medical materials.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.984-988
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• 2003

The actinomycete strain KH-6l4 possessed strong antifungal activity, especially antagonistic to the rice blast fungus, Pyricularia oryzae. Diaminopimelic acid (DAP) type and morphological and physiological characteristics, examined by scanning electron microscopy (SEM), indicated that KH-614 belonged to the genus Streptomyces. Antifungal agent produced by this strain was found to be most active, when the strain was cultured in the presence of glucose, polypeptone, and yeast extract (PY) medium for 6 days at $27^{\circ}C$. Based on the spectral report data, MS and NMR, the antifungal agent was identified as cyclo(L-leucyl-L-prolyl). According to the antimicrobial activity test measured by minimal inhibitory concentration (MIC), the cyclo(1eu-pro) exhibited the activity against Candida albicans IAM 4905, Mucor ramannianus IAM6218, Rhizoctonia solani IFO 6218, Aspergilus fumigatus ATCC 42202, Glomerella cingulata IFO 9767, Trichophton mentagrophytes ATCC 18749, and Trichophyton rubrum ATCC 44766, the order of MIC values were 50, 12.5, 5, 50, 25, 5, $5\;\mu\textrm{g}/ml$, respectively. Specifically, cyclo(1eu-pro) was one of the most effective elements against Pyricularia oryzae IFO 5994 with the MIC value of $2.5\;\mu\textrm{g}/ml$, thus indicating that cyclo(leu-pro) is a potential antifungal agent.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.161-168
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• 2010

In this study, the metabolic activities of five strains of Pediococcus spp., in terms of the quantities they produced of lactic acid, hydrogen peroxide, exopolysaccharides, and proteolytic activity, were determined. Lactic acid levels produced by these strains were found to be in the range of 2.5-5.6 mg/ml. All strains produced hydrogen peroxide. The P. pentosaceus Z13P strain produced the maximum amount (0.25 mg/ml) of proteolytic activity. Exopolysaccharide (EPS) production by the Pediococcus strains during growth in MRS (de Man, Rogosa, and Sharpe) medium was in the range 25-64 mg/l. The susceptibility of 10 different antibiotics against these strains was also tested. All strains were found to be resistant to amoxicillin, gentamicin, and vancomycin. Antimicrobial effects of the Pediococcus spp. on pathogens were also determined by an agar diffusion method. All of the strains were able to inhibit L. monocytogenes. The tolerance of the strains to low pH, their resistance to bile salts of strains, and their abilities to autoaggregate and coaggregate with L. monocytogenes were also evaluated.