• Restorative Dentistry and Endodontics
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• v.32 no.2
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• pp.102-110
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• 2007

The purpose of this study was to obtain the basic information for the improvement of dental environment by investigating the presence of methicillin- or vancomycin-resistant Staphylococcus aureus (MRSA or VRSA) isolated from dental health care workers (DHCWs) and environment of the Chosun University Dental Hospital (CUDH) and a private dental clinic (control group). Staphylococcus aureus (S. aureus) was isolated from anterior nares of 42 DHCWS and 38 sites, unit chairss, x-ray devices, computers, etc., at 10 departments of the CUDH and 20 DHCWs and 11 sites at the private dental clinic. S. aureus was isolated on mannitol salt agar plate and confirmed by PCR with S. aureus species-specific primer. Antimicrobial susceptibility test of clinical isolates of S. aureus against several antibiotics including methicillin (oxacillin) was performed by investigating minimum inhibitory concentration (MIC) using broth microdilution assay. In addition, PCR was performed to detect the methicillin- or vancomycin-resistant gene. The data showed that one strain of S. aureus was isolated from DHCWs of the CUDH and three strains of S. aureus was isolated from 3 samples of the private dental clinic, respectively. All of the isolates from the CUDH and the private dental clinic had resistance to penicillin G, amoxicillin and vancomycin and susceptibility to oxacillin and ciprofloxacin. The S. aureus strains were already obtained the resistance to penicillin G and amoxicillin. These results suggest that two dental clinics were under relatively safe environment.

• Journal of Food Hygiene and Safety
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• v.29 no.4
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• pp.376-382
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• 2014

Various solvents (chloroform, hexane, ethyl acetate, ethanol, methanol, and hot water) were tested to investigate the antimicrobial activities of sword bean (Canavalia gladiata) against 12 food poisoning bacteria. Chloroform, hexane, ethyl acetate and hot water extracts had no antimicrobial activities, but ethanol extract showed V. parahemolyticus 10 mm, S. sonnei 9 mm, and methanol extract showed strong activities in order of V. parahemolyticus 22 mm, S. sonnei 21 mm, L. monocytogenes 20 mm by disk diffusion. The minimal inhibitory concentrations (MICs) were also determined. The methanol extract had MIC values of 50 mg/mL against S. Typhimurium, V. parahemolyticus, and S. sonnei and values of 100 mg/mL against other 7 food poisoning bacteria and values of 200 mg/mL against Y. enterocolitica and MRSA. The inhibitory effect of methanol sword bean extract on the growth of V. parahemolyticus was investigated. Growth of the strain occurred at the concentration of 0.5% extract and was inhibited continuously at 1.0 and 1.5% for 30hours after inoculation, whereas the strain was completely inhibited at 2.0% after 9hours of inoculation.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.382-390
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• 2020

This study was carried out to evaluate the antimicrobial effect of red ginseng (Panax ginseng C.A. Meyer) against several foodborne pathogens including Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus niger. The antimicrobial effect was determined by agar diffusion method using red ginseng extract, crude saponin and non-water-soluble fractions. Red ginseng extract showed antimicrobial effect against S. aureus, but not C. albicans or A. niger. The extract showed anti-bacterial activity at concentration above 30% against S. aureus, which cause both food poisoning and atophic dermatitis. Crude saponin showed antibacterial activity above 7.5% against the bacterium. However, the ginsenosides purified from crude saponin showed no antimicrobial activities at 100-200 ㎍/mL. To investigate the mode of growth inhibition, red ginseng extract and crude saponin were added to 0.85% NaCl solution containing S. aureus and then incubated at 35℃ for 12 h. The results showed that viable cells were rapidly reduced in above 10% concentration of red ginseng extract and above 2% of crude saponin, respectively. However, the crude saponin and red ginseng extract did not inhibit the bacterial cells completely at those same concentrations. On the other hand, whereas all non-water-soluble fractions showed inhibition zones above 10 mm against S. aureus, they showed no inhibition effects against E. coli, C. albicans or A. niger. The methanol fraction-1 (MF-1) showed the highest antibacterial activity against S. aureus, and the MIC (minimal inhibitory concentration) was 0.625 mg/mL. These results suggest that red ginseng extract, crude saponin and non-water-soluble fractions show selective antibacterial activity against S. aureus, and non-water-soluble fractions might be used as natural antibacterial agents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.47-55
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• 2011

The solvent extracts of Aruncus dioicus var. kamtschaticus Hara, which were extracted by using several solvents with different polarities, were performed to investigate the antioxidant activities, whitening effect and antimicrobial activity. The content of total polyphenol of fractions from Aruncus dioicus var. kamtschaticus Hara extract showed the highest value ($335.88{\pm}2.26$ mg/g GAE) on ethyl acetate fraction. The ethyl acetate and n-butanol fractions were 0.06 mg/mL and 0.25 mg/mL as $IC_{50}$ values on DPPH radical scavenging, and $99.16{\pm}0.09%$ and $89.29{\pm}0.64%$ on ABTS radical scavenging activity, respectively. Also, reducing power and FRAP value were significantly higher on ethyl acetate fraction. The SOD like activity showed $80.76{\pm}0.61%$ on ethyl acetate and $72.34{\pm}0.79%$ on n-butanol. Tyrosinase inhibition activities (at 5 mg/mL) were $59.08{\pm}0.98%$ on ethyl acetate fraction. The chloroform fraction showed the strongest antimicrobial activities against B. cereus (14 mm), B. subtilis (12.5 mm), S. aureus (10.8 mm), E. coli (20.7 mm) at 0.1 mg/disc and the inhibition zone diameter of ethyl acetate fraction was 17.2 mm against E. coli at 0.5 mg/disc. The minimum inhibitory concentrations (MIC) of chloroform fraction against B. cereus and E. coli were 50 and $25{\mu}g$/mL, respectively. From these results, it is suggested that ethyl acetate and n-butanol fractions of Aruncus dioicus var. kamtschaticus Hara could be used as functional material for food additive ingredient and chloroform fraction could be suitable for the development of a food preservative.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.2 no.2
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• pp.139-146
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• 1999

Purpose: The aim of this study was to evaluate the clinical significance of 24 hour pH monitoring in the pediatric patients with recurrent vomiting or regurgitation. Methods: We performed 24 hour pH monitoring on 87 pediatric patients with recurrent vomiting or regurgitation using GastrograpH with glass electrode. The pathologic GER was determined by the reflux index (RI). RIs>10% were considered positive in patients <1 year of age, whereas RIs of >5% were positive in other age groups. We evaluated the mean and standard deviation of the reflux parameters between physiologic and pathologic GER groups, and also compared the reflux indices of each group with respect to time zones of the day. Results: Pathologic GER was found in 32 of 87 patients (36.8%), and the age incidence included 32.5% in infants <6 months old, 13.3% in infants aged 6 months-1 year old, 61.5% in children aged 1~2 years old, 14.3% in children aged 2~3 years old and 66.7% in children >3 years old. In physiologic GER patients, the RI was $3.7{\pm}2.9%$ for the patients <1 year old (group A), and $1.8{\pm}1.5%$ for those ${\geq}1$ year old (group B) which was statistically significant between the 2 age groups (p=0.02). The number of long refluxes more than 5 minutes was significantly increased (p=0.03) in group A ($1.7{\pm}1.9$) than in group B ($0.8{\pm}1.0$). The duration of the longest reflux was significantly longer (p=0.007) in group A ($604{\pm}551$ sec) than in group B ($275{\pm}296$ sec). In pathologic GER patients, the RI was $17.7{\pm}11.6%$ for the patients <1 year old and $7.8{\pm}2.9$ for those ${\geq}1$ year old. The number of long refluxes of more than 5 minutes were $8.9{\pm}4.6$ and $3.2{\pm}1.8$, and the duration of the longest reflux were $1955{\pm}2190$ sec and $1093{\pm}706$ sec for each age group. In both physiologic and pathologic GER patients, there was no significant difference of RI among the time zones of the day. Conclusion: Pathologic GER was found in 36.8% of patients. There was significant difference of RI between those <1 year old and those ${\geq}1$ year old in physiologic GER patients. There was no significant difference of RI among the time zones of the day in both pathologic and physiologic groups. In our study, the frequency of pathplogic GER was too much higher in age group of 1~2 years old (61.5%) than in group of 6 months-1 year old (13.3%), which means that further study is needed to determine the pathologic criteria of RI (Vandenplas criteria is >5%) in the age group of 1~2 years old.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1745-1752
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• 2010

This study was conducted to investigate the antimicrobial activity of 70% ethanol (EtOH) extract and the five fractions of the crude extract from Sasa borealis leaves against seven food poisoning bacteria, Staphylococcus aureus, Micrococus luteus, Listeria monocytogens, Bacillus subtilis, Escherichia coli, Salmonella Typhimurium, and Pseudomonas aeruginosa. The yield of 70% EtOH extract was 11.4% and those of n-hexane, chloroform, ethyl acetate, n-butanol, and aqueous fractions were 3.0%, 1.1%, 0.6%, 1.3%, and 5.1%, respectively. The 70% EtOH extract and the four fractions except aqueous fraction demonstrated antimicrobial activity against all the seven food poisoning bacteria at a concentration of 0.5%, although it was less compared to benzoic acid. Minimal inhibitory concentration (MIC) of the 70% EtOH extract against all the food poisoning bacteria except S. aureus was $50{\mu}L$/disc. Moreover, chloroform fraction was $35{\mu}L$/disc against 3 food poisoning bacteria and $50{\mu}L$/disc against the other 4 food poisoning bacteria; ethyl acetate fraction was $50{\mu}L$/disc against all the food poisoning bacteria. In addition, n-butanol fraction was $50{\mu}L$/disc against all the food poisoning bacteria except S. aureus. Aqueous fraction, which did not show antimicrobial activity at 5%, was $200{\mu}L$/disc against only S. aureus and L. monocytogen. The 0.25%, and 0.5% of ethyl acetate fraction inhibited the growth of all the food poisoning bacteria 8 to 12 hours and 24 hours, respectively. These results indicate that the Sasa borealis leaves may be useful as a natural antimicrobial substance.

• Journal of Oral Medicine and Pain
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• v.32 no.2
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• pp.137-150
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• 2007

Trees emit phytoncide into atmosphere to protect them from predation. Phytoncide from different trees has its own unique fragrance that is referred to as forest bath. Phytoncide, which is essential oil of trees, has microbicidal, insecticidal, acaricidal, and deodorizing effect. The present study was performed to examine the effect of phytoncide on Porphyromonas gingivalis, which is one of the most important causative agents of periodontitis and halitosis. P. gingivalis 2561 was incubated with or without phytoncide extracted from Hinoki (Chamaecyparis obtusa Sieb. et Zucc.; Japanese cypress) and then changes were observed in its cell viability, antibiotic sensitivity, morphology, and biochemical/molecular biological pattern. The results were as follows: 1. The phytoncide appeared to have a strong antibacterial effect on P. gingivalis. MIC of phytoncide for the bacterium was determined to be 0.008%. The antibacterial effect was attributed to bactericidal activity against P. gingivalis. It almost completely suppressed the bacterial cell viability (>99.9%) at the concentration of 0.01%, which is the MBC for the bacterium. 2. The phytoncide failed to enhance the bacterial susceptibility to ampicillin, cefotaxime, penicillin, and tetracycline but did increase the susceptibility to amoxicillin. 3. Numbers of electron dense granules, ghost cell, and vesicles increased with increasing concentration of the phytoncide, 4. RT-PCR analysis revealed that expression of superoxide dismutase was increased in the bacterium incubated with the phytoncide. 5. No distinct difference in protein profile between the bacterium incubated with or without the phytoncide was observed as determined by SDS-PAGE and immunoblot. Overall results suggest that the phytoncide is a strong antibacterial agent that has a bactericidal action against P. gingivalis. The phytoncide does not seem to affect much the profile of the major outer membrane proteins but interferes with antioxidant activity of the bacterium. Along with this, yet unknown mechanism may cause changes in cell morphology and eventually cell death.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.361-373
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• 2015

This study was carried out to evaluate the antioxidant and antibacterial activities of Glycyrriza uralensis Fisher (Jecheon, Korea) extracts obtained by various extraction conditions (85% ethanol, heating temperatures and times), and to establish the optimal extraction condition of G. uralensis for the application as cosmetic ingredients. The extracts obtained under different conditions were concentrated and made in the powdered (sample-1) and were the crude extract solutions without concentration (sample-2). The antioxidant effects were determined by free radical scavenging activity ($FSC_{50}$), ROS scavenging activity ($OSC_{50}$), and cellular protective effects. Antibacterial activity was determined by minimum inhibitory concentration (MIC) on human skin flora. DPPH free radical scavenging activity of sample-1 ($100{\mu}g/mL$) was 10% higher in group extracted for 6 h than 12 h, but sample-2 didn't show any significant differences. The extraction yield extracted with same temperature for 12 h was 2.6 times higher than 6 h, but total flavonoid content was 1.1 times higher. These results indicated that total flavonoid content hardly increased with increasing extraction time. Free radical scavenging activity, ROS scavenging activity and cellular protective effects were not dependent on the yield of extraction, but total flavonoid content of extraction. Antibacterial activity on three skin flora (S. aureus, B. subtilis, P. acnes)of sample-1 in different extraction conditions were evaluated on same concentration, and the group extracted at 25 and $40^{\circ}C$ showed 16 times higher than methyl paraben ($2,500{\mu}g/mL$). In conclusion, 85% ethanol extracts of G. uralensis extracted at $40^{\circ}C$ for 6 h showed the highest antioxidant and antibacterial activity. These results indicate that the extraction condition is important to be optimized by comprehensive evaluation of extraction yield with various conditions, yield of active component, and activity test with concentrations, and activity of 100% extract, for manufacturing process of products.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.673-680
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• 2009

This study was conducted to screen for plant food materials that improve human intestinal microflora, especially microorganisms associated with obesity. Among 30 tested plant food materials, the extract of Schizandra chinensis inactivated Eubacterium limosum, Bacteroides fragilis and Clostridium spp. Additionally, S. chinensis extract was also found to have a growth-promoting effect on Bifidobacterium spp.. The antimicrobial activity and antioxidant activity of the water extract did not decrease in respond to heating. Additionally, the water extract of S. chinensis did not show a toxic effect on the growth of Caco-2 cells. In vivo feeding tests were performed to investigate the influence of extract on the intestinal microflora in rats. Although the extract did not reduce obesity induced by a high fat diet, it led to significant increase in the population of Bifidobacterium spp. and a decrease in the population of Clostridium spp. in rats. Taken together, these results indicate that S. chinensis could be useful as a functional food component to control intestinal microbial flora.

• Tuberculosis and Respiratory Diseases
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• v.66 no.3
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• pp.178-185
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• 2009

Background: Epigallocatechin-3-gallate (EGCG) is the major catechin in green tea, and has shown antiproliferative, antiangiogenic, antimetastatic and cell cycle pertubation activity in various tumor models. Hypoxia can be induced because angiogenesis is insufficient for highly proliferating cancer. Hypoxia-inducible factor-1$\alpha$ (HIF-1$\alpha$) and its downstream target, vascular endothelial growth factor (VEGF), are important for angiogenesis, tumor growth and metastasis. The aim of this study was to determine how hypoxia could cause changes in the cellular phenomena and microenvironment in a non-small cell culture system and to examine the effects of EGCG on a HIF-1$\alpha$ and VEGF in A549 cell line. Methods: A549 cells, a non-small cell lung cancer cell line, were cultured with DMEM and 10% fetal bovine serum. A decrease in oxygen tension was induced using a hypoxia microchamber and a $CO_2-N_2$ gas mixture. Gas analysis and a MTT assay were performed. The A549 cells were treated with EGCG (0, 12.5, 25, 50 ${\mu}mol/L$), and then examined by real-time-PCR analysis of HIF-1$\alpha$, VEGF, and $\beta$-actin mRNA. Results: Hypoxia reduced the proliferation of A549 cells from normoxic conditions. EGCG inhibited HIF-1$\alpha$ transcription in A549 cells in a dose-dependent manner. Compared to HIF-1$\alpha$, VEGF was not inhibited by EGCG. Conclusion: HIF-1$\alpha$ can be inhibited by EGCG. This suggests that targeting HIF-1$\alpha$ with a EGCG treatment may have therapeutic potential in non-small cell lung cancers.