• Natural Product Sciences
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• v.17 no.2
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• pp.160-164
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• 2011

The purpose of this investigation was to extract the bioactive agents from Alpinia officinarum Hance. The methanol with ethylacetate extracts alone and combined were examined for their activities against VRE (vancomycin-resistant enterococci) and pathogenic yeast in vitro. The incidence of infections caused by VRE and other pathogenic microorganisms and the importance of using novel synergistic drug combinations has become important. Previously, we reported the antimicrobial effects of the butanol extract from Lonicera japonica and have evaluated combinations of solvent extracts, with a focus on the MeOH and EtOAc extracts from A. officinarum. In the present study, enhanced inhibitory effects were achieved by employing a combination of the two solvent extracts. The MeOH and EtOAc combination was especially effective against four VRE strains: E. faecalis (K-10-22), E. faecaium (K-11-212), E. faecalis (K-10-57) and E. faecalis (K-10-361) with MIC values of 12.5, 12.5, 6.25 and 25 ${\mu}g/ml$, respectively. Thus, the combination was more effective than other antibiotics such as kanamycin, gentamicin or tetracycline against bacteria including E. coli, Staphylococcus aureus, and Micrococcus luteus. In addition, the combination was effective against yeasts such as Candida albicans, Candida tropicalis and Cryptococcus neoformans.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.6
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• pp.886-893
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• 2012

Methicillin-Resistant Staphylococcus aureus (MRSA) is a cephalosporin and beta-lactam antibiotic-resistant strain. In most cases, MRSA is spread from infected patients and infection rates are growing increasingly. Furthermore, increased resistance to antibiotics is causing serious problems in the world. Staphylococcus aureus is responsible for both nosocomial and community-based infections that range from relatively minor skin and soft tissue infections to life-threatening systemic infections. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. In this study, we investigated antimicrobial activity of oriental medicine prescription against MRSA. The minimum inhibitory concentration (MIC) of Sohamhyung-tang water extract against S. aureus strains ranged from 500 to 2,000 ${\mu}g/mL$, so we have it confirmed that a strong antibacterial effect. Also, the combinations of Sohamhyung-tang water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Sohamhyung-tang water extract against MRSA have antibacterial activity, it has potential as alternatives to antibiotic agent. We suggest that the Sohamhyung-tang water extract lead the treatment of bacterial infection to solve the resistance and remaining side-effect problems that are the major weak points of traditional antibiotics.

• Macromolecular Research
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• v.16 no.4
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• pp.303-307
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• 2008

A series of biodegradable polymeric scaffolds was prepared by using a combination of natural (collagen) and synthetic (poly(caprolactone)) (PCL) polymers in various compositions. These scaffolds were soft, spongy, porous and transparent in nature and were characterized by thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. The entrapment efficiency and drug release activity of the scaffolds were analyzed using penicillin and tetracycline as antimicrobial drugs. The drug release activity of the scaffolds with various combinations of collagen and PCL were studied by measuring the optical density in a spectrophotometer at the following time intervals: 1,4, 24, 48 and 60 h. These scaffolds showed better and continuous drug release for up to 60 h. Even after such a long duration, a portion of the drug remained entrapped in the scaffolds, indicating that they can be utilized for wound healing applications.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.189-196
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• 2021

Periplanetasin-2 from cockroach exhibits broad-spectrum antimicrobial activity. The underlying antibacterial mechanisms rely on the stimulation of reactive oxygen species overproduction to induce apoptotic cell death. A promising strategy to increase the bioavailability of periplanetasin-2 involves reducing the dose through combination therapy with other antibacterials that show synergistic effects. Thus, the synergistic antibacterial activity of periplanetasin-2 with conventional antibacterial agents and its mechanisms was examined against Escherichia coli in this study. Among the agents tested, the combinations of periplanetasin-2 with vancomycin and chloramphenicol exhibited synergistic effects. Periplanetasin-2 in combination with vancomycin and chloramphenicol demonstrated antibacterial activity through the intracellular oxidative stress response. The combination with vancomycin resulted in the enhancement of bacterial apoptosis-like death, whereas the combination with chloramphenicol enhanced oxidative stress damage. These synergistic interactions of periplanetasin-2 can help broaden the spectrum of conventional antibiotics. The combination of antimicrobial peptides and conventional antibiotics is proposed as a novel perspective on treatments to combat severe bacterial infection.

• Journal of Pharmacopuncture
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• v.19 no.4
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• pp.312-318
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• 2016

Objectives: Bacterial resistant infections have become a global health challenge and threaten the society's health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus) and the standard strain of Pseudomonas aeruginosa (P. aeruginosa). Methods: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI). Results: The MICs of gentamicin against bacterial strains were in the range of $0.312-320{\mu}g/mL$. The MIC values of both types of catechins were $62.5-250{\mu}g/mL$. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1). A combination of caffeine with gentamicin did not alter the MIC values of gentamicin. Conclusion: The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains. Therefore, combinations of gentamicin with these natural compounds might be a promising approach to combat microbial resistance.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1026-1034
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• 2016

In the current study, a total of 135 enterococci strains from different sources were screened for the presence of the enterocin-encoding genes entA, entP, entB, entL50A, and entL50B. The enterocin genes were present at different frequencies, with entA occurring the most frequently, followed by entP and entB; entL50A and L50B were not detected. The occurrence of single enterocin genes was higher than the occurrence of multiple enterocin gene combinations. The 80 isolates that harbor at least one enterocin-encoding gene (denoted "Gene⁺ strains") were screened for antimicrobial activity. A total of 82.5% of the Gene⁺ strains inhibited at least one of the indicator strains, and the isolates harboring multiple enterocin-encoding genes inhibited a larger number of indicator strains than isolates harboring a single gene. The indicator strains that exhibited growth inhibition included Listeria innocua strain CLIP 12612 (ATCC BAA-680), Listeria monocytogenes strain CDC 4555, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, S. aureus ATCC 29213, S. aureus ATCC 6538, Salmonella enteritidis ATCC 13076, Salmonella typhimurium strain UK-1 (ATCC 68169), and Escherichia coli BAC 49LT ETEC. Inhibition due to either bacteriophage lysis or cytolysin activity was excluded. The growth inhibition of antilisterial Gene⁺ strains was further tested under different culture conditions. Among the culture media formulations, the MRS agar medium supplemented with 2% (w/v) yeast extract was the best solidified medium for enterocin production. Our findings extend the current knowledge of enterocin-producing enterococci, which may have potential applications as biopreservatives in the food industry due to their capability of controlling food spoilage pathogens.

• Food Science of Animal Resources
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• v.41 no.4
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• pp.608-622
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• 2021

Bioactive peptides have great potentials as nutraceutical and pharmaceutical agents that can improve human health. The objectives of this research were to produce functional peptides from ovotransferrin, a major egg white protein, using single enzyme treatments, and to analyze the properties of the hydrolysates produced. Lyophilized ovotransferrin was dissolved in distilled water at 20 mg/mL, treated with protease, elastase, papain, trypsin, or α-chymotrypsin at 1% (w/v) level of substrate, and incubated for 0-24 h at the optimal temperature of each enzyme (protease 55℃, papain 37℃, elastase 25℃, trypsin 37℃, α-chymotrypsin 37℃). The hydrolysates were tested for antioxidant, metal-chelating, and antimicrobial activities. Protease, papain, trypsin, and α-chymotrypsin hydrolyzed ovotransferrin relatively well after 3 h of incubation, but it took 24 h with elastase to reach a similar degree of hydrolysis. The hydrolysates obtained after 3 h of incubation with protease, papain, trypsin, α-chymotrypsin, and after 24 h with elastase were selected as the best products to analyze their functional properties. None of the hydrolysates exhibited antioxidant properties in the oil emulsion nor antimicrobial property at 20 mg/mL concentration. However, ovotransferrin with α-chymotrypsin and with elastase had higher Fe³⁺-chelating activities (1.06±0.88%, 1.25±0.24%) than the native ovotransferrin (0.46±0.60%). Overall, the results indicated that the single-enzyme treatments of ovotransferrin were not effective to produce peptides with antioxidant, antimicrobial, or Fe³⁺-chelating activity. Further research on the effects of enzyme combinations may be needed.

• The Korea Journal of Herbology
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• v.35 no.3
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• pp.47-54
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• 2020

Objective : Infectious diseases are a growing problem worldwide by Methicillin-resistant Staphylococcus aureus (MRSA). Daehwangmokdan-tang is one of the oriental medicine prescriptions contained in Principles and Practice of Eastern Medicine. This study investigated the antibacterial activity of EtOH 70% extracts of Daehwangmokdan-tang (DMT) which prescription is composed of oriental medicine against MRSA. Methods : The antimicrobial activity and active concentration of MRSA were verified by measuring the minimum inhibitory concentration (MIC) of DMT. In addition, the effects of the disease were checked by treating the existing antibiotics and large ethanol extract in parallel, and the extent of growth suppression was checked over time. In addition, cell membrane permeability experiment confirmed the effect of large DMT on the immunity mechanism of MRSA. Results : TThe minimum inhibitory concentration of DMT against MRSA is 500 ~ 2000 ㎍/㎖ by broth dilution method. In the checkerboard method, the combinations of DMT with antibiotics has partial synergistic effect or synergy effect and DMT markedly reduced the MICs of the antibiotics oxacillin (OX), gentamicin (GEN) against MRSA. In the inhibition of resistance mechanism of DMT against MRSA, the expression of resistance gene and protein about β-lactam antibiotic was reduced. Also, we observed the effect of DMT about cell membrane permeability against MRSA, and confirmed that DMT suppressed growth of strains by increasing cell membrane permeability and energy metabolism. Conclusion : Basis on the result, we speculate that DMT may be useful for the treatment of MRSA infections when used in combination with β-lactam antibiotic.

• Journal of Microbiology and Biotechnology
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• v.34 no.2
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• pp.314-329
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• 2024

Fifteen cyclic dipeptides (CDPs) containing proline, one cyclo(Phe-Ala) without proline, and a non-peptidyl ᴅⳑ-3-phenyllactic acid were previously identified in the culture filtrates of Lactobacillus plantarum LBP-K10, an isolate from kimchi. In this study, we used Japanese quail (Coturnix japonica) eggs to examine the effects of probiotic supplementation on the antimicrobial CDPs extracted from quail eggs (QE). Eggshell-free QE were obtained from two distinct groups of quails. The first group (K10N) comprised eggs from unsupplemented quails. The second group (K10S) comprised eggs from quails supplemented with Lb. plantarum LBP-K10. The QE samples were extracted using methylene chloride through a liquid-liquid extraction process. The resulting extract was fractionated into 16 parts using semi-preparative high-performance liquid chromatography. Two fractions, Q6 and Q9, were isolated from K10S and identified as cis-cyclo(ⳑ-Ser-ⳑ-Pro) and cis-cyclo(ⳑ-Leu-ⳑ-Pro). The Q9 fraction, containing cis-cyclo(ⳑ-Leu-ⳑ-Pro), has shown significant inhibitory properties against the proliferation of highly pathogenic multidrug-resistant bacteria, as well as human-specific and phytopathogenic fungi. Some of the ten combinations between the remaining fourteen unidentified fractions and two fractions, Q6 and Q9, containing cis-cyclo(ⳑ-Ser-ⳑ-Pro) and cis-cyclo(ⳑ-Leu-ⳑ-Pro) respectively, demonstrated a significant increase in activity against multidrug-resistant bacteria only when combined with Q9. The activity was 7.17 times higher compared to a single cis-cyclo(ⳑ-Leu-ⳑ-Pro). This study presents new findings on the efficacy of proline-containing CDPs in avian eggs. These CDPs provide antimicrobial properties when specific probiotics are supplemented.

• Korean Journal of Veterinary Research
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• v.37 no.2
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• pp.389-403
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• 1997

Survey on MIC of antimicrobial drugs and its treatment efficacy in mice were conducted for the strains of Escherichia coli and Salmonella spp isolated from feces of young domestic animals with diarrhea in 1996. A total of 338 strains of E coli and 61 strains of Salmonella spp were examined for the susceptibility to 20 antibiotics and 7 synthetic antimicrobial drugs. The results indicated that the majority of strains were susceptible to amikacin(93.5%), cefoperazone/sulbactam(93.5%), cefotaxim(93.3%), cefomandole(92.8%), cefoperazone(91.6%) and ciprofloxacin(85.1%), in order. Although gentamicin, ciprofloxacin and norfloxacin showed the relatively low MIC distributions, erythromycin, doxycycline, sulfamethoxazole and oxytetracycline revealed the high MIC distributions to most of isolates. The $MIC_{90}$ of antimicrobials for E coli were > $62.5{\mu}g/ml$ in gentamicin, $2.0{\mu}g/ml$ in ciprofloxacin, $1.0{\mu}g/ml$ in norfloxacin, > $500{\mu}g/ml$ in erythromycin, $125{\mu}g/ml$ in doxycycline, > $1000{\mu}g/ml$ in sulfamethoxazole and > $250{\mu}/ml$ in oxytetracycline. In general, the MIC of E coli isolates was higher than that of Salmonella spp isolates. Although variation in synergism or additivity of antibiotic combinations were demonstrated, ampicillin-gentamicin was the most efficacious combination both against E coli and Salmonella spp with the fluctuation of 7.7-77.5%. In the experiment of treatment efficacy in mice, the highest survival ratio(83.3%) after challenge with pathogenic E coli and Salmonella typhimurium was detected in the group treated with gentamicin.