• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.899-904
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• 2002

Aloe and propolis are extensively used in folk medicine. Ethanol extracts of Aloe vera (AE), ethanol extract of propolis (PE) and waxfree extract of propolis (PW) were prepared to test antimicrobial activities against five oral microorganisms (Streptococcus mutans, Enterococcus faecalis, Enteococcus hirae, Escherichia coli, Candida albicans). Antimicrobial activities were tested by serial broth dilution method and expressed by minimal inhibitory concentration (MIC). The AE showed relatively weak antimicrobial activities, while both of PE and PW greatly inhibited all microorganisms tested. To investigate the antimicrobial effects of the combined extracts of aloe with propolis, the fractional inhibitory concentration index (FICI) was determined by checkerboard assay for each strain. The combination of AE with PE or PW resulted in Synergistic effect against oral microorganisms tested (FICI=0.375) except Escherichia coli (FICI=1.0 for PE, FICI=0.75 for PW).

• Korean Journal of Pharmacognosy
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• v.53 no.2
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• pp.87-95
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• 2022

Methicillin resistance Staphylococcus aureus (MRSA) is a gram-positive bacterium, the most commonly isolated bacterial human pathogen. JiYu-san is one of the natural products used to treat diseases in the folk recipe. In this study, we investigated the antimicrobial activity of EtOH 70% extracts of JiYu-san (JYS) against MRSA. The antibacterial activity of JYS against MRSA strain was evaluated using minimum inhibitory concentration (MIC), checkerboard dilution test, and time-kill assay. The effect of JYS on the immune mechanism of MRSA was confirmed through cell membrane permeability tests and energy metabolism tests, and the antibacterial activity mechanism was performed using qRT-PCR and western blot. As a result, in the antibacterial test of JYS, the MIC was measured to be 1.9~1000 ㎍/mL, and synergistic or showed a partial synergistic effect. In addition, JYS showed antibacterial activity in a combination test with DCCD or TX-100. In a study on the mechanism of action of antibacterial activity, it was found that JYS suppressed MRSA resistance genes and proteins. These results suggest that JYS has antibacterial activity and provides great potential as a natural antibiotic by modulating the immune mechanism against MRSA.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.4
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• pp.390-395
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• 2014

Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria. monocytogenes and Bacillus cereus are pathogenic bacteria that should not be detected in cosmetics and foodstuffs. Therefore, we first investigated the antimicrobial activities of extracts of Scutellariae Radix(SR), Coptidis Rhizoma (CR) and salicylic acid(SA) in these pathogenic microorganisms. Although SA has been known to exhibit anti-inflammation and antimicrobial activity against pathogenic microorganisms, a high concentration of SA may cause serious side effects such as skin redness, skin burning, peeling or tissue damage. Hence, we focused on diminishing side effects followed by treatment of a high concentration of SA and investigated whether the combinations of SA with various concentrations(25-400 mg/mL), SR and CR with a concentration(100 mg/mL) which did not show antimicrobial activity against E. coli and P. aeruginosa exhibited meaningful antimicrobial effect against both strains. In our results, the combinations of SA with the lowest concentration(25 mg/mL), SR(100 mg/mL) and CR(100 mg/mL) exhibited significant antimicrobial activity against E.coli in comparison to SA alone(25 mg/mL) showing no antimicrobial activity. Moreover, the combinations of SA (100 mg/mL), SR and CR showed seven times higher antimicrobial activity against E. coli than SA alone(100 mg/mL) and exhibited a significant antimicrobial activity in comparison to ampicilin (p<0.05). The combinations of SA(100 mg/mL), SR and CR showed two times higher antimicrobial activity against P. aeruginosa than SA alone. Therefore, these results indicated that the combinations of SR, CR and SA with low concentration expressed the synergistic antimicrobial effect against E. coli and P. aeruginosa and showed great potential as an antimicrobial agent.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2043-2050
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• 2016

Exploring novel antibiotics is necessary for multidrug-resistant pathogenic bacteria. Because the probiotics in soybean food have antimicrobial activities, we investigated their effects on multidrug-resistant Acinetobacter baumannii. Nineteen multidrug-resistant A. baumannii strains were clinically isolated as an experimental group and 11 multidrug-sensitive strains as controls. The growth rates of all bacteria were determined by using the analysis for xCELLigence Real-Time Cell. The combination of antibiotics showed synergistic effects on the strains in the control group but no effect on the strains in the experimental group. Efflux pump gene adeS was absent in all the strains from the control group, whereas it exists in all the strains from the experimental group. Furthermore, all the strains lost multidrug resistance when an adeS inhibitor was used. One strain of probiotics isolated from soybean food showed high antimicrobial activity for multidrug-resistant A. baumannii. The isolated strain belongs to Bacillus subtilis according to 16S RNA analysis. Furthermore, E. coli showed multidrug resistance when it was transformed with the adeS gene from A. baumannii whereas the resistant bacteria could be inhibited completely by isolated Bacillus subtilis. Thus, probiotics from soybean food provide potential antibiotics against multidrug-resistant pathogenic bacteria.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.518-523
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• 2011

The aim of this study was to evaluate the antimicrobial activities of leek and garlic extract juice and powder against Escherichia coli, Salmonella enteritidis, and Staphylococcus aureus in a single strain and a mixed strains system. Garlic juice and powder showed higher antimicrobial activity against Sta. aureus than that of E. coli or S. enteritidis. The antimicrobial activities of the leek and garlic powders decreased with increasing temperature and time, but stabilized at various pHs. The antimicrobial effects of mixtures of various ratios between the leek and garlic extracts increased with an increase in garlic extract content. No synergistic effects by the leek and garlic mixtures were observed. In a mixed strains system, the antimicrobial effects of leek and garlic powder were similar to those in a single strain system.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.277-281
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• 2004

This study was performed to investigate the antimicrobial effect of the Fraxinus rhynchophylla extracts against food-borne pathogens. First, the Fraxinus rhynchophylla was extracted with methanol at room temperatures, and fractionation of the methanol extracts from Fraxinus rhynchophylla was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol respectively. The antimicrobial activity of the Fraxinus rhynchophylla extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extracts of Fraxinus rhynchophylla showed the highest antimicrobial activity against Staphylococcus aureus and Shigella dysenteriae. The synergistic effect has been found in combined extracts of Fraxinus rhynchophylla and Portulaca aleracea as compared to each extracts alone. Finally, the growth inhibition curve was determined using ethyl acetate extracts of Fraxinus rhynchophylla against Staphylococcus aureus and Shigella dysenteriae. The ethyl acetate extract of Fraxinus rhynchophylla showed strong antimicrobial activity against Staphylococcus aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate extract from Fraxinus rhynchophylla retarded the growth of S. aureus more than 24 hours and Shigella dysenteriae up to 36 hours. The ethyl acetate extracts of Fraxinus rhynchophylla has been shown the antimicrobial effect against Staphylococcus aureus and Shigella dysenteriae.

• Korean Journal of Food Science and Technology
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• v.48 no.3
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• pp.241-246
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• 2016

The object of this study was to develop an alternative way to treat human skin pathogens using marine algae. During this study, we observed that the ethanolic extract of the edible brown algae [Sargassum serratifolium (C. Agardh) C. Agardh] exhibited potential antimicrobial activity against pathogenic commensal bacteria related with acne vulgaris (Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa), and Candida albicans which causes cutaneous candidiasis. Among the solvent-soluble fractions from the ethanolic extract, a hexane-soluble fraction showed the strongest antimicrobial activity against all tested human skin pathogens with MIC values ranging from 32 to $512{\mu}g/mL$. In addition, the hexane fraction exhibited a synergistic antimicrobial activity with commercial antibiotics used in the treatment of acne vulgaris or cutaneous candidiasis. Thus, this study suggests that S. serratifolium extract could be a potential source of natural antimicrobial agents or a pharmaceutical component against human skin pathogens.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.289-294
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• 2010

Salvia miltiorrhiza Bunge (S. miltiorrhiza) is a traditional Korean medicine that is commonly used for the treatment of inflammatory diseases such as edema, arthritis, and hepatitis. The present study investigated the antimicrobial activity of methanol (MeOH) extract of S. miltiorrhiza roots against oral bacteria using broth the microdilution method and the checkerboard and time-kill methods evaluated the synergistic effects of treatment with antibiotics. The MeOH extract was demonstrated as a higher antibacterial activity (MICs, 8 to $64\;{\mu}g/mL$; MBCs, 16 to $64\;{\mu}g/mL$) against all tested oral bacteria. Additionally, the extract was observed to have a synergistic effect with ampicillin or gentamicin. A time-kill study evaluating the effects of the extract indicated that the extract treatment in combination with ampicillin or gentamicin showed rapid bactericidal activity. The results suggest that MeOH extract of S. miltiorrhiza could be employed as a natural antibacterial agent against dental caries.

• International Journal of Oral Biology
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• v.43 no.4
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• pp.193-200
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• 2018

The purpose of this study is to determine if natural extracts could be used as an additive in oral health food made with Weissella cibaria CMU (oraCMU). Natural extracts of green tea, mulberry leaf, licorice, and propolis, which are reported to have antimicrobial activities, were selected and used in this study. The minimum inhibitory concentrations (MIC) of extracts on periodontal pathogens such as Fusobacterium nucleatum and Porphyromonas gingivalis and their synergy effects with oraCMU by the fractional inhibitory concentrations methods were measured. From the results obtained, all the extracts showed no effect on the growth of oraCMU. Green tea extract showed the best antibacterial activity with MIC of 1.8 mg/ml against both F. nucleatum and P. gingivalis. In addition, green tea extract had a synergistic effect with oraCMU against F. nucleatum. Therefore, these results suggested that green tea extract is available as an additive in oral health food made with oraCMU.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1106-1111
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• 2004

This study was performed to investigate the antimicrobial effect of the Indigofera kirilowii extracts against food-borne pathogens. The Indigofera kirilowii was extracted with methanol at room temperature, and fractionation of the methanol extract from Indigofera kirilowii was carried out by using petroleum ether, chloroform, ethyl acetate, and methanol, respectively. The antimicrobial activity of the Indigofera kirilowii extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extract of Indigo/era kirilowii showed the highest antimicrobial activity against Staphylococcus aureus and Shigella dysenteriae. The water extract of Indigofera kirilowii showed relatively low antimicrobial activity against microorganisms used in this experiment. The synergistic effect has been found in combined extracts of Indigofera kirilowii and Pulsatilla koreana as compared to each extract alone. The growth inhibition curve was determined using ethyl acetate extracts of Indigofera kirilowii against S. aureus and S. dysenteriae. The ethyl acetate extract of Indigofera kirilowii showed strong antimicrobial activity against S. aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate extract from Indigofera kirilowii retarded the growth of S. aureus more than 24 hours and S. dysenteriae up to 48 hours. This study showed the possibility of using ethyl acetate extract of Indigofera kirilowii as a material of food preservative.