• The Korean Journal of Food And Nutrition
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• v.21 no.1
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• pp.15-21
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• 2008

In this study, the minimum inhibition concentration(MIC), growth inhibition activity, and colony forming inhibitory activity of water soluble propolis against Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, Streptococcus mutans, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae and Salmonella enteritidis were tested. The MICs of the water soluble propolis against Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, Streptococcus mutans, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, and Salmonella enteritidis were 312.5 ppm, below 156.3 ppm, 625 ppm, 10,000 ppm, above 10,000 ppm, 10,000 ppm, above 10,000 ppm, above 10,000 ppm, 10,000 ppm, and above 10,000 ppm, respectively. The growth inhibition concentrations against Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, Streptococcus mutans, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, and Klebsiella pneumoniae were 156.3 ppm, below 156.3 ppm, 625 ppm, 5,000 ppm, 10,000 ppm, 10,000 ppm, 10,000 ppm, 10,000 ppm, and 5,000 ppm, respectively. However, 10,000 ppm did not inhibit the growth of Salmonella enteritidis. Finally, the colony forming inhibitory activities against Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, Streptococcus mutans, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, and Salmonella enteritidis were 98.0%, 99.8%, 69.8%, 98.1%, 62.0%, 63.1%, 79.5%, 61.9%, 79.6%, and 0.0%, respectively.

• 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.

• Korean Journal of Food Science and Technology
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• v.39 no.5
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• pp.564-568
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• 2007

In this study, the ethanolic extracts of 40 species of traditional herbal medicines were examined for their antimicrobial activities against Clostridium difficile. Among the 43 screened traditional herbal medicines, Achyranthes Japonica Nakai (AJN), Siegesbeckia glabrescens Makino, and Phelloedendron amurense Ruprecht showed antimicrobial activities greater than 90% at a concentration of 500 ppm. According to the minimum inhibitory concentration (MIC) test the ethyl acetate soluble fraction of the AJN ethanolic extracts (AJNEA) showed the highest growth inhibitory activity against C. difficile, with a MIC of $625{\mu}g/mL$. In addition, the effect of AJNEA on the growth of lactic acid bacteria was investigated. AJNEA did not inhibit the growth of the tested Bifidobacterium spp. or Lactobacillus spp., with the exception of B. longum, Streptococcus thermophilus, and L. helveticus. These results indicate that AJNEA can be utilized as a potential antimicrobial agent against C. difficile related disease.

• Journal of the FoodService Safety
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• v.1 no.1
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• pp.27-35
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• 2020

Salt is a common seasoning agent used in various processed foods, especially in kimchi and salted seafood (jeotgal). This study was conducted to investigate the efficacy of salt with antimicrobial substances (acetic acid, garlic extract, carvacrol, nisin, thymol, and their combination (acetic acid+nisin+thymol)) on improvement of antibacterial effects of salt against foodborne pathogens. Salt (10%) was prepared using six different types of 0.2% natural antimicrobial substances. The antibacterial effect of salt combined with natural antimicrobial substances was evaluated against foodborne pathogens using the broth micro-dilution method and growth curve plotted using absorbance measurements. For the five foodborne pathogens, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of salt without antimicrobial substances as control were in the range of 24~>50,000 ㎍/mL and >50,000 ㎍/mL, respectively. Salt with nisin, thymol, or garlic extract showed strong inhibitory effects and their MIC against L. monocytogenes were 49, 12,500, and 24 ㎍/mL, respectively. In particular, salt with nisin showed inhibitory activities against Gram-positive bacteria. However, all the antimicrobial substances were less effective against Gram-negative bacteria such as E. coli O157:H7 and S. Typhimurium than Gram-positive bacteria. These results could be used for the development of salt with natural antimicrobial substances especially targeted against L. monocytogenes. This would enable the lowering of saline concentration while improving the storability of food.

• Journal of Pharmacopuncture
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• v.22 no.1
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• pp.49-54
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• 2019

Objective: Antibiotic resistance is a global health problem and threatens health of societies. These problems have led to a search for alternative approaches such as combination therapy. The aim of the present study was to investigate the effect of caffeine and omeprazole in combination with gentamicin or ciprofloxacin against standard and clinically resistant isolates of Staphylococcus aureus and Escherichia coli. Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interaction of non- antibiotic drugs with gentamicin and ciprofloxacin was studied in vitro using a checkerboard method and calculating fraction inhibitory concentration index (FICI). Verapamil as efflux pump inhibitor was used to evaluate the possible mechanism of bacterial resistance to antibiotics. Results: The MIC and MBC values of gentamicin against bacterial strains were in the range of $20-80{\mu}g/ml$ and $40-200{\mu}g/ml$, respectively. Caffeine and omeprazole had no intrinsic inhibitory activity against tested microorganisms. However, upon combination of caffeine with antibiotics, the synergistic effects were observed. Verapamil was able to reduce the MIC values of gentamicin (4 folds) only in some bacterial strains. Conclusion: These findings indicated that caffeine was effective in removing bacterial infection caused by S. aureus and E. coli. The relevant mechanisms of antibiotic resistance were not related to the drug efflux.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.232-238
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• 1998

To developed natural food preservatives, ethanol and water extracts were prepared from the defatted camellia(Camellia japonica L.) seeds. Antimicrobial activities were examined against 14 microorganisms which were food borne pathogens and/or food poisoning microorganisms and food-related bacteria and yeasts. Ethanol extract showed antimicrobial activities against several microorganisms tested, but not on lactic acid bactria. Especially, minimum inhibitory concentrations(MIC) for yeasts were as low as 1mg/ml. Water extract exhibited antimicrobial activities for the yeasts tested, but almost bacteria were not observed. The ethanol extract was fractionated in the order of hexane, chloroform, ethylaetate and butanol fractions to test antimicrobial activity. The strongest activity for the tested yeasts were found in the butanol fractions, but bacteria were chloroform fraction. Hansenula anomala treated with ethanol were observed by scanning electron micrograph, and the results exhibited morphological changes, including the irregularly contracted cell surface and expanded ellipsoidal shape.

• Journal of Food Hygiene and Safety
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• v.10 no.3
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• pp.139-145
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• 1995

In order to develop a natural food preservative, the root bark of Morus alba was extracted with several solvents, and then antimicrobial activity was investigated. The optimum extracting condition for the antimicrobial substance from the sample, minimum inhibitory concentration (MIC) of the extracted substance against microorganisms were also examined. The antimicrobial activity of the ethanol extract form the sample was stronger than those of the extracts by the other solvents such as water, methanol. ethyl acetate and acetone. The optimum extracting condition for antimicrobial substance from the sample was shaking extraction twice for 5 hours at room temperature in case of 7 times of absolute ethanol added to the crushed root bark of Morus alba. The ethanol extract from the root bark of Morus alba had strong B. cereus, L. monocytogenes and S. aureus. Especially, Bacillus species was the most susceptible to the extracted substance. The ethanol extract showed antimicrobial activity against Gram negative bacteria(MIC, 160~1600 ug/ml) and yeasts(MIC, 1600 ug/ml) such as C. albicans and S. acidifaeciens. The extract also showed growth inhibition against molds such as A. niger, A. parasiticus, A versicolar and T. viride.

• Korean journal of food and cookery science
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• v.26 no.6
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• pp.848-852
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• 2010

This study investigated the antibacterial activities of extracts and fractions of Sasa borealis against eight bacteria (Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, Psedomonas aerginosa, Salmonella choleraesuis, Serratia marcescens and Vibrio vulnificus) by broth dilution assay. Using survival curves, the kinetics of bacterial inactivation upon exposure to the extracts and fractions were followed for 24 h. In this same manner, MIC (minimum inhibitory concentration) values were determined by broth microdilution assay and then confirmed to be the extract concentrations that inhibited bacterial growth. Sasa borealis extracts showed antibacterial activities against all tested bacteria. In particular, all tested fractions of Sasa borealis had stronger activities than 70% ethanol extract. MIC of Sasa borealis extract was determined to be 5 mg/mL against Salmonella choleraesuis. All fractions of Sasa borealis extract had extremely strong antibacterial activities. MIC of fractions were determined to be 0.03~2.5 mg/mL. These results suggest that the extracts and fractions of Sasa borealis effectively inhibited bacterial growth and thus are useful as natural antibacterial agents.

• Korean journal of food and cookery science
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• v.30 no.3
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• pp.278-283
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• 2014

This study was investigated the antibacterial activities of Cirsium japonicum from extracts five regions(Chungnam, Gyeonggi, Gangwon, Jeju and Jeonnam) extract against six food-borne pathogenes(Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica and Vibrio vulnificus) using the broth dilution and agar diffusion method. At concentrations between 0 and $750{\mu}g/mL$ the extracts showed an antibacterial effect against all tested bacteria. The antibacterial activities of Cirsium japonicum from Jeju and Gangwon are stronger than others. The minimum inhibitory concentration(MIC) values against the six bacteria ranged from 93.75 to $750{\mu}g/mL$. In time killing assay(cell growth curves), the tested bacteria inactivated upon exposure to the extracts for 24h. At the 24h exposure to the extracts, all bacteria were inhibited to over 70% for growth. In particular, Bacillus subtilis, Salmonella enterica and Vibrio vulnificus conveyed an inhibition of growth to almost complete. It is anticipated that Cirsium japonicum extracts may have greater potential as natural food preservatives.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.80-85
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• 2008

This study was carried out to assess the antidermatophytic potential of the ethyl acetate(EtOAc) extract of the marine isolate of Aspergillus sp.. The fungus was isolated by serial dilution, and was identified Aspergillus sp.. The EtOAc extract of the fungus was examined to evaluate the antidermatophytic efficacy against the fungal pathogens infecting human skin using the disc diffusion and MIC(minimum inhibitory concentration) determination methods. The EtOAc extract($5{\mu}l\;disc^{-1}$) was considered to have the antidermatophytic activity based on the inhibition percentage of the mycelial growth of the fungi tested such as Trichophyton mentagrophytes KCTC 6085, Microsporum canis KCTC 6591, Microsporum canis KCTC 6348, Trichophyton rubrum KCTC 6352, Microsporum canis KCTC 6349 and Trichophyton mentagrophytes KCTC 6316. The percentage of the inhibition ranged from 54% to 81, and the MIC obtained was 62.5, 62.5, 250, 125, 125, and $125{\mu}g\;ml^{-1}$, respectively. The extract had a strong detrimental effect on the spore germination of the tested skin infectious pathogens. These findings strongly support the role of the ethyl acetate extract as a potential antidermatophytic agent.