• The Plant Pathology Journal
• /
• v.26 no.1
• /
• pp.57-62
• /
• 2010

Low-molecular-weight secondary metabolites from plants play an important role in reproductive processes and in the defense against environmental stresses or pathogens. In the present study, we isolated various volatiles and phenolic compounds from white Rosa rugosa flowers, and evaluated the pharmaceutical activities of these natural products in addition to their ability to increase survival in response to environmental stress and pathogen invasion. The DPPH and hydroxyl radical-mediated oxidation assay revealed that the white rose flower extract (WRFE) strongly scavenged free radicals in a dose dependent manner. Moreover, WRFE inhibited the growth of E. coli and fatally attacked those cells at higher concentration (>0.5 mg/mL). FITC-conjugated Annexin V stain provided further evidence that WRFE had strong antimicrobial activity, which may have resulted from a cooperative synergism between volatiles (e.g. 1-butanol, dodecyl acrylate and cyclododecane) and phenolic compounds (e.g. gallic acid) retained in WRFE. In conclusion, secondary metabolites from white rose flower hold promise as a potential natural source for antimicrobial and non-chemical based antioxidant agents.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.2
• /
• pp.243-249
• /
• 2001

This study was investigated to determine the antimicrobial effect of the ethanol extract of Quercus mongolica leaf on microbial growth. The ethanol extract at the concentration of $250\;\mu\textrm{g}/mL\;and\;500\;\mu\textrm{g}/mL$ inhibited the growth of gram positive and gram negative food-borne disease bacteria for 40 hours in tryptic soy broth, respectively. Antimicrobial activity of the ethanol extract from Quercus mongolica leaf was not affected by pH and heat treatment. The comparision between ethanol extract and commercially available preservatives on antimicrobial activity in food system was conducted. When the 0.1% ethanol extract of Quercus mongolica leaf was added to pine needle drink and carrot juice, antimicrobial activity was similar to those of containing 0.05% benzoic acid and 0.5% grapefruit seed extract. Also addition of 2~3% ethanol extract to the soybean paste inhibited the microbial growth up to 7 week, comparable to the inhibition of 2% ethanol. Thus, this results indicate that the ethanol extract of Quercus mongolica leaf may be useful as natural antimicrobial agents.

• Journal of the Korean Applied Science and Technology
• /
• v.37 no.2
• /
• pp.279-286
• /
• 2020

Natural extracts were isolated from 20 kinds of medicinal plants that have been traditionally widely used in Korea to develop treatments for dental caries. Medicinal plants showing antibacterial activity against a cariogenic bacterium, Streptococcus sobrinus KCOM 1157 were investigated. The natural extracts of Glycyrrhiza uralensis, Sophora flavescens, Coptis Chinensis, Mentha arvensis, Pinus densiflora, Spirodela polyrhiza showed antimicrobial activities against S. sobrinus KCOM 1157. The extracts of Pinus densiflora, Sophora flavescens, Coptis Chinensis among these medical herbs showed significant antimicrobial activity. These results suggested that the natural products of Pinus densiflora, Sophora flavescens, Coptis Chinensis could be the potential source of anticariogenic agent against dental pathogens including S. sobrinus.

• Archives of Pharmacal Research
• /
• v.21 no.3
• /
• pp.278-285
• /
• 1998

The microdilution assay recommended by NCCLS (National Committee for Clinical Laboratory Standards) is one of the standardized methods of antibiotic susceptibility test. This method has been widely used clinically to obtain MIC values of antibiotics on pathogenic microorganisms. It is more convenient, rapid and simple to test many samples than other test methods such as agar diffusion assay and broth macrodilution assay. The screening of antimicrobial agents from microbial extracts is too laborious in its process. Therefore, a number of screening methods having more simple procedure have been developed. In our laboratory, we applied microdilution assay for screening the antimicrobial agents. This assay showed dose-response results and was more sensitive than disc diffusion assay in our system. We tested 200 samples of microbial extracts originated from 100 microbial strains and selected several samples as potential candidates. In this report, we show that the microdilution assay is more convenient method in screeing of antibiotic susceptibility than those previously reported.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.11
• /
• pp.1457-1466
• /
• 2012

Antimicrobial peptides (AMPs) exert antimicrobial activity against Gram-positive and Gram-negative bacteria, fungi, and viruses by various mechanisms. AMPs commonly possess particular characteristics by harboring cationic and amphipathic structures and binding to cell membranes, resulting in the leakage of essential cell contents by forming pores or disturbing lipid organization. These membrane disruptive mechanisms of AMPs are possible to explain according to the various structure forming pores in the membrane. Some AMPs inhibit DNA and/or RNA synthesis as well as apoptosis induction by reactive oxygen species (ROS) accumulation and mitochondrial dysfunction. Specifically, mitochondria play a major role in the apoptotic pathway. During apoptosis induced by AMPs, cells undergo cytochrome c release, caspase activation, phosphatidylserine externalization, plasma or mitochondrial membrane depolarization, DNA and nuclei damage, cell shrinkage, apoptotic body formation, and membrane blebbing. Even AMPs, which have been reported to exert membrane-active mechanisms, induce apoptosis in yeast. These phenomena were also discovered in tumor cells treated with AMPs. The apoptosis mechanism of AMPs is available for various therapeutics such as antibiotics for antibiotic-resistant pathogens that resist to the membrane active mechanism, and antitumor agents with selectivity to tumor cells.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.12
• /
• pp.2075-2088
• /
• 2017

Salmonella is one of the principal causes of foodborne outbreaks. As traditional control methods have shown less efficacy against emerging Salmonella serotypes or antimicrobial-resistant Salmonella, new approaches have been attempted. The use of lytic phages for the biocontrol of Salmonella in the food industry has become an attractive method owing to the many advantages offered by the use of phages as biocontrol agents. Phages are natural alternatives to traditional antimicrobial agents; they have proven effective in the control of bacterial pathogens in the food industry, which has led to the development of different phage products. The treatment with specific phages in the food industry can prevent the decay of products and the spread of bacterial diseases, and ultimately promotes safe environments for animal and plant food production, processing, and handling. After an extensive investigation of the current literature, this review focuses predominantly on the efficacy of phages for the successful control of Salmonella spp. in foods. This review also addresses the current knowledge on the pathogenic characteristics of Salmonella, the prevalence of emerging Salmonella outbreaks, the isolation and characterization of Salmonella-specific phages, the effectiveness of Salmonella-specific phages as biocontrol agents, and the prospective use of Salmonella-specific phages in the food industry.

• Journal of Digital Convergence
• /
• v.16 no.6
• /
• pp.353-361
• /
• 2018

RFW and RFE of castor fruit selected as part of the development of natural antimicrobials and antioxidants yielded 15.8% and 18.4% respectively. In the results of measuring the antimicrobial activity through paper disc method, the antimicrobial activity of castor fruits in ethanol extracts appeared. Especially, the activity was excellent in P. aeruginosa and S. aureus, and antimicrobial activity of C. was 1.5mm up to 16 hours. However, the proliferation of C. was observed again after 24 hours. In the MIC experiment results of RFE, S. aureus and P. aeruginosa showed 96% and 93% of antimicrobial activity, respectively. The DPPH radical scavenging activity of RLW and castor leaf ethanol extract showed $1.8{\pm}0.6%$ and $2.1{\pm}0.7%$ free radical scavenging activity at $1000({\mu}g/m{\ell})$. This study is expected to provide basic data for the development of antimicrobial agents and antioxidants using natural products.

• Advances in Traditional Medicine
• /
• v.1 no.2
• /
• pp.45-51
• /
• 2000

This study was carried out to evaluate cytotoxicity of the methanol extract from Sophora flavescens Ait. against L1210 (lymphocytic leukemia) and $P388D_1$ (lymphoid neoplasma) Cells in vitro. We have determined cytotoxicity by the MTT (3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H- tetrazolium bromide) assay. The order of cytotoxicity of Sophora flavescens Ait. extracts against L1210 and $P388D_1$ cells in vitro is as follows: Fr. 4 > Fr. 3 > Fr. 5 > Fr. 2 > Fr. 1. These results suggest that the fraction 4 of the methanol extracts from Sophora flavescens Ait. may be a valuable choice for the development of antitumor agents. In order to develop an antimicrobial agent, dried Sophora flavescens Ait. was extracted with hot methanol, and then antimicrobial activity (MIC test) was investigated. In this study, the fraction 3 of the methanol extracts from the roots of S. flavescens showed strong growth inhibition activity against gram-positive and gram-negative bacteria (MIC, $3.125\;{\mu}g/ml$) such as S. mutans, S. epidermidis and P. putida. These results indicate that fractions 3 and 4 inhibit tumor cells and bacteria.

• Korean Journal of Veterinary Service
• /
• v.24 no.1
• /
• pp.51-68
• /
• 2001

The result of studying the epidemiological characteristics of Salmonella strains which have been isolated from the domestic animals in Gyeongbuk province from February 1998 to August 2000 were summarized as follows. The isolation rates of Salmonella strains were 2.0% from cattle feces, 6.3% from cattle lymph node, 9.5% from pig feces, and 25.1% from pig lymph node. In poultry, the isolation rates were 30.3%. The isolates of Salmonella showed positive reaction for MUCAP test, methyl red test, but showed negative reaction for urea test, indole test, Voges Proskauer test. On TSI agar, the isolates showed acid butt, alkaline slant. Also, the isolates were identified as Salmonella strain by API 20E kit. Non H$_2$S Production Salmonella strains isolated from poultry were identified as S gallinarum. As a result of serotyping, B group were the most common in cattle and pig, Dl in chickens. 21 serovars were found. the common serovar from the domestic animals was S typhimurium, S derby, S agona, S schwarzenground, S enteritidis and S gallinarum. The most commonly encountered serovars in cattle were S agona and S typhirimurium in pig, S gallinarum in chicken. As a result of antimicrobial susceptibility test, all Salmonella isolates were susceptible to amikacin, ciprofloxacin, norfloxacin; cefotaxime and polumcin B. The resistance rates to tetracycline and streptomycin was 58% and 56%, respectively. 69.3% of all isolates were resistant to more than one antimicrobial agent. Out of the resistant isolates, the isolates resistant to streptomycin and tetracycline was 36%. There were 24 strains of multiresistant isolates resistant to more than 5 antimicrobial agents. S typhimurium were resistant to all antimicrobial agents, also had a lot of multiresistant strains. Therefore, S typhimurium was considered as a major agent of antimicrobial resistance.

• Journal of Integrative Natural Science
• /
• v.4 no.1
• /
• pp.15-22
• /
• 2011

In this study, liquid with carbonized artemisia was developed for the first time that can be used as food additives and outside medicinal agents by burning artemisia species such as Artemisia dubia wall, Artemisia capillaris Thunb, Artemisia montana (Nakai) Pamp), Artemisia keiskeana Miq, Leonurus Japonicus Houtt. etc. In addition, edibility of recovered liquid with carbonized artemisia was verified by comparing the contents according to each ingredient with common refined pyroligneous liquid through the analysis of 9 kinds of organic acid by the species of artemisia, methanol and ethanol. Besides, the result of antimicrobial activities on six kinds of food spoilage and food poisoning bacteria observed by paper disc method for liquid with carbonized artemisia indicated that those two liquids showed strong antimicrobial. At the concentration of 1.5 mg/disc, clear zone for S. sonnei and S. aureus, L. monocytogenes was 13~16 mm, and they showed stronger antimicrobial activities than other strain.