• Journal of Korean Society for Atmospheric Environment
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• v.29 no.2
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• pp.125-134
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• 2013

Various antimicrobial technologies have been developed to inactivate bioaerosols in indoor environments. In this study, air filter media were treated with a natural antibacterial agent of Sophora flavescens in order to inactivate the bacteria collected on the air filter. Three treatment methods were applied to manufacture the test antibacterial air filter media: electrospray, nebulization and dip-coating methods. In case of electrospray and nebulization processes, the size distribution of aerosolized natural antibacterial agent was measured using a scanning mobility particle sizer. Staphylococcus epidermidis bacteria were aerosolized to test inactivation of the filter media treated with a natural antibacterial agent. The pressure drop and the antibacterial efficiency of the filter media increased with increasing the mass loading of natural antibacterial agent in each treatment method. The antibacterial efficiency per loaded antibacterial agent mass by the electrospray method was the highest and the filter treated by the dip-coating method was the lowest among three treatment methods.

• Journal of Dairy Science and Biotechnology
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• v.17 no.1
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• pp.11-15
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• 1999

The objective of this study was to extract and purity the antibacterial agent from the fermented milk with Lactobacillus helveticus CH-1. The extraction and purification of antibacterial agent from the Lb. helveticus fermented milk were carried out by methanol extraction, acetone extraction, Sephadex G-200 gel filteration and thin layer chromatography and the results were as followings. The antibacterial activity of methanol-acetone extraction showed antibacterial activity against test organisms, B. subtilis, E. coli, Pseu. fluorescens, Sal. typhimurium, Shi. flexneri, and Sta. aureus. Sephadex G-200 gel chromatography showed only antibacterial activity from 33 to 37th fractions of 60 fractions. The agent purified from TLC plate confirmed the antibacterial activity by the means of bioautography.

• Korean Journal of Materials Research
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• v.31 no.6
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• pp.367-374
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• 2021

This paper presents the characteristics of gentamicin-loaded into cetyl trimethyl ammonium intercalated montmorillonite (GtM/CTMA/Mt) as a hybrid composite for a slow-released antibacterial delivery systems. The work describes the successful immobilization of gentamicin into the interlayers of surfactant-modified montmorillonite. Physicochemical characterization of the material is carried out by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The kinetics of the gentamicin release is investigated by in vitro study and analyzed based on UV-Vis spectrometry. In addition, antibacterial study is performed towards Klebsiella pneumoniae Staphylococcus aureus, Escherichia coli, and Streptococcus pyogenes. The results show that the gentamicin loading into CTMA/Mt increases the effectiveness of the antibacterial activity, as shown by the higher inhibition zone for all tested bacteria, compared to gentamicin as a positive control. The kinetics study suggests that the gentamicin release obeys the modified Korsmeyer-Peppas model. The physicochemical study and activity test demonstrate the feasibility of the GtM/CTMA/Mt for practical applications.

• International Journal of Industrial Entomology and Biomaterials
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• v.24 no.1
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• pp.37-40
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• 2012

The apidaecins are highly active against Gram-negative bacteria. Here, we show the expression and antibacterial activity of the bumblebee, Bombus ignitus, apidaecin. We PCR-amplified 51 bp of the active domain sequence of the B. ignitus apidaecin gene and expressed the recombinant B. ignitus apidaecin active domain in baculovirus-infected insect cells. The recombinant B. ignitus apidaecin active domain shows bactericidal activity against Gram-negative bacteria, including Pseudomonas tolaasii, a serious pathogen in cultivated mushrooms, but not Gram-positive bacteria. This result suggests that the active domain of the B. ignitus apidaecin is a potential antibacterial agent for the control of bacterial brown blotch diseases.

• Journal of Microbiology and Biotechnology
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• v.19 no.2
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• pp.204-207
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• 2009

We investigated novel antibacterial and synergistic activities of isocryptomerin isolated from Selaginella tamariscina. Isocryptomerin showed potent antibacterial activity against Gram-positive and Gram-negative bacterial strains including clinical isolates of antibiotic-resistant species such as methicillin-resistant Staphylococcus aureus(MRSA). Additionally, we further investigated the synergistic activity of isocryptomerin with a conventional antibiotic against MRSA. The result indicated that isocryptomerin had considerable synergistic activity in combination with cefotaxime. In summary, the present study suggests that isocryptomerin may have potential as a novel therapeutic agent for treatment of infectious diseases by not only human pathogenic bacteria but also multidrug-resistant bacteria.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.501-505
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• 2010

1-Acetyl-$\beta$-carboline was isolated as an anti-MRSA agent from the fermentation broth of a marine actinomycete isolated from marine sediment. The producing strain was identified to be Streptomyces sp. by phylogenetic analysis of the 16S rRNA gene sequence. The anti-MRSA agent was isolated by bioactivity-guided fractionation of the culture extract by solvent partitioning, ODS open flash chromatography, and purification with a reversed-phase HPLC. Its structure was elucidated by extensive 2D NMR and mass spectral analyses. Combination of 1-acetyl-$\beta$-carboline with ampicillin exhibited synergistic antibacterial activity against MRSA.

• Korean Journal of Pharmacognosy
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• v.41 no.1
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• pp.38-42
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• 2010

Curcumin content of butanol fraction from C. longa was found to be 22.4942% of the highest content. However, in DPPH radical scavenging ability and antibacterial activity against methicillin resistance Staphylococcus aureus(MRSA, CCARM3696), ethylacetate fraction contained 2.5791% of curcumin was exhibited highest activity. In comparison of enhancing antibiotic(ampicillin) effect against MRSA, ethanol extract contained 1.7838% of curcumin showed more strong activity. This indicates that the ethanol extract and some fractions from C. longa can have antibacterial activity and enhancing antibiotic effect possibly without curcumin. Appropriate use of antimicrobial agent was important point prior to the development of new antibiotics. And in that sence, extract and fractions of C. longa were worth using as synergist of antibiotics and natural antimicrobial agent.

• Journal of Technologic Dentistry
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• v.24 no.1
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• pp.43-49
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• 2002

To develop the natural antibacterial agents which don't have any toxicity against man, collected several species of medicinal plants were tested for their antibacterial activity from dental caries bacteria Streptococcus sanguis. The result of using paper disc method and the result of viable cell counting method, Phellodendri Cortex was selected as antibacterial agent. The high antibacterial activity was acquired at high extraction temperature and long extraction temperature. The antibacterial of Phellodendri Cortex was not effected by the concentration of ethanol.

• YAKHAK HOEJI
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• v.43 no.3
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• pp.342-350
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• 1999

The antibacterial activity against Propionibacterium acnes (P. acnes), $5{\alpha}-reductase$ inhibition and comedolytic effects are the important pharmacological target sites of antiacne drughs. We previously reported on the antibacterial activities against P. acnes by natural products. In the present study the screening of $5{\alpha}-reductase$ inhibition and comedolytic effects from natural products were performed. Seven natural products such as Angelica koreana, Sophora flavescens, Prunus persica, Bombyx mori, Areca catechu, Galla rhois and Gleditschia koraiensis perfectly inhibited the activity of $5{\alpha}-reductase$ at the concentration of 0.01% (w/v). Sixteen natural products which were shown to have the potent antibacterial activities against P.acnes or $5{\alpha}-reductase$ inhibition activities were assayed for the comedolytic test. In the results of comedolytic effects on experimentally-induced comedones (EIC), Sophora flavescens showed the strongest comedolytic effect on EIC, and Polygonum cuspidatum and Angelica koreana showed stronger comedolytic effects on EIC than azelaic acid used for a positive control at the concentration of 3% (w/v). These results suggest that several natural products including Sophora flavescens can be developed as noble antiacne agents.

• Journal of Life Science
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• v.10 no.1
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• pp.45-47
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• 2000

Nonactin, known as an ionophore antibiotic, was antagonized by the actibity of quercetin, an oxygen radical scavenger. This compound generated superoxide radicals in Bacillus subtilis lysates. A recombination-deficient mutant strain of B. subtilis was more sensitive than a wild strain, and this hypersensitivity was reduced in the presence of dithiothreitol as an antioxidant. These results suggest that superoxide radical is important in the antibacterial action of this agent.