• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.281-286
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• 2001

Since the number of amino groups which are exposed by deacetylation of acetyl-D-glucosamine influences antimicrobial activity, a chitosan oligosaccharide (COS) derivative by N-conjugation of COS with asparagine, an amino acid with two amino groups, was synthesized and the antimicrobial effect on E. coli growth was compared with other COS derivatives which were N-conjugated with glycine, alanine, aspartic acid, cysteins, an methionine, and unmodified COS. The structure of asparagine N-conjugated COS (Asn-COS) derivative was identified by using a FT-IR, $^{13}C\;FT-NMR$, and an elemental analyzer. The antimicrobial activity of Asn-COS against E. coli growth was significantly improved as compared to the other COS derivatives as well as COS itself. This means that Asn-COS with two positive charges strongly interacts with the carboxyl negative charges on the bacteria cell wall. The results for Asn-COS were as follows: 100% bactericidal activity, 0.002% MIC, and no growth of E. coli during 3 days of culture time, suggesting that Asn-COS may be useful as a new antibiotic agent.

• Korean Journal of Microbiology
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• v.42 no.1
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• pp.54-58
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• 2006

Dried roots of Paeonia japonica were extracted with dichloromethane, methanol and water aerially. Silica gel column chromatography and thin layer chromatography were used to separate the fractions with antimicrobial activities, and mass spectrometry was used to determine the mass. Dichloromethane extract showed the highest antimicrobial activity. Dichloromethane extract from Paeonia japonica could be a candidate for a new antimicrobial agent against MRSA.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.247-249
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• 2000

Antimicrobial activity of sophorolipid produced by Candida bombicola ATCC 22214 was investigated, Minimum inhibitory concentration of sophorolipid to Propionibacterium acne and Bacillus subtilis were 0.5 ppm and 4 ppm, respectively. However no antimicrobial activity to E. coli was detected. Indicating the antimicrobial activity of sophorolipid only toward gram positive bacteria. Antifungal activity of sophorolipid was also detected in the hyphae growth assay for Botrytis cinerea. Malate dehydrogenase, a cytoplasmic enzyme, of B. subtilis was remarkably increased with the sophorolipid treatment, indicating the leakage of membrane by sophorolipid. This result shows the potentials of sophorolipid as mild, non-toxic antimicrobial agent.

• The Korean Journal of Community Living Science
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• v.26 no.4
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• pp.697-705
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• 2015

This study investigates antimicrobial effects of food-borne pathogens and the antioxidant activity of Torreya nucifera extract. The growth of food-borne pathogens including Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans was inhibited by the extract. The antimicrobial activity of the extract was highest for Staphylococcus aureus among seven gram-positive bacteria and for Pseudomonas aeruginosa among six gram-negative bacteria. The extract exhibited slightly lower DPPH radical-scavenging activity, but its ABTS radical-scavenging activity was higher than that of ${\alpha}$-tocopherol. The results demonstrate the extract's antimicrobial effects on food-borne pathogens as well as potent antioxidant capacity and suggest that Torreya nucifera may be used as a natural antibacterial agent and an effective antioxidant in food.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.52-53
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• 2013

According to the increases the standard of living of the people, requirements for building environments are also being diversified. The fungus that occurred the building is not good the health of occupants as well as undermine the value of the building. However, chemical antimicrobial agent contain ingredients harmful to human body and it has an impact on indoor air quality. Therefore, the use of natural antimicrobial material is strongly required. In this study, the fungal reproductive inhibit capacity was evaluated by using mortars with natural antimicrobial material.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.17-22
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• 2004

Scutellaria baicalensis and Phellodendron amurense, which have been used traditionally in treatment of many kinds of illness including infectious diseases, were extracted with hexane, dichloromethane, methanol and water, respectively and serially. Antimicrobial activities of the extracts were examined by disk diffusion method. Methanol extract from Scutellaria baicalensis revealed high antimicrobial activities against MRSA, Gm-bacteria and Candida albicans, dichloromethnane extract from Phellodendron amurense showed lower activity than the extract of Scutellaria baicalensis. Results suggest that methanol extract from Scutellaria baicalensis could be one of the candidates for new antimicrobial agent against the antibiotic-resistant microorganisms by further steps for the purification, determination of structure and synthesis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.3
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• pp.755-759
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• 2007

In this study, we screened twenty four extracts of eight medicinal plants and three extracts of the commercial product for their antimicrobial and antioxidant properties. Ethanol and ethyl acetate extracts were found active where as aqueous extracts were little or no active. Extracts of Sophora flavescens, Salvia miltlorrhiza and Glycyrrhiza uralensis showed strong activity againsttested organisms and could be the potential antimicrobial agent. The increase of antimicrobial and antioxidant activities of formulations might be due to synergic effect. The results also indicated that the activity of bamboo salt and herbal products can be enhanced by making appropriate formulations.

• Biomedical Science Letters
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• v.30 no.1
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• pp.32-35
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• 2024

In vitro antimicrobial activities of hot water extracts of Chamaecyparis obtuse, for methicillin-resistant Staphylococcus aureus (MRSA) was compared to commonly used conventional antimicrobial agents. All MRSA was susceptible to linezolid or vancomycin, but also to erythromycin. MIC range and MIC₉₀ to erythromycin, clindamycin, levofloxacin, tetracycline for MRSA were each 4 ㎍/mL, 2 ~ >128 ㎍/mL, ≤0.06 ~ >128 ㎍/mL, 0.25 ~ >128 ㎍/mL, 0.25~64 ㎍/mL and 4 ㎍/mL, .128 ㎍/mL, >128 ㎍/mL, >128 ㎍/mL, 64 ㎍/mL. The hot water extracts of leaf of C. obtuse had the lowest MIC range, MIC₅₀, and MIC₉₀ (0.125 µL/mL) for the MRSA tested, and it was possible more potent than various conventional antimicrobial agents. Screen antibacterial drug candidate with high antibacterial activity such as derivatives of C. obtuse leaf extract such as terpinen-4-ol or using combined therapy with commercialized antibacterial agents will likely be helpful in treating refractory MRSA infections.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.251-257
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• 2009

Recently, there is much interest in the antimicrobial activity of silver since silver has known to be safe and effective as a disinfectant or an antimicrobial agent against a broad spectrum of microorganisms. Although silver has been applied to various kinds of products due to the effective antimicrobial activity, the quantitative antimicrobial activity or detailed mechanism of silver is not clearly investigated yet, causing the controversy and confusion. In this review paper, we summarized the characteristics, antimicrobial activities and mechanisms, synergistic effects with other antimicrobials, and applicability of silver.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.402-407
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• 2008

The synergistic antimicrobial effect of Achyranthes japonica Nakai (AJN) and Bifidobacterium extracellular factors against Clostridium difficile were measured using a turbidity method. Each broth supernatant of Bifidobacterium infantis ($68.8{\pm}0.02%$) and Bifidobacterium adolescentis ($33.2{\pm}0.2%$) obtained by adding ethyl acetate soluble fractionate from A. japonica Nakai ethanolic extracts (AJNEA, 100 ppm, no inhibition) showed high synergistic antimicrobial activity against C. difficile. In addition, the antimicrobial activity in a laboratory medium and yogurt products against C. difficile were evaluated. In yogurt prepared with a starter 5 (Lactobacillus acidophilus: Streptococcus thermophilus: B. adolescentis =1 : 1 : 1) and a starter 4 (L. acidophilus: S. thermophilus: B. infantis=1 : 1 : 1) and 0.5% AJNEA powder, high antimicrobial effects were recorded that measured 79.0 and 65.2%, respectively. The results indicated the potential of AJN extract for use as an antimicrobial agent. In addition, the efficiency of the antimicrobial activity of the extracts was further improved in combination with lactic acid bacteria, which suggests that they have the potential to be used as a highly effective antibiotic-tolerant microorganism prevention system. Such a strategy can be used for alternative drugs or functional food additives for treatment of antibiotic-associated diarrhea.