• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.26-35
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• 2001

In order to search potent antifungal substances from domestic plants, 40 plants cultivated in Korea were collected. After extracting with methanol (MeOH) and concentrating to dryness, the MeOH extracts were screened for in vivo antifungal activity against six plant diseases at a concentration of $2000{\mu}g/mL$. Fourteen extracts showed disease-controlling activity more than 90% against at least one of the 6 plant diseases tested; eight, seven, and three extracts controlled more than 90% the development of rice blast, tomato late blight, and wheat leaf rust, respectively. However, none of the extracts exhibited in vivo antifungal activity more than 90% against rice sheath blight, tomato gray mold, and barley powdery mildew. From the MeOH extracts of Angelica gigas and A. dahurica showing potent controlling activity against rice blast, 1 and 2 antifungal substances, respectively, were isolated by solvent partitioning and column chromatography. The three compounds were identified to be coumarins, namely, decursin, imperatorin, and isoimperatorin, by mass spectrometry and NMR spectroscopy. They were examined for in vitro and in vivo antifungal activities together with umbelliferone (7-bydroxycournarin) and scopoletin (6-methoxy-7-hydroxycoumarin) containing a free hydroxyl group at position 7 to investigate the structure-activity relationship. In vitro, most of 50% growth inhibitory concentrations ($IC_{50}$) were over $200{\mu}g/mL$, indicating that they have relatively weak antifungal activity. The antifungal activity of decursin and scopoletin, containing cyclic alkoxy groups instead of free hydroxyl group at position 7, was stronger than umbelliferone and scopoletin. Especially, decursin and imperatorin showed potent antifungal activities against Pythium ultimum and Magnaporthe grisea, respectively, with $IC_{50}$ values less than $25{\mu}g/mL$. In vivo, decursin and imperatorin showed potent antifungal activity against rice blast, whereas other coumarins hardly controlled the development of 6 plant diseases tested. These results suggest that the antifungal activity of 7-hydroxycoumarin derivative is substantially increased when the hydroxyl group at position 7 is protected by a stable cyclic alkoxy grouping.

• Food Science and Preservation
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• v.11 no.2
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• pp.207-213
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• 2004

Methanol extracts were prepared from 32 medicinal herbs of the extracts were tested their microbial inhibition activities against food borne pathogens and/or food poisoning microorganisms, food-related bacteria and yeast. Methanol extracts of Cinnamomum cassia, Paeonia suffruticosa, Alnus japonica, Eugenio caryophyllata and Illicium verum exhibited antimicrobial activity for the microorganisms tested, except lactic acid bacteria and yeast. Minimum inhibitory concentrations(MIC) were about 5 mg/mL for Bacillus subtilis, Staphylococcus epidermidis and Pseudomonas aeruginosa. Cell growth of lactic acid bacteria was inhibitied, but greatly on Leuconostoc mesenteroides. The phenolic compound contents were 10.98 mg/g, 10.31 mg/g, 8.55 mg/g and 6.69 mg/g in Thea sinensis, Eugenia caryophyllata, Alnus japonica and Artenisia capillaris, respectively. Antimicrobial activity appeared to be related to phenol compound content in medicinal herbs. The methanol extracts of medicinal herbs could be suitable for the development of a food preservative.

• Food Science and Preservation
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• v.15 no.6
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• pp.878-883
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• 2008

Prunus mume was extracted using various solvents including ethyl ether, ethyl acetate and n-butanol. The extracts were fractionated by column chromatography. Antimicrobial compounds (A, B and C) in fractions showing antimicrobial activity were purified by Sephadex LH 20 column chromatography, and identified by $^{1}H$- and $^{13}C$-NMR analysis as isoeugenol, nomilin and $\beta$-sitosterol, respectively.

• KSBB Journal
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• v.15 no.6
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• pp.594-599
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• 2000

The adsorption of the antimicrobial agents and their heat-resistance were investigated for the packaging film manufacture, wherein, the antimicrobial agents were adsorbed on a ceramic component. The naturally sourced antimicrobial agents were produced by methylotropic actinomycetes strains MO-16 and MO-17, extracted with ethylacetate. Antimicrobial action was stable to $121^{\circ}C$ and 1 atm. for 30 min., showing wide-ranging activity to the Gram(+) and the Gram(-) bacteria. Antimicrobial agents, adsorbed on ceramic Ce-1, retained activity to the Gram(+) and the Gram(-) species at $105^{\circ}C$ and $230^{\circ}C$ heat treatment, and methanol extracted antimicrobial agents from Ce-1 treated at $230^{\circ}C$ for 30min., retained activity to Gram(+) bacteria. In the presence of oxygen during the heat treatment process, antimicrobial agents adsorbed on ceramic Ce-1 showed antimicrobial activity to Gram(+) and the Gram(-) bacteria.

• Journal of Dairy Science and Biotechnology
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• v.24 no.1
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• pp.19-28
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• 2006

This study was conducted to isolate antilisterial strains of the Bifidobacterium isolates from the infant feces. The bifidobacteria were isolated anaerobically on BL agar and screened for their inhibitory activity on the MRS-cysteine medium against three foodborne pathogens: Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus. Among the 52 bifidobacterial isolates, 5 strains(A24, Bl, B6, B10, and Bl2) were finally selected based on their stronger antilisterial activity against Listeria monocytogenes than other isolates tested. Morphologically, all the isolates were typically shown Y-and V-shaped under electron microscopic examination. Each isolate was primarily subjected to identification by a polymerase chain reaction(PCR) using a genus-specific primer designed for targeting the 16S rRNA gene sequence, and confirmed the primary identification data using an API-kit(Biomeriuex, France), commercially available product for identification based on biochemical and physiological traits. Of the isolates with antilisterial activity, strain A24 was finally confirmed as the Bifidobacterium longum A24.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.89-96
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• 2001

Three isoflavones and one isoflavanone were isolated from the wood of Sophora japonica (Leguminosae) which has been selected due to its high antifungal activity among the tested species, Four compounds were identified as 5,7-dihydroxy-4',6-dimethoxyisoflavone (irisolidone), 5,7-dihydroxy-4'-methoxyisoflavone (biochanin A), 7-hydroxy-4'-methoxyisoflavone (formononetin) and 7-hydroxy-4'-methoxy-isoflavanone by Mass and NMR spectroscopic analysis. The antifungal activity of the isoflavonoids was tested by medium dilution method and showed low antifungal activity indicating that the other compounds may contribute to high activity of the wood extractives of S. japonica.

• Journal of Life Science
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• v.29 no.1
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• pp.84-89
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• 2019

Previous screening of novel antibacterial agents revealed that some bacterial isolates exhibited antibiotic activity against both gram-positive and gram-negative bacteria and that they showed antibacterial activity, even against methicillin-resistant Staphylococcus aureus (MRSA). Among these isolates, one bacterial strain, BCNU 1204, was identified as Pseudomonas aeruginosa using phenetic and phylogenetic analysis, based on 16S ribosomal RNA gene sequences. The maximum productivities of antimicrobial substances of BCNU 1204 were obtained after being cultured at $35^{\circ}C$ and pH 7.0 for 4 d in King's medium B (KMB). Dichloromethane (DCM) and ethylacetate (EA) extracts of P. aeruginosa BCNU 1204 exhibited strong antimicrobial activity, particularly against gram-positive bacteria. The EA extracts exhibited broad-spectrum activity against antibiotic resistant strains. Fraction 5-2, was obtained by recycling preparative liquid chromatography (LC) and preparative thin-layer chromatography (TLC) and was identified as phenazine-1-carboxylic acid belonging to phenazines using gas chromatography and mass spectrometry (GC/MS). Its minimum inhibitory concentration (MIC) values were $25{\mu}g/ml$, $50{\mu}g/ml$, ${\geq}25{\mu}g/ml$, and ${\geq}50{\mu}g/ml$ for MRSA CCARM 3089, 3090, 3091, and 3095 strains, respectively. P. aeruginosa BCNU 1204 may be a potential resource for the development of anti-MRSA antibiotics. Additional research is required to identify the active substance from P. aeruginosa BCNU 1204.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.119-127
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• 2013

Twenty-three strains of Leuconostoc species and 45 strains of Weissella species inhibiting the growth of Lactobacillus sakei, one of the most populous lactic acid bacteria in over-ripened kimchi, were isolated from kimchi in our previous study. Among these hetero-fermentative 68 strains, Leuconostoc mesenteroides CK0128, Weissella cibaria CK0633, and W. cibaria KK0797 exhibited a relatively high survival rate in MRS medium, which was adjusted to pH 4.3 using an acid mixture consisting of acetic and lactic acids, and produced a large amount of exopolysaccharides. The culture supernatants of 3 strains were fractionated by a molecular weight cutter and lyophilized. The fractions with a molecular weight smaller than 3,000 Da showed antagonistic activity against Staphylococcus aureus and Lb. sakei. The anti-bacterial substances were very stable to heat treatments ($121^{\circ}C$, 15 min) and active at acidic conditions below pH 5. ${\alpha}$-Amylase, lipase, and proteolytic enzymes (proteinase K and pepsin) did not affect their activities. These non-proteinaceous anti-bacterial substances inhibited the growth of several food pathogens.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.213-214
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• 2001

일반적으로 척추동물 및 무척추동물들은 세균 및 기생충 등과 같은 외부물질의 침입으로부터 자신을 방어하기 위해 항균성 펩타이드를 생산하는 비특이적 면역체계를 가지고 있다고 알려져 있다. 최근까지 비특이적 면역기능을 수행하는 많은 항균성 펩타이드들이 포유류, 양서류 곤충, 및 식물 로부터 분리 정제되었고 구조 활성간의 연구가 활발히 진행되고 있으며 이러한 구조와 활성간의 연구는 거의 육상생물로부터 유래한 항균성 펩타이드에 한정되었고 해양생물, 특히 어류를 이용한 연구는 매우 미흡한 실정이다. (중략)

• Journal of Life Science
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• v.14 no.3
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• pp.411-416
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• 2004

In this study, we investigated the biological activity of antioxidant and antimicrobiological effect of Chondria crassicaulis (CC), which, using methanol, dichlolometane and ethanol, were extracted and fractionated into four different types: hexane(CCMH), methanol (CCMM), butanol (CCMB), and aqueous (CCMA) partition layers. The reducing activity on the 1,I-diphenyl-2-picrylhydrazyl (DPPH) radical and $O^{2-}$ and $O_{2}$$O_{2}$radical scavenging potential, in search for antioxidation effects of CC partition layer, were sequentially screened. Among the four fractions, CCMM had the highest antioxidative activity. The antimicrobial activity was increased in proportion to its concentration by the paper disc method. Among the various solvent layers, the CCMB, CCMH and CCMM showed relatively strong antimicrobial activities in the order.