• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.162-166
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• 2002

Two bithiazole-type antibiotics were isolated from the culture broth of a Myxococcus species which isolated from the marine sediment off the coast of Cheju Island, Korea. The structures of these metabolites were determined as KR025 and melithiazole F, previously reported bithiazoles, using combined spectroscopic methods. Both compounds showed an antifungal activity. In in vivo tests, these compounds exhibited potent controlling activities against tomato late blight, wheat leaf rust, and barley powdery mildew with control values more than 80% at a concentraton of 20 $\mu\textrm{g}$/ml.

• Archives of Pharmacal Research
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• v.20 no.6
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• pp.586-589
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• 1997

Antifungal activities of 6-[(N-4-bromophenyl)amino]-7-chloro-5,8-quinolinedione (RCK7) were tested. The MIC values of RCK7 were determined for antifungal suceptibility, in vitro against Aspergillus niger, Cryptococcus neoformans and Trichophyton mentagrophyte by standard agar streak method. In vitro, RCK7 showed more potent antifungal activity than fluconazole and ketoconazole. Also, RCK7 was tested for in vivo antifungal activity in the treatment of systemic infection with Candida albicans in normal mice. The therapeutic potential of RCK7 had been assessed by evaluating their survival rate against systemic infections compared with that of ketoconazole. $ED_{50}$ of intraperitoneally administered RCK7 ws $2.05{\pm}0.30mg/kg$ but that of ketoconazole was $8.00{\pm}0.73 mg/kg$, respectively. When RCK7 was administered intravenously at the $ED_{50}$(2.05 mg/kg). the colony counts of Candida albicans in the liver after 7 days and 14 days were reduced as likely as ketoconazole at the $ED_{50}(8.00 mg/kg)$, and the better survival rates than ketoconazole's were achieved after 14 days. The results suggest that RCK7 may be a potent antifungal agent.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.37-44
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• 1999

Two sulphamide (dichlofluanid and tolylfluanid) and three dicarboximide fungicides (iprodione, vinclozolin, procymidone) were used to investigate the correlation between in vitro antifungal activities and in vivo disease controlling activities against Botrytis cinerea, a causal agent of tomato gray mold and to develop efficient in vitro assays. They controlled effectively the development of tomato gray mold disease in vivo and their controlling activities were similar one another. However, several in vitro assays revealed that their in vitro antifungal activities were quite different between sulphamide and dicarboximide fungicides; the formers showed stronger inhibition activities for spore germination than the latters, whereas the formers inhibited mycelial growth less severely than the latters. The results indicate that the fungicides having different modes of action can show different in vitro antifungal activities according to in vitro assays, even if they have similar in vivo disease controlling activities. On the other hand, two rapid and efficient in vitro assays named Microtiter plate methods I (MPM I) and II (MPM II) were developed for the evaluation of fungicides for inhibitory activities against spore germination and mycelial growth of B. cinerea, respectively. The antifungal activities of five fungicides of two chemical groups in MPM I and II were correlated with the inhibitory activities against spore germination and mycelial growth using solid media, respectively.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.339-345
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• 2002

Antifungal substances were isolated from solid cultures of Fusarium equiseti FO-68 obtained from arrowhead and Fusarium sp. FO-510 obtained from egg plant, and then their antifungal activities were investigated against plant pathogenic fungi in vitro and in vivo. An antifungal substance was purifed from rice solid cultures of F. equiseti FO-68 and identified as equisetin. In addition, two antibiotic substances were isolated from solid cultures of Fusarium sp. FO-510 and their chemical structures were determined to be zearalenone and 8'-hydroxyzearalenone. in vitro, equisetin and zearalenone inhibited mycelial growth of most of the plant pathogenic fungi tested, whereas 8'-hydroxyzearalenone hardly inhibited fungal growth. In vitro, equisetin effectively controlled the development of tomato gray mold and tomato late blight. Zearalenone exhibited in vivo antifungal activity against rice blast, rice sheath blight, tomato gray mold, and tomato late blight. However, 8'-hydroxyzearale-none did not control the development of plant diseases except tomato gray mold. This is the first report on the antifungal activities of equisetin, zearalenone, and 8'-hydroxyzearalenone.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.873-877
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• 2007

In order to find microorganisms showing antifungal activities against Plasmodiophora brassicae, which causes club root, Korean salt-fermented fishery products were tested. Several fermented broths of microorgansims isolated from Ammodytes personatus fishery products showed high antifungal activities. The identification of microorganisms and their in vivo antifungal activities are reported herein.

• YAKHAK HOEJI
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• v.39 no.4
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• pp.417-426
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• 1995

6-[(N-4-Chlorophenyl)amino]-7-chloro-5,8-quinolinedione (RCK20) was tested for antifungal activities, in vivo, against Candida albicans. RCK20 was compared vath ketoconazole and fluconazole in the treatment of systemic infection with Candida albicans in normal rats. The therapeutic potential of RCK20 had been assessed by evaluating their activities (survival rate) against systemic infections with in normal mice with Candida albicans. RCK20 improved survival rates as well as ketokonazole. RCK20 had ED$_{50}$. 0.25$\pm$0.18 mg/kg but ketoeonazole and fluconazole had ED$_{50}$, 8.00$\pm$0.73, 10$\pm$0.43 mg/kg respectively. Activities of RCK20 showed superior to that of ketoconazole and fluconazole. Intraperitoneauy administered RCK20 at the ED$_{50}$, 0.25 mg/kg for 7days and 14days reduced Candida albicans colony count in the kidneys and livers as well as ketoconazole and fluconazole at these ED$_{50}$, 8.00 and 10 mg/kg. Acute oral toxicity studies of RCK20 were carried out in ICR mice of both sexes. These acute oral toxicities of RCK20 were low and LD$_{50}$ values were over 2.850 mg/kg in ICR mice. The Genotoxicities of RCK20 had been evaluated. RCK20 was negative in Ames test with Salmonella typhimurium (TA98 and TA100). The clastogenicity was tested on the RCK20 with in vivo mouse micronucleus assay. RCK20 did not show any clastogenic effect in mouse peripheral blood and was negative in mouse micronucleus assay. These results indicate that RCK20 has no genotoxic potential under these experimental condition.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.237-248
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• 2006

Forty one compounds such as ester, sulfonyl ester, carbamate, ether and phosphoyl ester derivatives of thymol(I) and carvacrol(II) were synthesized. These derivatives were identified by IR, GC/MS and $^1H$-NMR spectra. Their antifungal activities were tested against various plant pathogenicfugi. Among them, several compounds were showed potent in vivo antifungal activities. The selected compounds showing in vitro antifungal activities were tested in vivo antifungal activities aganint 5 plant diseases such as rice blast, rice sheath blight, tomato late blight, cucumber anthracnose, and cucumber gray mold. As a result, 2-isopropyl-5-methylphenylacetate(I-1a) effectively suppressed the development cucumber gray mold and rice blast. Methyl(2-isopropyl-5-methylphenoxy)acetate(I-6d) and ethyl 4-(5-methyl-2-isopopylphenoxy)crotonate(I-7d) also showed potent in vivo antifungal actively againt rice sheath blight and tomato late blight, respectively.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.178-186
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• 2007

42 compounds such as ester, sulfonyl ester, phosphoyl ester and ether derivatives of 4-isopropylphenol (I) and 2-isopropylphenol (II) were synthesized. These derivatives were identified by IR, GC/MS and $^{1}H-NMR$ spectra. Their in vitro antifungal activities were tested against 10 plant pathogenic fungi. Among them, several compounds showed potent in vitro antifungal activity. The selected compounds showing potent in vitro antifungal activity were tested for their in vivo antifungal acitvities against 5 plant diseases such as rice blast, rice sheath blast, cucumber anthracnose, cucumber gray mold and tomato late blight. As a result, 2-isopropylphenyl piperonyloate (II-7a) showed a potent in vivo antifungal activity against cucumber anthracnose and tomato late blight, 4-isopropylphenyl 4-methoxybenzenesulfonate (I-6b) effectively inhibited the development of rice blast.

• Mycobiology
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• v.46 no.1
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• pp.52-63
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• 2018

In our previous studies, Bacillus megaterium KU143, Microbacterium testaceum KU313, and Pseudomonas protegens AS15 have been shown to be antagonistic to Aspergillus flavus in stored rice grains. In this study, the biocontrol activities of these strains were evaluated against Aspergillus candidus, Aspergillus fumigatus, Penicillium fellutanum, and Penicillium islandicum, which are predominant in stored rice grains. In vitro and in vivo antifungal activities of the bacterial strains were evaluated against the fungi on media and rice grains, respectively. The antifungal activities of the volatiles produced by the strains against fungal development and population were also tested using I-plates. In in vitro tests, the strains produced secondary metabolites capable of reducing conidial germination, germ-tube elongation, and mycelial growth of all the tested fungi. In in vivo tests, the strains significantly inhibited the fungal growth in rice grains. Additionally, in I-plate tests, strains KU143 and AS15 produced volatiles that significantly inhibited not only mycelial growth, sporulation, and conidial germination of the fungi on media but also fungal populations on rice grains. GC-MS analysis of the volatiles by strains KU143 and AS15 identified 12 and 17 compounds, respectively. Among these, the antifungal compound, 5-methyl-2-phenyl-1H-indole, was produced by strain KU143 and the antimicrobial compounds, 2-butyl 1-octanal, dimethyl disulfide, 2-isopropyl-5-methyl-1-heptanol, and 4-trifluoroacetoxyhexadecane, were produced by strain AS15. These results suggest that the tested strains producing extracellular metabolites and/or volatiles may have a broad spectrum of antifungal activities against the grain fungi. In particular, B. megaterium KU143 and P. protegens AS15 may be potential biocontrol agents against Aspergillus and Penicillium spp. during rice grain storage.

• 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.