• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.51-56
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• 2002

An antitumor substance was purified from the culture filtrate of phytopathogenic fungus Alternaria brassicicola SW-3 isolated from soil of a chinese cabbage patch, and its characteristics were investigated. Antitumor activity of A. brassicicola SW-3 was measured by MTT assay. The cytotoxic activity against human cancer cell line was detected in the culture filtrate of A. brassicicola SW-3, but no activity found in mycelium. Antitumor substance was isolated from the culture broth by ethyl acetate extraction and purified by silica gel column chromatography. Structure of the purified compound was analyzed by the instrumental analysis such as $^1$H-NMR, $^{13}$ C-NMR and IR spectroscopy. The purified fungal metabolite of an A. brassicicola SW-3, consists of 11 carbon chain with two hydroxyl groups and two epoxides which is identical to depudecin. The $IC_{50}$/ values of the active compound identified as depudecin were $69\mu$g/mL and $57\mu$g/mL against mouse melanoma B16BL6 cell line, and human hepatoma SK-HEP1 cell line, respectively.

• Journal of Microbiology
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• v.40 no.4
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• pp.289-294
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• 2002

The fungal strain SW-3 having antimicrobial activity was isolated from soil of crucified plants in Pocheon, Kyungki-Do, Korea. Strain SW-3 was identified as Alternaria brassicicola by its morphological characteristics, and confirmed by the analysis of the 18S gene and ITS regions of rDNA. The fungus showed a similarity of 99% with Alternaria brassicicola in the 18S rDNA sequence analysis. A. brassicicola has been reported to produce an antitumor compound, called depudecin. We found that strain SW-3 produced antimicrobial metabolites, in addition to depudecin, during sporulation under different growth conditions. The metabolite of the isolated fungus was found to have strong antifungal activity against Microsporium canis and Trichophyton rubrum, and antibacterial activity against Staphylococcus aureus and Pseudomonas aerogenes. The amount and kind of metabolites produced by the isolate were affected by growth conditions such as nutrients and growth periods.