• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1654-1660
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• 1999

The free phenolic acid fraction of the chloroform extract from 75% ethanol extract of Rhus verniciflua STOKES (RCF) showed stronger antioxidative activity than BHT, BHA and ${\delta}-tocopherol$ at the same concentration. RCF components were isolated and identified by silica gel column chromatography, thin layer chromatography, mass spectrometer and $^1H-NMR\;and\;^{13}C-NMR$. The antioxidative activity was confirmed by electron donating activity, Rancimat method and thiobarbituric acid test in liposome system. RCF-11 could be further separated into three fractions. The antioxidative active compounds were purified and identified as gallic acid, butin and butein. The RCF-13 was purified and identified as sulfuretin.

• Mycobiology
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• v.29 no.3
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• pp.164-169
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• 2001

A new medium for studies of diversity among populations of $A_1\;and\;A_2$ mating types of Phytophthora infestans has been evolved. The rye A agar and V-8 juice agar media on which P. infestans grows well have been amended with rhizome powder of Cyperus rotundus. A total of 259 isolates of $A_1\;and\;A_2$ mating types representing Japan, Korea, India, Taiwan, Indonesia, Thailand, China, Nepal, U.K and Medico were screened for their growth response on these two media. Most of the A1 isolates did not grow well on them except Thailand while growth of $A_2$ mating types differed as some grew on it whereas others did not. It is quite likely that the populations of $A_2$ mating types that did not grow well on rhizome-amended medium are of different clonal lineage. This suggests that this medium can be used for the study of diversification among the isolates of the same or both the mating types as well as to detect the newly introduced genetically different isolates of P. infestans in a locality where it was not reported earlier.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1384-1391
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• 2006

The signal transduction system is one of the most important devices involved in maintaining life, and many protein kinases are included in the cellular signal transduction system. Finding a protein kinase inhibitor is very valuable, as it can be used to study cell biology and applied to pharmaceuticals. For the efficient and rapid screening of protein kinase inhibitors, two assay systems were combined; the nonradioactive protein kinase assay system that uses an FITC-labeled IRS-2 peptide and the cell-based paper disc assay system that uses Streptomyces griseus as the indicator strain. Among 330 kinds of herb extracts tested, the extract of Dalbergia odorifera exhibited the strongest inhibitory activity in the two assay systems and was selected for further isolation. Based on solvent extraction and many steps of chromatography, seven compounds were finally separated to homogeneity and their structures determined by $^{1}H$ and $^{13}C$ NMR spectroscopies. Four were to be flavonoids and identified as butin ($C_{15}H_{12}O_5$, Mw=272.07), 3'-hydroxymelanetin ($C_{16}H_{12}O_6$, Mw=300.06), liquiritigenin ($C_{15}H_{12}O_4$, Mw=256.07), and 2'-hydroxyformononetin ($C_{16}H_{12}O_{5}$, Mw=284.07). 3'-Hydroxymelanetin inhibited the phosphorylation of the GSK3 protein by Akt to 37% at a concentration of $10{\mu}g/ml$ and showed the strongest cytotoxicity ($ED_{50}<50{\mu}g/ml$) against the human cancer cell line HCT116. Under the same conditions, liquiritigenin also inhibited the phosphorylation of GSK3 by Akt to 26%, and its cytotoxicity against the HCT116 cell line was lower than $100{\mu}g/ml$.