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Extraction and Bioassay of Allelochemicals in Jerusalem Artichoke
Sungwook Chae,Ho-Jin Lee 韓國作物學會 2001 Korean journal of crop science Vol.46 No.4
Helianthus tuberosus has been known to inhibit the growth of weeds and other plants sharing its habitat. This study was conducted to identify the allelochemicals of Helianthus tuberosus which were extracted with water and solvents. Aqueous extracts of leaf, stem, root, tuber and tuber peel of Helianthus tuberosus except tuber did not show significant differences in phytotoxicity to alfalfa seedlings. It was considered that Helianthus tuberosus contained fewer or less potential water-soluble substances that were toxic to alfalfa. Methanol extract of leaves of Helianthus tuberosus was sequentially partitioned in increasing polarity with n-hexane, ethylacetate and n-butanol. Each extract had a yield of 148, 12, 15.7 and 9.5g, respectively. Inhibitory effects on germination of alfalfa seeds treated with four fractions were not significantly different. But the significant reductions on hypocotyl length were observed for all the solvent extracts. Among the four fractions, the ethylacetate fraction showed the most significant inhibition effect on bioassay with alfalfa. Further separation of the active ethylacetate fraction by open column chromatography led to the 25 subfractions. In bioassay of each sub-fraction with alfalfa seeds, sub-fraction No. 13 showed the most inhibitory effect on seedling growth. 1 H NMR and gas chromatography-mass spectrometry analysis revealed that sub-fraction No. 13 was the mixture of straight-chain saturated fatty acids.
Combined Effect of Radiation and 7β-Hydroxycholesterol on Human Cervical Cancer Cells in vitro
Sungwook Chae,Kyoung Ah Kang,Kyoung Hwa Lee,Rui Zhang,Myung Sun Jung,Jin Won Hyun 한국환경성돌연변이발암원학회 2005 한국환경성돌연변이·발암원학회지 Vol.25 No.3
7β-Hydroxycholesterol (cholest-5-ene-3, 7-diol, 7β-OHC) showed the cytotoxicity on human cervical carcinoma cells (HeLa), 10 μM of 50% inhibitory concentration. We evaluated 7β-OHC as the possibility of radiation sensitizer. The combination effect of 7β-OHC and γ-irradiation was measured using colony forming assay and flow cytometer with propidium iodide and DiOC_6 stained cells, respectively. The combined treatment of 7β-OHC and γ-irradiation did not show significant enhancing effects on HeLa cells.
Chae Sungwook,Kang Kyoung Ah,Lee Kyoung Hwa,Zhang Rui,Jung Myung Sun,Hyun Jin Won Korean Environmental Mutagen Society 2005 한국환경성돌연변이·발암원학회지 Vol.25 No.2
25-Hydroxycholesterol (cholest-5-ene-3, 25-diol, 25-OHC) showed the cytotoxicity on HeLa human cervix and NCI-H460 human lung cancer cells, $0.5{\mu}M\;of\;50\%$ inhibitory concentration. We studied 25-OHC as the possibility of radiation sensitizer. The combination effect of 25-OHC and y-irradiation measured using flow cytometer with propidium iodide stained cells. The combined treatment of 25-OHC and $\gamma-irradiation$ did not show significant enhancing effects on Hela and NCI-H460 cells.
Sungwook Chae,Kyoung Ah Kang,Kyoung Hwa Lee,Rui Zhang,Myung Sun Jung,Jin Won Hyun 한국환경성돌연변이발암원학회 2005 한국환경성돌연변이·발암원학회지 Vol.25 No.2
25-Hydroxycholesterol (cholest-5-ene-3, 25-diol, 25-OHC) showed the cytotoxicity on HeLa human cervix and NCI-H460 human lung cancer cells, 0.5 μM of 50% inhibitory concentration. We studied 25-OHC as the possibility of radiation sensitizer. The combination effect of 25-OHC and γ-irradiation measured using flow cytometer with propidium iodide stained cells. The combined treatment of 25-OHC and γ-irradiation did not show significant enhancing effects on Hela and NCI-H460 cells.
Zhang, Rui,Chae, Sungwook,Lee, Jun Hwa,Hyun, Jin Won Wiley Subscription Services, Inc., A Wiley Company 2012 Journal of cellular biochemistry Vol.113 No.6
<P><B>Abstract</B></P><P>Butin (7,3′,4′‐trihydroxydihydroflavone), a flavonoid with antioxidant activity, was recently reported to protect cells against H<SUB>2</SUB>O<SUB>2</SUB>‐induced apoptosis, oxidative DNA damage and oxidative mitochondrial dysfunction. The objective of the present study was to elucidate the mechanism by which butin protects mitochondria. The antioxidant function of manganese superoxide dismutase (Mn SOD) is important in preventing oxidative stress. While exposure to H<SUB>2</SUB>O<SUB>2</SUB> reduced the expression of Mn SOD in Chinese hamster lung fibroblast (V79‐4), the addition of butin restored Mn SOD expression at both the mRNA and protein levels, resulting in increased Mn SOD activity. The transcription factor NF‐E2‐related factor 2 (Nrf2) regulates Mn SOD gene expression by binding to the antioxidant responsive element (ARE). Butin enhanced the nuclear translocation and ARE‐binding activity of Nrf2, which was decreased by H<SUB>2</SUB>O<SUB>2</SUB>. The siRNA‐mediated knockdown of Nrf2 attenuated butin‐induced Mn SOD expression and activity. Further, phosphatidylinositol 3‐kinase (PI3K)/protein kinase B (PKB, Akt) contributed to the ARE‐driven Mn SOD expression. Butin activated PI3K/Akt and exposure to either LY294002 (a PI3K inhibitor), Akt inhibitor IV (an Akt‐specific inhibitor), or Akt siRNA suppressed the butin‐induced activation of Nrf2, resulting in decreased Mn SOD expression and activity. Finally, the cytoprotective effect of butin against H<SUB>2</SUB>O<SUB>2</SUB>‐induced cell damage was suppressed by the siRNA‐mediated knockdown of Mn SOD. These studies demonstrate that butin attenuates oxidative stress by activating Nrf2‐mediated Mn SOD induction via the PI3K/Akt signaling pathway. J. Cell. Biochem. 113: 1987–1997, 2012. © 2012 Wiley Periodicals, Inc.</P>
현진원,강경아,유호진,Sungwook Chae,Kyoung Hwa Lee,Rui Zhang,Myung Sun Jung,김진숙 한국생물공학회 2005 Biotechnology and Bioprocess Engineering Vol.10 No.6
Homogentisic acid was found to scavenge intracellular reactive oxygen species (ROS), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and thus prevented lipid peroxidation in human fibroblast (WI 38) cells. The radical scavenging activity of homogentisic acid was found to protect WI 38 cells against hydrogen peroxide (H2O2) induced oxidative stress, via the activation of extracellular signal regulated kinase (ERK) protein. Homogentisic acid increased the activity of catalase. Hence, from the present study, it is suggested that homogentisic acid protects WI 38 cells against H2O2 damage by enhancing the intracellular antioxidative activity.
Cytotoxic Effect of 7β-Hydroxycholesterol on Human NCI-H460 Lung Cancer Cells
Kang, Kyoung Ah,Chae, Sungwook,Lee, Kyoung Hwa,Park, Moon Taek,Lee, Su Jae,Lee, Yun Sil,Hyun, Jin Won Pharmaceutical Society of Japan 2005 Biological & pharmaceutical bulletin Vol.28 No.8
<P>The cytotoxic activity of 7β-hydroxycholesterol (7β-OHC) was evaluated on human NCI-H460 lung cancer cells. 7β-OHC decreased clonogenic survival of NCI-H460 in a dose dependent pattern. 7β-OHC induced apoptosis in NCI-H460, with the characteristic features like increase in sub-G<SUB>1</SUB> hypodiploid (apoptotic) cells, and apoptotic body formation, as evidenced by flow cytometry and fluorescence microscope, respectively. Apoptosis was also associated with loss of mitochondrial transmembrane potential, and the activation of caspases 9 and 3. 7β-OHC resulted in generation of reactive oxygen species (ROS) during apoptosis. On the whole, the results indicated that 7β-OHC inhibited the proliferation of NCI-H460 cells through apoptosis <I>via</I> caspase activation.</P>