• Archives of Pharmacal Research
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• v.29 no.7
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• pp.570-576
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• 2006

Phytoestrogen biochanin A is an isoflavone derivative isolated from red clover Trifolium pratense with anticarcinogenic properties. This study examined the action of biochanin A with the carcinogen activation pathway that is mediated by the aryl hydrocarbon receptor (AhR) in MCF-7 breast carcinoma cells. Treating the cells with biochanin A alone caused the accumulation of CYP1A1 mRNA and an increase in CYP1A1-specific 7-ethoxyresorufin O-deethylase (EROD) activity in a dose dependent manner. A concomitant treatment with 7,12-dimethylbenz[a]anthracene (DMBA) and biochanin A markedly reduced the DMBA-inducible EROD activity and CYP1A1 mRNA level. In addition, the biochanin A treatment alone activated the DNA-binding capacity of the AhR for the dioxin-response element (DRE) of CYP1A1, as measured by the electrophoretic-mobility shift assay (EMSA). EMSA revealed that biochanin A reduced the level of the DMBA-inducible AhR-DRE binding complex. Furthermore, biochanin A competed with the prototypical AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), for binding to the AhR in an isolated rat cytosol. The biochanin A competitively inhibited the metabolic activation of DMBA, as measured by the formation of the DMBA-DNA adducts. These results suggest that biochanin A may thus be a natural ligand to bind on AhR. Therefore, biochanin A may be due to act an antagonist/agonist of the AhR pathway.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1305-1306
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• 2006

A monolayer assembly of anthracene-viologen linked thiol ($AMVC_{8}SH$) was fabricated on a gold electrode by self-assembly method. Structural property of the self-assembled monolayers (SAMs) was carried out by optical and electrochemical method. Firstly, we investigated PL spectrum and UV/visible absorption for the optical properties in solution state. Secondly, we determined the characteristics of charge transfer in different electrolyte solutions by electrochemical quartz crystal microbalance (EQCM). From the data, the PL spectrum and UV/visible absorption were observed and the well-defined shape peaks were nearly equal charges during redox reactions and existed to an excellent linear relationship between the scan rates and existed to currents. The mass change was determined during redox reaction. The mass change behavior of SAMs was not only governed by the mobility of the ion in the viologen but the valence of the ion in the electrolyte solution.

• Archives of Pharmacal Research
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• v.26 no.8
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• pp.585-590
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• 2003

Activity-guided fractionation of the EtOAc-soluble extract of the whole plants of Sida acuta using a bioassay based on the induction of quinone reductase (OR) in cultured Hepa 1c1c7 mouse hepatoma cells, led to the isolation of ten active compounds of previously known structure, quindolinone (1), cryptolepinone (2), 11-methoxyquindoline (3), N-trans-feruloyltyramine (4), vomifoliol (5), loliolide (6), 4-ketopinoresinol (7), scopoletin (8), evofolin-A (9), and evofolin-B (10), along with five inactive compounds of known structure, ferulic acid, sinapic acid, syringic acid, ($\pm$)-syringaresinol, and vanillic acid. These isolates were identified by physical and spectral data measurement. A new derivative of quindolinone, 5,10-dimethylquindolin-11-one (1a) was synthesized and characterized spectroscopically. Of the active substances, compounds 1-3 and 1a exhibited the most potent QR activity, with observed CD (concentration required to double induction) values ranging from 0.01 to 0.12 $\mu$ g/mL. Six compounds were then evaluated in a mouse mammary organ culture assay, with cryptolepinone (2), N-trans-feruloyltyramine (4), and 5,10-dimethylquindolin-11-one (1a) found to exhibit 83.3, 75.0, and 66.7% inhibition of 7,12-dimethylbenz[a]anthracene-induced preneoplastic lesions, respectively, at a dose of 10 $\mu\textrm{g}$/mL.