We purified phytoestrogens from Pueraria root (Pueraria mirifica from Thailand and Pueraria lobata from Korea), which is used as a rejuvenating folk medicine in Thailand and China. Dried, powdered plant material was extracted with 100% ethanol and further separated by concentration, filtration, and thin layer silica gel chromatography. Using the fractions obtained during separation, we first investigated their cytotoxicity in several cancer cell lines from various tissues. The ethanol-extracted components (PE1, PE4) had significant antiproliferative effects on breast cancer cell lines, including MCF-7, ZR-75-1, MDA-MB-231, SK-BR-3, and Hs578T. Second, we compared these results with the cytotoxic effects of known flavonoids, sterols, and coumarins from Pueraria root. The known compounds were not as effective, and occurred in a different polarity region on HPLC. Third, further separation resulted in the isolation of eight different components (Sub PE-A to -H). One of these, PE-D, affected the growth of some breast cancer cell lines (MCF-7, MDA-MB-231) in a dose- and time-dependent manner, as well as the growth of ovarian (2774) and cervical cancer cells (HeLa). Finally, a transfection assay showed that this component had an estrogenic effect similar to 17beta-estradiol, which activates both estrogen receptor a (ER alpha) and ER beta. The NMR analysis determined that spinasterol (stigmasta-7, 22-dien-3beta-ol) is an active cytotoxic component of Pueraria root.
Antineoplastic Agents/isolation & purification/*pharmacology ; Chromatography, High Pressure Liquid ; Estrogen Receptor alpha/agonists ; Estrogen Receptor beta/agonists ; Female ; Humans ; Plant Preparations/therapeutic use ; Plant Roots/*chemistry ; Pueraria/*chemistry ; Research Support, Non-U.S. Gov't ; Stigmasterol/*analogs & derivatives/isolation & purification/pharmacology ; Transfection ; Tumor Cells, Cultured

The localization of estrogen (E2) has been clearly shown in hippocampus, called local hippocampal E2. It enhanced neuronal synaptic plasticity and protected neuron form cerebral ischemia, similar to those effects of exogenous E2. However, the interactive function of hippocampal and exogenous E2 on synaptic plasticity activation and neuroprotection is still elusive. By using hippocampal H19-7 cells, we demonstrated the local hippocampal E2 that totally suppressed by aromatase inhibitor anastrozole. Anastrozole also suppressed estrogen receptor (ER)beta, but not ERalpha, expression. Specific agonist of ERalpha (PPT) and ERbeta (DPN) restored ERbeta expression in anastrozole-treated cells. In combinatorial treatment with anastrozole and phosphoinositide kinase-3 (PI-3K) signaling inhibitor wortmannin, PPT could not improve hippocampal ERbeta expression. On the other hand, DPN induced basal ERbeta translocalization into nucleus of anastrozole-treated cells. Exogenous E2 increased synaptic plasticity markers expression in H19-7 cells. However, exogenous E2 could not enhance synaptic plasticity in anastrozole-treated group. Exogenous E2 also increased cell viability and B-cell lymphoma 2 (Bcl2) expression in H2O2-treated cells. In combined treatment of anastrozole and H2O2, exogenous E2 failed to enhance cell viability and Bcl2 expression in hippocampal H19-7 cells. Our results provided the evidence of the priming role of local hippocampal E2 on exogenous E2-enhanced synaptic plasticity and viability of hippocampal neurons.
Androstadienes/pharmacology ; Animals ; Aromatase Inhibitors/pharmacology ; Cell Line ; Cell Survival/drug effects ; Estrogen Receptor alpha/agonists/metabolism ; Estrogen Receptor beta/agonists/metabolism ; Estrogens/*metabolism/pharmacology ; Hippocampus/cytology/*metabolism ; Hydrogen Peroxide/pharmacology ; Nervous System/*drug effects ; Neuronal Plasticity/*drug effects ; *Neuroprotective Agents ; Nitriles/pharmacology ; Phosphatidylinositol 3-Kinase/antagonists & inhibitors ; Proto-Oncogene Proteins c-bcl-2/biosynthesis ; Rats ; Triazoles/pharmacology

Estrogen Receptor (ERalpha) is a member of superfamily of ligand-activated transcription factors which play critical roles in many biological processes. To screen novel modulators of ERalpha for drug development and biological function research, we developed a mammalian one-hybrid-based high-throughput screening model for ERalpha modulator. We cloned the ERalpha LBD gene from the total mRNA of fat tissue by RT-PCR and fused it with the GAL4 DNA binding domain of pBIND-GAL4 plasmid to construct a chimara expression plasmid pBIND-GAL4-Eralpha(LBD). The L02 cells was cotransfected with pBIND-GAL4-ERalpha(LBD) and a GAL4-responsive luciferase reporter plasmid pGL3-GAL4, and following treatment with test compounds for 24 h, the activities of luciferase were detected to evaluate the transactivities of ERalpha modulators. After manner optimizations of transfection conditions, Estradiol, an agonist control, induced the expression of luciferase in a dose-dependent with EC50 of 0.17 micromol/L, the maximum folds of induction was about 28.1. Tamoxifen, an antagonist control, efficiently suppressed the estradiol-mediated luciferase induction with EC50 of 0.10 micromol/L. Using this screening model, we discovered four ERalpha agonists from 2000 natural and synthetic compounds.
3T3-L1 Cells ; Animals ; Chimera ; metabolism ; DNA-Binding Proteins ; biosynthesis ; genetics ; Estrogen Receptor Modulators ; chemistry ; isolation & purification ; Estrogen Receptor alpha ; agonists ; Genes, Reporter ; genetics ; Genistein ; chemistry ; isolation & purification ; HeLa Cells ; Humans ; Luciferases ; genetics ; metabolism ; Mice ; Models, Chemical ; Saccharomyces cerevisiae Proteins ; biosynthesis ; genetics ; Transcription Factors ; biosynthesis ; genetics ; Transfection