ABSTRACT
Two new and two known compounds were identified as estrogenic constituents from Broussonetia kazinoki. Their structures were elucidated as broussonin A (1), tupichinol C (2), kazinol U (3), and (+)-(2R) kazinol I (4). They showed estrogenic activity with ligand-binding activity of estrogen receptor, transcriptional activity of estrogen-responsive element-luciferase reporter genes. They also control the cellular gene expression levels of estrogen-responsive genes. Phytoestrogens from B. kazinoki may have beneficial effects in the treatment of menopausal symptoms.
Subject(s)
Broussonetia/chemistry , Estrogens/pharmacology , Phytoestrogens/pharmacology , Estrogens/isolation & purification , Female , Humans , Ligands , Molecular Structure , Phenols/isolation & purification , Phenols/pharmacology , Phytoestrogens/isolation & purification , Receptors, Estrogen/drug effects , Receptors, Estrogen/genetics , Receptors, Estrogen/metabolism , Response Elements/drug effects , Transcription, Genetic/drug effectsABSTRACT
The IkappaB kinase (IKK) complex is a central component in the classic activation of the nuclear factor-kappaB (NF-kappaB) pathway. It has been reported to function in physiologic responses, including cell death and inflammation. We have shown that IKK is regulated by oxidative status after transient focal cerebral ischemia (tFCI) in mice. However, the mechanism by which oxidative stress influences IKKs after tFCI is largely unknown. Nuclear accumulation and phosphorylation of IKKalpha (pIKKalpha) were observed 1 h after 30 mins of tFCI in mice. In copper/zinc-superoxide dismutase knockout mice, levels of NF-kappaB-inducing kinase (NIK) (an upstream kinase of IKKalpha), pIKKalpha, and phosphorylation of histone H3 (pH3) on Ser10 were increased after tFCI and were higher than in wild-type mice. Immunohistochemistry showed nuclear accumulation and pIKKalpha in mouse brain endothelial cells after tFCI. Nuclear factor-kappaB-inducing kinase was increased, and it enhanced pH3 by inducing pIKKalpha after oxygen-glucose deprivation (OGD) in mouse brain endothelial cells. Both NIK and pH3 interactions with IKKalpha were confirmed by coimmunoprecipitation. Treatment with IKKalpha small interfering RNA significantly reduced cell death after OGD. These results suggest that augmentation of NIK, IKKalpha, and pH3 in response to oxidative stress is involved in cell death after cerebral ischemia (or stroke).
Subject(s)
Enzyme Induction , I-kappa B Kinase/metabolism , Ischemic Attack, Transient/metabolism , Oxidative Stress , Protein Serine-Threonine Kinases/metabolism , Animals , Cell Death/physiology , Cell Line , Cell Nucleus/metabolism , Endothelial Cells/cytology , Endothelial Cells/metabolism , Endothelial Cells/pathology , Histones/metabolism , Ischemic Attack, Transient/pathology , Male , Matrix Metalloproteinase 9/metabolism , Mice , Mice, Knockout , Phosphorylation , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , Superoxide Dismutase/genetics , Superoxide Dismutase/metabolism , NF-kappaB-Inducing KinaseABSTRACT
Caffeic acid phenethyl ester (CAPE) is an active ingredient of beehive propolis with a structure similar to phenolic acid. The estrogenic effects of propolis were previously demonstrated through the activation of an estrogen receptor. To identify the estrogenic properties of propolis, CAPE was evaluated using in vitro and in vivo methods. CAPE showed selective binding affinity to human estrogen receptor beta (hERbeta) rather than hERalpha. CAPE also reduced ERalpha expression in MCF-7 and MDA 231 cells. In the yeast estrogen receptor transcription assay, CAPE produced the transcriptional activity of estrogen-responsive element with EC(50) values of 3.72 x 10(-6) M. CAPE did not increase the growth of MCF-7 estrogen receptor-positive breast cancer cells in doses ranging from 10(-7) to 10(-5) M. In order to understand how CAPE acts in animals, CAPE was tested by a uterotrophic bioassay. Treatment with CAPE (100, 500 mg/kg) did not increase the uterine weight relative to 3 microg/kg 17beta-estradiol treatment. The results indicate that CAPE, which is a selective agonist to hERbeta, but does not show any estrogenic effect on estrogen receptor-positive breast cancer cells and in immature rat uterine tissue, is a potential selective estrogen receptor modulator.
