Preventive effects of Glycyrrhizae radix extract on estrogen-related endometrial carcinogenesis in mice

Density functional theory study of the structure-antioxidant activity of polyphenolic deoxybenzoins

Quantum chemical calculations based on the density functional theory (DFT) have been employed to study the relationship between the structure and the antioxidant activity of four polyphenolic deoxybenzoins (DOBs) in solvents and the gas phase. The three main working mechanisms, H-atom transfer (HAT), single electron transfer-proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET) have been investigated. The calculated results closely matched experimental values. The results obtained prove that for the HAT mechanism, the most efficient system possessed ortho-dihydroxy functionality. The results suggested that HAT would be the most favourable mechanism for explaining the radical-scavenging activity of polyphenolic DOBs in the gas phase, whereas the SPLET mechanism is the thermodynamically favourable pathway in polar solvents.

Estrogenic effect of three substituted deoxybenzoins

Deoxybenzoins (1-(2,4-dihydroxyphenyl)-2-(4-hydroxyphenyl)ethanone) are possible precursors or metabolites of isoflavanones which may have xenoestrogenic potential on estrogen receptor (ER). In this study we evaluated three 2'-substituted deoxybenzoin derivatives for their estrogenic effect based upon their ability to affect the proliferation of ERα(+) MCF7 cells, ERβ(+) PC3 cells and Hep2 cells stably transfected and expressing either ERα or ERβ. These compounds designated as CMPD3, CMPD6 and CMPD9 had -COOH, -(CH(2))(4)-CH(3) and -CH(3) substitutions, respectively on the 2'-position of the 2,4-dihydroxyphenyl ring of deoxybenzoin. We found that all three compounds increased the proliferation of ERα(+) MCF7 cells (EC(50)~1-12 μM) and ERα(+) Hep2 cells, while causing apoptosis in ERβ(+) PC3 cells (IC(50)~1-5 μM) and ERβ(+) Hep2 cells. The compounds also up-regulated the expression of estrogen sensitive genes, trefoil factor 1 (TFF1, previously known as pS2) and cathepsin-D (CTSD), in these cells. We performed in vitro ER transcription activation assays using Hep2 cells transiently co-transfected with estrogen response element driven luciferase and either ERα or ERβ vectors to ascertain the mechanism of action of these compounds through the 'classical' genomic pathway of estrogenic activity and to determine their ER subtype selectivity. Molecular docking of the compounds with the Ligand Binding Domain of ERα and ERβ showed similar docking scores (Glidescores of -6.5 to -8.5 kcal/mol) indicating that these compounds were ligands of both ERα and ERβ with similar affinity.

Cytoprotective Activity of Glycyrrhizae radix Extract Against Arsenite-induced Cytotoxicity

Licorice, Glycyrrhizae radix, is one of the herbal medicines in East Asia that has been commonly used for treating various diseases, including stomach disorders. This study investigated the effect of licorice on arsenite (As)-induced cytotoxicity in H4IIE cells, a rat hepatocyte-derived cell line. Cell viability was significantly diminished in As-treated H4IIE cells in a time and concentration-dependent manner. Furthermore, results from flow cytometric assay and DNA laddering in H4IIE cells showed that As treatment induced apoptotic cell death by activating caspase-3. Licorice (0.1 and 1.0 mg ml(-1)) treatment significantly inhibited cell death and the activity of caspase-3 in response to As exposure. These results demonstrate that licorice induced a cytoprotective effect against As-induced cell death by inhibition of caspase-3.

The Aqueous Extract of Radix Glycyrrhizae Stimulates Mitogen-Activated Protein Kinases and Nuclear Factor-κB in Jurkat T-Cells and THP-1 Monocytic Cells

Radix Glycyrrhizae (RG) is a medicinal herb extensively utilized in numerous Chinese medical formulae for coordinating the actions of various components in the recipes and strengthening the body functions. In this report, we demonstrate that the aqueous extract of Radix Glycyrrhizae is capable of stimulating the c-Jun N-terminal kinase and p38 subgroups of mitogen-activated protein kinases (MAPKs), and the nuclear factor-κB ( NF κ B ) in Jurkat T-lymphocytes. The activation magnitudes of MAPKs and NF κ B were dose-dependent ( EC 50 ≈ 1 mg/ml ) and time-dependent (maximal around 15–30 minutes). Stimulations of MAPKs and NF κ B were not associated with changes in intracellular Ca 2+ mobilization. Similar activation profiles of MAPK and NF κ B were obtained from THP-1 monocytes treated with the extract. In terms of chemotactic activity, the SDF-induced chemotaxis of Jurkat cells and THP-1 cells were inhibited by RG extract at 1–10 mg/ml, while a lower RG concentration (0.1–0.3 mg/ml) potentiated the SDF-induced chemotaxis for the former, but not the latter cell type. Given the fact that MAPKs and NF κ B are important signaling intermediates for lymphocyte activities, our results suggest that Radix Glycyrrhizae may contain active constituents capable of modulating immuno-responses through various intracellular signaling pathways.

1-(2-Hydr-oxy-3,4-dimethoxy-phen-yl)-2-(4-methoxy-phen-yl)ethanone

In the title compound, C(17)H(18)O(5), the pyrogallol group is almost coplanar with the mean plane of the attached carbonyl group [dihedral angle of 1.95 (13)°] and makes a dihedral angle of 56.01 (10)° with the other benzene ring. Of the three meth-oxy groups, only one is significantly twisted relative to its attached benzene ring [C-O-C-C torsion angles of 4.0 (5), 3.9 (6) and -106.3 (4)°]. Intra-molecular O-H⋯O and C-H⋯O hydrogen bonds help to establish the conformation, and the packing is consolidated by C-H⋯O inter-actions and π-π stacking interactions [centroid-centroid separation = 3.735 (2) Å].

Induction of Apoptosis by Korean Medicine Gagam-whanglyun-haedoktang Through Activation of Caspase-3 in Human Leukemia Cell Line, HL-60 Cells

Gagam-whanglyun-haedoktang (GWH) is a newly designed herbal drug formula based on the traditional oriental pharmacological knowledge for the purpose of treating tumorous diseases. Apoptosis is an evolutionarily conserved suicide program residing in cells. In the present study, apoptosis inducing activities of the decocted water extract of GWH were studied. Results of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that GWH had a strong cytotoxic effect on HL-60 cells. The number of live cells was less than 20% after exposure to 1 mg/ml GWH for 48 h. GWH increased cytotoxicity of HL-60 cells in a dose- and time-dependent manner. The percentage of apoptotic cells by flow cytometric analysis of the DNA-stained cells increased to 28%, 31%, and 37% at 24 h and to 37%, 44%, and 81% at 48 h after treatment with 0.01, 0.1, and 1 mg/ml GWH, respectively. DNA fragmentation also occurred in apoptosis and was characterized by a ladder pattern on agarose gel. In addition, GWH increased the secretion of tumor necrosis factor-alpha. GWH-induced apoptosis was accompanied by activation of caspase-3. These results suggest that GWH induces activation of caspase-3 and eventually leads to apoptosis.

Cytoprotective effects of Glycyrrhizae radix extract and its active component liquiritigenin against cadmium-induced toxicity (effects on bad translocation and cytochrome c-mediated PARP cleavage)

Glycyrrhizae radix has been popularly used as one of the oldest and most frequently employed botanicals in herbal medicine in Asian countries, and currently occupies an important place in food products. Cadmium (Cd) induces both apoptotic and non-apoptotic cell death, in which alterations in cellular sulfhydryls participate. In the present study, we determined the effects of G. radix extract (GRE) and its representative active components on cell death induced by Cd and explored the mechanistic basis of cytoprotective effects of G. radix. Incubation of H4IIE cells with GRE inhibited cell death induced by 10 microM Cd. Also, GRE effectively blocked Cd (1 microM)-induced cell death potentiated by buthionine sulfoximine (BSO) without restoration of cellular GSH. GRE prevented both apoptotic and non-apoptotic cell injury induced by Cd (10 microM) or Cd (0.3-1 microM) + BSO. Inhibition of Cd-induced cell injury by pretreatment of cells with GRE suggested that the cytoprotective effect result from alterations in the levels of the protein(s) responsible for cell viability. GRE inhibited mitochondrial Bad translocation by Cd or CD+BSO, and caused restoration of mitochondrial Bcl(xL) and cytochrome c levels. Cd-induced poly(ADP-ribose)polymerase cleavage in control cells or in cells deprived of sulfhydryls was prevented by GRE treatment. Among the major components present in GRE, liquiritigenin, but not liquiritin, isoliquiritigenin or glycyrrhizin, exerted cytoprotective effect. These results demonstrated that GRE blocked Cd-induced cell death by inhibiting the apoptotic processes involving translocation of Bad into mitochondria, decreases in mitochondrial Bcl(xL) and cytochrome c, and poly(ADP-ribose)polymerase cleavage.

A New Class of Phytoestrogens

Although deoxybenzoins are intermediates in the synthesis of isoflavones, their estrogenic activity has not been investigated. Eleven deoxybenzoins were synthesized and their estrogenicity was evaluated. While their affinities for estrogen receptors (ER) ERalpha and ERbeta were found grossly comparable to those of daidzein, some exhibited considerable selectivity and transcriptional bias toward ERbeta, which appeared to allow for enhancement of ER-mediated transcription via deoxybenzoin binding of ERbeta. Their activity to stimulate the proliferation of ER-positive breast cancer cells and regulate the expression of endogenous and stably transfected reporter genes differed considerably, with some inhibiting cell proliferation while effectively inducing gene expression at the same time. Molecular modeling confirmed that deoxybenzoins fit well in the ligand binding pocket of ERbeta, albeit with different orientations. Our data support the view that deoxybenzoins constitute a promising new class of ERbeta-biased phytoestrogens.

Association of cellular apoptosis with anti-tumor effects of the Chinese herbal complex in endocrine-resistant cancer cell line

We previously reported the special herbal complex (Hoelen, Angelicae radix, Scutellariae radix and Glycyrrhizae radix) suppressed telomerase activity in chemo-endocrine-resistant cancer cell lines. The present study attempted to determine whether the above herbal complex induces apoptosis in endocrine-resistant AN3CA and adriamycin-resistant MCF7/ADR carcinoma cells. Exposure to the herbal complex decreased cell viability in a time- and dose-dependent manner in the 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. The agent induced cellular apoptosis was determined by DNA fragmentation and a nuclear staining assay. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) showed the decreased expression of apoptosis-related genes, bcl-2, c-myc and human telomerase catalytic subunit (hTERT). A decreased protein level of bcl-2 and c-myc was also determined by Western blot analysis. The data imply that the decreased expression of the genes via suppressing telomerase activity is involved in cellular apoptosis in endocrine-resistant AN3CA cells. Thus, it is suggested that the special herbal complex may be a promising candidate for the treatment of endocrine-resistant gynecologic carcinomas.

Shimotsu-to is the agent in Juzen-taiho-to responsible for the prevention of endometrial carcinogenesis in mice

We have found that Juzen-taiho-to has a preventive effect on endometrial carcinogenesis in mice (Carcinogenesis 22 (2001) 587). In the present study, the constituents of Juzen-taiho-to responsible for this effect were explored using a short-term experiment. Thirty female ICR mice were divided into five groups: Group 1 was given a diet containing 0.2% of Juzen-taiho-to and 5ppm estradiol-17beta (E(2)); Group 2 was given a diet containing Shimotsu-to (0.07%) and E(2) (5ppm); Group 3 received Shikunshi-to (0.08%) and E(2) (5ppm) in the diet; Group 4 was given 5ppm E(2) in the diet; and Group 5 served as a control. Exposure of Juzen-taiho-to or Shimotsu-to decreased E(2)-stimulated expression of estrogen-related gene c-fos mRNA (P<0.05), and the cytokines interleukin-1alpha mRNA and tumor necrosis factor alpha mRNA P<0.01). A similar trend was not found upon treatment with Shikunshi-to. These findings suggest that Shimotsu-to is responsible for the inhibitory effects of Juzen-taiho-to on the estrogen-related endometrial carcinogenesis in mice.

Inhibitory effects of toremifene on N-methyl-N-nitrosourea and estradiol-17beta-induced endometrial carcinogenesis in mice

Short- and long-term experiments were designed to determine the effects of toremifene (TOR) on estrogen-related endometrial carcinogenesis in mice. In the short-term experiment, a single low dose of TOR (0.2 mg / 30 g body weight) decreased expression of c-fos, interleukin (IL)-1alpha, estrogen receptor (ER)-alpha mRNAs and corresponding proteins induced by estradiol-17beta (E(2)), in the uteri of the ovariectomized mice. Expression of ER-beta mRNA was increased by the TOR treatment, compared with the control. In the long-term experiment, 106 female ICR mice were given N-methyl-N-nitrosourea (MNU) into their uterine corpora. The animals were divided into four groups as follows: group 1, E(2) diet (5 ppm) plus TOR (0.2 mg / 30 g body weight, subcutaneously, every four weeks); group 2, E(2) diet alone; group 3, basal diet plus TOR. Group 4 served as the control. TOR treatment decreased the incidence of MNU and E(2)-induced endometrial adenocarcinoma and atypical hyperplasia at the termination of the experiment (30 weeks after the start). These results suggest that TOR exerts preventive effects against estrogen-related endometrial carcinogenesis in mice, through the suppression of c-fos as well as IL-1alpha expression induced by E(2). Such suppressive effects of TOR may be related to the decreased ER-alpha and increased ER-beta expressions.

Preventive effects of isoflavones, genistein and daidzein, on estradiol-17beta-related endometrial carcinogenesis in mice

The effects of isoflavones (genistein and daidzein) on endometrial carcinogenesis in mice were investigated in two experiments. In the short-term experiment (2 weeks), single subcutaneous (s.c.) administration of genistein [1 mg / 30 g body weight (b.w.)] significantly decreased the levels of estradiol-17beta (E(2)) (5 ppm in diet)-induced expression of c-jun, interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha) mRNAs in the uteri of ovariectomized mice (P < 0.005, P < 0.05 and P < 0.01, respectively). Daidzein significantly inhibited E(2)-induced expression of c-fos and IL-1alpha (P < 0.01, P < 0.01 respectively). In the long-term experiment (30 weeks), 140 female ICR mice were given N-methyl-N-nitrosourea-containing solution (1 mg / 100 g b.w.) and normal saline (as controls) into their left and right uterine corpora, respectively. They were divided into six groups; group 1 was given E(2) (in diet) alone. Group 2 was given E(2) and genistein (1 mg / 30 g b.w., s.c., every four weeks). Group 3 was exposed to E(2) and daidzein (1 mg / 30 g b.w., s.c., every four weeks). Groups 4 and 5 respectively received genistein and daidzein, and were kept on the basal diet. Group 6 was kept on the basal diet and served as a control. At the termination of the experiment, incidences of endometrial adenocarcinoma and atypical endometrial hyperplasia of the group given E(2) and genistein or daidzein were significantly lower than of the group with E(2) alone (P < 0.01 and P < 0.05, respectively). It is suggested that both genistein and daidzein have an inhibitory effect on estrogen-related endometrial carcinogenesis in mice, possibly by suppressing expression of estrogen-induced estrogen-related genes c-fos and c-jun, and internal cytokines IL-1alpha and TNF-alpha through a cytokine and estrogen receptor-mediated pathway.

Preventive effects of Juzen-taiho-to on N-methyl-N-nitrosourea and estradiol-17beta-induced endometrial carcinogenesis in mice

Two experiments were conducted to determine effects of Juzen-taiho-to on endometrial carcinogenesis in mice. In the first experiment, Juzen-taiho-to treatment (2 weeks) decreased the levels of estradiol-17beta (E(2))-stimulated expression of c-fos/jun mRNA and their oncoproteins, determined by reverse transcription-polymerase chain reaction and Southern blot analysis, and the immunohistochemical method, in the uteri of ovarectomized mice. For the second experiment, 93 female ICR mice were given N-methyl-N-nitrosourea (MNU) solution (1 mg/100 g body weight) and normal saline (as controls) into their left and right uterine corpora, respectively, and were divided into four groups. Group 1 was given a diet containing 0.2% Juzen-taiho-to and 5 p.p.m. E(2). Group 2 was given a diet containing 5 p.p.m. E(2) alone. Group 3 was given a diet containing 0.2% Juzen-taiho-to alone. Group 4 was kept on the basal diet alone and treated as a control. Juzen-taiho-to treatment significantly decreased incidences of the uterine endometrial atypical (P<0.01), complex (P<0.05) and simple hyperplasias (P<0.01), under estrogenic stimulation. It is suggested that Juzen-taiho-to has an inhibitory effect on E2-related endometrial carcinogenesis in mice, relevantly through suppression of estrogen-induced c-fos/jun-expression.

Preventive effects of danazol on endometrial carcinogenesis in mice

Short and long-term experiments were designed to determine effects of danazol on estrogen-related endometrial carcinogenesis in mice. The short-term assays showed that danazol decreased expression levels of c-fos/jun mRNA and their oncoproteins induced by estradiol-17beta (E2). For the long-term assay, 85 female ICR mice were given N-methyl-N-nitrsourea solution into their uterine corpora. The animals were divided into three groups as follows: Group 1, E2-diet (5 ppm) plus danazol (2 mg/body (s.c.), every 4 weeks); Group 2, E2-diet alone, Group 3, basal diet alone. At 30 weeks, incidences of atypical and complex endometrial hyperplasia were significantly decreased by danazol-treatment. These results suggest that danazol has preventive effects on estrogen-related endometrial carcinogenesis in mice, through the suppression of estrogen-induced c-fos/jun-expression.