Pure Genistein Research Articles

Genistein encapsulated inulin-stearic acid bioconjugate nanoparticles: Formulation development, characterization and anticancer activity

Achieving controlled and site-specific delivery of hydrophobic drugs in the colon environment is a major challenge. The primary goal of this research was to synthesize inulin-stearic acid (INU-SA) conjugate and to evaluate its potential in the site-specific delivery of genistein (GEN) for the treatment of colon cancer. INU is a hydrophilic polysaccharide biological macromolecule was modified with hydrophobic SA to form amphiphilic conjugate (INU-SA) which can self-assemble into spherical nanoparticles with interesting drug release properties. The hydrophobic GEN was encapsulated into the INU-SA conjugate to prepare GEN loaded nanoparticles (GNP). The prepared GNP possessed nano size (115 nm), good colloidal dispersibility (0.066 PDI), and high drug encapsulation efficiency (92.2%). The release behaviour of GNP indicated the site-specific release of GEN, only 3.4% at gastric pH while 94% at intestinal pH. The prepared GNP showed potential cytotoxicity against HCT 116 human colorectal cancer cells, as demonstrated by antiproliferation and apoptosis assays. The observed half maximum inhibitory concentration (IC50) value of GNP (5.5 μg/mL) was significantly lower than pure GEN (28.2 μg/mL) due to higher cellular internalization of GNP than free GEN. Therefore, this research suggests a way to improve the therapeutic effectiveness of natural biomolecules using modified and biocompatible polysaccharide INU.

Formulation of Genistein-HP β Cyclodextrin-Poloxamer 188 Ternary Inclusion Complex: Solubility to Cytotoxicity Assessment.

The current study was designed to prepare the inclusion complex Genistein (GS) using Hydroxypropyl β cyclodextrin (HP β CD) and poloxamer 188 (PL 188). The binary inclusion complex (GS BC) and ternary inclusion complex (GS TC) were developed by microwave irradiation technique and evaluated for a comparative dissolution study. Further, the samples were assessed for FTIR, DSC, XRD, and NMR for the confirmation of complex formation. Finally, antioxidant and antimicrobial studies and cytotoxicity studies on a breast cancer (MCF-7) cell line were conducted. The dissolution study result showed a marked increment in GS dissolution/release after incorporation in binary (GS: HP β CD, 1:1) and ternary (GS: HP β CD: PL 188; 1:1:0.5) inclusion complexes. Moreover, the ternary complex exhibited a significant enhancement (p < 0.05) in dissolution than did the binary complexes. This might be due to the presence of PL 188, which helps in solubility enhancement of GS. DSC, XRD and SEM evaluation confirmed the modification in the structure of GS. FTIR and NMR results indicated the formation of an inclusion complex. The antioxidant and antimicrobial activity results revealed that GS TC has shown significant (p < 0.05) higher activity than pure GS. The cytotoxicity study results also depicted concentration-dependent cytotoxicity. GS TC exhibited significantly (p < 0.05) high cytotoxicity to cancer cells (IC50 = 225 µg/mL) than pure GS (IC50 = 480 µg/mL). Finally, it was concluded that a remarkable enhancement in the dissolution was observed after the inclusion of GS in the ternary complex and it therefore has significant potential for the treatment of breast cancer.

Formulation of ternary genistein β-cyclodextrin inclusion complex: In vitro characterization and cytotoxicity assessment using breast cancer cell line

Genistein (GT) is a poorly water-soluble flavonoid and reported for different biological activity. The present work was designed to prepare the inclusion complex using β-Cyclodextrins (β-CDs) as complexing agent and D -α-Tocopherol polyethylene glycol 1000 succinate (TPGS) as ternary substance to enhance the solubility and in vitro activity. The inclusion complex was prepared by solvent evaporation method and characterized for different physicochemical parameters. The selected GT ternary inclusion complex was further evaluated for in vitro antioxidant and cell viability study against breast cancer cell line. The phase solubility study result data revealed significantly marked enhancement in the solubility of GT. The complexation efficiency (CE) and stability constant (Ks) of GTBIC and GTTIC2 was found to 0.31% and 0.48% as well as 419.67 M-1 and 654.98 M-1, respectively. The saturation solubility results depicted a significant (p < 0.05) enhancement in the saturation solubility (2.61 and 5.27-fold) of GT. Genistein ternary inclusion complex (GTTIC2) prepared with TPGS (0.05%, w/w) showed the maximum release pattern 96.5 ± 3.98% in 90 min. The DSC and XRD spectra showed the transformation of crystalline GT into the amorphous state after complexation. The infrared (IR) and nuclear magnetic resonance (NMR) spectra confirms the formation of inclusion complex by showing changes in the characteristic peaks. GTTIC2 formulation exhibited significantly greater in-vitro antioxidant and cell viability activity against MCF7 cell than pure GT. The improved activity can be attributed to the enhanced solubility of Genistein by effective complexation in β-CDs and TPGS.

Alterations in the Intestinal Morphology, Gut Microbiota, and Trace Mineral Status Following Intraamniotic Administration (Gallus gallus) of Genistein

Abstract Objectives Assess the effects of intraamniotic genistein administration on brush border membrane (BBM) functionality, intestinal morphology, cecal microbiome and Fe status in-vivo (Gallus gallus). Methods Broiler chickens (Gallus gallus, n = 39) were injected in ovo (day 17 of embryonic incubation) with varying concentrations of 1 mL pure genistein in 18 Ω H2O. Two treatment groups (1.25, 2.5%), two controls (water and non-injected), and a positive control (5% inulin) were administered. Upon hatch, blood was taken for hemoglobin determination and chicks were then euthanized. Nutritional status was assessed using pectoral muscle glycogen storage and body weight analysis. Duodenal and cecal tissues were excised for BBM morphometric analysis, mRNA gene expression of relevant BBM Fe transporter proteins, and 16S rRNA gene sequencing was done to evaluate gut microbiota modulation in the intestinal cecum. Results Preliminary results reveal significant increase in body weight, decrease of cecum weight, and increase in villus surface area with the higher dose of genistein administration (P &amp;lt; 0.05) compared to controls. Blood hemoglobin was found to be increased in the genistein-treated groups when compared to the controls (P &amp;lt; 0.05). Additionally, genistein administration downregulated the expression of duodenal cytochrome B (DcytB) and divalent metal transporter 1 (DMT1) and upregulated the expression of ferroportin with a dose responsive effect, indicating improved Fe physiological status. Further, administration of genistein altered the composition and function of cecal microbiota. Conclusions Genistein is a compound present in multiple staple food crops, including soybeans and chickpeas, and may be extracted and potentially used to enhance dietary Fe bioavailability and improve Fe deficiency in vulnerable populations. Recent evidence suggests a physiological role for genistein administration in improving the functionality and development of the BBM, improving Fe status, affecting the intestinal microbiome, as well as improving physiological status. Funding Sources N/A.

Synthesizing efficacious genistein in conjugation with superparamagnetic Fe3O4 decorated with bio-compatible carboxymethylated chitosan against acute leukemia lymphoma

BackgroundGenistein (C15H10O5) is a soy isoflavone with anti-cancer properties such as inhibition of cell growth, proliferation and tumor invasion, but effective dosage against hematopoietic malignant cells was not in non-toxic range. This property cause to impede its usage as chemotherapeutic agent. Therefore, this hypothesis raised that synthesizing biocompatible nanoparticle could assist to prevail this struggle.MethodsGenistein covalently attached on Fe3O4 nanoparticles decorated with carboxymethylated chitosan to fabricate Fe3O4-CMC-genistein in alkaline circumstance. This obtained nanoparticles were evaluated by TEM, DLS, FTIR, XRD and VSM and its anti-cancer effect by growth rate and MTT assays as well as flow cytometer on ALL cancer cell lines.ResultsDifferent evaluations indicated that the drug delivery vehicle had a mean diameter size around 12ƞm with well bounded components. This system presented high degree of magnetization and superparamagnetic properties as well as good water solubility. In comparison with pure genistein, significant growth inhibition on hematopoietic cancer cells in lower dose of genistein nano-conjugated onto Fe3O4-CMC. It increased long lasting effect of genistein in cancer cells also.ConclusionThis delivery system for genistein could be remarkably promised and futuristic as biocompatible chemotherapeutic agent against hematopoietic malignant cells.

Evaluation of Solubility Characteristics of a Hybrid Complex of Components of Soy.

The purpose of this study was to evaluate the solubilities and physicochemical properties of solid dispersions of daidzein (DDZ) and genistein (GST) (the major isoflavones in soybeans) in γ-cyclodextrin (γCD). Dispersions were prepared in distilled water using a three-dimensional ball mill (3DGMw). Phase solubility diagrams confirmed that DDZ/γCD and GST/γCD formed AL type inclusion complexes with a molar ratio of 1:1. A new peak due to inclusion complexes was observed in the results of powder X-ray diffraction (3DGMw(DDZ/γCD = 1:1) and 3DGMw(GST/γCD = 1:1)). Dissolution tests using distilled water found that solubilities of 3DGMw(DDZ/γCD = 1:1) and 3DGMw(GST/γCD = 1:1) were approximately 37- and 51-fold higher, respectively, than the solubilities of pure DDZ and GST. These observations are expected to expand the usefulness of cogrinding of DDZ or GST with γCD using a three-dimensional ball mill.

Intranasal Delivery of Genistein-Loaded Nanoparticles as a Potential Preventive System against Neurodegenerative Disorders.

Genistein has been reported to have antioxidant and neuroprotective activity. Despite encouraging in vitro and in vivo results, several disadvantages such as poor water solubility, rapid metabolism, and low oral bioavailability limit the clinical application of genistein. The aim of this study was to design and characterize genistein-loaded chitosan nanoparticles for intranasal drug delivery, prepared by the ionic gelation technique by using sodium hexametaphosphate. Nanoparticles were characterized in vitro and their cytotoxicity was tested on PC12 cells. Genistein-loaded nanoparticles were prepared, and sodium hexametaphosphate was used as a valid alternative to well-known cross-linkers. Nanoparticle characteristics as well as their physical stability were affected by formulation composition and manufacturing. Small (mean diameters of 200–300 nm) and homogeneous nanoparticles were obtained and were able to improve genistein penetration through the nasal mucosa as compared to pure genistein. Nanoparticle dispersions showed a pH consistent with the nasal fluid and preserved PC12 cell vitality.

Genistein Supplementation and Cardiac Function in Postmenopausal Women with Metabolic Syndrome: Results from a Pilot Strain-Echo Study.

Genistein, a soy-derived isoflavone, may improve cardiovascular risk profile in postmenopausal women with metabolic syndrome (MetS), but few literature data on its cardiac effects in humans are available. The aim of this sub-study of a randomized double-blind case-control study was to analyze the effect on cardiac function of one-year genistein dietary supplementation in 22 post-menopausal patients with MetS. Participants received 54 mg/day of genistein (n = 11) or placebo (n = 11) in combination with a Mediterranean-style diet and regular exercise. Left ventricular (LV) systolic function was assessed as the primary endpoint, according to conventional and strain-echocardiography measurements. Also, left atrial (LA) morphofunctional indices were investigated at baseline and at the final visit. Results were expressed as median with interquartile range (IQ). A significant improvement of LV ejection fraction (20.3 (IQ 12.5) vs. −1.67 (IQ 24.8); p = 0.040)), and LA area fractional change (11.1 (IQ 22.6) vs. 2.8 (9.5); p = 0.034)) were observed in genistein patients compared to the controls, following 12 months of treatment. In addition, body surface area indexed LA systolic volume and peak LA longitudinal strain significantly changed from basal to the end of the study in genistein-treated patients. One-year supplementation with 54 mg/day of pure genistein improved both LV ejection fraction and LA remodeling and function in postmenopausal women with MetS.

Preparation of a 1:1 cocrystal of genistein with 4,4′-bipyridine

Based on analysing the relationship between the possible number of intermolecular O–H···N hydrogen bonds and the stoichiometric ratio, a 1:1 C15H10O5·C10H8N2 (genistein–4,4′-bipyridine) cocrystal has been prepared by solution evaporation and characterized. This work successfully demonstrates that the stoichiometric ratio could be inferred by analysing the possible number of intermolecular hydrogen bonds between flavonoids and amines. The strategy provides a facile route for rational designing cocrystal of flavonoids with amines. Additionally, the title cocrystal shows advantages in terms of solubility and antibacterial properties in comparison to pure genistein.

Soy and the soy isoflavone genistein promote adipose tissue development in male mice on a low-fat diet.

Several nutrients act as phytoestrogens, being anti-adipogenic when consumed with a fat-rich diet. Their effect on a low-fat diet (LFD) background is unknown. We tested soy and genistein effects on adipose tissue in LFD-fed mice and genistein activity in the 3T3-L1 adipogenesis model. C57BL/6 J male mice were fed an 8.5% soy-supplemented LFD (SS-LFD) or a soy-free LFD (SF-LFD) for 147 days. Groups of 3-week-old (pubertal) and 6-week-old (adult) mice on the SF-LFD were also treated with 17ß-estradiol (E2, 5 µg/kg/day) ip or pure genistein (5 mg/kg/day) by gavage for 15 days. Body fat deposition and gene expression profiles were evaluated. E2 and genistein effects on ERα, ERβ and PPARγ transcriptional activities were characterized in ERα- or ERβ-transfected 3T3L1 cells during differentiation, by the use of reporter plasmids. The SS-LFD group increased fat mass compared with the SF-LFD group. Genistein alone increased while E2 decreased fat pads in the 15-day-treated mice. In visceral fat, genistein differentially regulated 13 metabolic pathways compared to E2. PPARγ-controlled genes were downregulated by E2, while they were upregulated by genistein. In 3T3-L1 cells, genistein activated ERβ-driven transcription, differentiation and lipid accumulation, while inhibited ERα-driven transcription, without effects on lipid accumulation. E2 activated both ERs only in preadipocytes. In differentiated untransfected cells, genistein inhibited PPARγ, while activated PPARγ in the presence of ERβ. Soy and genistein at nutritional doses induce fat development in LFD-fed mice and adipogenesis in 3T3-L1 cells, with a mechanism that involves, at least in vitro, ERβ and is dependent on cell differentiation stage.

Lose dose genistein inhibits glucocorticoid receptor and ischemic brain injury in female rats

Although acute bolus of genistein treatment has been shown to protect against neuronal damage in experimental brain injury animal models, chronic continuous low dose treatment of genistein on ischemic brain injury has not been well elucidated. In the present study, female rats were received either pure genistein (0.1mg/kg/day via osmotic minipumps) or placebo at the time of ovariectomy, and transient forebrain ischemia was induced 7days later. Results demonstrated that genistein treatment for 14days significantly improved ischemic neuronal survival in hippocampal CA1 region of ovariectomized rats. Glucocorticoid receptor (GR) is a member of the adrenal steroid hormone receptor, which is highly expressed in the rat hippocampus. Activation of the GR plays a critical role in the neuronal stress responses, including ischemic brain damage. This study therefore examined the potential mechanisms by which genistein regulates GR signaling, including the protein distribution and receptor activation in hippocampus following ischemic reperfusion (I/R). Results showed that GR expression in the ovariectomized rats was excessively increased both in neurons (I/R 6h) and activated microglial cells (I/R 7d) in hippocampal CA1 region. Genistein treatment significantly attenuated GR induction and the enhanced GR nuclear translocation and DNA-binding capacity. The effects of genistein on the GR levels was accompanied with decreased blood plasma levels of corticosterone (primary glucocorticoid in rodents) and coupled to an E3 ubiquitin ligase Mdm2 targeted proteasomal degradation of GR, because genistein treatment could enhance the GR–Mdm2 interaction and the ubiquitination level of GR protein. In addition, our results indicated that genistein markedly prevented the excessive activation of microglia in CA1 sector. These results demonstrate the neuroprotective action of chronic low dose genistein replacement against ischemic brain damage, and a potential mechanism associated with the inhibition of both neuronal and microglial GR signaling following ischemic stress.

Soy isoflavone phase II metabolism differs between rodents and humans: implications for the effect on breast cancer risk

Human and animal studies have produced conflicting results with regard to the effect of soy isoflavones on breast cancer risk. This may be due to differences in isoflavone metabolism. The objective of this study was to determine whether soy isoflavone phase II metabolism differs between humans and rodents. Circulating total and unconjugated isoflavone concentrations were determined by mass spectrometry in plasma samples from 7 separate studies: 1) in Sprague-Dawley rats and in 3 strains of mice fed commercial soy-containing diets; 2) in Sprague-Dawley rats gavaged with genistein; 3) in healthy adults who consumed single servings of soy nuts, soy milk, and tempeh; 4) in healthy adults subchronically given soy milk; 5) in healthy women orally administered 50 mg genistein; 6) in healthy women orally administered 20 mg pure S-(-)equol; and 7) in 6-mo-old infants fed soy infant formula and later, at age 3 y, a soy germ isoflavone supplement. The proportion of unconjugated genistein in plasma from adults and infants who consumed different soy foods, pure genistein, or an isoflavone supplement was <1% in steady state and <2% at peak concentrations. By contrast, rodents fed soy-containing diets conjugate isoflavones less efficiently. The plasma percentages of unconjugated genistein concentrations in Sprague-Dawley rats and C57BL/6, nude, and transgenic AngptL4B6 mice were 4.0 ± 0.6%, 4.6 ± 0.6%, 11.6 ± 0%, and 30.1 ± 4.3%, respectively, which represent 20, 23, 58, and 150 times that in humans. The markedly higher circulating concentrations of biologically active (unconjugated) genistein in certain strains of mice cast doubt on the value of the use of these rodents for gaining insight into the effects of isoflavones in humans, especially with regard to the effects on breast tissue.

In Vitro Evaluation of Antioxidant and Anti-Inflammatory Properties of Genistein-Modified Hemodialysis Membranes

Genistein-modified poly(amide):poly(vinyl pyrrolidone) (PA:PVP/G) hemodialysis membranes have been fabricated by coagulation via solvent (dimethyl sulfoxide, DMSO)/nonsolvent (water) exchange. The antioxidant and anti-inflammatory properties of the unmodified PA:PVP membranes were evaluated in vitro using human blood. It was found that these unmodified PA:PVP membranes were noncytotoxic to peripheral blood mononuclear cells (PBMC) but raised intracellular reactive oxygen species (ROS) levels. Pure genistein (in DMSO solution) was not only nontoxic to PBMC, but also suppressed the ROS levels in a manner dependent on genistein dosage. A similar dose-dependent suppression of ROS was found in genistein-modified PA (i.e., PA/G) membranes. However, the PVP addition had little or no effect in the suppression of ROS levels for the ternary PA:PVP/G system; the membrane ROS suppression was largely controlled by the genistein dosage. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin (IL-6) in whole blood were measured by ex vivo stimulation with lipopolysaccharide (LPS). The unmodified PA:PVP membranes drastically increased the level of TNF-α; however, the concentration of IL-1β and IL-6 remained almost the same. The PA/G membranes reduced the concentration of IL-1β and TNF-α even at very low genistein loadings, but it required a higher genistein loading to realize a similar effect in the case of IL-6. Of particular importance is that the genistein-modified blend membranes (PA:PVP/G) showed greater suppression of the concentrations of all three cytokines (TNF-α, IL-1β, and IL-6) in comparison with those of the PA/G membranes, signifying the role of PVP in the enhanced anti-inflammatory properties of these genistein-modified membranes. Ultraviolet-visible (UV-vis) spectroscopy was employed to quantify any genistein leaching during the in vitro testing.

Soy-derived phytoestrogens as preventive and acute neuroprotectors in experimental ischemic stroke: Influence of rat strain

The ability of a soy-based high-phytoestrogen diet (nutritional intervention) or genistein (pharmacological intervention), to limit ischemic brain damage in Wistar, Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats, has been assessed. As to the nutritional intervention, two groups from each strain received either a phytoestrogen-free (PE-0) or a high-phytoestrogen (PE-600) diet from weaning to adulthood. As to the pharmacological intervention, all animals were fed the standard soy-free AIN-93G diet and subsequently separated into two groups from each strain to receive either pure genistein (aglycone form, 1mg/kg/day intraperitoneal) or vehicle at 30 min reperfusion. After an episode of 90 min ischemia (intraluminal thread procedure) followed by 3 days reperfusion, cerebral infarct volume was measured. Arterial blood pressure (ABP) was significantly higher at the basal stage (just before ischemia) in SHR (140 ± 7 mmHg, n=17, p<0.05) than in Wistar (113 ± 4mmHg, n=23) and WKY (111 ± 6mmHg, n=14) rats. No significant differences were shown among the three stages (basal, ischemia, reperfusion) within each rat strain for both PE-0 and PE-600 diets. Wistar, but not WKY or SHR, rats fed the PE-600 diet showed significantly lower infarct volumes than their counterparts fed the PE-0 diet (30 ± 3% vs. 17 ± 3%, p<0.01). Genistein-treated Wistar, but not WKY or SHR, rats showed significantly lower infarct volumes than their vehicle-treated controls (27 ± 2% vs. 15 ± 2%, p<0.01). Our results demonstrate that: (1) the neuroprotective action of either chronic or acute exposure to soy isoflavones is strain-dependent, since it was shown in Wistar but not WKY or SHR rats; and (2) the soy-based diet does not prevent development of hypertension in SHR rats.

Genistein Alters the Release of Oxytocin, Prostaglandins, Cortisol and LH during Insemination in Gilts

Soya products containing phytooestrogens are widely used as feed for pigs. However, limited data are available on the effects of phytooestrogen on the endocrine status of pigs. The aim of this work was to study the impact of the phytooestrogen genistein added to a soya-free diet on the hormonal pattern in gilts during oestrus and artificial insemination (AI). Ten gilts were fed a soya-free diet and fitted with jugular vein catheter through vena auricularis. The gilts were randomly divided into two groups (G- and C-group) where the G-group was given pure genistein, 1 mg/kg body weight (BW) twice daily, per os. Blood samples were collected before, during and after AI. Oxytocin, prostaglandin E₂, prostaglandin F₂(α), 13,14-dihydro-15-keto-prostaglandin F₂(α) (PGFM), cortisol and LH concentrations in blood plasma were analysed. Oxytocin concentrations were almost twice as high in the G-group as in C-group after the AI. Prostaglandin E₂ concentrations were higher in G-group than in C-group during the entire sampling period. After AI, the concentrations of prostaglandin E₂ increased in G-group but not in C-group. Prostaglandin F₂(α) concentration had a pulsatile pattern, with increasing pulses after AI in G-group. Plasma PGFM concentrations increased after AI with a small variation between the groups. Plasma cortisol concentration increased after AI in C-group. LH decreased after AI in G-group. Genistein stimulated elevations of plasma oxytocin and prostaglandin E₂ concentrations and a pulsative pattern in prostaglandin F₂(α) concentration. The possible involvement of genistein in plasma cortisol and basal LH concentrations in gilts given genistein may also be suggested.

Abstract 5541: Daidzein protects against genistein-induced lymph node metastasis, and serve as a radiosensitizer in prostate cancer

Abstract We have previously reported that genistein, the major bioactive isoflavone of soybeans, acts as a radiosensitizer for prostate cancer (PCa) both in vitro and in orthotopic mouse models in vivo. However, pure genistein promoted increased spontaneous metastasis to regional lymph nodes, when administered alone in vivo. In contrast to genistein, a natural formulation of soy isoflavones mixture (43% genistein, 21% daidzein and 2% glycitein) did not cause increased metastasis, but like genistein, the soy mixture potentiated the therapeutic effect of radiation. We have now tested whether daidzein, the second main isoflavone of soybeans, could negate genistein-induced lymph node metastasis in PC-3 orthotopic prostate tumors in nude mice. Mice were treated with purified daidzein, or genistein or both combined; and also in conjunction with prostate tumor irradiation. Either daidzein or genistein alone or both combined caused the same extent of prostate tumor growth inhibition than the soy mixture. Treatment with daidzein alone did not increase metastasis to regional lymph nodes but still acted as a potent radiosensitizer for prostate tumors. Treatment with both genistein and daidzein combined did not cause an increase in lymph node metastasis, which is consistent with the findings obtained with the soy mixture. These studies show that pure daidzein could be the component of the soy isoflavones mixture that protects against genistein-induced lymph node metastasis. In order to gain further mechanistic insight on how daidzein negates the adverse effects of genistein, we compared the effects of each isoflavone and the soy mixture in vitro using PC-3 (androgen receptor AR-) and C4-2B (AR+) androgen independent PCa cell lines. We found that daidzein inhibited tumor cell growth and synergized with radiation in clonogenic assays but at doses higher than genistein or the soy mixture. We have previously demonstrated that genistein or the soy mixture cause tumor cell apoptosis and enhance radiation killing by inhibiting cell survival pathways activated by radiation including the repair enzyme/redox activator APE1/Ref-1 and the transcription factors HIF-1α and NF-κB. Compared to the effect of genistein or the soy mixture, daidzein treatment caused milder effects on PARP cleavage, inhibition of expression of APE1/Ref-1 and HIF-1α; and lower inhibition of HIF-1α and NF-κB DNA binding activities. These effects were reproduced in both PC-3 and C4-2B cell lines. Based on these results, we conclude that APE1/Ref-1, NF-κB and HIF-1α molecular pathways were also affected by daidzein, although to a lesser extent than genistein and soy mixture, in both AR+ and AR- PCa cancer cell lines, suggesting that this is an AR-independent mechanism. The protective effect of daidzein against lymph node metastasis induced by genistein appears to be independent of HIF-1α and NF-κB pathways, and remains to be clarified. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5541.

Daidzein Effect on Hormone Refractory Prostate Cancer In Vitro and In Vivo Compared to Genistein and Soy Extract: Potentiation of Radiotherapy

Genistein, the major bioactive isoflavone of soybeans, acts as a radiosensitizer for prostate cancer (PCa) both in vitro and in vivo. However, pure genistein promoted increased metastasis to lymph nodes. A mixture of soy isoflavones (genistein, daidzein, glycitein) did not cause increased metastasis, but potentiated radiotherapy. We tested whether daidzein could negate genistein-induced metastasis. Mice bearing PC-3 prostate tumors were treated with daidzein, genistein or both, and with tumor irradiation. Primary tumors and metastases were evaluated. The effects of each isoflavone and soy were compared in vitro using PC-3 (AR-) and C4-2B (AR+) androgen-independent PCa cell lines. Daidzein did not increase metastasis to lymph nodes and acted as a radiosensitizer for prostate tumors. Daidzein inhibited cell growth and enhanced radiation in vitro but at doses higher than genistein or soy. Daidzein caused milder effects on inhibition of expression and/or activities of APE1/Ref-1, HIF-1alpha and NF-kappaB in PC-3 and C4-2B cells. Daidzein could be the component of soy that protects against genistein-induced metastasis. Daidzein inhibited cell growth and synergized with radiation, affecting APE1/Ref-1, NF-kappaB and HIF-1alpha, but at lower levels than genistein and soy, in AR+ and AR- PCa cells, suggesting it is an AR-independent mechanism.

Effect of genistein therapy on plasma levels of asymmetric dimethylarginine in healthy postmenopausal women: a randomized, placebo-controlled study

The aim of this study was to investigate the effects of pure genistein therapy on asymmetric dimethylarginine in healthy postmenopausal women. Healthy postmenopausal women received pure genistein (n=21) or placebo (n=17) for 6 months, and no statistically significant effects on plasma asymmetric dimethylarginine levels were found with pure genistein treatment.

Acute and Chronic Exposure to Phytoestrogens Disrupts Ovarian Follicle Maturation in Sprague-Dawley Rats.

The consumption of dietary phytoestrogens, such as isoflavones, has grown increasingly popular due to their potential health benefits. These soy products contain the isoflavones genistein, diadzein, and glycitein, which belong to a class of non-steroidal estrogen-like compounds called phytoestrogens. These naturally occurring plant estrogens may provide health-related benefits in some tissues; however, they may present deleterious side effects on estrogen-sensitive reproductive tissue such as the developing ovary. Several studies have documented that an in-utero and lactational exposure to estrogenic chemicals alters normal reproductive tissue development. This study was designed to determine (1) if an in-utero, lactational and chronic exposure to a low or high dose of a mixed isoflavone supplement (LSup and HSup) or a low dose of pure genistein (Gen) exerts detrimental effects on ovarian follicle maturation in the Sprague-Dawley rat; (2) whether estrogen concentrations are altered following acute or chronic exposure; and (3) whether estrous cycles are modulated during chronic exposure. Animals receiving an acute exposure were treated in utero and lactationally from gestational day 7 through postnatal day 28 (weaning). Animals receiving a chronic exposure were treated directly for an additional 65 days. Acute- and chronic-exposure groups were treated daily via oral gavage (LSup, HSup) or subcutaneous injection (Gen). LSup and HSup treatment groups received 2.4 mg/kg/day or 24 mg/kg/day, respectively. The Gen treatment group received 0.2 mg/kg/day. Acutely exposed pups were sacrificed on postnatal day 28 (chosen in order to follow the pups' exposure through lactation). Chronically exposed rats were sacrificed on postnatal day 93. Following sacrifice, the ovaries were excised, fixed for histology, and analyzed. The analysis included a count, and measurement and classification of preantral and antral follicles in the greatest cross-sectional area of the ovary. Blood samples collected at the time of sacrifice were analyzed for estrogen concentrations via radioimmunoassay. No statistical change in estrogen concentrations was noted among acute-treatment groups. Radioimmunoassay results for the chronically exposured groups indicated a significant difference in estrogen concentration between the control group and the other three treatment groups (p<0.001). For both the acute- and chronic-treatment groups, atresia levels and follicular count remained consistent in the control, LSup, and Gen treatment groups; however, increased atresia and decreased follicles were observed in the HSup treatment groups (p<0.05). Modulation of estrous cycles was noted in all four chronic treatment groups. These data support the hypothesis that isoflavones reduce the number of follicles of certain size classes in rats exposed during the critical period of development and during chronic exposure after birth. Atresia of antral follicles may constitute one of the underlying mechanisms by which folliculogenesis is modulated by phytoestrogens. The results of this study begin to elucidate the acute and chronic effects of a soy phytoestrogen on reproductive parameters in the female Sprague-Dawley rat. (platform)

Differential effect of pure isoflavones and soymilk on estrogen receptor activity in mice

Background Because of the complexity of estrogen receptor (ER) physiological activity, the interaction of pure isoflavones or soy-based diets on ER needs to be clearly demonstrated. Objectives To investigate the effects of the administration of isoflavones as a pure compound or as a component of diet on the ER transcriptional activity in adult mice. Methods Effects of acute (6 h) and chronic (21 days) oral administration of soy milk, pure genistein and a mix of genistein and daidzein was studied in living ERE-Luc mice. In this animal model, the synthesis of luciferase is under the state of ER transcriptional activity. Luciferase activity was measured in living mice by daily bioluminescence imaging sessions and in tissue extracts by enzymatic assay. Results Acute, oral administration of genistein or soymilk caused a significant increase of ER activity in liver. In a 20 day long treatment, soymilk was more potent than genistein in liver and appeared to extend its influence on ER transcriptional activity in other tissues, such as the digestive tract. A mixture of pure genistein and daidzein at the same concentration as in soymilk failed to induce significant changes during acute and chronic studies suggesting an important, uncharacterized role of the soymilk matrix. Consistent with this observation, synergistic effects of the matrix plus isoflavones were observed in MCF-7 cells stably transfected with the ERE-luc construct. Conclusions This study underlines the limitations of the analysis of single food components in the evaluation of their effects on estrogen receptor activity and advocates the necessity to use complex organisms for the full comprehension of the effects of compounds altering the endocrine balance.