EGFR; topo II

Genistein exhibits chemopreventive effects on tumors that are endocrine-dependent, including those of the breast and prostate in adult animals. In a dose-dependent manner, genistein in the diet decreased the incidence of poorly differentiated prostatic adenocarcinomas and down-regulated the mRNA expressions of the progesterone receptor, estrogen receptor-alpha, androgen receptor, prodermal growth factor receptor, insulin-like growth factor-I, and extracellular signal-regulated kinase-1, but not those of the estrogen receptor-beta and transforming growth factor-alpha. By controlling particular sex steroid receptors and growth factor signaling pathways, dietary genistein guards against prostate and breast cancers.[4] In order to increase mouse survival, genistein combined with prostate tumor irradiation causes a greater inhibition of primary tumor growth and increases control of spontaneous metastasis to para-aortic lymph nodes. It is paradoxical that genistein therapy alone promotes lymph node metastasis.[5]

Absorption, Distribution and Excretion
... Genistein is rapidly absorbed in humans following oral intake. Before absorption into the systemic circulation, most genistein is conjugated with glucuronic acid and excreted in the bile to undergo enterohepatic circulation ... . Therefore, genistein bioavailability is very limited. Times to obtain maximum plasma concentrations were reported at 1 to 6 hours for free genistein ... and 3 to 8 hours for total genistein (aglycone + conjugates ...). In one of the studies, the lowest dose used (2 mg/kg bw) was stated to provide more than twice the level of isoflavones ingested in a Japanese daily diet. A study in which menopausal women were given a 50 mg commercial isoflavone extract incorporated into fruit juice, chocolate, or a cookie showed no significant effect of the food matrix on genistein absorption or urinary excretion parameters. In a study in which 8 women were dosed with 0.4 or 0.8 mg/kg bw 13C-labeled genistein, the area under the curve (AUC) at the higher dose was less than double the AUC at the lower dose, suggesting a decrease in fractional absorption with increasing dose.
There is considerable individual variation in the absorption and metabolism of ingested genistin and genistein. There are some data suggesting that genistein may be more bioavailable than genistin. However, other data suggest that the extent of absorption of genistein is similar for the aglycone and the glucoside forms. There are little data available on the tissue distribution of genistein.
A recently completed study has also shown inter-individual variation in the urinary excretion of isoflavones and their metabolites following soy challenge in adults. In this study, 76 volunteers were fed either a high (104+/-24 mg total isoflavones/day) or low (0.5+/-0.5 mg total isoflavones/day) soya diet for 10 weeks. Volunteers on the high soya diet showed extensive urinary excretion of daidzein, genistein and their metabolites. Of the volunteers on the high soya diet 34% were identified as good equol excretors ( 1000 nmol/24 hours). Comparative analysis of the fecal flora between equol and non-equol producers was investigated, however, the microflora (bacteria) responsible for equol production could not be isolated and therefore, were not be identified
The pharmacokinetics of isoflavones in 10 healthy women were determined from serum appearance/disappearance concentration profiles and urinary excretions after single-bolus ingestion of 10, 20 or 40 g of soy nuts delivering increasing amounts of the conjugated forms of daidzein (6.6, 13.2 and 26.4 mg) and genistein (9.8, 19.6 and 39.2 mg). Peak serum daidzein and genistein concentrations were attained after 4-8 hr, and elimination half-lives were 8.0 and 10.1 hr, respectively. There were no differences in the pharmacokinetics of daidzein and genistein between pre- and postmenopausal women, indicating absorption and disposition of isoflavones to be independent of age or menopausal status. A curvilinear relationship was observed between the bioavailability of daidzein and genistein, apparent from the area under the curve to infinity (AUC(inf)) of the serum concentration-time profiles and the amount of isoflavones ingested. The mean fraction of the isoflavones excreted in urine decreased with increasing intake when expressed as a percentage of the administered dose (63.2 + or - 8.0, 54.4 + or - 8.1 and 44.0 + or - 4.3%, respectively, for daidzein, and correspondingly, 25.2 + or - 5.3, 13.4 + or - 2.1 and 15.8 + or - 2.7% for genistein), underscoring the trend toward nonlinear pharmacokinetics. Equol was identified as a metabolite in 30% of women; it was present consistently in urine and blood from the same subjects. Its delayed appearance was consistent with colonic synthesis. On the basis of the pharmacokinetics, optimum steady-state serum isoflavone concentrations would be expected from modest intakes of soy foods consumed regularly throughout the day rather than from a single highly enriched product.
For more Absorption, Distribution and Excretion (Complete) data for GENISTEIN (15 total), please visit the HSDB record page.

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Metabolism / Metabolites
Toxicokinetic and metabolism data in humans and experimental animals indicate that genistein is absorbed into the systemic circulation of infants and adults. Genistein ... circulates as its glucuronide conjugate, and a much smaller percentage circulates as the aglycone. Genistein can be glucuronidated in the intestine or liver, but the intestine appears to play the major role in glucuronidation. Genistein glucuronides undergo enterhepatic cycling, and in the process can be deconjugated by intestinal bacteria. The role of gut bacteria in the metabolism of genistein has been clearly established. Genistein can be metabolized through a pathway that ultimately leads to the formation of 6'-hydroxy-O-demethylangolensin. Once absorbed, genistein glucuronide, and to a smaller extent genistien aglycone, are widely distributed to organ systems and the conceptus. The majority of a genistein dose is excreted in urine within 24 hours.
Prior to entering the systemic circulation, most genistein is conjugated with glucuronic acid by uridine diphosphate (UDP)-glucuronosyltransferase (UDPGT); a much smaller amount is conjugated to sulfate by sulfotransferase enzymes. Conjugation of genistein occurs in the intestine, although it also has been reported to occur in liver. One study demonstrated that the ability to catalyze glucuronidation of genistein was greatest with microsomes from kidney > colon > liver. UDPGT isoenzymes including 1A1, 1A4, 1A6, 1A7, 1A9, and 1A10 were observed to catalyze the glucuronidation of genistein. The UGT 1A10 isoform, which is present in colon, gastric, and biliary epithelium but not in liver, was observed to have the highest activity and specificity for genistein. Based on those observations, the study authors concluded that the intestine plays a major role in the glucuronidation of genistein. The glucuronide and sulfate conjugates can enter the systemic circulation, and the majority of isoflavone compounds in the circulation are present in conjugated form. In studies where humans were exposed to genistein alone or in combination with other isoflavone aglycones (calculated as genistein doses of 1-16 mg/kg bw), most of the genistein was present in plasma in conjugated form; free genistein represented 1-3% of total plasma genistein levels. The conjugated isoflavones undergo enterohepatic circulation, and upon return to the intestine, they are deconjugated by bacteria possessing beta-glucuronidase or arylsulfatase activity. The metabolites may be reabsorbed or further metabolized by gut microflora. One review reported that about 10% of isoflavonoids are circulated in plasma unconjugated.
Biotransformations by gut microflora play a pivotal role in determining the biological activity of isoflavones that occur in soya-based foods predominantly as betaglycosyl conjugates. Microflora prepared from rat caeca and human feces were used to investigate the metabolic fate of genistein beta-glycosides extracted from soya flour. The end-products of such metabolism were determined by parallel incubations of microflora with [2',3,5',6'-3H] and [4-14C]-labelled genistein. ... Quantitative analysis by LC-MS/IS indicated very rapid and complete degradation of genistin, which was associated with a transient increase in genistein. Qualitative studies indicated that the malonyl and acetyl glycosides of genistein were also degraded by the microflora. ... Incubation of caecal and fecal microflora with (3)H and (14)C genistein yielded similar radiolabelled metabolites, which were identified by radio-LC-MS(n) as the intermediates dihydrogenistein and 6'-hydroxy-O-desmethylangolensin and end-product 4-hydroxyphenyl-2-propionic acid. This profile of genistein metabolites indicated selective hydrolysis of 6'-hydroxy-O-desmethylangolensin between carbon atoms 1' and 1 to yield the end-products 4-hydroxyphenyl-2-propionic acid and 1,3,5-trihydroxybenzene. ... The biological significance of the products of genistein metabolism warrant further investigation since they may play an important role in mediating the beneficial antioxidant health effects associated with the consumption of isoflavones in food.
Biotransformation of the phytoestrogen (14-C)genistein was investigated in male and female rats by application of narrow-bore radio-HPLC-MSn (LCQ, Finnigan) to determine intermediates in metabolism. Urine contained five metabolites, Gm1-Gm5, 24 hr after dosing by gavage with [14C]genistein (4 mg kg(-1)). Structural analysis following ESI revealed molecular ions (M+H)+ of m/z 447, 449, 273, and 271 for metabolites Gm2, Gm3, Gm5 and genistein, respectively and an [M-H]- of m/z 349 for Gm4. Metabolite structure was deduced by evaluation of product ion spectra derived from unlabelled and (14)C-labelled ions and sensitivity to treatment with beta-glucuronidase. These studies indicated identity of metabolites with genistein glucuronide (Gm2), dihydrogenistein glucuronide (Gm3), genistein sulphate (Gm4) and dihydrogenistein (Gm5). Detection of the beta-glucuronidase resistant major metabolite Gm1 by ESI was poor and so was analysed by negative ion APCI; this revealed a deprotonated molecular ion of m/z 165 which had chromatographic and mass spectral properties consistent with authentic 4-hydroxyphenyl-2-propionic acid, a novel metabolite of genistein. In vitro metabolism studies with anaerobic caecal cultures derived from male and female rats revealed metabolism of genistein to Gm1 via Gm5 and an additional metabolite (Gm6) which was identified from product ion spectra as 6'-hydroxy-O-desmethylangolensin. Biotransformation of genistein by both isolated hepatocytes and precision-cut liver slices was limited to glucuronidation of parent compound. Commonality of genistein metabolites found in rats with those reported in man suggest similar pathways of biotransformation, primarily involving gut micro-flora.
For more Metabolism/Metabolites (Complete) data for GENISTEIN (7 total), please visit the HSDB record page.
Genistein has known human metabolites that include Dihydrogenistein, (2S,3S,4S,5R)-3,4,5-Trihydroxy-6-[5-hydroxy-3-(4-hydroxyphenyl)-4-oxochromen-7-yl]oxyoxane-2-carboxylic acid, and Orobol.
Genistein is a known human metabolite of biochanin a.

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Biological Half-Life
... Thirty healthy men ingested a single dose of 1 of 2 isoflavone preparations purified from soy. The delivered doses of genistein (1, 2, 4, 8, or 16 mg/kg body wt) were higher than those previously administered to humans. Formulation A was composed of 90 +/- 5% genistein, 10% daidzein, and 1% glycitein. Formulation B was composed of 43% genistein, 21% daidzein, and 2% glycitein. ... The mean elimination half-lives with both formulations were 3.2 hr for free genistein and 4.2 hr for free daidzein. The mean pseudo half-lives were 9.2 hr for total genistein and 8.2 hr for total daidzein.
The pharmacokinetics of isoflavones in 10 healthy women were determined from serum appearance/disappearance concentration profiles and urinary excretions after single-bolus ingestion of 10, 20 or 40 g of soy nuts delivering increasing amounts of the conjugated forms of daidzein (6.6, 13.2 and 26.4 mg) and genistein (9.8, 19.6 and 39.2 mg). Peak serum daidzein and genistein concentrations were attained after 4-8 hr, and elimination half-lives were 8.0 and 10.1 hr, respectively.
Mass balance, plasma pharmacokinetics, tissue distribution, and metabolism of (14-C)genistein were investigated in male and female rats (n = 5) following an oral dose of (14-C)genistein (4 mg/kg) to determine potential sites and mechanisms of biological action. Mean total excretion of radioactivity in urine and feces for both sexes was 66 and 33% of the dose respectively at 166 hr after administration. Mean and maximal concentrations of radioactivity in plasma were significantly (P < 0.02) higher in male than female rats, with half-lives of 12.4 and 8.5 hr, respectively.

Toxicity Summary
Genistein may inhibit cancer cell growth by blocking enzymes required for cell growth.

Genistein may decrease cardiovascular risk in postmenopausal women by interacting with the nuclear estrogen receptors to alter the transcription of cell specific genes. In randomized clinical trials, genistein was seen to increase the ratio of nitric oxide to endothelin and improved flow-mediated endothelium dependent vasodilation in healthy postmenopausal women. [1] In addition, genistein may have beneficial effects on glucose metabolism by inhibiting islet tyrosine kinase activity as well as insulin release dependent on glucose and sulfonylurea. [1]

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Interactions
Humans and wildlife are frequently exposed to mixtures of endocrine active-compounds (EAC). The objective of the present study was to investigate the potential of the phytoestrogen genistein to influence the reproductive developmental toxicity of the endocrine-active pesticide methoxychlor. Three levels of genistein (0, 300, or 800 ppm) and two levels of methoxychlor (0 or 800 ppm) were used in this study. Sprague-Dawley rats were exposed to the two compounds, either alone or in combinations, through dietary administration to dams during pregnancy and lactation and to the offspring directly after weaning. Both compounds, methoxychlor in particular, were associated with reduced body growth at 800 ppm, but pregnancy outcome was not affected by either treatment. An acceleration of vaginal opening (VO) in the exposed female offspring was the only observed effect of genistein at 300 ppm. Exposure to 800 ppm genistein or 800 ppm methoxychlor caused accelerated VO and also altered estrous cyclicity toward persistent estrus in the female offspring. The estrogenic responses to genistein and methoxychlor administered together were apparently accumulative of the effects associated with each compound alone. Methoxychlor, but not genistein, delayed preputial separation (PPS) in the male rats. When administered with methoxychlor, genistein at 800 ppm enhanced the effect of methoxychlor on delaying PPS. Genistein and methoxychlor treatment did not change gender-specific motor activity patterns in either sex. To explore possible mechanisms for interaction between the two compounds on development, we performed estrogen receptor (ER)- and androgen receptor (AR)-based in vitro transcriptional activation assays using genistein and the primary methoxychlor metabolite 2,2-bis-(p-hydroxyphenyl)-1,1,1-trichloroethane (HPTE). While the in vitro assays supported the estrogenic effects of genistein and methoxychlor and the antiandrogenic effects of methoxychlor, the reactivity of these compounds with ERs alpha and beta could not predict the greater in vivo estrogenic potency of methoxychlor over genistein; nor could the potentiation of the methoxychlor effect on PPS by genistein be predicted based on in vitro HPTE and genistein reactions with the AR. Data from this study indicate that phytoestrogens are capable of altering the toxicological behaviors of other EACs, and the interactions of these compounds may involve complexities that are difficult to predict based on their in vitro steroid receptor reactivities.
... Interactions between the soy isoflavone, genistein, and an antiestrogen, tamoxifen (TAM), on the growth of estrogen (E)-dependent breast cancer (MCF-7) cells implanted in ovariectomized athymic mice /were investigated/. ... Six treatment groups were used: control (C); 0.25 mg estradiol (E2) implant (E); E2 implant + 2.5 mg TAM implant (2.5 TE); E2 implant + 2.5 mg TAM implant + 1000 ppm genistein (2.5 TEG); E2 implant + 5 mg TAM implant (5 TE), and E2 implant +5 mg TAM implant +1000 ppm genistein (5 TEG). Treatment with TAM (2.5 TE and 5 TE) suppressed E2-stimulated MCF-7 tumor growth in ovariectomized athymic mice. Dietary genistein negated/overwhelmed the inhibitory effect of TAM on MCF-7 tumor growth, lowered E2 level in plasma, and increased expression of E-responsive genes (e.g., pS2, PR, and cyclin D1). ... Caution is warranted for postmenopausal women consuming dietary genistein while on TAM therapy for E-responsive breast cancer.
The anticancer agent genistein inhibits cell growth of tumor cell lines from various malignancies. ... /The authors/ investigated the effectiveness of combined treatment of ionizing radiation (IR) with genistein on cervical HeLa cells and its possible mechanism. It was found that the inhibitory rate in cells with combined treatment was significantly higher than that of the cells treated with IR or genistein alone. After treatments of IR (4 Gy) combined with genistein (40 micromol/L), the apoptotic index of the cells was significantly increased and the cells were arrested in the G2/M phase. Survivin mRNA expression increased after IR (4 Gy), while it significantly decreased after combined treatment. These findings indicated that genistein enhanced the radiosensitivity of cervical cancer HeLa cells, and the mechanisms for this action might include increase of apoptosis, decrease of survivin expression, and prolongation of cell cycle arrest.

[1]. J Biol Chem . 1987 Apr 25;262(12):5592-5.

[2]. Biochem Pharmacol . 1990 Jan 1;39(1):187-93.

[3]. J Biol Chem . 2003 Jan 10;278(2):962-7.

[4]. J Nutr . 2002 Mar;132(3):552S-558S.

[5]. Radiat Res . 2006 Jul;166(1 Pt 1):73-80.

Therapeutic Uses
/EXPTL/ Genistein is speculated to provide beneficial effects on cardiovascular and bone health and to alleviate menopausal symptoms; studies examining such endpoints have been limited in number, provided inconsistent findings, or evaluated soy product consumption instead of exposure to genistein alone.
/EXPTL/ Interest in ... /genistein/ is concentrated in particular on its therapeutic role in menopause. This paper is a review of the main studies published to date on the efficacy of phytoestrogens in reducing the symptoms of menopause. A diet rich in isoflavones is associated with a reduced incidence of vasomotor episodes; the average supplement of genistein is approximately 50 mg/day. After supplementing the diet with phytoestrogens, studies show a reduction in total cholesterol and LDL fraction. This is accompanied by an increase in BMD (Bone mineral density) after taking 90 mg of isoflavones for 6 months. Isoflavones may reduce the risk of developing breast cancer. The data examined confirm the excellent clinical efficacy of supplementing the diet with soy extracts, particularly genistein which is indicated to alleviate both the short-term symptoms of menopause and the long-term effects, although the latter finding requires further subsantiation.
/EXPTL/ ... /The authors/ evaluated and compared the effects of the phytoestrogen genistein, estrogen-progestogen therapy (EPT), and placebo on hot flushes and endometrial thickness in postmenopausal women. ... Ninety healthy, postmenopausal women, 47 to 57 years of age, were randomly assigned to receive for 1 year continuous EPT (n = 30; 1 mg 17beta-estradiol combined with 0.5 mg norethisterone acetate), the phytoestrogen genistein (n = 30; 54 mg/day), or placebo (n = 30). Endometrial safety was evaluated by intravaginal ultrasounds at baseline, 6 and 12 months. ... By comparison with placebo, daily flushes reduced significantly by a mean of 22% (95% CI: -38 to -6.2; P < 0.01) after 3 months, by a mean of 29% (95% CI: -45 to -13; P < 0.001) after 6 months, and by a mean of 24% (95% CI: -43 to -5; P < 0.01) after 12 months of genistein treatment. Flush score decreased by a mean of 53% (95% CI: -79 to -26; P < 0.001) after 3 months, by a mean of 56% (95% CI: -83 to -28; P < 0.001) after 6 months, and by a mean of 54% (95% CI: -74 to -33; P < 0.001) after 12 months of EPT, as compared with placebo. No side effect was observed on the uterus of the participants. ... The present study confirms that genistein might have positive effects on hot flushes without a negative impact on endometrial thickness and suggests a future role of this phytoestrogen as a strategically therapeutic alternative in the management of postmenopausal symptoms.
/EXPTL/ There is a growing body of in vitro and animal studies suggesting that genistein may be helpful in preventing and treating some cancers, principally breast and prostate cancers. The clinical studies that might support or refute claims that genistein has anti-atherogenic properties and that it can safely and effectively be used as natural estrogen-replacement therapy have not been conducted. There are, however, preliminary data suggesting that soy isoflavones, including genistein, may be helpful in some problems associated with menopause, including osteoporosis and hot flashes.
For more Therapeutic Uses (Complete) data for GENISTEIN (6 total), please visit the HSDB record page.

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Drug Warnings
Genistein/genistin intake has been associated with hypothyroidism in some.
Women with estrogen receptor-positive tumors should exercise caution in the use of genistein/genistin supplements and should only use them if they are recommended and monitored by a physician.
Men with prostate cancer should discuss the advisability of the use of genistein/genistin supplements with their physicians before deciding to use them.
Pregnant women and nursing mothers should avoid the use of genistein/genistin supplements pending long-term safety studies.
Caution is warranted for postmenopausal women consuming dietary genistein while on tamoxifen therapy for estrogen-responsive breast cancer.

C15H10O5

270.24

270.052

C, 66.67; H, 3.73; O, 29.60

446-72-0

Genistein;446-72-0

5280961

Light yellow to yellow solid powder

1.5±0.1 g/cm3

555.5±50.0 °C at 760 mmHg

297-298 °C

217.1±23.6 °C

0.0±1.6 mmHg at 25°C

1.732

2.96

3

5

1

20

411

0

O1C([H])=C(C2C([H])=C([H])C(=C([H])C=2[H])O[H])C(C2=C(C([H])=C(C([H])=C12)O[H])O[H])=O

TZBJGXHYKVUXJN-UHFFFAOYSA-N

InChI=1S/C15H10O5/c16-9-3-1-8(2-4-9)11-7-20-13-6-10(17)5-12(18)14(13)15(11)19/h1-7,16-18H

5,7-dihydroxy-3-(4-hydroxyphenyl)chromen-4-one

NPI 031L; NPI031L; NPI-031L; BIO-300; G-2535; PTI-G-4660; SIPI-9764-I; PTIG-4660; SIPI-9764I; BIO300; G2535; PTIG4660; SIPI9764I; BIO 300; G 2535; PTI G 4660; SIPI 9764 I; PTIG 4660; SIPI 9764I; Genistein

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 3.75 mg/mL (13.88 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 37.5 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 3 mg/mL (11.10 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 30.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 3 mg/mL (11.10 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 30.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 5 mg/mL (18.50 mM) in 50% PEG300 50% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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 (Please use freshly prepared in vivo formulations for optimal results.)