Alfalfa & Coumestrol Exposure
Findings: Alfalfa contained 25–65 ppm coumestrol on a dry-matter basis, along with smaller quantities of formononetin and biochanin A. When estrogenic activity of the forage was tested biologically using uterine weight in immature rats, alfalfa produced an observable estrogenic response.
Phytoestrogen content and estrogenic effect of legume fodder
DOI: 10.3181/00379727-208-43825
DOI URL: https://doi.org/10.3181/00379727-208-43825
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Alfalfa Phytoestrogen Concentration
Findings: Field-grown alfalfa contained measurable coumestrol, apigenin, luteolin, and quercetin. Concentrations of individual phytoestrogens in whole herbage ranged from approximately 15 to 225 μg/g dry matter and varied substantially with plant maturity.
Alfalfa Phytoestrogen Content: Impact of Plant Maturity and Herbage Components
DOI: 10.1111/j.1439-037X.2004.00100.x
DOI URL: https://doi.org/10.1111/j.1439-037X.2004.00100.x
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Alfalfa & Estrogen-Receptor Activation
Findings: Alfalfa sprouts contained multiple compounds capable of estrogen-receptor activation, including coumestrol, liquiritigenin, isoliquiritigenin, and additional identified compounds. Most showed greater transactivation through ERβ than ERα. Maximum ERα activation by coumestrol reached approximately 80% of the activation produced by 1 nM 17β-estradiol under the study conditions.
Phytoestrogenic Compounds in Alfalfa Sprout (Medicago sativa) beyond Coumestrol
DOI: 10.1021/jf102997p
DOI URL: https://doi.org/10.1021/jf102997p
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Alfalfa Coumestrol Variability
Findings: Coumestrol concentration in alfalfa varied with development and biological stressors, including fungal disease. The study found that contemporary alfalfa cultivars could still produce coumestrol concentrations considered detrimental to ewe reproductive performance.
Alfalfa Coumestrol Content in Response to Development Stage, Fungi, Aphids, and Cultivar
DOI: 10.2134/agronj2017.09.0535
DOI URL: https://doi.org/10.2134/agronj2017.09.0535
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Soybean Isoflavone Content
Findings: Soybean plants and seeds contained multiple isoflavone aglycones and glycosides, including genistein, genistin, daidzein, daidzin, glycitein, and glycitin. Among the soybean varieties examined, concentrations in beans varied substantially, reaching approximately 3–1,100 μg/g fresh weight.
Evaluation of Isoflavone Aglycon and Glycoside Distribution in Soy Plants and Soybeans by Fast Column High
Performance Liquid Chromatography Coupled with a Diode-Array Detector
DOI: 10.1021/jf0502754
DOI URL: https://doi.org/10.1021/jf0502754
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Soy Foods & Isoflavone Concentration
Findings: Analysis of soy foods identified genistein, daidzein, glycitein, and their conjugates. Mean total isoflavone concentrations ranged from approximately 35 to 7,500 ppm depending on the soy product, soybean variety, storage conditions, water content, and processing method.
Isoflavone Levels in Soy Foods Consumed by Multiethnic Populations in Singapore and Hawaii
DOI: 10.1021/jf9808832
DOI URL: https://doi.org/10.1021/jf9808832
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Soy Isoflavones & Estrogenic Activity
Findings: Genistein, daidzein, and glycitein competed with estradiol for estrogen-receptor binding. In immature female mice, four days of glycitein exposure increased uterine weight by 150%, while genistein increased uterine weight by 50% relative to controls. The authors characterized glycitein as estrogenically active, although considerably less potent than 17β-estradiol.
Estrogenic Activity of Glycitein, a Soy Isoflavone
DOI: 10.1021/jf981054j
DOI URL: https://doi.org/10.1021/jf981054j
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Soy and Alfalfa Diets & Reproductive Development
Findings: A conventional natural-ingredient rodent diet containing soy and alfalfa provided 16 mg genistein and 14 mg daidzein per 100 g of feed, while the experimental soy- and alfalfa-free diet contained no detectable isoflavones. Genistein and daidzein were complete agonists at both ERα and ERβ in vitro and were more potent at ERβ. High dietary genistein exposure produced a 2.3-fold increase in uterine-to-body-weight ratio and accelerated female puberty. At the lower phytoestrogen concentrations present in the conventional diet, effects were substantially smaller, although female neonatal anogenital distance differed significantly from the soy- and alfalfa-free group.
Developmental effects of dietary phytoestrogens in Sprague-Dawley rats and interactions of genistein and daidzein
with rat estrogen receptors alpha and beta in vitro
DOI: 10.1093/toxsci/51.2.236
DOI URL: https://doi.org/10.1093/toxsci/51.2.236
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Developmental Soy Isoflavone Exposure & Leydig Cell Function
Findings: Rats exposed during gestation and lactation to diets containing soy isoflavones showed dose-dependent alterations in testicular steroid physiology. At 1,000 ppm dietary isoflavones, biologically active genistein and daidzein were measurable in offspring, Leydig-cell steroidogenesis was reduced, and adult serum testosterone was elevated. Direct exposure of isolated immature Leydig cells to 0.1 nM genistein reduced testosterone secretion from 175 ± 5 to 117 ± 3 ng/10⁶ cells per 24 hours.
Exposure to Phytoestrogens in the Perinatal Period Affects Androgen Secretion by Testicular Leydig Cells in the
Adult Rat
DOI: 10.1210/en.2007-0327
DOI URL: https://doi.org/10.1210/en.2007-0327
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Soy Isoflavones & Male Reproductive Endocrinology
Findings: Rats exposed to high-dose genistein and daidzein from prenatal development through sexual maturity developed changes in seminiferous-epithelium morphology. Estradiol concentrations were significantly higher in serum and epididymal tissue, while intratesticular testosterone was significantly lower than in controls. Epididymal sperm numbers were not significantly changed.
Changes in male reproductive system and mineral metabolism induced by soy isoflavones administered to rats
from prenatal life until sexual maturity
DOI: 10.1016/j.nut.2010.03.010
DOI URL: https://doi.org/10.1016/j.nut.2010.03.010
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Coumestrol & Estrogenic Tissue Response
Findings: Coumestrol competitively bound the estrogen receptor and produced uterine growth in rats. Coumestrol remained uterotrophic when incorporated into a semipurified diet at concentrations intended to represent natural dietary exposure, increasing both uterine wet and dry weight. Coumestrol is a major phytoestrogen associated with alfalfa, although this experiment tested coumestrol itself rather than alfalfa as the dietary ingredient.
Effects of a normal, human-concentration, phytoestrogen diet on rat uterine growth
DOI: 10.1016/0039-128X(92)90066-I
DOI URL: https://doi.org/10.1016/0039-128X(92)90066-I
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Soy and Alfalfa Phytoestrogens & Estrogen Receptors
Findings: Coumestrol and genistein bound estrogen receptors and preferentially interacted with ERβ relative to ERα. In estrogen-responsive transcription assays, genistein and coumestrol activated both estrogen-receptor subtypes at concentrations of approximately 1–10 nM. For ERβ, genistein and coumestrol were among the most potent phytoestrogens tested. Daidzein also activated both receptor subtypes but was less potent.
Interaction of Estrogenic Chemicals and Phytoestrogens with Estrogen Receptor β
DOI: 10.1210/endo.139.10.6216
DOI URL: https://doi.org/10.1210/endo.139.10.6216
