The identification of the weak oestrogen equol [7-hydroxy-3-(4′-hydroxyphenyl)chroman] in human urine

Axelson, Magnus; Kirk, D. N.; Farrant, R. D.; Cooley, G.; Lawson, A. M.; Setchell, Kenneth D.R.

doi:10.1042/bj2010353

Cited by 229 publications

(96 citation statements)

References 28 publications

(28 reference statements)

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“…These values were statistically different from the animals fed the AIN-diets (p Ͻ 0.001). The bacterially derived metabolite, equol (Axelson et al, 1982;Setchell et al, 1984), was the major isoflavone identified in the serum of all mice fed these three diets and overall accounted for 90% to 97% of the total isoflavones in serum. The serum concentrations in animals fed the Purina 5008 diet was almost twice that of the other two diets.…”

Section: Serum and Urine Isoflavone Concentrations In Adult Mice Fed mentioning

confidence: 99%

“…In both species of rodents equol, not daidzein or genistein, was the major isoflavone in serum and urine. Equol was first isolated from rat urine two decades ago, characterized by mass spectrometry (Axelson et al, 1982;Axelson and Setchell, 1981), and its origin was found to be soy meal used in the manufacture of the rodent chow . It was shown subsequently to be a specific intestinal bacterial metabolite of the soy isoflavones, daidzin and daidzein (Borriello et al, 1985;.…”

Section: Brown and Setchellmentioning

confidence: 99%

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Animal Models Impacted by Phytoestrogens in Commercial Chow: Implications for Pathways Influenced by Hormones

Brown

Setchell

2001

Laboratory Investigation

273

239

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SUMMARY:It is generally not known that most commercial rodent diets are formulated with soy protein and deliver large daily doses of isoflavones to animals throughout their lifespan, including the in utero period. Here, we demonstrate that isoflavones are bioavailable and show that commercial rodent diets universally used by animal facilities lead to very high steady-state serum isoflavone concentrations in adult rats (2613 Ϯ 873 ng/mL) and mice (2338 Ϯ 531 ng/mL), exceeding the animal's endogenous estrogen level by 30,000-to 60,000-fold. We demonstrate the maternal-fetal intrauterine transfer of isoflavones in animals fed a standard Purina 5001 soy-containing diet and show that newborn rat pups have high serum isoflavones levels (540 Ϯ 174 ng/mL) that are maintained throughout the suckling period by passage of isoflavones into maternal milk. These findings have profound implications for all animal experiments, including multigenerational studies and studies of transgenic animals, especially if biochemical or morphological end-points are influenced by the hormonal or nonhormonal properties of phytoestrogens. These compounds have the potential to modulate genotypic and phenotypic expression in general, and therefore, all investigators should be vigilant to the phytoestrogen composition of commercial rodent diets because there is a history of potent biological effects in larger animals and in humans from high circulating isoflavone concentrations. (Lab Invest 2001, 81:735-747).A lthough phytoestrogens are ubiquitous in the plant kingdom, it is soybeans and foods made with purified soy proteins that are by far the greatest contributors of isoflavones to animal and human diets (Coward et

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Section: Serum and Urine Isoflavone Concentrations In Adult Mice Fed mentioning

confidence: 99%

Section: Brown and Setchellmentioning

confidence: 99%

Animal Models Impacted by Phytoestrogens in Commercial Chow: Implications for Pathways Influenced by Hormones

Brown

Setchell

2001

Laboratory Investigation

273

239

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“…Indeed, it is well documented that daidzein can be converted to equol (Eq) or o-desmethylangolensin (O-DMA) by enzymes of bacteria in the intestine (Minamida et al, 2006). Eq was first isolated from pregnant mares' urine in 1932 and was subsequently identified in human urine and in the plasma of sheep derived from daidzein (Marrian and Haslewood, 1932;Axelson et al, 1982). As a metabolite of daidzein, Eq was found to exist in hens' blood and to accumulate dominantly in egg yolk (Saitoh et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

The effect of equol injection in ovo on posthatch growth, meat quality and antioxidation in broilers

Wei

et al. 2011

Animal

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In order to investigate the long-term effects of equol (Eq) on growth and meat quality in broilers, 0 mg (control, Con), 20 mg (low dose, L) and 100 mg (high dose, H) Eq, respectively, were injected into fertile eggs (146 eggs per group) on 7 days of embryos. After hatch, chickens were fed under the same conditions and slaughtered at 49 days of age for sample collection and analysis. The results showed that body weight and composition were marginally affected by Eq administration ( P . 0.05). Compared with their male counterparts, the meat quality of female broilers was affected greatly after Eq administration. The redness (a*) of meat color in the L and H groups of female broilers was significantly decreased by 24.10% and 21.50% ( P , 0.01), respectively; cooking loss decreased by 12.11% and 16.82%, respectively, in the L and H groups ( P , 0.01); 24 h and 48 h drip loss was significantly decreased by 60.27% and 45.72% ( P , 0.05), respectively, in the H group. However, for male broilers, only cooking loss was significantly decreased by high dosage of Eq treatment ( P , 0.05). The antioxidative status was analyzed for discovering further the mechanism behind the improvement of the water-holding capacity caused by Eq in female broilers. The activity of glutathione peroxidase (GSHPx) in plasma was greatly increased by 15.94% in the L group ( P , 0.01), whereas the total superoxide dismutase activity (T-SOD) and the content of malondialdehyde in plasma were not changed ( P . 0.05). The T-SOD activity in the breast muscle of the L and H groups were significantly improved by 23.14% and 18.82% ( P , 0.05), respectively. GSHPx in the breast muscle of the H group showed a tendency to increase ( P 5 0.06 , 0.1). These results indicate that Eq injection in ovo does not affect the growth of broilers, but significantly improves the water-holding capacity of the muscle, especially in female broilers, which is related to the improvement of antioxidative status.

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“…Attributed to ingestion of isoflavone phytoestrogens, greatly enhanced oestrogenic potency by ruminal microbial demethylation of formononetin to equol was later established. In 1982, equol was reported in human urine [5], and subsequently, found to increase in response to soy ingestion in some, but not all human subjects [6,7], but abolished by antibiotic ingestion [8].…”

Section: Probiotics and Phytochemical Metabolism-the Role Of Gut Flormentioning

confidence: 99%

Probiotics in Human Health and Disease: A New Avenue of Understanding between Diet, Disease and Metabolic Disorders

Wilcox¹

2013

J Prob Health

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The identification of the weak oestrogen equol [7-hydroxy-3-(4′-hydroxyphenyl)chroman] in human urine

Cited by 229 publications

References 28 publications

Animal Models Impacted by Phytoestrogens in Commercial Chow: Implications for Pathways Influenced by Hormones

Animal Models Impacted by Phytoestrogens in Commercial Chow: Implications for Pathways Influenced by Hormones

The effect of equol injection in ovo on posthatch growth, meat quality and antioxidation in broilers

Probiotics in Human Health and Disease: A New Avenue of Understanding between Diet, Disease and Metabolic Disorders

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