A urinary profile study of dietary phytoestrogens. The identification and mode of metabolism of new isoflavonoids

Joannou, George E.; Kelly, Graham; Reeder, Anthony Y.; Waring, Mark; Nelson, Carolyn

doi:10.1016/0960-0760(95)00131-i

Cited by 272 publications

(206 citation statements)

References 34 publications

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“…The application of capillary electrophoresis tandem mass spectrometry to the detection of phytoestrogens shows promise of improved sensitivity and selectivity; however, this method is currently limited by the requirement for precise and accurate manipulation of submicroliter volumes (Shihabi et al, 1994;Aramendia et al, 1995 ) . The preferred technique for selective and sensitive quantitative analysis of phytoestrogens in biological matrices is GC /MS ( Joannou et al, 1995;Messina et al, 1997 ) . However, this method requires time -consuming cleanup, hydrolysis, and derivatization steps.…”

Section: Introductionmentioning

confidence: 99%

HPLC-MS/MS method for the measurement of seven phytoestrogens in human serum and urine

Valentín-Blasini

Blount

Rogers

et al. 2000

J Expo Sci Environ Epidemiol

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The elevated exposure of children to hormonally active dietary phytoestrogens has led to the need for rapid, sensitive, and precise assays for phytoestrogen metabolites in physiological matrices. Here we report the development of a high -performance liquid chromatography ( HPLC ) MS / MS method for the quantitative detection of seven phytoestrogens in human serum and urine. The method uses enzymatic deconjugation of the phytoestrogen metabolites followed by solid phase extraction ( SPE ) and reverse -phase HPLC. The phytoestrogens are detected using a Sciex API III heated nebulizer atmospheric pressure chemical ionization ( HN -APCI ) interface coupled with tandem mass spectrometry. This method allows the detection of the primary dietary phytoestrogens ( isoflavones and lignans ) in human serum and urine with limits of detection ( LODs ) in the low parts per billion range. The combination of tandem mass spectrometry and chromatographic separation of the analytes helps ensure the selectivity of the method. Stable isotope -labeled internal standards for all seven analytes improve the precision of the assay, resulting in interday CV values of < 10% for most compounds studied. The accuracy and precision of the method were monitored over time using quality control ( QC ) samples containing known amounts of phytoestrogens. The majority of phytoestrogens in human sera and urine are present as their glucuronide and sulfate conjugates. Therefore, the thoroughness of deconjugation for each sample was monitored by the addition of a conjugated internal standard and subsequent detection of deconjugated compound. This method proves to be efficacious for measuring baseline urinary phytoestrogen levels in the American population and should prove useful for assessing the modulatory effects of dietary phytoestrogens on endocrine disrupter action in children.

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Section: Introductionmentioning

confidence: 99%

HPLC-MS/MS method for the measurement of seven phytoestrogens in human serum and urine

Valentín-Blasini

Blount

Rogers

et al. 2000

J Expo Sci Environ Epidemiol

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“…Daidzein is converted into dihydrodaidzein (DHDE), equol and O-desmethylangolensin (O-DMA), and genistein is converted into dihydrogenistein (DHGE) and p-ethylphenol, which are less predominant metabolites (6) . These compounds and metabolites circulate through the blood and are excreted in urine usually within 48 h after ingestion (7,8) .In several studies, urinary isoflavones were found to be reliable biomarkers for isoflavone consumption (9 -14) , and the urinary appearance of isoflavonoids accurately reflected circulating levels when the timing of specimen collection was considered (15) . Urinary isoflavone excretion has been well researched in adults as a suitable index of isoflavone intake.…”

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confidence: 99%

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confidence: 99%

Overnight urinary excretion of isoflavones as an indicator for dietary isoflavone intake in Korean girls of pubertal age

Kim

Joung

et al. 2010

Br J Nutr

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Little is known about the bioavailability of isoflavones in children. Previous studies have shown that children excrete more isoflavone in urine compared with adults. Thus we examined the relationship between usual dietary isoflavone intake and the urinary excretion of isoflavonoids in Korean girls of pubertal age. Twelve girls each were selected from the lowest and the highest quartiles of isoflavone intake among 252 Korean girls aged 8 -11 years. Age, BMI and sexual maturation stage were matched between the two groups. Dietary intakes for 3 d by diet record and overnight urine samples were collected at baseline and at 6 and 12 months. Total and individual isoflavone (daidzein, genistein and glycitein) intakes were calculated from diet records. The parent isoflavone compounds (daidzein, genistein and glycitein) and their metabolites (equol, O-desmethylangolensin (O-DMA), dihydrodaidzein and dihydrogenistein) present in the urine samples were analysed using liquid chromatography -MS. Intake levels of total and individual isoflavone compounds were significantly higher in the high isoflavone (HI) group than the levels in the low isoflavone (LI) group (P,0·05). Urinary excretion of all isoflavone parent compounds was significantly higher in the HI group than in the LI group (P,0·0001). Among isoflavone metabolites, only O-DMA and total metabolites were significantly different (P,0·05). Total isoflavone intake was highly correlated with the urinary excretion of total parent compounds (r 0·68; P,0·01), parent compounds plus their metabolites (r 0·66-0·69; P,0·01) and total isoflavonoids (r 0·72; P,0·0001). In conclusion, overnight urinary excretion of total isoflavonoids is a reliable biomarker of usual isoflavone intake in Korean girls of pubertal age. Young Korean girls: Isoflavone intake: Isoflavone metabolites: Overnight urinary excretionIsoflavones have been associated with a lower risk of chronic diseases, including prostate, breast and colorectal cancer, CHD, osteoporosis and menopausal symptoms (1 -3) . Isoflavones are present in soya foods, mainly as glycosides. The major dietary isoflavones are daidzein, genistein and glycitein. Isoflavone glucosides are hydrolysed by intestinal b-glucosidases to produce aglycones (daidzein, genistein and glycitein) in the small intestine (4) . These aglycones are then absorbed by diffusion through the enterocyte and across the intestinal wall (5) and are further metabolised by the intestinal microflora in the large intestine. Daidzein is converted into dihydrodaidzein (DHDE), equol and O-desmethylangolensin (O-DMA), and genistein is converted into dihydrogenistein (DHGE) and p-ethylphenol, which are less predominant metabolites (6) . These compounds and metabolites circulate through the blood and are excreted in urine usually within 48 h after ingestion (7,8) .In several studies, urinary isoflavones were found to be reliable biomarkers for isoflavone consumption (9 -14) , and the urinary appearance of isoflavonoids accurately reflected circulating levels when the timin...

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“…ρ-Ethylphenol is the most predominant metabolite of genistein in sheep. In humans, dihydrogenistein and 6'-hydroxy-ο-desmethylangolensin are isolated and characterized as metabolites of genistein 22 . There are some reports of effects of intestinal bacteria on metabolism of isoflavones.…”

Section: Effects Of Intestinal Flora On Metabolism Of Isoflavonesmentioning

confidence: 99%

Effects of Intestinal Flora on the Metabolism and Absorption of Isoflavones

Tamura

2006

JARQ

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Soybean and soy foods are rich sources of isoflavones. Much attention has focused on isoflavonoids because of their beneficial effects on human health. Isoflavones belong to the group of phytoestrogens. Phytoestrogens are estrogenic compounds found in plants. Intestinal flora plays an important role in the absorption and metabolism of isoflavones. Some dietary components and chemical composition of isoflavones are also known to affect the absorption of isoflavones. Human metabolism and excretion of isoflavones following the consumption of soy products show considerable variation. The bioavailability of soybean isoflavones to women is dependent on gut microflora. Equol is a metabolite of daidzein produced by intestinal flora. Equol has many biological activities related to human health, and its production might be affected by compositions of diets and intestinal flora. To achieve higher production of equol from daidzein in the gut, control of the metabolic activity of intestinal flora might be of importance.

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A urinary profile study of dietary phytoestrogens. The identification and mode of metabolism of new isoflavonoids

Cited by 272 publications

References 34 publications

HPLC-MS/MS method for the measurement of seven phytoestrogens in human serum and urine

HPLC-MS/MS method for the measurement of seven phytoestrogens in human serum and urine

Overnight urinary excretion of isoflavones as an indicator for dietary isoflavone intake in Korean girls of pubertal age

Effects of Intestinal Flora on the Metabolism and Absorption of Isoflavones

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