Monoclonal antibody-based time-resolved fluorescence immunoassays for daidzein, genistein and equol in blood and urine: application to the Isoheart Intervention Study

TY - JOUR

T1 - Monoclonal antibody-based time-resolved fluorescence immunoassays for daidzein, genistein and equol in blood and urine

T2 - application to the Isoheart Intervention Study

AU - Talbot, Duncan C.S.

AU - Ogborne, Richard M.

AU - Dadd, Tony

AU - Adlercreutz, Herman

AU - Barnard, Geoff

AU - Bügel, Susanne Gjedsted

AU - Kohen, Fortune

AU - Marlin, Sandra

AU - Piron, Jerry

AU - Cassidy, Aedin

AU - Powell, Jonathan

PY - 2007

Y1 - 2007

N2 - Background: Time-resolved fluorescence immunoessays (TR-FIAs) for phytoestrogens in biological samples are an alternative to mass spectrometric methods. These immunoessays were used to test urne and plasma samples from individuals in a dietary trial aimed at determining the efficacy of dietary isoflavones in reducing the risk of coronary heart disease in postmenopaususal women.Methods: We estalished murine monoclonal TR-FIA methods for daidzein, genistein and equol. The assays could be perfomed manually or adapted to an automated analyzer for the high throughput and increased accuracy. Analysis of urine was conducted on nonextracted samples. Blood analysis was performed on nonextracted samples for daidzein, whereas genestein and equol erquired diethyl-ether extraction.Results: Comparison of monoclonal TR-FIA, commercial polyclonal antibody-based TR-FIA and gas chromatography-mass spectrometry showed correlations (r, 0.911-0,994) across the concentration range observed in the Isoheart sudy (50 mg/day isoflavones). The concentartions of urinary daidzein and genistein observed during intervention demonstrated good compliance and a corresponding incrase in serum daidzein and genestein confirmed bioavailability of the isoflavone-rich foods; 33 of th 117 volunteers (28,2%) were classified as equol producers on the absis of their urinary equol concentration (>936 nmol/L),and significant differences in the numbers of equol producers were observed between Berling and the 3 other European cohorts studied.Conclusions: The validated monoclonal TR-FIA methods are applicable for use in large-scale human phytoestrogen intervention studies and can be used to monitor cokpliance, demonstrate bioavailability and assess equol producer status.

AB - Background: Time-resolved fluorescence immunoessays (TR-FIAs) for phytoestrogens in biological samples are an alternative to mass spectrometric methods. These immunoessays were used to test urne and plasma samples from individuals in a dietary trial aimed at determining the efficacy of dietary isoflavones in reducing the risk of coronary heart disease in postmenopaususal women.Methods: We estalished murine monoclonal TR-FIA methods for daidzein, genistein and equol. The assays could be perfomed manually or adapted to an automated analyzer for the high throughput and increased accuracy. Analysis of urine was conducted on nonextracted samples. Blood analysis was performed on nonextracted samples for daidzein, whereas genestein and equol erquired diethyl-ether extraction.Results: Comparison of monoclonal TR-FIA, commercial polyclonal antibody-based TR-FIA and gas chromatography-mass spectrometry showed correlations (r, 0.911-0,994) across the concentration range observed in the Isoheart sudy (50 mg/day isoflavones). The concentartions of urinary daidzein and genistein observed during intervention demonstrated good compliance and a corresponding incrase in serum daidzein and genestein confirmed bioavailability of the isoflavone-rich foods; 33 of th 117 volunteers (28,2%) were classified as equol producers on the absis of their urinary equol concentration (>936 nmol/L),and significant differences in the numbers of equol producers were observed between Berling and the 3 other European cohorts studied.Conclusions: The validated monoclonal TR-FIA methods are applicable for use in large-scale human phytoestrogen intervention studies and can be used to monitor cokpliance, demonstrate bioavailability and assess equol producer status.

KW - Former LIFE faculty

KW - Fytoøstrogener

KW - TR-FIA

KW - Daidzein

KW - Genistein

KW - Phytoestrogens

KW - Isoheart

U2 - 10.1373/clinchem.2006.075077

DO - 10.1373/clinchem.2006.075077

M3 - Journal article

C2 - 17317887

SN - 0009-9147

VL - 53

SP - 748

EP - 756

JO - Clinical Chemistry

JF - Clinical Chemistry

IS - 4

ER -