Time-resolved fluoroimmunoassay for plasma enterolactone.
We present a method for the determination of the lignan enterolactone in plasma (serum). This compound, produced by intestinal bacteria from matairesinol and secoisolariciresinol in fiber-rich food, is a biomarker related to the intake of a healthy diet. The method is based on time-resolved fluoroimmunoassay using a europium chelate as a label. After synthesis of 5'-O-carboxymethoxyenterolactone the compound is coupled to bovine serum albumin and then used as antigen in immunization of rabbits. The tracer with the europium chelate is synthesized using the same 5'-derivative of enterolactone. After enzymatic hydrolysis and ether extraction the immunoassay is carried out using the VICTOR 1420 multilabel counter (Wallac Oy, Turku, Finland). No antiserum cross-reactivity with available lignans, isoflavonoids, or flavonoids could be detected. The intraassay and interassay coefficients of variation at different concentrations vary 4.6-6.0 and 5.5-9.9, respectively. The working range of the assay is 1.5-540 nmol/liter. We measured enterolactone in serum/plasma of 224 Finnish subjects: 98.8% of the subjects had values <100 nmol/liter, 38.0% had 20-39.9 nmol/liter, and 34.4% had <20 nmol/liter.
Adlercreutz
H
H
Institute for Preventive Medicine, Nutrition and Cancer, Helsinki, Finland.
Wang
G J
GJ
Lapcík
O
O
Hampl
R
R
Wähälä
K
K
Mäkelä
T
T
Lusa
K
K
Talme
M
M
Mikola
H
H
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000097:blood; D015200:Fluoroimmunoassay / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D017705:Lignans / Q000097:blood*; D012680:Sensitivity and Specificity
D017705:Lignans; D015107:4-Butyrolactone; C029497:2,3-bis(3'-hydroxybenzyl)butyrolactone