Identification of equol producers in a Japanese population by high-performance liquid chromatography with coulometric array for determining serum isoflavones.
Using a method of high-performance liquid chromatography (HPLC) with coulometric array, we measured isoflavone levels in sera from seven volunteers before and after three days of ingesting Soyaflavone E (an isoflavones powder) and from 129 female farmers (Japanese Multiple Environmental Toxicants Study; JMETS). Results showed that the serum isoflavone concentrations rose dramatically after three days of ingesting Soyaflavone E in all subjects except for the serum equol concentrations in two subjects. The geometric mean concentrations of daidzein, genistein, and equol in the serum of 129 Japanese women were 25.0 ng/ml of daidzein, 94.1 ng/ml of genistein, and 9.6 ng/ml of equol. Interestingly, there existed two dominant groups in terms of serum equol concentrations in an independent manner of soy-derived product intake among the study participants.
Zhao
J H
JH
Center for Community Medicine, Department of Environmental Medicine, Jichi Medical School, 3311-1 Yakushiji, Minamikawachi-machi, Kawachi-gun, Tochigi 329-0498, Japan.
Sun
S J
SJ
Arao
Y
Y
Oguma
E
E
Yamada
K
K
Horiguchi
H
H
Kayama
F
F
D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004032:Diet; D004435:Eating; D060754:Equol; D005260:Female; D019833:Genistein / Q000097:blood; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage* / Q000096:biosynthesis / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D007564:Japan; D008297:Male; D008875:Middle Aged; D045730:Soy Foods; D011795:Surveys and Questionnaires
C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D007529:Isoflavones; D060754:Equol; C004742:daidzein; D019833:Genistein