glycitein and dihydrodaidzein

S-Equol is a metabolite of daidzein, a type of soy isoflavone, and three reductases are involved in the conversion of daidzein by specific intestinal bacteria. S-Equol is thought to prevent hormone-dependent diseases. We previously identified the equol producing gene cluster (eqlABC) of Eggerthella sp. YY7918. Daidzein reductase (DZNR), encoded by eqlA, catalyzes the reduction of daidzein to dihydrodaidzein (the first step of equol synthesis), which was confirmed using a recombinant enzyme produced in Escherichia coli. Here, we purified recombinant DZNR to homogeneity and analyzed its enzymological properties. DZNR contained FMN, FAD, and one 4Fe-4S cluster per 70-kDa subunit as enzymatic cofactors. DZNR reduced the CC bond between the C-2 and C-3 positions of daidzein, genistein, glycitein, and formononetin in the presence of NADPH. R-Dihydrodaidzein and R-dihydrogenistein were highly stereo-selectively produced from daidzein and genistein. The K

Topics: Actinobacteria; Coenzymes; Equol; Escherichia coli; Flavin Mononucleotide; Flavin-Adenine Dinucleotide; Genistein; Humans; Iron; Isoflavones; NADP; Oxidoreductases; Oxidoreductases Acting on CH-CH Group Donors; Protein Multimerization; Protein Structure, Quaternary; Protein Subunits; Stereoisomerism; Sulfur

1. Soybean is a common source of protein in many pet foods. Slow glucuronidation of soy-derived isoflavones in cats has been hypothesized to result in accumulation with adverse health consequences. Here, we evaluated species' differences in soy isoflavone glucuronidation using urine samples from cats and dogs fed a soy-based diet and liver microsomes from cats compared with microsomes from 12 other species. 2. Significant concentrations of conjugated (but not unconjugated) genistein, daidzein and glycitein, and the gut microbiome metabolites, dihydrogenistein and dihydrodaidzein, were found in cat and dog urine samples. Substantial amounts of conjugated equol were also found in cat urine but not in dog urine. 3. β-Glucuronidase treatment showed that all these compounds were significantly glucuronidated in dog urine while only daidzein (11%) and glycitein (37%) showed any glucuronidation in cat urine suggesting that alternate metabolic pathways including sulfation predominate in cats. 4. Glucuronidation rates of genistein, daidzein and equol by cat livers were consistently ranked within the lowest 3 out of 13 species' livers evaluated. Ferret and mongoose livers were also ranked in the lowest four species. 5. Our results demonstrate that glucuronidation is a minor pathway for soy isoflavone metabolism in cats compared with most other species.

Topics: Animals; Cats; Dogs; Equol; Estradiol; Ferrets; Genistein; Glucuronidase; Glycine max; Herpestidae; Isoflavones; Liver; Microsomes, Liver; Species Specificity

We evaluated the reproducibility and validity of the FFQ used in the Shanghai Men's Health Study (SMHS) for assessing dietary isoflavone intake, using multiple 24-h dietary recalls (24-HDR) and urinary isoflavones as the reference criteria, with data from the dietary validation study of the SMHS. A total of 196 study subjects completed the 24-HDR and 2 FFQ and donated a quarterly spot urine sample during the 1-y study period. Levels of urinary isoflavones were measured in a random sample of 48 study participants. The correlation coefficient between the 2 FFQ administered 1 y apart was 0.50 for soy protein intake and ranged from 0.50 to 0.51 for isoflavone intake. The correlations of isoflavone intake from the second FFQ with those from the multiple 24-HDR ranged from 0.38 (genistein) to 0.44 (glycitein), and the correlations with urinary isoflavone levels were 0.48 for total isoflavones, 0.44 for daidzein, 0.42 for genistein, and 0.54 for glycitein. The intraclass correlation coefficients for the 4 spot urine samples were 0.36, 0.42, and 0.40 for daidzein, genistein, and glycitein, respectively, and 0.62, 0.68, and 0.55 for their metabolic products equol, dihydrodaidzein, and O-desmethylangolensin, respectively. These results suggest that the SMHS FFQ can reliably and accurately measure usual intake of isoflavones, and that the levels of isoflavones in urine samples are relatively stable among men in Shanghai.

Topics: Asian People; Diet; Genistein; Humans; Isoflavones; Male; Middle Aged; Reproducibility of Results; Surveys and Questionnaires

Di-O-sulfates of six phytoestrogenic isoflavonoids, daidzein (1), genistein (2), glycitein (3), and the reduced metabolites dihydrodaidzein (4), dihydrogenistein (5) and equol (6) were synthesized. These compounds are known or potential inhibitors of steroid sulfatase enzymes. The new compounds were characterized by NMR and mass spectrometry.

Topics: Equol; Genistein; Isoflavones; Magnetic Resonance Spectroscopy; Phytoestrogens; Steryl-Sulfatase; Sulfuric Acid Esters