Urinary Profiles of Soy Isoflavone Metabolites in Women, Female Piglets and Female Rats Consuming Soy Diet

摘要

Objective:To investigate the urinary soy isoflavone metabolites from women, female piglets and rats fed with diet containing soy protein. Methods: Urinary samples from human and animals were collected after soy diet consumption. Identification for soy isoflavone metabolites in urine samples was processed using an Agilent-Bruker LC Esquire ion trap system. Quantification of aglycone and conjugated soy isoflavone metabolites were also analyzed using a method published previously. Results: Identification studies showed that aglycones and conjugates of soy isoflavone metabolites were found in women and porcine samples. Interestingly, glucuronide conjugate of equol, besides glucuronide conjugates of genistein and daidzein, were found in rat urine. Glu-curonide conjugate of equol was the major metabolite found in rat urine. A quantitative study showed that conjugated forms of isoflavones were more than 90% in woman urine, were between 80.5% and 84.5% in female porcine urine, and were less than 50% in female rat urine. Conclusion: Equol is the major metabolite found in female rat urine, but it is not found in woman or female porcine urine. Urinary profiles show that porcine model is more appropriate for mimicking human soy diet consuming studies.